Brake Hop
11-11-2002, 04:34 PM
#1
Launching!
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Brake Hop This w/e while autocrossing, I got brake hop for the first time with the LG suspension.
The course was in Mineral Wells, for anyone that's been there. It's asphalt that is getting worse every year, and has a noticable slope to it.
Go downhill slolem, then short left sweeper to go parallel with the slope while slightly going left for the next gate, then back right to set up for the hard left. This is where I get brake hop. I'd be up to about 50 or 60mph, hit hard on the brakes in a straight line and get MAJOR hop. This would lead to totally overcooking the turn and wiping out the wall of cones.
*
*--------------------------*------*
*-----------------------------*------*
*---------------------------------------*
------------------*--------------*------*
-----*----------------------------------*
------------------*---------------------*
-----*------------------------------* * *
*=cone
The dashes are there to maintain spacing, this is not scale.
This gives an idea of the course, starting with the slolem on the left. Downhill is down the page. I get brake hop coming in and setting up to make that hard left and braking from about 60 (I wasn't looking at the speedo).
I have the following, all LG parts, in a '02 SS 1LE
SA Lower Control Arms
Torque Arm
DA Panhard Bar
Sub-Frames,V-brace,DS loop
3pt STB
Relocation Brakets (lowest hole)
I was running almost full soft on the rear shocks. 5 sweeps over 2 clicks up front.
Running Kumho's if that helps.
Fittings are greased before the event.
I need help finding where this came from and how to cure it.
Thanks guys.
The course was in Mineral Wells, for anyone that's been there. It's asphalt that is getting worse every year, and has a noticable slope to it.
Go downhill slolem, then short left sweeper to go parallel with the slope while slightly going left for the next gate, then back right to set up for the hard left. This is where I get brake hop. I'd be up to about 50 or 60mph, hit hard on the brakes in a straight line and get MAJOR hop. This would lead to totally overcooking the turn and wiping out the wall of cones.
*
*--------------------------*------*
*-----------------------------*------*
*---------------------------------------*
------------------*--------------*------*
-----*----------------------------------*
------------------*---------------------*
-----*------------------------------* * *
*=cone
The dashes are there to maintain spacing, this is not scale.
This gives an idea of the course, starting with the slolem on the left. Downhill is down the page. I get brake hop coming in and setting up to make that hard left and braking from about 60 (I wasn't looking at the speedo).
I have the following, all LG parts, in a '02 SS 1LE
SA Lower Control Arms
Torque Arm
DA Panhard Bar
Sub-Frames,V-brace,DS loop
3pt STB
Relocation Brakets (lowest hole)
I was running almost full soft on the rear shocks. 5 sweeps over 2 clicks up front.
Running Kumho's if that helps.
Fittings are greased before the event.
I need help finding where this came from and how to cure it.
Thanks guys.
11-11-2002, 07:42 PM
#2
Re: Brake Hop what springs are you running? I have been to mineral wells more times than I can count- since I was 8 years old <img border="0" title="" alt="[Eek!]" src="gr_eek2.gif" />
It is an old course, that is for sure.
A couple of things to check:
Pinion angle. It is supposed to be ~ 1-2*, but just verify it.
Make sure that your LCA is Parallel with the ground. If you have not lowered the car, and you put the LCAs in the lowest hole- that points them upward. Ideally, you want them level.
You could have the shock settings wrong on the rear, not enough dampening for what you need.
Does it do it on the street?
Email me or let me know <img border="0" title="" alt="[Cool]" src="gr_images/icons/cool.gif" />
Louis
It is an old course, that is for sure.
A couple of things to check:
Pinion angle. It is supposed to be ~ 1-2*, but just verify it.
Make sure that your LCA is Parallel with the ground. If you have not lowered the car, and you put the LCAs in the lowest hole- that points them upward. Ideally, you want them level.
You could have the shock settings wrong on the rear, not enough dampening for what you need.
Does it do it on the street?
Email me or let me know <img border="0" title="" alt="[Cool]" src="gr_images/icons/cool.gif" />
Louis
11-11-2002, 09:35 PM
#3
Staging Lane
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Re: Brake Hop I have been racing my '98 since new and have had the same problem (as do many others). I've tried several things and strange as it may sound, here's what works 90% of the time: Push the clutch in when braking! Sounds strange, but it really works. Going into turn one at Gingerman spectators noted several inches of air under the rear tires before I figured this out. Minimal problems after.
