| Author | Message | ||
| Tim N (Timn88)
Advanced Member Username: Timn88 Post Number: 2552 Registered: 6-2001 |
I'm familiar with this material. i even developed a pneumonic device for remembering vector products (ijkij= I Just Know It's Junk, , its the best i could come up with. when writing these letters ina circle, you can figure out the direction of the cross product). I know about cross products but i just think of the magnitude of torque as t=rF sin(insert theta here). the direction of the torque is perpendicual to the plane of the force and moment arm. Damn, this just reminded me that i have a problem set to finish with moment of intertaia and rotational kinematics problems on it. oh, in HS it was always N/M, it wasnt until an intro engineering class until i first had to deal with english units in equations. i like the metric system more. | ||
| Rob Schermerhorn (Rexrcr)
Member Username: Rexrcr Post Number: 308 Registered: 11-2002 |
Tim, you're right about spring rate (lbf/in) vs. torque ft-lbf. As stated, spring rate is the spring constant (k) we learned in high school, a given force (lb) applied to compress a given distance (in this case, one inch). Torque is a force (F) applied to a rigid body about some axis. This force tends to rotate the body about the axis. Torque is usually represented by t = Fd, where F is force and d is the moment arm of the force. It is also the cross product of two vectors: t=r x F, where (x) represents cross product, not simple multiplication, and utilizes the right hand rule. This results in the example of tightening a wheel bolt, of the resultant force of 73 ft-lb directed in toward the center of the car, along the axis of the bolt, if you picture tightening with a wrench. And as we all know, a vector has both magnatude and direction. Pilots understand this better than most as their lives depend on it. To say a race car's velocity is 150 mph is technically incorrect, it should be 150 mi/hr north (include direction). (ohhh, I feel sleepy already...) | ||
| Tim N (Timn88)
Advanced Member Username: Timn88 Post Number: 2548 Registered: 6-2001 |
Spring rate is just the spring constant of the spring. AS said below it tells you hjow much force will displace the spring a given amount. this value is not torque. The wheel rate, judging by unit analysis (i dont know much about car math, just what i can carry over from physics) is how much a force will move the wheel a certain displacement. i guess it could be called "effective spring rate". this term isnt right, but it explains it. I also find it hard to beleive that anyone would pay $500 to $700 for a an OEM challenge rotor. you can likely a few brembo equivelents for the same amount of $. That is a ridiculous price. | ||
| Rob Schermerhorn (Rexrcr)
Member Username: Rexrcr Post Number: 307 Registered: 11-2002 |
For chassis tuning on the track: (from my post on the 360 Challenge thread). Warp mode is cross-chassis: left front - right rear and visa-versa. It's analogous to "heave" which is all four corners up or down at the same time, but its one diagonal pair up and the opposite pair down. This is typical corner entry, exit and rough-road surface dynamic situations. Weight transfer is only a function of CG height,track width, friction, latteral acceleration (centripital) and nothing else. It is easy to confuse "traction" with absolute weight transfer and also roll couple distribution. The ultimate goal for improved grip is no weight transfer, as what is lost from the inside wheel in friction force (normal to the road) is greater than what is effective "transferred" to the outside wheel force "pushing" this wheel down (normal to the road). I know this subject is very easy to get confused and lost in terminology. And it doesn't help when the definitive text on the subject is filled with formula and "geek speak". Most of what you as a driver experience can be related using principals we were all exposed to in high school physics. Though the difference is in the details, and obtaining fast solutions is the name of the game, which is why consultants are available in all industries, and I'm available for race car set-up consultation. Ask away  | ||
| Mitch Alsup (Mitch_alsup)
Member Username: Mitch_alsup Post Number: 374 Registered: 4-2002 |
Why are road cars soft and race cars stiff? Basically, you want to use as soft a set of springs as possible to maximize traction by keeping weight on the inside contact patch. {Consider an infinately stiff set of springs, any cornering will instantly transfer all the weight off the inside tire to the outside tire. Therefore, the inside tire supplies no traction and cornering is reduced. Now, consider an infinately soft set of springs; any cornering leaves all the weight at the original tire (lets ignore that the car rolls onto its bump stops). With both tires available to grip the road, traction improves. When a pair of tires shares the load, more traction is available than when one tire has more load than the other. This implies that you want as little spring as possible from a tire traction standpoint.} However, tire traction is also related to the camber angle of the tire with respect to the road. A tire leaning over at 45 degrees will provide little traction from the small contact patch at the edge of the tire, while a tire standing straight up will provide traction from its large contact patch of the entire tread width. Large displacements of the suspension arms can allow unwanted camber changes that would reduce traction. So spring rate (through the motion ratio) are used to find the ballance between too soft and too hard. Road tires can provide only around 0.9 to 1.0 Gs of cornering, while racing slicks can provide up to 1.5Gs of cornering (without aerodynamic assist). This extra cornering force causes more roll and thereby requires stiffer springs to keep the suspension in the 'low camber' change area of operation. Therefore, the appropriate spring rate is actually related to the amount of grip the tires can supply! In addition, racing cars are more woried about the handling characteristics at the limit, while road cars are more woried about the handling characteristics of a car with an unaware driver. So a set of springs optimal for a driver with his complete mental abilities focused on keeping the car out of the armco will not be optimal on a road car where the driver is listening the the radio and talking on a cell phone. | ||
| Rob Schermerhorn (Rexrcr)
Member Username: Rexrcr Post Number: 306 Registered: 11-2002 |
From my post on lowering:
