If you're gonna do those tires, then just do the Brenspeed package with tires and factory 17x8s.

 

I went through two sets of 26" MT ET Streets on the factory 17x8" wheels when I was sitting at 300hp and with 4.10s. When my hp was up a round 323, I bought a set of 17x9" wheels and used the MT ET Street Radial 295/45-17 (27" diameter). After a few more mods and 348hp, I got an easy 12.67 ET that crunched the BMR LCA relocation bracket and dug a nice gouge in one of the drag radials. The 295s are on national backorder, so I'm trying a 28" tall tire for the first time: M&H 325/45-17. There is a point where HP will overcome the extra rolling resistence, but I'll just have to see if I'm there. I've still got my set of 17x8s with the ET Streets. If I can I'll compare the 26" and 28" tires on the same day.

John

 

Basically it all depends on what gear you wanna go through the traps in. With your setup your effective gearing with a 26in tall tire and a 3.73 rear gear is a about 3.90 effective gear and is probably forcing you to shift in to fourth gear just before the traps if you are still n/a. This isn't good for your et's or mph trap speed. If you had a stock overall diameter tire (27.2in) with that 3.73 rear gear, you could safely hold third gear through the traps,assuming your 1/4 mile trap speeds are in the 107-108 range. Your rpm's would be about 6500-6600 as you cross the line. Whatever gear you go through the traps in either 3rd or 4th gear just try use all of that gear if you can. This is why i want a shorter overall diameter tire (26in) with my 4.10 rear gear setup so i can effectivley increase my gearing to a 4.30. This way i can use more of 4th gear during the run so my rpm's at finish will be higher. I hope this explanation helps you some.

 

My 1/4 mile times and mph were better with the stock 3.55 gears, because i was able to hold third through the trap. Since changing to 4.10's the extra shift and the lower rpms I go through the traps in are slightly huting my et's and mph. Hopefully my cure for this will be shorter diameter tires in the rear, so i will have even more effective gear and the 4th gear shift comes alot sooner in the run versus later in the run.

 

so to hijack this thread....

I've got 3.55s and have the Whipple, should I get the 28" 325/45-17 tire ?

Last I raced was with Leo @ Qualcomm on the stock tires and NA and it was a joke. I knew then I need DRs at the least but wanted to wait until I got the Whipple. I have since added an Aluminum DS and CHE LCAs & Relo brackets as well

Thanks.

 

I think I'm finally getting it, thanks, I knew that the RPM I was hitting wasn't as efficient as it could be. Now I have to start thinking about new DR's, if I can go smaller than I can be in 4th because it will hit sooner (and yes, my automatic shifts to 4th just before the traps) and I can then efficiently use 4th - if I go bigger DR's than I can hit the traps in 3rd and be using third more efficiently. Right now if I try to hold it in 3rd I run out of gear before the traps and hit the rev limiter.

 

If you guys are racing 1/8 mile tracks, I would stay with a 275 tire. If you're doing full 1/4 mile, you might try the 325.

 

1/8th for Irwindale, which is what I'd likely most run at... There is Barona and Fontana I have no idea what they are

Thanks for the advise. I think, if I sell the Bullitts, I might use the gov't refund for the Brenspeed deal....

 

I would've but I wanted the ET Street Radials and they only offer the ET Streets. Plus I got a killer deal on my ET Street radials.

Barona is 1/8th mile Fontana is a 1/4. Call me sometime and I'll give you a few reasons why you should go with the street radial.


BTW-
Here's some pics of the MT ET Street Radials I picked up yesterday. Got'em both brand new for $300 of Craigslist. Can't beat that. Now just looking for a killer deal on some 17x8 takeoffs.

 

Nice!