Restrictor plates? How much ET can you kill?

Anyone using restrictor plates like the Willy's carb adjustable ones? How much ET can you kill on a high 9 second car? My car has gone 9.77. If I wanted to set it up for a 10.0 index could I do it with just the restrictor?

I use to use a bolt stop on the carb to get the ET where I wanted to your not trying to scrub that much et to get 10.00

You could surely get your 9.77 to 10.0 with plates. But here is another perspective.
My advice is to make your own fixed restrictor plates. Size is up to you to test. Make 3 or 4 different ones.
Go test and find one that gets you within a tenth of your desired ET.
From there, leave the plate alone and dial the car with weight and shift point...shift point being the "fine" adjustment.
Here is why.
You are strapped in and there is a delay. Your weather station tells you that things are changing, or maybe you see the flags change....went from a tail to head wind.
If you are dialing totally with a plate...no matter what brand, you are screwed.
If you make your fine adjustment with shift point, you simply reach down and bump the shift up or down to put it dead on...
Just my input...
Keith

the Coug wrote:I use to use a bolt stop on the carb to get the ET where I wanted to your not trying to scrub that much et to get 10.00

I did the same thing years ago. Slowed a 9.23 to a 9.90 easily. Keith makes a good point...there are a lot of external factors that will affect e.t.

Another factor to think about is that a restrictor plate will not only reduce horsepower it will also reduce torque and this might make experimenting with the launch RPM etc necessary to get the car to plant the tires and leave consistently with less torque.

^^^^^^^^^^^^^^^^Very true^^^^^^^^^^^^^^^^^This won't just slow the e.t.   It'll murder the 60'...maybe not too bad if you're only slowing the car a little, In our case, the car would run pretty much dead-on, but it left like a turd.

Probably the thing to do if you're serious about it would be to re gear the car so that the car can 60ft about the same with the reduced torque. I think it would be possible to make it 60ft about the same but it would go a lot slower on the other end because the engine will be farther past peak HP.

512Fairlane wrote:Anyone using restrictor plates like the Willy's carb adjustable ones?  How much ET can you kill on a high 9 second car?  My car has gone 9.77.  If I wanted to set it up for a 10.0 index could I do it with just the restrictor?

If a variable "throttle stop" is not legal, The best way to tune a car to go slower is to restrict the exhaust side and the maximum power while retaining the lower end torque so, the starting line characteristics are not greatly changed.

It doesn't look like Willy's makes one for a 4500 series carb but I'm liking the EZ-plate system here. http://www.restrictorplate.com/ Little pricy though.

just get you a throttle stop http://www.biondoracing.com/category/throttle-stops.html set it and forget it...

Index classes likely won't allow any throttle controls other than a solid type stop or the plates. Can't be programmable or adjusted from driver's seat (driver's foot excepted). At least around here they won't.

if your 4500 Dommy has external throttle linkage you could disconnect the secondary's, they are good for 3 to 4 tenths

He's trying to lose about .230 sec.

512Fairlane wrote:It doesn't look like Willy's makes one for a 4500 series carb but I'm liking the EZ-plate system here.  http://www.restrictorplate.com/  Little pricy though.

That's all I use. 9.40 car slowed down to a 10.0. I have timing pulled on top of it and lower shift points. Each plate is worth .02 in et. It's easy. I was hoping to make it down to 5.90 class but only 6.01 now. Guess I'm stuck in 10.0 again. I also have 100lbs in the trunk.

Once you get some weather info documented I can usually come off the trailer between 9.97 and 10.03.

Love the EZ plate. If I remember right each plate the hole was .005 smaller.

Thanks for all the responses. I think I might try the EZ plate. I've tried just a bolt under the pedal before and the car just wouldn't react. My 9.77 was in really good air so I have a feeling most of the time I won't have to kill as much ET. I like the ability to tune it by changing plates.

He will have some questions for you when you call.
Best et
Typical track DA
I have about 18 plates because I keep lightening the car. He will start you out with ten I think. I may ask him myself if I could get some "in between" plates.
In other words if I ran 10.01 then one more plate smaller may put me at 9.99. I'd like to have one between those two.

Good luck and just let me know if you need any help with it.

Yeah... It all boils down to test...test..test.
You are so close to the 10.0, shift point alone may do the trick, and that doesn't hurt your reaction time and 60'. (Or wallet)
I have burned up a few drums of alky finding the various combos to make my car that runs 8.80'ish to go 9.0...9.50...and 10.0 indexes.
You will find the perfect deal.
Good luck!
Keith

Thanks Keith. I've played with shift points before but I'm already only shifting at 6000. It doesn't seem to change my combination much. I may try some other things before I spring for the plates. But we will see.

Take a look at ET Genie Restrictor Plate System.

Mike runs Hot Rod reunion @ Bowling Green. It is a Nostalgia event that doesn't allow any EFI,or any electronic timing devices that take out timing electronically. Any manual operated devices such as weight placement,restrictor plates,or foot operated devices are allowed.

512Fairlane wrote:It doesn't look like Willy's makes one for a 4500 series carb but I'm liking the EZ-plate system here.  http://www.restrictorplate.com/  Little pricy though.

A buddy of mine uses the EZ-Plate along with some other guys here in Northeast,Ohio who run the RRA races.They have 8.90,9.90,10.50 and 11.50 classes i think my buddies Camaro runs 9.5's-9.60's and he slows it down with the EZ-Plate to run the 9.90 class.

I'm comparing the ET Genie to the EZ-Plate. I like how the ET Genie does not require you to have a stack of plates laying around but it seems like the way it closes toward the center would affect fuel distribution. Since the EZ-plate set up keeps each hole centered under the butterflies it seems like it would be better. Any thoughts?

Not sure about the ET Genie but the guys i know who use the EZ Plates seem to like them.