Need stall Converter advice

[crazyrc]

I run mostly mud trails and as many mud drags as I can make it to.(Few each year). Planning on running a 2400 stall, but not 100% sure if thats what I want.
t400
4.56 gears
40"boggers
540lbs @4400rpm
460HP@5600
380lbs @ 2800
This is not a daily driver, but still sees the road and sometimes up to an hour of highway travel to reach trails. What would you run for a stall. (there's no rocks up here so its all boggin)

 

[Sandman]

I ran a 2400 stall with 40" Boggers and a 454. Loved it but not in the rocks. I got into the rocks more so I ended up pulling it out. In the mud races it was great. the only problem I had was the heat. I ended up running a deep pan and only a large external cooler with a guage on it. Then it wasnt too bad. I say go for it. You wont regret it. In fact, if I get back into the mud, I might consider a 3500 stall.

 

[Drewminator]

I'm running a 2500 stall in my 700R4 attached to a sb 406 running about 400 hp. It's my understanding it's all about where your motor makes hp. The way mine is set up it makes hp higher in the rpm range so that's why I put in the 2500. That way the system does not lock but slips until the engine is getting into its power band so to speak. If your making good hp at a lower rpm you can get away with a lower stall. If your making hp at a higher rpm you want a higher stall so it slips until the rpms are up. Over 45 mph it locks no matter what the rpm so on the hwy it does not slip. I'm in Michigan and don't run rocks but do a lot of trail riding, mud running & sand dunes. The friction of it slipping at lower trail speed & rpm creates a lot of heat. I just added a B&M trans cooler with a thermostat controlled electric fan to help with the extra heat. this year I have only had it out in the dunes and the heat seemed to be under control with the addition. Running the trails in a few weeks with my local club we'll see how it does then - that's when I saw the most heat.

Sorry I'm so long winded - hope I helped.

 

[CHEVY 4WD]

if the converter locks up over 45 then you can have a 2400 stall converter and cruize at 2200RPM or less and never worry about heat? as long as your over 45?

 

[Sandman]

Mine didnt. It all depends on your rolling resistance to the converter. The 2400 Stall in my '68 chevelle drives almost normal as long as I stay out of it. Its easier to keep it cruising down the road. In a Big Blazer with 40"s, my rpm would never stay below 2400 rpm or so-ish if I had to use any gas at all. This was with 40" tires and 3.73 gears! /forums/images/graemlins/eek.gif

Every vehicle is different. My tranny would heat up more on the highway than on the trail. Pushing more wind maybe.

 

[crazyrc]

I'm leaning toward a 2200 stall to avoid some of the heat related problems. I would like to run 2400 or higher, but if I swap to 44's (considering switching to 44's)I need to run a 2200 stall to keep it from slipping on the highway.
40's @ 65MPH = 2450RPM
44's @ 65MPH = 2280
I'm also concerned about heat build up when running the occasional slow speed trail. Keep the comments coming.

 

[tarussell]

Look at Sandmans reply again . He had the same conv. in two different applications and it had a cruising stall of very different RPM's. Just because a conv. is rated at a certain stall speed does not mean it will always stall at that speed - it all depends on the resistance and the power being applied. The stall speed's that are given for each conv. is a general range - they can be loose or tight for each spec.
I think that you are on the right track by matching your gear to RPM at criusing speed but there is more to it than what is on paper. It has a lot to do with power input and rolling resistance.
example : 572 cubic inch motor/3500 conv./44's with 2.73 gears and the line lock on will stall a whole lot more than the same conv. in a truck with a 305 / 6.17's and 31" tall tires with no resistance.
My point for saying this is don't split hairs over a few hundred RPM's in your conv. selection - choose the one that meets your needs off the line and not what your cruising speeds will be - with in reason .
JMHO , Tom