Nichles3

Would this square setup be possible, 17x9.5 38 et 285/40-17 tires? I know 17s are considered small but they are lighter and tires are less expensive. Smaller diameter should give you better performance. Probably going to be lowered on coilovers, nothing crazy low. Looking for the best overall performance.

PureDrifter

iTrader: (10)

balloon tires man, going to be mad squishy if you actually start pushing it. If you want to drive hard (i'm guessing with the wider tires) you'll be wanting 18s at least.

285 is too wide for a 9.5" rim, you'll be wanting a 10" rim at least. should be doable in the front depending on how wide you are, but not with anything under +40 offset without solid fender work.

RA40

iTrader: (6)

You may save some weight with a smaller wheel but tire weight goes up and some can be pretty heavy. If you desire the suspension to feel lively, keeping the combo less than 52#'s in the goal.

Nichles3

The roads here in Mass are crap. Was thinking a 285 would have a decent sidewalk and not a rubber band. Plus it is closer to the stock tire diameter. 285 is still within spec on a 9.5 wheel. Maybe 275 front and 285 rear. With coils and same size tires front rear do these cars push or oversteer? Or would a staggered setup neutralize the handling? I figure with the right tire & suspension setup these cars can handle very well. They are very similar in size to current cts-v, g8, or 5 series bmws. And weight wise the LS is a lot lighter.

PureDrifter

iTrader: (10)

except suspension geometry on those cars you listed is setup a LOT more aggressively. TIres alone won't make your LS handle like a sports sedan, especially not 17s. (all those vehicles listed come with 18s at minimum).

the width won't affect the sidewall the way you seem to think, 2 tires will have the same sidewall height if they are the same rim size and same outside diameter, regardless of width. The aspect ratio decrease as width increases to ensure this.

The LS is setup from factory to be on the understeery side, especially in low-speed cornering. Staggered wheels/tires will exacerbate this. You need some solid suspension work to get these cars neutral.

Shmee

iTrader: (3)

You are best to not try and dial in or out certain handling characteristics with tires. Always start with the suspension because you can get more predictability out of a good suspension setup then with tires alone.

That said, the max tire size also depends on drop, fender work and what you want to do with the car. Iirc, you wanted to drop in an LSx, was this going to be a street car, track car or drift car?

If you are looking at drift, you are probably going to have to virtue out the tire sizing once you get your suspension setup and your wheels picked out. What could work in normal conditions on the street could be hitting the frame/fender/knuckle when drifting...

Nichles3

This is going to be a street car 99% of the time. I might on occasion go to a track day all in fun. Not really into the whole drifting thing. I was only referencing those other cars for dimensions only. I have full intentions of throwing the LS1 T-56 I have sitting in my garage into the car.

What I am really looking for is the best set-up to dial the car in to have neutral handling. I no this will never be a Miata. Just would like it to be a fun car to blast down some twist back roads. Having driven a few LS's now on my quest to find the right car. The steering is very light and the front end feels lazy. I guess I am looking to have the front end be a bit more responsive. Sharpen up the turn in a tad.

Shmee

iTrader: (3)

There is a lot that can be done.
Granted this car is a big comfy boat and 99.99% of people buying them are not looking to build it into a miata.
With all the adjustable suspension parts now available, and the sheer flexibility of the suspensions on these cars, you should be able to dial in whatever characteristics you want with a good alignment on the right parts. One limiting factor is the swaybars. The from bar is massive compared the the rear bar, and the rear sort of snakes it's way through the rear subframe. You could probably get creative and build a custom adjustable blade style rear swaybar, but you would have to be mindful of clearance to the exhaust and such.

I'm strictly speaking from years of modifying and building race cars, not from first hand experience of doing it with this car. But I am confident that with the right choice of parts and a good setup you could make these cars very nuetral and lively! With an LS1 and a T56, it would be even more fun!

PureDrifter

iTrader: (10)

-buy coilovers after you do your swap otherwise you'll need to respring/revalve afterwards as I'm guessing a not insignificant shift in weight.
-front rca
-rear lca+traction rods
-dial in about the same level of camber front/rear (instead of more rear as you will naturally get)
-likely need a bigger rear bar (custom)
-18/19" tires, something reasonably sticky.
-corner balance/align.