Organized Drag Racing and Autocross Drag racing and autocross discussions and questions. Techniques, tips, suggestions, and "what will I run?" questions.

Stall Speed?

Thread Tools
 
Search this Thread
 
Old Mar 3, 2008 | 11:55 PM
  #1  
thumper115's Avatar
Thread Starter
Junior Member
 
Joined: Jan 2008
Posts: 43
Likes: 0
From: Hayti, MO
Car: 1972 SS Nova, 1991 Camaro drag only
Engine: Stock 350, 355 w/12.5's
Transmission: 350 auto's
Axle/Gears: 3.55, 3.73
Stall Speed?

I went to the track yesterday and I have a 4500 stall in the car but it would only stall at 3,000 due to sliding the front tires. It is a new stall and Transmission, a 350 from Summitt. I have front runners with 165R15's on front. It is a stock suspension, brakes and all. I have not touched any of the brakes yet. What will help get it to not slide the front wheels.? It went 8.05 in the 1/8th mile. I have some wider tires I can install very easily.
Reply
Old Mar 4, 2008 | 12:03 AM
  #2  
AlkyIROC's Avatar
Moderator
25 Year Member
Liked
 
Joined: Jul 1999
Posts: 17,271
Likes: 171
From: 51°N 114°W, 3500'
Car: 87 IROC L98
Engine: 588 Alcohol BBC
Transmission: Powerglide
Axle/Gears: Ford 9"/31 spline spool/4.86
Re: Stall Speed?

You will never reach full stall speed by holding the vehicle with the brakes. The only way to reach full stall speed is with a transbrake.

Based on your 8.05 1/8 mile time, I think you have way too much stall speed for whatever your engine specs and your diff gear ratio are.
Reply
Old Mar 4, 2008 | 12:09 AM
  #3  
thumper115's Avatar
Thread Starter
Junior Member
 
Joined: Jan 2008
Posts: 43
Likes: 0
From: Hayti, MO
Car: 1972 SS Nova, 1991 Camaro drag only
Engine: Stock 350, 355 w/12.5's
Transmission: 350 auto's
Axle/Gears: 3.55, 3.73
Re: Stall Speed?

Originally Posted by Stephen 87 IROC
You will never reach full stall speed by holding the vehicle with the brakes. The only way to reach full stall speed is with a transbrake.

Based on your 8.05 1/8 mile time, I think you have way too much stall speed for whatever your engine specs and your diff gear ratio are.

I am running a 3.73 gear ratio, with a 355 with 12.5:1 compression ratio and a 600 degree lift cam. I am actually sliding the front tires through the lite at 3,000. Most of the time in my Nova at least I could get close to advertised stall as in 3,500 I get like 3,000.
Reply
Old Mar 4, 2008 | 10:59 AM
  #4  
automec's Avatar
Member
 
Joined: Nov 2002
Posts: 390
Likes: 0
From: idaho falls id.
Car: 82 Z-28
Engine: 408
Transmission: TH-400
Axle/Gears: 4.11
Re: Stall Speed?

i can only foot brake the stall on my car to 2200 rpm . on the trans brake it hits 5300 rpm.
Reply
Old Mar 6, 2008 | 07:19 PM
  #5  
joeblue83's Avatar
Senior Member
iTrader: (8)
 
Joined: Aug 2007
Posts: 1,341
Likes: 0
From: Southern Wisconsin
Car: 1988 Camaro
Engine: 383 Stroker
Transmission: Probuilt 700 R4
Axle/Gears: 3.73
Re: Stall Speed?

If you were to foot brake it with new brake kits all around what RPM should you be holding at. At mine it breaks at 1000rpm. Kind of weird. Would putting a brake booster help?
Reply
Old Mar 6, 2008 | 07:26 PM
  #6  
xpndbl3's Avatar
Supreme Member
iTrader: (5)
 
Joined: Jan 2002
Posts: 13,622
Likes: 5
From: Orland Park, IL
Car: 1984 Z28
Engine: SLOW carbed ls
Transmission: TH400 with brake, 8" PTC converter
Axle/Gears: moser 9" 4.11
Re: Stall Speed?

i never have had to foot brake a car beyond 2000 rpm at the most, the rest is all flash speed and traction. my converter hits 3800 or so flash speed the engine rpm goes up from there. No reason to try to hold it to 3000 or higher with a footbrake, your brakes will never hold it.
Reply
Old Mar 6, 2008 | 08:35 PM
  #7  
87_TA's Avatar
TGO Supporter
 
Joined: Dec 2001
Posts: 2,308
Likes: 0
From: ELIZABETH,PA,USA
Re: Stall Speed?

