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Re: Flat HP Curve
[Re: INTMD8]
#2987490
11/21/21 12:47 PM
11/21/21 12:47 PM
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Joined: Jan 2003
Posts: 14,545
So. Burlington, Vt.
fast68plymouth
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 14,545
So. Burlington, Vt.
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Let’s say you built a run of 5 engines all exactly the same, or bought them...... like Crate engines.
If you dyno tested them all back to back on the same dyno, the power curves and output should be very close.
Now take those 5 engines and stick them in 5 different cars with different transmissions, gears, converters, exhaust systems etc, and test the 5 different vehicles on the same chassis dyno.
I’m confident the chassis dyno results would be way different from each other than the 5 engine dyno tests.
If you’re really trying to determine what the power curve and output of the “engine” is........ put it on an engine dyno.
68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123
Dealer for Comp Cams/Indy Heads
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Re: Flat HP Curve
[Re: INTMD8]
#2987496
11/21/21 12:57 PM
11/21/21 12:57 PM
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Joined: Feb 2008
Posts: 730
Central TEXAS!!!!
sr4440
super stock
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super stock
Joined: Feb 2008
Posts: 730
Central TEXAS!!!!
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horsepower is a calculated value, The dyno measures torque, the engine rpm is then used in the calculation Horsepower (HP) = (Torque × Speed)/5252, if the dyno computer does not have the real engine rpm the readings are not correct. I used a Mustang dyno for several years, they either were too lazy or did not have the proper equipment to read engine rpm. The old roller rpm trick is when you can not get a real engine rpm number. Mustang used to use what was called smart tach, and it was sometimes a challenge to get a proper rpm reading, as a regular distributor, MSD, coil on plug, waste spark, etc. all have different settings in the soft ware to condition the signal. If the vehicle has a manual transmission and you stick it in 1 to 1 ration usually 4th gear it is close, but an automatic especially with a loose converter, wasting your time. Depends on the dyno. Dynojet measures horsepower and calculates torque if it has an rpm input. Otherwise you just get horsepower vs speed. Are you sure you don't have that backwards? Because the rollers on a Dynojet absorbs torque. Torque is a measured output (from a strain gauge) and you need a rpm value to calculate horsepower. Joe
Without Data, you’re just another guy with an opinion.
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Re: Flat HP Curve
[Re: sr4440]
#2987512
11/21/21 01:47 PM
11/21/21 01:47 PM
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Joined: May 2019
Posts: 726
Lake Villa Il
INTMD8
super stock
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super stock
Joined: May 2019
Posts: 726
Lake Villa Il
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Yeah I'm sure.
What you described is not how a dynojet works, if we are talking inertia and not eddy current.
Last edited by INTMD8; 11/21/21 01:47 PM.
69 Charger. 438ci Gen2 hemi. Flex fuel. Holley HP efi. 650rwhp @7250 510rwtq @5700
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Re: Flat HP Curve
[Re: INTMD8]
#2987518
11/21/21 01:55 PM
11/21/21 01:55 PM
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Joined: Jan 2003
Posts: 8,245
Plymouth, MI
Blusmbl
master
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master
Joined: Jan 2003
Posts: 8,245
Plymouth, MI
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Yeah I'm sure.
What you described is not how a dynojet works, if we are talking inertia and not eddy current.
x2. Inertia dynos measure HP and then back calculate torque with an rpm signal. Eddy current dynos measure torque.
'18 Ford Raptor, random motorcycles, 1968 Plymouth Fury III - 11.37 @ 118
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Re: Flat HP Curve
[Re: Blusmbl]
#2987560
11/21/21 03:39 PM
11/21/21 03:39 PM
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Joined: Aug 2003
Posts: 43,913
Bend,OR USA
Cab_Burge
I Win
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I Win
Joined: Aug 2003
Posts: 43,913
Bend,OR USA
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Last edited by Cab_Burge; 11/21/21 09:52 PM.
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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Re: Flat HP Curve
[Re: Blusmbl]
#2987644
11/21/21 08:39 PM
11/21/21 08:39 PM
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Joined: Feb 2008
Posts: 730
Central TEXAS!!!!
sr4440
super stock
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super stock
Joined: Feb 2008
Posts: 730
Central TEXAS!!!!
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Yeah I'm sure.
What you described is not how a dynojet works, if we are talking inertia and not eddy current.
x2. Inertia dynos measure HP and then back calculate torque with an rpm signal. Eddy current dynos measure torque. I stand corrected, you both are correct, the dynojet measures work (hp) then can calculate torque with a rpm signal. Joe
Without Data, you’re just another guy with an opinion.
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