Holding Car at Starting Line Brake Questions!
 

My 99 C5 has all new brakes and rotors. Problem is after a few mths of drag racing I lose braking to hold at starting line. I have tried ever pad that Napa makes no luck. So was wondering can I upgrade to C6 brakes on frt or rear or both. To get this thing to not push thru brakes. I have 17' wheel on car and they have to stay because I have a combo that works. Can not get car to leaving like it should as I can get it to stall up to 2800 when they are new but that dont last long. Seams like I have brake fade. Just wondering if I can change caliper's or something to get this baby to hold? I also have a line lock on the car. Trying not to break the bank here! Any Idea's Guy's.

What brand line lock do you have? To me it sounds like you're losing brake pressure not a brake pad/caliper problem. You are getting the tires wet and only doing a burnout for a few seconds? After the tires get hot yes she'll push sometimes. You are pumping the brake 3 times and holding firm when you set the line lock? What does your brake pedal feel like? Hard/squishey?

cartex line lock but it did that before line lock. I am getting maybe 2200 rpms at tree when all new I get 2800. Which cost me .07 in 60 ft times. Pedal feels fine but when u get to line it feel like MC is ready to bottom out then pushes thru brakes and car rolls forward.

Oh good grief thats what i get for not reading things completely. I'm thinking burnout prior to launch. At the line is obviously different. I being a 6spd guy may not understand this as much but I didnt think if you had a 2800 stall converter the car wouldnt put much power to the rear wheels when foot braking it till close to that rpm when it comes in. 2200rpm and the car starts pushing seems like the converter is ready to go whether you are or not. Have you tried flashing it up as high as it'll go before the launch? For example I know some will sit there and have the rpms up slightly and floor it right as the lights come down the converter flashes higher and the car launches higher. This could vary depending on how tight/loose the converter is setup. Try sitting ont he street and doing it see whats it doing.

when I do it on street brakes let go! Have Yank ss3800 converter. It will not sit no matter what. Wonder if I buy another set of frt brakes and put on rear that will help?

I was only able to preload my SS3800 to 2200 before it would push through the brakes. I think that was normal for that stall. I don't know how you never got your brakes to hold at 2800, maybe your trans flulid was cold and the tc wasn't grabing. ??

I have a 3200 YANK and I can't load it up at the tree to 2800 it too wants to pull through!

So I keep mine down around 2200-2500 the when the light smashes the last yellow it's to the floor and up it goes - getting a low 1.6 60' - Will be better next time out (New tune at 701 RWHP and 582 RWTQ)

You also might want to bleed the brakes, it may not solve the problem but you will at least eliminate any old juice in there and will be sure there is "NO" voids too!

Go to a synthetic or the DOT4 fluid, see if that helps! NAPA brakes may not be the best for dragging so you might try HAWK pads or GM's Z06 Pad (if you haven't already)

Are you by any chance using ceramic pads? If so don't! :D

Thanks,Matt

I have a Yank 3600 and it won't hold that high either.

Pitt

vig 3600 in mine starts creeping at 2600.holds 2400. try pumping up brakes 3times to see if you can get a little more pressure to hold at higher stall

Well the converter is kinda loose :D I have raced most of my life & I have tried all the tricks. wont stay still but sometimes it does when stuff is new but is not like I think it should be.

I need more clamping power. What about putting a set of frt brakes on the rear of C5?? Bought a brake bias spring today as suggested by VBP. I am also putting in new brake fluid. Thinking braided lines also.

Just wondering... could it be your front tires are not holding back the constant torque?
Could water still be on your front wheels at the line?
Just wondering...

tires are not scootin and no water on tires. we have to back into water!

same setup for me and i cant get past 2400-2500

Usually the fronts will just push with the wheels locked before the brakes let loose so I would focus on rear brakes more. Try an "H" compound road race pad for better grip. You are near the point of where those convertors start to lock though.

by H do u mean Hawk. Can u put just rear calipers like on frt on rear or will bias get u in trouble??

"H" like a Wilwood "H" compound pad, we have them in stock for $159.

You could put a larger caliper on the rear, but that seems like a lot of work for the reward to me.

Have you tried switching to synthetic fluid and/or braided lines. The fluid could be failing and you are losing pressure or the normal rubber lines are expanding causing the pedal issues.

When I change bias spring I am changing fluid also. Is synthetic fluid better for pedal firmness than reg brake fluid?? I dont have braided hose's but may get them as I know they will firm up pedal some.

my 4000 stall is at risk of pushing through at 2100 rpm. Luckily, it is eough fo low 1.4s and high 1.3 :)

Interested in knowing how that bias spring works out....let us know

I change to ss lines and flushed system of old brake fluid and will give that a try. Then if that dont work will tackle bias spring. Off to strip friday to test.