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I might as well throw this in here. This is my former car from a couple Saturdays ago at Autobahn Country Club track in Joliet, IL. I was there in my Camaro. FWIW, the nose is now painted but the current owner ran out of time to get that done before this track day. I'm pretty sure he set the fastest lap time of the day before the heavens opened up and rained on the second half the day.
Matt, you cant just stop there. How is the car setup in general? Square? Tires, Springs? Dampers? Brakes?
If you insist...
The suspension has offset lower control arm bushings up front for increased camber, with plain poly bushings in the upper arms (Global West Del A Lum would be the shizznet for the uppers and Van Steel now has Delrin offset lower bushings). In back it has Banski rod-end camber rods and trailing arms. I think he has camber set at -3 front and -2 rear, but in that pic it looks like it could probably use more rear camber (I'm going from memory on those numbers...the point is you want lots of camber for radial tires). Springs are VBP (no longer business, sadly) Xtreme leafs adjustable for corner heights front and rear and with rates of 1125lb/in front and 550lb/in rear. I think the sway bars are still what I had on it when I sold it: OE 30mm front bar and OE 23mm rear bar. Shocks are some custom-valved Bilsteins up front and off-the-shelf Koni sports rear (if I'd kept the car I would have gotten something better).
It has Wilwood 6-piston front brakes and 12.88" floating rotors, which really help for track use. Rear brakes are stock. I forgot which pads he installed, but he said they weren't up to the heat from the 20-minute track sessions. They were chosen more for autocross use. The owner before me used some legit track pads and they were great, but they didn't work well at all on the street or in an autocross (needed way too much heat).
EDIT: I forgot to add that the new owner installed the Detroit front hub adapters that allow the use of SKF X-tracker bearings. It's about $1000, but almost guarantees you'll never need to change front hubs at an event whereas the stock ones (no matter the brand) almost guarantee that you will sooner or later. The fronts are easy to change, though. There is a similar adapter kit for the rears from Van Steel, but it's 2500-fricking-dollars. Not installed. The stock replacement rear bearings suck also. Buy spares and bring the tools with you to change one out at the track. They aren't as easy as changing the fronts, but you can still do one in 30 minutes if you have the right tools and you've done it before (a cordless impact with a long extension and T55 bit will help a lot). It's better than losing a whole track day when one of these POSs fails, and IMO it's better than shelling out $2500 for the upgrade kit.
Wheels in the pic are 18x11 et50 Forgestar CF5 with 315/30/18 Falken RT660s, both front and rear. They did great and were probably the best tire on this day, but the temps were not above 40F while it was dry. On a hot day, the Falkens may overheat a bit and get greasy. The Continental Force tires might be better for long sessions on hot days - I'm not sure. For 18x10" wheels or even 19x11 wheels, Goodyear Eagle Supercar 3 are great hot-day track tires too. The C4 is a light car, so it will be kinder to tires in terms of both wear and heat than my fat-*** Camaro...if you can dial in enough camber to make them wear evenly.
The engine has been discussed ad nauseum in other threads, but it's a 396 LT4 with heavily ported stock heads (they flow like AFR 195 Race/Competition heads), ported LT4 intake, and a small Comp Cams custom grind. It pulls hard from 2500-6000rpm. The current driver in the pic above used to have a C5 with a hot LS1 that made something like 490rwhp, and he entered it in many Optima events and even got the invite to the big event at Vegas last year. I drove that car and it felt broken compared to mine: power wouldn't come on until 3500-4000rpm. He got out of Clifford (the C4 we're discussing) and said it was way faster and pulls hard no matter what RPM/gear he's in. He loves it. I think it feels even faster than it really is because the midrange is so stout. That kind of powerband goes a long way toward making car easier to autocross or drive on a road course because you don't have to spend much mental energy trying to keep it in a narrow rev range. It has a Fidanza aluminum flywheel (13lb), a stock ZF6, and stock D44 with 3.45 gears. It's been shown to slightly pull a stock C6 Z06 from a roll. On track that day, he left me in his dust on the straights, and Camaro is good for a 115mph quarter-mile trap speed. It was so bad that my son was riding shotgun in my Camaro laughing at me. A Dewitt's radiator and a nice big oil cooler keep the temps in the green no matter how hot and long the sessions are, and the engine was designed for a higher redline with a more radical cam so it will never die with the cam that's in it now. Your only limit for track time is the capacity of your fuel tank and bladder.
