Torque Converter? Where am I at? What is compromised?

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Kent mosby

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This is the status of my car as it is right now.

1973 Plymouth Scamp
RB 512ci, 440 source stroker kit with lightweight crankshaft, forged pistons, 10.83 CR. Trick Flow 240 heads, 440 source aluminum rockers 1.5RR, Trick flow single plane intake. Holley super sniper EFI, hyperspark ignition, coil and distributor. TTI 2 inch headers. Hughes 3000 stall converter. 727 transmission with transgo tf2 valve body mods. B&M Quicksilver shifter. Gear vendors overdrive to 8 3/4 rear end with 3.91 gears, braced in back. SS leaf springs. Competition engineering race shocks. Pypes exhaust 3" into 2.5 inch. RacePro mufflers. Mickey Thompson ET street SS Drag radials 255/60-15 27.3 inch) but going to 275/60-15 28.2 inch diameter. Current cam specs 244/252 @ .050”, 282/290 adv, .516”/.537” lift(1.5:1 rocker), 112 sep, .016”/.018” lash, Solid lifter from Oregon Cams.

Both Ken Heard at Oregon cams and Steve Magnolo at Hughes converters recommended a 3000 stall converter. Ken said "3000+" Steve said 3000 for street/strip and 3500 if mostly strip.

So I have the hughes 24-30HD https://www.jegs.com/i/Hughes-Performance/512/24-30HD/10002/-1

My question is more of what does having the 3000 stall converter give to performance on the street versus the 3500 stall for the strip? What, if any benefit would the 3500 stall do? Are we talking 2 tenths of a second in the quarter or 2 seconds in the quarter? How does the 3000 stall make it better on the street? What would you notice?

FWIW, My intended use is mostly street and next year hopefully the track reopens in Spokane. then about 8-10 trips to the track. I am not competing in any class. Just Friday test and tune.

I have tried to "Google" the differences but I have come up short in my search for the differences. The answers I get are use this stall for this application and that stall for that application.
 
With a shelf converter, probably minimal difference in that between the two. Between a shelf and a custom converter, night and day. I'd send it and not sweat it and think about a PTC or Precision of New Hampton converter down the road. Somewhere that has a custom order sheet or a guy on the phone asking a lot of questions.
 
IMHO, if you are going to be doing 99% street driving, and your race track is for fun (test and tune) I would go for a more stock converter like in the 1800 to 2000 range. Otherwise you will always be slipping the clutch so to speak while you are doing 99% of your driving.

5000 miles per year street driving
10 trips to strip
20 passes per trip
0.25 miles per pass
50 total miles on the strip
1% strip driving
 
Dana67Dart said:
IMHO, if you are going to be doing 99% street driving, and your race track is for fun (test and tune) I would go for a more stock converter like in the 1800 to 2000 range. Otherwise you will always be slipping the clutch so to speak while you are doing 99% of your driving.

5000 miles per year street driving
10 trips to strip
20 passes per trip
0.25 miles per pass
50 total miles on the strip
1% strip driving
Click to expand...
I don't agree. A "Stock" type converter would be a huge handicap for that engine.
 
forphorty said:
I don't agree. A "Stock" type converter would be a huge handicap for that engine
Click to expand...
For racing I agree but for running around town I bet the tires will be easily spun with lower stall converter.

Just my 2 cents
 
Converters can be a complex subject. Modern converter technology is nothing like it was even ten years ago. You can get a converter that will flash to 5000 RPM but be tight enough to drive to work every single day. Of course, you don't need that. But the fact is, you could and it would be tight enough that it'd still get decent mileage, not have that "slipping clutch" feel and not generate an excess amount of heat.

I agree that a 3000 converter is pretty mild there. That's not far off from what a stock Chrysler high stall converter was. They generally flashed to 2500 or so.....one might go to 3000 behind your 512, since converter flash is directly related to an engine's torque.

