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#1
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Chassis dyno vs engine dyno
Chassis dyno vs engine dyno , how much is lost to the rear wheels on chassis dyno vs engine dyno . Torque & HP.
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#2
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If interested there is lot's of opinions on 'Google' regarding Chassis dyno Confusion....
http://www.badasscars.com/index.cfm/...d=64/prd64.htm http://www.onallcylinders.com/2012/0...u-should-know/ Also what type of chassis dyno makes a difference. And a discussion here: https://forums.maxperformanceinc.com...t=chassis+dyno https://forums.maxperformanceinc.com...t=chassis+dyno .
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'70 TA / 505 cid / same engine but revised ( previous best 10.63 at 127.05 ) Old information here: http://www.hotrod.com/articles/0712p...tiac-trans-am/ Sponsor of the world's fastest Pontiac powered Ford Fairmont (engine) 5.14 at 140 mph (1/8 mile) , true 10.5 tire, stock type suspension https://www.youtube.com/watch?v=qDoJnIP3HgE |
#3
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Quote:
Stan
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Stan Weiss/World Wide Enterprises Offering Performance Software Since 1987 http://www.magneticlynx.com/carfor/carfor.htm David Vizard & Stan Weiss' IOP / Flow / Induction Optimization - Cam Selection Software http://www.magneticlynx.com/DV Download FREE 14 Trial IOP / Flow Software http://www.magneticlynx.com/DV/Flow_..._Day_Trial.php Pontiac Pump Gas List http://www.magneticlynx.com/carfor/pont_gas.htm Using PMD Block and Heads List http://www.magneticlynx.com/carfor/pont_pmd.htm |
#4
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How long is this piece of imaginary string I'm not holding? Without any details you can't even guess approximates.
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#5
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461 muncie S-60 rear 354 gears chassis #s @ rear wheels 424HP & 484TQ.
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#6
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A WAG 500 HP and 570 Torque
Stan
__________________
Stan Weiss/World Wide Enterprises Offering Performance Software Since 1987 http://www.magneticlynx.com/carfor/carfor.htm David Vizard & Stan Weiss' IOP / Flow / Induction Optimization - Cam Selection Software http://www.magneticlynx.com/DV Download FREE 14 Trial IOP / Flow Software http://www.magneticlynx.com/DV/Flow_..._Day_Trial.php Pontiac Pump Gas List http://www.magneticlynx.com/carfor/pont_gas.htm Using PMD Block and Heads List http://www.magneticlynx.com/carfor/pont_pmd.htm |
#7
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Look at the two sets of dyno graphs I've attached.
Same car, same tune, same everything - except torque converters. The first graph has two different converters I was testing. The second graph is another converter, but with a lock-up feature and the test was ran with the converter locked. The locked converter test is more similar to testing a car with a manual transmission. I had another instance to test a motor on an engine dyno, and it made ~550hp at the flywheel. In the car, different headers, full exhaust, air cleaner in place, it put 426 to the wheels on a DynoJet. Recently, I tested my friend's TOTALLY stock '79 Trans Am, 403 2.73 gears, 27,xxx miles. It was rated at 180 or 185hp, which I always assumed to be flywheel (since chassis dynos didn't really exist at the time). On our DynoJet, it put 178 to the wheels. That was through the crappy old pellet catalytic converter. SOOOO many variables. Like Stan stated, a Wild @$$ Guess is about as good as you can do. About as accurate as I can state is the RWHP will be about 20% lower than flywheel - but with a +/- range of up to 18% (2% to 38% of flywheel).
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'73 T/A (clone). Low budget stock headed 8.3:1 455, 222/242 116lsa .443/.435 cam. FAST Sportsman EFI, 315rwhp/385rwtq on 87 octane. 13.12 @103.2, 1.91 60'. '67 Firebird [sold], ; 11.27 @ 119.61, 7.167 @ 96.07, with UD 280/280 (108LSA/ 109 ICL)solid cam. [1.537, 7.233 @93.61, 11.46 @ 115.4 w/ old UD 288/296 108 hydraulic cam] Feb '05 HPP, home-ported "16" D-ports, dished pistons (pump gas only), 3.42 gears, 275/60 DR's, 750DP, T2, full exhaust My webpage http://lnlpd.com/home |
#8
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Just for comparison, on an engine Dyno my combo made 794hp and 697 lbft. Tq.
The mph and ET from the track shows 728.62 flywheel HP and 655.76 rear wheel HP. Your HP computed from your vehicle MPH is 754.50 flywheel HP and 679.05 rear wheel HP. from the Wallace Calculators. I know it's not engine to chassis Dyno. But is a comparison on how much I may be losing through the trans/rear and exhaust. |
#9
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The chassis dyno's don't just see the losses from trans, rear and maybe Exh , but they also see the losses from the mass of your rotating rear tires and that can be a good added percentage of loss when your spinning up a big pair of slicks that can hook up 600 plus hp .
