ChumpVette

Looks great on track!

for power steering, where was the failure? High pressure line or rack? If it is the line, DRM sells a braided line as an upgrade. Other leaks or issues come back after diagnostics.

proper pad compound and ducting of air to the rotor goes a long way. Thermal capacity of the C4 J55 isn’t the greatest. Cheap improvement will be to a C6 caliper with an adapter. You can use the Delco rotor or just hit Napa and grab them and use and toss.

Tom400CFI

$10 bux that it was the high pressure line cracking, right under the nut on the pump. I've lost two, on track from that. Hose vibrates at high RPM...fractures it's only supporting point, which is the under the nut. Hose needs a bracket.


X2 on the C5 or C6 upgrade....I was boiling brake fluid out here at Miller Motorsports Park/UMC on stock calipers/rotors (not J55) so I did that upgrade(I used C5 parts). I vote NAPA (or other) parts store rotor. First, I've found Delco rotors to be, ah, dog ****.....second, the NAPA Ultra premium has directional cooling blades, correct for each side. OEM rotor is one "directional" casting....used on both sides. Dog ****.

VikingTrad3r

Wogden, palmer is on my bucket list. There is another C4 owner who runs there. I will see if i can connect you. He is in a red 89 fe7 Z51.

ive seen his videos (did you take any vid? :-)) and palmer is on my bucketlist with all the rock outcrop. i love it!!

Anyway, maybe its the elevation causing your brake fade? How long are your sessions? Im not really sure whats up with that i am running both J55’s (regular and the grandsport version) and i get a good 30min session now out of my brakes prior to fade. Pad compound is Dynamic Friction “Active performance” or their “Trackday Pad”. Ive used the powerstop Trackday pad too. Its also good. And im in a ZR1 half the time so heavier.

I’ve actually found the better i get the less brakes i use. So strangely, im getting faster and using the brakes less. Whereas i used to HAMMER the brakes to slow me down prior to turn in now i just take the speed into the corner and trail brake to the apex and then on power to trackout. my pads are lasting longer. i use the cheapest rotor i can find. always solid. brake fluid i use is motul 660.

do not have brake ducts but those are my next upgrade.

i use redline power steering fluid. both my track cars are slowly losing their powersteering efficiency. planning on a turnone rebuild over winter for both pump and rack on both.

Wogden

Thanks for the responses. A friend of mine took some video but I don't think he's uploaded it yet. I did not have a GoPro in the car. I don't quite know where the leak in the power steering was but high pressure line sounds like likely as I went from smelling smoke to seeing smoke to losing power steering within three turns so the fluid went out fast.
I'm coming to the realization that the brake pads and rotors that were in the car were just junk even though they were new they were cheap garbage. The brake fluid was Dot 4 so I'll upgrade to the 660 and stainless braided lines. Corvette Central has a C5 upgrade kit for the calipers and rotors, is that what y'all are talking about? I've used Napa stuff for years in other applications and I know they make quality stuff so once I upgrade to the C5 calipers I can just run Napa's best stuff is what you're saying?
I'm not building a serious track machine but something I'll take the track 1 to 3 times a year. Largely just for fun.
this is my first time running any sort of organized track event and it was a blast COMSCC is a great group and I had a great instructor. Palmer is an amazing track if I had one bad thing to say about it is there's very few places to watch the action. In fact volunteering to be a flagger would probably get you the best view of the track.
a lot of BMWs and Miatas on the track yesterday. A few c5s and c6s and one C8.
I was the probably the third oldest car out there aside from a fox body Mustang and a Porsche 944 and maybe a early Miata or two.
we were running in the clockwise orientation which is fairly new at Palmer so even the most experienced guys were struggling in places like how to connect Turn 5 and 4. At the end of the day nobody had quite figured it out. It's downhill and off camber to turn five and there's a lot of rubber on the track from people going in the opposite direction and it's in full sun so it was greasy to boot.

VikingTrad3r

my thoughts are that rotors are rotors are rotors for the C4 J55 stuff. I dont believe that one companies metalurgy is differthan another. Not based on my experience.

As far as pads, yeah now thats a different story. As mentioned i use either active performance or track day pads. rock auto. cheap. the active performance pads wear out and save my rotors. i like it.

Tom400CFI

We should talk/text about this one. I'd like to do this too, for a couple reasons:
1. It looks awesome/fun/interesting....especially compared to UMC.
2. I'm from MA, so have a bunch of friends who live there, who'd come out w/me....which tracking w/friends is way WAY more fun.
3. We could also go to New England Dragway, and run some basement numbers w/our cars. 88' above sea level!

