First Time on Dyno!

[JR]

Wheel Dyno's can be an excellent Tuning tool.
That said,
it would appear from most threads I've seen on this Site, that every time someone/anyone goes to a Chassis/wheel Dyno and posts the results ? The ensuing conversation then gets fixated on trying to then back-calculate Engine Flywheel Horsepower / Trq ?..... from the Chassis/Wheel numbers recorded.

Why is that ?
You will never know actual Engine/Flywheel HP/Trq because you were NOT measuring Engine/Flywheel power ?

If it makes 385 hp at the wheels and it runs great, be happy  

I agree. I could really care less what crank HP is.

Unless you're planning to swap the engine into multiple different vehicles, or maybe plan on swapping transmssions or axles, crank HP seems like a totally irrelevant number (to me.)

[c00nhunterjoe]

I like to dyno the engine before install. Its nice to break them in on the dyno, then do a baseline tune prior to install. That way you know its set and ready to go and any potential problems are found are repaired prior to installing in a car.

[RECHRGD]

How about 385x1.3=500......

He lost 30 % of original HP
Not gain 30 % of rear wheel HP

Actually, that result is probably closer to reality than the others.  You're looking for a unknown crank hp from a known rwhp. 

[c00nhunterjoe]

Still think he is looking more at 475. Time to hit the 1320 and post the slips!

[70sixpkrt]

When I first built my motor, it did 498 and 535 tq on an engine dyno. A few years later, I put it on a chassis dyno. I did 399hp with 448 tq and it was running rich. The guy who did the dyno said my car would lose approximately 17% thru the drivetrain since it was a 4 speed. I ran down the strip and did 13.01 at 108 mph. 60 foot time and traction sucked. I really don't think you would lose 30%.

[Kern Dog]

My 440/493 with 10.8 compression and a '509 cam made 369 to the wheels with UNported Edelbrock heads, 2" headers and a Demon 850 4 barrel. I was disappointed too with the numbers. We have all grown up with the "gross HP" advertised numbers so these net numbers are a bit of a kick to the dick.

[rollo1504]

Indeed. Major brain fart.

[c00nhunterjoe]

It happens.

[6pkrtse]

First time on a Dynamometer is always fun. Yes, there are a lot of individual engine shops out there that can pad the #'s by playing with the interia factors on the dyno to make the customer happy. We have 42 individual different dyno rooms at work & ours have to be all OEM calibrated to read "true" numbers. So, if a guy makes 600 at our shop, he could possibly make 640 to 680 or more at another shop & not know the difference.

Here is when we did my Hemi.

https://www.facebook.com/193108010854372/videos/652818031550032/?t=0