Dyno
Safety Car
Joined: Oct 2004
Posts: 3,924
Likes: 735
From: Youngstown Ohio
Desktop Dyno's accuracy depends on the accuracy of the info you put in. I use it and always come within 5% of its predictions. You can tailor it by taking a known engine's HP and TQ (actual values, not advertised), and enter all known info.....actual head flow cfm, carb cfm, cam specs, etc., and compare DD's results to the real engine. You may have to use slightly different opinions for "large headers" and subjective judgement calls....changing a manifold could make a 50 hp difference. If you can then closely match your virtual engine with the real one, use those guidelines for future programs.
Le Mans Master
Joined: Apr 2007
Posts: 7,353
Likes: 72
From: Graceland in a Not Correctly Restored Stingray
All computer sims are "garbage in / garbage out", but if you really want something a bit more sophisticated than run of the mill speed shop shoftware and don't mind spending several hundred dollars you might look into Dynomation Advanced or Engine Analyzer Pro (Perf Trends). I have the latter, and IMCO it is certainly NOT geared towards the mere enthusiast. Does that sound like somehing you might be looking for?
Le Mans Master
Joined: Feb 1999
Posts: 8,351
Likes: 75
From: Tampa Bay FL
Dyno software doesn't take into account tuning of carb or ignition. Both can contribute 20%-30% more power when tuned as part of a live dyno session. I spent $175 to have a tuner increase HP by 40 by just laying down a really good advance curve. Then, Lars rebuilt my carb to suite my engine configuration. After all of my engine changes and a few dyno sessions (it helps to have a corvetteforum group that can contribute to a 'test & tune' at the local tuner), I was able to increase rwhp from 140 to 225 and rwtq from about 230 to 289. Not bad for what was an L48 with 190hp at the crank to begin with. Essentially, with all of my mods, I gained close to 100hp/100tq.
Headers
duals/h-pipe
Federal Mogul flat-tops with valve reliefs (hyper)
Accel Perf Distributor with custom curve
Rebuilt OEM ram-air system
Crane Energizer cam (.454/.454, 112 deg lobe sep)
DART Iron Eagle cyl heads
Lars-rebuilt qjet
Edelbrock Performer intake
Hasting Moly Rings
Cloyes True Roller timing set
Rebuilt/Replaced vacuum systems
Dynomax Super Turbo Mufflers
Headers
duals/h-pipe
Federal Mogul flat-tops with valve reliefs (hyper)
Accel Perf Distributor with custom curve
Rebuilt OEM ram-air system
Crane Energizer cam (.454/.454, 112 deg lobe sep)
DART Iron Eagle cyl heads
Lars-rebuilt qjet
Edelbrock Performer intake
Hasting Moly Rings
Cloyes True Roller timing set
Rebuilt/Replaced vacuum systems
Dynomax Super Turbo Mufflers
