any benefit to a low stall converter

[Tate]

Originally Posted by madmikeismad

And how did rpm to spool increase? rpm is rpm, turbo doesn't know if the converter is tighter or not. Did you change anything else? Or maybe the 2100 just climbed faster so you couldn't tell exactly when it spooled?

I was wondering that myself.

[madmikeismad]

Originally Posted by Gasoline Sucks

This is how I feel....

I pulled my convereter out sent it out to get loosened up asked for 1800 got 1500. When I say 1500 I mean hold it on the mat on the brakes and it will not go over 1500 until the rear tires break loose.

Off the line sucks with 3.55 and 33" tire especially any kind of towing.

Thats what goerend did to me. Sent my 1400 back for a new 2000, still doesn't break 1400 at the line until chargers light, which makes it creep through the brakes because my reflexes on the throttle are terrible I think they accidentally thought I wanted just a new 1400.

https://www.youtube.com/watch?v=1Did...YR0Tvw&index=4

[CorneliusRox]

Originally Posted by madmikeismad

How is it cooler in traffic? Mine overheats easier with tighter converters.

And how did rpm to spool increase? rpm is rpm, turbo doesn't know if the converter is tighter or not. Did you change anything else? Or maybe the 2100 just climbed faster so you couldn't tell exactly when it spooled?

It should be cooler with a tighter converter. Less slipping means less fluid being 'sheered' and heated. It's making it more efficient (efficient as a coupler, not necessarily a more efficient truck).
The only way I could see it being hotter is if you are going slow where the loose converter will not be transferring any real force through the trans, and the low stall might be, but for normal operation it should definitely be running cooler.

And if anything, I feel like my turbo lights at a lower rpm with a lower stall because it gets the load earlier. If we're talking locked and locked, there is no difference obviously. It just takes longer to to get to that rpm if it's super cold and the cold fluid lowers my stall even more, so my engine is getting bogged out long before the turbo thinks of lighting. That's pretty rare though.

[zfaylor]

Just some food for thought:

http://www.converter.com/faqs.htm

http://www.edgeracingconverters.com/...page=page&id=4

Stall isn't necessarily black and white. Ultimately there is a true stall to the converter but oftentimes this stall doesn't matter because very few in the diesel world have a trans brake. We are more worried about brake stall at the line or flash stall while moving down the track.

[John_DeereGreen]

Originally Posted by madmikeismad

How is it cooler in traffic? Mine overheats easier with tighter converters.

And how did rpm to spool increase? rpm is rpm, turbo doesn't know if the converter is tighter or not. Did you change anything else? Or maybe the 2100 just climbed faster so you couldn't tell exactly when it spooled?

I don't know why it's cooler, I just know it is.

I know it takes a little longer to get on top of the charger now, and it builds boost a little bit later than it did with the looser converter.

[stubz616]

Originally Posted by John_DeereGreen

I don't know why it's cooler, I just know it is.



I know it takes a little longer to get on top of the charger now, and it builds boost a little bit later than it did with the looser converter.

As the fans shear through the fluid internally in the converter, heat is created. A looser converter is less efficient at reaching the fluid coupling (the point at which the truck has to move or "stall speed") than a tighter converter due to the number and pitch of the fans inside. So it has to shear the fluid more times and at a faster rate (higher RPM) to get the same amount of work done that a tighter converter can achieve at a lower RPM. That's why lockup usually cools transmissions down, because your eliminating that fluid coupling and going through the clutch instead. Once you understand how a converter works it's pretty easy to understand. They look complicated but the theory of operation is generally simple.

[jlbayes]

Originally Posted by ARbowhunter7

I've got a 1500 stall triple and I hate it. Running a spool-valved 467 and it's a lag-machine under normal traffic conditions (especially off the line).
I normally drive like a senior citizen on the street, but if I need to outrun another driver from a light (upcoming merge, need to change lanes, etc,) I can't do it without making a scene (lots of noise and smoke).
I'd probably like it a lot more with a set of towing twins, though.


