Outer Limits 4x4 Board

what are people thoughts on running a t400 with a 2500rpm stally nehind a 6.2 oiler? the car is geared so I am using these kind of revs on the slow stuff anyway does anyone for see any problems with this combo??

Thanks

They're governed at 4k and optimum torque is at about 2k, so if your like your auto fluid boiled

thats what i was thinking a little high.
about 1800 would be ideal

Tiny if you have that TH400 im hapy to take it off your hands and you can buy one with a lower stally???

I run around 1000 stall behind mine, works really well

DIRTY ROCK STAR wrote:Tiny if you have that TH400 im hapy to take it off your hands and you can buy one with a lower stally???

will work something out mate, I think 1000 to 1200 would work well

thanks for the input guys

yeah apples dude let me know.

Max torque is at 1700rpm, max power is at 2600 rpm. After 10 odd yrs of R&D the automatic wharehouse settled on 1700rpm stall convetrors. They make their own and sell them but a little pricey at $1100 each.

This is interesting Nev as it seems quite high. Maybe in a VERY heavy car it would be OK but I am pretty sure that my Dad's Hummer ran about 1200RPM from memory at 3 tonne dry.

These motors produce about 300nm from idle - it seems like a lot of wasted rev range to me, but maybe I am missing something.

Maybe in a performance application or with a turbo engine 1700 might be ideal, but for an NA it seems a bit high. I'm no expert though.

Steve.

Quote from banks
http://bankspower.com/Tech_understandstallspeed.cfm

Let's start by illustrating how the stall speed works. Even under light loads, a vehicle with an automatic transmission will start moving as soon as you take your foot off the brake. The stall speed comes into play under all load conditions. When we talk about stall speed, we're referring to engine RPM. If the vehicle isn't moving by the time the impeller reaches the stall speed, either it will start to move, or the engine RPM will no longer increase. In other words, stall speed is the engine RPM at which the torque converter transfers the power of the engine to the transmission.

Now, let's say you need lots of power, either to make a fast getaway or to start with a heavy load. You'd rev the engine up to a point where it delivers more power before letting up on the clutch pedal. It's under those same circumstances that the stall speed becomes important. The torque converter will allow the engine to build RPM without turning the output shaft (the turbine) until the stall speed is reached.

Unlike gas engines, diesels develop massive amounts of torque (pulling power) at low RPM – enough that it's possible (and, in fact, desirable) to get a heavily-loaded diesel truck rolling by simply easing off the clutch without touching the accelerator. Banks' dynamometer tests show that Ford's 7.3 liter Power Stroke hits peak torque at 1,600 RPM and begins to drop off at around 1,850 RPM, while the Dodge's 5.9L Cummins engine peaks at 1,400 RPM and drops off at 1,800 RPM. As RPM continues to rise, torque decreases even further.

How would you translate this to a torque converter? With a low stall speed. But both the Ford and Dodge torque converters stall between 2,000 and 2,500 RPM – so with a heavy load, the torque converter won’t start turning the rear wheels until well beyond the engine's torque peak. In this case, the stall speed is too high - it is literally impossible to get the engine's full power to the rear wheels! In order to access all of the engine's potential power, the stall speed must be lowered.

zagan wrote:Quote from banks
http://bankspower.com/Tech_understandstallspeed.cfm

good bit of tech there, thanks

hey twon, got the box on the way, will let you know....mail me biatch