I'd guess around 5 whp from doing the fan coversion. All the gains are pretty much noticeable in the low rpm range, so they won't show up in the dyno. At least the 3 times I've dyno'd my car it was around 3000-3500 that the torque converter actually locked up fully. Based on that it won't show much on the dyno.

 

there are several things (low rmp) that don’t show on dyno - particularly with AT and on dynapack... that's why I always have tuner do road tune after dyno tune - to dial in off idle to 3K.

Problem is too many people only trust numbers, not their own ability to notice differences in their car...

 

hey anything that will get our autos up and going quicker is a good thing.

 

you dont loose that much to the drivetrain... 5-10 at crank should be closer to 3-8 at the wheels.

 

I wonder consider the gains are at the lower rpm where the TC is unlocked, he might be more right than wrong?

 

possibly, but not to the tune of 70%

 

Well I think he meant 5-10 at the crank to correspond to 3-8 at the wheels. So something like if it was a gain of 5 at the crank it would be 3 at the wheels. Or 6 vs 4, 7 vs 5, 8 vs 6, 9 vs 7 and 10 vs 8.

Just a guess

 

you used my numbers... his number were 5-10 = 1-3.

 

Then I agree with your numbers. But perhaps it might be 1-1.5 hp lower with an unlocked TC

 

I wasn't really trying to be exact, i just tossed those numbers out. If you want me to be exact, i can be.

Well, what is typical drivetrain loss with a 6MT? Lets say 15%

(i'm going to round up fron 298 here) 300HP- 15% = 255HP to the wheels approx.

Say we gain 10HP giving us 310HP, same 15% drivetrain loss = 263.5HP

10HP gain at the flywheel = 8.5 HP at the wheels in this example.

So i'll modify 5-10 crank = 4-9 wheels with a manual

Automatics rob a little more power. Maybe 18% i think is the number i heard for the 5AT (up to ~20% for some autos)?? Plus if the converter is unlocked it might rob a little more. I was actually thinking 5AT when i tossed those numbers out.

We can talk about theoretical gains all day. Only way to really know is toss a '03 sedan on a dyno, and run it with the stock fan and then remove the fan and make another pass.

 

That’s a first. I should use it as a sig for prosperity.

Too bad its more fun to disagree/debate (until it gets old).

 

15-20% is the general concensus for AT... cant get that low on dyno for AT though... doesnt register till 3K rpm.

 

anyone have a picture of this setup? i'm curious to see the mechanical fan on a g35

 

I would think you'd see potential gains above 3000rpms because the contention is the mechanical fan places a lot of inertial drag on the motor therefore this should be readily seen as the rpms progress.

As for the TC "locking", I've been reading up on the RE5R05A tranny lately and the TC can operate in three modes: open, slip lock, and fully locked. The slip lock function of the TC is actually pretty ingenious.

 

We need to remember that the mechanical fan isn't engaged all the time either. The only time it's engaged is if the coolant temps are high (I believe that number is 230 degrees) and the car is at a speed below approximately 25mph. At speeds above that and/or coolant temps in normal range, the fan is simply freewheeling along. Many think the fan is spinning at the same speed as accessory belt, which isn't true unless the fan is engaged. Secondly, the fan itself is pretty small and light. The clutch assessbly has a bit of weight, but it's small in diameter therefore it doesn't have real significant inertial drag. Now when the fan is engaged, you'll definitely loose a bit more power compared to the e-fans. But when the mechanical fan is engaged, it usually means the motor is piping hot and the ambient conditions are hot so the car will be doggish already. So what's another 3 to 5whp at this point when the VQ is already down 20whp?

Maybe this winter I'll dyno my 03 for the hell of it and yank the mechanical fan on one run to see what happens.