LT1-LT4 Modifications 1993-97 Gen II Small Block V8

uprgraded suspension question

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Old 12-20-2010, 07:52 AM
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Originally Posted by curacaoz28
where can I read more about this geometry problem??
do a search in the drag race section on here there is a big thread explaining this.......also check out the google button

Originally Posted by MattSapp95_T/A
Out of curiosity what hole you do have your lower control arms in on your relocation brackets?

Thanks
Matt
Im on the bottom hole.....

Originally Posted by DVS LT1
Word - I'd like to figure this out during the winter for next year.

My old setup I was running Eibach Pro springs which gave a 1.3" drop front to back. My LCA's instead of being "somewhat" horizontal as they were in stock trim were now angle upward toward the rear wheels.

I imagine the ideal is to have your LCA's horizontal when you car is at full launch - as in, wheels have hooked, weight has been transferred, and your rear end basically hitting the floor (shocks & springs are as compressed as they can get). Correct me if I'm wrong here. Or do you want those LCA's to face at a downward angle towards the rear wheels?
You actually want the LCA's at like a 2-3 degree down angle........if the are up its actually trying to push the rear end up into the body instead of down to the road......

Originally Posted by speed_demon24
Why would you want your car to squat on the launch?
You wouldn't!!!!!......its a common misconception that a car should "squat" on the launch.....people think that this means the car is "pushing" the rear into the ground when in fact its actually not.......there are two different forces in this case depending on how the rear of the car is setup....

Squat: Which is when we see the rear end moving up into the body; this is actually reducing the amount of force pushing the rear end into the ground

Anti-squat: Which is when we see the fender well gap actually grow on the rear end when the car takes off, which means the rear end is being forced down into the ground and away from the car.

Now, it seems as though we would want as much antisquat as possible to launch the car right? Wrong.....too much anti-squat and the car will shock load the tires and then unload quickly which will give you an issue I ran into personally this year untill i fixed my instant center. The car will bite initally and then begin to spin because the suspension is unloading to quickly. There is an even balance on every vehicle where the suspension loads and then remains stable through the whole pass.......this is just scratching the surface of launching a car but hopefully it will clear up some things on squat/anti-squat

Here's a good picture of anti-squat on my car...........

Heres a picture of the car sitting normal at the starting line before staging..........notice the fender well gap between the rear tires and the body......



Now heres a picture of the car on launch..........notice how the fender well gap has grown.....this is anti-squat.....



Originally Posted by DVS LT1
Not necessarily saying you'd want that - that's what my rear use to do when I'd hit the track (with BFG's mind you. Tires would hook and rear end would "squat" as you say. With the harder Firestone's I still have it didn't do that, but then again they don't hook either, they just spun).
The reason they didn't hook is because of that squat see above response ^

You have to think of it as what direction is the rear end moving in the car? Not what direction is the car moving? The tires are attached to the rear end not the body ........all that movement is in the wrong direction and is actually being taken up through the suspension........a bandaid solution is to stiffen the back of the car up but again its like putting a bandaid on a bullet wound....it will make it a little better but its still not the solution.....
Old 12-20-2010, 08:02 AM
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quik95lt1 thanks for that reply lots of good useful info there.
Old 12-20-2010, 08:34 AM
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Look at the sidewall flex in that second pic! Awesome.

This is indeed good info. So let me ask this: how come rear end drag shocks and springs tend to be much looser/softer than normal or race track setups? I always assumed you wanted to rear loose…

I’ve yet to hit the strip with my new setup (next summer) but I’ve got the stock rear springs back in and QA1 12-way single adjustable shocks. On the street this past year I played with them a bit – having them set to mid point and ultimately full loose. With the Firestone tires I have on the car now it really didn’t matter as my tires spin like crazy. What setting do you think will be the sweet spot for drag racing?

