Home | Register | Login | Contact Us

 
Auto Math
Classifieds
Forum
Gallery
Games
Garage
Tech Articles
Utilites
 
FAQFAQ    SearchSearch    RegisterRegister    Log inLog in    Log in to check your private messagesLog in to check your private messages    Forum Subscriptions1/4 Mile Table 

What stall speed is the best! some reading before you decide
Goto page 1, 2  Next
 
Post new topic   Reply to topic    SMOKEmUP.com Forum Index -> Driveline / Suspension
View previous topic :: View next topic  
Author Message
af2
Member


Joined: 01 Sep 2003
Posts: 5578
Location: grassvalley, ca
71842.50 points


1933 Willys Coupe

PostPosted: Thu Jun 21, 2007 6:34 pm    Post subject: What stall speed is the best! some reading before you decide Reply with quote

Everyone leaves off the stall and that is totally wrong! What is a converter?
A multiplier! Why would you leave there?! I have looked into this myself and came to the conclusion I was wrong!
Think about a 4500 stall? You have a stall to get the motor into it's range. Before take off! So lets say you stall it to the flash. What is going on? It leaves at 1:1? Yes! You leave at 2000 and what happens? You have an instant reduction! Hence stall speed! Now comes into play is reaction time? You're 60 is best leaving at 2000 but the reaction is better at 3000? So what is better? The ET is way better at 3000 so what gives?
I am there and went with a way bigger stall to compensate we'll see!
Back to top
View user's profile Send private message
wagon train
Member


Joined: 07 Jun 2007
Posts: 258
Location: Orange City, FL
7307.16 points


1983 Mercury Capri

PostPosted: Thu Jun 21, 2007 7:38 pm    Post subject: Reply with quote

Stall speed is different for every engine. The more torque an engine will make with the same convertor it will stall higher.

The engine is making more torque at that rpm,so the fuel is better suspended,so therefore making better power down track.

Also the carb could be atomizing the fuel better at the rpm with better signal.

Not sure if I answered your question,but thats what I now from my experience

_________________
FORD POWER RULES DEATH TO ALL CHEVYS.

"BAKER"
10/5/50-11/7/06

"She doesn't seem to be breathing right,it might be the jets."-The Mechanic
Back to top
View user's profile Send private message
af2
Member


Joined: 01 Sep 2003
Posts: 5578
Location: grassvalley, ca
71842.50 points


1933 Willys Coupe

PostPosted: Thu Jun 21, 2007 7:44 pm    Post subject: Reply with quote

wagon train wrote:
Stall speed is different for every engine. The more torque an engine will make with the same convertor it will stall higher.

The engine is making more torque at that rpm,so the fuel is better suspended,so therefore making better power down track.

Also the carb could be atomizing the fuel better at the rpm with better signal.

Not sure if I answered your question,but thats what I now from my experience


You are correct about the different combo's. Like I said almost everyone leaves at the stall and I feel that is wrong!
Back to top
View user's profile Send private message
Paul P
Member


Joined: 15 Aug 2002
Posts: 2449
Location: Townsend, Mass.
83052.36 points


1971 Chevrolet Chevelle

PostPosted: Fri Jun 22, 2007 2:23 pm    Post subject: Reply with quote

Almost everyone you are right. That means almost everyone is wrong too. I have a 4000 stall converter but leaving on the brake at about 3200-3500 yields the best launch. This is with a converter recommended for the street for the combo I have. For a all out drag setup it would be a 5000 unit. then it would leave really hard.....
Back to top
View user's profile Send private message
wagon train
Member


Joined: 07 Jun 2007
Posts: 258
Location: Orange City, FL
7307.16 points


1983 Mercury Capri

PostPosted: Fri Jun 22, 2007 5:22 pm    Post subject: Reply with quote

I was told by Marv at A-1 trans that you want the absolute stall speed to be right on peak torque after the shift.So when you shift it lays on peak for a second(just a term)then start locking up from there.That should net you the best results.
_________________
FORD POWER RULES DEATH TO ALL CHEVYS.

