Being the broke dyck hilljack career test and tuner that I am, I'm curious about something...

Approximately how many HP does it take to move the stall of an 8" converter a solid 250 RPM's, up or down?

I've done some ET/Weight and ET/MPH calculations, just wondering if there is anyone who has this data.

goob- known good converter = hilljack engine dyno

This message has been edited. Last edited by: Goob,

100 HP GIVE OR TAKE.....

quote:

Originally posted by 329L:
100 HP GIVE OR TAKE.....

Damnit!! That's about what I came up with too.

New engine is a real disappointment so far.

65

100hp is 400rpm

quote:

Originally posted by Goob:

quote:

Originally posted by 329L:
100 HP GIVE OR TAKE.....

Damnit!! That's about what I came up with too.

New engine is a real disappointment so far.

Something else to think about. Sometimes you have to build a higher stall converter to utilize a combonation. I had a customer that had a 421 sbc with 23 degree heads that ran 5.90s. Converter would go 6200 and the engine made 710 hp. Put a set of 13 degree heads on same short block, engine made 840. We used same converter and it only stalled 5800 and only ran .05 faster than 23 degree engine. We built a new converter with less pump, and more stator, and the converter stalled 6700, and car picked up to mid 5.70s. Sometimes, a converter has to be changed to get the engine happy so that it will run.

Yeah, on paper this engine should have been about the same as everything else I've run in this car....so far a gear swap and a converter swap have done nothing.
It is what it is, I guess.
I'll wear it out and never speak of it again.

quote:

Originally posted by Goob:
Yeah, on paper this engine should have been about the same as everything else I've run in this car....so far a gear swap and a converter swap have done nothing.
It is what it is, I guess.
I'll wear it out and never speak of it again.

Is the cam possibly degreed in to the wrong spot?

quote:

Originally posted by 329L:

quote:

Originally posted by Goob:
Yeah, on paper this engine should have been about the same as everything else I've run in this car....so far a gear swap and a converter swap have done nothing.
It is what it is, I guess.
I'll wear it out and never speak of it again.

Is the cam possibly degreed in to the wrong spot?

I suppose it's possible, but only if the cam isn't actually what the card says.
Either way, there's not .3 ET and 4 MPH worth of wrong.
I'm just going to roll with it, if it continues to hold fluids inside and print ET slips.

quote:

Originally posted by Goob:

quote:

Originally posted by 329L:

quote:

Originally posted by Goob:
Yeah, on paper this engine should have been about the same as everything else I've run in this car....so far a gear swap and a converter swap have done nothing.
It is what it is, I guess.
I'll wear it out and never speak of it again.

Is the cam possibly degreed in to the wrong spot?

I suppose it's possible, but only if the cam isn't actually what the card says.
Either way, there's not .3 ET and 4 MPH worth of wrong.
I'm just going to roll with it, if it continues to hold fluids inside and print ET slips.

LOL...naw, cam degree aint going to make that much difference.

IMO torque numbers are what influences stall changes. More torque equals higher flash.

quote:

Originally posted by Footloose:
IMO torque numbers are what influences stall changes. More torque equals higher flash.

It's ALL torque, since HP is merely a theoretical figure derived from a Torque over Time calculation.
Everything changes at 5250 RPM's

Goob I have changed motors nothing very different but added a 1/4 stroker.same heads cam etc. and my stall speed picked up about 300 rpm. I put bigger headers on and will find out if I lose some torque. I hope your doing well.

quote:

Originally posted by 329L:

quote:

Originally posted by Goob:

quote:

Originally posted by 329L:
100 HP GIVE OR TAKE.....

Damnit!! That's about what I came up with too.

New engine is a real disappointment so far.

Something else to think about. Sometimes you have to build a higher stall converter to utilize a combonation. I had a customer that had a 421 sbc with 23 degree heads that ran 5.90s. Converter would go 6200 and the engine made 710 hp. Put a set of 13 degree heads on same short block, engine made 840. We used same converter and it only stalled 5800 and only ran .05 faster than 23 degree engine. We built a new converter with less pump, and more stator, and the converter stalled 6700, and car picked up to mid 5.70s. Sometimes, a converter has to be changed to get the engine happy so that it will run.

