yurs78

I'm a little confused by the graphs, can anyone help me understand why there is soo much torque below 4500, even 4000 rpms?!!! These are cams in the 240 degrees and they are putting to shame anything in the 220's and 230's, (all of their torque carries past 5000 rpms and doesn't really start till 4500 rpms) Is it the intake?

Also, how "dead' or "flat" is the power of a 240 cam from idle to 3500 rpm? How much are you losing compared to stock power? I'm assuming that there's pretty much nothing their till you get to 3000 rpm, and then it builds like crazy.

Any explanations will be a huge help. I love the torque down low 3000 - 4500 rpm but I just want to know how spongy the engine will be below those rpms.

Thanks!!
Russ

12secSS

iTrader: (30)

Russ,

It is the converter that is doing that, huge torque! The converter has an STR of about 2.2 and it is rated at 4500 rpms. On a street application, this would feel very loose and "soft". But hit the pedal and your will need to hold on tight.

Quik

iTrader: (7)

those are some serious numbers

yurs78

I'm not very smart about all of this, so I really don't know how a torque converter would make such a high number like your engine did and at such a low rpm compared to all of the LS2 engine dyno's I've seen. The converter doesn't add torque, the engine still has to crank it out for it to get to the wheels.

Just like my first question how can a 240 cam make way more torque than any other 220's or 230's cam I've seen. (475fwtq with tfs heads and 90mm fast 230's cam vs. your 500 to the wheels!) And the power is made at a lower rpm 4500 vs. 5200. (this I think has a little to do with the tc)

Is there some effect where you have such a cam so large in degrees, or at so many degrees it doesn't change much after that, that it "maxes out" what the heads can deliver. So it drops the tq peak to lower rpms? (sorry if that was the dumbest thing you've ever heard, that's all my little brain could come up with )

Just like you say from your post I'd imagine that this engine would be lousy below 3000 (need for high stall and lack of power out put) but above that it would totally rip.

Thanks for the help, just trying to understand. This is the best 6.0 dyno sheet, on 91 octane, I've ever seen ( by a long shot) so I want to know as much as I can.

Later,
Russ

yurs78

I also don't know why more people haven't chimed in and talked about this. If you figure a modest 15% drive train loss that puts you at almost 590 at the crank at 4500 rpm. That is quite a bit more that the stock 112 kit can do.

Excellent work, (or luck depending on how you look at it), great to see such encouraging results.

Russ

12secSS

iTrader: (30)

Actually yes the torque converter does add additional torque down low in the rpms, hence why it is called a torque converter. The design of the stator and impeller/turbine fin design helps to multiply torque, which is called an STR or Stall Torque Ratio. So a converter with a typical 2.0 STR is actually multiplying torque 2:1 to the tires. So at 300rwtq, an STR of 2.0 would increase that to 600rwtq ... for the inital hit of the throttle. This is the reason why automatics will 60' better then manuals at the track (also the 1st gear in the 4L60 helps out as well) even when compared to TH400s or TH350s. I hope this helps Russ.

yurs78

It helps a lot, I didn't know that you could actually have a better hp to the ground just from the TC. I know that lighter trannys 80e vs 60e rob less power and manuals are a little better than automatics. But I never thought the TC could increase the power to the ground that much.
Thanks for your patience and help.
Russ

GreenBlood

iTrader: (6)

sick, keep it up...

Yogi Bear

The TC multiplies torque, not HP. There is actually a small HP loss going through a TC due to frictional losses in the fluid. Think of it as being similar to a manual trans in second gear with a slipping clutch. The clutch slips some, losing power to heat, but allowing the motor to rev higher, which puts the motor at a higher point on the torque curve; while second gear provides a multiplication of the torque. And this is before the automatic transmission, which further multiplies the torque (in lower gears).

I hope that this is not too confusing.

BadManLS1

iTrader: (1)

Was the converter locked?