11-12-2002, 08:51 PM
#5
Launching!
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Re: Brake Hop </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by steve_c:
[QB]I would recommend running a little more rebound in the rear shocks.
In this case a good set of lca's with proper geometry (parallel) to roll axis should keep the axle down.
QB]</font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">I have the LG LCA's. Poly/rod.
As mentioned, I didn't want to add any more rebound to the rear. Adding rear rebound will make the rear react faster in turns.. and at this site would cause oversteer (which was happening anyway with about 1/4-1/2 turn over 1 click).
I agree pushing in the clutch is a temp fix, I need a better solution.
Would a bump or rut in the surface start the action and heavy braking just continue the situation? Like I said, this is the first time it happened (since modification). It only happened on Sat and not on Sun (although the course was run backwards with a few changes). It could just be the surface, it hasn't happened at the other two sites we autox at.
[QB]I would recommend running a little more rebound in the rear shocks.
In this case a good set of lca's with proper geometry (parallel) to roll axis should keep the axle down.
QB]</font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">I have the LG LCA's. Poly/rod.
As mentioned, I didn't want to add any more rebound to the rear. Adding rear rebound will make the rear react faster in turns.. and at this site would cause oversteer (which was happening anyway with about 1/4-1/2 turn over 1 click).
I agree pushing in the clutch is a temp fix, I need a better solution.
Would a bump or rut in the surface start the action and heavy braking just continue the situation? Like I said, this is the first time it happened (since modification). It only happened on Sat and not on Sun (although the course was run backwards with a few changes). It could just be the surface, it hasn't happened at the other two sites we autox at.
11-12-2002, 10:56 PM
#6
Re: Brake Hop I would have to chalk this one up to the track. I have run there before, and My father stopped running there due to the terrible setup. It was usually dusty, and full of gravel all over the place.
If it doesnt do it anywhere else, then thats all that I can think of.
Is it just that particular corner? Or all of the hard binder corners?
<small>[ November 12, 2002, 10:57 PM: Message edited by: G2 LS1 ]</small>
If it doesnt do it anywhere else, then thats all that I can think of.
Is it just that particular corner? Or all of the hard binder corners?
<small>[ November 12, 2002, 10:57 PM: Message edited by: G2 LS1 ]</small>
11-13-2002, 12:38 AM
#7
Launching!
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Re: Brake Hop Sorry, I forgot to mention I have the G2 springs also.
All parts were installed at the LG shop, so the pinion angle should be right. <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />
No brake hop on the street, I don't brake that hard. And I haven't had any problems on other courses with mostly the same setup (dif shock and tire pressure settings).
This is with the stock brake setup (stock pads even).
The LCA is parallel, but I did notice while changing tires that the dust covers (if that's what they are) on the rod side are slightly coming off the rod end. It's the rubber piece on either side of the rod end.
I was afraid that if I put more into the rear on the shocks it would oversteer badly with the surface out there.
All parts were installed at the LG shop, so the pinion angle should be right. <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />
No brake hop on the street, I don't brake that hard. And I haven't had any problems on other courses with mostly the same setup (dif shock and tire pressure settings).
This is with the stock brake setup (stock pads even).
The LCA is parallel, but I did notice while changing tires that the dust covers (if that's what they are) on the rod side are slightly coming off the rod end. It's the rubber piece on either side of the rod end.
I was afraid that if I put more into the rear on the shocks it would oversteer badly with the surface out there.
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11-13-2002, 12:55 AM
#8
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Re: Brake Hop I would recommend running a little more rebound in the rear shocks. Leave the compression alone, you have plenty with those 180-230# springs.
When you brake hard the car is shifting weight back to front. This unloads the rear and the engine torque tries to rotate the rear axle, forcing it in an upward motion. In this case a good set of lca's with proper geometry (parallel) to roll axis should keep the axle down.
Rebound dampening should also delay the springs from going back to their natural state (extension) and keep the axle down. Any unnatural oscillation is unwanted in this situation.
When you brake hard the car is shifting weight back to front. This unloads the rear and the engine torque tries to rotate the rear axle, forcing it in an upward motion. In this case a good set of lca's with proper geometry (parallel) to roll axis should keep the axle down.
Rebound dampening should also delay the springs from going back to their natural state (extension) and keep the axle down. Any unnatural oscillation is unwanted in this situation.