Sent from my iPad

Originally Posted by Gasoline Sucks

This is how I feel....

I pulled my convereter out sent it out to get loosened up asked for 1800 got 1500. When I say 1500 I mean hold it on the mat on the brakes and it will not go over 1500 until the rear tires break loose.

Off the line sucks with 3.55 and 33" tire especially any kind of towing.

x3 hate my current low stall converter. never liked it since the trans was rebuilt last time. doubt i'll go lower than stock again.

[John_DeereGreen]

I could understand why you VP 24 and 12 Valve guys would say you hate a tighter converter, especially with larger chargers. That would be a pain in the ass to daily drive.

[silvercummins96]

I preference a tight converter. My Allison swaped 12v with twins and stock stall was a pain to drive the truck wouldn't move till 1600 and by then the twins lit. If it was wet out you almost couldent move it on a hill. I had gerond rework it to as close to my 15LC dodge converter as he could and love it. Takeing of loaded heavy is slower to spool but that's fine


Sent from my iPhone using Tapatalk

[fox]

You can take 3 different engines and recieve 3 different stall speeds.

The stall is defined by the ability to hold a given amount of torque. ( with a locked input shaft of the trans) (Or converter output )

Test this by different tunes on YOUR engine.

It is near impossible to say a converter will stall at a given RPM ( like 1600 ) without knowing the engines ability!!!!

[CorneliusRox]

Originally Posted by fox

You can take 3 different engines and recieve 3 different stall speeds.

The stall is defined by the ability to hold a given amount of torque. ( with a locked input shaft of the trans) (Or converter output )

Test this by different tunes on YOUR engine.

It is near impossible to say a converter will stall at a given RPM ( like 1600 ) without knowing the engines ability!!!!

Right, and I think most understand that. That still doesn't change the fact that saying you want a 1600rpm stall is going to give you a slightly tighter converter than the stock 1800rpm stall. It'd be nice if there was a standard (1800rpm stall at 800ftlbs) or something, but I haven't head of one.

Also, if you're dealing with a trans shop with a ton of experience (goerend, firepunk, etc...), you're probably going to get your best bang for punk by talking to them and letting them give you some feedback on how their converter works/feels.

[zfaylor]

Originally Posted by fox

You can take 3 different engines and recieve 3 different stall speeds.

The stall is defined by the ability to hold a given amount of torque. ( with a locked input shaft of the trans) (Or converter output )

Test this by different tunes on YOUR engine.

It is near impossible to say a converter will stall at a given RPM ( like 1600 ) without knowing the engines ability!!!!

Exactly. The flash stall of the converter rises drastically as torque increases. However, as mentioned the true stall of a converter at least gives you an idea of how it is going to react. Quick spooling twins produce enough torque to handle a lower stall converter. A big single typically likes a higher stall because it likes the rpms and doesn't produce enough low end torque to flash the converter. It is a vicious circle with a big single if you get the stall too low.

[kawi600]

low stall is great for a truck thats properly set up for it. With this single, stock cam, stock compression (swirl and efficiency). Lower end of the timing range. Maybe marine injector pattern. Mine seems to like that combo. Id say a 64/12 would be the max Id use on my truck. Anything bigger would be mosquito control driving around town.
If you want that sort of power AND want lots of top end youll need tow twins or triples depending on the range you want. Or maybe crazy carl's mean-lookin' blower setup.

If you put a low stall converter on a truck thats set up like most are, with top end in mind, youll have a laggy smoker.
Maybe a spool valve would help in this scenario? If I had the coin I might try it out for the hell of it.

One thing I dont see much talk about is what low end torque does to the transmission. Seems like a big part of the upgrades was increasing the coupling pressure to keep the plates from slipping. Do we get that sort of clamping at low RPM even with the 48RE pump?