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ThatWhiteCivic
11-04-2009, 02:24 PM
Ok I was told there are 4:11 gears in my 8.8 and I feel like it's too much gear. Especially when cruising on the freeway, somewhere around 3000 rpm at 60 mph. Going down to a 3:73 or 3:55 what would my rpm be at 60 mph
Irish
11-04-2009, 02:27 PM
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WhatsADSM
11-04-2009, 02:41 PM
It is simple linear math based on the known rpm/gear you have now.

3.73s:
3.73/4.11 * 3000 = ~2722 rpm at 60

3.55s:
3.55/4.11 * 3000 = ~2591 rpm at 60
ThatWhiteCivic
11-04-2009, 02:52 PM
Awesome thanks guys probably going with 3:55's in the spring. I want to take this car on longer drives when it gets nice out again.
Irish
11-04-2009, 03:21 PM
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-stew-
11-04-2009, 09:48 PM
I love my 3.73's. Difference between 3.73 and 3.55s is only 200 rpms.
xxtremeteam
11-04-2009, 10:18 PM
hmmm and with my aod I want 4.10s but maybe 3.73s would be ok
TransAm12sec
11-04-2009, 10:35 PM
http://www.wallaceracing.com/calcrgr.php
WhatsADSM
11-05-2009, 09:23 AM
http://www.wallaceracing.com/calcrgr.php

That calculator is a little suspect. There is no input for ratio of the last gear in the trans... so it must be assuming something (likely 1:1 ratio). That is probably okay for a race car, but with any trans with overdrive it's not going to be right.
TransAm12sec
11-05-2009, 09:51 AM
You use the gear that is closest to a 1:1 ratio, similar to a dyno run.

Either way, it's based off this equation.

(MPH x Transmission Gear x Rear Gear x 336) / Tire Diameter(inches) = RPM
Sprayaway Fox
11-05-2009, 07:01 PM
Those look like a 28 tire on your car in the sig. I would do a 3.73 theres a reason that they sell so many, plus you would have stoplight capabilities and hwy miles.

I had a 347 E cammed 5 speed car with 4.10 and a 26'' and I got 22 MPG's. Looking back 3.73's is what everybody told me and I should of did.

GL though whatever ya choose.
Reverend Cooper
11-05-2009, 10:01 PM
tire size and trans ratio make a huge difference also.for instance on my 18's with the trans i have and 4.10's it is at 3000rpms at 84 mph
70 cutlass 442
11-07-2009, 05:30 PM
What trans do you have? my 95 with a 28" tall tire and 3.73's were perfact for the freeway, but I had a T5 wich was a .68 5th gear. But since you have a 4 eyed, you could have any trans in that year range which would be either a .68 .63 or .80 ratio.... I dont know what the autos had for a high gear, but im guessing you have a t5. I cant remember what my rpm was, but I know i averaged 20 MPG on the freeway and it wasn't winding up high at all.
ThatWhiteCivic
11-08-2009, 11:55 AM
yeah it's a 28" tire with a C4 trans
badass88gt
11-08-2009, 12:17 PM
Thats your problem, you have no overdrive. Better get used to it, swapping to a 3.55 with that tall tire is gonna make the car feel like a turd.
70 cutlass 442
11-08-2009, 05:52 PM
Thats your problem, you have no overdrive. Better get used to it, swapping to a 3.55 with that tall tire is gonna make the car feel like a turd.

QFT, What stall do you have? that will make a big differance, but if you goto a 355 I will tell you right now you will be disapointed.
1320PNY
11-08-2009, 06:20 PM
Here is one I downloaded and then modified for my car. I have a 5-spd 2006 with 3.73 gears. I have 27" tires (255/45/R18). If it works for you with little modification great. If not, PM me and I will work out the details and send it to you.
ThatWhiteCivic
11-08-2009, 07:26 PM
I have a 9.5" converter 3000 stall
badass88gt
11-08-2009, 09:28 PM
Like I said, it will be a pooch. You have to decide whats important to you, going quick from a stop or nice highway cruising. You are not going to get both with your current setup.
70 cutlass 442
11-09-2009, 01:59 AM
I have a 9.5" converter 3000 stall

yeah, horrible combo if you want to be fast on 3.55s.... you will hate it... only thing 355s are good for are turbo cars and fuel economy.
Stangman98
11-09-2009, 06:44 PM
What kind of gear is it?