Pontiac GTO News **Lessons learned (page 19)**
05-10-2007, 11:46 AM
#521
Drives With Hands
Originally Posted by chirik
Yo, GTO owners have LS2 mods question.
My cousin thinking about picking one up and install K&N drop-in filter, Kooks long headers w/cats and Magnaflow exhaust. What would recommend as far as tuning.
Anything else (scratch suspension) in terms of simple bolt-ons? How much power (wheels) he can expect from above mods on AUTO?
My cousin thinking about picking one up and install K&N drop-in filter, Kooks long headers w/cats and Magnaflow exhaust. What would recommend as far as tuning.
Anything else (scratch suspension) in terms of simple bolt-ons? How much power (wheels) he can expect from above mods on AUTO?
05-14-2007, 03:14 PM
#523
Cruisin'
Join Date: May 2007
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Originally Posted by Maximized
Funny that you mention those cars. I've driven all of those cars, minus the SC400. Maybe since you aren't a drag racer you aren't launching the car hard.
-C5 Procharged (460whp): Wheel hop at the strip on street tires
-SRT10 Viper: Wheel hop present. Diff eventually exploded. I guess this happens to quite a few Viper owners at the drag strip, per my buddy.
-C5 Z06: I've driven both an 02 and 04 extensively. Both experienced wheel hop. Great track car though.
-CTS V: Very bad wheel hop. Car would wheel hop horrible on a quick shift into 2nd.
-545i: My dad's car. Yep wheel hop present.
-350Z: My brother has one and my buddy Brian has an APS Z. I've got video of him launching if you'd like to see the wheel hop.
Like I said, I've never driven an IRS RWD vehicle without wheel hop.
-C5 Procharged (460whp): Wheel hop at the strip on street tires
-SRT10 Viper: Wheel hop present. Diff eventually exploded. I guess this happens to quite a few Viper owners at the drag strip, per my buddy.
-C5 Z06: I've driven both an 02 and 04 extensively. Both experienced wheel hop. Great track car though.
-CTS V: Very bad wheel hop. Car would wheel hop horrible on a quick shift into 2nd.
-545i: My dad's car. Yep wheel hop present.
-350Z: My brother has one and my buddy Brian has an APS Z. I've got video of him launching if you'd like to see the wheel hop.
Like I said, I've never driven an IRS RWD vehicle without wheel hop.
Solution? Replace engine mount bushings, rear end bushings, and suspension bushings with firmer bushings, and run a tire with a softer sidewall.
Please note that all of the cars you listed above, with one exception I'll get to in a second, are targeted towards roadracing and/or autocrossing. As such, the tires they are equipped with are going to have very stiff sidewalls, because it aids in cornering. Side effect of a stiffer sidewall is amplifying wheelhop. Toss some DR's are slicks on, along with firmer bushings, and watch the wheelhop disappear.
The one exception in that list is the 545i. That car aims to have a very cushy luxury ride, and one of the things done to make that happen is equipping the car with fairly soft bushings.
05-14-2007, 11:38 PM
#524
Suzuka Master
Join Date: Mar 2002
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Originally Posted by outphase84
Wheelhop is easy to cure in any car. It occurs when suspension or drivetrain bushings are the weak point in rigidity. What happens is that the tires grip, and the bushings flex under the stress now being imparted on them. They flex until they hit their limit, at which point the tires snap loose, unload the tension on the bushings, and then begin to regain traction, and the bushings start to flex again.
Solution? Replace engine mount bushings, rear end bushings, and suspension bushings with firmer bushings, and run a tire with a softer sidewall.
Please note that all of the cars you listed above, with one exception I'll get to in a second, are targeted towards roadracing and/or autocrossing. As such, the tires they are equipped with are going to have very stiff sidewalls, because it aids in cornering. Side effect of a stiffer sidewall is amplifying wheelhop. Toss some DR's are slicks on, along with firmer bushings, and watch the wheelhop disappear.
The one exception in that list is the 545i. That car aims to have a very cushy luxury ride, and one of the things done to make that happen is equipping the car with fairly soft bushings.
Solution? Replace engine mount bushings, rear end bushings, and suspension bushings with firmer bushings, and run a tire with a softer sidewall.
Please note that all of the cars you listed above, with one exception I'll get to in a second, are targeted towards roadracing and/or autocrossing. As such, the tires they are equipped with are going to have very stiff sidewalls, because it aids in cornering. Side effect of a stiffer sidewall is amplifying wheelhop. Toss some DR's are slicks on, along with firmer bushings, and watch the wheelhop disappear.
The one exception in that list is the 545i. That car aims to have a very cushy luxury ride, and one of the things done to make that happen is equipping the car with fairly soft bushings.
05-15-2007, 12:26 AM
#525
Cruisin'
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Originally Posted by Maximized
If you are so smart, why aren't you tuning suspensions for a major automotive company? Wheel hop isn't easy to cure and there is no magic bullet. If your idea of curing wheel hop is running spherical bushings all around, well more power to you. Get ready for a ton of NVH and increased maintence.
Everything is a tradeoff in this game, there's no free meals. A manufacturer needs to find a good balance of comfort/reliability and performance. You yourself actually listed part of the cure-all for wheelhop: spherical bearings in all suspension parts instead of bushings. Solid engine/tranny mounts are the other part. See, it is an easy cure; the side effects, however, are very undesirable in a daily-driven car.
My current DSM is a great example. FWD dsm's are known to wheelhop quite violently. However, prothane bushings in all front suspension, prothane bushings in the engine/tranny mounts, and a solid rollstop combined with a rather firm suspension have completely eliminated wheelhop in my car. However, I will not drive my 11 month old son around in my car -- it's uncomfortable for me to drive, and would probably be painful to him.
05-15-2007, 05:54 PM
#526
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Originally Posted by outphase84
Everything is a tradeoff in this game, there's no free meals. A manufacturer needs to find a good balance of comfort/reliability and performance. You yourself actually listed part of the cure-all for wheelhop: spherical bearings in all suspension parts instead of bushings. Solid engine/tranny mounts are the other part. See, it is an easy cure; the side effects, however, are very undesirable in a daily-driven car.
My current DSM is a great example. FWD dsm's are known to wheelhop quite violently. However, prothane bushings in all front suspension, prothane bushings in the engine/tranny mounts, and a solid rollstop combined with a rather firm suspension have completely eliminated wheelhop in my car. However, I will not drive my 11 month old son around in my car -- it's uncomfortable for me to drive, and would probably be painful to him.
My current DSM is a great example. FWD dsm's are known to wheelhop quite violently. However, prothane bushings in all front suspension, prothane bushings in the engine/tranny mounts, and a solid rollstop combined with a rather firm suspension have completely eliminated wheelhop in my car. However, I will not drive my 11 month old son around in my car -- it's uncomfortable for me to drive, and would probably be painful to him.
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