I have a t bucket(1700 lbs) with a 400 sbc,3 dueces, ford 2.80 rear end, TH350 tranny.I want to install a stall converter & i have to replace the flywheel.Now heres the question what stall do i get, someone told me 1800-2200 & also can someone explain the theory behind the stall converter. does it lock up at 2200? or will it not move till 2200 is reached? how will it effect normal driving? Thanks JimV
2300 stall in my opinion,is the engine cammed? it will defineately feel different on the shifts.mine at times you can't tell when it's actually shifted.also it seems to me that my engine is revving more and idling different.
Jimv, a stall converter is what the name applies. It has built in slip up till a certain predetermined rpm, intended to act kinda like slippin' the clutch. In case with an engine that has a longer duration cam where it doesn't start making horsepower until a higher than stock range. It would bog with a stock rpm converter the higher stall speed allows it to build power and therefore leave better. The idea is to gear and select the correct stall speed to match the engine and driving style. (be honest about what you're intentions are with the combo) I am rambling and there are many others here with better understanding of this than me and hopefully they will pipe in. Brant
Saying that a car won't start moving until the rpm reaches the stall speed is a myth (BS). A higher stall convertor will not put AS MUCH power into the trans at lower rpm as the convertor is slipping more, but once you have reached the stall speed (all rated stalls are approximate-HP, Torque, car weight etc all play a factor in actual stall speed of a given convertor.) the convertor will not allow the engine to increase rpm if the trans can't allow the power out-such as holding the brakes, a transbrake etc... This means if you have a 2,200 rpm convertor, and you hold the brakes while giving the engine 'gas', the engine rpm will stop increasing at about 2,200rpm. It will not stall the motor. Normal 'stall' convertors will not acheive 100% lock up at any rpm, there is always some slip, usually 2-3% after going past stall speed. This is not really any diferent than your stock convertor. I really like the B&M 1800-2200 cheapy convertor for mild small block cars. It allows the rpm to rise alittle to help the car off the line but you don't give up any drivability as you would with a 3500 stall convertor. I have put them in quite a few cars, my wifes 54 chevy with a 327, th350, 3.36:1 rear runs well with one. I put one in my brothers 56 DOdge with a 360", 727, 3.50:1 and it made a noticable difference from the stock covertor I took out. I have done some for other guys too, never had someone say they didn't like it. Big block or high torque motors should use a beefier convertor though. I killed a cheapy with my 401" Buick a few years back. I think with the highway gears you have, you would benefit greatly with a mild convertor such as the 1800-2200. But keep in mind that the small block in the light car with highway gears, you will be on the low side of the rated stall speed. (compared to a heavy car with a big block etc...) As far as the difference in feel when the trans shifts, yes the higher stall convertor will soak up some of the harshness for sure. If you have a shift kit in the trans, the feel is still decent though. In my Buick, the 3500 stall convertor eats up any shift below the stall speed and takes a lot of the hit out at higher speeds. This is good in the way that it absorbs a lot of the shock and saves parts, haven't torn THIS rear out yet. Mild stall convertors are your friends... I think you'll thank yourself for the change.
With the 2:80 gear your running,you may not be happy with anything other then a stock type replacement convertor. Keep in mind a stock convertor, depending on application, may stall at approx. 1200-1800 rpm. Talk to most any trans parts/convertor rebuilder and have them recommend/explain what you will except from a given stall speed. just my .02
I think he will benefit from a small stall convertor, it will allow the engine to come up in rpm a little, this will help the high gearing he has. I don't think a high stall convertor (28-3500 or more) will be a good idea, it will never reach near 'lock-up' as the engine rpm at cruise speed will be much lower than the stall speed. Yes stock convertors can at times stall between 16-1800, but not usually with a light car and a small block. I could foresee a big block in a heavy car getting near that, but not a mild small block in a 1700 pund car.
Stock cam, I'd go with a stock converter. Bigger cam, maybe 1,800 - 2,200 stall. Really radical cam and you should consider taller gears and 3,000+. Wingnutz is right though....there's definitely a trade off with higher stall (more heat, more slip at normal driving speeds, and less mileage). -Lee Atomic Radio www.atomicpinup.com
I was looking at this one. http://store.summitracing.com/partdetail.asp?autofilter=1&part=BMM%2D20416&N=700+115&autoview=sku
Exactly what Wingnutz said. The basic rule of thumb if you're going to be raceing I.E 1,320 or 660 Ft is that the stall should be just below the RPM of max torque. Then after that it'll take some fine tuneing to figure out exactly what stall is right for your particular setup. To explain stall is basically to explain physics. its not as simple as the stall speed is when the converter locks up. There are a ton of variables. Vehicle weight, torque, applied torque, etc. If you're just looking for something that is a good all around converter for one that you drive and race occaisionally I would take a look at a something called a Saturday Night Special or a Street fighter if I recall B&M and TCI both make one with a name like that and as the name implies they atre for someone who drives a lot of off track miles and wants to have bragging rights. The stall speed over stock will only be slightly higher, in a lighter vehicle it might help you not spin the tires every time you leave a stop sign etc. There is another option if you own a GM vehicle just snag an 11 or 10" converter from a mid size or for a Vega/monza. They stall a couple a hundred above your standard big converter, they weigh less and they are cheap.
