3.15 to 3.46 diff initial impressions

Gregster

Gregster

Legacy Member
I made the switch tonight. Here are some initial thoughts

Normal driving around town I didn't notice a difference at all, I mean zero. Most people on the internet seemed to be moaning about 1st being too short. Under brisk acceleration I felt that fall back into the power band and was quicker on it's feet. I wouldn't say it's "faster" but it sure has more pep to it and it's more fun to drive. On the highway the difference in revs is noticeable but in 5th the car goes when you get on the gas which I love, it feels fantastic! She pulls very nice compared to the 3.15 which I always felt was sluggish when passing people.

Not sure about gas mileage yet...

I paid 150$ for the diff, 60$ for new seals and 12$ for Motul gear oil. Install took me 1.5 hours. Well worth it!
 
I went the other way, I went from 3:46 to 2:73....:)

I wanted a 3:07 but 2:93 is all I could find.

Ironically I have found a 3:07 but do do the work to go 2:73 to 3:07 is a serious waste of time.

If I had a 330 the extra tall gear may be fun but I have a 325 and it will never be quick, but having to shift half way across an intersection got annoying, and the lower revs on the highway is nice.

Now a 3:64 and a 6 speed (which is what I think the M's have) would be great!
 
Gregster, when cruising at 118kmh, where are your revs?

I have the 3.15 for now, and will be swapping the 3.46 within a week or two. I have done the calculations but want a real life confirmation.

cheers.
 
Too bad the gearing isn't comparable between the E46 and the F
With a 3.07, I was roughly at 3,020rpm at 118.
With a 3.15, I'm roughly at 3,110rpm at 118.

Now just need slap in the 3.46 and give her a go.

Still very very tempting to just rip that stuff out and dump a 350z 6 speed and a 4.11 R200 VLSD and be done with it. At that point, a RB25 is steps away
 
Installed the 3.46 last night from the 3.15. The acceleration difference is amazing. Really wakes the car up. Yes it's a bit revvy on the highway at 3450 at 118 but that's the down side. I'm sure once i floor it to pass, it will actually accelerate now.

Really worth while swap to do. Can't wait to be mean to her and see what my 0-60 time is on the on ramp.
 
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