[Kerplunk]

I used to own an 1994 325i before getting this m3.

While driving at the same speed say 60mph i get rpms of 2.5-3.5 in my 3.25i

However in the m3 i get 3.5-4.5 (this is in fourth gear) I think in 5th it goes around 3.5-4...but i have to make sure.

I was always told to keep your car at 3.5 rpms for daily driving.

Note: I am not accelerating.


Is this normal ? I'm trying to learn around parental car folk lore.

thanks

mike

[95RogueM3]

you have a different rear differential in the m3 than you did in the 325 and that is what is causing your rpms to be higher.

I dont know what year m3 you have and whether or not you have an auto. If you have a 95 manual you have a 3.15 rear diff. If you have a 96+ manual you have a 3.23 rear diff. If you have a 96+ auto you have a 3.38 rear diff. The higher the numbers go the better acceleration you will get but you will sacrifice top speed. The higher diif ratio will cause each gear to end earlier and will raise rpms at any speed across the board.

I am not sure what kind of gearing a stock 325 uses, i would be purely guessing to say a 2.93.

I dont know about always driving at 3500 rpms, i would say stay lower than that when possible for extended periods of time..might as well save gas and be able to hear yourself think. Theres no problem exceeding 3500 i just wouldnt cruise there all of the time.

-Richard

[97BLKM3COUPE]

Completely Normal in this car. Notice how you don't have to downshift from 5th on the highway to pass. Just give it gas and go.

[Sammyzuko]

I did some highway driving this past weekend and I was a little surprised at how high the rpms were. At 80mph I was at 3500 rpm. This seems excessive, especially when I'm doing it for a 45 minute drive. My gas mileage appears to be excellent though and I've done my share of quick starts.

[indicaM3]

i go home once or twice a semester (two and a half hours) and cruise between 80-90 mph the whole way. 96 5 spd satys between 3.5 and 4k rpm.

[Kerplunk]

hmmmm i guess i'm in the norm then.

I have a 96 Manual. The car is new to me. So i'm still going over it. Thought that was a bit high.

Thanks for the replies, made me feel a bit better about the high rpms.

[astan100]

Those high revs often make me (and others) wish for a 6sp in our cars. I like that the mileage isn't bad for revving so high though. If I'm not varying speed much, I've gotten up to 29mpg on the highway going a constant 75-80.

With a 6 sp it woudl be even better. There were people who did an analysis and the 6 sp won't save you enough in gas money to pay for itself, so stop thinking about that right now.



The 6 sp is a good way to go if you're thinking about doing a diff swap also though. You won't lose much practicality, but your wallet will be a lot lighter.

[JB///M3]

Normal...