I was holding off getting relocation brackets b/c who knows how long my 10 bolt will be around. But I may just weld on a set next year and get those LCA’s facing downward. But 2-3 degrees? Would that even look noticeable? Heck my LCA’s were once facing 10-15 degrees upwards with my old setup; figured 10-15 degrees downward would be the aim. Meh… looks like its time to get into that drag racing section.
Old 12-20-2010, 08:42 AM
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Originally Posted by DVS LT1
Look at the sidewall flex in that second pic! Awesome.

This is indeed good info. So let me ask this: how come rear end drag shocks and springs tend to be much looser/softer than normal or race track setups? I always assumed you wanted to rear loose…

I’ve yet to hit the strip with my new setup (next summer) but I’ve got the stock rear springs back in and QA1 12-way single adjustable shocks. On the street this past year I played with them a bit – having them set to mid point and ultimately full loose. With the Firestone tires I have on the car now it really didn’t matter as my tires spin like crazy. What setting do you think will be the sweet spot for drag racing?

I was holding off getting relocation brackets b/c who knows how long my 10 bolt will be around. But I may just weld on a set next year and get those LCA’s facing downward. But 2-3 degrees? Would that even look noticeable? Heck my LCA’s were once facing 10-15 degrees upwards with my old setup; figured 10-15 degrees downward would be the aim. Meh… looks like its time to get into that drag racing section.
Every car is different but a good rule of thumb is you want a hard bound in the back with a slow rebound....you want the car to go up and stay up but you dont want it to just POP up you want the suspension to use the weight of the car to force the rearend down into the pavement and not up into the car..........as for the front you want a quick rebound but a hard bound.....so easy up but hard down........i run stock springs with drag bags in mine with a set of varishock chassisworks adj. shocks out back.......the back of my car is pretty stiff.....for me a bit stiffer works better because id dampens the hard shock of the drive train trying to jam the tires into the ground......helps to keep the tires loaded a bit.....
Old 12-20-2010, 12:20 PM
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^^^^ Same.

There should be SOME rear suspension squat, but it's hardly enough to see with your own eyes. The amount of suspension travel should equal the compression of the tire on the launch. With a drag radial, there isn't much, if any (seen in my videos).
Old 12-20-2010, 06:05 PM
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no point in trying to set up suspension on a street tire IMO. That's why it's pointless throwing LCAs and all that jazz on the car for most people. There will be no consistency there to judge whether your changes are effective or not.
Old 12-21-2010, 07:34 AM
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Originally Posted by Wicked94Z
no point in trying to set up suspension on a street tire IMO. That's why it's pointless throwing LCAs and all that jazz on the car for most people. There will be no consistency there to judge whether your changes are effective or not.
true the consistancy will not even be remotly close to a slick/drag radial however the correct geometry and setup will help........last year at the track on day i ran my car on pure street tires (i switched my slicks with a freind of mine for a pass).......i cut a 1.78 60' on a goodyear eagle f1 street tire and ran a 10.98 @ 129 on them (ran out of rpm on the high end cause of the height) .....roasting tire through 2nd but it did bite out of the hole.......so even with a street tire a properly set up suspension WILL help......but id invest in some DR's one way or another....
Old 12-22-2010, 12:52 AM
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torque arm made the most noticeable difference on my car. lca relocation brackets also made a noticeable difference. i built everything myself and saved a ton of money and learned a lot in the process. idk if you have access to the tools or not but just an idea

IMO subframes are a very good first investment.
Old 12-22-2010, 07:56 PM
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I would do subframe connectors first especially if you have a t-top car, personally I like the 3 point type like the SLP or the UMI then I would do tubular lcas and relocation brackets, torque arm, panhard bar, strut brace, springs & shocks then bigger sway bars for an all around car. Or if you're after something specific like drag or autox then setup the suspension accordingly.
By the way I have BMR lcas and torque arm for sale check my ad in the classifieds under non LS parts or pm me.
Old 12-22-2010, 08:24 PM
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Depends what you want to do with the car. For handling shocks is #1 since the stock shocks are absolutely horrible on these cars.. For drag strip tires is #1.



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