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Registered GTO Abuser
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Discussion Starter #1
my father and i have had a long string of vettes come through the house hold and i have a few ideas about this wheel hop curse we are all plagued with

on the 70 that we have we did a conversion that relocated the diff just about an inch and a half to two inches lower in the car effectivly causing the half shafts to become more paralell to the ground, in stock trim the halfshafts have a downward angle towards the the trailing arms or spindles in our cases and under extreme accel (ie launch on the strip) the suspension goes downward and outward in a kind of snap like motion due to the tires traveling in an arc as the suspension compresses and decompresses causing the tires to loose traction on the surface. by lowering the diff you change the movement of the tires and suspension throughout their travel now the tires dont arc because they are past that step in their travel because of the half shaft angle

if i can illl try to dig up the article on the kit and this might give a better look into how it works
 

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TWO-TONS-OF-FUN said:
my father and i have had a long string of vettes come through the house hold and i have a few ideas about this wheel hop curse we are all plagued with

on the 70 that we have we did a conversion that relocated the diff just about an inch and a half to two inches lower in the car effectivly causing the half shafts to become more paralell to the ground, in stock trim the halfshafts have a downward angle towards the the trailing arms or spindles in our cases and under extreme accel (ie launch on the strip) the suspension goes downward and outward in a kind of snap like motion due to the tires traveling in an arc as the suspension compresses and decompresses causing the tires to loose traction on the surface. by lowering the diff you change the movement of the tires and suspension throughout their travel now the tires dont arc because they are past that step in their travel because of the half shaft angle

if i can illl try to dig up the article on the kit and this might give a better look into how it works
Thats cool but how about two bottles of NOS in the trunk for weight and traction :sneaky:
 

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Mod Hungry... Empty Wallet
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Holeshot said:
Thats cool but how about two bottles of NOS in the trunk for weight and traction :sneaky:
:gr_jest: you are evil :gr_jest:
 

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I like boobs.
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At the very least, making the angle more flat between the diff and the wheel would lower the amount of stress on the CV joints under extreme loads. (IE: Hard launches.)

I'm wondering if A4's have less wheel hop than M6 due to the fact they preload the rear which squats it down some to begin with? Anyone with an A4 care to chime in regarding wheel hop?
 

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Maybe this is straying off topic a little bit but I had a question about the rearend squating. Is this a characteristic of an IRS loading up? I saw in a couple videos of the BMR GTO launching that the rearend squated. I thought it was *bad* in drag racing for a car to squat like that. I've seen videos of GN's and F-bodies where the rear of the car actually rises when they get ready to launch. It's the axle pushing against the chassis through the torque arm. Is it different for an IRS?
 

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I like boobs.
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Weight transfer to the rear on a rear wheel drive car helps traction. The rear 'rise' on a very fast car you may be thinking of may be the tires growing as they launch which in turn rises the rear end.
 

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Anti-squat is designed into a suspension. Squat is controlled by the angles formed by the suspension pickup points on the chassis. For a semi-trailing arm setup like the rear of the GTO, moving the inner/rearward pickup points down, or the outer/forward ones up (or some combination of the two) would increase anti-squat.

The corollary for the front end is anti-dive. When you step on the brakes the front end wants to drop due to the forward weight transfer. By tuning the angle of the pickup points for the control arms the dive can be reduced or eliminated. You essentially make the forward motion of the car jack the front end up.

It is measured as a percentage of “anti” force for a given amount of actual force. So, if a weight transfer was trying to move 100 lbs to the rear of the car, and the suspension geometry had 50% anti-squat, 50 lb of force would push up against the chassis rather than down against the springs. This does not change the weight on the wheels, just whether the weight is applied through the springs or the control arms. Anti-squat is typically good for drag racing, bad for road racing.

For drag racing, the lift associated with more than 100% anti-squat raises the roll center of the rear axle, meaning the weight transfer to the rear operates through a larger lever, increasing “bite” at launch.

For road racing, raising the roll center means more body lean in a corner and unloading of the inside tire.

I think the GTO is tuned more for the road than drag racing.
 

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CAUTION!!!!
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well concidering that the GTO drifting car, isnt too far away from stock, id tend to agree that this car is set up for road courses....
 

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The Anti Dyno Racer
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The IRS on a '70 Vette is completely different than the new GTO. On the Vette, there is only 2 trailing arms, attacked to the frame behind driver and passenger. There are two lower links from the bottom of the spindle to the rearend housing, and the halfshafts are the upper links. The halfshafts, being a load bearing member, will affect the suspension squat and arc relative to the angle. The GTO uses CV style shafts to the wheels, so there will be no benefit to changing halfshaft angles. Use a higher durometer bushing in the rear control arms, a stiffer swaybar and change rear spring rates. Wheelhop will be reduced, as well as an increase in traction. The C5 guys have already done our homework on this, and I 60 footed 1.52-1.55 at the track on a stock suspension in my C5.
 

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May I quote you on that?
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SLP has some swaybar and link bushings, but has anyone done the control arm bushings yet?
 
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