Question about suspension
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10-03-2013, 05:17 PM
5th Gen Master Builder
Drives: Camaro Justice
Join Date: Jun 2007
Originally Posted by
Does suspension really help quarter mile times by a decent margin, or is all suspension work mostly for tracking the car? Not very familiar with all this.
This will help you get familiar
5th Gen Wheel Hop and Drag Race Setup
Setup is more important on an IRS than a traditional solid axle because there are so many more variables in an IRS. Now is a good time to talk about wheel hop.
The #1 source of wheel hop on a 5th Gen Camaro is found in the
bushes. That would be the reason Chevrolet upgrade the sub-frame bushes by partially filling the Noise Vibration and Harshness (NVH) voids starting with the 2012 5th Gen Vert. The OEM sub-frame bushes are still biased toward NVH concerns and not burn-outs, or performance at the drags or road course weekends. The NVH voided original or slightly improved OEM sub-frame bushes allow the entire IRS to shift side to side while under-load. This motion changes the dynamic alignment of your 5th Gen creating rear end steer, rear end step out and contributing to wheel hop
The #2 source of wheel hop, particularly on lowered Camaros is
. Too much negative camber places the load of launch primarily on the inside shoulder of the rear tire. Spinning an inch and a half strip of tire doesn't take much HP. Aligning your 5th Gen to less than -.5 degrees rear camber with a TOE IN .17 improves your drag launch by using 90% or more of your rear tires to put power down.
The #3 source of wheel hop is deflection in the toe link bushes. We are not talking about toe link arm deflection we are talking about bush squish in the arm. How do I know? Hard engineering data. When GM built the Leno Twin Turbo Camaro they were not satisfied with the handling. Jay's Camaro has a very aggressive set of wheels and tires that increase the load on the suspension. In speaking with some members of the build TEAM I suggested a couple of Pedders upgrades in addition to the Xa coilovers that were already installed at the Milford Proving Grounds. Being a structured and data driven company, the build TEAM decided they should measure and document the issues on a shaker.
You can see a Camaro on GM's Shaker Rig at 55 seconds in.
What were the results of Leno's car on the
? The data and data points belong to Chevrolet and GM. The EP1200 sub-frame inserts and EP7323 Toe Link Bushes may be on Mr. Leno's Camaro, but they belong to me.
The #4 source of wheel hop on a 5th Gen is the tie and tread compound. Check aorund the forum and see what happends with wheel hop when you run on drag rubber or shorter tires.
The #5 source of wheel hop is a combination of modest spring rate and a damper map biased a bit too much to ride comfort. We spent a long time working with Lingenfelter to develop a dedicated set of drag coilovers. The front coil rate is 4.5kg and the rear is 12kg. The front monotube has a longer stroke than stock. The rear monotube is a massive 52mm diameter unit that is maxed out for bound control. High RWHP Camaros with slicks bite so har the launch is violent. They compres the rear suspension so fast that it bounces off the bumpstops. Keep in mind this was measured using a well known set of brand-x coilovers on the LPE Black Pig. When we bolted on out of the box Pedders Supercars the Black Pig picked up 2/10ths in the 60'. After we tested, refined and tested and.... you get the idea the LPE Drag Coilovers delivered more than 3/10ths improvement in the 60'
The #6 source of wheel hop is related to side to side load distribution. The factory rear sway bar 2010 to 2011 is a 23mm hollow tube that mounts inboard close to the differential. It is a light weight bar by any measure. The 2012 FE4 features an improved sway bar mounting position that is close to the knuckle. This is a HUGE improvement in geometry and function. The ZL1 comes of the assembly line with a 28mm SOLID bar. The change in geometry coupled with the change in bar strength (GM is now using solid sway bars just like Pedders Camaro sway bars) more effectively distribute load on hard launch. Upgrading to OE Rear Lower Control Arms with the new FE4 / ZL1 sway bar mounting points and a ZL1 28mm solid rear bar will imporve your drag launch. If you are looking for even more improvement your ONLY option is Pedders new 2010 to 2011 ZL1 32mm solid rear bar complete with GM ZL1 Arms and Pedders Droplinks. If you have a 2012 all you'll need is the ZL1 Rear Sway Bar Upgrade.
The #7 source of wheel hop is driveline movement. Driveline twist or driveline torque is a mini-wheel-hop motion. Replacing the OEM NVH biased differential bushes is the first place to start. The front two differential bushes are under heavy load, but that load is dwarfed by the load that the rear differential bush carries. Our solution is the new
. The front two bushes are very high durometer urethane and the rear bush is machined Acetal for maximum control for optimized launches.
When you are serious about your 5th Gen performance on the drag strip your solutions are found at Pedders and Lingenfelter. If you get serious so do we. We provide special support to the LPE Black Pig and her support crew.
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