As for ARB's, it is a torsion spring just like a helical (coil) spring. It contributes to wheel rate in roll, and contributes to overall roll-couple distribution (roll frequency). ps, the motion ratio for 348 and 355 is effectively the same (variation in camber gain due to rear suspension geometry modification in 1993). Hope this helps, please ask more if interested. | ||
| Rob Lay (Rob328gts)
Board Administrator Username: Rob328gts Post Number: 3870 Registered: 12-2000 |
I'm sorry, can you explain wheel rate Rob? I understand lb/in. when it relates to torque or spring rates, so I guess it's related, but is sway really torque? Is it just how many pounds of force the bar can withstand per inch? Thanks, I'm always trying to learn. | ||
| Rob Schermerhorn (Rexrcr)
Member Username: Rexrcr Post Number: 302 Registered: 11-2002 |
I found my F355 Challenge anti-roll bar information: This was a front and rear upgrade. The old front bar is approx 0.875 inch dia, 35 " length, 7" arm, 0.5 motion ratio, yielding a WHEEL RATE (the only spec that really matters) of 96.5 lb/in. The old rear bar is 0.669" dia, 39" long, 7.75" arm length, 0.6 motion ratio, yielding a wheel rate of 35 lb/in. New front bar is 0.945 inch dia, wheel rate of 131 lb/in. New rear bar is 0.748 inch dia, wheel rate of 54 lb/in. The 0.945 front bar is the only way to go, the car needs front roll stiffness. Your choice on rear bar, they're both quite wimpy and one can make the argument that they only contribute additional unsprung weight, not roll couple distribution. For point of reference, the wheel rates with the big front spring and soft rear (2200 and 700 lb/in, respectively) is 1078 lb/in front and 506 lb/in rear. So you see that relative to wheel rate of the springs, front bar does contribute some, rear bar relatively much less. Also to put all these numbers into perspective, the stock wheel rates on a 3x8 series are around 100 lb/in. Very soft in comparison. | ||
| Rob Schermerhorn (Rexrcr)
Member Username: Rexrcr Post Number: 296 Registered: 11-2002 |
Bret, do you have the timing specs? I was not aware of differences. Other than the entirely different OBDII specs, were there are vast diferences, but Challenge never went there, they stayed OBDI even to 1999. | ||
| BretM (Bretm)
Advanced Member Username: Bretm Post Number: 3204 Registered: 2-2001 |
The cam timing is different on street vs. the challenge cars, same parts just different setup, other than that it is all the same in the engine itself as has been said. | ||
| Rob Schermerhorn (Rexrcr)
Member Username: Rexrcr Post Number: 295 Registered: 11-2002 |
No internal engine differences from street to Challenge other than the whole OBDI not II and not street legal stuff. I believe K&K and other's will insure on-track. Someone was/is pitching this to Challenge drivers. Part of it was liability, to protect your assets (as*) if you injured another driver. I concure on the passenger seat install. Same brackets and seat will fit in passenger side. The OEM one's fit very well. You may also need to install harness mounts, too. Fire system vs. just bottle highly recommended. I designed a nice window net available from M&R Safety Products. It attaches to the lower door bar and you fit it with a seatbelt type release on top attached to the cage. It's black tight mesh type and virtually transparent. They should still have the design from 1997. Customer at that time was Lake Forest Sportscars. They'll do anything custom and it's affordable. | ||
| Kevin Butler (Challenge)
Junior Member Username: Challenge Post Number: 107 Registered: 9-2002 |
Jon, thanks!! I do have a helmet (Arai Quantum full face) but it is M-rated (for my 2-wheeled madness). Incidentally, I wore this in the F40 although I probably shouldn't have. Kevin | ||
| Matt Karson (Squidracing)
Member Username: Squidracing Post Number: 427 Registered: 3-2001 |
I have full comprehensive, trailering, fire (off track only, paddock is covered), theft, stated value, and collision if and only if someone at the track would run into my car, when my car is parked off of the track proper. It doesn't cover anything else. It cost me $600/year with $1,000 deductable, with stated value of $100,000. In my opinion, playing the 'cross your fingers and hope they pay' insurance game is a waste of time and money. | ||
| Jon P. Kofod (95f355c)
Member Username: 95f355c Post Number: 480 Registered: 8-2001 |
Rob, First off Rob S. would be the one to ask about engine differences. The engines are the same but I remember when they converted my car they asked me if it would ever see street duty and I said no so they did change some things in accordance with the Challenge rules but I can't remember what it was. Might have been something with the manifolds. #2 Yes I insured my 95 for a while but to be honest unless you title it and register it and have license plates I can't imagine they would pay. You would have a hard time convincing an insurance company that despite being street legal that you drive the car primarily on the road and use it occasionally for DE's. Also many insurance companies now have very specific clauses to exclude track damage. One insurance company refuses to honor any claim for a vehicle damaged while driving on a track used for racing, even if the accident did not happen during a race (i.e. DE's track days or just a parade lap at Indy). Talk to Matt K. he has insurance on the car for theft and transport to and from the track. #3 None came with a passenger seat. If you want a real OPM Challenge seat with the stiching and logo they run about 2-3K. You can buy the same seat from OMP without the Challenge logo for about $1200 in kevlar and $800 in carbon. Brackets are the same as driver side and it installs the same way. You may need to relocate the fire bottle system if it's in the center of the passenger side. Jon | ||
| Matt Karson (Squidracing)
Member Username: Squidracing Post Number: 426 Registered: 3-2001 |
I believe you would be able to insure a 95, but getting paid on a claim is a totally different matter. I would highly doubt you would get paid. My car came with only the drivers seat. I put in a second seat if there is a special person (ie: female) who really wants a ride, otherwise I only have one seat. Too many liability issues involved. | ||
| Rob Lay (Rob328gts)
Board Administrator Username: Rob328gts Post Number: 3821 Registered: 12-2000 |
Couple questions... 1) Is there anything about just the engine that is different from a street car. Just wondering in case I want to pick up a spare engine. 2) Does anyone insure their Challenge cars? If you have a title and VIN from a '95 car I think it would be insurable. Would they pay if there was an incident? 3) Did the Challenge cars race with a passenger seat? If not, I for sure want to add one. Are 4 bolts through the floor adequate? Thanks. | ||
