Holding car on starting line w/stock brakes
08-07-2017, 08:33 AM
#1
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Holding car on starting line w/stock brakes I have a Circle-D 4200 stall converter, leaving at 2300-2500 RPM. The car will sometimes creep when staging. New rotors (not slotted/drilled), new calipers, hoses, fluid, OEM-type semi-metallic pads. Hardly ever run the car on the street.
I know the right answer is to install Drag Brakes, but I was wondering if anyone has experience with aftermarket pads (Hawk, G-Loc, Carbotech etc.) to hold the car better. Or maybe AC Delco organic pads are enough(?). Don't care about squeak or dust. Plenty of shutdown area so no problem with finish line braking. Need low temperature grip and good release for reaction time. Thanks.
I know the right answer is to install Drag Brakes, but I was wondering if anyone has experience with aftermarket pads (Hawk, G-Loc, Carbotech etc.) to hold the car better. Or maybe AC Delco organic pads are enough(?). Don't care about squeak or dust. Plenty of shutdown area so no problem with finish line braking. Need low temperature grip and good release for reaction time. Thanks.
08-07-2017, 09:46 AM
#2
When I swapped my rear end out my brakes didn't hold as well, so I just rebleed them thoroughly and haven't had an issue yet. Something to try if you haven't.
What rear gear do you have? A numerically higher gear will tighten the converter up and want to push through versus a numerically lower gear.
I don't have experience with any of the brake pads you asked about, sorry.
What rear gear do you have? A numerically higher gear will tighten the converter up and want to push through versus a numerically lower gear.
I don't have experience with any of the brake pads you asked about, sorry.
08-07-2017, 10:32 AM
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Holding car on the line I have bled the brakes many times. I'm sure this is not an issue with air in the lines. The brakes otherwise work great.
The rear has a 3.73. I would think I should be able to hold the car at 2500 with a loose (4200 stall) converter. But it's really hard to hold it there. I need to have that starting line RPM (at a minimum) in order to hit the tree.
Trying to get some support from the brake pad manufacturers, but so far, no one has given me a solution.
The rear has a 3.73. I would think I should be able to hold the car at 2500 with a loose (4200 stall) converter. But it's really hard to hold it there. I need to have that starting line RPM (at a minimum) in order to hit the tree.
Trying to get some support from the brake pad manufacturers, but so far, no one has given me a solution.
08-07-2017, 12:00 PM
#4
I have bled the brakes many times. I'm sure this is not an issue with air in the lines. The brakes otherwise work great.
The rear has a 3.73. I would think I should be able to hold the car at 2500 with a loose (4200 stall) converter. But it's really hard to hold it there. I need to have that starting line RPM (at a minimum) in order to hit the tree.
Trying to get some support from the brake pad manufacturers, but so far, no one has given me a solution.
The rear has a 3.73. I would think I should be able to hold the car at 2500 with a loose (4200 stall) converter. But it's really hard to hold it there. I need to have that starting line RPM (at a minimum) in order to hit the tree.
Trying to get some support from the brake pad manufacturers, but so far, no one has given me a solution.
08-07-2017, 01:25 PM
#5
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Not sure if this helps, but I have stock front brakes and smaller explorer 8.8 calipers in the rear. I can hold 3k with an SS4000, pro drag radials, and hawk hps pads.
08-07-2017, 10:08 PM
#6
Have you thought about using a line lock? I have a FTI 4,000 stall with Wilwood street/strip brakes all the way around and mine won't hold past 2800 rpm.
My best times come from flashing the converter just off idle. It's more consistent too because it's hard to watch your tach and cut a light at the same time. Every car reacts differently and so you have to find the sweet spot. Mine is when the third amber is fully lit I gas it. I can usually be .040 or lower. But it takes trial and error. But it is fun to beat cars that are over half a second quicker than you because they can't leave!
My best times come from flashing the converter just off idle. It's more consistent too because it's hard to watch your tach and cut a light at the same time. Every car reacts differently and so you have to find the sweet spot. Mine is when the third amber is fully lit I gas it. I can usually be .040 or lower. But it takes trial and error. But it is fun to beat cars that are over half a second quicker than you because they can't leave!
08-08-2017, 07:04 AM
#7
He'd have to use 2 line locks, one for the front and one for the rear, but I don't think it would help him out much.