If that was mine, I'd have a custom converter made that'd flash to 3800-4200. They can make it plenty tight at cruise RPM so as not to have excess slippage and yet, when you hem it up to launch, flash to that 3800-4200 stall speed and be a real beast on launch.
 
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I run a PTC 9.5" that flashes to 3800-4000 rpm in my 505" '68 B-bod..drives great when cruising the kids to school or putting around town...but mash the gas and it's brutal, especially on a 3-2 downshift from a 35-40mph cruise. It's magnificent.
And, I might be in left field here so no offense is intended...but Hughes coverters are lame IMO, at least the ones I've used.
Give one of the reputed converter shops a call and tell them all your specs and desires, you won't regret it.
 
And try this:
Get cruising in 3rd, but not so slow that it downshifts, then quickly mash the throttle while watching the tach. The needle will instantly jump to a certain RPM and then slowly climb with engine speed. That point that it jumps to is your (approximate) 'flash' stall which is more relevant to your individual combo than advertised stall ratings.
 
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Kent mosby said:
This is the status of my car as it is right now.

1973 Plymouth Scamp
RB 512ci, 440 source stroker kit with lightweight crankshaft, forged pistons, 10.83 CR. Trick Flow 240 heads, 440 source aluminum rockers 1.5RR, Trick flow single plane intake. Holley super sniper EFI, hyperspark ignition, coil and distributor. TTI 2 inch headers. Hughes 3000 stall converter. 727 transmission with transgo tf2 valve body mods. B&M Quicksilver shifter. Gear vendors overdrive to 8 3/4 rear end with 3.91 gears, braced in back. SS leaf springs. Competition engineering race shocks. Pypes exhaust 3" into 2.5 inch. RacePro mufflers. Mickey Thompson ET street SS Drag radials 255/60-15 27.3 inch) but going to 275/60-15 28.2 inch diameter. Current cam specs 244/252 @ .050”, 282/290 adv, .516”/.537” lift(1.5:1 rocker), 112 sep, .016”/.018” lash, Solid lifter from Oregon Cams.

Both Ken Heard at Oregon cams and Steve Magnolo at Hughes converters recommended a 3000 stall converter. Ken said "3000+" Steve said 3000 for street/strip and 3500 if mostly strip.

So I have the hughes 24-30HD Hughes Performance 24-30HD: Heavy Duty Pro-Street Torque Converter for Mopar A727/TF8 & A518/46/47RH | JEGS

My question is more of what does having the 3000 stall converter give to performance on the street versus the 3500 stall for the strip? What, if any benefit would the 3500 stall do? Are we talking 2 tenths of a second in the quarter or 2 seconds in the quarter? How does the 3000 stall make it better on the street? What would you notice?

FWIW, My intended use is mostly street and next year hopefully the track reopens in Spokane. then about 8-10 trips to the track. I am not competing in any class. Just Friday test and tune.

I have tried to "Google" the differences but I have come up short in my search for the differences. The answers I get are use this stall for this application and that stall for that application.
Click to expand...

let me say that my set up is close to urs, a little hotter, and hasnt performed to my expectations yet , have made a few changes tho.
I have the hughs 3500 convertor in mine and have always felt like its too loose for the street, and have wondered if its slipping too much on the strip ------
and when hitting passing gear , it gets way hairy and cant look at the tach , fish tailing , while leaving hard at the same time , (treaded slicks)
 
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4 tenths in the quarter is what I have picked up switching from a 3000 stahl Hughes to 5800 ptc.. I don’t think you would see a gain at all just switching a 3500 Hughes. But if you get a custom converter built you will be very happy and see that 3-4 tenths in the quarter….
 
i'm no authority but a good friend put a 2600 stall converter behind his 400 stroked to 508 in a 72 Duster with 30" tall tires and 3.55 gears. Although they were not wide slicks he could break the tires loose easily at 50 plus mph! Your engine in a scamp without a drag purpose suspension might not be a great fit?
 
