Stock converter rework

[SIZEMOREMK]

Thought I'd share what went on when I tried to order a converter from PTC in Florence Alabama. I believe PTC is the converter MO's usually recommends, and the shop working on my car also highly recommended PTC.

I have personally used PTC for a few converters over the years, and with my previous lower level performance builds, they have always steered me towards working over a stock converter over their higher stall aftermarket units.

I have never had an issue with any of their rebuilds and I think they've done 4 for me altogether plus this one they just built. A friend had the same experience in his recent LS swapped 78 corvette project.

I figured this time at the (hopefully) 450+ level with a centri, I figured it was time to go ahead and order a sho-nuff high-stall converter.

I called to ask about the single and triple disc units, and was told they actually use the same triple disc clutch components that Precision Industries used, but they do a few things differently in their converters.

I was also told that there was not really all that much difference in the longevity of the single and triple disc units if they are locked up at WOT. So basically don't lock the converter at WOT. I know some guys do lock the converter at the strip, but I really don't race, so for me this was a non-issue.

So I told them I wanted them to build me one of their single disk units in 3200-3500 stall range to handle 500 HP or so with a centri blower and he talked me out of their unit and told me to send mine for rework.

They said they would loosen it up about 500 RPM, furnace braze the fins, turn down the stator, replace the clutch, and I believe they swap a plastic thrust washer for a torrington bearing also. This service costs $175 plus shipping.

He said that this was a really strong factory unit and that I wouldn't need to worry about balooning and that I should be able to rev as far as I wanted with it.

He said their units would have a little better torque mulitplication ratio, but claimed that if I went higher on the stall for a daily driver they would generate more heat, probably significantly reduce fuel mileage, and probably not care much for the extra slack in the converter i normal driving.

I forgot to ask about the weight difference, as I understand rotating mass makes a difference.

I know several of the guys here love their higher end converters, and some claim they can't tell much difference with a 3500 stall when properly tuned, but I just wanted to throw this out there so guys know there are other options.

I was ready to spend the $700+ or so on a new converter like everybody's doing, but when the converter guys recommended this, I had to go with it.

I look forward to giving a review of the converter when the car gets put back together.

[eric jones]

I look forward to hearing about the results. I didn't know that rebuilding the stock unit was a viable option.

[MOTOWN]

I look forward to hearing about the results. I didn't know that rebuilding the stock unit was a viable option.

Honestly its not, compared to a Circle D , or precision converter if your going to spend that much money do it right the first time.

[jwibbity]

BOC does the same thing. They send a new stock MM converter out to Circle D to have it rebuilt and beefed up, it was around 450 when I bought mine, and you can have it built to whatever stall you want.

I;m currently running it with a 3K stall.

[SIZEMOREMK]

Honestly its not, compared to a Circle D , or precision converter if your going to spend that much money do it right the first time.

Are you saying you don't think the rebuilt unit would be of good quality, or are you saying there would not be enough performance gain?

[Jeronimojc]

Great post. I wish I had known a few months ago. $175 vs $1,000 is a big difference for me. Please do let us know how the converter performs.


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[chief455]

Honestly its not, compared to a Circle D , or precision converter if your going to spend that much money do it right the first time.
I talked to Circle D about restalling one of their 11.5" 2800 rpm convertors, they said you can only go so far to effectivly flash/stall with that diameter unit.
I wanted ~3500 stall, they suggested getting a 10" diameter unit.
hope your reworked stock unit does what you want it to.
If you don't want 'flash' or foot brake stall, but rather mild slippage over bone stock, you might be happy.
I wouldn't expect such a convertor to improve 60' or 1/4 mile E.T by half a second like a higher stall convertor could.
Lidio is a fan of stock sized convertors, his cars go fast - so who knows....
Me, I love the hit when my little convertor flashes right into peak torque and burns my tires off, rather than a tight convertor lugging unil rpm reaches above 3000rpm.

[MOTOWN]

Are you saying you don't think the rebuilt unit would be of good quality, or are you saying there would not be enough performance gain?

Absolutely go with a Circle D or Precision converter from the start, as chief said you only have so much to work with reworking a converter especially a stock one which was never designed to be a high stall type converter.

I have a Circle D 3K tripple disc and let me tell you it is by far the best converter your money can buy! and yes you will totally forget its in the car, they are that good.

[chief455]

So I told them I wanted them to build me one of their single disk units in 3200-3500 stall range to handle 500 HP or so with a centri blower and he talked me out of their unit and told me to send mine for rework.
good range choice
They said they would loosen it up about 500 RPM, furnace braze the fins, turn down the stator, replace the clutch, and I believe they swap a plastic thrust washer for a torrington bearing also. This service costs $175 plus shipping.
not even 2800 stall speed
He said their units would have a little better torque mulitplication ratio, THE STR IS WHAT MAKES A CONVERTOR PERFORM but claimed that if I went higher on the stall for a daily driver they would generate more heat, TRUE probably significantly reduce fuel mileage, NOT TRUE and probably not care much for the extra slack in the converter i normal driving. PERSONAL PREFERENCE

I know several of the guys here love their higher end converters, and some claim they can't tell much difference with a 3500 stall when properly tuned, TRUE but I just wanted to throw this out there so guys know there are other options.

I look forward to giving a review of the converter when the car gets put back together.
I hope you are happy, but they talked you out of a 3200-3500 convertor, but saved you money. Have you ever driven a street car with a 3000-3500 convertor? just curious...

[sailsmen]

............ Have you ever driven a street car with a 3000-3500 convertor? just curious...

I have for 160K miles. It's all in the tune.;)

[SIZEMOREMK]

No sir, I have not driven a car with 3000-3500 stall, I really wish I had as to have made a more informed decision.