Here's an in-car of the owner before me driving at Motorsport Ranch in Houston, probably from around 2011 or 2012. Most of the hardware is the same, including the entire engine (like I said, it won't die):
Matt, did you have to upgrade the factory power steering fluid cooler or was factory one adequate? Thanks! Kevin
The factory one seemed to be adequate for track duty. It's probably more stressed during an autocross run just due to the more frequent and more extreme steering inputs. Luckily those runs are short with good cooling-off time in between...usually. My car did have a Turn One power steering pump and valving, but I don't think that necessarily helped keep the fluid cool.
I've been wanting to ask this for a while; mine whines excessively on both track days and auto-x. IDK why. It's as if the fluid is getting aerated and causing the sound. Steering works fine, but you can hear feel the hum/buzzing and it's not the greatest. Shut it off for a bit and it's fine until the next beat session.
I've been wanting to ask this for a while; mine whines excessively on both track days and auto-x. IDK why. It's as if the fluid is getting aerated and causing the sound. Steering works fine, but you can hear feel the hum/buzzing and it's not the greatest. Shut it off for a bit and it's fine until the next beat session.
I do know this has been an issue for other C4 drivers. I never had it in mine. Mine had fairly heavy steering, like the valving was causing to provide less assist (on purpose). So maybe that was somehow keeping it happier with less pressure/heat? I confess to not knowing a lot about steering gear. The only other thing I did differently than many was to use the Joe Gibbs synthetic power steering fluid, #01307. I think it's now marketed as "Driven" brand #01306. I used it because the previous owner used it with good success, not because I researched it. I'm sure the usual players in the synthetic fluids game also have PSFs, and maybe they work just as well. Or maybe the fluid has nothing at all to do with it.
No reason for me to start a new thread for such a simple silly question...
Next race in the series is May 7th. Last race my oil temps got up to 280 degrees F several times. In preparation for the May 7th race I changed the oil in my 1989 yesterday. I have never see worse looking oil in my life (granted I have a tiny fraction of the automotive experience that some of you guys have). It was VERY BLACK and very thick and "sludgy". It did not appear to have any coolant or anything else in it, just super black and viscous.
I assume things things are okay, and this is just the expected result of racing a small block chevy up to 280 degrees engine oil temperature?
Would it help some of yall make a call if I poured some of the oil in a jar or something and posted a picture?
I assume things things are okay, and this is just the expected result of racing a small block chevy up to 280 degrees engine oil temperature?
Not normal. My GUESS is that it's the result of poor maintenance (lack of oil changes) by the previous owner, and you're cleaning that **** out w/the new oil and high oil temps. Keep changing the oil. Have you had a peak into the oil fill hole to see if there is sludge build up in the valve cover area?
Originally Posted by yakmastermax
Would it help some of yall make a call if I poured some of the oil in a jar or something and posted a picture?
No that won't help much. Taking an oil sample and having it analyzed would be much more informative.
Not normal. My GUESS is that it's the result of poor maintenance (lack of oil changes) by the previous owner, and you're cleaning that **** out w/the new oil and high oil temps. Keep changing the oil. Have you had a peak into the oil fill hole to see if there is sludge build up in the valve cover area?
No that won't help much. Taking an oil sample and having it analyzed would be much more informative.
I will more carefully inspect the rocker arm area under the valve cover here shortly. Maybe sludge was a strong word to use... but compared to the brand new oil I put it, it was noticeably more viscous and some of the darkest oil I have ever seen.
FWIW I had the oil done at a lube shop shortly after purchasing the car (maybe 1500 miles after buying it), then I put 2800 miles on it plus that one track day after that oil change, then changed the oil yesterday.
Copy. My oil gets to about the same temp; about 280 or so, on the track. I drain it and it looks/feels about the same as when I put it in. But my engine is CLEAN, inside. Like new.
your hot temps would have cleaned out a load of sludge like tom said.
it took about 5 oil changes for me and it cleared up.
eventually i pulled the valve covers and intake manifold to give my “refurb” treatment and there was still grit and sludge in the nooks and crannies of the head.
what i did.....was run cheap dyno oil and get the oil hot and simply do lots of oil changes. Once it was all cleaned up i used a full synthetic 10w40 and never looked back.
Actually Tom has quite a thread going on how hes seen modern oil will clean out sludge slowly over time. my experience has been the same especially with hot temps on track!
I cant remember.....do you have the kc4 oil cooler/heat exchanger?