A lot of times I find that my brakes get a bit funny when I hold the RPMs up a bit. There isn't enough vacuum and the brakes rely on vacuum. I've thought about trying a vacuum reservoir inline between the brake booster and the intake manifold to try and combat this.
Maybe try pumping the brake pedal up a bit before you start to bump in to build up some pressure?
Are you bracket racing, or heads up racing? If bracket racing are you allowed to deep stage? You could just leave off of idle deep staging, but it may still react too quickly depending on how fast your car is.
A lot of times I find that my brakes get a bit funny when I hold the RPMs up a bit. There isn't enough vacuum and the brakes rely on vacuum. I've thought about trying a vacuum reservoir inline between the brake booster and the intake manifold to try and combat this.
Maybe try pumping the brake pedal up a bit before you start to bump in to build up some pressure?
Are you bracket racing, or heads up racing? If bracket racing are you allowed to deep stage? You could just leave off of idle deep staging, but it may still react too quickly depending on how fast your car is.
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08-08-2017, 08:36 AM
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Holding the car I am bracket racing on a full (sportsman) tree. We need to "courtesy stage" (both driver light the pre-stage bulb before anyone stages), so there really isn't enough time to get into a deep stage deal. Have to hold the RPM manually, since 2-steps are not allowed.
Have tried pumping the brakes etc. I think it's a good as the current hardware will allow. Different pads were the only thing I could think of.
The car may run faster off idle, but I can't hit the tree bottom-bulbing at a low RPM. Reaction times are faster and more repeatable at 2300 RPM. Everything would be better if I could hold the RPM higher.
Brian's Hawk HPS pads comment is something to think about. I didn't know if the HPS compound offered anything better for static grip, over a semi-metallic pad.
Have tried pumping the brakes etc. I think it's a good as the current hardware will allow. Different pads were the only thing I could think of.
The car may run faster off idle, but I can't hit the tree bottom-bulbing at a low RPM. Reaction times are faster and more repeatable at 2300 RPM. Everything would be better if I could hold the RPM higher.
Brian's Hawk HPS pads comment is something to think about. I didn't know if the HPS compound offered anything better for static grip, over a semi-metallic pad.
Last edited by MikeSp; 08-08-2017 at 08:52 AM.
08-08-2017, 09:00 AM
#9
I bracket race too and do the courtesy stage with a sportsman tree. I tried many things but for me it's easier and more consistent to light the stage bulb and a slight build off idle. That way I'm not concentrating on the tach and flashing the converter too high and rolling through the light. My sole concentration is on the amber light and cutting a reaction time.
I've found the more consistent your staging routine is the more consistent your reaction time and et are. If your staging deep one time because you rolled too far flashing the converter one run and then stage shallow the next, then your reaction time and et are inconsistent.
Not saying you're wrong, it's just what works for me.
If you're set on flashing the converter I'd hold your line lock button after you stage so you know your front brakes are locked. I can't say how consistent that will be because I've never tried that.
I've found the more consistent your staging routine is the more consistent your reaction time and et are. If your staging deep one time because you rolled too far flashing the converter one run and then stage shallow the next, then your reaction time and et are inconsistent.
Not saying you're wrong, it's just what works for me.
If you're set on flashing the converter I'd hold your line lock button after you stage so you know your front brakes are locked. I can't say how consistent that will be because I've never tried that.
08-08-2017, 10:40 AM
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Holding the car No electronics allowed in our class. I'm already at 45 psi on the 25" front tires. Have adjustable front shocks and those are pretty tight too. I really think its all about the brakes from here on out. I'll probably try the Hawk pads. Their HP Plus compound seems to have the highest coefficient of friction at low temperatures.
08-08-2017, 01:21 PM
#12
Finally, some bracket racers to talk to!
I've tried all sorts of stuff to cut a better light.
What model is your Circle D converter? Perhaps you can talk to them about maybe loosening it up a bit?
I've tried all sorts of stuff to cut a better light.
What model is your Circle D converter? Perhaps you can talk to them about maybe loosening it up a bit?
08-08-2017, 03:30 PM
#14
You're going to have to adjust your staging method. Fully stage at idle, then hit your target RPM, can't take but a second to rev it up.
