Gen 2 track thoughts

[serafins]

My thoughts after running my gen 2 acr at the track for the first time at Waterford Hills.

Tires: The continental extreme contact tires that are becoming real popular for the 18" wheels **** when they get hot. They are a great street tire and hold up for maybe 2 laps at speed. Then they turn to mush and start screaming instead of gripping. The Michelin's were no better - I ran with another viper who had Michelin's on 17s and his tires looked worse. I will say that I never, ever felt like the rear end was going to step out on me. I attribute that mainly to the suspension though.

Brakes: I have the stop tech 4 wheel BBK kit. I was running street pads (DFC street +). They stayed perfectly cool and I did not have any braking issues. Could very easily lock up the tires at any speed. Frankly I need a lower friction pad until I get a set of slicks. The tires were clearly the limiter. I actually ran off the track once when the tires started getting really squirrely when braking.

Cooling: I have a huge aftermarket aluminum radiator, never got above the mark to the right of 190*. Clutch was another story. Even though I replaced the clutch and brake fluid with RBF 600, the clutch fluid boiled repeatedly. Very annoying. Bought a ton of heatshield wrap to wrap the line in to hopefully stop this. If anyone has solved this issue feedback would be appreciated.

Power: Car could always use more power, but it was not an issue at Waterford hills which is a short track. The fastest I hit on the back straight was 101 with the recorded going. The fastest cars out there run about 110-115 or so. And I was not dogging it that time, just stayed in third gear and only rev'd out to 4500 before letting off out of noise concerns. Really could use more rpm though which I will be talking to Prefix about. They previously moved by rev limiter down to 5900 from 6400. It needs to go back up to 6250 or so. This would allow me to avoid a gear shift on the back straight (once I get a quieter exhaust that will let me rev it out without getting noise flagged).

Suspension: Stock rebuilt '99 ACR suspension was great. Set the shocks at 2B/4R in the rear and 3B/3R up front. Could have used slightly more rebound up front. Car was set to factory ACR specs, which slammed it nearly to the ground, except I added a .5" rake by lifting the rear. Car felt pretty aero neutral like this.

Alignment: No clue. When I lowered the car the rear camber didn't really change. I gained a lot of negative front camber. Whatever the setup it seemed to work pretty well. Need to call Snakebite to get it aligned correctly though.

I will say that with a fairly rookie driver (me), the car was really competitive set up like this and passed every other comparable car on street tires by a wide margin, including a C7 z51 with an experienced driver, and a few Miata's on slicks.

Just reinforces to me that these cars are such a great bang for the buck for a track car. You'd be really competitive with just wheels/tires; a slight brake upgrade - maybe gen 3 calipers on front and fronts to rear with a decent autocross pad (I'm going to PFC z-rated); 6 point harnesses; and good double adjustable coil overs. All things folks do anyways.

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Heading back to the pits after I got black flagged for running off track.

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Dan L.'s viper on the left. Not sure if he's on this site. Sure he'll chime in if so.

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[BoondocSaint]

Thanks for the write up, glad the car is serving you well. If you make any track focused adjustments more to your liking, do an update to your post.

 

[haneifk]

If you're boiling your clutch fluid it might be that the clutch has not been properly bled, or the line is not routed correctly, or even possibly driver error. These cars are made for track use, and shouldn't give you any problems. when I first started out at Waterford hills back in 2016, I would cook my brakes, but improving my driving technique resolved the issue.


Grattan is my favorite track here in Michigan, and perfect for our Vipers in my opinion. A lot of technical aspects and then a nice long straight. Basically like a larger Waterford hills. I'll be doing a track weekend there the first weekend of October, if you'd be interested I can send you the info, can probably find it online too. Would be nice to meet you as well!



I was at mid Ohio for the first time this year and now it's become my favorite track of all time.

At one point the coolant temp light came on briefly but just like most other "problems" these cars have on track, it was driver error. As soon as I corrected my driving technique the light went away and didn't come back on again.

