I recently supercharged my 2007 Shelby GT with a Paxton Novi 2200 SL, meaning power went up from 325 to approx 540hp. Wonderful results, but in 1st and 2nd I'm all over the place with zero traction and lots of smoke, sometimes also in 3rd. I want to change tires (on 18 inch torque thrust rims) and possibly fit on an LSD to increase traction. Any comments on recommended size tires would be sincerely appreciated (i'm thinking 275s if they fit on SGT rims), as would advice about the difference an LSD would make (and where I could buy one...) Thanks in advance!!

 

I run 315/35/17's and still have traction problems.

Try posting your question in the 05-2010 section.

 

I recently supercharged my 2007 Shelby GT with a Paxton Novi 2200 SL, meaning power went up from 325 to approx 540hp. Wonderful results, but in 1st and 2nd I'm all over the place with zero traction and lots of smoke, sometimes also in 3rd. I want to change tires (on 18 inch torque thrust rims) and possibly fit on an LSD to increase traction. Any comments on recommended size tires would be much appreciated (i'm thinking 275s if they fit on SGT rims), as would any advice about the difference an LSD would make (and where I could purchase one...) Thanks in advance!!

 

275 = slip that's not even near how much tire you need. Ferrari puts 275 tires on for 400 horsepower with the exact same weight over the rear wheels.

You need at least a 295, Shelby GT500s put on 285 with less horsepower and more weight over the rear wheels.

Also you already have an LSD. I'd start by getting wider wheels first, at least 10" if not 10.5" rears or ask around about having your existing wheels modified to be wider. Your fronts may need to be wider too or you'll experience snap oversteer when cornering if you go above 30mm wider front to rear on a 53/47 weight distribution car.

 

Not having traction is a ton of fun no doubt. But after awhile you want to control that power. This is best accomplished with wider rims/tires and relocation brackets. You can get some 9.5-10'' rear rims and (what I'd suggest) Nitto NT555R Drag Radials 305/35 series for about $500 per wheel. This is what's required to get traction with your hp numbers.

Not cheap, but rims/tires/relocation brackets are your only solution. I only have 337 whp and couldn't do anything w/o 305's and relocation brackets. I finally have suitable traction.

 

And you already have an LSD in the GT.. maybe you would want a gear type diff like I have in the detroit trutrac. Makes quite a difference.

 

duplicate threads were merged and in the S197 handling section

 

I don't think you can fit 275's on the 18" stock Bullitts. You have the stock 235's? I don;t think they recommend even 255's.

Go with the wider wheels, like 10", and stickier rubber along with the suspension upgrades.