| Rob Schermerhorn (Rexrcr)
Member Username: Rexrcr Post Number: 291 Registered: 11-2002 |
Jon, great info. BTW, unless you have radical engine mods like increased compression or cam timing changes to increase BMEP, the engine's tuned for 93 unleaded pump fuel. One can run the fuel at the local corner station, and I've brought empty 55 gal drums just to fill at the station and have the fuel as needed without wasting time. If you have the budget, the best fuel IMO is Phillip's 100 octane unleaded race fuel. It's a bit more than what the engine needs, but if you're concerned over quality or consistency or have tweaked the ignition timing or forced induction, this is your stuff. Pricey at $4 per gallon. Fuel information can be found here: http://www.kartshop.com/mall/phillip/phillips.html | ||
| Jon P. Kofod (95f355c)
Member Username: 95f355c Post Number: 478 Registered: 8-2001 |
Kevin, The ride is free of charge. Just email me two weeks before the event so I make sure you get a spot. Have a few other folks on the list but your first since you asked me back in December. One other F-chatter is also getting a ride. Do you have a helmet? Hope to see you there. Regards, Jon | ||
| Kevin Butler (Challenge)
Junior Member Username: Challenge Post Number: 106 Registered: 9-2002 |
So Jon, can I give you about $27 for fuel for 5 laps at the April event? :-) | ||
| Jon P. Kofod (95f355c)
Member Username: 95f355c Post Number: 477 Registered: 8-2001 |
Rob, Make sure that is not a "replica" wing. No way there should be any flex in the wing at all if it's a factory wing and as Rob mentioned make sure they installed the correct braces running forward on the inside of the engine bonnet. As for $2500 a day that sounds way too high unless you are paying dealer inflated prices for parts and maintenance. Here is the average run down of a weekend's costs assuming all goes as planned. Tires $400 (used with one heat cycle) last two weekends so $200 per weekend Pads $340 (Performance Friction $167 per axle) Last two weekends so $170 Front Rotors $720 ($367 per rotor) Last two weekends maybe three so cost is about $360 Rear Rotors $720 last twice as long $180 Fluids (Oil, trans fluid etc..) $50 per weekend Transport $100 per weekend (Local track 80 miles roundtrip) Gas at the track $200 per weekend. I don't include hotel as expenses related to running the car. Let's face it if I couldn't afford the Hotel expense I would sleep in the trailer or truck and proable wouldn't have a Challenge car. The big item you guys are discounting is the gas to run the car. If you run 93 octane and bring a bunch of gas jugs that you filled up at the corner gas station you might get away with $100-120. $80 is way too low unless your rev needle is stuck at 3000 rpm's and below. If you use 100-115 race gas and get it at the track figure at least $200-$250 for a full weekend if you drive it hard. Average cost to fill up my car with 115 Octane is about $70 and I typically fill up minimum three times or more. So total is about $1600 a weekend assuming a $350 track fee (about average). That equates to $800 a day but I am going to say $1000 per day if we throw in other items that last longer but need to be replaced during the course of a season like a new clutch. Now if you get stuff from the dealer well then it could be more like $2000-$2500 per day. PZero slicks from most dealers are $400-$500 each. OEM Challenge rotors range from $500-$700 each from the dealer. Pads are around $300 per axles and so on. Do the math, $2800 in rotors and $2500 in tires divided by three weekends is about $850 per day for tires and rotors alone and we haven't even gotten to pads, oil, gas and the rest so that's where it gets expensive. Regards, Jon P. Kofod 1995 F355 Challenge #23 Hope this helps! Regards, Jon P. Kofod | ||
| Rob Schermerhorn (Rexrcr)
Member Username: Rexrcr Post Number: 286 Registered: 11-2002 |
RobL, The F355 Challenge wing is pretty solid. The installation includes two braces running forward on the inside of the engine bonnet and "camlock" 1/4 turn fasteners to tie down the aft of the bonnet. BillyB: I was referring to an aftermarket gate lockout, not the stock "push and shift". | ||
| Rob Lay (Rob328gts)
Board Administrator Username: Rob328gts Post Number: 3803 Registered: 12-2000 |
No, I have the FerrariChat.com window banners and just the logo on the above. If you want me to create something else, please let me know. I didn't know you had a 355 Challenge too?  $2,500 a day. That's obsurd, even if you are spending $500 for transportation. I have some experience with this because of my Rx7 race car, here's my weekend (2 day) expenses for that... Entry Fee $250 Gas (transport & race) $80 Hotel $130 Food and Drink $80 Tires ($450/3 weekends) $150 Misc. Parts & Maint. $100 --- Total: $790 Now here's what I would expect the Challenge car to run a weekend... Entry Fee $250 Gas (transport & race) $80 Hotel $130 Food and Drink $80 Tires ($1000/2 weekends) $500 Misc. Parts & Maint. $500 --- Total: $1540 | ||
| Kevin Marcus (Rumordude)
Junior Member Username: Rumordude Post Number: 126 Registered: 9-2001 |
It is averging me around $2500/day to run my car. However, about 500 of that is just related to transportation. but when you factor in the tires/general maintenance it works out to around 2500. Rob, do you have any nice .pst's that i could use to make some ferrarichat logo's that i could stick on my car? | ||
| Rob Lay (Rob328gts)
Board Administrator Username: Rob328gts Post Number: 3800 Registered: 12-2000 |
There was a 355 Challenge I was looking at. How strudy are the rear spoilers supposed to be? I guess I was surprised it wasn't rock solid when I grabbed it. It wasn't loose, but had a little flex in it and seemed a little fragile. Also, what special tools should I start collecting. Anything custom to do pad and rotor changes? I just have a regular tool set and a brake piston pusher. Anything else I need? Thanks. Hopefully some more news this week. I still need many sponsors. There's no limit. Besides acquiring the car I estimate about $1,500 to run it a weekend and then I'm looking for an enclosed trailer right now. http://www.ferrarichat.com/discus/raceteam/index.htm | ||
| Matt Karson (Squidracing)
Member Username: Squidracing Post Number: 422 Registered: 3-2001 |
Rob....try to get a lockout plate which covers the reverse/1st and second. You will almost never need second gear once you are moving (at least at Watkins Glen/Pocono/Lime Rock/Summit Point. I'm changing mine this season to cover those I mentioned. Regarding my doing my own major service....yeah, I have an experienced mechanic giving me the orders. I just do as he says. Thing is, once you've done it once, you realize how easy it is. Now....I wouldn't do a rebuild myself, but removal/replace of a 355 motor is no big deal. Tensioner bearings and belts are easy as well....just a little more technical. | ||
