thoughts on dyno numbers

[camaro427-69]

i had my first dyno run with my camaro today. it was a brand new 4wheel drive dyno. so they strapped it onto and the guy did the 2 pulls. the engine is a full aluminum merlin-x 540cui, 10.7CR, brodix bb2-x heads with 320cc runners, comp-cams 11-771-8 solid roller cam. desktop dyno and comps cams software both came up with around 680-700 hp/ft-lbs on the engine. i knew that software and real life differs but my dyno run came up with 458HP flywheel and 436HP at the wheels. torque was @500ft-lbs. it has a tremec 5speed with a dual disc clutch. the torque curve jumps up at 1900rpm and is nice and flat but the hp curve falls off from 5400rpm. any thoughts on it? is that just what you have to expect from 40 year old junk or is something way off? my buddy did a run with his 500cui stroker roadrunner and he was even 100hp/60ft-lbs lower than i have been. i just checked timing and jetting (have a equus timing light and a fast dual wideband A/F meter) haven´t checked for compression lately. engine has around 5000miles on it needs no oil, doesn´t smoke etc. dynorun2012.pdf

thanks,
pat

[camaro427-69]

blue line is torque in Newtonmeter, red line is engine HP and dark red is wheel HP. weird is that i just had around 20HP on loss from drivetrain?!?!?!?!?!

[Sean Cooke]

What kind of Dyno where you using? Was it a mustangsyno or a dynojet?

[camaro427-69]

Would it make a difference?

[AintQik]

Don't sweat the numbers too much. Dynos can be goofy. 436 for that motor sounds very low unless something is wrong with it. The better question is how does it feel? 20HP drivetrain loss is also not exactly right. I think you got a bum dyno guy. Try another one.

[camaro427-69]

i was also asking grumpyvette in chevytalk and he was pointing to a restriction intake or exhaust side. need to get another dyno somewhere but it´s hard to find here with someone who really knows detroid iron. the dyno we had was a trailer type but it was accurate cause we had a couple cars like audi rs4 or vw golf gti stock type who made numbers close to manufacturer specs. gonna do some search for a real dyno with tools to check all parameters and from there i can work it out.

[MuscleRodz]

Different dynos read different ways and output different numbers. I know of two local Mustang dynos that read 50hp difference on the same car, same day. software hp does not always account for exhaust restrictions, temp, humidity, and that number is probably before accessory drive hp loss as well. I would not put much stock into the actual numbers.