Tom400CFI

Went up to Miller Motorsports Park yesterday, for the Lapping Days event. Awesome event, venue with tons of on-track time. Recommend it to anyone.

'92 Corvette, all stock except for:
C5 front brakes,
RBF 600 Brake fluid
Hawk HP+ (Edited) pads
Koni's
Bridgestone RE751 tires on C5 Z06 wheels.

Track day went good. Car ran flawlessly –after the first session. The first session, my brakes started smoking w/in 2 laps. Like really bad. I could smell it something fierce. My driving was terrible. I couldn’t get the car where I wanted it on the track at all. I was scared and I kept turning in way too early, requiring f’ed up steering corrections. It was a mess. Typical of my driving for “First time back”. Like when I go karting and the first session I spend bashing into the walls.

Anyway, first session was unrewarding, and confidence-sapping with the stinky brakes. I basically felt like I was beating on the car, for no benefit at all (fun). I took a cool-down lap and then to add insult to injury, when I came off track, my brake pedal went to the floor –boiled fluid, and there was smoke pouring from both front wheels! WTF? How could that be??? I upgraded rotors, calipers, pads, and fluid, since my last session, and while it didn’t boil in <5 laps like before (when stock), it still boiled. I was upset, and confused. I basically have the same hardware that the C6 had, but with better fluid, in a car that’s the same weight. How could I be having all these brake issues? I didn’t get it. Still don’t.



I almost packed it in, I was so upset, and I felt that any further track time would only ruin something, and possibly make the car undriveable for the 7 hour trip back to the middle-of-no-f’n-where. Well, I let the car cool and headed out for my second session. My driving was 10x better and that “felt” great, and I started to have fun. I regained my confidence and started pushing it, aware that the brakes might boil, but I’d push until they did. Well, they never faltered. No smell, no fade, came into the pits at the end and no boil or smoke. Nothing.


Each successive session, I drove harder, figuring that at some point I’d run into boiled fluid and I never did. I really started pounding the car toward the end of the day as I did two full sessions “going at it” with a Porsche 944Turbo that had tires. We were pretty evenly matched, although I could pull him on any straight; I’d gain about 5 cars on the back straight/kink. But I was pounding the thing at the end of the day, and no issues at all. Weird.



Other than that, the thing ran f'n awesome. I love that car. I ran the RPM’s well into the redline (R@5500, I was shifting 3-4 at ~5800) over and over and over, all day. Oil temps never went above 270, coolant never went above 210, trans is awesome, and I started adding rev-matched downshifts in turn 10 so I could come out onto the front straight in 2nd w/some high RPM LT1 punch, then bang 3rd, 4th down that straight to gain more on that Porsche where I could. It was awesome fun. Tires worked good and didn’t wear noticeably…it’s a fantastic car. Needs three things: more low end tq (or 100 more hp), lowered, and rubber bushings replaced w/heim joints. There is a lot of “wiggle” in the rear when heavily loaded in corners. I want it to feel like my old Trans Am did, which as I recall, was very firm/flat and hard. Great day at the track. Only thing that would have made it better would have been having one of my pal’s there with me.

EDIT: Video, HERE
The quality went to crap when going to You Tube. Sorry about that. I wish it remained better...

383vett

Sounds like a fun outing.

Sidney004

Be careful, you may already be addicted. It sounds like your pads were getting bedded in on that 1st session. The HPS pads are mediocre at best for track usage. I run full race brake pads all the time and just tolerate them on the street. You really should get a set of race pads and slip them on before your next event.

Aardwolf

Awesome! Any video?

I had some HPS on for my first event and they overheated in two laps, just like you're describing. I had to limit top speed and use the brakes less. It was a good learning experience! It's possible you were dragging them or using the brakes lightly for a longer distance. Rather than quick threshold braking.

For turning in, pick a marker for the turn in spot so you don't get anxious and turn in to early. Extra camber in the front really helps the car turn in also.

The wiggle sounds like more chassis control is needed. My car came with Z52 and it felt wobbly on track. Get some Z51 springs from Ralph (Indianavette) and large sway bars. Change out some bushings and get better shocks. That will work well for awhile!

c4cruiser

Try Z06 pads in front and Hawk HP+ in the rear. The HPS pads are fine for "spirited" street driving and autocross but for track use, they don't really have the performance needed for track usage.

Also look at CarboTech pads.

Aardwolf

Z06 pads were as bad as HPS for me. They are both good street pads.

Kubs

Sounds like you might have been dragging the brakes a bit on the first outing like Andrew mentioned. HPS pads are not at all up to the task of driving hard.

Other than that, sounds like you had some fun!

96GS#007

No way would I run those pads on a C4 on the track. C4s are heavy and need (IMO they require) brake cooling.

