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This post is really directed at new F-body owners, as the long time "pros" probably already know this. I just wanted to share my experience while its still fresh in my mind.
If you recall, last summer I bought this 98 Firebird V6 auto with just 28k miles. Owned by an older couple and garage kept, I figured it was in great condition. For the most part it is, but as it turns out the rear needed some work.
I didn't like the way the car handled some rough concrete highway that was poorly patched with black top. Hitting this 2 mile stretch made me wince as the car would act squirrely and didn't seem to follow the surface well. After having the 3.73's and Truetrac installed, things seemed to be even worse. Peel-outs gave way to severe wheel hop. Rough pavement was even worse, especially when accelerating or on turns. I was getting angry that I couldn't do measure 0-60 times due to bad wheel hop.
First, larger rear sway bars were installed. 30mm front and later, a 19 mm rear, using poly bushings and end links all around. (OE is 28/15 mm on my base coupe) The front bar was a fantastic upgrade. The rear bar caused such bad oversteer I nearly crashed the car on an exit ramp. So the OE 15 mm bar went back in, but I kept the poly end links. That was a good thing. The car handled much better with the poly. So far, so good, handling much improved. Did nothing for wheel hop. Bars were free, but the poly bushings and end links ran about $40 or so. Best price on Energy Suspension parts I found was at Advance Auto. Call the local store, they will order the parts and you pay the online price, and you save shipping.
In an attempt to stop the wheel hop, new KYB GR2 rear shocks (a mild twin tube design upgrade over the factory shock) were installed by yours truly. I allocated about 2 hours, but it only took about 1.5 hours start to cleanup. This made a big change. I never would have thought that the OE Decarbon rear shocks were shot after (now) less than 40K miles. The rear now follows even rough pavement well, even at highway speeds. Rough pavement on exit ramps is not a problem. The back end stays where it should, and interior noise is greatly reduced. Also a funny "bonk" sound that would happen on big bumps is gone. Guess the shocks were much worse than I suspected. Surprisingly the Decarbon shocks were still holding their gas pressure when they were removed, so the failure was probably in the valving/piston, rather than foaming oil. Really great improvement, and all for about $40 for a pair of rear shocks. Downside is the wheel hop was reduced, but it was still there.
Next suspension upgrade was specifically to stop wheel hop. The two piece OE rubber torque arm bushing was replaced with an Energy Suspension one piece bushing. The E/S piece is poly, harder than rubber, but not as hard as the poly used in the end links or sway bar bushings. The bushing can be changed without lowering the trans, but space is tight, and it just takes patience and time to remove the single nut and chisel or grind off the riveted on OE bushing. I used a small 4" die grinder to remove the rivet on the trans mount. Tight fit, but do-able without messing up other parts. The other half comes out and can be worked on in a vice. After its all buttoned up, I was really surprised at how tight the rear felt. Funny road noise was reduced, and again, wheel hop seemed better, but still not totally gone. The OE two piece bushing, although not chewed up, appeared to have spread open, allowing the T/A movement. With the new bushing, the T/A is held tight. Funny "ringing" noises from the new rear gears were gone after installing the new bushing. Guy who did the rear said that the T/A resonates noise from the rear, making a quiet rear hard in these cars. So, again, car handles better, rough pavement is even better and quieter. Another cheap (about $14) upgrade that actually makes a difference.
So now most of the rear parts have been replaced, and wheel hop is still present. I read where the rear control arm bushings are "hollow" or star shaped when viewed from the side for compliance and quiet ride. You can not tell what is on the car by looking. A common upgrade is to use poly bushings. I will not install poly bushings because this is a daily driver, and the poly often cause the control arm mounts to crack and fail because they are so stiff. So solid rubber bushings will be used, like on the LS1 suspension. Going to pick up a set of used LCA's that have been boxed to make them stiffer, and have solid rubber bushings to allow for flex. Hopefully this will be the final "nail in the coffin" of wheel hop, and I will be able to get a decent 0-60 time.
Will keep you posted.
Mark.
PS. All the changes, shocks, sway bars, and T/A bushing were done in my garage using only a small floor jack and two heavy duty jack stands. Other than a cheap-o Harbor Freight 4" die grinder (and you can substitute a sharp chisel and hammer), all tools were just basic box end wrenches and sockets. Just be safe and use good jack stands and wheel chocks.
