3.31 and 3.55 gear question
- Thread starter Randy 25
- Start date
SpartaPerformance
10 Year Member
ptfoxbdy89
New Member
Sparty92
Member
Sparty92 thanks, that's what I was looking for. I maybe should make myself a little clearer. I'm looking at buying a GT and was looking at axle ratios. I've had from 2.72s to 4.11s in cars over the years. I have an 04 F150 with 3.55 and run around 2000 rpm at 70. I was hoping that with smaller tires on a stang, that the rpms would be a bit higher than what Sparty 92 is reporting. Maybe a good all around ratio is 3.73. I drove coast to coast a couple of times in a vette many many years ago with 4.11s and it bout did in the engine. Can anybody chime in with what 4.73s do rpm-wise at 70 mph in 5th gear? Tx.
SlideWRX
Member
At 70 mph, the 3.31 is 1,990-2,015 rpm, the 3.55 will be 2,135-2,160 rpm and the 3.73 will be 2,240-2,275. Pulled from a spreadsheet I threw together at one point. Assumes 768 rev/mile on the tire, pulled from the specs for the OEM 17" Pirelli on the tirerack.com site.
Sparty92
Member
Since my tach (and probably yours) shows increments of 250 rpms, you can assume +/- 250 rpm for any of the aforementioned gear ratios.
I find the 3.55s and a 5-speed to be fairly zippy. Lots of guys that drive cough...automatics...cough....swear by 4.10s. I would think that 1st gear would be really short in a manual trans car. I drive my car daily, year round. If you're a drag strip freak, 4.10s would be something to consider. I would opt for 3.73s myself. If Ford can stuff them into a Bullitt, it HAS to be safe for freeway driving....right?
I "think" you can get 3.73s in the 2010 Mustang...as an option. If not, gear swaps are fairly cheap...I was quoted $500 parts and labor...which I find "do-able."
Good luck!
garbledwords
Member
Attached is a Excel spread sheet that I found on-line someplace that lets you calc the rpms for different gears. For both transmission and rear gears.
Hmm.. It would seem that I can't upload a .xls file. I simply renamed the file to have a .txt extension so just rename it gears.xls and you will be all set.
Hmm.. It would seem that I can't upload a .xls file. I simply renamed the file to have a .txt extension so just rename it gears.xls and you will be all set.
GreyDiesel
New Member
Not to hijack this thread but...I have a set of original 3.55 gears with less than 3000 miles on 'em...will sell at 75% off the price new...send me an email if you're interested -
[email protected]
[email protected]
08blueskunk
New Member
my old 97 Cobra Had the 3.73's and it was all together different from my 3.31's now, very snappy it got about 19mpg and my 2008 bone stock gets about 23 MPG. That would be my daily driver choice i think...3.73's
Similar threads
