Slicks on a 430 Scuderia

The electronics can be disabled through the manetino.

 

what about the E-diff?

 

slicks cannot be applied to the scuderia. even with the cst off setting, over 160km/hr you still have some electronic intervention. also the lateral accelerometer cannot handle the excessive force applied by cornering with slicks. i asked the same question as i wanted to have a dream race of a scud with slicks against a challenge car. still want to see it one day i guess.

 

track car that can't handle slicks ??? go figure......

 

I assume you mean scuderia = track car?

Ferraris arent really set up for the track. Yes of course a Stradale and I assume a Scuderia both perform wonderfully on the track. But they are still just street cars..not track cars. Cars like the Stradale & Scuderia are set up for highway driving, parking lots & stop lights. Both these cars as well as all other Ferraris are set up to have a softer ride & understeer than true track/race cars. Electronics now too it seems (based on the poster above) has now too be changed to the point where it cant handle slicks. Owell. It's a shame.

 

well, GT2's and GT3's certainly have no issues with slicks.....

 

I took a Porsche of mine and added slicks too. When I added slicks to a stock suspension, the slicks over worked the suspension & I could fully compress the stock springs due to the extra grip. I added Carrera Cup sway bars, shocks & 2 part springs. Car was great fun on the track!

 

Just back from Fiorano with some of the guys that helped design the 430 challenge. The above post is correct. No clicks can be applied to any car with the 430 electronics. It has to do with the Breaking system most importantly. The breaks simply won't work correctly.
The 430 challenge therefore uses the 360's electronics. BTW...the challenge is a beast! I've never experienced breaking like that.

 

Now that the Scuderia has been out for a while, has anyone mounted slicks. Can you explain how to modify the electronics?

 

many people run with slicks on new gt3 without problems. it has abs, tc, lsd but no stab control or electronic diff. gt2 and the new 7.2gt3 do have stab cont so wonder if slicks no good for them either. is my gt3 the last of a breed that can use slicks?

what about the hoosier tires that look like slicks but are supposedly allowed on street. can they work with new electronic systems?

 

No need to modify the electronics.

With CST-OFF and CT-OFF, the e-diff is disabled, it actually locks at maximum level, but the ABS and EBD are still active. It very easy to get the tail out of control with CST/CT OFF. In Race mode the e-diff applies more torque to the inside rear wheel, and the car pushes a lot more, I think the system is very intrusive, yes it keeps the car under control but the car moves away from the apex. I tried the Race mode with A6 and stock tires.

The problem with slicks, Kumho V710 and Hoosier A6 (these two tires have better grip than most slicks) and the Scuderia is the same problem found with the 997 GT3 RS , 996 GT3, Viper, Lotus, Corvette, Lambo, etc. All these street cars have suspensions calibrated for street tires, and ABS calibrated for that level of grip.

The Scuderia on the stock tires works quite well, but on Hoosier A6 it moves a lot. The A6 was 5+ secs faster on a 60 secs course compared to the stock Corsa r-comp tires. I don't consider the Michelin Sport Cups, R888, RA-1, Corsa to be sticky tires, they're better than street tires, but still far away from the grip provided by medium and soft slicks, the Kumho V710 and the Hoosier A6.

During braking on A6, the front end dives a lot, I measured around 1.5" of suspension travel, given the stock spring rates, this in an extra 1400 lbs coming to the front end, the rear gets very light, the EBD( which only job is to apply rear brakes left and right to keep the car straight under braking) gets to work, the lack of rear grip makes the EBD to lock the rear wheels, this kicks in the ABS rear left and rear right and gets to ice mode (safe mode) due to not being able to slow down the car at the threshold of ABS, the car washes out and won't stop. Scary? probably, unless you know what to do.

I experienced the same problems with the 996 GT3 and 997 GT3 RS, but the problem was worse with the 997. Most people don't know whether the TC-OFF for the 997 GT3 RS disables the EBD, but the braking behavior with slicks and A6 makes me wonder that EBD may still be active even though TC is off.

With the 997 GT3 RS I changed the suspension to make it stiffer, and using a different braking approach (progressive rather than abrupt braking) I could get the car to work well on slicks. I applied this same technique with the Scuderia and was able to brake quite well, if my memory serves me right, the braking power in the Scuderia works better than my GT3 RS with 350mm/350mm Gen I PCCB and track pads.

The Scuderia really needs stiffer springs to run on sticky tires. I will be testing a new set of springs and new shocks as a consequence of running different springs. This will reduce the body movement, and keep the tires on the ground with enough weight to have grip, reducing the intervention of EBD and ABS, and producing faster lap times.

The Scuderia cannot use 18" wheels, so that limits the available slicks to Michelin and Pirelli, both skinny and on intermediate compound, so these tires should be slower than the A6 on wide sizes.