| billy bob (Fatbillybob)
Junior Member Username: Fatbillybob Post Number: 211 Registered: 8-2002 |
Rex Rob , Reverselockout there. Ferrari has not redesigned shifter box since 1949. Since the addition of facsia center consoles the lock out does not work. Take your gate off and you can see the detent in reverse. If the 1/8" plastic is off the console and the gate is screwed to the shifterbox I.E. like the old days the reverse is locked out. My lock out works but I have a 348 challengeish car with no interior. | ||
| Rob Schermerhorn (Rexrcr)
Member Username: Rexrcr Post Number: 285 Registered: 11-2002 |
Reverse-first lockouts are common, but not a Ferrari supplied part. | ||
| Rob Lay (Rob328gts)
Board Administrator Username: Rob328gts Post Number: 3770 Registered: 12-2000 |
So reverse really works, it just helps you from making an expensive mistake? Thanks. | ||
| James Glickenhaus (Napolis)
Member Username: Napolis Post Number: 661 Registered: 10-2002 |
All challenge cars that don't want to have 20M trans bills. Sal at WWOC makes one that covers up 1st as well. | ||
| Rob Lay (Rob328gts)
Board Administrator Username: Rob328gts Post Number: 3769 Registered: 12-2000 |
A challenge car I was looking at had a little tab over the gate for reverse. Do all the challenge cars have this? Do challenge cars have reverse and this is just a flip tab? Thanks. | ||
| Rob Schermerhorn (Rexrcr)
Member Username: Rexrcr Post Number: 284 Registered: 11-2002 |
Jon, your rear wheel HP numbers show that it is likely there is more than 18% drivetrain power absorption due to friction. I do believe that virtually all F355's will dyno within 10 HP assuming top mechanical condition. And they'll do it for a long time, too; very durable motors. As for spring choices: due to the nature of Challenge and non-professional drivers/owners, it was sometimes difficult for me to set up the chassis based on the quality of feedback I'd get (which is why I loved the 360 Challenge with integral Marelli data acq systems). The optional spring rates, and the resulting wheel rates, are similar enough that changing springs is almost a fine tuning option. Generally (and I hate making generalities on set-ups) the softer rears give better balance on rougher tracks, slightly better corner exit, and also a softer car is easier for a less experienced driver. The chassis really responds well to placing the majority of roll stiffness up front, hence the stiff front springs, lots of packers (smooth track) and later, the optional larger front ARB. As for tire pressures: Pirelli always recommended hot pressures in the 35 psi range, but they're conservative and want to see long life and safety. As I mentioned before, less experienced drivers respond better to softer cars. So, with this in mind, plus pyrometer and alignment data, and the stopwatch, I tended to run less pressure than Pirelli. IMO, a top driver will be faster on the Pirelli's of 1995 - 2000 with higher pressures. But the "edge" will be sharper, response-wise. It takes a very sensitive and experienced feel to take advantage of all the grip afforded by the Pirelli slicks. ABS: The OEM Ferrari system after Challenge reprogramming, is an advantage, and I always ran ABS, even on the 348. ABS will compensate for frictional changes much faster than a driver's brain. The only time I will not run ABS is with an unsophisticated system which responds too slow, or is not programmed to take advantage of the available grip (race tires) or is biased incorrectly. | ||
| Jon P. Kofod (95f355c)
Member Username: 95f355c Post Number: 474 Registered: 8-2001 |
Rob, Curious what the average was of all the 355 C's you dynoed. The 335 figure seems well above the average figure for most I have seen. My 95 355C (OBDI) dyoned 319 at the rear wheels with the stock chip. What really shocked me was my TAP chips actually lost me 16 horsepower over stock. I am also curious why you ran the softer springs in the rear. I have the stiff springs front and rear. Do the softer springs in the rear cure some of the exit oversteer or was it done to tame the car in wet conditions. Also you forgot to mention the ABS debate I rasied in the other post. I ran with mine disconnected for the first year or so but then had it reconnected after Glen Marquis at FOW said Earle and Kenton and the other front runners were all faster with it on. Last question! I have heard much conflicting data about "hot" tire pressures. I realize it changes at every track due to a number of conditions but I was told by Tony at Algar never to go over 32 1/2 in rear and 31 1/2 front. Jim Kenton told me he ran 33-34 in the rear and about 32 in the front on average. Also talked to one of Shelton's crew who said they used lower tire pressures all around. I have found that Tony's numbers (hot) worked best at Summit Point and the Glen. Thanks for your wealth of information. Regards, Jon P. Kofod 1995 F355 Challenge #23 | ||
| Matt Karson (Squidracing)
Member Username: Squidracing Post Number: 421 Registered: 3-2001 |
"Does it push in hard corners? Any traction problems on acceleration? How is the feel at the limits?" I have my car dialed in very neutral. The only times I push that I experience is taken care of with the correct footwork. Regarding throwing the car around, the car has great throttle response, and will push the rear end out in a very predictable manner. You just need to get used to the character of the car. Rexrcr...thanks for the info. | ||
| Rob Schermerhorn (Rexrcr)
Member Username: Rexrcr Post Number: 276 Registered: 11-2002 |