A TA “tight” 10” would be a pretty good compromise converter for the OP’s combo.

I’d expect it to have a true flash stall of 3500-3700 behind his 512.

Next step up would be something like a tight custom 9.5” from PTC or UCC, but frankly....... those might end up being a little loose for the OP’s [email protected] cam.
 
I am more confused than before I began this thread. Many say that I need a looser TC (higher Stall), yet @bob mCcarty says his may be too loose for the street. My car does not get squirelly when I punch it from 35-40 mph. It might chirp a bit, barely.

Back to my original post. What I meant to ask is.. What street manners do I give up if I were to get a more race prepped converter. As @RustyRatRod and @beanhead mentioned 3800-4000 flash or so. I am not chasing 3-4 tenths to lose all street driveability. What if any driveability would I lose by going to 3800-4000? If going from 3000 to 5800 gives 3-4 tenths, I would not change. I just learned that a tight converter acts tighter at lower rpms but looser during hard acceleration. I guess I nee to check my Flash stall as beanhead mentioned.

Finally, do I understand this correctly that the reason for higher stall in race conditions are so that you can get the engine up to higher torque range for starting a drag race before releasing the clutch, transbrake or brake? I don't have a transbrake but I do have a linelock. Never used it for anything but burnouts. Being inexperienced as a racer, I just start my race from Idle. Does that information change any recommendations? Still learning...
 
JMO... The converter is the single most important component in the driveline of an auto car. Period.

I've had 3500 hughes converters work really well (Brian from IMM mag build 408 in his duster, went 1.43 60') and was solid.

If you have the 3K item and want to run what you have, do it. A custom piece as Rusty mentions is a good choice and will cost some $. Seen plenty of cars with custom tight cruise, 4000+ flash converters have lower highway rpms than stock and off the shelf 3000-3500 units. I would not put a stock level converter in your car with your intended use.
 
Kent mosby said:
I am more confused than before I began this thread. Many say that I need a looser TC (higher Stall), yet @bob mCcarty says his may be too loose for the street. My car does not get squirelly when I punch it from 35-40 mph. It might chirp a bit, barely.

Back to my original post. What I meant to ask is.. What street manners do I give up if I were to get a more race prepped converter. As @RustyRatRod and @beanhead mentioned 3800-4000 flash or so. I am not chasing 3-4 tenths to lose all street driveability. What if any driveability would I lose by going to 3800-4000? If going from 3000 to 5800 gives 3-4 tenths, I would not change. I just learned that a tight converter acts tighter at lower rpms but looser during hard acceleration. I guess I nee to check my Flash stall as beanhead mentioned.

Finally, do I understand this correctly that the reason for higher stall in race conditions are so that you can get the engine up to higher torque range for starting a drag race before releasing the clutch, transbrake or brake? I don't have a transbrake but I do have a linelock. Never used it for anything but burnouts. Being inexperienced as a racer, I just start my race from Idle. Does that information change any recommendations? Still learning...
Click to expand...

All I can tell you is you're confusing "loose" with "flash". Re-read my last post. You can get a converter that will flash to 5000 RPM and will NOT be loose one iota on the street. I know that's not what you need, I'm simply making a comparison.

Today's converter technology does not mean a "loose" converter at all. You need to call a reputable converter company and have a long talk. Tell them every single detail about your car, what's in the engine, ALL of it, what gear you're running, the as is curb weight, EVERYTHING. Then they will give you their best recommendation. Let them know you want a converter that'll perform the best with your combination but still be tight for street use.

Precision of New Hampton is an excellent place to start. They manufacture their own converters and make a fine product at competitive prices. I dealt with a lot when I worked for a local transmission shop. Good people. Then after you talk to them, if you're still not convinced, get a second opinion. PTC, Dynamic, Coan...those are all top notch converter companies. I bet they will all be within 500 RPM of each other's recommendation and it will likely match what I said......unless you tell them you want to drive the car like granny on the way to church on Sunday.
 