"BAKER"
10/5/50-11/7/06

"She doesn't seem to be breathing right,it might be the jets."-The Mechanic
Back to top
View user's profile Send private message
af2
Member


Joined: 01 Sep 2003
Posts: 5578
Location: grassvalley, ca
71842.50 points


1933 Willys Coupe

PostPosted: Fri Jun 22, 2007 5:30 pm    Post subject: Reply with quote

Thanks for the replies. An ATI article made me think again on launching at the converter flash ( stall ). They stated the super stockers run the Quickest at 1800 stall but they don't say what the actual stall/flash is?
Paul answered that with what his best is. There is a local racer that has 2 cars running 2 different classes that launches off the flash and has ruined converters since he started? One runs the 7.60 index and the other 8.60. A friend runs the 8.60 car. I can't figure out a way to tell them they are killing the converters in the Pitt's by braking to flash and releasing the brake letting off the throttle at the same time (I am sure everyone that races has witnessed that ). That IMO doesnt give any cool down and you spin the sprag to who knows what rpm. And it doesn't impress me knowing what they are doing to the converter.

I started this post to inform and get input on my thought vs yours.
Back to top
View user's profile Send private message
af2
Member


Joined: 01 Sep 2003
Posts: 5578
Location: grassvalley, ca
71842.50 points


1933 Willys Coupe

PostPosted: Fri Jun 22, 2007 5:39 pm    Post subject: Reply with quote

wagon train wrote:
I was told by Marv at A-1 trans that you want the absolute stall speed to be right on peak torque after the shift.So when you shift it lays on peak for a second(just a term)then start locking up from there.That should net you the best results.


I understand that completely.
What do you launch at is my question?

Most everyone I have heard launches at peak stall. I think that is wrong!
Back to top
View user's profile Send private message
af2
Member


Joined: 01 Sep 2003
Posts: 5578
Location: grassvalley, ca
71842.50 points


1933 Willys Coupe

PostPosted: Fri Jun 22, 2007 6:22 pm    Post subject: Reply with quote

The topic I totally blew it on and will try again with the correct wording! Rolling Eyes
Back to top
View user's profile Send private message
af2
Member


Joined: 01 Sep 2003
Posts: 5578
Location: grassvalley, ca
71842.50 points


1933 Willys Coupe

PostPosted: Fri Jun 22, 2007 6:36 pm    Post subject: What do you feel is the correct launch given a stall of? Reply with quote

I screwed up the post in my other!
PaulP is with me on this one. Shocked
If you have a 6000 stall what would you leave at?
Same with any other stalls.

Would you leave at 6000 or 3500?
OR do you leave at 6000?
ATI has an article that says their guys leave at 1800 and go to stall on the launch. I feel it is conservative but true to let the converter do it's job. After seeing 2 cars a person I know eat converters for the last few years leaving at the rated stall I wondered if launching the car at flash killed them? Also the pit launch?

Anyway that is what my first post was. Rolling Eyes
Back to top
View user's profile Send private message
10sec.et
Member


Joined: 29 Mar 2006
Posts: 3483
Location: Houston,Texas
347040.52 points


1969 Oldsmobile Cutlass

PostPosted: Fri Jun 22, 2007 8:26 pm    Post subject: Reply with quote

af2 wrote:
wagon train wrote:
I was told by Marv at A-1 trans that you want the absolute stall speed to be right on peak torque after the shift.So when you shift it lays on peak for a second(just a term)then start locking up from there.That should net you the best results.


I understand that completely.
What do you launch at is my question?

Most everyone I have heard launches at peak stall. I think that is wrong!


i was told years ago that you should ALWAYS launch at LESS than peak stall. seems to me that if you launch at peak, youre defeating the purpose of having a stall because youre starting to lag the motor.

_________________
af2 wrote:
It seems we can look at our magical Balls and come up with a fix?

Back to top
View user's profile Send private message
af2
Member


Joined: 01 Sep 2003
Posts: 5578
Location: grassvalley, ca
71842.50 points


1933 Willys Coupe

PostPosted: Fri Jun 22, 2007 8:28 pm    Post subject: Re: What do you feel is the correct launch given a stall of? Reply with quote

af2 wrote:
I screwed up the post in my other!
PaulP is with me on this one. Shocked
If you have a 6000 stall what would you leave at?
Same with any other stalls.