Matt, I'm going on memory here, I believe I drilled and tapped 1/8 " NPT into an unused boss on or near the thermostat housing. As you know, Challenge cars do not have a thermostat, only a controlled restriction to flow and blocked bypass. Switch is available at any Hobbs dealer or buy a kit at http://www.pegasusautoracing.com PN:1009 $53.89. RobL: I converted a 1996 OBDII engine from a wreck to OBDI spec as a spare for my customer's F355C. We dyno'd on an engine dyno at 409 BHP (flywheel). Assuming 18% drive train loss equates to 335 at the wheels. I worked with Ted Wentz on some of the electrical issues of adapting the car's wiring harness to work outside the chassis, and in conversation, Ted stated he'd expect to see about 405 - 410 BHP flywheel. BTW, if anyone is contemplating this conversion, it can be done with bolt-on parts. Items to change are: Injectors Crank pulley Exhaust manifolds Fabricate new crack trigger bracket for second pickup Crank position sensor Wiring harness can be adapted or replaced Chassis dynamics: The F355 in Challenge specification is a nice package to work with in dialing in to track conditions and driver preferences. Just like many other proper race cars, it does tend to push in low speed turn in, and due to weight bias, one must watch for high speed exit oversteer, though this is totally manageable. The car is a delight when dialed in and is not too difficult to find the sweet spot. It is ride height sensitive and consequently chassis rake should be monitored. I always ran the stiffer of the two optional springs in the front (2200 lb/in) and usually the softer rears. I always ran the optional larger front ARB available in 1998. You want the chassis as low as practicable. With Pirelli slicks, about 2.5o negative front camber, 3.2o negative rear camber. Slight toe out in front, though this is driver preference for "feel" in turn-in, not ultimate grip. 45 minutes total toe in rear, this is for traction and high speed cornering stability. I have run as much at 1 degree total toe in rear. I'm out of time on this message... more later. | ||
| Rob Lay (Rob328gts)
Board Administrator Username: Rob328gts Post Number: 3736 Registered: 12-2000 |
Everyone, thanks so much for all your valuable information. I owe you. Has anyone ever had their 355 C dynoed? Matt, how did you go about doing the major service for the first time? Did you have someone with experience walk you through it? Also, now that we've covered the technical aspects of the car I would like to hear about the driving nature of this car. Does it push in hard corners? Any traction problems on acceleration? How is the feel at the limits? (my 328 on street tires and orginal suspension is nearly impossible to spin as the feedback is so good) | ||
| Matt Karson (Squidracing)
Member Username: Squidracing Post Number: 420 Registered: 3-2001 |
Rob Scherm...that water pressure wire is a GREAT idea. Totally save an engine. How would I install one? Where would the sensor come from for that? | ||
| Rob Schermerhorn (Rexrcr)
Member Username: Rexrcr Post Number: 273 Registered: 11-2002 |
I also highly recommend a cooling system pressure warning light. It's activated by a Hobb's switch that closes below 5 psi. This will save an engine if a hose blows and catch the damage before the temperature gets high. Wire to a blue light (get it, blue, water ;-) ). Ohh, and suspension packers: No time for detail, but packers are great for tuning this chassis and are legal for Challenge therefor for T1 also. These are plastic shims placed on the shock rod below the bump rubber. More later.... | ||
| Jon P. Kofod (95f355c)
Member Username: 95f355c Post Number: 472 Registered: 8-2001 |
This is turning into a great post w/ lot of information. I am just out the door to the airport and will have to keep it short. Rob: thanks for all the info. My car is a 95 and Ferrari of Washington had a copy of the manual you refer to. They asked me at the time of the conversion if the car would ever be used for street use again and I told them no. My car has the reinforcements in the front suspenion you mentioned as well as a few other items that were engine related. One thing you didn't mention that I am sure you came across was the issue of running the ABS or disconnecting it. I was told that the guys up front (Kenton, Earle, McCormick) all ran faster laps with it on but that some folks had it disconnected. Is this true? Matt: Hey buddy get ready for more snow! We got about 5 inches this morning and I spent all last weekend prepping my BMW for Summit Point this weekend. Figures! I second what Matt said about the gauges. Check em' that's what they are there for. Take a break on the straightaway's and look at your gauges. Anyway it's off to the airport and away from this snow, if only for a day! Regards, Jon | ||
| Matt Karson (Squidracing)
Member Username: Squidracing Post Number: 416 Registered: 3-2001 |
I forgot something.....I mentioned how prepare for the event (oil/air/pad thickness/gauges/etc..), what I do during the event (pressures/gauges/etc...), but I didn't say anything about what I do to ensure the car is put away properly!! If there is anything left of my tires, I add air to them, as they will drop pressure when the cool down, possibly causing damage...I put the car back in the trailer....strap it down....quietly go up to it....pet it a couple of times....tell it how much fun I had RESPECTFULLY SPANKING THE LIVING SH*T OUT OF IT, and how much I look forward to doing it again really soon. I feel the love coming right back to me. What a car. Ok, I'm a little strange...I can deal with that. | ||
| Matt Karson (Squidracing)
Member Username: Squidracing Post Number: 415 Registered: 3-2001 |
Ohhhh.....to only have been in the sun!! My kingdom for some heat!! No, unfortunatly I've been here freezing my ass off. Rob, this thread has a great amount of information in it. My thoughts are..... I've never had a clutch problem. This issue is directly related on how one works their clutch. I am like Jon, in that I am off my clutch as quickly as possible. The worst use of my clutch is when I load it on the trailer. I find the 355 gearbox to be very sturdy (knock on wood). Would I do 5 - 2 downshifts on a regular basis? No. But I find it to be a sturdy unit. The Speedline wheels are sturdy as well. Tires....well tires are tires....chaching$$. I do oil changes after 2 events, but would like to be able to do them after each event. I just don't have the time, and I believe that the oil can stand 4 days of track time. Brakes: I bleed my brakes every event, and flush my system every 4 events. As Jon can attest - I don't use my brakes until it is necessary. THEN I USE THEM. I've never (knock on wood) had a problem with my brakes. For the record, I do use my brakes in subtle ways as well (pivoting the car mid turn, initiate trailbraking, throwing the ass end around, etc...) I check my air pressures SEVERAL times a day. Actually, I check my pressures (and adjust them when dialing the car in) all day long. I go over my cars nuts and bolts over the course of the season. On the motor issue - I do my own major service every other season. I put on 30+ track days each season, and am comfortable doing the major every other season. I pay VERY CLOSE ATTENTION to my gauges. If I were ever to see anything that is out of the ordinary, I would shut it down right away. Cheaper that way. I'm a big fan of the 355. I love the way the car handles, how consistent it is, how predictable