Best DR size with 3.73 gears

[qwk93ta]

I'm currently running 275/40/17 Hoosier drag radials. I have a 13 GT with the GT performance package so I have 3.73 gears and a M6. I have a tune, CAI and a Roush axle back. I ran a best of 12.52 @ 110.63 with a 1.81 60' time leaving at 2,000 rpms. DA was about 450. I hit the rev limiter near the end of the track and my car takes a nose dive every time. (I have these DRs from my 15 GT PP that I sold last May because it had the vibration)

I want to go to a 15" rim. A 275/60/15 DR is 28" tall and a 295/65/15 DR is 30" tall....which one would be better??


Thanks, Mark

 

[redfirepearlgt]

You def don't need a 30" IMHO with that setup. A 28" should and will get you there. A 30 would be overkill and hurt you out of the hole. especially with the mods you are running. A 30 is on the edge of going big tire. Two options - a 17x9.5 rim with accommodating tire which I found fit better and allowed s slightly wider tire, but more expensive overall) or you can run a 15x8 with the 275/60/15. Either option will work without the need to do the relocation bracket kit. However that said in doing so you can run the 15x10 which works equally well with the 275/60/15 and have some wider wheel options for the rim as you add power down the road.

I have run the 17x9.5 with a 305/45/17 R series MT Radial on my setup as well as the 15x8 currently with the 275/60/15 setup. The former gave me a slightly better ET, but it seems the 15 with the taller sidewall has given me a little more consistency which beats blowing them off one pass and running a solid 60 the next pass.

Just curious, where does the tune have your rev limiter set? Do you not have access to raise it in the tune if it is set close to factory for some reason?

 

[Grabber Blue 5.0]

You need a slick, not a radial with your manual transmission. Do it right.

 

[qwk93ta]

The rev limiter is set at 7,200.

 

[redfirepearlgt]

The rev limiter is set at 7,200.

kick that rev limiter up to 7600 and shift at 7300-7500. You'll be fine.

As for the tire type now that its been brought up, I do suggest a bias ply tire for the setup in a 28. THe R series MT bias tire is doing very well fora friend of mine who puts down 750 @ the wheel and cut's 1.4 60's on them.

So go with the 28, run a bias ply version of a DR (The MT ET street R or comparable in a Hoosier or other brand works nicely as well) and open that rev limiter up top a bit more. You should be able to find a 1.7x with a manual on a bias ply and a 3.73 when it's hooking right. Will take some time but you'll get there. Should you start having some wheel hop, upgrade the Upper control arm. AND for the record the 13/14 GT manual came with the GT500 LCA's on it stock so those are fine for your setup IMO on what you have currently.

Good luck

 

[qwk93ta]

Thanks.

 

[redfirepearlgt]

Thanks.

Just keep in mind if you plan to run the car on the street with a DR setup it may be advisable to go with a radial for purposes of staying with a radial on the front and rear for safety purposes. That's not to say people don't run bias ply rear and radial front, on their cars on the street and find no issues with doing so. Otherwise swap tires at the track. Best of luck to you.

 

[qwk93ta]

I'll only have the DRs on the car to and from the track....that's all the street use they'll get.

 

[skaarlaj]

Hoosier qtp's work good, are featherweight, and are dot legal, but wear unbelievably quick.

 

[qwk93ta]

Hoosier qtp's work good, are featherweight, and are dot legal, but wear unbelievably quick.

I agree....I had the QTPs on my 2000 TA I drag raced many years ago. With pretty much the same RWHP as my GT I could cut 1.6x 60' times.

 

[skaarlaj]

I agree....I had the QTPs on my 2000 TA I drag raced many years ago. With pretty much the same RWHP as my GT I could cut 1.6x 60' times.

I also used them to and from the track I use that is 100 miles away, and they drove just fine with about 28 psi in them for keeping heat out of the sidewalls, stability was never an issue at lower pressures.