Rear wheel HP estimate

[Paul Workman]

Originally Posted by Hib Halverson

420 at the wheels..SAE-corrected or standard-corrected?

Wel now... that IS the question.

It seems SAE standards evolved over time, introducing the oppotunity for different results for the same run, depending on which "standard" was applied. Add to that some calibration issues, and operator's attention to detail.... Makes for ambigeous results at best.

P.

[Fully Vetted]

Originally Posted by Pete

When i dyno'd that Z it made 425 SAE Corrected

I heard Corey got 428 out of it.

I think 430+ should be possible from that Z but then again every Dyno is different 420-430 is withen tolerance...

Yeah, you've talked to him since I have. I'll have to update my sig!

I'm still chasing Paul for power on stock cams, though.

Originally Posted by Pete

Since then i re-ported my plenum/IH's a bit bigger i also mention i reduced rotational weight between pullies,ATI balancer,clutch/flywheel i'd say 25lbs maybe more and about 200lbs dead weight.

Pete, did you do the lightweight pullies on my car or is that something Michael did after you worked on it? I'm trying to determine if your 425 number was done before or after those were installed.

Originally Posted by Nacho_ZR1

Wow how'd you reduce 200lbs? Inquiring minds wanna know

Going from a steel flywheel to an aluminum one is most of it.

[Fully Vetted]

Originally Posted by Paul Workman

Wel now... that IS the question.

It seems SAE standards evolved over time, introducing the oppotunity for different results for the same run, depending on which "standard" was applied. Add to that some calibration issues, and operator's attention to detail.... Makes for ambigeous results at best.

P.

Paul, please explain the whole "SAE corrected and standard corrected" situation. I know corrections are made so that different pulls at different altitudes can be compared but that's about the extent of my knowledge on this. And I'm not even 100% confident I'm correct on that!

[Nacho_ZR1]

Originally Posted by Fully Vetted

Going from a steel flywheel to an aluminum one is most of it.

The steel flywheel weighs that much??????

[Fully Vetted]

Originally Posted by Fully Vetted

Paul, please explain the whole "SAE corrected and standard corrected" situation. I know corrections are made so that different pulls at different altitudes can be compared but that's about the extent of my knowledge on this. And I'm not even 100% confident I'm correct on that!

Actually, I'm sure several can explain this. The floor is open...

[Pete]

Originally Posted by Nacho_ZR1

The steel flywheel weighs that much??????

Stock flywheel is 36 lbs, aluminum is 13.5lbs almost 23 right there.
Spare tire and tools 50lbs.

http://zr1specialist.com/HAT%20Web/T...0Reduction.htm


Pete

[Pete]

Originally Posted by Fully Vetted

Pete, did you do the lightweight pullies on my car or is that something Michael did after you worked on it? I'm trying to determine if your 425 number was done before or after those were installed.

I think he did the pullies afterwards they are not my pulley design,the older pullies were a bit too heavy for my taste LOL

Don't chase dyno sheet #'s if that's all you want i can give one just tell me what #'s you want.LOL
Like i mentioned before all dyno's are different i used to go 3 different dyno's and all were different but withen 10rwhp one was way out there low about 30,i'm sure if i droped off a few stacks of cash they would get me 30 lol
This why i say 420-430 is withen tolerance.
My Z did 466 on one dyno and 474 on another which do i believe,of course i will post the higher # :-)
Dyno's are tuning device/tool.

Pete

[Paul Workman]

Originally Posted by Pete

Stock flywheel is 36 lbs, aluminum is 13.5lbs almost 23 right there.
Spare tire and tools 50lbs.

http://zr1specialist.com/HAT%20Web/T...0Reduction.htm


Pete

Yep. The rotational mass difference has been demonstrated to be the equivelant of ~ 15 rwhp on an inertia dyno comparisons. Might be worth an tenth or so off the 60 foot times, ya think?

[Nacho_ZR1]

Originally Posted by Pete

I think he did the pullies afterwards they are not my pulley design.Pete

So do you sell lightweight pulleys or have a source that does? I'd like a set

[Hib Halverson]

Originally Posted by Paul Workman

Wel now... that IS the question.

It seems SAE standards evolved over time, introducing the oppotunity for different results for the same run, depending on which "standard" was applied. Add to that some calibration issues, and operator's attention to detail.... Makes for ambigeous results at best.

P.

That is not correct.

SAE Standard J1349 has existed for decades and is still used today. Virtually all chassis and engine dyno operating software corrects to both "standard" and SAE. Some also correct to various DIN standards, as well as the JIS standard.

The difference between "standard" and "SAE" is the atmospheric conditions to which the dyno data is corrected. The makers of aftermarket performance enhancments like "standard" corrected because it typically makes for "bigger" number. Engineers always use "SAE" corrected because the SAE J1349 standard specifies an atmospheric correction factor that is more "real world".

The executive summary of the two atmospheric corrections is: "standard" considers that the engine was run on a 60°F day with 0% humidity and a barometric pressure of 29.92 in-Hg. SAE J1349 considers the engine run on a 77°F (25°C) day with 0% humidity and a barometric pressure of 29.234 in-Hg (99 KPa).

How can these two standards affect dyno results., during a recent chassis dyno test I did with a 2012 Z06, if I correct the data to standard, the best of four passes was 473 at the wheels. If I correct the data to SAE J1349, it was 454.5 at the wheels.