1/4 Mile RPM's

[cmokem]

What kind of rpms should a basic recipe car see crossing the 1/4 mile line. I was seeing 5000-5100 with my Nittos Tires and locked converter...does this sound right??

TIA
Bob

 

[hot6-231]

What size Nitto's?? Big difference in rpm's between 26"- 28" tires??

 

[azgn]

it sounds like you have some "slippage".....I go thru the traps at 5100 with 27" tires at 122 mph (converter locked....5775 unlocked)

 

[cmokem]

I was running 275-50 nittos on that run with the converter locked. This weekend I put 275 60's on and my MPH suffered almost 5 mph lower than with the Nittos....RPMs were down too.

Im thinking were the tcc locks up 75 mph may be putting a large load on the motor with the 28" tires....the 1/8 mile speeds are only 1 mph off. The car ran good nothing on tlink to indicate a problem...any thoughts

Thanks
Bob

 

[UNGN]

With a 26" tire, 109 mph is 5000 RPM with the converter locked.

Rpms will be about 8% with 275/60's vs. 275/50 nittos.

If your long block is still stock, I would look for something else to cause a 5 mph drop going from 275/50's to 275/60's, like the weather or knock. Especially if the 1/8 mile mphs were similar.

My TCC locks up around 35 mph. The additonal load can lead to knock, but doesn't slow the car down if no knock occurs.

 

[cmokem]

Thanks for the replies...
The car seemed to run fine...no knock 20 psi of boost 1550 on the egt. That is consistent of how the car runs all the time. The weather was chilly (45 Degrees) and clear. Im going to try the Nittos next week to rule out any car problems.

Bob