How much stall is too much stall for "long-distance" driving?

So, I graduate with my undergrad degree in a week, and I start work for the summer next week, so a torque converter may be on the wish list.

My question is exactly what the title says. The car is on the slow end of a street/strip car right now, with more strip-time than street this summer (my daily driver is either transit or a bicycle). The track is about a 1 1/2 hr. drive away, mostly on back country roads at 50 mph.

The car is the LeSabre listed in my signature. It has 3.42s/posi in the back with 235/75s right now, and a TH350 with a shift kit. I've got headers and a cam on the shelf right now, with the specs on the cam something like .450/.470 and 218/224 @ .050. These pieces may or may not go on the car this summer.

Thanks! :TU:

 

X 2 on your stock converter being fine and the switch pitch. What you have to look out for with a higher stall converter is heat build up. Say you have a 3500 stall converter and you drive around in a gear that causes you to be driving at 2000 rpms you are going to have excessive heat build up. You would most likely have more heat build up problems with city driving than you would highway. IMHO

Bob H.

 

wouldnt a 200-4r be better for him

 

Sure, if he's got an extra 2 grand laying around. I'd love a good 200-R4 too, but my wallet says no.

Don't mean to hijack, but anybody got a stall recommendation for a '71 LeSabre (4300+ lbs), 455 w/ TA 212 cam, 3.08 gears, 28" tires? Mostly street/strip, occasional towing.

 

I don't think there would be any problem but extra heat, so get a trans temp gauge installed and run a big trans cooler with its own small fan.

 

You guys aren't answering his question. He is planning a cam swap.

I'd say anything more than 2800 would be a pain. you'll want a big cooler aswell.

 

I guess that's the decision I have to make. Indeed, a Switch-Pitch would be ideal, but I think that's a bit more than I can afford at the moment. I know the stock converter would be just fine with this cam, but, at the same time, I'd like to optimize stall speed for the track -- i.e. as much stall as possible that I can get away with on the street, because, at the moment, this is primarily more strip than street. And when I say "street," I mean that most of the driving that this car does is highway driving.

A built 200-4R would be great, but to build it up enough to withstand land-yacht launches is quite an investment.

Thanks for the input, fellas! :TU: I think it'd be nice if I could "borrow" a converter for a week and just see how it feels.

 

Ok, to answer your question you need to ask yourself what you want the car to do for you.

A stall converter is great if your racing around and REALLY dont care about gas milage or all the damn engine noise. Since you havnt had one in the past you need to find a buddy with one and test drive it.

The stall converter is basically like pushing in the clutch until the stall speed hits.... for example if its a 2500 stall you wont move an inch until 2500rpm!

With a stall converter you should always try to drive ABOVE the stall speed (which insnt very hard considering you dont move until it grabs) to avoid exsessive wear caused by slipping the converter. Because the converter slips under the stall speed it will obviously produce more heat as well which calls for a very large trans cooler.

The stall speed is always matched to the cams specs in your engine. Typically the stall speed is around 200-300rpm above your cams starting power range and its used as a tuning device enabling the engine to reach its rpm range quicker for better straight line performance. For example if you have a cam with an rpm range of 1200-5500 you will want a stall speed of 1400 or so.

Just so you know the 200-4r is a great trans and i just got done building mine at the transmission shop i work at. Sadly It doesnt come without a pirce tag though, mine is a race prepped trans which is necessary for mild to high horsepower v8s. I'm running a 2300 stall converter in it and with all the parts bought at my shops discounted prices im at a grand total of $1068. Thats just parts and not counting labor to build the trans myself and install it.

My advice... Stick with a VERY low stall speed if you want a stall converter. Otherwise stick with the stock one...its already in the car and working just fine!

 

This is completely wrong. Simple way to explain it in layman's terms, stall speed is the RPM where the converter "couples up" and stops becoming a multiplier of torque. It will still transfer power before the stall speed is reached. If you have a decent quality converter, you can still get "creep" when you take your foot off the brake leaving a traffic light even with a higher stall speed. If you are really working in a trans shop and think a car doesn't move until the converter's stall speed is reached you should look into a career change or at least get educated before spreading completely wrong information.

 

Great article, Larry - thanks for posting it.

I'm still curious, though...

* At what point would you recommend a higher-stall-than-stock converter, particularly in a heavy car?

* What about possible future cam upgrades - how big a jump in cam size before another converter is needed?

I fully realize that there aren't any 'magic' answers, but any general guidelines or 'rules of thumb' would be helpful.

Thanks,

 

Question:
I go to the trans. shop & ask for a stock TC for my '71 350/TH350.
Engine recently rebuilt back to stock specs., including the cam. Trans. rebuilt about 4 years ago, or 4000 miles ago, works as new.
He brings me a TC & tells me this is the right one.

What stall speed is it?

 

Steve, there's know way to know exactly until you try it. The stall will depend on how much torque the engine provides.

The well established companies have done so much r&d that theycan specify a particular internal design and diameter once they have all the detals from your engine and car combo. Even then, the converter may have to go back once or twice for the ultimate "tweak". Not uncommon for dedicated race cars where every 1/2 tenth needs to be eeked out.

Devon

 

I would say a quality 2200 stall would probably help out, BUT that is alot of money for probably not a tremendous amount of gain. $500 (at least for a good one) + $250 in labor for a shop to swap your converter. uzzled:

 

Devon & Larry....Thank You.
Looks like the TC mystery requires more study. Don't know too much about them.
Didn't know too much about a Q-Jet either until I rebuilt a few & studied the internals. Still pretty green but have a basic understanding on how they work.

 

the way it was explain to me on the switch pitch was that old ladies keep hearing noises when they were stopped. it keep the creeping down and the
brakes from talking. jim