I'd do that drive, for that/those experiences.

yakmastermax

By the end of my first season tracking my 1989 ZF6 with factory steering setup, the high pressure line of my power steering system was leaking. It appeared to be leaking from the rubber to metal seal area right at the fitting that goes into the pump, like Tom said.

I replaced it with an OE style hose, but wish I had gone DRM. The job was actually oddly tough because of the tight spaces to work the wrench to tighten and loosen the fitting, and getting the pipe fittings started in the steering rack and pump was tough because of the tight space, the nature of angled tapered pipe fittings, and the fear factor of cross threading the fittings going into the rack and pump.

Tom400CFI

Went to UMC today. The story of today is both uninteresting....and scintillating, at the same time.
Here are the uninteresting facts; Went to UMC today, did one, 1hr session, car ran great, no issues, burned about 3/4 of a tank of gas in 1 hr. Had fun.

Now, here is the scintillating story; I ******* LOVE this car. It is SUCH....A GREAT....CAR! Going into the day, I was having some aprehension about it. IDK why, but I was having unfounded "feelings" that the car wasn't ready, it might break, tracking it is hard on it, it's going to abuse it....blah, blah blah. I even considered backing out....but went ahead and dragged myself out there. Met my friend Andy, who is a driver on Champ racing team "Bandits" (they campaign a black "Bandit" Trans Am), he had his personal car -a '17 370z with minor mods; brakes, intake, exhaust, wheels/tires, "track alignment". I have 12 year old Koni's.




We hit the track, and due to my apprehension about everything, I started off slowly. I was basically just 'driving my car around the track'. Andy created a large gap ahead of me, he was 4-5 turns ahead of me after a couple laps and by that point, I figured that catching him was an impossibility, but finally decided that I should "get to work", anyway. I cranked up the pace and after 1/2 a lap was enjoying the car, and started in with the "pushing". I was rewarded with a faster pace and the car "pushed right back" (in the right ways). The tires got warm and started STICKING....the steering became immediate. The brakes didn't fade...they got better! Engine ran awesome, pulled hard past the red line, over and over and over....ran about 215, oil 260 on this hottish, low 90's afternoon. **** yeah....let's GO! Confidence went no where but UP and I start really driving the car; into the brake zones, into the corners, hitting WOT just barely past the apexes....and the thing was ******* unflappable! I could pile it into a turn way to fast....and it didn't even matter! It would bite and corner like it was NBD.

I caught my friend Andy in a lap and a half? Two laps? Passed him w/a point by on the front straight and proceeded walk away from him like we were in radically different classes. His car has 330 hp. Really? I'd get 1/3 to 1/2 a lap ahead, then slow and wait for him, give 'er hell again and walk away. During one of these cycles, I'd waited for him to catch up, then started charging again...dove into Turn 7 (Agony&Ecstasy), check my mirror to see how Andy was doing and......DOH! Off track, he went! Dust flying, he was fine but I didn't wait this time...I was "feelin' it" and kept charging. Car was doing GOOD.

I came up on a C8....it had two; an instructor, driving, and an owner, riding. They were going slow, gave me a point by and I passed...as soon as I got by, though, the guy was ON me. I thought, "O.K....let's go". I went hard...as hard as I dared to go, safely, and he was on me. Every turn that I'd hit hard, execute good and come out of w/a ton of speed, I'd think, "I probably gained a length there", and I check my mirror...he was right there. On me. We did two laps that way, and it was FUN. Although he was "there" the whole time, I felt that there were moments where I was holding my own. I enjoyed the **** out of us lapping together for as long as I felt that I could, then I gave him the point by. He passed and I decided to give it everything I had, to see what I could do. Did I think I could keep up? No, but what could this car and I do? A lot. I did way, WAY better than I'd hoped. As he passed, I got on it, piled into the first turn right on him....stayed on him all the way through turn 1 (East One). Turns 2/3 are WOT, 4(Gotcha) is maint throttle "floater" w/some pucker factor. W/190 more hp than me, the C8 pulled me pretty good through this section, but....he blew his entrance into turn 5! I came in under him and gained everything back, held onto that through turn 7, then he pulled me good up the hiil to the Attitudes where I braked way too late and made that back up. I slammed the car through the Attitudes, tight,but hairy as **** at that speed and came out onto the straight headed for the Tooele Turn, right on his ***. I was PUMPED...and things were rockin' and rollin'! I was having a riot!....it was SO FUN! He pulled me down that straight, I gained a little in the Tooele Turn, held on somewhat down the next straight and made up a little through the CHC, Wind-up and Release. I really tried hard for a fantastic exit to Release to make up for my major lack of HP, and I think I did OK....but it didn't matter....he gained 5 car lengths on me down the front straight and there was nothing I could do about it. I mostly held that gap for the next full lap, eeking everything out of that car, that I could eek....After the next front straight, I threw in the towel....Session was almost over, and I'd done the BEST that I could do...and the car had done it's best too!

