Best way to slow car
#1
Junior Member
APPRENTICE
Thread Starter
Join Date: Jul 2007
Posts: 12
Best way to slow car
I have a sbc w/pg and 5.13 rear that runs consistent 5.60's.I am thinking of slowing it down to run a heads up 5.90 class,what is best way to go,if changing rear how far would I go,thanks for any input.
#4
Senior Member
DYNO OPERATOR
Join Date: Jan 2004
Location: central Illinois
Posts: 459
Best way
I have had this issue for 2 seasons.
Slowing a 5.90 car down to 6.40+ to avoid having to get a license again and the associated cost.
I went thru 10 ideas.
Finally used a homemade restrictor plate under the carb at a RJ members suggestion. Slowed to 6.28 with a 4 hole 1 3/4" plate for a 2" dominator carb. It works consistanly. Rather than making a few more to get slower and having to pull the carb each change, I bought an E Z Plate system. It has a 1" spacer with a cut out in the side to slide in 1 of 20 supplied plates. A simple 1 bolt cover comes off and a change can be made in 30 seconds. I haven't tried it yet, but a lot of Super class cars use them. It is very high quality looking, but is a little salty at $350. I think this will be the answer.
No changes to your tune up are required.
Slowing a 5.90 car down to 6.40+ to avoid having to get a license again and the associated cost.
I went thru 10 ideas.
Finally used a homemade restrictor plate under the carb at a RJ members suggestion. Slowed to 6.28 with a 4 hole 1 3/4" plate for a 2" dominator carb. It works consistanly. Rather than making a few more to get slower and having to pull the carb each change, I bought an E Z Plate system. It has a 1" spacer with a cut out in the side to slide in 1 of 20 supplied plates. A simple 1 bolt cover comes off and a change can be made in 30 seconds. I haven't tried it yet, but a lot of Super class cars use them. It is very high quality looking, but is a little salty at $350. I think this will be the answer.
No changes to your tune up are required.
#8
Senior Member
RACING JUNKIE
Join Date: Sep 2007
Posts: 4,137
I have the same issue as my car will run in the 5's but is not certified nor am I licensed...just make an adjustable throttle stop to put under the pedal and play with it until you get it right....you could also use a solid stop up on the carb.....the threaded rod under the pedal is cheap and crude but effective.
#9
Some sort of throttle stop under the pedal is something I put on every car i build. The main reason is when you're 'pushing' for that last ounce of speed, you are not stressing out any of the linkage or stretching the cable. I make sure that it is adjusted at WOT and then can have the option of slowing it down if desired.
A lot of stuck throttle issues can be traced back to over-centered, deformed linkage, stuck wide open throttle blades, or frayed cables from over stressing, and no solid stop on the gas pedal.
A lot of stuck throttle issues can be traced back to over-centered, deformed linkage, stuck wide open throttle blades, or frayed cables from over stressing, and no solid stop on the gas pedal.