it is, and how much it LOVES BEING WORKED HARD. Just know the right way to ask of it what you like, and it will gladly give it to you. Temps - my water doesn't really stray from 195 degrees. Oil temps are different...really depending on the day. But they never go anywhere as high as the 348's oil temps. I think I would get as high as 210 degrees, but I'm not exactly sure of that. Maybe Dennis and Jon can help out with this. As far as what I would look to learn about regular maintenance - changing pads, bleeding/flushing brake system, changing rotors (easier than you think), which nuts and bolts to check. Although the gearbox is a closed system, I would have the mechanic show you where the gearbox 'dipstick' is, and would check it a couple times a season. How to do an oil change. Also, if you need to do a clutch change...it is NOT always necessary to do the slave cylinder. If this is the case....doing a clutch job yourself should take a few hours, and the cost of the plate. This brings us to the question - are you going to do your own major services? If you have the lift, it is really not a big deal. It will take you 5 hours to remove the motor, 2 hours to do the belt/tensioner bearing change, and 5 hours to replace the motor. Actually, I enjoy doing the work. I can imagine I've left out some other ideas, and when I think of them...I'll post again. I think it's great what you are doing, and you picked the right (355) car. I don't know if you already bought the car, but this is a very difficult endeavor. Remember, you will get what you pay for. But then again, we all know the story with the cars we love. Good luck pal! | ||
| Rob Schermerhorn (Rexrcr)
Member Username: Rexrcr Post Number: 270 Registered: 11-2002 |
From my experience: 1995 Challenge cars were imported as road legal though all did at one time have the complete kit installed. These are not converted street cars. If you find an original Challenge manual, it will show the differences between the factory Challenge and "how to" convert a normal road car. All factory Challenge have structural reinforcements to the front suspension, the spring rate in front is 2200 lb/in, the normal road cars require removal of the upper spring/shock mount and welding in a beefier component. I beleive there may only be a couple (Peter Sach's is one) documented truly converted from normal street production 1995 Challenge in the USA. BTW, the 1995 Challenge came with the AC compressor, hoses and condenser in a box, not installed. There are no 1996 Factory Challenge in the US as the 1995's did not all sell until 1996. I managed the last 1995 sold, a red/tan, originally campaigned by Tom Murphy in Challenge, then in SCCA T1 (Runoffs podium in 1998), then sold to a gentleman on the west coast and converted back to Challenge roll cage. The front and rear bumper covers are Kevlar, not carbon fiber, though carbon ones were/are available, though technically illegal for Challenge. The undertrays are fiberglass originally, which is good 'cause they get torn up with an agricultural excursion. The fastest drivers ran the wing at zero, or +2 at a slow track. There was an upgrade to the oil cooling system in 1997 that eliminates the oil to water and uses a conventional oil to air heat exchanger. Before the authorized kit was released, teams could fabricate their own version, though it was to be replaced in '97 to remain legal. Manual control of cooling fans is standard and recommend you run at all times on track. They also remain thermostatically controlled. For T1 I recommend disabling the shock solenoids and manually adjusting the Bilstein's. You must make adjustments and lock the adjuster in place (I used RTV silicone) or the wedge adjuster will move to full soft by the fluid movement. I recommend starting with the rear full stiff, the front to 80% full stiff. The adjuster only rotates 90o from full soft clockwise to full stiff CCW, so the adjustment is very sensitive. I'm certain someone can build a solenoid controller to manually adjust from the cockpit. There is an upgrade to the ABS ECU in 1998, very important. Upgrade to quick ratio steering and pump matched to this rack. Larger front ARB, too. This was part of one large update kit mandatory for 1997 which included the wing. Brake rotors are available from any Brembo dealer, I recommend running slotted only, not drilled, unless rules prohibit otherwise. I have run Performance Friction and Pagid pads. I like the PFC's best, but this is more driver preference for pedal feel than outright performance improvement. The Pagid R4-2 (blue) is the OEM Challenge pad. SCCA homologated the complete Challenge specification with the exception of tires. They may have adjusted the weight, though I ran the Challenge weight in 1998. | ||
| Dennis (Bighead)
New member Username: Bighead Post Number: 17 Registered: 2-2003 |
Jon -- yup, I was there! I recognize your car. As for me, I have yellow challenge wheels -- I was probably the slowest Ferrari in Red (though faster than that 512bblm! :-) Bob Hatch from Hatch and Sons in Wayland, MA was also there, and he runs the same setup (stock 355, used CH Pirelli slicks on Challenge wheels), but his wheels are white (his car is red), so it may have been him -- but he runs in Blue. Heck, I'd probably run in blue if only to give my point-by arm a rest :-), but my wife shares the car with me and she runs in blue... so I'm 333SP bait! And yes, John Tirrell is my mechanic. We usually park with the guys from Connecticut (Peter Lombardo and Joe Capasso). John is working on Alan Vernon's 355 CH right now; watch out when John's done, Alan's going to be even faster. Please tell Matt I said hello. He saved the last day for us; I ran down to the cord on one slick, and bought a set from Matt and Chris. Had to drive the friggin car down to Elmira to get it mounted, but, hey, we could run! I've got 3-4 sets of slicks left in the garage... hope they last at least half a season for me. As for the 512bblm -- you're absolutely right, Bob IS really fast in it (in the 1 out of 4 sessions when he isn't rebuilding it :-)... but it wasn't his car that I passed. I was on this guy's tail for 2 laps or so, finally got by him between 9 and 10 (and to answer the next question from the rabble, NO, he wasn't going into the pits! :-) Like I said, he probably wasn't running that well, because that's a damn fast car, and I'm certainly not a particularly great driver.... vty, --Dennis | ||
| Jon P. Kofod (95f355c)
Member Username: 95f355c Post Number: 471 Registered: 8-2001 |
