| Author | Message | ||
| Jon P. Kofod (95f355c)
Member Username: 95f355c Post Number: 674 Registered: 8-2001 |
Rob, Sorry I am late to the post but it looks like Rob S. and the rest have you pretty well covered. A few things I might add: Brake Pads: Pagid Orange's offer a softer bite (lower torque) and are much easier on your rotors than the Performance Friction pads that use (PF97 and PF93). You will notice a big difference between the PF and Pagid pads but you will also go through rotors at twice the rate with PF pads. PF pads also take much longer to get heat in them. On cold days I have to tape up the brake duct holes to generate enough heat. I think Rob is correct about running the slotted rotors at anything other than the Run Offs. Most will not know the difference. DOT vs. Slicks: Pirelli PZeros seem to last a few heat cycles longer than a Hoosier R tire. But not by much. Part of the reason is the lightweight fiberglass belt construction of the Hoosier. The PZero offers way more grip than the Hoosier. In terms of last neither will last more than 8-10 heat cyles before they lose most of their grip. The tires themselves will still hjave plenty of depth left but the grip will be gone. I know some folks who don't push them too hard can get two weekends out of them but knowing how you drive the RX7 I can guess you will get one good day and half out of them and spend the second half of the second day working on car control. I have never used Kuhmos, Toyos or other R compounds on my 355C but while you may get them to last longer their grip would be horrible compared to a slick. Ferraris official stance on the tire pressure was 22-23 cold (can't remember the exact pressure front and rear but I use 23 1/2 front 24 rear). There are varying reports about what they should be hot but the best advice I got was from Tony at Algar who told me no more than 31 1/2 front and 32 1/2 rear. Seems to work best for me at the tracks I run but it will take your seat of the pants feel and a tire pyrometer to see what works best for your driving style. In addtion to PZeros which can only be sourced new I get used Dunlop Grand Am tires which are not quite as good. A little bit less grip and the tire pressures will drive you crazy (adjusting them). If you run the car anything over 45 minutes at a time on the Dunlops they go to hell in handbasket. Seems the tires get overheated no matter what tire temp you are running and lose significant grip. If you come in and cool them down for a while and then go back out the grip comes back. Unfortuentally these are the same Dunlops that Cort Wagner and Bill Auberlin complained about on their 360GT last season. They kept tearing the tread off them. Keep in mind none of us will run that hard for that long but again 45 minutes seems max for the Dunlops. Bars and packers: Go with a base setup and then get comfortable with the car and your driving style. Use the bars to fine tune things alond with the bump stops. At Summit Point is use both large bars, but at the Glen I only use the large bar in front. I pretty much leave the bump stops the same though technically you would soften things up for the Glen if you were racing. The 355 C can be nicely setup for some corner exit oversteer and it is quite manageable. My car will step out a bit as I hit the apex (or slightly past the apex) in turn 10 at Summit onto the main straight. Gets rid of all understeer which the rear wing generates in it's full downforce configuratiuon at Summit. At the Glen I take a bit of wing out but not much. Wing: Ditto everything Mitch said. I wouldn't worry to much about the wing the first few times. I was told to keep it at ful downforce then set the suspension up and get comfortable with that first. Keep in mind that when I did this I had a lot less experience than I do now and was much slower. I am not sure three years ago the wing adjustments would have made much difference to my lap times or to my seat of the pants feel. Nowadays the wing adjustment can make the 355 seem like a differnt car at Summit when not set up properly. Most will tell you to do the wing and suspension at the same time if you can drive the car pretty much flat out at the limit and can feel all the adjustments working (or not working). Check your email in the moring for my source on used tires. It's on my work computer. Regards, Jon P. Kofod 1995 F355 Challenge #23 Website: http://neverlift.homestead.com/flatout.html | ||
| Mitch Alsup (Mitch_alsup)
Member Username: Mitch_alsup Post Number: 690 Registered: 4-2002 |
Packers are the little bump stops on the top end of the shock rod. Leave these until the car is basically dialed in and then adjust them for that last iota of predictability. 1) Sway bars are used to set the low speed oversteer/understeer characteristics of the chassis. Adding more stiffness up front induces understeer as more weight is transfered from the inside front to the outside front tire. To a certain extent, you can fine tune this with tire pressures (or rake) once you are in the right ball park with the springs and ARBs. 2) the proper way to set the rear wing is with a stop watch! The wing increases downforce quadradically with speed (in free air: which never happens around race cars) so use this to fine turn the oversteer/understeer relationship at high speed (corners), and use the springs, ARBs, and tire pressures to fine tune the O/U relationship at lower speed (corners). When the car feels good at the lowest speed corner and the high speed corners, you are set to fly. 3) get a pyrometer, and start taking notes. 3.a) take 3 reading across the face of each tire immediately after a hot lap (in hot pit if possible, by assistant if possible) 3.b) Tire temperature tells how much work that part of the contact patch is doing. In theory you want an even profile, however, in practice, the outside edge get better cooling than the inside edge (full bodied ars); and tires on the predominant side of the car are often 10-30 degrees hotter than tires on the less dominant side. 3.c) desired readings: outside edge 10-20 degrees cooler than inside edge, center average of inside and outside. 3.d) Camber: Inside too hot->less camber; outside too hot->more camber 3.e) Pressure: center low->more pressure; center high->less pressure 3.f) toe: don't remember how to set this with pyrometer When I started to get my car setup, it was an oversteering mother. The rears would read 50 degrees hotter than the fronts. After finding the issue and dialing the car in, I am now running within 10 degrees front/rear and within 10 degrees side-to-side. It is now a completely trustable car with great grip, easy smooth driving style, and provides emense amounts of driver feedback. | ||
