A question about speed reading at 5th gear

[gorgeousgeorge]

Hi.
I would like to thank everyone who responded to this thread. I inspected the ratio of my rear end today and found the propeller shaft rotate 3 and about a half turn while rear tire making complete 1 turn. I believe the final ratio is 3.45, i.e. stock.



I did the inspection at my friend mechanic?s shop. My friend mechanic was under my ZR-1 and was counting the number of rotation.

I concluded that the tachometer is inaccurate.

DOES THIS OFTEN HAPPEN TO C4s?

How could I do to fix this problem?





When the GPS meter read 223.9km/h(=140MPH), my inaccurate tachometer read 7000 rpm. The true rpm will be around 5200 to 5400 rpm, if the true speed of 7000 rpm in 5th gear is around 180MPH to 200MPH.

I am wondering what to do next


By the way, I talked with my friend mechanic about how we should improve our Corvettes till 10 oclock at night

Yoshi Honda
1991 ZR-1

[Aurora40]

Originally Posted by gorgeousgeorge

DOES THIS OFTEN HAPPEN TO C4s?

It's not uncommon, though yours is off by a huge amount. You can either buy a new instrument panel that hopefully is more accurate, or you will have to have yours fixed/repaired.

I don't know who repairs them, but people have had it done.

In the meantime, you can run the revs up a lot higher and really get to enjoy some of that acceleration the LT5 provides. The higher revs are where it's the most fun.

[gorgeousgeorge]

Originally Posted by Aurora40

In the meantime, you can run the revs up a lot higher and really get to enjoy some of that acceleration the LT5 provides. The higher revs are where it's the most fun.

Bob,
Now I understand what you mean. I ran my LT5 up to over 8000 rpm (which is to be around 6300 rpm or a little higher if the tachometer is accurate) yesterday. LT5 really roared like a beast! I have been missing the last 1000 rpm which makes ZR-1 most fun due to the inaccurate tachometer. I have to look for an accurate tachometer..

Yoshi Honda
1991 ZR-1