Impossible

Fantasy story

It's ALL torque, since HP is merely a theoretical figure derived from a Torque over Time calculation.
Everything changes at 5250 RPM's [/QUOTE]

Not exactly. I changed the combination in my 468 years ago, and the engine was 100 hp better. Car ran exactly the same. I figured more hp would actually make the converter better. What I found was the peak torque moved up pretty good, and the converter was way off. Picked up 4 tenths after it was loosened up.

quote:

Originally posted by Bob Deniker:

quote:

Originally posted by Goob:
It's ALL torque, since HP is merely a theoretical figure derived from a Torque over Time calculation.
Everything changes at 5250 RPM's

Not exactly. I changed the combination in my 468 years ago, and the engine was 100 hp better. Car ran exactly the same. I figured more hp would actually make the converter better. What I found was the peak torque moved up pretty good, and the converter was way off. Picked up 4 tenths after it was loosened up.

Your interpretation of how that happened changes if you apply the fundamental.

Torque = HP x 5252 / RPM

Goob is 100% correct

RPM and torque are measurable quantities of engine output.

100 hp gain is typically two and a half tenths to three tenths improvement in performance, on the track.

100 hp increase, increases observed stall by 400 rpm's

This message has been edited. Last edited by: Mike Rietow,

Another thing I'll add to help ya out is... If you move the peak torque up, it'll be higher at the point peak torque was previously.

The other fundamental of observed stall is K factor.

Using this equation you can determine stall beforehand of any given converter.

Observed stall divided by the square root of the torque input.

RPM = K x v/torque

quote:

Originally posted by Footloose:
Goob I have changed motors nothing very different but added a 1/4 stroker.same heads cam etc. and my stall speed picked up about 300 rpm. I put bigger headers on and will find out if I lose some torque. I hope your doing well.

Doing better than I deserve, probably. Hope you're doing well too.

Your change makes sense, stroke is torque.

quote:

Originally posted by Bob Deniker:
It's ALL torque, since HP is merely a theoretical figure derived from a Torque over Time calculation.
Everything changes at 5250 RPM's

Not exactly. I changed the combination in my 468 years ago, and the engine was 100 hp better. Car ran exactly the same. I figured more hp would actually make the converter better. What I found was the peak torque moved up pretty good, and the converter was way off. Picked up 4 tenths after it was loosened up.[/QUOTE]

Oh I agree, my car has always ET'd better than it should, combination is king.

I need to get Chad Speier in this discussion since I'm lacking good data on my new cylinder heads....

quote:

Originally posted by Mike Rietow:

quote:

Originally posted by 329L:

quote:

Originally posted by Goob:

quote:

Originally posted by 329L:
100 HP GIVE OR TAKE.....

Damnit!! That's about what I came up with too.

New engine is a real disappointment so far.

Something else to think about. Sometimes you have to build a higher stall converter to utilize a combonation. I had a customer that had a 421 sbc with 23 degree heads that ran 5.90s. Converter would go 6200 and the engine made 710 hp. Put a set of 13 degree heads on same short block, engine made 840. We used same converter and it only stalled 5800 and only ran .05 faster than 23 degree engine. We built a new converter with less pump, and more stator, and the converter stalled 6700, and car picked up to mid 5.70s. Sometimes, a converter has to be changed to get the engine happy so that it will run.

Impossible

Fantasy story

**CANT believe i actually clicked the hide post button to see what you said**

But, it is possible, and with the 3 different brand converters, and several different converters from those 3 companies each and every converter company said same thing, that the converter needed to be looser to allow the engine to get where it needed to run. You have to rememeber, it doesnt matter what them dynos say, if the engine cant accelerate it wont run right down the track. The particular engine i am talking about built awesome power on the dyno, but it didnt want to pull rpm on the dyno either. We went from a "B" pump and 41 degree stator to a B pump and a 35 degree stator which shouldnt have raised stall more than 200-300 rpm, but instead it picked up 700 rpm and was .1 faster and 4 mph. As a trans/converter guy, i can make your 30k engine look bad, and i can make your garage built engine look like a hero more than people realize.