DarkHorse

Posted on a local board - guy runs a dyno shop and is coming up with these numbers:

"Well then there wrong I guess because thats not how it works out on any of the dyno sheets I just went thru. I went thru 6 from other shops and 10 from here and some were close but none were right according to those formulas.

Correct me if Im wrong but here is one example.

The dyno sheet reads
443.45 max H.p. @ 6000 rpm
458.67 max tq. @ 3800 rpm
and they cross @ 5252

H.P. would equal (458.67 X 3800) / 5252 so that is 331.86

TQ. would equal (443.45 / 6000) X 5252 so that is 388.16

So how is that correct ?"

Here's the formula we posted - disputing his numbers that he got 415hp@3300 rpm and 500.90tq @3300

HP = (TQ X RPM) / 5252

TQ = (HP / RPM) * 5252

Do I have the formula wrong - or is there something that could skew his numbers, making the formula incorrect?

Injuneer

There's nothing wrong with the formula or your numbers. You just forgot to label the results.

At 6,000rpm, the engine was making 388.16 lb-ft.

(388.16 lb-ft X 6000) / 5252 = 443.45HP

At 3,800rpm, the engine was making 458.67 lb-ft

(458.67 lb-ft X 3800) / 5252 = 331.86 HP

Where is the inconsistancy?

Or maybe I don't understand your question.... where did the 3,300rpm come from?

DarkHorse

He was claiming this here Fred - and thanks for the help!

415hp@3300 rpm and 500.90tq @3300

Silver

subscribing

Injuneer

You sure its not typo, and he meant 315 HP?.....

(500.90 lb-ft x 3300) / 5252 = 314.73HP

DarkHorse

That's exactly what we tried to tell him - but he insisted that the "formula" that we were using was only an estimate and he didn't care whether we believed him or not. Needless to say - that's a dyno that my car will never run on.

OldSStroker

I've heard of "happy dynos", but this is a "happy" dyno operator. I'll bet he has a lot of "500" rwhp bolt on cars, too.

Caveat emptor applies. If I partonized that shop it would be caveat venditor!