Originally Posted by DaveB

That is kind of the point for the SAE correction. Naturally when temps are hotter, the ECU will pull timing and add fuel to keep the motor from detonating. Every car using an electronic control will do this. Same goes for baro pressure. The pressure sensor relays the baro information to ECU because when pressure is high, more 02 is freely pumped into the motor therefore fuel must be added or else the motor will experience detonation. The SAE correction is the generally accepted correction factor that compensates for what the ECU will do under ambient conditions. However, it is just an estimate. If the motor is scalding hot, it may impact power somewhat, though on the track, my G35 and my friend's G35 doesn't seem to care if the motor is hot or cold because trap speed remains constant.

Concerning this particular dyno, the SAE CFs are wildly different 0.94 vs 0.99 (close to ideal). It appears that the first dyno was done on a day what had extremely good air (high baro pressure) and that the second dyno was under more typical ambient conditions. Though a 0.94 vs 0.99 doesn't seem like a lot, it really is when it comes to dynos. The data tends to get skewed the further the SAE CF gets away from 1.00 (higher or lower). This dyno shows that his car actually made less power with the Crawford High Flow Cats, Crank Pulley, and Unichip. IMO, I think the car is probably making close to the same power it did during the first dyno, but the SAE CF of 0.94 skewed the data a bit. Also, from the dynos I've seen for UDPs, high flow cats, and the Unichip, none of these mods make any measureable power. Unichip isn't a piggy back adjustable ECU. Correct?

Also, wasn't it you that actually saw a small loss with the Crawford high flow cats?

Originally Posted by G35_TX

DAVEB = CLUELESS G35 OWNER

LOL!!! Another stupid post

So your saying the Dyno knows when the ECU is pulling timing and cutting power because of engine coolant? Really? Wow, got any data backing that up?

Btw, this proves you do not have a clue about how dynos work or obviously the G35 period.

......Well let's see. My car was dynoed once 4 times in a row, maybe it was 5. I forget. But it lost almost 15 hp because of back to back pulls. If a DYNO corrected for that then my car wouldn't have lost 15 hp. It lost it because the car was heat soaked, coolant temps were way to high, the car removed timing.

Originally Posted by DaveB

Well let's see, my car did a 14.35@97.5mph, a 14.39@98.1mph, and a 14.32@97.8 all on back to back passes within minutes of each other. No cool downs. I think we can be certain that the engine would be pretty dang hot. Then I let the car cool for an hour and the car ran 14.41@98.0mph. 45 minutes later, it did another high 14.3. All 60 foots were within .05 seconds of each other. If anything, my car was quicker with a hotter engine.

Interestingly and something you apparantly haven't seen, but nearly every G and Z dyno I've seen shows the VQ gaining power after each successive pass. That kind of data goes against what you're preaching because we can be pretty certain that each dyno was done within 5-10 minutes of each other.

Most gearheads know that an engine makes the best power when the heads and block are hot and the intake charge is cold.

Who's right? Who's wrong? We'll never know.

Originally Posted by erikill

I figured I'd take the opportunity to check on SAE's website. I don't see any ECU corrections here?

Originally Posted by G35_TX

1) We are talking about a Dyno here not a track. There are more variables on a freakin track than a Dyno. And the car is getting HEAT-SOAKED by not moving anywhere on a dyno.

Originally Posted by G35_TX

Hmm, strange, all the dynos I have seen show then loosing power the more passes they do. Where is your dyno? Where is your experience of over 100+ dyno runs? Didnt think so, you don't have any.

It's obvious you aren't right here. You proved that above.

Originally Posted by DaveB

So a car running on dyno with the hood up, a 50mph fan blowing on the motor/raditator, and spinning a 2,000lb roller will run hotter than a car running with the hood down, never shut off between 3 passes, accelerating a 3,500lbs w/driver, and having to deal with aero dynamic drag? Is it me or is the dumbest argument I've ever heard

Originally Posted by trey.hutcheson

Hard to argue, but I've never been fortunate enough to attend a garage that had a fan capable of even 50mph. Most garages have itty bitty fans. Hell, I've seen posts on here and my350z(mostly newer guys) that claim a fan wasn't even used during a dyno.

Regardless, we're getting a bit off topic here.