 

Wow very interesting thread and a real shame that electronic babysitters can't be turned off enough to race the car to the potential as is. This really lowers the car's potential until you strip electronics and start modifying which is its own can of worms. That right there is enough to prevent me from buying one.

For me progressive braking always worked better and slowed down the weight transfer which causes rear end wiggle. I found the lowly 348 racecar worked very well with ridiculously stiff front springs which also resisted dive helping braking alot. I am so thankful to be T1 racing a Z06 now where I can turn all the junk off except the ABS.

ABS in all cars on slicks or DOT race tires has never been an issue for me and I don't think it is an issue at all in the sense that the ABS is not set of street tires vs race tires. The ABS does not know. It only senses slip. So the ABS threshold on streets is lower than on race tires but to ABS it is the same. So IMO ABS will give you max -G which is tire specific not ABS setting specific. The real problem with ABS is that if you spin both feet in just does not work as well as it does on a non-ABS car. That's about the only ABS fault I can think of.

 

Scud can run with slicks, guy down here raced his car at Kyalami with slicks and had no problem, let me tell you he was going much faster than 160 km/h...I have also been in the car around the track on slicks and there were no problems at all.

So where all these stories about electronics come from I really dont know...

 

Scud with slicks on
http://img.photobucket.com/albums/v59/Ferrari360/Cars/IMG_0283.jpg
http://img.photobucket.com/albums/v59/Ferrari360/Cars/IMG_0036-3.jpg

 

I agree with your statement that the Scuderia does not need any modifications to run stickier tires. I think this is true for the most part.

What I don't agree with are you statements on the tires you ran comparing them to slicks. The Hoosiers A6, Hoosier R6, Kuhmo V710, Toyo R888, Michelin Pilot Sport Cups, Pirelli Corsa, and Hancook Z214 are all R-compound tires. These are DOT legal sticky tires that are more suitable to running on the track. These tires are DOT compliant because they come with a minimum amount of tread or grooves in them. Most of them only work well when they are shaved or at a point of having 4/32nds of tread. They are not true slicks. A true slick is offered by Michelin (most fast ALMS teams run Michelins), Dunlop, Yokahama, and some other manufacturers. These
tires are not DOT legal, they are offered in different compounds, the sizes are measured with a different system, and have a lot stiffer sidewall than the DOT R-compound tires.

As far as suspension goes on the cars, a DOT-R tire can work with the stock suspension and electronics. The issues that come up when running a DOT-R on a street car with TC (Traction Control of some kind) and ABS is caused by the extra grip the softer compound of the DOT-R creates. With the new cars using a G-sensor (accelerometer) to help aid in some of the TC systems the ECUs will only allow so much grip with the cars. If this level is exceeded under braking or corning then the computer will take over. This can cause the ABS to operate or cause the TC to kick in during the middle of a turn. This happening does not allows mean the car is losing grip or spinning the tires with these extra sticky DOT-R tires. There can still be grip available but the computer won't let you use it based on its calculations. Turn the TC system off and then feel out the grip to find out how much there really is.

Now a true slick will offer more grip but our cars with stock suspension and stock brakes will never come close to maximizing the grip these tires offer. Our cars whether a stock Scuderia, F430, 360 CS or 360 are not truly setup to run slicks. The sidewall is too stiff and we have too light of a spring in the car. This is when the electronics will more than likely need to be updated or the suspension upgraded to handle these tires. Does this mean don't try to run slicks on the car? No way you can still do it and the car will be faster than with DOT-R tires. The ABS will still work with the car. Everything will be faster with these but the car will probably not feel as good with these tires because the inadequacies of the suspension will start shining.

Also you statement about an extra 1400lbs coming to the front of the car during braking with R-comps has nothing to do with the tires. The weight transfer to the front of the car stays a constant no matter if the spring rates, shocks or tires are changed. The only thing that will change the amount of weight transfer forward is if the car's weight is changed or if the front/rear weight bias is changed. All that changing springs, shocks, or tires will do is to change the rate the weight will be moved onto the front end. The same goes for cornering or acceleration forces if the weight and bias of the car remain a constant.

 

Seth,

I have used the Traqmate to measure grip levels from a variety of tires. I put the Hoosier A6 and Kumho V710 on a different class compared to all the other DOT R-comps, and these two tires offer more grip than plenty of slicks on medium and hard compound.

Unfortunately, for track use these two tires exceed their operating temperature after the 2nd/3rd lap (depending on track length), so their grip decreases but they're still fast beyond the ideal temperatures. On their ideal operating temperature (130-150 degrees F), the A6/V710 exceed the grip of most slicks.