| Rob Schermerhorn (Rexrcr)
Member Username: Rexrcr Post Number: 616 Registered: 11-2002 |
Packers are washers made of plastic, specifically UHMW polyurethane, in thicknesses of 2, 3, 6 mm. Placed on the shock rod between the bump rubber and the top of the damper body, it's used to "tune" when and how the bump rubber comes into play, adding roll resistance, effectivly moving the relative front-rear roll balance. I do this before damper tuning, after choosing springs and anti-roll bars for the track. The car will be sensitive to a 1 mm change when you get close. Beacon refers to the timing light (laser actually, of a specific frequency) used to place a timing mark in the data stream of the logger. What system do you have? Marelli? Pi? This is a very powerful tool and a big extra added to your car. Learn to use it. I can teach you (hint). | ||
| Rob Lay (Rob328gts)
Board Administrator Username: Rob328gts Post Number: 5041 Registered: 12-2000 |
What are packers? I'll read through all your stuff before I ask anymore. Sorry about that, I'm not being a very good FC user right now. I'm just excited I have the car in my possession as of today. Last night when we started it up the computer came on and at least the RPM's were working after we flipped the switch. So I can get the software from Beacon? Do the rear end and trans have the same fluid reservoir? | ||
| Rob Schermerhorn (Rexrcr)
Member Username: Rexrcr Post Number: 615 Registered: 11-2002 |
In all fairness, to expand on question 1: Yes, they do make a difference, you will feel it. Run the big front bar, period. As for rear, you can experiment, but I recommend the larger. Packers are an excellent fine tuning tool, as is manually adjusting the dampers, which I've also covered. | ||
| Rob Schermerhorn (Rexrcr)
Member Username: Rexrcr Post Number: 614 Registered: 11-2002 |
You havn't, but I've posted this already...which is why I spent some time compiling the info I've posted in the past, but not this stuff yet. 1.http://www.ferrarichat.com/discus/messages/251280/210368.html 2.http://www.ferrarichat.com/discus/messages/251280/210368.html 3.http://www.ferrarichat.com/discus/messages/251280/210368.html Hope this helps.  ps, yes, all your questions are answered in that thread, and more. As for specifics on dialing in race slicks, it's temps, pressures, stopwatch, and the all important a$$-o-meter. pps, did you get the data acquisition sytem running? Software to drive it? Beacon? | ||
| Dave (Maranelloman)
Intermediate Member Username: Maranelloman Post Number: 1727 Registered: 1-2002 |
Rob, you might also want to call David Moore about this as well... | ||
| Rob Lay (Rob328gts)
Board Administrator Username: Rob328gts Post Number: 5040 Registered: 12-2000 |
Ok, here's some questions I know I haven't asked before... 1) They gave me some sway bars with the car. How big of a difference would that really make? I don't think much. 2) How much do you adjust the rear spoiler? Full down force at tight tracks and least angle for rovals? 3) Any idea where I should start from with cold tire pressures? Both the PZero slicks and DOT R's. | ||
| Rob Schermerhorn (Rexrcr)
Member Username: Rexrcr Post Number: 611 Registered: 11-2002 |
Shouldn't this be in Tech?? OT flag? | ||
| Rob Schermerhorn (Rexrcr)
Member Username: Rexrcr Post Number: 610 Registered: 11-2002 |
Rob, if you're running T1, you need the DOT's (I know you know this) and the rule is +/- 20 mm on section width over OEM. So you can run 295 rears, and what? 275 fronts?? Rotors? Technically, you must run the drilled Brembos according to Challenge regulations homologated into SCCA Touring regs. But, IMO / IME, run the slotted only rotors from Brembo, they'll last longer and unless you're going to the Runoffs, no one will know they're technically wrong. I do like cryogenic treatments if you have time. Order spare rotor to hat mount fasteners for spares (guarenteed to break one if you have no spares). Use a torque wrench when installing these small fasteners. I replaced the nuts once per season to avoid heat cycle fatigue. Pads, check the archives, do a search! JK Pagid is OEM, I like 'em. Performance Friction has some of the best performing friction material available, and new compounds I havn't run yet; they'll fit, too. Ferodo is worth considering, performance is good, too. These are the only ones I'd consider (my opinion), but other's are likely to be as good, and one will only know with scientific testing. Brake fluid!@#$, you already know my recommendations, you posted in those threads: Ford HD for ROI, Castrol SRF for ultimate performance. Order new caliper seals now while you have time and plan on rebuilding them AT LEAST once per season. I did it every three weekends, and alway before Montreal (hardest on brakes). | ||
| Jason Williams (Pristines4)
Member Username: Pristines4 Post Number: 323 Registered: 12-2002 |
www.Carobu.com I'm a dealer for them, so if you want their pads shoot me an email. Jason- | ||
| Rob Lay (Rob328gts)
Board Administrator Username: Rob328gts Post Number: 5036 Registered: 12-2000 |
I need to buy some tires, pads, and rotors. Does someone have access to a SCCA GCR and tell me the F & R tire sizes, mine is at home. Also, what are the contacts again for used race tires (Slicks or DOT)? Looking through our thread on this before Jon mentioned Slicks last longer than the DOT tires? Is that true? How many heat cycles can you expect from each one? Also, what pads and rotors do you recomend and where can I buy them? I want the best deal, if they're still quality. What brake fluid would you recomend? |