Dennis, We must have run together at the Glen in September. I was also in the Red run group along with fellow F-Chatter Matt Karson and a bunch of other Challenge folks. What car were you in? Was it the red 355 with the white Challenge wheels? Is your mechanic John Tirell by chance? He has a black 355 C from Germany. You can see a picture of my car in my profile. I think we ran together. The 512 BBLM you passed was likely Bob Coates NART car. It could have been his wife driving. Trust me that car is fast when driven right (or running right). By the way if you were getting your used Pzero's from Bob Chick he is no longer selling them. Pirelli warned him to stop selling them to us so we are now using the Dunlops which I think suck. Only other alternative is to get new ones from Bob Woodman at $260 a pop. Hubert: I use Hoosiers on my BMW club racer but on the Challenge car I only use real slicks. The Hoosiers are nice R compound tires but they are closer to a street tire than a race slick. They also have a very lightweight rubber (carcass) construction that doesn't hold up well to the abuse of a Challenge car. Hoosier makes very good race slicks but they are very expensive and hard to come by. Tire Rack sells the R compound for $220+ a tire. I get used slicks with one heat cycle on them for $100 a tire and they last longer than the Hoosiers. Regards, Jon P. Kofod PS: Mr. Karson must be on vacation as I am sure he would be chimming in with his advice. Probably sitting on a warm beach somewhere laughing at us trying to shovel our way out of 3 feet of snow. | ||
| Hubert Otlik (Hugh)
Member Username: Hugh Post Number: 549 Registered: 1-2002 |
dennis & jon- for the hpde setting have you considered using hooisers? must be cheaper than the pirreli slicks. rob- email matt karson, he does all his own maintenance on his 355c, and should have a great deal of insight on that end, as well as race setup, etc | ||
| Dennis (Bighead)
New member Username: Bighead Post Number: 14 Registered: 2-2003 |
Jon, excellent information -- thanks! Two further points: Rob, FWIW, I hang out at the track with a half-dozen or so 355 CH drivers and a handful of 360CH drivers (most are just using these cars for DE-type track events, not playing in the CH series). The informal consensus is that the 355 CH is a much more stable, fun car to drive on the track than the 360CH. The 360CH is significantly (as in WAY) faster. But keep in mind that, ultimately, the 355CH is a street car converted (more or less) into a street car, while the 360CH is mostly a race car. And used 360CHs can be had for not much more than $125k, and unraced versions aren't that much more expensive. But fixing them and getting parts is a LOT more expensive. 2. In agreement with everyone about the race rubber. Being a cheap sumb1tch, I bought a bunch of sets of used Challenge Pirelli slicks. Worthless to Challenge racers, but plenty fine for little 'ole me to use on my 355B. Each set is worth a weekend or so, with both me and my wife driving in different sessions. Had lots of fun in Red, passing a 512BBLM at WGI last September... (though he was probably running on only 6 cylinders). With even used slicks on my stock 355, I can keep up with 996 Turbos and most new Corvettes on Z or W rated street tires. vty, --Dennis | ||
| Jon P. Kofod (95f355c)
Member Username: 95f355c Post Number: 468 Registered: 8-2001 |
Rob, What works best for me is to do the latter (gas it up and release clutch quickly). make sure you release the clutch quickly and don't slip it. Some people swear it works better the other way but it's hard to do it by feeding in a little gas with a Challenge clutch. Most people that do it this way end up riding or slipping the clutch pedal and this wears the clutch out. As for heel n' toe just make sure you match revs and be smooth. Just like the RX7 no different at all. This was at one time my biggest weakness and getting it right saved a lot of clutch $$$'s. Jon | ||
| Rob Lay (Rob328gts)
Board Administrator Username: Rob328gts Post Number: 3709 Registered: 12-2000 |
What is the proper way to save the clutch in regards to 1st gear starts and heel toe? Is it better to just gas enough to get the car rolling and then engage the clutch fully or is it better to gas it up a little more and engage the clutch quickly? For proper heel toe do you just need to make sure the revs are matched properly before engaging the clutch? | ||
| Jon P. Kofod (95f355c)
Member Username: 95f355c Post Number: 465 Registered: 8-2001 |
Dennis, Clutches don't last because folks don't know how to use them properly. Jim Kenton, who raced a 355C and a 360C at FOW got an entire season out of a Challenge clutch. He's not a backmarker but a front runner who finished second a few years back in the series. Two things more than anything wear out a Challenge clutch. Improper heel n'toe and driving the car in and out of a trailer in 1st gear. I never drive the car out of the trailer and am in the process of installing a winch to pull my cars in the trailer. I hear Challenge owners "slipping" their clutch all the time when they pull the car out of the trailer or line up on the grid. This is where all the wear comes from. Getting a 355C down to 2900 involves removing windows, headlights, AC and other items. The interior only removes about 100-150 pounds which gets you down to to about 3050 or so. Thrown in the carbon fiber front bumper and this gets you down to about 3000. My Challenge car weighed in at 2948 recently and about the only thing not removed on my car is the glass and the AC. Rob S. is also correct about extra power being negated by proper race rubber. Take a look below of my video chasing Allie Ash's F40 at Summit Point. Allie is clearly a better driver than I am having competed in the Challenge Series and Historic Series for over 10 years. His car has been dynoed at 502 hp. My 355C with race rubber is a faster car even with a slower driver/racer and a bad shift between turns 2 and 3. http://www.ferrarichat.com/discus/videos/jon355c/Video5M.mpg You will see that anywhere he can get the car straight he leaves me in the dust but under braking an in turns I eat him alive. His fastest lap time at Summit in the F40 is a 1:23. My fastest lap is a 1:19 and I can consistently rattle off 1:20's all day long. Good race rubber and superior brakes will beat hp anytime. While I wouldn't call the underbody diffusers or the front carbon fiber bumper, maintenance issues/costs you will go off the track if you run the car properly and these two items are very expensive and near impossible to find. You can get aftermarket lightweight bumpers but the underbody panels are near impossibly to find except off of wrecked cars. For a while FOW told me that Ferrari was making carbon fiber underbody panels that were something like 8K. And heaven forbid you need a new factory rear wing. Providing they have one (last count they had one left) you could pay anywhere from 8-10K from FNA. Aftermarket replica wings can be had for 3-4K. Regards, Jon P. Kofod 1995 F355 Challenge #23 | ||
