Aftermarket torque converters and max engine RPM

[Logizyme]

I often see people with aftermarket converters going on and on about stall speed, but with our cars I see another large advantage a smaller torque converter can allow, maximum engine RPM.

According to Jerry(the J in Jmod) The 12inch converter used in 4R7XX equipped trucks, and base model panthers is only good to 5400rpm before the converter begins to distort and failure can ensue, and that the 11.25 converter used in mustangs, and performance panthers(including Marauders) is good to 6500rpm.

The 03-04 Mach1 manual trans engine redline is 7000RPM while the Mach1 auto and Marauder is 6050RPM(or whatever - close enough). Peak power ratings are unchanged because peak power occurs at 6000RPM.

The way I see it when our auto shifts at 6050 RPM its dropping down into to 3300RPM during the 1-2, and 3900 during the 2-3. Then we have to climb our way back up to 5000RPM before we really get into our powerband.

We're leaving power our engine is capable of and potential speed behind. Could we rev our engines to the full 7000RPM that the Mach1 engine is capable of and we could remain in the powerband longer. 1-2 shift would be at 3800 and 2-3 at 4500, getting us back into the power band sooner.

Given the nature of the physics it should be safe to assume that a smaller high stall converter would also be capable of increased RPM.

Extremely modified 4.6 based 4v's have been built that are completely stable at 11,000rpm, a properly modified one could easily exceed the 7000rpm of the Mach1 manual.

Anyway, has anyone taken advantage of this trait of aftermarket smaller torque converters?

Am I wrong?

[fastblackmerc]

I'm using a 9.5" 3600 stall from PI.

http://www.converter.com/stallion.htm

[burt ragio]

Circle track 3000

[TooManyFords]

I run my motor to 7800 and have as small converter that stalls to 5500. It is fun.

[chief455]

stall convertor is my favorite mod to any automatic trans car.
mostly to get into the engines power band in a 'flash', but also to allow the top end rpm a bit of slippage. While less efficient, it is more fun, and to your point, will allow high rpm to occur quicker, and possibly higher rpm than a larger diameter convertor.
10" 3500 stall in my street car = :)

[Logizyme]

I'm using a 9.5" 3600 stall from PI.


Circle track 3000


10" 3500 stall in my street car = :)

Are you taking advantage of the ability and tuning your cars to shift at higher RPM's?

If so what RPM are you shifting at? (Tach only goes to 7krpm what happens after that LOL)

[chief455]

Are you taking advantage of the ability and tuning your cars to shift at higher RPM's?

If so what RPM are you shifting at? (Tach only goes to 7krpm what happens after that LOL)
safe for stock 85k used engine = 5800 shift point, 6200 rev limit
the real street fun is part throttle shift extension, at higher mph
use this 50 times more than WOT shifting, in a street car.

[Logizyme]

I would not hesitate for a moment to rev my stock 100kmi engine to 7k rpm - its the TC that's stopping me from rev'ing mine that far.

Stock tune shifts higher than 5800.

[chief455]

I would not hesitate for a moment to rev my stock 100kmi engine to 7k rpm - its the TC that's stopping me from rev'ing mine that far.

Stock tune shifts higher than 5800.
go for it!
I feel their is no reason to rev that high - peak torque already passed, and peak hp may be at 6X00, but I'm not racing anything = why push the limits. I'm supercharged = all the fun happened by ~6 grand.
next engine, built for boost, within the camshaft designed rpm range I'll rev more.;)
mine will go to 7k, just not doing it. it revs quickly as well, very snappy = lighter, smaller diameter mass on the back of the crank.

[99SVT]

Mine shifts at 7000 1-2, 6800 2-3, the Rev limit is set to 7200 to allow a bit of tire spin at the top of 1st with street tires. 6800 shift point puts it right close to peak torque going into 3rd.
Ported trilogy, aluminator, 2800 stall 9.5" convertor.

[chief455]

Mine shifts at 7000 1-2, 6800 2-3, the Rev limit is set to 7200 to allow a bit of tire spin at the top of 1st with street tires. 6800 shift point puts it right close to peak torque going into 3rd.
Ported trilogy, aluminator, 2800 stall 9.5" convertor.
NICE!:beer:

[Zombiesoldier]

what is the stock stall rating on a factory convertor?

[clmrt]

22-24 I think.

What did I win?

[Logizyme]

The ford rating for a torque converter stall is actually a range.

But to compare the factory 11.25" to an aftermarket converter, stall is 2400.

[nh muscle]

Pi 2600 stall 100 octane tune!

[Bradley G]

Circle D 10" 3600- 3800 stall
Tame & terrible best of both worlds!

[chief455]

Circle D 10" 3600- 3800 stall
Tame & terrible best of both worlds!
I think ~3600 10" is the ****nit for the rpm range of thee engines, stock included :)

[Bradley G]

All the advice I got prior to stalling the car that range was that was too high.
I listened to my tuner Lonnie Doll and ordered the piece directly from him.
I couldn't have been any happier with the way it drove!
I think ~3600 10" is the ****nit for the rpm range of thee engines, stock included :)

[Logizyme]

Pi 2600 stall 100 octane tune!


Circle D 10" 3600- 3800 stall
Tame & terrible best of both worlds!

Are you taking advantage of the ability and tuning your cars to shift at higher RPM's?

If so what RPM are you shifting at?

[Jeronimojc]

Good thread. Could we get more opinions? Also, what converters, RPM shift points, and max RPM are the supercharged guys set up at?

