Thinking about losing the 4.10s and going w/ 4.30s

helty said:

Ive got quite a bit of gear whine and Ive been meaning to upgrade to some 31 spline Mosers and an Eaton/Auburn/Detroit differential and a complete bearing and seal kit for a while now. Im also getting some 15x10" Weld Pro-Stars and MT ET Streets for use at the track. Ive decided to stay N/A and go the head/cam and full bolt-on route with my car. I already have 4.10s, but am seriously considering 4.30s. Ive recently become a track whore so of course I want to get everything out of my car that I can.

1. Our local track is 1000' (i know ) I want to hit the 1/4 sooner or later, will I have to shift into 5th with 4.30s in the 1/4 or will I be right at red-line? Cams are a future upgrade so keep that in mind, but what about as the car sits right now?

2. Ive also given the 3650 a healthy beating at the track, so Im thinking maybe, just maybe* a viper spec T-56 down the road (way down the road). Anyone have that link that tells you rpms given your gear ratio and tranny? Would that 6th gear really help at all compared to 5th in the 3650?

3. Throw in your thoughts on which differential I should go with. Car is a daily driver. Ive heard some positive things about the Detroit, Id like to hear what everyone else thinks.

Give me your thoughts :SNSign:

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helty said:

I could get better gas mileage with my 4.10s than I did with my 3.27s if I kept my foot out of the throttle. Im not overly concerned with gas mileage anyway, I mean c'mon, I drive a V8. Im more concerned with cruising rpms and speed on a long trip. I know it will be higher with the 4.30s, but how much higher is what Im wondering. I need to find that damn link.

I just wanna get my info together and weigh the pros and cons. Better track times, higher cruising rpms......we'll see.

do you know which is recommended for a DD? I know theres the locker, tru-trac, spool Im pretty sure I dont want the spool, I think its the Locker, but its not a quiet piece. I dont mind that as long as it works as a DD and wont hurt the longevity of the rear end components.

Thanks guys!

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jasonh_86 said:

4.56's That's a hell of a gear!

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helty said:

^^thanks man, I understand your choice of 3.73s if you do a lot of highway driving. I dont do much highway driving at all and I dont mind shifting. But do you understand why 4.10s/4.30s are not that big of a deal on a DD if you dont do a lot of highway driving? I swear if (thats a big if )I kept my foot out of the throttle, I'd get better gas mileage than stock gears.

EDIT: after playing with that gear calculator (which I was looking for, thanks man ) I need that Viper Spec T-56. only 2200rpms in 6th gear @ 80mph with 4.30s

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UDTBadkarma said:

Technically, get a grandma...let her drive 100 miles on the highway in 5th gear at 80mph in a GT with 3.27 stock gears.... then put that same grandma, in a GT with 4.10s same conditions...

You will see the car with 3.27s will get better gas mileage. No denying that. 3.73s, 4.10s, 4.30s...they all keep you in higher RPMs in whatever gear your in, over the stock 3.27s. You really CANT get better gas mileage with 4.10s than you can with 3.27s. No way. higher RPMs = more gas burned.

Now...you might be able to get better gas mileage with your 4.10s than say me with my stock gears...but thats just because maybe i have a heavier foot with my 3.27s than you do with your 4.10s. BUT since you say that YOU get better gas milage with your 4.10s than YOu driving ur car with 3.27s...well thats not possible. Unless you became more reserved with your driving style after u got 4.10s all of a sudden.

bototm line, steeper gears will suck down more gas IN COMPARISON to stock gears. Only way to enhance your gas milage would be to go with 2.90 gears...which came on a rare few of 96-98 GT 5spds.

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