3.64 diff

[mysticzhp]

Hey guys, so I'm picking up a diff from a auto zhp. I believe it's 3.64 ratio. I will be installing it on my 04 6spd. What can I expect with such a short ratio? I'm not concerned with gas millege, has anyone done this that can input? Will it be a straight up swap? Do I need to change any flanges? Thanks guys.

[az3579]

Hey guys, so I'm picking up a diff from a auto zhp. I believe it's 3.64 ratio. I will be installing it on my 04 6spd. What can I expect with such a short ratio? I'm not concerned with gas millege, has anyone done this that can input? Will it be a straight up swap? Do I need to change any flanges? Thanks guys.

Drive whatever speed you want to determine revs for, then shift into 5th. This is more or less what revs you'll be doing with the 3.64 in 6th gear.
It should be a direct swap.

[wertyu78]

The 3.64 FD suits our cars very well. I love it. I've tried a 3.15, 3.38, 3.46 and 3.64 - currently, I have a 3.64 in the car and have no plans to switch. Coming from an auto ZHP, it should have a finned cover which is pretty cool (pun intended).

My average MPG on the highway went from 32.5 with a 3.07, to 28. Not a bad loss considering the usefulness of the shorter gearing. On an autox course, you'll find you can keep it in 2nd for most of the course, and easily grab third on the higher speed stuff. For road course driving, you'll be in 3rd and 4th most of the time, grabbing 5th in the straights (like back of Road Atlanta).

My only suggestion would be to send it off to Diffsonline and have it built into a LSD. Sure, its a bit costly..... but it's so friggin worth it.....

[ELCID86]

The 3.64 FD suits our cars very well. I love it. I've tried a 3.15, 3.38, 3.46 and 3.64 - currently, I have a 3.64 in the car and have no plans to switch. Coming from an auto ZHP, it should have a finned cover which is pretty cool (pun intended).

My average MPG on the highway went from 32.5 with a 3.07, to 28. Not a bad loss considering the usefulness of the shorter gearing. On an autox course, you'll find you can keep it in 2nd for most of the course, and easily grab third on the higher speed stuff. For road course driving, you'll be in 3rd and 4th most of the time, grabbing 5th in the straights (like back of Road Atlanta).

My only suggestion would be to send it off to Diffsonline and have it built into a LSD. Sure, its a bit costly..... but it's so friggin worth it.....

You didn't like the 3.46?


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[wertyu78]

It's a good FD, but not "aggressive" enough for me. Definitely more highway friendly. I average 29/30mpg with it.


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[ELCID86]

That's what I'd be leaning towards for my mostly interstate commute.


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[NoVAphotog]

That's what I'd be leaning towards for my mostly interstate commute.


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+1

We'll definitely do some good testing of the 3.46 lsd later this summer Shawn.

Sent from an HTC One

[ELCID86]

+1

We'll definitely do some good testing of the 3.46 lsd later this summer Shawn.

Sent from an HTC One

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[jakksfor20]

For interstate driving we have found ourselves wanting a little bit lower rpm's with ours. My 323ci with the 5 spd doesn't bother us, but the sustained 3400rpm's on the ZHP at 80mph just seems harsh. I told the wife that I will look for a 3.46 and send off for LSD to put in later this year. Plus, 1st gear is basically unusable for regular commute.


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[mysticzhp]

Thanks for all the input guys. I still haven't gotten my diff as the seller seems to have no time to meet up. I hope he's not pulling my leg cause I'm really interested in this diff and been talking to this guy for over a week trying to make a deal happen. He's parting out a zhp from which I'm trying to get the diff from if he doesn't come trough I'll have to source one from a z4.