Best gear for 9.90

Tom Goldman · 04-03-2021, 01:27 PM

Like Charlie ,I run Select converters . I went to 4.56 gears from 4.29 in my Vette which weighs in at 2400# .
I picked up 2 mph with an increase of 250 trap rpm .
converter efficiency went from 10% slip to 5-6%. AND very importantly , the converter temperature dropped way down when coming off the stop.
Since Charlie's car is a '27 Roadster, one of the hardest cars to get MPH out of I'm not surprised by the lack of improvement in speed.
I would defiantly recommend 4.56 gears in your car.
Racers get too hung up on trap rpm's , if your engine is still pulling at the stripe ,let it eat !

Keith 944 · 04-03-2021, 08:06 PM

^^^^^^this

Dano · 04-16-2021, 04:56 PM

Quote:

Originally Posted by Tom Goldman

Like Charlie ,I run Select converters . I went to 4.56 gears from 4.29 in my Vette which weighs in at 2400# .
I picked up 2 mph with an increase of 250 trap rpm .
converter efficiency went from 10% slip to 5-6%. AND very importantly , the converter temperature dropped way down when coming off the stop.
Since Charlie's car is a '27 Roadster, one of the hardest cars to get MPH out of I'm not surprised by the lack of improvement in speed.
I would defiantly recommend 4.56 gears in your car.
Racers get too hung up on trap rpm's , if your engine is still pulling at the stripe ,let it eat !

Did the cars reaction improve?

Charlie Yannetti · 06-10-2021, 07:48 AM

In my combination, the gear change didn't seem to affect my reaction time.. I didn't change any numbers in the box..

Dano · 06-10-2021, 10:10 AM

Quote:

Originally Posted by Charlie Yannetti

In my combination, the gear change didn't seem to affect my reaction time.. I didn't change any numbers in the box..

No improvement on my cars reaction either with a 4.10 to 4.57 change.

04-03-2021, 01:27 PM	#1
Tom Goldman VIP Member Join Date: Jan 2003 Location: Allentown,PA Posts: 2,478 Likes: 894 Liked 886 Times in 238 Posts	Re: Best gear for 9.90 Like Charlie ,I run Select converters . I went to 4.56 gears from 4.29 in my Vette which weighs in at 2400# . I picked up 2 mph with an increase of 250 trap rpm . converter efficiency went from 10% slip to 5-6%. AND very importantly , the converter temperature dropped way down when coming off the stop. Since Charlie's car is a '27 Roadster, one of the hardest cars to get MPH out of I'm not surprised by the lack of improvement in speed. I would defiantly recommend 4.56 gears in your car. Racers get too hung up on trap rpm's , if your engine is still pulling at the stripe ,let it eat ! __________________ Tom Goldman 1500 SG , 1506 STK

04-03-2021, 08:06 PM	#2
Keith 944 VIP Member Join Date: Feb 2006 Location: Dela-where? Posts: 2,195 Likes: 1,163 Liked 1,885 Times in 578 Posts	Re: Best gear for 9.90 ^^^^^^this __________________ KEITH MAYERS 2-1/2 X somebody Still many X nobody

06-10-2021, 07:48 AM	#4
Charlie Yannetti Senior Member Join Date: Jan 2005 Location: Alpine, NJ Posts: 568 Likes: 188 Liked 192 Times in 83 Posts	Re: Best gear for 9.90 In my combination, the gear change didn't seem to affect my reaction time.. I didn't change any numbers in the box..