I have never looked to see if anyone has done such, but I would love to see a back to back chassis dyno test of a car with street tires and then a 11 or 14" wide set of slicks.
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Wernher Von Braun warned before his retirement from NASA back in 1972, that the next world war would be against the ETs! And he was not talking about 1/8 or 1/4 mile ETs! 1) 1940s 100% silver 4 cup tea server set. Two dry rotted 14 x 10 Micky Thompson slicks. 1) un-mailed in gift coupon from a 1972 box of corn flakes. Two pairs of brown leather flip flops, never seen more then 2 mph. Education is what your left with once you forget things! |
#10
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There is also the Dynatrac hub dyno, rear wheels removed with adapter bolted to the axle flange.
My 2004 LS1 GTO did 428rwhp/402 rwtq. Being a stick shift, I am guessing around 15 percent drivetrain loss putting it about 500 flywheel hp. I plan to have my '67 455 Firebird out on this dyno someday. |
#11
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i had one chassis dyno gut tell me convertors do make a big difference and slicks that grow also do compared to a radial slick/DOT tire.
I would think gear ratio would affect it as it multiplies torque at the tires. My auto 2004 GTO stock LS1 made 274 on one chassis dyno and 282 on the other one at the shop, factory rated 350 hp.
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Skip Fix 1978 Trans Am original owner 10.99 @ 124 pump gas 455 E heads, NO Bird ever! 1981 Black SE Trans Am stockish 6X 400ci, turbo 301 on a stand 1965 GTO 4 barrel 3 speed project 2004 GTO Pulse Red stock motor computer tune 13.43@103.4 1964 Impala SS 409/470ci 600 HP stroker project 1979 Camaro IAII Edelbrock head 500" 695 HP 10.33@132 3595lbs |
#12
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From my understand of how the chassis dyno and math works. Different rear gear ratios should not change the readings.
Stan
__________________
Stan Weiss/World Wide Enterprises Offering Performance Software Since 1987 http://www.magneticlynx.com/carfor/carfor.htm David Vizard & Stan Weiss' IOP / Flow / Induction Optimization - Cam Selection Software http://www.magneticlynx.com/DV Download FREE 14 Trial IOP / Flow Software http://www.magneticlynx.com/DV/Flow_..._Day_Trial.php Pontiac Pump Gas List http://www.magneticlynx.com/carfor/pont_gas.htm Using PMD Block and Heads List http://www.magneticlynx.com/carfor/pont_pmd.htm |
#13
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On the chassis dyno, I've tested in 2nd gear then in 3rd gear (automatics) and there was very little difference in power readings. So very minimal change with different rear gears.
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'73 T/A (clone). Low budget stock headed 8.3:1 455, 222/242 116lsa .443/.435 cam. FAST Sportsman EFI, 315rwhp/385rwtq on 87 octane. 13.12 @103.2, 1.91 60'. '67 Firebird [sold], ; 11.27 @ 119.61, 7.167 @ 96.07, with UD 280/280 (108LSA/ 109 ICL)solid cam. [1.537, 7.233 @93.61, 11.46 @ 115.4 w/ old UD 288/296 108 hydraulic cam] Feb '05 HPP, home-ported "16" D-ports, dished pistons (pump gas only), 3.42 gears, 275/60 DR's, 750DP, T2, full exhaust My webpage http://lnlpd.com/home |
#14
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Quote:
Your 18% Trans/Chassis/Tire loss number is "SPOT ON" vs what Ford has used for many years (and verified yearly on the Company Test Tracks). Tom V.
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"Engineers do stuff for reasons" Tom Vaught Despite small distractions, there are those who will go Forward, Learning, Sharing Knowledge, Doing what they can to help others move forward. |
#15
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Quote:
Then it was love at first sight!
__________________
'73 T/A (clone). Low budget stock headed 8.3:1 455, 222/242 116lsa .443/.435 cam. FAST Sportsman EFI, 315rwhp/385rwtq on 87 octane. 13.12 @103.2, 1.91 60'. '67 Firebird [sold], ; 11.27 @ 119.61, 7.167 @ 96.07, with UD 280/280 (108LSA/ 109 ICL)solid cam. [1.537, 7.233 @93.61, 11.46 @ 115.4 w/ old UD 288/296 108 hydraulic cam] Feb '05 HPP, home-ported "16" D-ports, dished pistons (pump gas only), 3.42 gears, 275/60 DR's, 750DP, T2, full exhaust My webpage http://lnlpd.com/home |
#16
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I ran mine on a chassis dyno a few months ago and got 516 hp and 543 tq
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