Ok, so the owner of PI built me a "custom" stall for my Denali. It's supposed to stall at 3000rpm. I've put some miles on it over the last few days and decided to see what I could brake-stall to. 2300rpm. What's the deal? Anyone know why this would be? Stock I would hit 2000, which is WAY too low for my setup. I was really hoping it would hit 3000, at least. My boost would only see 4psi (it was 2psi stock at 2000rpm).

Any thoughts? It's too late to call PI right now......

 

Is the stall rating on converters the brake stall point or the flash point. My bro has a 03 SSS w/ headers/cam etc and he is running a TT3000. I know that he has his best results brake stalling it to 1600-1800 rpm. It brake stalls higher than that w/out moving, maybe to 2200-2300 rpm would be about the highest but he has not had good success launching it that high, of course, is isnt trying to build boost either...not yet anyway. After he punches it, the rpms flash up to at least 3k if not slightly higher and the truck shoots off. I dont know if this helps or not.

 

I am surprised that it wont stall a little higher on your truck since you are starting to build boost around those rpms. BTW, my brother is going to be running the sts kit w/the gt67, what rpm do you hit full boost at?

 

I dont think that the stall is rated at what it will brake stall to.

 

When I talked to the builder at PI, he said it should stall around that rpm so I had him build it. But 2300 isn't even close. To me it would be worthless to spend close to $1000 on a stall that gives me only 2300rpm, especially if the stocker shows 2000rpm and is supposedly a 1700rpm stall.

Beeftip - I don't know exactly what rpm I'm hitting full boost. I think it's around 4000rpm. It's up there. I'll have to check and see once I get this Stall issue squared away. I'm surprised your brother is finding better times launching at such low rpm. If he as an SS, he should stall as high as possible to get the most out of it since it's all-wheel-drive. No spin to worry about. Odd...

 

It just hits harder out of the hole when it flashes up from what we have tried. It is a noticable difference between 1800 and 2200 when launching. When it flashes up and catches it will plant you in the seat.

 

I can brake stall my tt3000 to about 2500rpm in my ss and I get the wheels spinning when I launch, it kicks ***.

 

Good reading below was it true stall or flsh stall that PI quoted you?


Converters are rated to stall within a certain rpm range. That’s not because the converter companies don’t know their product; it’s just that your individual engine characteristics and vehicle specs influence stall speed and make a precise number nearly impossible to predict. Even the term “stall speed” itself isn’t perfectly defined. Here are the three distinctions you’re likely to encounter.

True Stall: The rpm the engine cannot exceed when the driveline is locked. The most accurate way to determine true stall is by locking First gear and Reverse with a transbrake and observing engine rpm at wide open throttle (WOT).

Flash Stall: The rpm the engine “flashes” to when launched from rest at WOT. A converter will often briefly flash to a higher rpm than its true stall speed.

Brake Stall: The rpm the engine cannot exceed with the brakes locked and the driveshaft not spinning. Brake stall isn’t usually an accurate measuring tool since the engine often overpowers the wheels before the true stall speed is reached.

When a converter company quotes you a stall speed, verify whether it’s flash stall or true stall. Most converter companies quoted us flash stall figures. Many factors determine where the converter will flash stall once it’s installed in your car. Heavy cars with tall (numerically low) gears and large-diameter tires offer more resistance to forward motion, so the converter will stall at a higher rpm than it would in a light car with steep gears and short tires. The easier the motor can accelerate the vehicle, the lower the converter will need to stall to get the car moving.

Of course, the power and torque curves of your motor will have a huge effect on stall speed. Generally speaking, engines that produce more low-end torque will bump the stall speed to a higher rpm. Conversely, the same converter will stall to a lower rpm behind a less torquey, higher-winding engine. Converter companies often designate the former as “big-block” and the latter “small-block.” When you buy a typical converter that’s rated at 2,000-2,500-rpm stall, that rating is meant to span a variety of motors with different power curves. Scott Miller of TCI points out his company’s 12-inch Saturday Night Special converters typically stall at 1,600-1,800 rpm behind a 325-375 lb-ft “small-block” and up to 2,000 rpm behind a 400-450 lb-ft “big-block.” Sure, they’ll stall even higher behind a torquier motor, but they’re intended for mild, conservatively cammed motors.

Miller explains that any converter’s size limits the amount of torque it can safely handle. Although larger-diameter converters have bigger parts, that’s not always a good thing. Larger fins mean the fluid can exert more bending forces and result in failure. In stock form, bigger converters also allow more torque multiplication and lower potential stall speed, but the internals can handle only so much torque before parts start breaking. Reducing the diameter of the converter reduces its ability to multiply torque, puts less stress on the fins, and raises the stall speed, so small converters are generally better suited to peaky high-performance engines with higher-winding powerbands.

 

Nice! So 2500 is pretty close to my 2300. From what I understand, the more power you make, the higher the stall will be, all else being equal. I just always heard they would stall the same as what the "rating" was.

You must be pushing some serious power to spin all 4! I'm not even close, and that's with 470/520!

 

What were your mods again?