So the 565-575HP is measured using the HiPerf motor industry standard HP rating (60*F ambient air temperature) and the 538-556HP using the SAE rating system (77*F ambient air temperature) ?

I can not comment on the specific < 565 -575cshp ratings you noted. However it is true that the same raw dyno HP test results will net a higher hp rating when interpreted per the HiPerf motor industry standard HP rating (60*F ambient air temperature) than when interpreted per the SAE rating system used by the automobile (OEM) manufacturers (77*F ambient air temperature). There is an OSO.COM thread that discusses this in great detail.

Quoting RMBUILDER:

STD J607
J607 standard 60°F / 0% humidity / barometric pressure of 29.92 in-Hg

SAE J1349
SAE J1349 standard of 77°F (25°C) / 0% humidity / barometric pressure of 29.234 in-Hg (99 KPa).

The J607 rates 4-5% higher than J1349 due to a compensation for motoring friction loss.

So the 525 makes around 570 hp when compared to the way most of us have stuff dynoed with the lower sae temp rating,that is impressive. I did wonder how it went from the 535-540 most people talk about it making (which is also impressive for what it is) to the higher numbers. Either way,it makes good numbers,too bad its so much money,Smitty

Even more impressive on 87 octane.

Those numbers are pretty high. I went back to look at my numbers, we've dyno'd a few of them. My sheet shows 544hp @ 5185, 572 trq @ 4674. SAE trq was 547.6 and SAE HP was 519.9.

Thanks,
Dustin

Dustin,

Which SAE J spec ?

Thanks,

Bill

I was dicussing this thread with my engine builder today, and he also has dyno'd some 525's and said what he's seen is around 540hp.

Is that STD J607 or SAE J1349 rating?

My appologies to all. I missunderstood what I was told. Per the dyno lab a new HP525EFI will test 540-555cshp per STD J607. After being subjected to a couple of races the engine will loosen up and will generally produce 565 - 575cshp. Again my appologies.