What is the stock "stall speed" on my 69 GS 350 (350 trans) converter? Man this thing feels like it's locked @ idle! I would like to go with a "Street Stall". Something where you don't have to "stand" on the breaks to keep the car from moving when stopped and in gear. The only mod my car has is a shift kit. That is something else that burns my wife's ass! It shifts pretty firm! I would hope a mild converter would lesson the shift BANG under moderate driving condistions. I looked at some converter adds and I am confused? I am thinking B&M 2400? Will it be locked up before that just cruising? I don't even have a tach in the car to know what RPM I am at when doing 30 -40 MPH. My GS does have the performance posi rear axle (3.23 or 3.42 something in that area). I want a little performance, a little softer shift under lite throttle and not to roll 10 mph uphill at idle! It sounds like I need a S/P trans but the money is not there! I can go for a converter if the price is right. So what do "YOU" recamend? Mark
A higher stall converter will help the problems you are having. The stock converters generally stall around 1600-1800 RPM. So a 2400 RPM stall would make the car want to creep less in drive while stopped. Also while cruising it will absorb some of the stiffness of the shifts, but still shift hard under full throttle operation. I like Coan converters, but they are more expensive. If this is just a cruiser and not raced much the B&M will work fine. After getting a price for the B&M I would call Coan and tell them about your car and what you want out of the converter. See what they have to offer, I am sure that it will be more $$$ than the B&M, but sometimes you get what you pay for. Yes, it will lock up before 2400 RPM while cruising, but it will be at a slightly higher RPM than with the stock converter below 2400 RPM. Higher than 2400 RPM it should be about the same.
Thanks Kelly you told me what I wanted to hear ..... and I trust it is right. What had me confused is the following line in the B&M catalouge. Stall speed listings are based on engines producing 230lb. ft. of torque at 2,500 rpm. More torque at 2,500 rpm will give you more stall speed, less torque at 2,500 rpm will give you less stall speed than the stall speed ratings indicated. I think my 350 is rated at 375 lbs of torque @ 2800 RPM. I would think it is safe to say it has more then the needed 230 Lbs @ 2500 RPM needed! I just wanted to make sure I was getting something that was going to be noticable!?! I don't want to spend $400 or more putting in a converter to not feel the differance! When I say my Stock converter seems locked of idle I am not kidding! I am not saying I want it to feel like it is still in park but I dont want to have to bring it up to 2500 rpm before the car moves! If I read this right my stock converter is about 1800 and if I go with the B&M 2400 I will need about 600 more rpm (Below 2400) to make the car move? Sorry if these Q's seem simple to most but if you don't ask you don't know! Mark
Mark, I think most stock converters are closer to 1400 stall. The only way you'll see the true stall is with a trans brake. Converters have 2 halves, the impeller (driven by the engine) and the turbine(drives the transmission input shaft) There is also the stator, which isn't important right now. Stall speed is defined as the maximum RPM that the impeller can turn with the turbine held stationary. A converter with a rated stall of say, 2400, will move the car at much lower RPM's. An efficient converter will break street tires loose well before it's rated stall. That is what you are after. You want the converter to be relatively tight under light throttle, but stall higher when you step on it. A torque converter is the ultimate, you get what you pay for driveline part. It's really important to get it right. Converter manufacturers can tell you which converter is right for you if you give them enough information about your combination.
My goal is simple. Under lite throttle lesson the firm shift from my shift kit. And stop the way my car feels when stopped at a red light in gear (Like it still wants to go!). If I did not know as fact my car was idling @ 600 rpm you would think it was 1600 rpm when sitting with it in gear! As for spinning the tires? When I stomp it now it melts "Both" 225 70's on the back! If adding this converter will make for more of a blast out of the hole its time to up the tire size! Mark
If you are already blowing the tires away, a higher stall will cause the tires to spin even harder from a launch. Most people don't mind having this problem. Actually it's a pretty fun problem to have. Think of the torque converter as a big rubber band between the engine and transmission. Three things affect the stall speed, or how much the rubber band will stretch, how much torque your engine makes, the weight of the vehicle, and the gear ratio. Using a transbrake to test converter stall will only take into account one of these factors (engine torque). When your car is not in a transbrake condition i.e. during a launch, the other two factors come into play also. The more your car weighs, the harder the converter has to work to get the car to move, so the "ruber band" will stretch more. Likewise the gear ratio will make it easier, or more difficult for the converter to get the car to move. Say for instance if you launched a car with a 2.73 gear it would be like taking off on a 10-speed bike in the highest gear, you would have to push on the pedals really hard to set the bike into motion. This will cause the converter to stall higher. On the other hand if you take the exact same car and change the gear to 4.11 it would be more like taking off on a 10-speed bike in low gear, you don't have to push nearly as hard to get the bike to move. So the converter's stall speed would be reduced. I hope this makes sense. So to answer your question, the torque converter will move the car at RPM below the max stall speed. How much the car will move depends on vehicle weight, gear ratio, and how much torque your engine is putting out at the time. The difference between a "good" converter and a "cheap" one is how easily it slips during part throttle operation. A friend of mine had a converter that was so loose we called it the 4-speed converter (it sounded like a 4-speed when you would start from a stop). It had a max stall of 3000 RPM, but it would not move untill the engine got up to 2000 RPM (cheap). A "good" converter will have a tight feeling while cruising even though it will have the same max stall as a comparable "cheap" converter. The "cheap" converter will feel sloshy or loose compared to a "good" one. Another difference is at the track, converters will have some slippage while the engine is at max RPM. A quality converter will have less slippage and therefore you will see more MPH in the 1/4 mile and a quicker ET. So like Larry said, you get what you pay for.
My 350 runs great. As for spinning the tires if I want to it will! If the car is rolling and I hit it the car just go's. If I am sitting and slam it the car will spin the tires up to about 25 mph and at 35 I get a nice loud chirp into second. My problem is just cruising. Trying to get rid of the car wanting to creep when waiting at a red light. And if I just drive normal (wife in car) softining the first to second shift. B&M has a 2400 for $239 and I see Coan has a BOP 2400 for less then $200. Any buddy used either one of these? Mark
Kelly, I spoke to Art at Coan Converters. I told him what I had and what I wanted. He told me their 11" converter (2800 I think) was what would work best for me. He quoted me less then $300 delivered. I can do that. This will be the best of both worlds for me! When the wife drives the car or rides shotgun nice start off's and smooth shifts. When I am alone it's undercoat the quater pannel(s) time! Mark
501 Performance Converters Mark, I have been through this before call perfect converter companytoll free 866-TCC-5015 Walton Hills,OH.Just installed their B-1A HS 13" stock converter With 2200 stall built into it and I love it!! I have a simular build,but my engine is a carbed 3.8 turbo that was flatuntill 2000 rpm this converter put the power range in the right spot , took the snap out of the shifts and idle in gear alot friendliar :TU: I know it will handle torque of a 455 also, as Joe Kelsch runs this in his 71 Buick.He may be able to tell you more about it. BTW. You took the words right out of my mouth in your first post :laugh: The cost was $250.oo and is a work of art!!! :Smarty:
