Mr. Magoo

Lock-up and Non Lock-up Stall converters?
This stuff is so confusing to me?? :crazy: :crazy:

scorp508

A lockup convertor "locks" up meaning there is no freeplay in it. It becomes a solid piece and almost like another gear in the tranny. It sort of makes it like 4th gear in a manual car.

A non-lockup convertor never locks up and is constantly slipping to some degree.

ralph

Just like it sounds....one locks itself to effectively become a direct link to the transmission and the other doesn't lock and always has some amount of slip. For a track only car, you are usually better off with a non-lockup as they are lighter and generally accelerate quicker. For a stree car, you are usually better off with a lockup. The lockup system consists of a clutch that engages to lock the converter. This reduces heat due to slippage and improves gas mileage.

Mr. Magoo

Thanks guys that makes a lot of sense to me. :)

I’ve been looking into buying a higher stall converter for a 383/Miniram engine I’m having built. Currently I am selling my SLP 2400 lock up style Converter and thinking of buying a B&M Holeshot 3000 non lock-up Converter. I really can’t afford a Yank of Vigilante.

I intend of doing a great deal of driving at the track and street. How much slippage will occure and how noticeable is it? Also is there a switch or something I can purchase to manually lock up this converter?

scorp508

My advice is build the engine first, get it tuned, get it on a dyno. See where the thing makes its peak power and shoot for a convertor a couple hundred RPM above that.

0ski_dwn_it

Man I wish there was a better word than "slippage".

As there is a benifit from the "slippage" which is torque multiplication when it happens. Unlike when a clutch slips, there is torque/Hp lost....

I think this is what really confuses people.......still kinda does me too, until you rember there there is a benefit from the slippage.....

I posted a topic a while ago in regards to that Precision Industries and Pro-built told me to do with my converter (lock-up style) on the strip. Might give you some insight also. In the butshell, they both said the only reason for a lockup converter is fuel ecomony, and heat (which can be simply addressed with a good tranny cooler).

:cheers: :lurk:

0ski_dwn_it

Scorp, you do mean, a couple hundred lower right? :skep:

Also if you go with a non-lockup, a valve needs to be changed in the tranny itself, as the fluid to a non-lockup converter enters in a different direction as a lockup converter. :cheers:


[Modified by ski_dwn_it, 9:22 AM 10/21/2003]

scorp508

Brain fart.

Mr. Magoo

So keep my stock converter in there for the tune and dyno run?
Sounds like the right way to go about it but damn I hate to pull the tranny out for a second time. (I should say have someone pull it out for additional labor costs)

Scorp is this what Ken, Paul & Rick did to determine what converter they should buy?





[Modified by Mr. Magoo, 9:44 AM 10/21/2003]

ralph

Why would you go non-lockup in a street car???

Mr. Magoo

Good question that's why I started this thread to educate myself between the two.

SloRvette

I wouldn't consider the B+M 3000 an option. I've got friends with one in a drag only car. It's very loose part throttle. If you tap the gas it goes to 3000.

The better convertors will be tighter at part throttle so if you're just cruising around the motor won't be at 3000 all the time. Then when you go to full throtle they'll go to the stall speed. For you, since the majority of your driving is on the street, you wouldn't be happy with the B+M.

Stall speed of a convertor is dependant on the torque the engine makes along with the load it takes to get the car going. The same convertor in 2 different cars won't nessecarily (sp?) have the same stall speed. A convertor in a high torque, heavy car will stall higher than in a lower torque, lighter car.

The convertor in my Buick will stall at 3400 rpm on the transbrake at no boost. At 10 lbs of boost it stalls at 5000 rpm. That the difference that torque makes.

Magoo, you've got a ways to go before you need to be worrying about convertors. And yes, if need be, the trans will have to go in and out, maybe several times to get a stall that you're going to be happy with. DO NOT cheap out on a convertor. It'll be money wasted.

Mr. Magoo

:cool:

I'm not worrying I'm trying to learn.




[Modified by Mr. Magoo, 4:50 PM 10/21/2003]

Hole-Shot

In my own opinion, It is worth spending a little bit more to get a high quality converter. Especially since you are putting a lot of effort into the rest of the motor. If you put a stock/cheap converter in, you will be kicking yourself later for not going with a good converter to start with.

For example… my 87 with the stock converter would run 12.1 and then when I switched to a Vigilante I ran 11.8. My 60’ times also dropped over a tenth. No other modifications were done to the car in between that time.

A quality converter is worth every penny. :yesnod:

I think a 3000 rpm Vigilante (w/lockup) would fit your needs very well.
It will still have good street manners and it will launch great.

Good Luck !! :cheers:

CFI-EFI

Converters 101

No amount of wiring will lock up a non-locking converter. The clutches that do the locking aren't in there.

As stated above, the locking (hydraulic) circuit of the trans will have to be modifird for a non-locking converter. Conversely, although it wasn't asked, a trans not equiped for a locking converter (TH400 for examp.) cannot simply have a lock up converter intalled.

There is a difference between stall speed and lock up. A non lock up converter never locks. The slippage diminishes to a managable level (like a stock, older, pre-lock up converter car) as the stall speed is reached. On the other hand, the lock up converter can be locked at virtually any speed, regardless whether the stall speed has been reached or not.

For street use, the higher the stall, the more your daily driving will be below the stall speed. With a non lock up converter, this means slippage. Besides comfort and fuel economy problems, slippage causes heat. Heat is the number one killer of automatic transmissions.

I have a 2600 rpm (rated) stall converter. Eighty five mph is 2400 rpms in OD. Good thing for me, it's a lock up converter. Good luck, and...

RACE ON!!!


[Modified by CFI-EFI, 11:55 AM 10/21/2003]

Mr. Magoo

Thanks CFI-EFI & Hole-Shot, that makes a lot of sense to me. :thumbs:





[Modified by Mr. Magoo, 5:51 PM 10/21/2003]

SloRvette

Magoo, a torque convertor is like 2 fans sitting facing each other. When you get one fan turning, the air from it will turn the other fan. In a car, one fan is attached to the motor the other the transmission, inside the convertor case. The air is the transmission fluid. The convertor maker will change the pitch (angle) of the blades along with the number of blades, and the diameter of the fans, and that is how they change the stall, along with torque multiplication. When those fans aren't turning at the same speed, they're beating the fluid up creating heat.

You can think of stall speed as when both fans reach the same speed.

As was mentioned above, a lock up convertor has a clutch disc in it that is hydraulicly controlled to lock those fans together.

Switch

You may want look into an Edge converter, good price and works for me. I got a 3000 stall, it's a little loose for driving in Seattle traffic, may send it back and get a 2600. It gets the HotCam up and running in a hurry.
Also beware of 2800+ converters in OBD1 vehicles, as the high stall can be interpreted as a transmission problem by the PCM and put it in the limp home mode. Some cars work with them and others don't, so far I have been lucky.

Gordon

flyersfan1088

Thank you. I was waiting for someone to say this.

Chefskeez6

Magoo others know better than me but i really recommend that you get a lock up converter. The only real benefit to a non lock up is weight, you can unplug the lock up for the strip if you really want. The best time to really notice a converter lock up is probably when your going about 50 mph down hill and you take your foot off the gas, the rpms sort of hold, hit the brakes slightly and it unlocks, you can feel it and see it on the tach. It really makes for a better street vehicle to have a lock up.