I raced at the second race of the series yesterday, and had a great time again. The new exhaust got lots of compliments, and I set a new personal best of 1:41.6 seconds (with my girlfriend in the car, so down 12.5 horsepower lol and at the end if the day with the track getting hot) down from a 1:43.7 session best from last month. I am a little bit disappointed as I was hoping to get into the 1:39.X area. The track record is 1:30.03
Driving skill and lines aside lol, since last session I did smog and egr delete, long tube headers and straight pipes, throttle body coolant bypass, got an alignment done, and flushed the coolant and replaced it with 100% distilled water plus coolant additive. The car ran a good bit cooler, and I think I can hold off on messing with the radiator until the season is over. Last time I hit 280 F oil temps and around 240 F Coolant temps. This time coolant temps really didn't go above 230 F at all, and oil didn't go above 265 F. Still hot, and not great, but workable in my opinion, unless yall think otherwise.
Turn 2 and 3 of the course are part of a double apex that I am really struggling with, but I am working on it.
All in all I had a ton of fun again. I want more seat time and to improve my time, but I also want the car a bit faster.
I think my rear wheel bearings were on the way out before the race (was having rear vibrations for a while) and doing the grab and flex test with the wheel I was getting a decent amount of play, and now after the race the vibrations are definitely worse.... so wheel bearings on are on the menu front and rear before the next race. I will probably pull the half shafts and do U Joints at the same time.
The vette really did great and I am happy with it. I don't think I am quite at the limits of my brakes yet (spending too much time with neutral input to the car), but at the same time I don't want to find the limits of my brakes on or off the track. A part of me wants to just save up and go with a Wilwood kit, and another part of me thinks going with aggressive street/ light track rotors, pads, and stainless lines is the way to go. I am confident that the later option combined with better fluid and a good bleed will more than suffice for this season...but I prefer to do this sort of thing not in stages. Eventually I want the Wilwood brake kit. I think the one I am considering comes out to $1800 to $3500 depending on if I do front and rear at the same time or not...
Just upgrading the current pads and rotors, lines and fluid maybe would be $800 tops?
We'll see.
Anyway, I had an awesome time yesterday and so did my girlfriend. I feel even more motivated to improve my driving and the car.
Also, slightly related to the "Most power from an L98 TPI" thread, between my first track day and this most recent one, it has become very obvious to me from an experiential standpoint why so many on this forum and elsewhere in motorsports/autosports have their preference for the LT1 engine over the L98, and for wide flat torque curves and high revving motors in general. This was something that I never really understood from first person experience until recently. I always "knew" that it was good for racing, but I didn't know. Now I know. I almost makes me want to buy another C4, preferably a 92-95 LT1 6 speed or a 96 LT4 as a more "race" car and to keep the TPI 1989 as more of a street car. The bottom line is that wide, non peaky power bands are good for racing. Maybe at a drag a peaky TPI setup can still holds its own thanks to area under the curve, and on the street it obviously has its advantages, but for road/track/course racing... I have a hard time articulating it but boy do I want that 8k tachometer in the LT4 car now lol. My original plan was to throw money at the 1989 TPI, do a 383 or 396 stroker with the nicest heads I could get, maybe even procharge it, to "make up" for the fact that I was going to keep it "TPI". I'm thinking now I'll still do the top end (TPIS Big mouth base, AS&M runners, plenum, extrude hone, roller rockers) but then I'll stop there (motor has 60k miles on it, not reason to rush to stroke/bore it) and save up for an LT1/LT4 car. Between the labor/time/cost and the cost of AFR 195s, a nice 383/396 bottom end etc, cam etc... I'm well on my way to just getting an LT1/LT4 car, which would then allow me to halve the wear and tear I put on either car. Just thinking out loud with fellow C4 enthusiasts!
VikingTrader, I do believe I have the oil cooler. I can see the send and return line on the adapter that is in between the block and the oil filter. I think I'll just upgrade the radiator this winter.
Last edited by yakmastermax; 05-08-2022 at 10:31 AM.
In another thread, Yak's alignment sheet says they put in -3 degrees in each side of the rear (something like that - going from memory). Then there is basically no camber up front, and they took caster out so it only has around 4 deg. There is a question as to whether his rear wheel bearings and/or halfshaft U-joints are shot, which may be contributing...because I was actually surprised that a stock C4 could get -3 deg rear camber with the stupid stock eccentric adjuster. So he is looking at doing the bearings (still another thread), and I strongly suggested he take the car back for a proper alignment. He needs all the negative camber a stock C4 can get up front, and then maybe -1.5 (if possible once bearings and U-joints are good) in back. Finally, those of us in the thread on the wheel/swaybar interference now know, the steering wheel on Yak's car isn't oriented on the shaft properly, so his steering geometry is all kinds of screwed up. So he's got work to do. It's all part of the game, though.
The pics are great! I have paid for a package like that more than once at big events. I'm still mulling over buying a set from my last track day since it has my son riding shotgun in all the pics (I can't believe they allow passengers either!).
04-14-2022, 10:40 AM
