Discussion of Chassis Setup for 8 Sec. Assault
- Thread starter Alky V6
- Start date
I would think that even with a kit that's designed to minimize bump steer, it cannot be completely eliminated. I'm just trying to figure out what an exceptable range of toe-in gain might be for a car used for 8 second quarter mile runs. Paricularly negative toe-in gain during hard braking.
How much toe-out do you really need before the driver perceives it as a real problem?
Are some drivers more capable of handling more toe-out than other drivers?
If say around 3/16" toe-out could be tolerated by the driver, then setting the toe-in to zero at ride height during heavy acceleration should be a breeze.
Toe out is bad in any form.A double adjustable front shock
can help alot with bump steer with some track tuning.
I hate shim pack arms on the uppers like TRZ.I like pole position arms
easy adjustment no shims greasable bronze upper bushing.I do like
the limiter adj on the TRZ arm simple and effective.If the chassis is set set up right a very small wheelie and no bump steer!My bigger concern
with the g body is aerodynamics over 135 mph that added to a 10 psi slick makes it down right dangerous thats why most people are moving to
raidials.
can help alot with bump steer with some track tuning.
I hate shim pack arms on the uppers like TRZ.I like pole position arms
easy adjustment no shims greasable bronze upper bushing.I do like
the limiter adj on the TRZ arm simple and effective.If the chassis is set set up right a very small wheelie and no bump steer!My bigger concern
with the g body is aerodynamics over 135 mph that added to a 10 psi slick makes it down right dangerous thats why most people are moving to
raidials.
I'm running stiff wall slicks with tubes, so I'm probably more stable than some may think. I will experiment with more pressure though. That was already suggested to me and is planned.
Toe out under braking is not a problem missed that post.
I align passenger cars with alot of overall toe out all
the time they dont feel unstable but thats at hyway speeds.
With the extra positive caster it will calm down the
wander from the toe out.So the increase in caster in the dive helps out
as well.I think the bumper in your application will work well.
I align passenger cars with alot of overall toe out all
the time they dont feel unstable but thats at hyway speeds.
With the extra positive caster it will calm down the
wander from the toe out.So the increase in caster in the dive helps out
as well.I think the bumper in your application will work well.
On the subject of suspension travel limiting. The bolts, chains and straps have got to shock the suspension when they come into play. Is that a good thing?
What I've done was bolted in an extension of the pad on the frame where the stock bumper of the upper A-arm hits. Presently, it is built up high enough that there is very little clearance between it and the stock rubber bumper. As the suspension rises, the bumper makes contact and begins to compress. The point where the bumper stops compressing is at 2" of suspension rise.
The bumper is a variable rate spring by design and helps avoid the suspension shock at full rise.
What I've done was bolted in an extension of the pad on the frame where the stock bumper of the upper A-arm hits. Presently, it is built up high enough that there is very little clearance between it and the stock rubber bumper. As the suspension rises, the bumper makes contact and begins to compress. The point where the bumper stops compressing is at 2" of suspension rise.
The bumper is a variable rate spring by design and helps avoid the suspension shock at full rise.
I ran the stiff slicks as well and was amazed how small spoiler changes on the vehicle changed the overall stability.I feel i could benefit from more
rear down force.i would love to here from the fast guys on this one.
Very good. That's exactly what I wanted to hear. Time to reset my toe-in!
I will still modify my dive bumper, though. Under hard braking at the track, it feels like I'm going to flip over the front end, the thing dives so much. Not a comfortable feeling.
Are you referring to the front spoiler?
I know todd at TRZ says to start at 3/4 of an inch gap on the bolt style arms.
I dont know if shocking the suspension is an issue, but it will be hard to adjust your system for differant track conditions during qualifing
3/4" would be about 1.5" rise travel.
Yeah, that is a limitation for me with the way I'm doing it. The extension is held in with one bolt, and it can easily be changed out over the fender. No crawling under the car. I suppose if I found that I needed a different travel I could make another extension with a different height and just change it out quickly in the pits. I've found that a 1/2" change in the height of the extension equals close to 1.0" in travel change.
