converters

[madhat]

How much rpm difference does getting a higher stall converter result in? ...Like the difference between stock, 2800, 3200, 3500...

 

[chris718]

it will usually go to the rated stall speed with the braskes or t brake applied and while under high boost.without boost there isnt much difference unless its above 3600 and the engine is hi strung.

 

[chrisgarrett]

stall

I don't really understand the concept of "stall". What is it and why do I need a higher stall with a bigger turbo? Thanks, Chris

 

[madhat]

chris, I'll explain it as good as I can, but I'm sure someone more knowledgable will come and aid me.
With a bigger turbo comes more lag and boost coefficent or something like that...basically lag is throttle response and the other is what rpms the turbo starts spooling(that's what I was told) but, it seems like everyone just uses lag, I sure do. The bigger the turbo is, the more air it takes to get going, so it takes more rpms before you get that wonderous boost. Our stock converters max out at 2400 rpms...they "stall" at that speed...basicaly, to me it seems, that when you power brake it, it will go up to 2400rpms(approx) That is assuming you have a turbo that has started spooling by that point...If you have a turbo that takes a 3500 "stall" it prob wont start building boost till like 3000rpms, so the stock converter will only go up to 1700rpms because it doesnt have boost to produce the power needed to spin the converter faster. So, for a fast launch, you would choose the higher stall so that you could launch with boost...rather than launching without boost and being super-slow for a sec like me!


in short...infact, maybe you should skip all of that above...but I'm not deleting it because I already wrote it!

stall=how high your engine will rev while power braking
higher stall with bigger turbo lets you leave with more power so you can be fast-r!

 

[chris718]

your last 2 statements should answer the other gentlemans qs also.the more stall the more power available on launch because horsepower and torque are made at higher rpm levels than that attained with a stock convertor.this means the engine will move the wait of the car with more power because you dont have to accellerate into the power band before it responds.

 

[madhat]

other gentleman? do you mean me? well, chris, I hope I helped...

but, what I was asking is when you get a higher stall converter and drive on the highway, how much higher rpms will you be running...we run stock at 70 w/ like 2200rpms, but what about with a 3500 stall, what rpms would you run at 70...because there is more slipage w/ a higher stall and therefore, rpms should be higher at the same speed. I was just wondering how negatively it would affect someone who daily drove their GN to go from a stock lock-up to say a 3500 non-lockup...just curious about the affects of drivability...

 

[chrisgarrett]

converter

Yeah, I would like to know too. How would a higher stall say 3000 to 3400 affect a grocery getter? Chris

 

[chris718]

with o boost itll be barely noticeable ,and with the lock working itl be the same as a stock convertor.ill try to have others reply with combo info so its not just me blowing smoke

 

[madhat]

that would be great...I have a question though...if the difference at cruise is tiny, why do they say there will be a loss of economy?...or is it just that there will be more slipage at high rpms. I guess my big question is if going to a non-lockup will hurt me. I know that heat will be slightly higher because of the higher % slipage. So, I'll just wait for some other responses to see the diff.

 

[chris718]

stall speed is directly related to input torque.at cruise speed boost is so low or non existent that stall speed suffers due to the lack of input torque of a 3.8 liter engine with its restricted intake with a non functioning turbocharger or 0 manifold pressure.with a carbuerated motor this is drastically different.

 

[justabuickv6]

Chris's converters are GREAT!

I recently purchased a 9x11 3600 lock up from him. I had been using a stock D5.

I drive my car everyday. The only time I notice a difference is if I take off from a start a little faster than normal or power braking. Normal driving and highway driving there is no difference.

Hopefully, that answers your questions. I went from a stock D5 (2400 rpm) to a 3600.

Just make sure you have an external tranny cooler in addition the stock one because of the added heat.

 

[madhat]

I have a six pass, but I also have another post about a house AC condenser w/ like 30 passes and I was wondering if that would work much better...I'm not so worried about temp w/ it, more about if the pump can handle the distance it would be pumping...any ideas? ...if it is too much for my pump, I can always just use my B&M transcooler I havent installed yet. So, justa, does it feel more pepy of the line?...and if I may ask, how much was it?