What gears?

[89' RICE COOKER]

Im wondering what gears in the rear came stock on a 89' 2.3 auto?
3.55? im looking to upgrade them this weekend and wanted something a litter better, but not too extreme because I still do alot of freeway driving being its my daily driver. what would be a good upgrade...3.73? are 4.10 gonna be too harsh on the freeway and gas?

 

[ethangsmith]

Rear gears should be 3.73 for your automatic. My 88 auto has them. 4.10s may be a bit much, but it depends how much you're worried about fuel economy.

 

[89' RICE COOKER]

3.73s really? theres no ratio i can get between those and the 4.10s is there? with the 4.10s im not really worried so much about gas as i am about the RPMs on the freeway. its a new motor with about 8k. how much is it gonna change, say around 75mph you think?

 

[ethangsmith]

There is a way to calculate it out, but I have no idea how to do it. What I do know is that my 88 automatic pulls about 2000rpms at 55mph in overdrive with the converter clutch locked. Since the speeds around here are slow and it's a fairly built-up area, I've probably only ever done 75 in the car once or twice. I would imagine it would be at about 2500-3000rpms. Putting 4.10s in would make it quite a bit higher. Probably at 55 you would see rpms of 2500-2750 and at 75 you would be over 3000, probably near 3500-3750. I see you've done exhaust and intake work. That should have woken it up a little bit. Do you have a Ranger steel header on it? That gives you a little more low-end grunt.

 

[351wcoupe]

Got to merkurtech.com and you'll find some cool little calculators. you punch in your trans info, tire size and rear gear and it will tell you "X" mph and at "X" rpm in each gear.

 

[89' RICE COOKER]

sweet, thanx. ive been there a long time ago. just couldnt remember where i saw it.

 

[bhuff30]

Since the speeds around here are slow and it's a fairly built-up area, I've probably only ever done 75 in the car once or twice. I would imagine it would be at about 2500-3000rpms.

4.10's isn't such a big jump actaully. It is only ~10% difference. So what was 3000 at 75, would be 3300 at 75. What was 2000 at 55 would be 2200.


In my opinion, it wouldn't be worth it.

As for not going 75, that's a bit surprising to me. Barely a day goes by that I'm not in a 70mph zone.

My 88 has 3.73's and no OD. It is a bit much on the highway. Both my cars have no trouble hitting 75mph in 9s or less though

 

[tjm73]

3.73s really? theres no ratio i can get between those and the 4.10s is there? with the 4.10s im not really worried so much about gas as i am about the RPMs on the freeway. its a new motor with about 8k. how much is it gonna change, say around 75mph you think?

If you had an 8.8" you could get 3.91's but with the 7.5" you go from 3.73 to 4.10's.

 

[Slow92LX]

Auto 4 banger mustangs came with 3.73s in your 7.5 rear. this thread has some good info -> http://forums.stangnet.com/showthread.php?t=629160

 

[89' RICE COOKER]

4.10's isn't such a big jump actaully. It is only ~10% difference. So what was 3000 at 75, would be 3300 at 75. What was 2000 at 55 would be 2200.


In my opinion, it wouldn't be worth it.

As for not going 75, that's a bit surprising to me. Barely a day goes by that I'm not in a 70mph zone.

My 88 has 3.73's and no OD. It is a bit much on the highway. Both my cars have no trouble hitting 75mph in 9s or less though

Bhuff, what do you mean " not worth it"? like money and time wise or just gas and freeway wise?
p.s. was the header i asked you about on ebay from a '95? is it the 93-95 that i should pull, or are there more years? sorry to go off subject.