Testing Converter Stall

[Just a Six?]

Question about testing stall with a trans brake?
I know that ASSuming the brakes are in Good working order & set snug for track purposes with S-10 cylinders etc. that by holding the foot brake & raising RPM, when the car starts to break loose that is roughly your converter stall. Lets just say you get 3500 rpm.

Now by using a stage right trans brake is there a similar way to do the testing of converter stall? If the brake is engaged would the engine sort of level out at 3500 rpm or is there even any way to do a similar type of test with the T Brake??

Also since I'm asking, if using the Emergency Brake will the converter start to level at 3500 like the I ASSume the T brake will or would it be more like the footbrake & try to push thru??

I want to retest the Pats 10" converter as many ways as possible before I consider swapping in my 9-11 for the season. Thanks!  

[Steve Wood]

there are a number of ways to test stall.  Dusty Bradford looks at the rpm when the boost gauge is at zero...in other words, the transition between vacuum and boost.  Given the variation between various converters and how they behave, this may be the best way to compare different converters to one and another.

I do it the old way as you describe.

When using a tranny brake, you do as you said.  Mash the pedal down and see where the rpm stops and the boost at that point.

Be very careful to do this quickly and not try to hold it for a minute while you think about it.  This heats the tranny fluid like mad and will burn the tranny up if prolonged.  In the old days, we have seen guys that knew it took the buick guys awhile to build boost so they staged slowly and left the buick wound up against the converter so it would get hot.

Doing it like you would against the foot brake is fine...bring it up, and let off when the rpm stops.

Using the E Brake applies more pressure to the drums than the foot brake does...this is even more true on the cars with vacuum brake conversions that put less pressure out of the m/c.

Of course, the rear brakes need to be adjusted properly-as they should be anyway.

The danger is that the e brake mechanism using the backing plate as its leverage point and can, and will, twist the backing plate which screws things up.  I am not coordinated enuf to use it in a race so I don't have to worry about that

[Just a Six?]

Since I have Vacuum brakes & no factory prop valve & now no adjustable prop valve the rears will hold more boost than DR's can handle quite easily. This is NOT Ideal for Wet Weather!!!   :bigeyes;
15lbs is no problem on the line so I have never even tried my T Brake?? Altho, Paul (Quicktoy) made me a custom detent plate for the column shifter so I can Slam It from 1-D very hard at lauch. Now I just want to re confirm where exactly my converter stalls. I know the 3400 9-11 is more efficient but I am only allowed 11.50 & I can do that at 21 lbs running pig rich with the 67 H cover. The testing is more just to satify my curiosity as the 3800 is more fun just going stoplight to stoplight for pretty much instant spool.  
If the 3400 will give me more MPH (which it should) I'll get Dan to throw it in just to compare. I just hope my back is healed more by BPG or I might just be watching anyways! Doing my Physio so I should be a lot better by then.  ;

[gordyzx9r]

I thought for sure Steve would have honed in on the S10 brakes...

[Just a Six?]

I thought for sure Steve would have honed in on the S10 brakes...

I did say Not for Wet Weather!! If so then drive Slow!!  :bigeyes;

[gordyzx9r]

I thought for sure Steve would have honed in on the S10 brakes...

I did say Not for Wet Weather!! If so then drive Slow!!

[Steve Wood]

I noticed them, but, if you want to kill yourself, it is your business

[Just a Six?]

I have upgraded the fronts with vacuum system, Hawk pads, braided lines & slotted rotors BUT I would Never tell anyone else to follow my madness. You have to always be aware that you are at a disadvantage & drive accordingly! I drive like an 80 year old man!

Altho, one Sunny Dry morning on the 401 Hiway that has 5 lanes plus shoulders there was Nobody in front or behind me so I did some testing without locking the brakes like a panic stop but I was being very aggressive with my testing so they were close to locking up. I hit them for 50 mph then 60 then 75 & the car nosed down in front & stopped straight which was a pleasant surprise to me.
I will probably reinstall the adjustable prop vave again since the lines etc are all ready to go but the car stopped better than I would have thought it would from hiway speeds.
Also, my vehicles see very limited road time. Even my Denali may get 10K a year at max with going to Ohio & back included. One tank of gas lasts me 2 months on average.

Again I am Not Suggesting anyone else try this mod!!  Just get a T Brake & hold all the boost you want safely. :rolleyes:

[daveismissing]

... You have to always be aware that you are at a disadvantage & drive accordingly! I drive like an 80 year old man!

Finally acting your age!
 

[Just a Six?]

... You have to always be aware that you are at a disadvantage & drive accordingly! I drive like an 80 year old man!

Finally acting your age!
 

My family always wondered when this day would come!  :finga:

[gordyzx9r]

I have an SSBC brake system up front, S10 brakes in the rear, all new SS brake lines, and a fairly new Powermaster.  But I forgot to replace the stupid OEM proportioning valve with one of the newer non-rusting ones.

[motorhead]

David,

I can speak to the "wear" that a Trans Brake puts on fluid. I am pretty certain that my builder put DEX IV (lots of friction modifiers) in my TH400 2 years ago and with only a few test sessions and a few tries at the track the fluid came out very dark just the other day.

I switched it for a 10:3 ratio mix of standard viscosity John Deere HyGard tranny fluid and Type-F (mostly for colour), respectively.

The idea here is that the new fluid will reduce slippage over conventional DEX-style fluids. This is applicable in both the application of the clutches on the shift and in the overall stall rating of the torque converter. I had a horrid time with CS% last season and I am trying this out before I get into swapping/modifying converters.

The other benefit is that the JD fluid is damn near indestructible by comparison to conventional transmission fluids (think industrial vs. commercial). The other option is synthetic compressor oil from AMSOIL.

I have yet to footbrake or transbrake the car to see if it lowered the stall, but most of the research I have done shows a 300rpm decrease in stall speed once JD fluid is added.

[Just a Six?]

David,

I can speak to the "wear" that a Trans Brake puts on fluid. I am pretty certain that my builder put DEX IV (lots of friction modifiers) in my TH400 2 years ago and with only a few test sessions and a few tries at the track the fluid came out very dark just the other day.

I switched it for a 10:3 ratio mix of standard viscosity John Deere HyGard tranny fluid and Type-F (mostly for colour), respectively.

The idea here is that the new fluid will reduce slippage over conventional DEX-style fluids. This is applicable in both the application of the clutches on the shift and in the overall stall rating of the torque converter. I had a horrid time with CS% last season and I am trying this out before I get into swapping/modifying converters.

The other benefit is that the JD fluid is damn near indestructible by comparison to conventional transmission fluids (think industrial vs. commercial). The other option is synthetic compressor oil from AMSOIL.

I have yet to footbrake or transbrake the car to see if it lowered the stall, but most of the research I have done shows a 300rpm decrease in stall speed once JD fluid is added.

I have now read about the John Deere fluid a few times with positive results. I'll keep the info for when I get some real testing done so I have a fair comparison if I decide to use it.
Thanks Mike!  

[daveismissing]

I suppose you don't use that in a tranny under warranty.

You guys shoulds switch avatars, after all- which one is married to Natasha?

[Just a Six?]

I suppose you don't use that in a tranny under warranty.

You guys shoulds switch avatars, after all- which one is married to Natasha?

Little Boris Badenoff had the Original Natasha Darling.
She was the beauty & the brains behind catching Stupid Moose & Squirrel!