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01-10-2006, 11:10 AM | #1 | ||
Turbo Falcon Fiend
Join Date: May 2005
Location: Far West NSW
Posts: 3,213
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Hi Folks,
As the title says, does anyone have any tips for deducing an approximate value for flywheel power from rear wheel power? My car has made 162rwkw on a dyno. If I allow for the automatic trans, the differential and any other sources of friction, drag, heat etc..... What would an approximate value be for flywheel kilowatts?
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01-10-2006, 11:32 AM | #2 | ||
FF.Com.Au Hardcore
Join Date: Dec 2004
Location: Canberra Region
Posts: 8,977
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About 210-220kw. All dynos are different and so are the operators so theres never an accurate figure that can be agreed apon.
But a generally accepted figure is to multiply the rwkw by 1.3 or so to get you flywheel power. A better guide is actually a 1/4mile, in particular the mph.
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2016 FGX XR8 Sprint, 6speed manual, Kinetic Blue #170 2004 BA wagon RTV project. 1998 EL XR8, Auto, Hot Chilli Red 1993 ED XR6, 5speed, Polynesian Green. 1 of 329. Retired 1968 XT Falcon 500 wagon, 3 on the tree, 3.6L. Patina project. |
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01-10-2006, 11:44 AM | #3 | ||
FF.Com.Au Hardcore
Join Date: Feb 2005
Location: Pit Lane
Posts: 11,867
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I have been told by a guy that owns a engine dyno as well as a chassis dyno, the difference on a late model car is about 22%
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01-10-2006, 09:11 PM | #4 | ||
Turbine Power
Join Date: Feb 2005
Location: Wagga Wagga
Posts: 120
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it tends to work out that rear wheel HP equars Flywheel KW. Not gospel but a good guide.
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01-10-2006, 11:03 PM | #5 | ||
LPG > You
Join Date: Dec 2004
Location: Sydney, NSW, Australia
Posts: 4,277
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It isn't possible to calculate that accurately. Or anything approaching accurate.
The most general guide would be 18-20% loss manual, 20-22% loss auto, RWD. However, DynoDynamics Dynamometers (and in general, dynos & operators in this country) don't follow this, as they have silly software that adjusts the readings to what it believes (or is programmed to believe) is correct. That's a pretty poor system, there should never be any correction factor, especially attempting to "adjust" for variables like humidity, air temp, traction.. yadda yadda yadda. PS- I'm well aware people will attempt to flame me for the above post, and I'm well prepared for it.
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01-10-2006, 11:11 PM | #6 | |||
LPG > You
Join Date: Dec 2004
Location: Sydney, NSW, Australia
Posts: 4,277
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Quote:
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02-10-2006, 12:25 AM | #7 | ||
Only a matter of time.
Join Date: Apr 2006
Location: Melbourne
Posts: 1,127
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I just go 25%
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02-10-2006, 02:27 AM | #8 | ||
torque is your friend
Join Date: Jan 2005
Posts: 667
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This has been discussed heaps of times before. You CAN'T calculate drive train loss across the board using a % figure. Each drivetrain will have a fixed kw loss regardless of what engine is powering it. A 25% loss of a 180fwkw engine is 45kw through the drivetrain. Turbocharge that same engine to get a 300fwkw figure and apply the same 25% loss theory and you have a 75kw loss through the very same drivetrain. Impossible.
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02-10-2006, 03:25 AM | #9 | |||
FF.Com.Au Hardcore
Join Date: Dec 2004
Location: Canberra Region
Posts: 8,977
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Quote:
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2016 FGX XR8 Sprint, 6speed manual, Kinetic Blue #170 2004 BA wagon RTV project. 1998 EL XR8, Auto, Hot Chilli Red 1993 ED XR6, 5speed, Polynesian Green. 1 of 329. Retired 1968 XT Falcon 500 wagon, 3 on the tree, 3.6L. Patina project. |
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02-10-2006, 05:03 AM | #10 | ||
Only a matter of time.
Join Date: Apr 2006
Location: Melbourne
Posts: 1,127
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Theres a fraction to much friction
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02-10-2006, 06:02 PM | #11 | |||
Bring on the lion...
Join Date: Nov 2005
Posts: 974
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Quote:
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El falcon, 4.0, XR6 camshaft, pacemaker extractors, 2.5 inch exhaust with tri flow sports muffler, AU TE50 intake, with K&N panel filter, Advanti racing Stalker 17" rims, Sitting on Ultra Low King Springs, 'Gabriel' Ultras Lowered struts, NOW MANUAL, 3.45 LSD 9.694 @ 75.38 MPH at Mildura Drag Strip 1/8 Mile XC Falcon project car underway...... |
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02-10-2006, 08:50 PM | #12 | |||
torque is your friend
Join Date: Jan 2005
Posts: 667
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Quote:
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03-10-2006, 07:32 AM | #13 | |||
Weezland
Join Date: Aug 2005
Location: Sydney,workshop mod
Posts: 7,216
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We still get varying numbers from one time to another,the biggest difference highest to lowest was over 60hp. I dont put much faith in em,just tune the car and thats it. Although they can give a rough guide.. |
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03-10-2006, 10:24 AM | #14 | |||
LPG > You
Join Date: Dec 2004
Location: Sydney, NSW, Australia
Posts: 4,277
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Quote:
The best guide to know how well your car's performing is to take it to the track and give it a run. If you really want to know how much power your engine has (and can afford it), take it out and send it to a proper engine dyno. Power figures from chassis dyno's are close to useless. Ask any 1000rwhp Supra owner from the US who runs 12.5 @ 135mph about it.... :
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