Engine RPM

[528iTdude]

Hey everyone!

I am wondering if my engine RPM is normal? At 60 MPH, my tach says about 2200 RPM. I thought that it should be around 1900 or so. What's yours say? My car is a '99 528 iT wagon, 6 cyl. auto. Thanks!

[fastshivy]

Mine is a 540i, so it will be different...Here is a formula you can use to calculate it. You will have to plug in your car specifics, look in the hand book or call the dealer, google etc. You will need the overdrive ratio of your tranny...rear end ratio and tire size for your specific vehicle. Maybe someone on this forum knows these or a link to get there.

RPM= MPH X Gear X final drive x 88/tire circumference

so in your case
MPH = 60
overdrive gear=? Somewhere around .75
rear end ratio= ? Somewhere around 3.0
tire circumference can be found by using this link
Tire Dimensions Made Simple - Discount Tire Co.

so you can see there are alot of variables

Have fun Proffessor!

[528iTdude]

Well, I must say that this is a very informed post!!!! I am just looking for some feedback from other 528 iT owners as to what their cars RPM's are at 60MPH!!! One thing that you made me think about is that I do have 16" wheels on my car, so I wonder if this should lower or make the car's RPM range higher? Just a thought. What's your take on the issue? Let me know, and thanks for your reply! JM>

[fastshivy]

Tire size always affects the rpms....that is why you can not compare what other vehicles are doing, unless they are an exact match for everything in the equation. You could have a 16" or 18" wheel with the exact same outer dimension depending on the profile width etc.

I had 20" on my Tahoe and went to 18" with a taller tire to get the same rpm at a set speed. Hated the 20's (Cast Alum) and love the 18's (Forged) much nicer ride and handle the same.

[cnn]

Originally Posted by 528iTdude

Well, I must say that this is a very informed post!!!! I am just looking for some feedback from other 528 iT owners as to what their cars RPM's are at 60MPH!!! One thing that you made me think about is that I do have 16" wheels on my car, so I wonder if this should lower or make the car's RPM range higher? Just a thought. What's your take on the issue? Let me know, and thanks for your reply! JM>

At 60mph, my rpm is 2200 rpm.
Normal!

cnn
98 528i 5spd stock wheels.

[MEDSTUDENT87]

I have a 90' 525 and my rpm gauge reads 2200 rpms at 60 too but my car is an auto!

[528iTdude]

Looks like I am on the right side of the tracks! My car is also an automatic, therefore it looks like my RPM number of 2200 is appropriate. Any other feedback would also be greatly appreciated! Thanks for your responses. JM>
:lol: