New GT500 owner with questions

Truthfully, you're looking more at about 110hp at the crank. Everything is relative to who did the testing where it was conducted, what dyno and which system. Not all testing is the same and performance parts are not all equal. There are nice gains to be had but you have to be picky with the parts and tuner used. Dyno testing is always a must! A tuner will put you in the ball park but dyno tuning will bring the most from the parts.

 

First, fix the suspension and make use of the horsepower you already have.

 

Hello from NJ!

I'm not big into performace mods, but this I can tell you from my own experience... There's a lot of juice on tap with these monsters right from the factory. Getting the power to the ground is what I see as job #1. If I were to do anything to my ride, it would be stickier / wider tires in the rear. You know you need better tires when it takes almost nothing to get them spinning in 3rd gear.

 

The suspension isn't that bad but can be enhanced greatly with a Fays2 Watts Link. Most of the problems with handling lend itself to over steer caused by the rear end stepping out of line with the front wheels. This is generally caused by movement of the rear end in the chassis. The panhard rod just doesn't secure it in place as well. In effect you get slight movement in the rod in the form of flexing under G-load. The chassis moves on the rear suspension and exacerbates the problem. With a solid axle and more moving weight at the rear, in slalom type and heavy G-load turns the axle is trying to catch up with the front. The nearest example would be to look at a snake moving. Of course not in general sense but similar. Securing the rear end in the chassis and eliminating and side to side movement greatly improves the turning and straight line handling at speed. The Fays2 Watts link does this superbly. You immediately notice the rear wheels follow the front into cornering without the tendency of wanting to take there own track. Suspension feels firmer and more controllable because the side to side movement of the rear axle is eliminated. It also stabilizes the tendency for body roll.

Yes, I agree you can always improve on a suspension but before you sink several thousands in new suspension components you first have to eliminate the weak link in the suspension. The Fays2 Watts Link is around $650 and is the best start in solving those problems. There are draw backs with upgraded suspension components. Rougher handling, increased chassis noise, non-compliant chassis movement, improperly adjusted components for road surfaces and the ever increasing tendency to bump steer.

All the suspension components must work in unison like an orchestra to realize the benefits. If you replace the shocks you have to replace springs. Then you have to make the chassis stiffer. After making the chassis stiffer, then you have to improve on body roll by adding stiffer adjustable chassis components, to get the real benefit of the shocks and so on. So it becomes a very expensive proposition when you really should have fixed the problems first. This is not to say these suspension components won't make a difference, they will. It's always best to start with the inherent problems first before you cause or increase them.

So you can start with the suspension component modifications and never realize the all the benefits first. Or you can choose to make minor fixes to the problems and realize major benefits with your current setup and preclude them before you drop thousands into creating or exacerbating more.

Most of you will never be able to take the car to it's limits and beyond, unless you track the car. Which means you shouldn't be testing it's capability on public roads It's not the place for such activity. If you do track the car, remember you risk damage to expensive stock components that aren't track and high speed compliant. Be wise in your upgrades and you may realize the potential of the components which are already in place for a whole lot less.

Eitherway, enjoy your GT500 and the modifications you intend to make but remember there are particular consequences you must contend with. HAPPY MODIFYING!

Cheers

Jeffafa

 

Wider doesn't always mean better handling. Sticker doesn't always mean better performance. Wider tires require wider rims to accommodate the added width which can reduce the fit in the wheel well and give you allot more rolling mass. This can reduce fuel economy, increase maintenance, and actually hurts overall performance. Certain tire and wheel combinations are available. As you increase the size of the tire to say 19's or 20's you increase the rolling mass greatly. This requires more horsepower compared to the stock 18's. As you reduce the height of sidewall you also cause additional load on the suspension components. You loose some of the sidewall flexing which can cause additional load on stock panhard rods, shocks and sway bars which can cause other handling problems. You also need to change the ratio of the speedometer by way of a tuner to get the right Speedo reading.

Sticker "R" compound tires lend themselves to accelerated wear and are generally much more expensive then street rated compounds. They wear uneven, chassis and suspension strengthening modifications are needed to handle the increased load correctly.

So wider and sticker aren't always better. In the end you have to decide what you really want. A low and slower custom look or a performance enhanced street compliant hotrod or somewhere in between.

Cheers

Jeffafa

 

Hey Jeffafa,

I was just thinking in terms of straight line 1/4 mile runs! That's what I automatically focus on, lol!

 

Man you need to be more specific. Try a set of Nitto N03 Drag Radials. You'll need to play with the tire pressure a bit. Start at about 25lbs. Watch out for that GT500 clutch though. I've seen people think the were spinning up the tires in third and later found out they were burning up their clutch. The diameter and sidewall of the tire still matters though. 19's and 20's won't give you good straightline performance. Stick with the 18's and if you can get a set of Centerline 15's for the rear your still better off. You may have to check the disc clearence though.