Drag Racing Tech
Sponsored by:
Sponsored by:

Want to slow car down

Thread Tools
 
Search this Thread
 
Old Mar 25, 2012 | 06:43 PM
  #1  
Rpayne41985's Avatar
Thread Starter
10 Second Club
15 Year Member
Liked
iTrader: (12)
 
Joined: Oct 2010
Posts: 378
Likes: 12
Default Want to slow car down

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.
Reply
Old Mar 25, 2012 | 07:59 PM
  #2  
subhumanzz's Avatar
9 Second Club
iTrader: (46)
 
Joined: May 2006
Posts: 1,037
Likes: 0
From: Fredericksburg, VA
Default

are you launching on a transbrake?
Reply
Old Mar 25, 2012 | 09:39 PM
  #3  
94Z28rag's Avatar
TECH Fanatic
iTrader: (10)
 
Joined: Jun 2008
Posts: 1,217
Likes: 1
From: West Chester, PA
Default

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.
Reply
Old Mar 25, 2012 | 10:02 PM
  #4  
Hector's Avatar
On The Tree
 
Joined: Feb 2006
Posts: 115
Likes: 0
From: Oaktown, CA
Default

Isn't this what bracket racers do? How do they do it? Throttle stop? Restrictor plate?
Reply
Old Mar 25, 2012 | 10:26 PM
  #5  
3DFORMULA's Avatar
TECH Enthusiast
iTrader: (4)
 
Joined: May 2007
Posts: 625
Likes: 0
Default

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
Reply
Old Mar 26, 2012 | 09:37 AM
  #6  
fatboyzcamaro's Avatar
Launching!
iTrader: (7)
 
Joined: Sep 2008
Posts: 230
Likes: 0
From: MARYLAND
Default

Man u will b surprise how much u can slow down by short shifting. It works.
Reply
Old Mar 26, 2012 | 10:30 AM
  #7  
chasgiv3's Avatar
9 Second Club
iTrader: (1)
 
Joined: Nov 2001
Posts: 782
Likes: 0
From: Chicago
Default

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.
Reply
Old Mar 26, 2012 | 12:39 PM
  #8  
TurboStangJON's Avatar
10 Second Club
iTrader: (27)
 
Joined: Mar 2009
Posts: 810
Likes: 1
From: Kissimmee, FL / Vienna, VA
Default

You can accomplish slowing the car down a variety of ways. I'd add some weight then lower the shift points.
Reply
LS1 Tech Stories

The Best V8 Stories One Small Block at Time

story-0

6 Gifts Neither Your Dad Nor Grad Will Shove Into the 'Trinket Drawer'

 Brett Foote
story-1

Topdon ONE vs. Artidiag 800 BT2: Which is the Diagnostic Tablet For You?

 Pouria Savadkouei
story-2

Gas Monkey Built a 6-Wheel Ferrari Testarossa With a Corvette LT4 Engine

 Verdad Gallardo
story-3

7 Most Reliable High-Performance Engines GM Has Ever Built

 Verdad Gallardo
story-4

Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin

 Verdad Gallardo
story-5

6 Common C5 Corvette Failures and What's Involved In Repairing Them

 Pouria Savadkouei
story-6

Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph

 Verdad Gallardo
story-7

Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked

 Pouria Savadkouei
story-8

Top 10 Most Powerful Chevy Trucks Ever Made!

 
story-9

Hennessey's New Supercharged Silverado ZR2 Has 700 HP

 Verdad Gallardo
Old Mar 26, 2012 | 01:06 PM
  #9  
Rpayne41985's Avatar
Thread Starter
10 Second Club
15 Year Member
Liked
iTrader: (12)
 
Joined: Oct 2010
Posts: 378
Likes: 12
Default

Im foot braking the car and it is a manual valve body
Reply
Old Mar 26, 2012 | 01:20 PM
  #10  
chasgiv3's Avatar
9 Second Club
iTrader: (1)
 
Joined: Nov 2001
Posts: 782
Likes: 0
From: Chicago
Default

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.
Reply
Old Mar 26, 2012 | 01:30 PM
  #11  
BlackScreaminMachine's Avatar
Internet Mechanic
20 Year Member
iTrader: (17)
 
Joined: May 2005
Posts: 9,830
Likes: 2
From: Wallingford CT
Default

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.
Reply
Old Apr 2, 2012 | 11:29 PM
  #12  
Big Al's Avatar
TECH Resident
iTrader: (1)
 
Joined: May 2005
Posts: 970
Likes: 1
Default

Put in a simple adjustable throttle stop. End of problem.