Would you leave at 6000 or 3500?
OR do you leave at 6000?
ATI has an article that says their guys leave at 1800 and go to stall on the launch. I feel it is conservative but true to let the converter do it's job. After seeing 2 cars a person I know eat converters for the last few years leaving at the rated stall I wondered if launching the car at flash killed them? Also the pit launch?

Anyway that is what my first post was. Rolling Eyes


I thought I started another thread? ???I give???????
Back to top
View user's profile Send private message
William Jones
Member


Joined: 30 Jan 2006
Posts: 826
Location: Lake city, FL
28640.90 points


1971 Ford Mustang

PostPosted: Fri Jun 22, 2007 10:14 pm    Post subject: Reply with quote

I have 4000 stall converters and leave at 2800 on the footbrake and 3000 on the transbrake that is what gives me the best results and I haven't burnt up a converter yet.
_________________
Take the horse out off the barn and let her RUN BABY RUN!!!!!

92 LX 454ci Clevor 9.24@142.53 N/A
71 Mach1 454ci Clevor 10.16@134 N/A 3850lbs race weight "Lost in fire"
03 Cobra Bone stock 12.42
68 Falcon 363ci 10.55@126 N/A
95 GT 363ci 11.08@118 N/A
Back to top
View user's profile Send private message
Big Dave
Moderator


Joined: 04 Dec 2005
Posts: 2662
Location: Tampa Florida
120504.72 points



PostPosted: Fri Jun 22, 2007 10:54 pm    Post subject: Reply with quote

If you leave before stall speed you get added torque multiplication provided by the slipping converter. However if your trap RPM and shift points are not above the flash point then you are leaving some ponies at the gate and will be slipping all the way down the track. It will be advantageous to know peak torque, peak horse power (or at least RPM of shift point which you program in with line pressure and valve body) and the true flash point of the converter with your current tune.

Sounds like a question for a transmission shop that has a chassis dyno.

Big Dave


Last edited by Big Dave on Fri Jun 22, 2007 11:41 pm; edited 1 time in total
Back to top
View user's profile Send private message
Knarley Darley
Member


Joined: 22 Apr 2004
Posts: 1247

540238.26 points



PostPosted: Fri Jun 22, 2007 11:26 pm    Post subject: Reply with quote

I basically have a 500" prostock engine in my 67 camaro and my old engine combo would stall to about 7000 on the wood(limiter turned off) The new combo stalls to 8000 with the same converter. I leave between 5700 to 6600 depending on what the track will hold. The interesting thing is that when leaving at full stall with the old combo, the engine rpm would actually drop as the car rolled out and then start to rev past the original stall rpm about 80 feet out or so. Once I figured out that limiting the rpm on the line actually lets the rpm build as soon as the trans brake releases the car picked up almost .5 of a second in the quarter and started doing huge wheelies as well, instead of picking up the wheels on the initial release and then dropping them like a rock on the full stall launches. If I tried to leave at full stall(8000 rpm) with this engine it would do a quarter mile burnout! LOL
Back to top
View user's profile Send private message
af2
Member


Joined: 01 Sep 2003
Posts: 5578
Location: grassvalley, ca
71842.50 points


1933 Willys Coupe

PostPosted: Sat Jun 23, 2007 9:59 am    Post subject: Reply with quote

Knarley Darley wrote:
The interesting thing is that when leaving at full stall with the old combo, the engine rpm would actually drop as the car rolled out and then start to rev past the original stall rpm about 80 feet out or so. Once I figured out that limiting the rpm on the line actually lets the rpm build as soon as the trans brake releases the car picked up almost .5 of a second in the quarter and started doing huge wheelies as well, instead of picking up the wheels on the initial release and then dropping them like a rock on the full stall launches.


That is exacly what my car did with the old converter and what I needed to know on the new one!
Thanks guys!
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic    SMOKEmUP.com Forum Index -> Driveline / Suspension All times are GMT - 5 Hours
Goto page 1, 2  Next
Page 1 of 2

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum
Home | Contact Us | Automath | Cam Files | Dyno Search | Forum | Garage | Picture Gallery | Reaction Timer

Copyright 1997-2018 SMOKEmUP.com All rights reserved.
Advertising Info     Disclaimer     Privacy Policy