It's only when you get to medium-soft and soft slicks where you find more grip than A6/V710 (at their operating temperature). The exception being the Michelin Blue Cup that on a medium compound has proven me 0.1 higher g-forces at a road course compared to the A6. Everything else I have tested through the years, Yokos, GY Radial(250 compound), Pirelli D5/D7, Dunlops have produced lower grip levels than A6.

The A6 and V710 have two grooves of 10mm wide each. So a 305mm A6 is equivalent to a 270 slick (remember that slicks don't require a round shoulder by the DOT). To generate the grip level found in 21/27 Michelin slicks for the Ferrari Challenge, you need 245/305 slicks, and compared to the Pirelli slicks (235/295), you need 275/335 A6.

For the Scuderia, we're limited to Michelin in s8/s9 compound F/R (the higher number means the harder compound) and Pirelli Ferrari Challenge spec tires in medium compound. Not possible to run 18" wheels on the stock brakes.

The stiff sidewalls on slicks don't determine their grip, it's their compound and construction. The tire sidewalls are part of the suspension, so matching spring/shocks/anti-sways are required for a given tire. For the stiffer sidewalls slicks, ideally we need stiffer suspension. The sidewalls on the V710/A6 are very stiff, but not as stiff as the slicks.

I'll be testing the Pirelli FC slicks against the A6 once my third set of wheels shows up, but I doubt they will be capable to match the grip of the A6.

I didn't explain myself well on the weight transfer stuff (1400#). What I wanted to mention is that with the extra grip on the A6, the car dives a lot, weight transfer stays the same, but weight distribution given the excessive rake caused by the soft front springs makes the rear even lighter and more prone for the EBD to get to work. This is something that can be fixed with stiffer springs, and matching shocks.

These are the stock spring rates and alignment from the Scuderia. My car alignment came way out of shape (typical on new cars), but the cross weight came pretty good.

Front: 475# Linear. Camber -1.5 degrees, Toe-In 1.25mm per side (2.5mm total), Ride height 114mm
Rear: 650# Linear. Camber -2.0 degrees, Toe-In 2mm per side (4mm total), Ride height 136mm

I'm using different alignment specs and ride height.

 

Good conversation! I would love to see some of the Traqmate data on this. Honestly I have never seen this kind of results with a DOT-R compared to a true Slick.

The temperatures you listed will not achievable on a road course. In less than 1 lap the tires will be at these temperatures on most courses with a car weighing over 3000lbs. And with the A6 as you mentioned it will not hold together or last much longer than that 1 lap. After it gets over heated its grip level will drop off significantly. There is no way an A6 will last a full 20-30 minute session on track.

Also the grooves in the tires does not effect what size slick it compares to. The overall width of the tire is the overall width of the tire grooves or not. A 270 slick does not compare to a 305 DOT-R because of grooves in the DOT-R. It has to do with the overall width measurements of the tire only. Your statement: "To generate the grip level found in 21/27 Michelin slicks for the Ferrari Challenge, you need 245/305 slicks, and compared to the Pirelli slicks (235/295), you need 275/335 A6." is very misleading. The grip level of a tire is not determined by its size as there are a lot more factors that go into it.

And if you are still finding the A6 as the tire that generates the most Gs that can be misleading. Does the A6 give you the fastest lap times? What tire gives you the fastest lap times?

And you can't call the A6 or the V710 a slick. They are a DOT R-Compound tire. There is a big difference in a R-compound tire and a true Racing Radial Slick tire. They are not even close to being the same.

 

I have plenty of .tqm files. Fast tires on the left, slow tires on the right. Notice the higher g-forces generated by the A6. Also, consider that the Michelin Blue Cup series tire is a Sprint race slick, and proven to be one of the fastest slicks out there for cars around 3,000 lbs. Yokos, Dunlops and GY on 18" are slower. These are graphs generated from the GT3 RS.

Michelin Sport Cups vs. Michelin Blue Cup slicks at CalSpeedway (AAA Speedway)
http://members.rennlist.org/nj_gt/2009-02-MPSC-MPSX-CalSpeedway.JPG


Michelin Sport Cups vs. Michelin Blue Cup slicks at Streets of Willow (AAA Speedway)
http://members.rennlist.org/nj_gt/2009-02-MPSC-MPSX-SOW.jpg


Michelin Sport Cups vs. Hoosier A6 at PCA AutoX El Toro Airport
http://members.rennlist.org/nj_gt/2009-02-MPSC-A6-PCA-AutoX.JPG

This is some information from these three events, plus another two on A6 and slicks where I did not gather Traqmate data. The Cal Speedway video at http://www.vimeo.com/Porsche, the other four events posted in the POC/PCA web sites.