That segment of driving was on the ragged ******* EDGE, for me. Several turns, I'd pile in and think; "There x amount of mass, going Y speed (way too fast) and Z distance to the "end" of the asphalt (outside of the corner)....and ain't no WAY this car's staying on the track....but that car would dig and scramble and bite, and would somehow, gobble up another corner.

At the end of the session, the C8 was already parked in the pits when I rolled in. I saw him and headed his way....however "dorky" and lame it may have seemed, I intended on telling him what a HELL of a FUN piece of driving that had been; he and I. As I rolled up next to him, he saw me coming and said out his window, "Nice driving, man....NICE job!". It was cool. I replied to him, "It was the most fun I've had all summer!" He came back one more time, "NICE job". I know that I can't hang w/that car, but I think I did pretty good for a little while. I was stoked. Pumped. Jacked to the ****! But mostly, the whole episode had been absolute, unbridled FUN!!

I remember reading every car mag article about C4's when they were out, that I could read. They were winning at Escort/Challenge car racing, they always won every car mag handling shoot out (in spite of other draw backs). They dominated that time frame. I remember reading that they were harder to drive than other cars, but with enough skill, they'd win. I remember thinking (naively), something like, "Well, I"m a bad *** and I could smoke anything, with one of those (C4's)!" "Who CARES, if it's' harder to drive!!" Today, I feel that I was actually able to recognize what they were saying in those articles about "harder to drive"....and I could play with and flirt with that characteristic. It wasn't like the car was going to "bite me", spin, or anything like that....it's more like, as you approach or reach the car's limit, it's kind of like "All hell breaks loose". It gets crazy, chaotic, scary, "loose"?....but the thing never stops "biting" or hanging on. You can keep on pushing even more than the "limit"....and there's even more limit beyond crazy, chaotic...etc. It can do it, and it does. It's not a comfortable feeling b/c it feels like you may well leave the track....but you can keep pushing and it keeps going.

What a car. I bought this ******* thing, 14 years ago as a repairable....a cheap, fix 'n flip. It's got 210,000 miles and I hammered the hell out of it today, for an hour straight....and it hammered right back! LOVE IT.

'78CorvetteS.A.

Excellent post^^^^^^^^!!!! I felt like I was right there with you in the car!!!....Like I didn't want to get into tracking my car someday in the first place, after reading that, I'm having all kinds of feelings to get my a$$ out there and do it! Tom, you have a knack for story telling!!! Thanks for helping fuel the dream👍

VikingTrad3r

@Tom400CFI

I knew u were not going to make it a season without going to the track. That is a great post no doubt.

If you could capture that feeling and sell it as a drug u would be a gazillionaire. The C4 is starting to get the cred it deserves on track!

bls72bmw

Guys, tried to search the thread but didn't find it....and it's a long thread to scroll through...

Whats the conventional wisdom for street tire pressures on track with a standard C4 (not fully prepped, aka a street car)

I will be going to Brainerd this weekend, 3 day DE Event. Running Continentals 340TW as the back up tires, and Goodyear SuperCar F3 Street Tires (not slocks) TW 220? as the primary tires. Not sure what you guys suggest I set them at to start/cold. The Contis are 17" 285s and the GoodYears are 275s on 18" Rims.

Ambients will be 60F in the AM, 72F for the high.
THANKS!

MatthewMiller

Keep in mind that whatever cold pressures you start with, you'll gain probably 5psi in a 20-minute track session if you're really pushing the car. It's those warm pressures we're really aiming for. I have it easier in my Camaro because the TPMS system gives me accurate, individual pressure readings on track. You'll have to check each time you park in the paddock right after coming off track.

The Goodyears don't like a lot of pressure. On my Camaro (significantly heavier, but also wider tires), I shoot for hot pressures of around 33 front and 31 rear. My car is a little weight-baised toward the front, and the rear tires/wheels are wider than the fronts, so you might end up shooting for even pressures front and rear on a square-fitment C4. I'd probably look for 32psi hot, which means starting with cold pressure down around 26-27psi and being careful on your out lap to wait for the heat/pressure to build. These Supercar 3s are great track tires! What rim widths are those 18" wheels?

I haven't tracked those Contis, but I have tracked my Camaro on Michelin Pilot Sport 4S tires, which are very similar to the Conti ExtremeContact Sport. Ergo, this is an educated guess. The Contis will have more sidewall. I'm assuming they are on a narrower rim width too (like maybe stock 17x9.5)? Also, while they will tolerate moderate track use, they weren't designed for it like the SC3s and they probably won't revel in the heat you can generate on a really smoking lap (the Goodyears love that kind of use). Given all that, I'd guess that 35psi hot is a good target. Start with 29-30psi cold and then check right after you come off track. Adjust as necessary.

bls72bmw

Super helpful- the Contis are the street driving/back up set- they are on 17x9.5" rims (285 width is a bit wide for these but is listed as OK). Plan to start first couple sessions on these, taking it easy, and learning the car.
THEN, the Supercar F3s are 275 width on 18x10.5" rims, should be a good set up (As suggested by you and others here on the forum).