You may have seen my other thread where I have an unplanned engine rebuild and such going on, as well as a tranny rebuild. I wasn't about to rebuild the tranny and put the old converter with 140K miles on the TC clutch back in it. So a converter rebuild was pretty much required at a minimum.

I think this worked out for the best for me at this time, because the bill is getting rough with all this work :bigcry:

Right after I was talked out of the 10" converter, I took some other more expensive engine related options that came available a couple of days later.

I also believe that 3500 stall would be less useful without some drag radials or slicks on widened wheels, which would then almost require diff and axle upgrades.



As far as "not knowing its there" for normal driving, I assume that has more to do with the tune, and less to do with the converter itself? Is that correct?

I have been wondering what it is they do in the tune to hide it? I image that they must lock it up in 1st and 2nd under a certain percentage of WOT???

I hope I am satisfied with it, if not there is always another round of mods when the wife gets over this round in 5-10 years, LOL.

[chief455]

No sir, I have not driven a car with 3000-3500 stall, I really wish I had as to have made a more informed decision.
I NEVER KNEW HOW GREAT A STALL CONVERTOR IS AS A MOD UNTIL I HAD THE RIGHT ONE IN MY CAR. SINCE THEN, 30 YEARS AGO, CONVERTOR IS MY FIRST BOLT ON, EVEN TO AN OTHERWISE STOCK CAR.

Right after I was talked out of the 10" converter, I took some other more expensive engine related options that came available a couple of days later. YOUR ENGINE ITSELF MAY WARRANT THE STALL CONVERTOR TO GET THE MOST OF IT

I also believe that 3500 stall would be less useful without some drag radials or slicks on widened wheels, which would then almost require diff and axle upgrades. SEMI CORRECT. IF YOU DRIVE LIKE A CIVILIAN 80% AND HAVE FUN 20% ON THE STREET, YOU WON'T CARE ABOUT STICKY TIRES. DRAG RADIALS MAKE GREAT DAILY TIRES, IF YOU KEEP TO SUNNY DAYS, NOT MUCH RAIN, NO SNOW. THEY HELP HOLD THE LAUNCH OF A HIGH STALL CONVERTOR. SLICKS WILL YIELD BEST RESULTS OF A TRUE MATCHED STALL CONVERTOR, IF YOU'RE INTO TRACK TIMES. THIS IS WHEN AXLES AND TRANNY UPGRADES WOULD BE REQUIRED.

As far as "not knowing its there" for normal driving, I assume that has more to do with the tune, and less to do with the converter itself? Is that correct?
HOPEFULLY, YOU SURE WILL KNOW IT'S THERE! WHAT WE MEAN IS, WHEN YOU CRUISE THROUGH TRAFFIC AT PART THROTTLE, STALL CONVERTORS JUST SLIP ALONG GRACEFULLY, SHIFTS ARE SOFTER THAN WITH A TIGHTER, STOCK CONVERTOR, AND HIGHWAY DRIVING, THE CONVERTOR WILL LOCK UP (IF EQUIPPED) OR BE ENGAGED ENOUGH TO NOT HAVE NOTICABLE SLIP = YOU WILL FORGET IT'S THERE.
UNTIL YOU MASH THE GAS ANYWHERE UNDER THE RATED STALL RPM - THE ENGINE RPM WILL 'FLASH' TO AROUND THE HIGH STALL SPEED, AND TORQUE MULTIPLICATION WILL HIT THE TIRES HARDER THAN ANY STOCK OR TWEAKED STOCK CONVERTOR WILL = WEEEEE!! ALSO, UPSHIFTS WILL NOW BE CRISP AND FIRM, NOT HARSH OR BANG LIKE WITH A TIGHT CONVERTOR. OFF THROTTLE DOWNSHIFTS ARE MILD, CONSISTENT AND ACTUALLY SOME DISENGAGE AS YOU APPROACH STOPPING / IDLE SPEED. THEY ARE QUITE MILD MANNERED UNDER LESS THEN FULL THROTTLE CONDITIONS.
I have been wondering what it is they do in the tune to hide it? I image that they must lock it up in 1st and 2nd under a certain percentage of WOT???
THIS I DO NOT KNOW. LOCK UP IS ONLY IN 3RD AND OVERDRIVE. LOCKING UP USES A SMALL CLUTCH IN THE CONVERTOR, WHICH IS NOT THAT STRONG ON LOWER COST CONVERTORS, AND TAKES ALL STALL SPEED AWAY. IT IS FOR FINAL DRIVE ONLY. IT IS THERE FOR ECONOMY AND REDUCING CRUISE RPM.
I HAVE RUN DOZENS OF STALL CONVERTORS WITHOUT COMPUTER CONTROL WITH RESULTS STATED ABOVE.
IN MY COMPUTER SHIFTED TRANS CARS, I MOSTLY TWEAK UPSHIFT POINTS, OVERDRIVE ENGAGEMENT, LOCK UP RPM/MPH SETTINGS, THROTTLE POSITION VS SPEED VS MAP SETTINGS ETC. - IT IS NOT MUCH MORE THAN TUNING WITH A STOCK CONVERTOR, JUST DIFFERENT SETTINGS. YOU ARE NOT TRYING TO 'HIDE' IT, JUST MAKE THE CAR SHIFT RIGHT WITH IT, SINCE IT IS DIFFERENT THAN STOCK.
I hope I am satisfied with it, if not there is always another round of mods when the wife gets over this round in 5-10 years, LOL.
I think you'll be fine, and you can swap in a higher stall convertor later and tweak the shift schedule.