A few things to get the most of your car on the track if you haven't already:

-solid aluminum bushings for steering rack
-check your ball joints, they'll might need replacing. I replaced mine with precision ball joints which might be more money than their worth but I'm happy with the results, the car is much easier to control now
-a proper track alignment
-poly engine/trans/diff mounts
-poly suspension bushings
-replace all tie rod ends/end links
-replace your power steering high-pressure hose. And make sure the ps cap is on tight (People on here have mentioned the importance of this on track)

There's plenty more you can do and I'm sure others will chime in.

Hopefully see you on the track one day!

 

[Dan Cragin]

You can’t let those Conti’s go over 36 hot. Best to start at 26 cold.

Re-route that clutch line away from the exhaust. You most likely have headers

 

[GTS Dean]

Sean,

I've rarely had trouble with the clutch in almost 30 years of track driving. I've run the same Luk pressure plate and disk at modest power levels for 15 years! I suggest a thorough clutch bleed with vacuum assist. I don't use any sort of hi-temp fluid for that. Keep those exhaust heat shields on, or find some and put them on!

I strongly recommend removing the proportioning spring in the rear of the combination valve and experimenting with different F/R compounds. Running street tires, you can't be very aggressive on friction coefficient or front lockups will occur. I like a high initial bite, low torque rear pad with a flat torque curve and a slightly less aggressive front pad with a bit more torque and good modulation. Check out Hawk Brakes' temp/friction graph for their various compounds.

Street tires will always get greasy - you just have to watch tread temps and alignment indicators. I've always preferred a substantial hot pressure split between front and rear tires when on stock widths. Your Mileage May Vary.

I like about -1.4*F/-1.0*R on the street. I find the rears perform better when they're more square and get better life. Pull the front sport shims for the track and let the toe go out. On slicks, you'll want considerably more negative at both ends.

The trans and diff don't have much fluid capacity and they get really hot at the track. Change them both at least once a year.

 

[ISMarco]

I'm happy to see your car being used properly! Here are a few thoughts from a fellow gen 2 GTS driver:

Tires: If the Continentals you have are the Extremecontact Sports, yeah they won't hold up very well to heat. Opinions are mixed on moving to a 200tw or r-compound too soon but they are about the only thing you can hot lap reasonably in a car like this. And with our tire sizes, the selection is limited. I actually run a square set of 315/30/R18 for the track to open up tire options.

Clutch fluid: With well bled good fluid like you have, I would think it shouldn't boil. I do have heat shielding around all of the exposed line and master cylinder in the engine bay on mine, and haven't had issues. I don't have headers either and do run the stock manifold heat insulation. If you do think it's boiling, running Castrol SRF gives you a higher wet boiling point than most (all?) other fluids.

Alignment: This can become important! Front camber will become important if you start seeing the tires rolling over onto the sidewall too far or wearing on the outsides more than the rest of the tire. Rear camber can stay conservative and be OK in my experience. I run ~-3 deg front and ~-1 deg rear and could use a little more negative front camber. Rear toe is very important too, you want more toe in than most cars for the best stability under hard braking. Keeping rear castor even and keeping front to rear rake close to factory has been beneficial too. Some people have issues with the sway bars too if the car is lowered too much. Bump steer can get worse with lower ride heights, but we have a decent amount of adjustment from the factory in the front and rear.

Oiling: Last but not least, pay attention to your oil levels and blow-by. High RPM is also not great for the oiling system in these cars. Definitely use a high quality oil, and consider moving to a heavier weight if you keep driving it ******* the track. I learned the hard way with oil starvation revving high on sweepers, even with the 10qt pan and trap doors.

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[serafins]

You can’t let those Conti’s go over 36 hot. Best to start at 26 cold.

Re-route that clutch line away from the exhaust. You most likely have headers

Dan:
Yes SVS headers. Dan I believe you set the car up for the original owner back in the day! Found the DC performance plaque in the glovebox and glued it back on in the engine bay.

