seanof30306

iTrader: (4)

I'm looking for F-body T5 gear ratios. Dis a search, but can't find the info.

Are there any differences between the various years? Mine is an '89.

Edit-

Additional searching on the web revealed this:

1352-196 1989 F-body L03 TBI 5.0l V8 WC (1352-000-196?)
1352-195 1989 F-body LB9 5.0L V8 WC

What is the difference between the two?

I also found these ratios:

1st: 2.95 2nd: 1.94 3rd: 1.34 4th 1.00 5th .74

Surely those can't be the only T5 ratios for F-bodies, can they?

sofakingdom

iTrader: (1)

Those are the LB9/L69 ratios.

The low-perf V8 ones (L03/LG4) are the same, except that 5th is .63. Which is why there's such a HUGE drop from 4th to 5th in those. The cars with the grocery-cart motors served as the "sacrificial lambs" to CAFE.

They were the same in both designs of T-5s.

The 6-cyl cars have MUCH wider ratios; 1st is in the high 3s somewhere. I don't know exactly because I have no use whatsoever for 6-cyl stuff and have never had or worked on one (except for one that a junkyard gave me once that I then had to take back and get the right thing).

seanof30306

iTrader: (4)

Thanks for responding.

Actually, I LIKE the .63 overdrive. I've never gotten into 5th at the drag strip, or on even the longest straights at Road Atlanta and Hallett. I have gotten into 5th very occasionally on top-end runs on the road, but it's a close call between 4th and 5th before my speed limiter kicks in. I don't think, however, that the drop between 4th and 5th would be so great as to kill torque multiplication.

The problems with using an overdrive gear for performance are driveshaft overspeed and the incredible stresses placed on the transmission when it's forced to reduce that much torque.

For me, I'd rather gear my car for the performance I want through the first four gears, then use the overdrive for economical road cruising.

KG427KG427

iTrader: (1)

My issue:

Stock 1991 RS 3.1 swapped rear end so it was a 3.08 drum, swapped it so a 1989 3.27gear ratio disc, left my proportional valve, but I have noticed my breaks are most in the front 65% 70% which is fine, my issue is I'm losing way too much gas mileage since I drive 80miles a day. (Also my rear break lines cables seem to knock when I hit bumps, and bad gas mileage, I need to go lower ratio...


Please help can I change my set up I only get 21mpg

New 02 sensor
Spark Plugs cap wires
Air Filter
Tires 19x10 rear corvette rims
Front 18.5 fronts



Why is my gas mileage bad ?



My timing has to be off ?

Or a vacuum leak but I think that is fine...

ksith

wow i wish i got 21 mpg. I feel lucky to get 10 mpg. I think your problem is you're driving an iroc with a over 20 year old engine. You're not going to get much better then what you have unless you lower your gear ratio. Which if I read correctly you have a 3.1 I wouldn't go lower then what you have. Tip take it easy on the gas pedal and stay out of the higher RPM range

KG427KG427

iTrader: (1)

I was milking it and doing 70mph on freeway.

I used to get 26-27 with my old 3.08 drum rear end.

21 sucks lol


I think it's my tires rims 19x10 rears 18.5x fronts

Gonna check my timing.


I have a 1989 Camaro rear end with 3.27 gear ratio posi

Can I change the gears ?? Lower and if so what is the best for fuel economy

ksith

what size engine do you have? If it is the 3.1 I wouldn't go lower then 3.08. And yes you can change ratios but if you do that you will need to change speedo gears as well. That's just to keep your speedo in range. You also might need a different carrier for the ring gear if you go to 3.08. And if you have never done a rear end before I recommend a shop or at least some you trust that knows what they are doing to swap. Check out summit as long as you know if your carrier is series 2 or 3 you can get a different gear set. You probably have a series 3 with a 3.27

KG427KG427

iTrader: (1)

Yes if you can recommend a shop.

I know I have 3.27 ratio my stock was 3.08 I would like to go back to stock unless any1 suggest I should be different for economy purposes. Yes I have a 3.1 V6


My rear end I'm pretty sure is off a 1989 iroc and it's a for sure 3.27 Australian rear???


* so I can change my ratio from 3.27 - 3.08 and should I change barrinings or anything else?