MatthewMiller

Yep, 285/40 is a bit of a pinch on a 17x9.5, and it's tall with lots of sidewall compared to the Goodyear. As I mull it over, you might want to target more like 36-37psi for them. I love the 18x10.5 fitment for those SC3s. The Goodyears are going to be a big difference compared to the Contis, and I'm not sure there's a good reason not to just start out on them. They just have higher limits and more steering response, but they are very honest and straightforward tires: no tricks or surprises. They are also pretty forgiving, in that once you get them slipping they have a wide envelope within which they maintain near peak grip. And they are OE street tires on the 1LE and ZL1 Camaro, so they aren't going to wear away in one track day. I think I got five full track days on my last set, including three full days at my local roval, where the inside tires get eaten alive on their inside edges on the looong, banked NASCAR 3/4 turns. And that's on a 37000lb beast with less aggressive rim width for the tire widths. They aren't very durable for autocross use, but I think that's because they want to be run at hotter temps than you can generate in a 60-second run. You can just pound them for long track sessions and they love it: they generate plenty of grip without abrading away quickly. I think you'll get lots of track days on those.

VikingTrad3r

id leave pits with 30psi square and adjust as needed. pay attention to squirm due to width in rim.

👍👍👍👍👍

glad u posted! will u take some pics and maybe even video!


are u street alignment? are you z51 and do u have fx3? if u r street alignment, you will want to take nice wide radiused turns. you can carry more speed doing this so it wont affect your times much, but you will want to use literally every inch of track width to create the most reduced radius turn as possible in order to avoid seriously wearing the outside of your tires.

if u like the track, you could go for a max track alighnment. 👍

bls72bmw

Team- wow what great weather here at BIR- thanks for the tips and the help ; it is amazing to me how well this 94 C4 is doing running around with all the Porsches! Bested my personal time in my old 2001 Boxster- the Corvette platform definitely has a learning curve, you can't just dive and brake deep deep into corner and toss it over, definitely takes some planning. I am amazed how well this 29year old car can hold its own on track~ My car has zero mods, a base model car with a 6speed, just a well maintained car, stock brakes with good Hawk Pads, SS lines, etc. Bilsteins all around, I could see upgrading this car and having fun with it. My Hawk Pads after 2 days are getting low...I should have brought extra TRACK capable pads....so I have a set of O'Reilly 50$ pads to put on in case it all goes South....I am wondering if they are even worth putting on? I will probably make it through the first 2 25 minute sessions tomorrow AM, but I am unsure about the last 2.
First day on the Contis' and they actually did pretty well for me! They break away a bit sooner and give some warning, second day on the Goodyear SuperCars...holy cow those are amazing tires. I "feel" like I have slicks on! I am getting a LOT of wear on the front left outside shoulder.....I have an 'aggressive' street alignment on- it is clear a person needs to determine wether or not to go all out and prep the car for the track....or street it. I do plan to move to a C5 this winter....so I think the C4 will find a new home...but let me say how happy I am in this car for my skill level and abilities. MUCHO THANKS TO THE FORUM GUYS who helped with contributions.....

VikingTrad3r

well thats good to hear u had fun. You can ofcourse toss your $50 pads on. Pads dont go from 100% to 0% they tell you they are not happy if it happens. you are able to detect and feel the difference btwn the tires so the same will be with the pads.

i have a c5 6spd and a c4 6spd and i ALWAYS take my c4 to the track. 🤔. If im cruising on a roadtrip, i’ll take the c5. If you remember next year, come back and tell us what you think. Is the C5 a FE1 (base spring) car ir a FE7 (z51)? A C4 FE7 spring car is an absolute complete total blast. Bliss on track with a maxed out front camber/caster.

Go figure.

bls72bmw

So....why do you prefer a C4 on the track to the C5? I kind of like the "underdog" idea of the C4...

VikingTrad3r

VikingTrad3r

c5 is numb. smooth. soaks up the road. like a modern car. A C4 is a modern car with modern suspension, but analog.

As soon as you evolve from the C4, you might as well go to a C7. Obviously i understand the dollar difference between a c5 and a 7. But the tech is more or less the same with iterative improvements in engine power and braking.

C4 is unique in that its suspension design can keep up with modern cars, but the driver has no aids, no nannies. IOW, C5 too easy