The nice thing is that with your setup, it forces you to take it pretty easy on the engine and the car in general. You'll be able to do lots of trouble-free track days. Just don't climb into a well-driven but otherwise stock C5 or C6 Z06. If you do, prepare to empty the wallet

Toy90

Using those pads without front cooling ducts is a receipe for disaster. I went off track with HP plus pads once after 1 lap at Second Creek Raceway in CO before they closed it down a few years ago. I ran the exact same pads with cooling ducts in the front that I made from dryer ducts from Home Depot and could run all day with no fade while using R-compound tires during 90 degree temps. I would still recommend some actual race pads from Carbotech or Hawk even with cooling ducts just to make sure your brakes don't limit your fun. It's a sick feeling when you are going 90 mph heading for a hard turn and you stand on the brakes and don't really slow down.

93Rubie

Don't feel bad Tom at a recent auto-x drivers school I had something similar happen. I (we, instructor was driving) boiled fresh 3 month old DOT3 on stock pads. That was in the morning, I ran the car all afternoon with NO issues. I did bleed/flush the system with Motul RBF 600, had some really nasty brown fluid coming out of the LF. Needless to say I'm going to upgrade to auto-x pads as well, just not NOW. If I boil RBF 600 auto-xing I'm doing something wrong. I figure the cheap pads that came on the car transfered more heat to the fluid than a more high performance pad would. Instructor said before the fluid boiled brakes where biting well. Fairly high speed course with a Chicago box. Those things are fun once you figure them out. I got it right in the afternoon but failed to change my braking point for the next corner and kept screwing it up, WAY TOO much speed. Soooo.....addicting....

@96GS007, so what you are saying is stock to stock the C4 is a cheaper more reliable track car. Given a few braking related modifications. ???

Isn't talking about racing/auto-x/road course a lot more fun than Opti-Spark, and Coolant threads!!!

Tom400CFI

I have video, but am trying to figure out how to DL it from my new GoPro. It DL's in MP4 which I can't seem to do anything with.

I miss-spoke above: I have HP+ pads, NOT HPS.

The shocks (Koni) weren't set to their firmest setting. I won't make that mistake again. But I agree that more spring, sways and getting rid of "rubber" would help a lot.


No...it wasn't that. I wasn't "two footing it". Driving w/one foot.

Again, sorry for the misinformation on the pads. Also, I had Z51 C6 prior to this and although it definitely produced better NUMBERS...it was no more fun to drive on the track, and less fun on the street.

Sidney004

The HP+ pads are nothing to write home about; the pad compound is still probably the cause of your braking issues. The next step up on the Hawk lineup is the 9012 Blue which I've always liked. Its a really old compound design but an effective pad.

Aardwolf

I got a chart from them at an event awhile back:



I prefer to run Carbotechs but I've used almost every compound on there.

Adam@Amp'dAutosport.com

I will be happy to help you with a set of Carbotech pads, if you decide to go that way. I would start with XP10 front and XP8 rear.

JrRifleCoach

Tom, sounds like your on the mark for a new hobby. And a good lesson of bedding in brakes for future reference.

Have fun!

Kubs

Dragging the brakes could also mean, if you are unsure of braking points at first, you tend to start braking sooner and stay on them longer rather than get to the braking point, stand on them hard and then get off them quickly. The extra bit of braking will heat them up quickly. Sometimes you may not even know you are doing it. Since it was your first session out in a while this could have been the case.

Aardwolf

Not bedding the pads will not cause that.

Crepitus

IIRC the HP+ is pretty hard on rotors Adam can get you squared away. Glad the day worked out for you!

96GS#007

Nah, over the long haul, my opinion is that a stock C5 is cheaper to run than a stock C4. Almost all the consumables on a C5 are cheaper. However...it's certainly cheaper to buy a C4 initially and it takes a lot of track days before the cheaper C5 consumables pay off. People also need to consider that once they start time-trialing or running in the Advanced and Instructor groups that it's not much fun being a rolling pylon for faster cars all session long. As such, it's pretty challenging to leave a C4 stock.

93Rubie

Yeah, but C5 seats stink on ice.

I mostly auto-x in STOCK class so for now my car is staying stock. For me to go to B Street Prepared I could literally spend 5K in a heat beat just to get the car competitive with suspension/brake/tire modifications.

Its a lot fun to just play in stock street tire class and beat up on much newer machinery. That and in the Western PA area other than the Solo Chair of my local club NO one is running a C4 Corvette in auto-x that I have seen. That includes Allegheny Highlands SCCA and Steel Cites SCCA. Maybe a couple floating around Central PA SCCA and North Hills Sports Car club, but you get the picture.....

I need some better tires and some track pads plus some cooling ducts (base 12" brakes) and then I'll get this car up on the track at PittRace or Nelson Ledges isn't too far away either. A couple club members are going the end of the month, maybe next year, sigh....