jherrera1341

Please excuse my ignorance on this matter, this is only my 2nd time using a posting. I hope this gets out there in the right section.
I need a bit of help infiguring out the higher than normal RPMS on my 91 RS 5 speed manual. I am getting 3000 RPMs at 70 mph with a 3.08 gear ratio. Is this normal/correct?.
It just seems awfully high in comparison to other stock camaros. The clutch is not slipping at all. I have verified the gears in the rear end. I don't know what, if anything, is causing this. I have checked calculators and all tell me that I should be running about 2200 rpms at 70pmh with a 3.08 gear ratio. I don't know if the previous owners did any mods to the transmission. It doesn't look like it.
Is there a gear ratio that can be changed in the transmission itself?
Any guidence would be greatly appreciated.

sofakingdom

iTrader: (1)

No; not correct.

Most likely your tach is off. The stock ones in these cars virtually always fail by reading high, WAY high in many cases. I'd say in yours, where it's only about 50% high, is pretty good... I have one that reads over twice what it should, and others on this board have had them read more than 3 times reality.

Go check it against actual test equipment and I'm sure you'll see you don't have a problem with RPM, you have a problem with your "tach".

jherrera1341

THanks for the tip.
I checked it with a portable test equipment and was getting between 50-150 rpms less on the portable test equipment. I am going to get another test equipment tomorrow and retest it just to see if its consistant.
It sure doesn't seem like its off a whole lot.
Do you know if there is a chip that would make the rpms run higher?
I looked under the dash and saw that the ecm has been rebuilt. I don't know if it has been modified of just repaired.