[ERA Chas]

Pat-you're exercising your court room skills in yet another academic argument of misguided consequence. I know you could just as easily defend the exact opposite argument if you chose to. Yet another display of intelligence is not needed.
The current state of the engine art simply operates on the knowledge that Brent explained. On anything other than purpose-built race engines (which are always dynoed with their race headers because they are integral to the tune) it is a given that the flywheel power gauges the engine's exact current power levels, at this particular tune and parts. RWHP is the more accurate gauge for what you're ranting about-the whole car's power levels in use.

So you sent your pipes out to the dyno, got your number, then put it in the car. Had you gone to the CHASSIS dyno, you promptly would have seen 17 or so percent less than your engine's number. What did that tell you? Of what value was your engine's power minus car?

In my case, after machining and assembly, my combination dynoed 550HP. I used 1 7/8" Galaxy Hookers with 10" collector on the dyno because the operator had no FE headers. The ERA uses 2" primaries. So what was my number? Maybe a bit more. But a year later, when Stainless developed the larger ID sidepipe, Lou sent them them to me to test. I went to the chassis dyno. The new sidepipes produced 49 more HP more than the original set (the prototype pipes from Stainless Specialties) and 5HP less than the open ERA primaries with collector. The peak was 462 RWHP and the math says that's 16% less for drive train loss. It correlates. THAT's the only other accurate way to know an academic number. But the original dyno testing told me I had a sound tune that was a stout street engine in 1991.

Brent and the builders test to optimize their parts selection, refine the fuel and ignition curves and observe the integrity of the build (leaks or porosity).

I watched 30 engines a month get assembled and dynoed. They spanned the major categories from SBC to Hemi and everything in between (except FE's). They were all dynoed with the same headers for their brand. As an example, the SBF's from 300HP to 708HP all got either of 2 headers. They differed by diameter and collector length. The sheets went to the customer with the engine. In rare cases a customer would send his headers because it was a specific race engine and he wanted us to optimize the combination around his headers. His 'chassis dyno' was his timeslips-which is the ONLY accurate way to determine relative power levels.

Begging all those points about wanting to know power at 1800RPM, the gas quality in Athens, the load factor of the brake, the humidity difference from A to B and such is not what engine dynos are for. A guy who uses that tool every day and explains that should not be persecuted to defend his methods. He knows the exact purpose of that dyno and uses it as such. That's why street-engine guys are often a huge pain in the ass to professionals. If you have years of time slips, lap times and changes in your resume, maybe then offer your differing point of view. Makes for good discussion when it comes from personal or professional experience.

Look we're lucky enough to have a few professionals who come on here and have the patience and donate their time (AND THEIR KNOWLEDGE BASE GATHERED OVER DECADES). They EDUCATE us-why not try to learn and not bicker with them about internet-mined 'facts'?? I'd love to have more of them but they have livings to make. Brent is currently the most generous that way. Sure, it's a way to generate business-that's as it should be for what he contributes. Plus, he's a mechanical engineer, he doesn't just pull this stuff out of his ass!

Let's don't drive him away by being dic-head street weenies with pendantic, debating-class arguments and always try to exhibit sophistication in his field of experience.

I for one, prefer to learn and question what I don't understand, not challenge.