What's the normal engine RPM @65mph while in overdrive?

[syclone98]

I recently rejoined the ranks of GN owner with the purchase of two project cars.

I'm not sure of the gear ratio that I have but I'm curious as to how fast the engine should be turning while I'm on the freeway doing 65.

I just checked while coming home and saw that it showed around 2600.

Is that about right?

 

[fubar2.5]

You can't use the factory tach for anything.However if you are using something accurate it's about 400 rpm high.

 

[imjoesnuffy]

Mine is around 2150ish???

Is your torque convertor locking? While driving around 60mph, tap the brakes while maintaining your foot on the gas. You should hear the rpms rise if it is locked.

 

[syclone98]

Wow, is the factory tach really off that much?

All I know about the transmission is that the guy put a shift kit in it but I doubt that'd explain the high RPMs on the freeway.

Other than the converter possibly not locking, what other reason might it be revving so high?

 

[8UWITH6]

What size is the tire in the rear of the car? And yes, the factory tach can be off that much. Mine shows 3500 at 70mph in OD

 

[syclone98]

They're 245 50/16's.

It appears as though my converter isn't locking up so I'm going to try the "paperclip" method tonight. If that doesn't work then I'll probably start looking for other possible causes. I just hope that the converter itself isn't a non-lockup type as I don't feel like pulling the tranny right now.

 

[8UWITH6]

Make sure the cruise/lock up switch above the brake light switch under the dash is adjusted properly. HTH

 

[usetaboost]

Your chip could be a non-lockup also!

 

[BLACK6PACK]

Most of the factory tachs I've seen read 5000 rpm while cruising through a parking lot.

 

[usetaboost]

WHat I think is special is that the boost guage reads 5psi when you blip the throttle

 

[fc227]

Mine reads around 2K @ 65MPH.

 

[SITHV6]

Kenne Bell newsletter states...

I have an old Kenne Bell newsletter/tech tips that stated the factory cam design was to allow 60(65?)mph at only 1800. this sound right?

 

[syclone98]

I started troubleshooting my converter lockup and even when I use the paperclip method it didn't work so I'll probably start tearing things apart this weekend.

 

[usetaboost]

Check the chip first. Good chance its a non-lock up!

 

[mikestertwo]

Does the car have a lockup converter in it?

 

[syclone98]

Unfortunately I have no way of knowing whether it's a lockup converter or not. I do however have a stock chip from the second car that I can try in there to see if it makes a difference or not.

 

[GNX243]

Tcc

Same problem with mine...TCC not engaging. Turned out orevious owner had installed a 155 thermostat. Make sure you are above 160.

 

[syclone98]

I've got an aftermarket temp gauge installed and it's showing 180 so that probably isn't the issue in my case.