Tires vs. Gear question

[habu]

I did a quick search but I didn't see anything specific. If there is a good link with this discussion please post it and I'll read up there.

I've got the Whipple HO, manual, Clutchmasters Stage4 clutch, 3.55s and putting out around 475rwhp, give or take. (also CHE LCA & Relos & Aluminum driveshaft)

My DRs are the M&H 325/45x17s. Even though the tires are a little worn my 60' was a 1.80 and I don't spin them launching at 3500.

The driver mod aside and my best time has been a 8.13 @91.
My car is largely street as my daily driver with only occasional trips to the track, every couple of months or so. I'd probably race more if I had a spare car.

Would I be better served to go down to the 275 M&H tire or go to 3.73 or 3.90s ?

 

[don_w]

Keep the tires and change the gears. The 275s are the same 28" diameter as the 325s.

 

[Leo_06GT]

What about if he switched to a MT ET Drag Radial? That would give him a 26" diameter boosting his gear ratio to the equivlant of a 3.73 or better right?

 

[psfracer]

Go with 4.10s, keep the M&H 325's and leave at 4500 rpm.

 

[stkjock]

I'd try leaving harder, when I had 3.55s I could pull 1.8 60s with a 265/40/18 DR, those M&Hs are a much better tire IMHO.

I'd try to launch @ 4500 as Paul suggested and work up until you dont hook.

Also what pressure are u using @ the track?

 

[Freaknazty]

Keep the tires and change the gears. The 275s are the same 28" diameter as the 325s.

+1 swap the gears id either do 3.90's or 4.10's when i was n/a with 3.90's i could cut 1.8 60ft all day leaving at 3-35oo after the turbo 1.5-1.6 at 35oo(ish) you will cut even better because you will have instant boost off the line as where im basically still n/a maybe 1-2lbs. boost at most stick with the 325's and do gears then dump that hoe out the gate lol

 

[kleistang]

4.10s and a lottttt of practice.

 

[habu]

Thanks for the advice

Go with 4.10s, keep the M&H 325's and leave at 4500 rpm.

I'm concerned about 4.10s and street driving. It is almost too much for the street and I don't want to make the car un-enjoyable driving day-to-day.

at about 4K I spin the tires, so I backed it down to 3500. psi... I think I was at 16psi give or take.

Another thing, the tires are getting worn so I think a new set is in order soon, which is why I was wondering if I should stay with this size.

 

[stkjock]

ahh, well if they need replacement that is a different story.

 

[psfracer]

I don't know---I have been running 4.10s for 2 years with a 28 tall tire, and have driven literally thousands of miles on the street. They are perfectly streetable---trans temp stays at 174, water temp at 195, and rpm stays around 2900 rpm at 80 mph. 4.10s with a 28 tall tire is like a 3.90 gear with the stock tires.

 

[joedls]

My car has 4.10s with a 305/35-18 tire on the street. That is a 26.4" tire. I run a MT ET Street 26 X 11.5 X 17 at the track. That is a 26.5" tire. I would not go back to a higher gear. The 4.10s work beautifully for me.

 

[Charlie Sheen]

I don't know---I have been running 4.10s for 2 years with a 28 tall tire, and have driven literally thousands of miles on the street. They are perfectly streetable---trans temp stays at 174, water temp at 195, and rpm stays around 2900 rpm at 80 mph. 4.10s with a 28 tall tire is like a 3.90 gear with the stock tires.

Same here.

 

[don_w]

I don't know---I have been running 4.10s for 2 years with a 28 tall tire, and have driven literally thousands of miles on the street. They are perfectly streetable---trans temp stays at 174, water temp at 195, and rpm stays around 2900 rpm at 80 mph. 4.10s with a 28 tall tire is like a 3.90 gear with the stock tires.

The 4.10s work beautifully for me.

Same here.

+3... I've been running 4.10s since July 2005 (~43K miles), and I absolutely love them.

 

[07 Boss]

I don't know---I have been running 4.10s for 2 years with a 28 tall tire, and have driven literally thousands of miles on the street. They are perfectly streetable---trans temp stays at 174, water temp at 195, and rpm stays around 2900 rpm at 80 mph. 4.10s with a 28 tall tire is like a 3.90 gear with the stock tires.

So if I'm going to run a 29" (28.81" actually) tire and want 3.73's I should actually run a 3.90 ring and pinion.

 

[Freaknazty]

So if I'm going to run a 29" (28.81" actually) tire and want 3.73's I should actually run a 3.90 ring and pinion.

that'll be pretty close i think the 4.10's will actually put you closer to the 3.73's your looking for though

if i remember correctly a

28" tire with 3.90's = roughly 3.73's
26" tire with 3.90's = roughly 4.10's
so in turn a 29" tire with 4.10's should be close to 3.73's

 

[07 Boss]

that'll be pretty close i think the 4.10's will actually put you closer to the 3.73's your looking for though

if i remember correctly a

28" tire with 3.90's = roughly 3.73's
26" tire with 3.90's = roughly 4.10's
so in turn a 29" tire with 4.10's should be close to 3.73's

Does 1" in diameter make that much diff. Well I guess 1" diameter is 3.14156..." in circum. if I remember my grade school math. Just for confirmation, anyone else have the same formulas as freakynutz, or whatever?