2015 PP1 GT vs GT350 suspension differences

[nasaracer32]

Hey, I'm about to dive into a road course only track car project and it was suggested to "go with all GT350 suspension parts". I know there are some differences between the cars in terms of control arms and such, but does anyone have a quick reference list of part numbers?

I do have the part list sheet for the FPS350 cars that are built, so that helps but trying to aldo understand just how deep the differences go.....isn't just control arms and similar or is even the K-member/engine cradle mount different? Are the differences just in the front or also in the back?

The 2015 car being used is a PP1 car but obviously doesn't have Magnaride and it won't be built with it. Just asking about the suspension parts. Thanks in advance!

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[Roadsign]

enjoy the dive as it never ends lol
I believe the sway bars and springs are the only interchangeable parts between the two. There is a sticky with the spring part numbers. Don't remember exactly but there's something wonky about using the GT350 springs, use 2 of one side.

 

[NightmareMoon]

Well the knuckles are different geometry, the springs, swaybars, and the 350 has more bushing supports IIRC in the rear cradle. The 350s have magnaride shocks, which aren't reasonably something you can retrofit. Then the knuckles fit the larger brakes on the 350, etc etc.

Its not a gold standard for a track setup, as the springs and shocks are more street rates and while adequate (of course), for road course you can go a lot stiffer, and there are advantages in doing so. Depends on your goals.

For road course the car starts to really work with 500# front springs, and the 350 springs are a bit less than half that. I run 650# front springs on my autocross/track setup (500 is the starting point). That spring rate and above supports the front when you're trail braking into a corner.

Can you track a car with 200# or 250# front springs, of course you can! and if you're daily driving the car, you might not enjoy track spring rates on your daily driver.

So I wouldn't suggest you put the GT350 suspension on a pedestal. Its not cost effective to chase those parts as they key to performance. They're fine and the knuckle geometry is a good for slightly lowered cars, but there are more affordable ways to get that geometry (steeda sells some control arms which effectively do the same thing).

 

[NightmareMoon]

The GT350 brakes are nice for road course (the rears aren't the single piston caliper that the GT's have), although that single piston works, it overheats a bit too easily which cooks the rubber boots. They also force you to 19" or larger wheels, which may or may not be a downside.

 

[GrabberBargeCaptain]

Well the knuckles are different geometry, the springs, swaybars, and the 350 has more bushing supports IIRC in the rear cradle. The 350s have magnaride shocks, which aren't reasonably something you can retrofit. Then the knuckles fit the larger brakes on the 350, etc etc.

Its not a gold standard for a track setup, as the springs and shocks are more street rates and while adequate (of course), for road course you can go a lot stiffer, and there are advantages in doing so. Depends on your goals.

For road course the car starts to really work with 500# front springs, and the 350 springs are a bit less than half that. I run 650# front springs on my autocross/track setup (500 is the starting point). That spring rate and above supports the front when you're trail braking into a corner.

Can you track a car with 200# or 250# front springs, of course you can! and if you're daily driving the car, you might not enjoy track spring rates on your daily driver.

So I wouldn't suggest you put the GT350 suspension on a pedestal. Its not cost effective to chase those parts as they key to performance. They're fine and the knuckle geometry is a good for slightly lowered cars, but there are more affordable ways to get that geometry (steeda sells some control arms which effectively do the same thing).

Is the different front suspension geometry in place because the car is lower than a GT? Is it because of the wider track in the front?

 

[NightmareMoon]

Is the different front suspension geometry in place because the car is lower than a GT? Is it because of the wider track in the front?

just the lowering, I believe the track width is entirely from the wheel offsets.

 

[nasaracer32]

Thanks guys, good feedback here. Much appreciated!

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