after 2 years doing racetrack and performance oriented jobs on the car and lot of chatting on the forum ( thanks to all members that helped me) i took the Vette to the racetrack, and what a surprise!!!

I've never been satisfied by my vette's handling on the street ( unpredictable, scary , somewhat darty etc...) but on the racetrack it's an unbelievable good car , far better than what i expected : predictable, steady , precise handling , straight powerful braking and of course powerful engine. I've been at the same racetrack with my Porsche Boxster , and the Vette is pretty close to the Porsche in terms of handling ( the handling capabilities of Porsches are well known)

unfortunately no pics from the racetrack ( 4 miles road course with 15 turns , 4% to 8.5% banked turns, 1/2 mile straight in front of pits ), but here are some notes about settings and other

Suspension , steering , wheels

the initial intention was to not push too hard and do just a test of the whole car but i ended up with heavily pushing the car in the turns where i felt more comfortable, taking the tires to the limit : no oversteer no understeer just felt the car slightly sliding out flat , parallel . i believe this is how it should be . No power oversteer out of the corners ( 1/2 shafts angled down externally and 3/8" rear toe in and also great, manageable throttle response from the engine - L88 clone-. As i always supposed, more torquey engines like most big inch roller cammed may put you in troubles on a road course, while the L88 is just fine... )

here is the car :
the ride height is not as low as i would like but it proved to be satisfactory on the track (not much body roll) with T tops removed and windows down to lower the center of gravity , and also full gas tank to add weight to the rear






here is the whole set up:

Front :
550lbs coil , 1 1/8 sway bar , QA1 shocks ( 9 clicks or so )
toe : slight toe out
caster : max , 3 deg or so , stock A arms
camber : LF 1,5 deg , FR 1,8 ( check pics)

Rear :
7 leaf spring , smart struts , 9/16 bar , QA1 ( 5-6 clicks or so)
toe : 3/8" in
camber : RL 1,7 deg , RR 2,3

steering : manual , bump steer blocks, Gary Ramadei GTR1999 steering box , 14" sporty steering wheel
(steering effort is not light but ok above all with the small steering wheel. but great feeling : stable and precise. the turn ratio is just fine, no need for a quicker ratio)





please check these pics :
these are the Avon CR6ZZ racing tires after 5 laps (245/60/15 V rated) . I've never been able to take them to this conditions with just street driving ! it seems that i took them to the right operating temperature. And sticking like glue!

I didn't had a tyre pyrometer but from pics it seems to me that i should take all wheels to 1,5 neg camber to have an even footprint



left rear 1,7 deg camber



right rear 2,3 deg camber



left front 1,5 deg camber



right front 1,8 deg camber


Brakes

i've been amazed by brakes : straight powerful braking ,the F R balance seems OK. no fade after 5 laps , but next time at the racetrack i plan to go harder on brakes and see what happens

stock calipers and rotors , Hawk HP plus front , Hawk HPS rear , braided steel lines , ATE Blue fluid , dust shields removed

this how the rims look after the laps with the HP plus pads ( look at the X finger print)




OIL :
after reading of frequent oil priming loss with wet sump while hard cornering -braking ... I added 1qt oil ( GM hi perf oil pan 5 qt) and went a little easier on the throttle in 2 long 180 deg turns ( supposed to be the most critical of the whole track about oil picking up) checking the oil pressure gage while turning: no pressure loss

so probably there's no need for an accusump unless i learn to go really fast in those critical turns and with engine above 4000 rpm

transmission
4,11 rear and M21 close ratio.
i felt very comfortable with the whole gearing. did all the track in 2nd and 3rd , putting the 4th just at the end of the straight ( top speed at the end of the straight is not that hi , 135mph for fast cars ( ferrari,Porsche GT, audi r8 etc) ). I went almost 120mph because i used the last part of the straight to relax the engine a bit and cool the brakes.
next time i'll try to go a little faster

what else?.....

 

Sounds like you had a lot of fun.

 

what were your lap times?

Lance

 

It's encouraging to read your review about your C3's track performance. We all accept the fact they are no match for todays modern sports cars. The fact that you can mention it in the same breath as your Porsche tells me you had enjoyed every bit of your Corvette track day. Are "adjustments" and another trip back out to the track in the very near future?