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RustyRatRod said:
All I can tell you is you're confusing "loose" with "flash". Re-read my last post. You can get a converter that will flash to 5000 RPM and will NOT be loose one iota on the street. I know that's not what you need, I'm simply making a comparison.

Today's converter technology does not mean a "loose" converter at all. You need to call a reputable converter company and have a long talk. Tell them every single detail about your car, what's in the engine, ALL of it, what gear you're running, the as is curb weight, EVERYTHING. Then they will give you their best recommendation. Let them know you want a converter that'll perform the best with your combination but still be tight for street use.

Precision of New Hampton is an excellent place to start. They manufacture their own converters and make a fine product at competitive prices. I dealt with a lot when I worked for a local transmission shop. Good people. Then after you talk to them, if you're still not convinced, get a second opinion. PTC, Dynamic, Coan...those are all top notch converter companies. I bet they will all be within 500 RPM of each other's recommendation and it will likely match what I said......unless you tell them you want to drive the car like granny on the way to church on Sunday.
Click to expand...

Sorry, I must be lousy at expressing myself. I do understand that they can make good converters that have a higher stall but still be streetable. The logic goes like this. If I have a car that drives well on the street, the engine, transmission etc. What advantage do I gain by changing to a "better" TQ than what I have? Similarly, What do I give up, if anything, or nothing, by getting a better torque converter?

The cost is not a factor. 600-700$ is not going to sway my decision. Pulling the trans to do the job is more difficult to justify. If the benefit is not worth the effort to do so......
 
Kent mosby said:
Sorry, I must be lousy at expressing myself. I do understand that they can make good converters that have a higher stall but still be streetable. The logic goes like this. If I have a car that drives well on the street, the engine, transmission etc. What advantage do I gain by changing to a "better" TQ than what I have? Similarly, What do I give up, if anything, or nothing, by getting a better torque converter?

The cost is not a factor. 600-700$ is not going to sway my decision. Pulling the trans to do the job is more difficult to justify. If the benefit is not worth the effort to do so......
Click to expand...

Kent, I guess it all depends on the converter you have now. If we were local, I could drive it and tell you if it was worth spending the money or not. Where about are you in the tater state?
 
Kent mosby said:
Sorry, I must be lousy at expressing myself. I do understand that they can make good converters that have a higher stall but still be streetable. The logic goes like this. If I have a car that drives well on the street, the engine, transmission etc. What advantage do I gain by changing to a "better" TQ than what I have? Similarly, What do I give up, if anything, or nothing, by getting a better torque converter?

The cost is not a factor. 600-700$ is not going to sway my decision. Pulling the trans to do the job is more difficult to justify. If the benefit is not worth the effort to do so......
Click to expand...
Personally I would not change it. 3000 converter is perfect on the street. Just know there is room for improvement that would improve your 60 ft time, and it will equate to a 4 tenths gain in the quarter, if traction and suspension support it. If you want to get everything out of it and you have money to spend, have dynamic converter build you a converter. You won’t lose drive ability on the street… they work well.
 
RustyRatRod said:
Kent, I guess it all depends on the converter you have now. If we were local, I could drive it and tell you if it was worth spending the money or not. Where about are you in the tater state?
Click to expand...
Post Falls, Up north. 25 miles from Spokane, 8 miles from Coeur d'Alene
 
QKFSH67 said:
Personally I would not change it. 3000 converter is perfect on the street. Just know there is room for improvement that would improve your 60 ft time, and it will equate to a 4 tenths gain in the quarter, if traction and suspension support it. If you want to get everything out of it and you have money to spend, have dynamic converter build you a converter. You won’t lose drive ability on the street… they work well.
Click to expand...

I sorta agree....but there are some really crappy converters out there. If he has one of those, he could gain a lot even on the street. He DID ask.
 
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