[Bradley G]

It's been so long since I've driven it I forget.
Hopefully soon I can report back.

[fastblackmerc]

Good thread. Could we get more opinions? Also, what converters, RPM shift points, and max RPM are the supercharged guys set up at?

I'd find someone local to dyno tune the car..........

[chief455]

Are you taking advantage of the ability and tuning your cars to shift at higher RPM's?

If so what RPM are you shifting at?
yes, tuning with the stall is required

Good thread. Could we get more opinions? Also, what converters, RPM shift points, and max RPM are the supercharged guys set up at?
I'm not experienced enough to suggest, but mine shifts right above 6000rpm by the tach. Mo's set my shift schedule, and tweaked it several times to my liking.
I prefer extended shift points, even during part throttle. Also, the down shift settings help you love the car more.

[Jeronimojc]

I'd find someone local to dyno tune the car..........

I'll definitely work with my local tuner and have the car dyno tuned. I hope to do this while I get it tuned for the supercharger.

I have been considering shifting from 1-2 at around 6500 and from 2-3 at around 6200 and a 3000 RPM stall. However, I am a bit concerned I'll lose traction as I have street tires and I think I'll be close to 600RWHP. Some here have stated a high RPM stall isn't a problem for drive-ability if it is handled properly in the tune. I don't quiet understand how that works though. Thoughts?

Any other S/C guys out there care to share?

[BigM460]

The car should be tuned with the converter locked, so...........

[chief455]

The car should be tuned with the converter locked, so...........
Engine parameters and WOT readings on dyno = convertor locked.
trans schedule should be based on driving the car.
Many tuners have a base trans schedule that would be decent. Tuning the trans can be very much based on personal preferences, and don't waste time tuning that until you get the stall in.
3500 stall, street = dreamy :banana:

think you'll lose traction near 600rwhp and street tires?
Stock or a 3000 stall convertor, you know it. ;)

You need to be aware of you main goal = street OR strip.
Your tuner could spend days and days getting your street tune just right.
Then if you want to try and 'soften' the tire hit through the tune, well that just defeats the purpose of the stall convertor. Use slicks or drag radials when you go to the strip.
my 1 penny.

[Jeronimojc]

I hear you. Wish I could do it all at once. The goal is good street driving and some fun every so often at the track.


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[jwibbity]

I hear you. Wish I could do it all at once. The goal is good street driving and some fun every so often at the track.


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why not get two tunes one for everyday driving and one for the strip, especially since you said you wont be going to the track that often..

[Jeronimojc]

Will definitely do that. I still don't know (understand) if and how a high RPM stall converter can be tamed in the tune for dd. I may just end up picking a stall RPM in the lower end (2800 to 3000).

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[BigM460]

Will definitely do that. I still don't know (understand) if and how a high RPM stall can be tamed in the tune for dd.


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Have you ever had a car with a stall in it? It will be the same. But once locked up all is good for dd. I had Jeff set mine up for no lockup, but in OD. So it acts more like a 5 speed trans. Mine under light throttle, normal driving, 1-2 is at 20 mph, 2-3 at about 30pmh, OD/4 at 40 then converter will lock. Only time it's annoying is if pulling a grade at low speed, like 35mph.

[Jeronimojc]

It is starting to make sense. Thanks for explaining. I'll do some more reading on this.


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[chief455]

I hear you. Wish I could do it all at once. The goal is good street driving and some fun every so often at the track.


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my advice = tune your car for this.

why not get two tunes one for everyday driving and one for the strip, especially since you said you wont be going to the track that often..
I think two tunes for transmission schedule will wise, but getting there will take some time.
I have had my trans tweaked 10 times to get my favorite street tune. The first tune was fine for most people, but as BigM460 says...

Have you ever had a car with a stall in it? It will be the same. But once locked up all is good for dd. I had Jeff set mine up for no lockup, but in OD. So it acts more like a 5 speed trans. Mine under light throttle, normal driving, 1-2 is at 20 mph, 2-3 at about 30pmh, OD/4 at 40 then converter will lock. Only time it's annoying is if pulling a grade at low speed, like 35mph.
I had these set points and raised them, including automatic down shifting.
I have my OD shift at 60mph and convertor lock up set 15mph after OD, so like a five speed. This may seem high, but I drive country roads where OD is rarely needed, so only set for highway use.
It also eliminated 'stacked shifts' where it shifts OD and lock up too close together.
I got rid of that pulling a grade at slow speed by auto downshifting at 40mph - it took a lot of driving under many conditions, then trying tweaked tunes.
To do that again, for a race tune, would be mental. I'll just go to the track and see what she does. Remember your goal.

[Jeronimojc]

I've got much to learn. I figured the street tune would take some work and the race tune would be easy (just a fun thing). I'll see what my tuner says, but it makes sense to concentrate on the street tune and go from there.


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[fastblackmerc]

Call Precision Industries for information.

[Jeronimojc]

Call Precision Industries for information.

Yeah, I've been working with them on this. We picked a 2800 to 3000 RPM stall converter. I also took into consideration Fordnut's advice.

[Jeronimojc]

My apologies for having derailed this thread. The OP brought up a good subject. Can we continue to get opinions?


Are you taking advantage of the ability and tuning your cars to shift at higher RPM's?

If so what RPM are you shifting at? (Tach only goes to 7krpm what happens after that LOL)



Good thread. Could we get more opinions? Also, what converters, RPM shift points, and max RPM are the supercharged guys set up at?