WHICH GEAR TO PUT IN MY 05 GT? 3.73 OR 3.90 OR 4.10
08-26-2006, 10:16 AM
#11
3rd Gear Member
Thread Starter
Join Date: Aug 2006
Location: Michigan
Posts: 606
RE: WHICH GEAR TO PUT IN MY 05 GT? 3.73 OR 3.90 OR 4.10
YEA GUYS I HAVE A MANUAL, GETTING READY TO GET BETTER TIRES ALSO, BUT USE IT AS KIND OF A DAILY DRIVER BUT IT IS PARKED NOV-MAR (MICHIGAN WEATHER) DRIVE SOME HIGHWAY SO WAS WONDERING IF THE 4.10 WAS TOO BIG? I HAVE HEARD 4.10 SHOULD NOT BE PUT IN A DAILY DRIVER? IS THIS TRUE? THX FOR ALL THE INPUT SO FAR.
08-26-2006, 01:55 PM
#12
5th Gear Member
Join Date: Mar 2006
Location: Nor Cal
Posts: 2,179
RE: WHICH GEAR TO PUT IN MY 05 GT? 3.73 OR 3.90 OR 4.10
ORIGINAL: RICVA05
. As far as 3:90 gears I don't think Ford racing makes them for our car. If you buy any thing but Ford racing gears you could be asking for a lot of noise issues.
. As far as 3:90 gears I don't think Ford racing makes them for our car. If you buy any thing but Ford racing gears you could be asking for a lot of noise issues.
So the 3.90 is a very viable option.
Richard
08-26-2006, 02:01 PM
#13
RE: WHICH GEAR TO PUT IN MY 05 GT? 3.73 OR 3.90 OR 4.10
ORIGINAL: wmtheflash
I'm seriously considering this modification. I have an 06 auto GT with the stock 3.31. Anyway, I plan on installing both the gears and an aluminum driveshaft at the same time.
I'm considering 3.55's or 3.73's. I can't decided!
My good friend at work tells me that the 3.55's will hardly make any difference at all (about 7% higher RPM's at a given speed vs. 12% higher RPM's for the 3.73's).
I'm leaning towards the 3.55's, less wear and tear on the engine and better gas mileage. I'm also hopping that the alumnium drive shaft makes up for the difference between the 3.55 gears and 3.73 gears. Any thoughts?
By the way, here is a handy calculator that computes engine RPM for various gears / tire sizes.
http://tech.oldsgmail.com/axle_RPM.php
I'm seriously considering this modification. I have an 06 auto GT with the stock 3.31. Anyway, I plan on installing both the gears and an aluminum driveshaft at the same time.
I'm considering 3.55's or 3.73's. I can't decided!
My good friend at work tells me that the 3.55's will hardly make any difference at all (about 7% higher RPM's at a given speed vs. 12% higher RPM's for the 3.73's).
I'm leaning towards the 3.55's, less wear and tear on the engine and better gas mileage. I'm also hopping that the alumnium drive shaft makes up for the difference between the 3.55 gears and 3.73 gears. Any thoughts?
By the way, here is a handy calculator that computes engine RPM for various gears / tire sizes.
http://tech.oldsgmail.com/axle_RPM.php
08-26-2006, 03:04 PM
#15
3rd Gear Member
Join Date: May 2006
Location:
Posts: 700
RE: WHICH GEAR TO PUT IN MY 05 GT? 3.73 OR 3.90 OR 4.10
Someone let me know if my math is incorrect, I used stock Perelli's, .67 transmission ratio and changed the rear end ratio to compute the numbers. I only did it in 5th gear to save time!
08-26-2006, 03:15 PM
#16
RE: WHICH GEAR TO PUT IN MY 05 GT? 3.73 OR 3.90 OR 4.10
ORIGINAL: wmtheflash
Here are some graphs I did...just saw the post on top speed. I'll get the computer to run the data in a minute and post it. Someone let me know if my math is incorrect, I used stock Perelli's, .67 transmission ratio and changed the rear end ratio to compute the numbers. I only did it in 5th gear to save time!
Here are some graphs I did...just saw the post on top speed. I'll get the computer to run the data in a minute and post it. Someone let me know if my math is incorrect, I used stock Perelli's, .67 transmission ratio and changed the rear end ratio to compute the numbers. I only did it in 5th gear to save time!
08-26-2006, 03:16 PM
#17
RE: WHICH GEAR TO PUT IN MY 05 GT? 3.73 OR 3.90 OR 4.10
ORIGINAL: Kaldar142
whats our top speed with 4.10s, 4.30s and 3.90s?
whats our top speed with 4.10s, 4.30s and 3.90s?
actual, i know sleeper hit 175ish with 4.30s casue it makes 5th gear useable to overcome the drag, however that was the total top speed, with 4.10s you could hit 190 mph if you have the HP to overcome the drag but mostlikely dont, so 160ish maybe
08-26-2006, 03:21 PM
#18
3rd Gear Member
Join Date: May 2006
Location:
Posts: 700
RE: WHICH GEAR TO PUT IN MY 05 GT? 3.73 OR 3.90 OR 4.10
Whoops, sorry about putting down the wrong ratio...should be virtually no difference between 0.68 and 0.67, though. The difference between the stock engine RPM and new engine RPM will stay the same.
Ok, the last one is 4.10 vs. 3.55 taken out a long way. I don't know how valid the model is at these speeds, though, tires, wind and other factors are going to really complicate things and the graph just isn't going to be right. Still, I guess it's a starting point for discussion. I know it really over predicts the top speed. I don't think it would be hard to do the real numbers if you had all the data...I just don't feel like spending too much time on it.
I think I'll go drive the car some.
Ok, the last one is 4.10 vs. 3.55 taken out a long way. I don't know how valid the model is at these speeds, though, tires, wind and other factors are going to really complicate things and the graph just isn't going to be right. Still, I guess it's a starting point for discussion. I know it really over predicts the top speed. I don't think it would be hard to do the real numbers if you had all the data...I just don't feel like spending too much time on it.
I think I'll go drive the car some.
08-26-2006, 04:35 PM
#20
4th Gear Member
Join Date: May 2005
Location:
Posts: 1,123
RE: WHICH GEAR TO PUT IN MY 05 GT? 3.73 OR 3.90 OR 4.10
ORIGINAL: mustangman02232
actual top speed or theroretical top speed?
actual, i know sleeper hit 175ish with 4.30s casue it makes 5th gear useable to overcome the drag, however that was the total top speed, with 4.10s you could hit 190 mph if you have the HP to overcome the drag but mostlikely dont, so 160ish maybe
ORIGINAL: Kaldar142
whats our top speed with 4.10s, 4.30s and 3.90s?
whats our top speed with 4.10s, 4.30s and 3.90s?
actual, i know sleeper hit 175ish with 4.30s casue it makes 5th gear useable to overcome the drag, however that was the total top speed, with 4.10s you could hit 190 mph if you have the HP to overcome the drag but mostlikely dont, so 160ish maybe