Al 95 Z28
Reply
Old Apr 3, 2012 | 04:54 AM
  #13  
subhumanzz's Avatar
9 Second Club
iTrader: (46)
 
Joined: May 2006
Posts: 1,037
Likes: 0
From: Fredericksburg, VA
Default

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.
Reply
Old Apr 3, 2012 | 07:17 AM
  #14  
BlackScreaminMachine's Avatar
Internet Mechanic
20 Year Member
iTrader: (17)
 
Joined: May 2005
Posts: 9,830
Likes: 2
From: Wallingford CT
Default

Originally Posted by Big Al
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
Reply
Old Apr 3, 2012 | 10:35 AM
  #15  
TA1364's Avatar
11 Second Club
iTrader: (11)
 
Joined: Aug 2007
Posts: 1,779
Likes: 3
From: Dayton, OH
Default

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%.
Reply
Old Apr 3, 2012 | 02:10 PM
  #16  
subhumanzz's Avatar
9 Second Club
iTrader: (46)
 
Joined: May 2006
Posts: 1,037
Likes: 0
From: Fredericksburg, VA
Default

Originally Posted by TA1364
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.
Reply
Old Apr 3, 2012 | 05:34 PM
  #17  
zracer323's Avatar
12 Second Club
iTrader: (12)
 
Joined: Oct 2007
Posts: 1,340
Likes: 1
From: Dayton, Ohio
Default

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.
Reply
Old Apr 5, 2012 | 07:02 PM
  #18  
Big Al's Avatar
TECH Resident
iTrader: (1)
 
Joined: May 2005
Posts: 970
Likes: 1
Default

Originally Posted by BlackScreaminMachine
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
Reply
Old Apr 6, 2012 | 06:43 AM
  #19  
BlackScreaminMachine's Avatar
Internet Mechanic
20 Year Member
iTrader: (17)
 
Joined: May 2005
Posts: 9,830
Likes: 2
From: Wallingford CT
Default

Originally Posted by Big Al
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/sh...d.php?t=451426

Here is an example from MIR.

See post #12

Another one,

http://kansasdragway.com/racer-secti...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.
Reply
Old Apr 6, 2012 | 06:49 PM
  #20  
Big Al's Avatar
TECH Resident
iTrader: (1)
 
Joined: May 2005
Posts: 970
Likes: 1
Default

Originally Posted by BlackScreaminMachine
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/sh...d.php?t=451426

Here is an example from MIR.

See post #12

Another one,

http://kansasdragway.com/racer-secti...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
Reply




All times are GMT -5. The time now is 01:44 PM.

story-0
6 Gifts Neither Your Dad Nor Grad Will Shove Into the 'Trinket Drawer'

Don't get dad new socks or a grill brush this year.

By Brett Foote | 2026-06-04 18:13:20


VIEW MORE
story-1
Topdon ONE vs. Artidiag 800 BT2: Which is the Diagnostic Tablet For You?

Slideshow: We take a close look at the ONE and Artidiag 800BT2 diagnostic tools from Topdon and the reasons to buy one over the other.

By Pouria Savadkouei | 2026-05-28 11:05:11


VIEW MORE
story-2
Gas Monkey Built a 6-Wheel Ferrari Testarossa With a Corvette LT4 Engine

Slideshow: The controversial Ferrari F6 swaps its original flat-12 for a Corvette Z06-derived LT4 V8 and sends power to four rear wheels through a custom-built drivetrain.

By Verdad Gallardo | 2026-05-26 18:23:54


VIEW MORE
story-3
7 Most Reliable High-Performance Engines GM Has Ever Built

Slideshow:These GM engines didn't just make huge power, they survived abuse, boost, track days, and six-digit mileage with a reputation for refusing to quit.

By Verdad Gallardo | 2026-05-21 16:45:27


VIEW MORE
story-4
Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin

Slideshow: This heavily modified 1971 Camaro mixes classic muscle car styling with a fifth-generation Camaro interior and modern LS3 power.

By Verdad Gallardo | 2026-05-12 18:06:42


VIEW MORE
story-5
6 Common C5 Corvette Failures and What's Involved In Repairing Them

Slideshow: From wobbling harmonic balancers to failed EBCMs, these are the issues that define long-term C5 ownership and what repairs typically involve.

By Pouria Savadkouei | 2026-05-07 18:44:57


VIEW MORE
story-6
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph

Slideshow: A modern Camaro transformed into a retro icon, this limited-run "Bandit" build blends nostalgia with brute force in a way few revivals manage.

By Verdad Gallardo | 2026-04-21 13:57:02


VIEW MORE
story-7
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked

Slideshow: Cadillac didn't just crash the high-performance luxury vehicle party, it showed up loud, supercharged, and occasionally a little unhinged...

By Pouria Savadkouei | 2026-04-16 10:05:15


VIEW MORE
story-8
Top 10 Most Powerful Chevy Trucks Ever Made!

Slideshow: Top ten most powerful Chevy trucks ever made

By | 2026-03-25 09:22:26


VIEW MORE
story-9
Hennessey's New Supercharged Silverado ZR2 Has 700 HP

Slideshow: Hennessey has turned the Silverado ZR2 into a 700-hp off-road monster with supercharged V8 power and a limited production run.

By Verdad Gallardo | 2026-03-24 18:57:52


VIEW MORE