If you recall, last summer I bought this 98 Firebird V6 auto with just 28k miles. Owned by an older couple and garage kept, I figured it was in great condition. For the most part it is, but as it turns out the rear needed some work.
I didn't like the way the car handled some rough concrete highway that was poorly patched with black top. Hitting this 2 mile stretch made me wince as the car would act squirrely and didn't seem to follow the surface well. After having the 3.73's and Truetrac installed, things seemed to be even worse. Peel-outs gave way to severe wheel hop. Rough pavement was even worse, especially when accelerating or on turns. I was getting angry that I couldn't do measure 0-60 times due to bad wheel hop.
First, larger rear sway bars were installed. 30mm front and later, a 19 mm rear, using poly bushings and end links all around. (OE is 28/15 mm on my base coupe) The front bar was a fantastic upgrade. The rear bar caused such bad oversteer I nearly crashed the car on an exit ramp. So the OE 15 mm bar went back in, but I kept the poly end links. That was a good thing. The car handled much better with the poly. So far, so good, handling much improved. Did nothing for wheel hop. Bars were free, but the poly bushings and end links ran about $40 or so. Best price on Energy Suspension parts I found was at Advance Auto. Call the local store, they will order the parts and you pay the online price, and you save shipping.
In an attempt to stop the wheel hop, new KYB GR2 rear shocks (a mild twin tube design upgrade over the factory shock) were installed by yours truly. I allocated about 2 hours, but it only took about 1.5 hours start to cleanup. This made a big change. I never would have thought that the OE Decarbon rear shocks were shot after (now) less than 40K miles. The rear now follows even rough pavement well, even at highway speeds. Rough pavement on exit ramps is not a problem. The back end stays where it should, and interior noise is greatly reduced. Also a funny "bonk" sound that would happen on big bumps is gone. Guess the shocks were much worse than I suspected. Surprisingly the Decarbon shocks were still holding their gas pressure when they were removed, so the failure was probably in the valving/piston, rather than foaming oil. Really great improvement, and all for about $40 for a pair of rear shocks. Downside is the wheel hop was reduced, but it was still there.
Next suspension upgrade was specifically to stop wheel hop. The two piece OE rubber torque arm bushing was replaced with an Energy Suspension one piece bushing. The E/S piece is poly, harder than rubber, but not as hard as the poly used in the end links or sway bar bushings. The bushing can be changed without lowering the trans, but space is tight, and it just takes patience and time to remove the single nut and chisel or grind off the riveted on OE bushing. I used a small 4" die grinder to remove the rivet on the trans mount. Tight fit, but do-able without messing up other parts. The other half comes out and can be worked on in a vice. After its all buttoned up, I was really surprised at how tight the rear felt. Funny road noise was reduced, and again, wheel hop seemed better, but still not totally gone. The OE two piece bushing, although not chewed up, appeared to have spread open, allowing the T/A movement. With the new bushing, the T/A is held tight. Funny "ringing" noises from the new rear gears were gone after installing the new bushing. Guy who did the rear said that the T/A resonates noise from the rear, making a quiet rear hard in these cars. So, again, car handles better, rough pavement is even better and quieter. Another cheap (about $14) upgrade that actually makes a difference.
So now most of the rear parts have been replaced, and wheel hop is still present. I read where the rear control arm bushings are "hollow" or star shaped when viewed from the side for compliance and quiet ride. You can not tell what is on the car by looking. A common upgrade is to use poly bushings. I will not install poly bushings because this is a daily driver, and the poly often cause the control arm mounts to crack and fail because they are so stiff. So solid rubber bushings will be used, like on the LS1 suspension. Going to pick up a set of used LCA's that have been boxed to make them stiffer, and have solid rubber bushings to allow for flex. Hopefully this will be the final "nail in the coffin" of wheel hop, and I will be able to get a decent 0-60 time.
Will keep you posted.
Mark.
PS. All the changes, shocks, sway bars, and T/A bushing were done in my garage using only a small floor jack and two heavy duty jack stands. Other than a cheap-o Harbor Freight 4" die grinder (and you can substitute a sharp chisel and hammer), all tools were just basic box end wrenches and sockets. Just be safe and use good jack stands and wheel chocks.
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