Confusing desktop dyno numbers.
I was playing around with the valve lift on desktop dyno with my engine, seeing what the difference between 1.5 and 1.6 rockers would be.
My cam is 236 in 242 ex/ .520 in .540 ex/ 110LSA with the 1.5 rockers. Changing the exhaust rockers to 1.6 (increasing the valve lift to .576) I gain 6 hp at peak rpm, but when I change the intake rockers to the 1.6 (increasing valve lift to .555) the peak hp goes down 2 hp. What's the verdict? Am I maxing out the potential of my AFR 195 heads? Or should I not trust the software? |
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I don't the answer. :huh: Out of curiosity, how accurate is your desktop to real number? I'm curious to know where it'd put me at. |
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And the peak rpm points are not accurate. Probably because it doesn't take into account the weight of the reciprocating assembly and valve float. So I just go by what the numbers are where I know my engine actually peaks out, at around 6K. And it's much more accurate that way. I can send it to you if you want... |
Wow, if I go with the 1.65 instead of the 1.6, my valve lift will go from .520/ .540 to .576/ .594. :thumbs_up:
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Make sure your springs are rated for the new valve lift.
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The springs are ok for up to .6 lift. How much fuel economy do you think you'll gain with that cam?
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With less than 10 degree change in duration it is not going to give much better milage. Over the years I found cams with an effect duration of 214* to give the best gas milage to power. This is in a 350 Chevy. Compression is the other milage added. The higher the better. :rolleyes: |
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Also, a friend ran my engine combo for the Chevelle and it was way off and yes he did use the correct flow rates for my Edelbrock Performer RPM heads. Desktop Dyno 2000 showed 737hp@7000 & 650tq@5000. I've run my car on a chassis dyno and it made 461rwhp and 462rwtq. Given a 20% loss that's around 550hp. If you want to run it and see what yours comes up with, here's the info for my engine: Standard bore Chevy 454 12.25:1 compression Heads: Edelbrock Performer RPMs 60559 Flow Intake/Exhaust .100 76/70 .200 146/132 .300 210/156 .400 255/181 .500 294/207 .600 314/228 Comp Cams Solid Roller 11-692-8 .622 lift I/E 246 at .050 I/E 110 Lobe Center 106 Intake Center Specs at .050 IO: 17 EO: 57 IC: 49 EC: 9 Victor Jr Intake Holley 850 built by The Carb Shop (flows 950 cfm) Hooker Competition Headers 3" exhaust with Flowmasters |
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