a92whitelude

My rpm is 3000 at 60, not sure if tach is right sounds kinda high. I have 205-40-17s so I know they are a little shorter than stock.

G_Loc

That's normal

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pprowler6

what gear?? 5th i take it

a92whitelude

Ya in 5th, if thats normal it must not have much of an overdrive. .85 or so.
thanks.

lude-atic

High 4000 at about 60 to 70 mph. Thought that was kinda high

red92si

4000rpm should be ~80mph in 5th.

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Tyler

WHITE96SI

I'm at 28-2900rpm at 60mph with 205/55/16. It makes my speedo read dead nuts correct.

G_Loc

Your tire size won't have an effect on the speedometer reading, only on your actual speed. Throw on any size tire / rim combo, it will always read 60mph @ 3k

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a92whitelude

Hmm does'nt it get speedo reading from trans rpm.I see you meen indicated speed --not actual speed.

WHITE96SI

Hmmmmm that's funny with my stock 205/55/15 I was reading about 3100rpm at 60mph and the speed detectors on the side of the highway read 63mph. Now I am at 28-2900rpm at 60 and the radar sign states 60mph. who cares if any tire will say 60mph if it's not correct? That's all I'm getting at. If it reads 60mph I want to be going 60mph so when the CHP is behind me I know what speed I am really going...

G_Loc

Are you running a stock H23 manual transmission? Regardless, like I said, the speedometer will always read the same speed for a given RPM. As a92whitelude noted, the VSS is mounted on the transmission. Maybe your speedometer and tach readings have gone off slightly or you're just seeing things

Just for reference, a tire size / effect on speedometer calculator: Tire size calculator

Your current setup reads 4.2% slower than stock
When the speedometer reads 60, you're actually going 62.5mph

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NICOLEWALPOLE

I have about the same problem, I have a stock 92 SI but mine is an automatic transmisson H23A. I have had my car since 1996 & never had the Rpms run this high, at 80 mphs my RPMs are 3600. Use to run around 2900 RPMs at 80Mph. Now at speeds of 45 the RPMs run around 2500. Seems like it is not locking into overdrive. I have rebuilt the transmisson & put a new torque convertor on still had the problem so I bought a Japanse transmisson but still have the same issue. What else could cause this problem?