Setting Throttle Stop RPM

NHRA1926 · 11-30-2023, 11:30 AM

What is the easiest way to set the rpm on the throttle stop while not actually driving the car down the track? I'd like to try to set it while running the car on jack stands preferably.

sst5167 · 11-30-2023, 07:03 PM

To be very specific on how to do it, we need to know a little more about your set up. But the short of it is, all you need to do is reverse the air or polarity of the throttle stop so it closes. Pull the car into low gear, set the trans brake, a go to wide open throttle. The RPM the car goes to should be very close to what it is on the track.

Tom Goldman · 12-01-2023, 12:22 AM

I use a toggle switch bypass to dump the air at the stop . I always warm the trans to 180-200 degrees before checking the rpm. As Keith said set the brake and wack the throttle . I do a 2 second hold . I have a digital dash so it's easy to see the exact rpm . I also data record the test to confirm the rpm .
If you have a properly calibrated carb you should have a nice flat line on the stop rpm .
My test rpm matches my track rpm within 10-15 rpm.

Charlie Yannetti · 12-04-2023, 01:01 PM

The info you have been given thus far is pretty good.. please remember to get the motor and trans up to your normal operating temperatures.. THIS IS IMPORTANT!!.. convertors are known to vary in stall rpm with different temperatures, which will affect your cruise rpm.. also, Tom's 2 second hold while on the brake is equally important, as some convertors are known to creep up in rpm.. it may initially hit where you want it, but move 50 to 100 rpm on the hold.. adjust off the HOLD..

As I'm always told "The Track Is The Best Dyno".. a data recorder, or RacePak, will always show you where you're really at...

11-30-2023, 11:30 AM	#1
NHRA1926 Member Join Date: Dec 2015 Location: Bowling green, Ky Posts: 220 Likes: 12 Liked 164 Times in 54 Posts	Setting Throttle Stop RPM What is the easiest way to set the rpm on the throttle stop while not actually driving the car down the track? I'd like to try to set it while running the car on jack stands preferably.

11-30-2023, 07:03 PM	#2
sst5167 Junior Member Join Date: Dec 2009 Posts: 52 Likes: 17 Liked 17 Times in 9 Posts	Re: Setting Throttle Stop RPM To be very specific on how to do it, we need to know a little more about your set up. But the short of it is, all you need to do is reverse the air or polarity of the throttle stop so it closes. Pull the car into low gear, set the trans brake, a go to wide open throttle. The RPM the car goes to should be very close to what it is on the track.

12-01-2023, 12:22 AM	#3
Tom Goldman VIP Member Join Date: Jan 2003 Location: Allentown,PA Posts: 2,453 Likes: 821 Liked 774 Times in 220 Posts	Re: Setting Throttle Stop RPM I use a toggle switch bypass to dump the air at the stop . I always warm the trans to 180-200 degrees before checking the rpm. As Keith said set the brake and wack the throttle . I do a 2 second hold . I have a digital dash so it's easy to see the exact rpm . I also data record the test to confirm the rpm . If you have a properly calibrated carb you should have a nice flat line on the stop rpm . My test rpm matches my track rpm within 10-15 rpm. __________________ Tom Goldman 1500 SG , 1506 STK

12-04-2023, 01:01 PM	#4
Charlie Yannetti Senior Member Join Date: Jan 2005 Location: Alpine, NJ Posts: 564 Likes: 184 Liked 185 Times in 81 Posts	Re: Setting Throttle Stop RPM The info you have been given thus far is pretty good.. please remember to get the motor and trans up to your normal operating temperatures.. THIS IS IMPORTANT!!.. convertors are known to vary in stall rpm with different temperatures, which will affect your cruise rpm.. also, Tom's 2 second hold while on the brake is equally important, as some convertors are known to creep up in rpm.. it may initially hit where you want it, but move 50 to 100 rpm on the hold.. adjust off the HOLD.. As I'm always told "The Track Is The Best Dyno".. a data recorder, or RacePak, will always show you where you're really at...