Originally Posted by thumper115
I went to the track yesterday and I have a 4500 stall in the car but it would only stall at 3,000 due to sliding the front tires. It is a new stall and Transmission, a 350 from Summitt. I have front runners with 165R15's on front. It is a stock suspension, brakes and all. I have not touched any of the brakes yet. What will help get it to not slide the front wheels.? It went 8.05 in the 1/8th mile. I have some wider tires I can install very easily.
As the guys mentioned you will not get full stall or very close to, but stronger
rear brakes help alot, Use ajustable perportioning valve or simply adjust if drums on rear.. This will help alot! just like the buick guys do to enable them to reach higher boost with out pushing. or install transbrake and have lots a fun.
Reply
Old Mar 27, 2008 | 10:10 AM
  #8  
thumper115's Avatar
Thread Starter
Junior Member
 
Joined: Jan 2008
Posts: 43
Likes: 0
From: Hayti, MO
Car: 1972 SS Nova, 1991 Camaro drag only
Engine: Stock 350, 355 w/12.5's
Transmission: 350 auto's
Axle/Gears: 3.55, 3.73
Re: Stall Speed?

Originally Posted by 87_TA
As the guys mentioned you will not get full stall or very close to, but stronger
rear brakes help alot, Use ajustable perportioning valve or simply adjust if drums on rear.. This will help alot! just like the buick guys do to enable them to reach higher boost with out pushing. or install transbrake and have lots a fun.

I installed the new rear brakes it did not help much, but it did go a 7.81 in the 1/8th. When this motor comes off the line it seem to be very flat till it hits the 3,000 rpm range or higher, then it just plants you to the seat. I believe if I change the front wheels to a wider tread it should hold better, I have a set on my 72 Nova we are change for this weekend and try it to see what happens.
Reply
Old Mar 27, 2008 | 01:31 PM
  #9  
F-BIRD'88's Avatar
Supreme Member
 
Joined: Sep 2001
Posts: 6,111
Likes: 53
From: Ontario, Canada
Car: 1988 Firebird S/E
Engine: 406Ci Vortec SBC
Transmission: TH-350/3500stall
Axle/Gears: 7.5" Auburn 4.10 Posi-Traction
Re: Stall Speed?

Originally Posted by thumper115
I installed the new rear brakes it did not help much, but it did go a 7.81 in the 1/8th. When this motor comes off the line it seem to be very flat till it hits the 3,000 rpm range or higher, then it just plants you to the seat. I believe if I change the front wheels to a wider tread it should hold better, I have a set on my 72 Nova we are change for this weekend and try it to see what happens.
You need to change your launch technique.
If you want to know what your converter stall is , watch the tach right when the car launches. (on slicks)
Don't try to load up the motor against the brakes at the starting line.
You only need to raise the motors rpm on the converter enough to get clean throttle response. usually 2000+/- rpm is good. Then rug it on the last yellow.
If you have a big long duration camshaft in the motor, you need to recurve the distributor to maximize the throttle response and launch torque. If you have more than 244@.050 cam duration, you can lock out the distributor timing. 34-36deg full time.
Once you do that and dial in the carbs accelerator pump shooters, the car will launch hard without trying to launch it as if it had a trans brake.
(The throttle response and low end torque will be much better)
Ideally you want the converter to stall to the engines peak torque point or 500rpm below that peak torque output point as the car leaves the line.
By loading up the converter against the brakes you are actually killing off some converter flash and torque at launch.
What cam are you using? what is the distributor spark advance curve?
Torque converters have a rpm range where they get the best performance downt he whole track. A 4500 stall needs a stiff rear gear to allow the car to rev at least 7000rpm thru the traps. 3.73's are not enough gear. If the converter stalls beyond the point of peak engine torque at launch, it is too loose.

Last edited by F-BIRD'88; Mar 27, 2008 at 01:38 PM.
Reply
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
Hotrodboba400
Firebirds for Sale
3
Dec 10, 2019 07:07 PM
rjcme
Tech / General Engine
0
Sep 5, 2015 01:23 PM
Hotrodboba400
Firebirds for Sale
0
Sep 2, 2015 07:28 PM
FLAP
Camaros Wanted
0
Sep 2, 2015 09:22 AM




All times are GMT -5. The time now is 11:18 PM.