Converting to a T400, couple of questions
Launching!
Joined: Jan 2003
Posts: 218
Likes: 0
From: NV
Sounds like a fair amount of slip if that RPM is correct. Using mine as a reference, I had a 4800 stall, 4.10 gears, 28" tires and trapped 126 at 6400 RPM. I would data log a run and see what the RPM is so you get a more accurate read, don't trust that stock tach to much. You should be closer to 145+ mph at 6800 RPM with your gears and tires.
Assuming that not everyone has a wideband 02 and a laptop with EFI Live or similar, we can use these "Indian Methods" and get a fair idea of how much slippage there is with an unlocked vert in a TH400/350. Yours was only 200 RPMs over what the math made it to be. Now, pddye was using his stock tach, so we can throw that number out, assuming he had a time-slip with 125 mph on it, using the calculator with no slippage he would have only been taching 5595. If he was taching a true 6800 RPM with his setup, that would have been 152 mph (assuming no slippage). We can use Dan's amount of slippage and Mr. Pddye might have been taching 6000 + 200 = 6200 @ 125.
This is not scientific of course, but we know there is X number of RPM over what a normal 1 to 1 calculator tells us, as if we all had 6 speed trans cars.
Hopefully the "OP" can garner some rough idea from this info. Good discussion guys.
Last edited by ChevyGoldfinger; Sep 25, 2008 at 01:59 AM.
Yeah, when doing the math, I thought my data was off because my TC seemed too efficiant, like 3% slip. The Neal Chance was built specific for my car though so I guess it's going to be decent, but not that good. 4800 stall on T-brake and about 3400 on foot brake. What's an average efficiancy for most TC's, 90% or so?
Last edited by DanZ28; Sep 25, 2008 at 12:08 PM.
Found a calculator here for slippage http://www.tciauto.com/Products/Tech...culators.asp#4 .
Using the OP data, he would have almost 22% slippage, not very efficiant at all. Of course thats using the 6800 RPM data.
Using the OP data, he would have almost 22% slippage, not very efficiant at all. Of course thats using the 6800 RPM data.
Launching!
Joined: Jan 2003
Posts: 218
Likes: 0
From: NV
Found a calculator here for slippage http://www.tciauto.com/Products/Tech...culators.asp#4 .
Using the OP data, he would have almost 22% slippage, not very efficiant at all. Of course thats using the 6800 RPM data.
Using the OP data, he would have almost 22% slippage, not very efficiant at all. Of course thats using the 6800 RPM data.
Between that one and the one I posted earlier in the thread, you should be able to calc just about any combination of setups. Good info.
I'm heading to the track next sunday so hopefully I can figure out whats going on. I'm hoping my converter isn't junk. I knew the stock tach would be off but didn't think that far. If I log the run with my hptuners would have have a more accurate tach reading? I forgot the laptop last time up so I couldn't log my runs.