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Originally Posted by Dude Boy
I've got 2 1/2" dual tail pipes on mine with the big 3 1/2" tips. I've never noticed the loss of torque, but you are probably right since I did notice it on the dyno charts quite awhile back. Here's an idea that might let us prove it one way or the other: There's been some talk in another thread about converter stall speed. Since all us V8 guys have one of these, whether we wanted it or not, what if we compared stall speed RPM? The way I understand it, if you are down on torque, your stall speed would be down a bit. If you have more torque than the rest of us (V8 Toilet) wouldn't your stall speed RPM be up a bit higher? I know that if you "cam up" an automatic transmission car to where you kill the engine's low end, you can get some of the "off the line" performance back with a "high stall" converter. Also, some aftermarket companies sell a "low stall" converter for diesel pickups that put out a lot of torque down really low. Maybe we could dyno test our engine's low speed torque by using our own built in dynos (converters). It would just have to be remembered that you run some risk in doing this, such as drive train damage, and overheating your transmission fluid. When I worked in the shop, we would chock the wheels, hold the brakes, do the test really quick, and then slip it into neutral and run at high idle to cool the fluid back down. GM schools warned that you ran the risk of causing minute welds on the contact surfaces of the ring and pinion while performing a stall test with their large displacement V8s.
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I regularly see the stall RPM on my truck's TC...it's about 2200 RPM...when I'm towing at high altitude. Happens when I'm at or above 9000 feet where the engine torque is half or less of the sea level torque. With my 3700 lb trailer in tow and 500 to 800 lbs of people/cargo in the truck, I see the TC reach stall RPM...and stay there for several seconds...whenever I try to start up a 10 percent or greater grade from a dead stop. The truck does
eventually move....but the acceleration is glacially slow...
at WOT it takes 10 to 20 seconds just to get up to 20 mph . You sea level types could probably somewhat duplicate my findings by (1) removing 4 spark plugs, (2) loading the bed with a thousand pounds or so of cargo, and (3) from a dead stop, try climbing the steepest hill in your area.
Since I'm getting a 2200 RPM stall with half or less the torque you guys have...and reports by various folk indicate that even full power trucks also have about a 2000 to 2500 RPM stall, I'd say stall speed is much more correlated to throttle postion and transmission turbine RPM than to engine torque.