RPMs

[D. Avino]

I just purchased a 95 MTX. I love the car. This is just a general question. I was wondering what other SHO owners tach out at around 70 mph in 5th. My car is at about 2800 rpm, is that normal. someone told me that that seemed really high, that it should be more like 2200 rpm. Is this the case? also note that the car has 225 r60 tires instead of 215 r60's so that kinda messes up my speedometer. however, that would make the tach be lower at higher speeds, so i don't really know. Anyone have any insight?

Thanks
Dave

 

[Rob94]

My 94 MTX tachs out at about the same at 70 in 5th. The tires you mentioned are a hair WIDER than original. Wider should in no way affect your speedometer.

 

[twr]

Actually the wider tire makes a difference. Remember that 60 is the aspect ratio - that is 60% of the width. If your speedo is reading 70mph your actually going 71.26 - not that much of a difference.

 

[smcallis]

2800 rpm at 70 is pretty good. I had a supra that did like 3400 rpm at 70. I hated that car.

 

[sdpatt]

The speedometer only knows how fast the transmission output shaft is spinning. It has no idea of the true ground speed. A difference in tire size (yes, those 225/60-16s are tall) will change the ground speed for a given engine rpm. Other factors such as tread depth or even inflation pressure will also affect the car's true velocity at a given engine rpm.

All manual transaxle SHOs are geared the same. There are, however, accuracy differences in the tachometers. Mine reads a little high, but also shows about 2,800 rpm at 70 mph. This can change a little depending on the temperature of the DIS module where the tach signal is tapped from.

<small>[ September 18, 2002, 02:44 PM: Message edited by: sdpatt ]</small>

 

[D. Avino]

Hey guys. Thanks for the info. it is reasuring to know that the car is fine. gotta get some new tires for it anyways, it has garbage on it right now, they're all pretty much bald, i wonder why...

 

[Slo-Sho]

Go with 225/55/16 tires. You can't really get a performance tire in a 60 series.

 

[Ishodu]

I got me a 95mtx and at 110kph or 70mph my tach is at about 3. Maybe that has something to do with the buzzing comming out of the speedo?

 

[shojuan]

My 89 MTX shows 2600 at 70 mph

Rick