gears and such

hepcat

Registered User
Well first thing is gears for my 89 XR7 with the stock AOD rebuilt with a lentech valve body. I don't know if I want 3:55 or 3:73
Engine power is a little over stock I would beleave. but the main thing is where highway rpms are when at 66 with both gears.
also how is first gear with the gears?

any thoughs appriciated.

Thanks
 
I've got the 3.73's and love them.

Going from 3.08 to 3.73 is a 20% difference. So, instead of 2,500rpm @ 75pmh, you turn 3,000rpm. Highway mpg drops from 27 to 22.

Lee
 
Re: I've got the 3.73's and love them.

rivlee said:
Going from 3.08 to 3.73 is a 20% difference. So, instead of 2,500rpm @ 75pmh, you turn 3,000rpm. Highway mpg drops from 27 to 22.

Lee

I have a 90 SC and currently have and AOD w\TransGO shift kit and the factory 3.27 gears (I checked the axle code). I'm planning on upgrading to the 3.73's when I rebuild my trak-lok unit. I may just do the cobra pumpkin swap and do it all in one shot. I'm not really concerned about highway, but what do you think I should expect RPM and MPG wise?
 
I heard a lot of good and bad things about AODs running on 3.73s.

If you're doing a lot of routine highway driving, I wouldn't recommend it. You'll lose at least 100 miles to a tank. With today's gas prices, I'd stick with stock gears, or something a higher, like 3.27s or 3.31s.

On the flipside, if you go with the 3.73s, you'll have a tendency to burn the tires off the line, if you're heavy on the pedal. Mechanically, your car will run like it virtually lost 500 pounds or more.

The choice is yours, on what you wanna do. Good luck!
 
MN12 KID,
I already have the 3.27's that came stock(axle code on driver's side door jam checks out as 3.27) so 3.31's would almost be a "why bother". My car wasn't optioned down to the 3.08's. I've seen so many posts with numbers all over the place and I was just wondering what some real world numbers might be. Some say less than 1 MPG difference. Others say big impact. As long as I don't get down to the 3.3 MPG my friend's Nova is getting, I don't think I'll complain too much. Then again, if I had the kind of power he's running I don't think I'd complain anyway. Last time I talked to him he was still running 550 - 600 HP at the rear wheels.
A majority of my driving is non-highway. The other thing I'll have to figure out at some point is the age old question, "HOW MUCH??", but I'll worry about that later. For now I'm just saving up and taking care of routine maintenance. After trans and motor mounts next week, "Baby needs a new pair of shoes". It's once again tire time. Thanks for the advice.
 
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gears

Well right now I have 3:08 and run arround 2100 at 75. So I think I will go with the 3:55. I love my lenteck because the gears scratch pretty good now and can't wait for gears.

Well thanks for the help.
 
MN12 KID,
MN12 KID said:
Actually, I was replying to HEPCAT. Our posts were active at the same time.

Ooops. My bad! Didn't mean to butt in. Sometimes it gets a little confusing about who's talking to whom.:eek:
 
Running 3.73's right now. Last road trip I took it was 22.5 going and 22 coming back. Street driving I average 16-18. Not too bad in MHO for a 13 year old car. And I definitely feel the power more at the line. I can't exactly remember what 65 is at right now... would say about 2250-2500 rpms.

esco
 
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