"Time Difference" / "Prorated Time Difference on a 60 secs course" / "Observations"
PCA AutoX 11/09/2008
Michelin Blue Cups (3 laps 1 HC) 240/270 70.100
Michelin Sport Cups (8 laps 1 HC) 265/325 73.900 3.800 3.085

Cal Speedway 11/23/2008
Michelin Blue Cups (12 lap and 3 HC) 240/270 107.830 205 degrees
Michelin Sport Cups (12 lap and 3 HC) 265/325 112.787 4.957 2.637

PCA AutoX 12/08/2009
Hoosier A6 (8 laps 2 HC) 265/345 83.200 over heated A6 at 160 degrees
Michelin Sport Cups (24 laps and 5 HC) 265/325 87.500 4.300 2.949

PCA AutoX 01/24/2009
Hoosier A6 (11 laps 3 HC) 265/345 69.110
Michelin Sport Cups (32 laps and 7 HC) 265/325 73.420 4.310 3.522

Streets of Willow - 01/25/2009
Michelin Blue Cups (25 laps and 4 HC) 240/270 84.096 190 degrees
Michelin Sport Cups (32 laps and 7 HC) 265/325 88.418 4.322 2.933

At SCCA Solo and ProSolo National level, drivers are debating and testing A6 against the traditional soft compound slicks (GY 160/250, Hoosier R25B). These slicks are even softer than the ones used for Club/Pro Racing on heavy cars, drivers are getting mixed results. I'm consistently faster on A6 compared to any slicks tested to date, except a brand new set of Michelin Blue Cups that did great, where an A6 would have overheated due to the high temperatures that day.

The A6 overheats quite easily, that's why it's not popular for Road Racing, but if you check on the SCCA regional series, some drivers are using A6 to qualify and jump to the front in tight courses where passing is difficult, they're even racing on them, because when overheated they're a few tenths slower than R6, very challenging to make a pass with such difference on a tight racetrack.

I actually used the A6 for Time Trials. At one time I ran them in my 2004 GT3 and I was around 2 secs slower than the National PCA Club Racing record at that track, set by a GT1-R car on slicks. At the same time trials, my street car on A6 ran faster lap times than all the race cars on slicks. The A6 is good for 2-3 laps.

On the very specific details about comparing tires, you're right, too many factors to consider. The two small groves on both V710 and A6 reduce the actual contact patch by 20mm. I measure all my tires for actual width mounted on the wheels and ground contact patch. I always get specs different to the tire manufacturer, but ultimately this will let me determine what sizes fit in the car. The contact patch from a 270 Michelin slick matches the contact patch from a 285 Hoosier A6, but the A6 still has those 20mm on channels (for DOT certification), so a 305 A6 puts around the same contact patch width to the ground, the contact patch area will depend on tire construction and diameter, assuming same car.

The A6 is not a slick, is a tire with more grip than plenty of slicks. Just take your car to a local road course, heat up the slicks for three laps and run one hot lap, switch to A6 and run two more laps, compare results. At SCCA National level AutoX and ProSolo the A6 and V710 are the choice of tires, with very close results on the stock classes (I prefer the A6).

My F430 is working quite well with grip levels higher than most slicks, it could work even better with some suspension work, but there is no need to alter anything else, unless you really want to increase the performance (headers, ECU mapping, FIA GT3 cams, stronger differential and axles,etc). By the way, the time difference between the Pirelli Corsa stock tires (DOT-R compound tire) and 235/315 A6 (another DOT-R, not a slick) was over 5 secs on a 59 secs course. This is the most impressive time difference I have seen comparing two DOT-R tires. The funny part is that every test that has been done with the Scuderia involves these crappy tires, tires that are close to 2 secs slower on a 60 secs course than the MPSC used in my GT3 RS and the new Viper ACR.

 

I have to agree with Rad too in reality but agree with Seth in concept. The slick is supposed to be the stickiest. But in reality slicks are made more for purpose. For example you can't find yoko slicks that will work front and rear for 355C wheels and you can't find goodyears that will work at all. This is because slicks are made often for specific venues and specific car rules. Also, while a slick could be made very sticky often they are not. For example the granAm slick from hoosier was actually less sticky that the hoosier dor R S05 of it's day. So while you can say an A6 is sticker than a R6 etc it is very hard to say a slick is sticker than a DOT R.

 

Sorry again but I agree with RAD. The fastest guys in SCCA T1 running 3000lb+ vettes are all running A6 for the race then using the tires for practice until corded. So they work just fine eventhough they are an Auto-x tire.

I'm running them in T1 right now at 3200lbs.
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Excellent thread with meaningfull info!!

 

nice work my friend, but you should get one of these instead....
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Really strange opinion. Seems that you haven't been to factory nor any race Ferrari taking a part. Shame...

 

Once again the Scud can be fitted with slicks and driven hard with no problems at all.