changing differential help needed
Thread Starter
Intermediate
Joined: May 2019
Posts: 42
Likes: 9
changing differential help needed
I have a 97 automatic coupe that has the stock 2.72 differential. My car is just a bit over 300hp at the wheels and may wind up at closer to 400hp in the future. I really want to change the differential to 3.42 for better takeoff, but I'd like feedback from people who have done it. I drive this car a lot on the street, so it's not a track car. Can anyone answer the following questions?
difference between 1 and 3 rib differential as they relate to my car?
Would I have to change the stock axles?
what do you have to change in the tune with this change?
Can it be changed with say an HP tuner without messing up my current pro tune?
Thanks for any tips you can give me. I've tried reading and searching here, but just didn't find clear answers.
difference between 1 and 3 rib differential as they relate to my car?
Would I have to change the stock axles?
what do you have to change in the tune with this change?
Can it be changed with say an HP tuner without messing up my current pro tune?
Thanks for any tips you can give me. I've tried reading and searching here, but just didn't find clear answers.
Last edited by RSRelic; Oct 2, 2020 at 10:37 PM.
Safety Car
Joined: Mar 2005
Posts: 3,742
Likes: 1,205
From: Wisconsin
The difference between 1 rib and 3 is strength. The 3 is stronger. No the stock axles are fine. Shift points for one, can't remember what else. HP tuners would handle it without messing up the tune.
Advanced
Joined: Mar 2019
Posts: 76
Likes: 19
From: Rochester, NY
I just did this on my 98. feeder82 is right on, the 3 rib is stronger, stock axles are fine. I sent my computer off for a mail order tune, so I dont know the details on that, but HP tuners will get the job done provided you know what you are doing. Mine is still not quite right, but good enough until I get a full tune later.
I spent $2400 in parts and did everything myself except the tune. About 11-12 hours by myself. I'd say it's worth it if you plan to keep the car. Lots of fun on the street
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I spent $2400 in parts and did everything myself except the tune. About 11-12 hours by myself. I'd say it's worth it if you plan to keep the car. Lots of fun on the street
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Race Director
Joined: Oct 2004
Posts: 12,859
Likes: 4,658
I had a 3.15 diff, and went to a 3.42, and I could see quite a difference. Going from a 2.73 would be even more noticeable. I don't know what your future plans will be for the car, but while your diving into it this far, you may want to look into getting the hardened output shaft inside the diff itself. It is a known weak point at a certain amount of power/sticky tire figure, though what that point is I'm not sure. I did it to my 2000 because it was a lot cheaper to do while swapping out the assembly. Good luck with your project.....
Last edited by grinder11; Oct 5, 2020 at 09:41 AM. Reason: Spelling
Melting Slicks
Joined: Mar 2018
Posts: 2,502
Likes: 187
From: California
No need for all these harder shafts ect...unless your planning on 1000+ ponies .......the only tuning other then your trans setting to a 3.42 will be the throttle and trans tuning meaning when amd how much throttle position u want it at before a kick down to a certain gear ....yada yada automatic tuning may be much harder then tuning a manual car as we don’t have rpm idle bases in gear or out of gear there’s just a bit more to do on your file so suggestions is start digging through the tune section....
