Thank you all so much for the information. I’ll get the gears changed and then look at the converter. PTC said they would loosen it at no charge if I decide it needed it.

quote:

Originally posted by Fatboy81:
Thank you all so much for the information. I’ll get the gears changed and then look at the converter. PTC said they would loosen it at no charge if I decide it needed it.

They're good like that, we just got this one back from them. It's an obsolete converter core now unavailable, originally out of an Australian Ford. We had the stall configured for around 1150hp to run the new DXP class at SGMP. This is a rad core I was told to not throw away by a guy at Transmission Specialties probably 15- 16 years ago. This thing can be tailored for power anywhere from 850hp to 1500hp and it's a 9" core. Glad I listened.

Good luck, keep results posted/updated.

quote:

Originally posted by Mike Rietow:

quote:

Originally posted by markemark:

quote:

Originally posted by DOTracer:
Be prepared to loosen the converter after putting more gear in as it will naturally want to tighten up due to less load.

I agree with what DOTracer wrote.

The only thing that can change stall is power, not in theory but in fact.

I disagree with you and here’s an example in the pic.

In the #0019 Acquisition this 3 speed transmission had 2.48 / 1.48 planatarys and the engine had a rpm of 6115 rpm @ 0.65 after launch ( Black Line).

One week later, in the #0024 Acquisition this 3 speed transmission now had 2.10 / 1.40 planatarys and the engine had a rpm of 6289 rpm @ 0.65 after launch ( Green Line).

Exact same engine and convertor, with the Corrected Altitude of both runs within 200’ of each other and very similar weather conditions.

With a 4.40 rear gear, the SLR (starting line ratio) in #0019 was 10.91. In the #0024 run, the SLR was reduced to 9.24 and the engine rpm increased by 174 rpm.

Works the same way changing the diff gears

This is a 6,000 stall converter, which probably goes 6200 when you deck it on the TB no chip, Don't let that fool you this is a 6,000 converter. The reason the engine is tugged down at .065 with the 2.48 low, is what allows the OP to to make a change from a 4.11 to a 4.56-4.88 according to engine rpm limits, the converter becomes more efficient. The more efficient the converter, the more it tugs on the engine. The only factor which determines stall is power. It's not an opinion, it's a fact.

So weight isn’t a factor in stall?

SMDH...

quote:

Originally posted by DOTracer:
So weight isn’t a factor in stall?

SMDH...

I understand what you're saying but if you're taking stall, power is the only constant determining stall.

I could say be prepared to loosen the converter because with more gear, the car will have more wheel speed resulting in less load. This would be an example of the same thing your saying. I wouldn't say that though because that's putting the cart before the horse. It is a fundamental though I get what you're saying, but it's a bridge to cross when you get there. Right now what we're working with is observed stall 5,500 on the transmission brake. Hell it may hook better with more gear and flash stall higher, I've seen that too.

Here's an example of what I'm talking about. First pass on a converter a friend had in his attic for ten years he wanted me to try. I call PTC to find out what it was and Kenny tells me try it, it's a pro tree converter. Well that tells me right there it'll snatch the taste out of your mouth off the trans brake. This thing stalls 6250 same as all my spragless converters, this has an active stator Borg Waner sprag. I turn the leave rpm down for this thing thinking I don't wanna end up on the bumper. Long story short it sounded like the windshield broke when it left and I'm thinking this thing is rolling out pretty decent, get out about half way through second and I'm thinking Judas Priest is thing thing gonna make it to the eighth mile engine screaming 300-400 rpm higher than normal. Converter only flash stalled 6050 because it blitzed the tire at the hit. This is an example of a converter if I put some more gear in it would ride out pretty good but I'd have to lower the leave chip even further to keep it off the bumper. Good converter acted just like PTC said it would only a couple two three hundredths slower than my spragless at the stripe with the early numbers equal if not a hair better. Not anything I'd run bracket racing though.

https://youtu.be/I8QWEaqeFRw

quote:

Originally posted by DOTracer:
So weight isn’t a factor in stall?

SMDH...

Weight, Gear, tire, horsepower all play a part in the stall. Even if the air is much better stall will be higher because you make more power. I agree horsepower may be the largest factor but certainly not the only thing.

quote:

Originally posted by Curly1:

quote:

Originally posted by DOTracer:
So weight isn’t a factor in stall?

SMDH...

Weight, Gear, tire, horsepower all play a part in the stall. Even if the air is much better stall will be higher because you make more power. I agree horsepower may be the largest factor but certainly not the only thing.

I can't address that claim without specific examples. I can say I'm sure we can both agree the only factor that will effect the stall positively of any given torque converter in a car sitting on the starting line, on the trans brake wide open throttle, no high chip at stall, waiting on the tree to come on, would be to shut the car off and install another engine with more power.

Once at stall wide open throttle on trans brake, if the rpm dips when the transbrake is released would be an example of over efficiency above stall.

Same scenario, If the rpm flashes would be an example of converter inefficiency above stall.