I started them at 25 cold based on trial and error when the road was recently shut down for a couple months behind my house. Nice having a private track in my yard for a bit. Guess I wasn’t far off.

before I re-checked this thread I spent the past couple nights cleaning up the engine bay and re-routing things. The clutch line was way too close to the headers like most guessed. It’s now routed properly and I’d bet it never overheats again.


Dean:
Thanks for the comments. Your advice is noted for sure Especially regarding alignment. I’m going to be playing with tire pressures and brake compounds next time. Been pouring over the friction charts. My intuition based on the feel of the car was to run the Z compound in the front (moderate initial bite, moderate torque, flat torque curve, high heat tolerance) and the DFC5000 in the rear (high bite, low torque, flat torque curve, low heat tolerance). Right now I have the Z compound at both ends, we’ll see how it works.

Without making this any more of a novel than it already is, I just sent the tires to the tire shop to figure out which ones flat spotted.

At the same time I tore down the brakes. rear pads (Stoptech street) had overheated and were disintegrating. Front left had a piece of gravel stuck in the caliper making the front pad stick.

Diagnosis is the rears got weak, requiring more brake effort, which caused the front left to lock up maybe because of the gravel causing the pad to heat up on that side. Tire shop confirmed that only the left front flat spotted. New one is on the way.



In terms of basic maintenance, Every fluid in the car has been changed in the past 6 months. Completely went through the steering and suspension. Bushings, rack spacers, end links, etc were all done between myself and the previous owner. PO put on Howe ball joints. Monster custom aluminum radiator. I just sourced NOS rear Konis and had the fronts rebuilt. And put new springs on.

The entire clutch system (master/slave cyl, clutch/pressure plate, line) was replaced by the previous owner with 0 miles on it when I got the car. I suspect that’s how the line got out of position.

All that to say it should be pretty bulletproof now that I’ve sorted the issues from the shakedown run. Time to tweak it now.

Got some other fun stuff planned this winter for the top end and oiling system…stay tuned.

 

[serafins]

didn’t forget the rest of you guys just ran out of room to type.

Hanefik I’d love to join you on track. Pm me the info on Grattan if you see this. My good friend lives 10 minutes from there and I’ve been wanting to run that track.

ISMarco, car looks great. I actually got the car with R888Rs on it. Hated them. They were 5 years old which I’m sure contributed but they broke away violently with no warning. They were actually some of the worst tires I’ve ever had. I just drove an F2000 Van Dieman with Vitour P1s on it. I think I might pop for a set of those on my track wheels. Kinda pricey but not much more so than the contis these days (and much cheaper than spending $350 at the tire shop after each weekend)

 

[Dan Cragin]

Let me know if you have everything resolved. I have all the specs for the track alignment and ride height for your car if you PM me. Depending on your shocks and spring rates I can give you the compression and rebound settings. The Gen 2 cars can be a good old school track car, lots of torque and tire contact. If you know how to drive one and have some courage you can embarrass some late model sports cars. Big fun.

 

[GTS Dean]

Dan:
Yes SVS headers. Dan I believe you set the car up for the original owner back in the day! Found the DC performance plaque in the glovebox and glued it back on in the engine bay.

Those SVSi headers are NOTORIOUS for burning, melting and boiling everything near them. You absolutely MUST use heat shielding (not just header wrap) and heat socks on the plug wires for track duty! If Dan did the build, then most likely it is taken care of. However, lots of people would rather look at their pipes than protect from radiant heat damage.

 

[Dan Cragin]

Yes, with those headers you need to route a couple of the wires in special way and use heat boots. On the passenger side route the plug wires behind
the heater tube. They make full length socks for the header tubes as well. Once you get it just right, you wont have problems. Many times 2 wires keep
burning over and over again.

 

[serafins]

Thanks gentlemen. Yes I did do some relocation work already and wrapped several lines in heat shield. Happy to report the clutch problems are solved. I will be picking up a set of stock heat shields still to modify.