View Full Version : Want to slow car down


Rpayne41985
03-25-2012, 06:43 PM
my car runs around 11.00's all day long but I dont have the money for a cage right now and I want to keep it around 11.50's. I shift the car @ 6800, im wondering if I short shift it if it would slow down to around 11.50's. Do you guys have any idea where I could shift it at to slow it down or do you guys know a differnt way to slow it down and still keep it consistant? There's a race this weekend that I want to run so any help would be appreciated.

subhumanzz
03-25-2012, 07:59 PM
are you launching on a transbrake?

94Z28rag
03-25-2012, 09:39 PM
You could add weight, but you'd need about 500 lbs to slow a half second, so that's not realistic.

Short shifting will help, but you'll just need to be consistent with the new shift points. You'll need a few runs to dial it in if you're making changes...but you could start but lowering your shifts to 6,000 and see how much it knocks off. If you need more, keep going lower.

Hector
03-25-2012, 10:02 PM
Isn't this what bracket racers do? How do they do it? Throttle stop? Restrictor plate?

3DFORMULA
03-25-2012, 10:26 PM
Launch softer. Give up a couple tenths on the 60ft and shift lower like previously stated. More air in the tires will help you find a new softer launch. Get something consistent and you may get away with adding 100-150lbs only

fatboyzcamaro
03-26-2012, 09:37 AM
Man u will b surprise how much u can slow down by short shifting. It works.

chasgiv3
03-26-2012, 10:30 AM
Install a 2 step on the car so you launch consistantly.
Is the TH350 a manual valve body? I assume it it. If so you need to experiment with a shift light at certain RPM's in order to get your number.
Then you can do 11.5's all day with consistancy. I can slow my car down via boost control if I'm in a situation that requires bracket racing and I launch off a very low RPM on the 2-step.

TurboStangJON
03-26-2012, 12:39 PM
You can accomplish slowing the car down a variety of ways. I'd add some weight then lower the shift points.

Rpayne41985
03-26-2012, 01:06 PM
Im foot braking the car and it is a manual valve body

chasgiv3
03-26-2012, 01:20 PM
Perfect. You should be able to foot brake it to say 2000RPM set your shift light to 5000RPM and make a test run. See where you're at and adjust the shift light RPM lower or higher by say 200RPM until you get the exact number that you wanted. The timing of your shifts need to be consistant with the light. This should get you there.

BlackScreaminMachine
03-26-2012, 01:30 PM
Like said many options, if iit has some timing in it, take it out. It would slow the car in all aspects so for those who street drive, add balast to where you want it. Just need to reference the car based on D/A and track condidtions if thats a concern.

Big Al
04-02-2012, 11:29 PM
Put in a simple adjustable throttle stop. End of problem.

Al 95 Z28

subhumanzz
04-03-2012, 04:54 AM
I run in an index race once a month (6.50 index). My car runs high .20- low .30's and I pull about 6* of timing from 6-8k rpms pending on weather conditions and it will slow it down to a very low .50. This is the easiest thing to do if you have some tuning software. For me it was a plus because I didn't have to change my driving regimen at all.

BlackScreaminMachine
04-03-2012, 07:17 AM
Put in a simple adjustable throttle stop. End of problem.

Al 95 Z28

Not all classes allow for that, or it puts them in "electronics" and you field with cars that are more apt to beat you. It all depends if your local track supports a "Foot-brake" class and a "Electronics" class

TA1364
04-03-2012, 10:35 AM
I'm in the same boat, need to slow down from 1150s to 1200s. Dont really want to pull a bunch of timming or add a bunch of weight then its a turd off the line. I was thinking of something to limit how far the the tb opens. Something like 80%-85%.

subhumanzz
04-03-2012, 02:10 PM
I'm in the same boat, need to slow down from 1150s to 1200s. Dont really want to pull a bunch of timming or add a bunch of weight then its a turd off the line. I was thinking of something to limit how far the the tb opens. Something like 80%-85%.

you dont pull the timing from the lower rpm range.

zracer323
04-03-2012, 05:34 PM
I pulled 5 degrees of timing and added about 60 lbs of weight to slow mine down about .3 to run the 12.50 index at the Shootout last year.

Big Al
04-05-2012, 07:02 PM
Not all classes allow for that, or it puts them in "electronics" and you field with cars that are more apt to beat you. It all depends if your local track supports a "Foot-brake" class and a "Electronics" class

What, they don't allow adjustable throttle linkage? Better show me that in a rule book. We use 1/4 28 rod and an adjustable coupling nut to make the linkage longer or shorter. We can slow down a full second and still stay consistent.

Al 95 Z28

BlackScreaminMachine
04-06-2012, 06:43 AM
What, they don't allow adjustable throttle linkage? Better show me that in a rule book. We use 1/4 28 rod and an adjustable coupling nut to make the linkage longer or shorter. We can slow down a full second and still stay consistent.

Al 95 Z28

Like I said, may vary from track to track, and its class dependant. LVD used to post their rules and right now the site has not been updated for 2012.

http://www.yellowbullet.com/forum/showthread.php?t=451426

Here is an example from MIR.

See post #12

Another one,

http://kansasdragway.com/racer-section/rules-for-the-summit-racing-series/

I would think your fine as its not shutting the car down, more like restricting. I would think thats a good question for a track tech guy.

Big Al
04-06-2012, 06:49 PM
Like I said, may vary from track to track, and its class dependant. LVD used to post their rules and right now the site has not been updated for 2012.

http://www.yellowbullet.com/forum/showthread.php?t=451426

Here is an example from MIR.

See post #12

Another one,

http://kansasdragway.com/racer-section/rules-for-the-summit-racing-series/

I would think your fine as its not shutting the car down, more like restricting. I would think thats a good question for a track tech guy.

Electronic limiters are a different story. You can weld a bolt under the gas pedal and use a coupling nut to adjust how far the pedal can go down. There are a lot of ways to do it.

Al 95 Z28 still trying to go faster:)