| Rob Lay (Rob328gts)
Board Administrator Username: Rob328gts Post Number: 3708 Registered: 12-2000 |
Great information Dennis, this is the stuff I'm looking for. | ||
| Kevin Marcus (Rumordude)
Junior Member Username: Rumordude Post Number: 123 Registered: 9-2001 |
dennis -- your note almost perfectly reflect my experience over the past two years w/my '98 f355c, except that I am getting a new tranny this time as well. There is a ton of "unnecessary" weight on the cars. Ever swing one of those doors? Woah! | ||
| Dennis (Bighead)
New member Username: Bighead Post Number: 13 Registered: 2-2003 |
Rob, a few points of data: Weight totally varies from car to car, as owners stripped the cars to different degrees. A few Challenge cars were never raced, and are essentially street cars with Challenge parts added but nothing removed. My mechanic has a 355CH he bought in Germany that was never raced... it's a full CH, but it also has A/C, full interior, etc. As these cars move to Driver's Ed use, the variations increase. If you take a typical 355 CH, and strip out much of the interior but don't do stuff like change body panels to CF or fiberglass, you'll end up somewhere around 2900lbs. (don't forget, that roll cage is not light). Prices today vary from $65k to $100k depending on mileage, condition and spares packages. Nearly every 355CH for sale today has had accident damage; the Challenge series wasn't so different from NASCAR. Some have been totally bent; others only have panel replacements. What do you expect? It's a used racecar! 1995 models were converted from street cars; 1996+ models were imported as race cars only, with no titles (I believe) and much of the equipment already installed. Maintenance does vary from car to car. Clutches don't last long (ever taken a look at a Challenge clutch?); brakes are huge and not cheap. Must use Speedline Magnesium Challenge wheels, as stock wheels will not fit over Brembos. Pirelli Slicks are awesome, worth lots of seconds per lap, but don't last long and are $400+ per. Most 355CH, like stock 355s, have oil and water temp gauges, as well as oil pressure. No Fuel pressure or transmission temp gauge, unless you add. Transmission is pretty bulletproof. Brakes are incredible, but new rotors (and hats and fasteners and pads) are $$$, as are clutches and tires (see above). Engines are generally reliable, but have the same problems as street 355s and should be upgraded/upgraded in the same manner. Hope this was helpful. vty, --Dennis | ||
| Rob Lay (Rob328gts)
Board Administrator Username: Rob328gts Post Number: 3706 Registered: 12-2000 |
Let me get this back top as I know there must be more info than this. Thanks. Since there really aren't any engine mods, it appears the engine would be about as reliable as street 355's. However, I think the infrequency of use, but then the intensity at those few times might create greater wear. What temps should you keep it within? Do they have oil and water temp gages? Would a trans temp guage be of benefit? How about oil pressure? Fuel pressure? Sorry for all the questions, I'm just in one of my modes to learn everything I can. | ||
| Martin - Cavallino Motors (Miami348ts)
Advanced Member Username: Miami348ts Post Number: 3874 Registered: 5-2001 |
Martin in his 348TS: 10:04:23 | ||
| Rob Schermerhorn (Rexrcr)
Member Username: Rexrcr Post Number: 263 Registered: 11-2002 |
As for maintenance, this can be a very cost effective chassis to maintain. The major components last a long time with little maintenance. Other than the obvious nut and bolt checks, alignment checks, cleaning and fluid changes, it's a clutch disc every couple thousand race miles if you want to be conservative, or carry a spare and see how long it will last with your driving style as it's not difficult to change at the track. Other than that just brake system maintenance and cosmetics / undertrays, and tires. If you don't stuff it, it may be as expensive as your Spec7, until you must rebuild a major system, which could be year(s). | ||
| Rob Schermerhorn (Rexrcr)
Member Username: Rexrcr Post Number: 262 Registered: 11-2002 |
Regarding the lap times posted: One of the most difficult comparisons to make is ultimate lap time, one car vs. another. There are so many variables, one can only look at this data and make generalities with little conclusions. So, IMHO, with my experience with racing Ferrari road and race cars, looking at this data, the reason for the difference in lap times has much to do with the rubber each car was wearing. The Challenge and GT cars are race cars and therefore I can assume used slicks. For point of reference, a F355 Challenge on a 1.7 mile road race course, Pirelli slicks vs. Hoosier "DOT approved" race rubber, the difference was an amazing 5 seconds per lap, same car, same driver, similar weather and track conditions. Now compare an F40 on 1990 era PZero's vs 360 GT on 2001 race slicks: the power difference cannot make up for improved handling dynamics and vastly better grip. I regularly saw 1.4 g lateral on 360 Challenge data, a stock F40 on a good day with a great driver will pull 1.0 g lateral. It's weight, chassis dynamics and differences in the tires that make the differences in lap times without picking too many nits. Ps. RobL, I have much F355 Challenge info that when I have time can compile including set-up sheets and a pristine copy of Introduction to the Vehicle Dynamics by Albergucci and Battistini, published by Ferrari, SpA and utilized at their F355 Challenge training course for technicians participating in the Challenge series. | ||
| BJ (Bjkim)
Junior Member Username: Bjkim Post Number: 52 Registered: 10-2002 |
why those super super Ferraris and V12 super Ferrari are slower than little V8 Ferraris? Are those numbers made by same drivers? | ||
| Rob Lay (Rob328gts)
Board Administrator Username: Rob328gts Post Number: 3689 Registered: 12-2000 |
Just want to start a thread to gather all the info we can. Stats 380 HP Fiorano Lap Times Ferrari F2002 - 0.58.378 Ferrari 360 Challenge - 1.22.4 Ferrari 360 N-GT - 1.18.9 Ferrari 355 Challenge - 1.26.5 Ferrari F50 - 1.27 Ferrari F40 - 1.30 Ferrari 550 Maranello - 1.32.528 Ferrari 575M Maranello - 1.31.512 I know I don't have much info yet, but wanted to start somewhere. What is the weight? What are the price ranges? How many are there? Typical maintenance from owners? Links to sites with good info? Thanks, rob |