Going in with the RPM at 3000 will leave you no braking vacuum - AND hot transmission fluid. Ideally, you shouldn't be on the converter more than 2-3 seconds total.
Al
Going in with the RPM at 3000 will leave you no braking vacuum - AND hot transmission fluid. Ideally, you shouldn't be on the converter more than 2-3 seconds total.
Al
08-08-2017, 04:21 PM
#16
You're going to have to adjust your staging method. Fully stage at idle, then hit your target RPM, can't take but a second to rev it up.
Going in with the RPM at 3000 will leave you no braking vacuum - AND hot transmission fluid. Ideally, you shouldn't be on the converter more than 2-3 seconds total.
Al
Going in with the RPM at 3000 will leave you no braking vacuum - AND hot transmission fluid. Ideally, you shouldn't be on the converter more than 2-3 seconds total.
Al
Foot braking a converter may generate some heat, yes, but nothing like what a transbrake will do.
08-08-2017, 06:52 PM
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Holding car I have an AutoMeter DPSS gauge that flashes at the starting line RPM, so you can focus on the tree and see the LED's turn on in your peripheral vision while staging.
But I like the cable-set RPM idea. I've heard cars that went straight to the starting line RPM, but never looked at how they did that mechanically. So with the cable deal, I assume you just have to push the cable in at the finish line to get back to normal idle.
In my case, all of this depends on the ability to hold the car. I had a good conversation with Tech support at Hawk Brakes today, and they suggested the following part numbers for brake pads (mine is a '99 FBody):
Front: HB249W.575
Rear: HB250N.653
Fronts are the DTC-30 compound, rears are HP-PLUS. Hawk claims that the DTC-30 is best for low temperature grip, but also works better for higher temperatures (finish line braking). Rears are not available in DTC-30, Hawk claims that HP-PLUS is second-best. I will try their recommended pads this weekend and see if we can hold the car any higher. Will report back.
Thanks for all the comments and ideas.
BTW, my converter is a Circle-D, 4L60 LS Pro Series Stage I 245mm 2E. Circle-D did a great job matching the converter to this engine. Picked the car up from 60' on and still seems very streetable. I gave them the list of mods and the RWHP and they said it would stall at 4200. That's exactly where it stalls. I'm sure it could be loosened, but we're really close to where we want to be - except for the brakes. If the Hawk pads work, I'll be very happy.
But I like the cable-set RPM idea. I've heard cars that went straight to the starting line RPM, but never looked at how they did that mechanically. So with the cable deal, I assume you just have to push the cable in at the finish line to get back to normal idle.
In my case, all of this depends on the ability to hold the car. I had a good conversation with Tech support at Hawk Brakes today, and they suggested the following part numbers for brake pads (mine is a '99 FBody):
Front: HB249W.575
Rear: HB250N.653
Fronts are the DTC-30 compound, rears are HP-PLUS. Hawk claims that the DTC-30 is best for low temperature grip, but also works better for higher temperatures (finish line braking). Rears are not available in DTC-30, Hawk claims that HP-PLUS is second-best. I will try their recommended pads this weekend and see if we can hold the car any higher. Will report back.
Thanks for all the comments and ideas.
BTW, my converter is a Circle-D, 4L60 LS Pro Series Stage I 245mm 2E. Circle-D did a great job matching the converter to this engine. Picked the car up from 60' on and still seems very streetable. I gave them the list of mods and the RWHP and they said it would stall at 4200. That's exactly where it stalls. I'm sure it could be loosened, but we're really close to where we want to be - except for the brakes. If the Hawk pads work, I'll be very happy.
Last edited by MikeSp; 08-08-2017 at 07:14 PM.
08-08-2017, 07:22 PM
#19
Cable operated throttle control. Pull lever inside car and it pulls throttle blade open against a stop. When I hit the throttle pedal it overrides the stop and goes to wot. When you release lever returns to idle.Deadly consistent launch rpm and very adjustable.Works pretty good.
08-08-2017, 09:20 PM
#20
Cable operated throttle control. Pull lever inside car and it pulls throttle blade open against a stop. When I hit the throttle pedal it overrides the stop and goes to wot. When you release lever returns to idle.Deadly consistent launch rpm and very adjustable.Works pretty good.