Newer style 'lock up' convertors use a clutch internal of the convdrtor to lockthe drive hub to the convertor driven housing. A lockup 'TCC' solenoid applies fluid to lock the clutch.
no such thing. The newer vehicles with lock-up (TCC) will lock up and not slip once you get up to speed, but every torque converter slips on take off until you reach lock up speed. This is usually 45-55 depending on make model tps% temperature, and a bunch of other stuff.
Not to beat this to death, but part of the education is to use the proper vocabulary...sorry, but that's true. There is no such thing as a "stall convertor" YES, people use the term, but it is incorrect. "Stall" is an attribute of all torque convertors, therefore you can have "high stall" (speed) torque convertors....but it's always a torque convertor. Basically, if the term "stall convertor" was accurate, then you would be describing something that converted stall. Exactly. And you don't have a flywheel. You have a flexplate. On to the theory behind a "high stall speed torque convertor". EVERY torque convertor manufacturer will tell you that stall speed is a variable IN APPLICATION. The manufacturer develops the product to a design stall speed, but the actual stall speed varies as a function of applied torque, which is a function of the weight of the vehicle, engine torque output, coefficient of friction, etc. In addition, even though you may have a torque convertor with a high stall speed, the lighter the vehicle the greater the reaction of that vehicle is going to be to the mechanical advantage represented by first gear...which means that the lighter the vehicle, the less resistance the brakes can provide to prevent the wheels from turning, and therefore you may never see the anticipated "advantage" of a higher stall speed. So...it's ALL variables, much like camshafts. This is one of those situations where you REALLY want to contact a torque convertor company and get their recommendations. Having said that, a higher stall speed tourque convertor would help with an engine that has a big cam, but only as a function of the (potential) higher idle rpm that the engine could "see".
In my experience, a light car likes a higher stall speed. My 28 A, with a stock converter, would always inch away if you didn't keep your foot frmly planted on the brakes. I replaced it with a 2200 B&M, and it would stay put at rough idle. That is why GM put smaller dia. into the lighter cars, is what my tranny guy told me anyway.
The popular vote seems to lean to the 1600-2200 range so i think i'll go with that. I have to replace the flywheel anyway so i'll have it apart. "dollabill" sorry for calling the flexplate a flywheel, but thats what its listed under in most parts catalogs.I'll stay after school & clean the blackboards!!lol JimV
to make the best decision let us know the cam, compression and tire dia. you are running and i would suggest changing that 2.80 to a 3.00 or 3.10. even higher numerically if you could take the freeway rpm. again what cam? your car would be a monster w/ 3.30 and still wouldnt run high fwy rpm.
If you happen to want a B&M Holeshot convertor, I have one here at the house that has about 10 minutes on it. Nothing wrong with it,, just didn't have enough "Stall" to get the truck moving. I had to go to a bigger stall convertor to get the hemi moving...
I went on B&M's website and asked them what would they recommend for my application. Told them the engine, cam, carb, type car, etc. They got back to me in a day or two with the recommended converter stall.
what rpm does your engine idle at? i think most stock converters have around a 900 rpm stall speed, except a vega.
I was told by B&M that they rate converters as a 3200lb car,3.55 gear,mild SBC and yes, even with that general info, it's still a SWAG ( Scientific Wild Ass Guess!) Gas mileage? yep! forget that shit! The wilder stall, the worse! My daily driver is SBC 383 mild engine, 700r4 with 10" "3500" converter, 4.11 gears, 2750 lbs and gets 10 in town and 11 on the road and runs 12.90 with mufflers and DOT tires. Point? Damn, I sure like that loose converter for smile action!
Rule of thumb is you look for a stall speed of 500-800 rpm less than peak torque curve on the moter which should be about the cruise rpm you want in high gear. Most off the shelf converters are built for approximatley 3200 lb car + or -. If the car is less weight it efffectivly lowers the rated stall speed also. If you have a lock up converter as in the newer overdrive units (700r4, ford Aod, etc) then the converter is locked mechanically by hydralic pressure on an enternal clutch this would alow the use of a higher than normal stall to take advantage of the torque multiplication that happens before lockup or stall happens. If you are using a standard 350th then a high stall probably wouldn't be too much of an advantage as the higher stall is also a measure of slippage which translates to heat so you would like it to lock up at a realistic driving rpm. Just my 2 cents worth and they may not be worth that much
OK second part to my question!! would i benefit more from leaving the stock converter & changing my rear ratio to 3.50?? What would everyone here do? I have to replace the flywheel( oops I mean "flexplate" LOL) thats why i figured i'd throw in the stall. There both about the same price & i can only afford one so "which one grasshopper??" JimV
What word would describe the condition of the motor at the point it won't increase in rpm due to the action of the converter?
If you are looking for a semantics argument, forget it-I don't have the patience for that. By stating the motor won't 'stall' I am obviously referring to the fact that the motor will not cease running-will not shut off-will not 'lose fire'-will not 'die'-need I go on? But thank you for that insight o-novakind67.
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