I suppose if I wanted even less rise than I have now, I could increase the extention height and begin trimming down the rubber bumper. The trimmed bumper would yield a smaller compression range from start to total compressed height.
johnplogii
Senior citizen
- Joined
- Aug 13, 2005
I wasn't trying to say that I know anything about suspensions on the toe-put thing. I am just going by a personal experience on my wifes car this winter. She slid off the road & hit a snow bank, moving the control arm to where the car was toed out. The car was a bear to drive with severe oversteer, meaning you barely touch the wheel & the car would go right HARD, then barely go left & the car would go left HARD. Maybe this was an extreme case with alot of toe-out? I don't know how much it was, but I do know the car was scary to drive above 40mph.
Blocking off the grill will be the next step. That will be easy.
Then, after that, it will be time to play with the spoilers.
I will be extending the front full length spoiler to the limit allowed by NHRA. I believe that's 3" clearance to the ground.
The stock rear spoiler might be able to be played with by adjusting its angle. I don't know if anyone has played with that, but it seems to me that might be worth playing around with.
Then, after that, it will be time to play with the spoilers.
I will be extending the front full length spoiler to the limit allowed by NHRA. I believe that's 3" clearance to the ground.
The stock rear spoiler might be able to be played with by adjusting its angle. I don't know if anyone has played with that, but it seems to me that might be worth playing around with.
I found a taller front spoiler. TR Custom Parts - Air Dam - Full Width
I'm probably going to end up making my own one-off spoiler. The spoiler from TR Custom Parts is 1" taller than the stock one, but I'm going for something taller.
I'm debating whether or not I want to design in a splitter for the new front air dam.
I'm probably going to end up making my own one-off spoiler. The spoiler from TR Custom Parts is 1" taller than the stock one, but I'm going for something taller.
I'm debating whether or not I want to design in a splitter for the new front air dam.
I thought I'd add these links.
http://www.turbobuick.com/forums/threads/g-body-drag-car-alignment-settings.290592
http://www.turbobuick.com/forums/threads/8-second-oem-4-link-drag-race-chassis-setup.289613
I just re-read these threads and there's some good information in them.
http://www.turbobuick.com/forums/threads/g-body-drag-car-alignment-settings.290592
http://www.turbobuick.com/forums/threads/8-second-oem-4-link-drag-race-chassis-setup.289613
I just re-read these threads and there's some good information in them.
Thanks Donnie. It's been a while since I read those threads. You're right. It's very good info and I hope that I helped you some. Just wait, there's more to come. I'll be starting a thread myself to give you some more ideas, in the next few months, they just won't be legal for a "stock" car class.:biggrin:
I look forward to your thread, Charlie. Let me know when you post it.
I measured the front spoiler, and to bring it to a 3" ground clearance would mean a drastic increase in the height of the spoiler. Very wierd looking.
I settled for a 4 inch increase to the stock height of the spoiler. That will give me 5 inches of ground clearance. That should give me 3 inches of ground clearance during hard braking. The bottom of the spoiler will meet the low point of the exhaust pipe that exits in front of the right front tire. Maybe, still wierd looking, but not as much.
It will need to be easily removeable so the car can be loaded into the trailer and tied down without complications from the spoiler. I'm going to hold off on a splitter for now. Maybe a simple, very short one to aid rigidity to the bottom edge of the spoiler. Make it strong enough to be a mounting point if in the future I decide to try a larger splitter.
I'm thinking of getting creative with the shape of the front spoiler. Not just simply following the OEM contour. Maybe following the shape of the Nascar Sprint Series Cup cars, but without the splitter.
I measured the front spoiler, and to bring it to a 3" ground clearance would mean a drastic increase in the height of the spoiler. Very wierd looking.
I settled for a 4 inch increase to the stock height of the spoiler. That will give me 5 inches of ground clearance. That should give me 3 inches of ground clearance during hard braking. The bottom of the spoiler will meet the low point of the exhaust pipe that exits in front of the right front tire. Maybe, still wierd looking, but not as much.
It will need to be easily removeable so the car can be loaded into the trailer and tied down without complications from the spoiler. I'm going to hold off on a splitter for now. Maybe a simple, very short one to aid rigidity to the bottom edge of the spoiler. Make it strong enough to be a mounting point if in the future I decide to try a larger splitter.
I'm thinking of getting creative with the shape of the front spoiler. Not just simply following the OEM contour. Maybe following the shape of the Nascar Sprint Series Cup cars, but without the splitter.