 

in my opinion well tuned vettes come to life on the track ( or on perfect asphalt roads with grainy asphalt ). Once you don't have to deal with road imperfections then a stiff suspensions Vette is not far from a modern performance car. But sticky tires ( soft compound) are mandatory in my opinion

next trackday available is sept 11 but i don't expect to make big adjustments : just take the camber to 1,5 deg which seems best , add cooling ducts to front brakes.
i would like to add a front spreader bar but i think no time enough so i will delay this thing to wintertime

i had no lap times measurement because this trackday has been a test day : lot of things to check and no intentions to get a real good lap time. i think i can do something better next time and possibly place an imboard camera too



Ahh , aside the tech things there's the cool factor! in the pits all the attentions and interest was for my car despite the presence of 2 Ferrari 458 Italia , Porsche GT etc etc... My car is pretty rare here ( Italy) and you never see at a racetrack. I suppose that when i passed on the straight in front of the pits pulling thru the gears till redline, my car has caught the attention regardless of the presence of big $ cars

 

i had no lap times measurement because this trackday has been a test day : lot of things to check and no intentions to get real good lap times. i think i can do something better next time and possibly place an imboard camera too[/QUOTE]

If you have a roll cage it's easy to buy a camera mount for that. If not, I bought a Fat Gecko two suction cup reticulated mount from Amazon and mounted it on the inside of the passenger window then pulled the arm back and mounted the camera pointing forward. Got good hd footage or running my '76 at VIR in a touring lights mode for a one time deal.

Footage turned out well though the driver, me, was slow! Did improve lap times by a minute each 25 minute on track session starting with no experience at all on a track ever.

Lance

 

why is there such a big difference in L&R rear camber?

 

Sound you doing something right, what do you think is the problem when you are on the street with your set up? I know that a slight toe out is good for the track but is it good for the street? I just started autocrossing my car so I am very knew at this too, i am very glad with performance of the car too. What is the rating on your tires and what size are they?

 

Why would you have your steering toed out in the front to start with? Once you get up to speed, it will toe out even more. If you ask me, that's why it's 'unpredictable, scary , somewhat darty' on the street.

 

the reason has been my lazyness in taking them equal after the last suspensions job... then i decided to leave them like this for the track day so i could experiment with different camber settings ( left and right turns, also right front camber is higher than Left front) and to see which value gave the best thread wear just visually ( no pyrometer handy). these measurement are took with a home gage , not hi tech stuff , so i don't know how precise they are
this is the gage
http://www.summitracing.com/parts/SPS-91000/

 

slight toe out ( or at least 0 ) is necessary for best cornering performance.
my vette is not 'unpredictable, scary , somewhat darty' on straight line on the street , you need to make frequent steering corrections but i don't care about that.
it's 'unpredictable, scary , somewhat darty' when you go onto a little bump while turning. the stiff suspensions of the Vette in performance mode doesn't absorb the bump but jump onto it so the car slides sidewise slightly giving you that bad "feeling"

With manual steering everything is much better. the steering wheel stays tight without amplfiying the road ruts that it's what happens with the vette oem power steering

 

245/60/15, V rated ( straight stiff sidewall )

 

Beautiful car! Glad to see you getting some track time with it. I'm a bit biased about the older cars as my '69 is often the oldest car at most of the track events I go to.

Keep posting the pictures when you get more.

 

I belive you are mixing things up now.

A "tow in" will get your car "darty" a "tow out" will make it stable as a rock in high speeds.

 

Congrats, i belive you have seen the light!.

//Ricky.

 

The few guys I know who short track oval race stock cars where the turns are banked all adjust the angle of the tires from vertical on one side for obvious reasons but the more they adjust the more they fight the car on the straights they tell me. I've only been on one road coarse and only pushed my car to the limits of my experience which was probably 50% of what it would do and with 3.27 miles and 17 turns but essentially flat track though crowned and that you run clockwise with it's three straights of various lengths on the full course, I'd almost want the car set up vertically instead of angled I'd think but I'm very inexperienced.

Good, powerful brakes is number one from what I saw!

Lance

 

Ricky...just looked at your car photos. Outstanding looking. Nice engine...big sucka....

Lance

 

I don`t think so...

 

Great to hear you've gotten that first trackday under your belt! It sounds as tho the Avons are really good.

Tire temp data really can help you set pressures, camber and more as you learn to read them, and IMCO it's time to get yourself at least an IR pyrometer to use routinely. With a little practice my ex became good enough at it (with a probe type) that the tire engineers often compared notes with us, so it's nothing to be intimidated by. I put having a tire pyrometer right up there with having a helmet.

On front toe... With soft CA bushings the front end will indeed move towards or further into toe out with speed. Toe out can help turn-in into the slowest of corners, but while typically beneficial in AX'ing it's not always so on road circuits. Remember, the bumpsteer blocks also increase Ackerman, so you may not need/want quite as much (if any) static toe out in the first place. With poly or solid CA bushings, for RR I'd suggest working from zero front toe as a baseline.

Yes, please do take the time to "square" up your alignment, especially before pushing harder. You ought to go ahead and get the spreader bar installed too.

Best of luck as you gain experience. Definitely keep us posted.

 

you have it wrong.