DESKTOP DYNO QUESTION
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Logistics Pro
Joined: Jan 2011
Posts: 4,762
Likes: 54
From: Antelope Valley ,CA
DESKTOP DYNO QUESTION
I just got desktop dyno 5 sim
is this even close to being close ?
to me it seems to err to the high side and the bigger the carb cfm i go the higher the hp and torq ,
i put in my specs (moderate build )
390 stock bore
10:1 flatop pistons
lunati 62001 cam kit
heads have stock valves and pocket porting
edelbrock performer manifold
holley 600cfm dbl pmper
small tube headers
i'll post a snip of chart later
is this even close to being close ?
to me it seems to err to the high side and the bigger the carb cfm i go the higher the hp and torq ,
i put in my specs (moderate build )
390 stock bore
10:1 flatop pistons
lunati 62001 cam kit
heads have stock valves and pocket porting
edelbrock performer manifold
holley 600cfm dbl pmper
small tube headers
i'll post a snip of chart later
Fleet Mechanic
Joined: Nov 2010
Posts: 1,501
Likes: 1
From: Axtell, TX
Yeah I'd say it's pretty generous with the numbers. 511tq?! maybe with a 4.25" crank. In Jays book when he ran the Performer on the 445 mule he got a max tq of 505ft/lbs. That's with more cam and heads too.
I'd say take 85-90% of those values as a ballpark figure. 300-320hp 435-460ft/lbs.
I don't know if you're on the other forum or not but you could check your numbers against Werby's Gonkulator. His figures are the closest thing to a dyno you can get. If you find a semi-reliable margin of error between the two, you could nail down future results better.
Lastly.....think you could run the numbers on mine?
Specs are in my garage. 2" primary headers open pipe.
I'd say take 85-90% of those values as a ballpark figure. 300-320hp 435-460ft/lbs.
I don't know if you're on the other forum or not but you could check your numbers against Werby's Gonkulator. His figures are the closest thing to a dyno you can get. If you find a semi-reliable margin of error between the two, you could nail down future results better.
Lastly.....think you could run the numbers on mine?
Specs are in my garage. 2" primary headers open pipe.
Laughing Gas
Joined: Aug 2008
Posts: 840
Likes: 8
Back when I was selecting a cam for a mild performance build, I called the Crane Tech Line for some cam selection advice. After we decided on a cam, the fellow I spoke to asked for all my engine and carb details and ran some sort of computer program to determine the flywheel Hp.
He got 480 Hp. I suspect this was high too and I'd probably be around 425 Hp based on known similiar engines.
My thoughts on this are the computer program expects perfect ignition timing and perfect fuel mixture. In the real world, these two expectations are probably optimistic.
Just speculation on my part, but I'll stick with that for now as it offers a plausible explanation.
He got 480 Hp. I suspect this was high too and I'd probably be around 425 Hp based on known similiar engines.
My thoughts on this are the computer program expects perfect ignition timing and perfect fuel mixture. In the real world, these two expectations are probably optimistic.
Just speculation on my part, but I'll stick with that for now as it offers a plausible explanation.
FTE Leadership Emeritus
Joined: Jul 2002
Posts: 42,561
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From: Long Island USA
Also, I'm wondering if they take friction into account. Rings in the cylinder, pistons rubbing the cylinder, bearings, oil pumping losses, the effort to pull air into the cylinders, the effort to push the exhaust OUT of the cylinders, all that takes it's toll.
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Logistics Pro
Joined: Jan 2011
Posts: 4,762
Likes: 54
From: Antelope Valley ,CA
YEAH i figured it was off and just a calculated guess , i corrected some of the obvious mistakes
they had ambient temp at 68f i changed it to 80f
i just got it let me play with it and get use to the software
yes sleepy i'll run your numbers i'll post in next couple days
they had ambient temp at 68f i changed it to 80f
i just got it let me play with it and get use to the software
yes sleepy i'll run your numbers i'll post in next couple days
Thread Starter
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Logistics Pro
Joined: Jan 2011
Posts: 4,762
Likes: 54
From: Antelope Valley ,CA
sleepy what's your guess on c/r for your engine ? also do have a cam card for the cam ? when i entered all my specs off card numbers changed alot .
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Cranky Old Guy
Joined: Mar 2008
Posts: 3,562
Likes: 6
From: Raphine, Virginia
Yeah, without all the correct data it's a crap shoot. I do use mine to see what difference changing a part makes, but other than that, put no faith in the numbers. Even real engine dyno's vary greatly. Only true test is a chassis dyno which really crushes ego's.
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Fleet Mechanic
Joined: Jun 2007
Posts: 1,931
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From: Ohio
I just got desktop dyno 5 sim
is this even close to being close ?
to me it seems to err to the high side and the bigger the carb cfm i go the higher the hp and torq ,
i put in my specs (moderate build )
390 stock bore
10:1 flatop pistons
lunati 62001 cam kit
heads have stock valves and pocket porting
edelbrock performer manifold
holley 600cfm dbl pmper
small tube headers
i'll post a snip of chart later
is this even close to being close ?
to me it seems to err to the high side and the bigger the carb cfm i go the higher the hp and torq ,
i put in my specs (moderate build )
390 stock bore
10:1 flatop pistons
lunati 62001 cam kit
heads have stock valves and pocket porting
edelbrock performer manifold
holley 600cfm dbl pmper
small tube headers
i'll post a snip of chart later
Fleet Mechanic
Joined: Nov 2010
Posts: 1,501
Likes: 1
From: Axtell, TX
Should have all the info you need. I know about what it makes so it'll be interesting to see the difference. Thanks!
Hotshot
Joined: Apr 2009
Posts: 14,333
Likes: 247
From: Stanley, VA
All of this is called "parasitic power loss" that's best defined as horsepower that the engine makes but never makes it out the crankshaft. If you want to see a HUGE parasitic power loss, put a roots style (GMC) blower on an engine.
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Logistics Pro
Joined: Jan 2011
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From: Antelope Valley ,CA
VIDEO
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Logistics Pro
Joined: Jan 2011
Posts: 4,762
Likes: 54
From: Antelope Valley ,CA
since video i added a hei distributor , revvs alot faster i think curv of new dizzy is alot better still have to check what spings are in it maybe go lighter springs