The dips are a result of the ECU learning to pull timing. It is part of the learned map, it didn't happen on the dyno.

I agree, the dyno is just showing what the ecu has learned to do in the weeks/months/whatever up to that point. What I am wondering is would a custom map match my car better so that the ecu would not have to pull timing at those points?

Yes, it would.

my wallet hates you :P

Ditto! Damn you all and your knowledge! :evil:

I love lamp!

^^^^^^ :huh: so who all went wheres the rest of the #'s?

Matt - what did your car put down :?: Did the rice pipe help? Wanted to know what you did with those wheels on it? Give me the info.......... :lol:

hah, he gained some hp with the straight pipe, and lost a bunch with the wheels.

BTW: That's anything but a "rice pipe". :lol: Rice is stuff that looks fast but isn't... that straight pipe looks like shit but goes like hell... :lol:

Yesh, the wheels scrubbed a bunch of power, as I thought they would. So with new pipe and Wheels, I put down 221 HP, still not too shabby. it's hard to tell what reality is with my higher elevation ecu only running at altitude for a brief time.

I was woundering more so to put a finger on why may #'s where lower when we went back to back. Wheels must play a big difference in power!

Wheels do make a huge difference in power to the ground.

So do big brake kits. The higher the unsprung weight, the more drivetrain loss to teh wheels. I'll bet Mike can't notice the difference though. It's hard to notice that small a change in HP.

I ran with 18 the first time and got a 228/226/and a224
I never posted my results the first time!

Heavy wheels affect accelreation but not power. Matt's power loss comes more from his tires being too tall than from the extra weight.

We are running the same size differnt brand I have a yok avs 100 235/40

What he said.

I thought heavier wheels will change your dyno readings... someone wanna explain this to me if that's not the case? Then explain it to the guys over at Sports Car Revolution on Speed Channel where they dyno'd their RSX test car and noted the loss due to the big brake kit they installed.

IIRC: heavier parts = more drivetrain loss = less torque applied to the dyno = lower tq and hp numbers (since dyno hp is calculated from the torque)... what am I missing?

They used the same wheels? No upsize in tire diameter? And what dyno did they use? Load-based dynos shouldn't be affected by rotating mass, but inertia-type dynos might be.

I'm not sure, I only saw the "after" episode, where they installed a BBK and an exhaust and lost horsepower. :lol: They were all confused and had to make a phone call to someone that knew better to tell them it was loss due to the BBK's additional inertia becuase the rotors were so much bigger (the BBK was actually lighter than the stock brakes, but the rotor diameter was much larger). In the end they decided it was acceptable loss because they'd be able to go so much deeper into the corners that overall the car would be faster ont he track.

Probably just day-to-day, dynos-never-lie :roll: differences. Plus, high-strung factory engines, like the RSX, S2000, 350Z, etc. tend to lose power with typical bolt-on exhausts.
I still have a hard time buying the rotors causing that much of a difference. The calipers and pads wouldn't affect the rotating mass at all. Yet another testimonial that dyno results all need to be taken with a large pile of salt.

This is nothing new, but I'm confused also.

Doesn't the mustang dyno measure based upon how quickly it can accelerate the rollers? (I suppose that would be inertia based - duh).

How does a load based dyno work. Does it measure how much it can resist the wheels? If so, wouldn't a heavier wheel, brake rotor affect this also?

I have heard the same issues quoted with HKS's dyno.

Mustang dynos measure the actual amount of torque applied to the rollers by measuring the resistance of the extreme large electric motor attached to them. Inertia-based dynos measue how fast the car turns a heavy drum.

Where do you guys get your AWD's dyno'd?