Re: Chassis dyno numbers: HP loss for 4 sp./Dana?
[Re: 1970mopar]
#369640
07/08/09 01:03 PM
07/08/09 01:03 PM
|
Joined: Jan 2003
Posts: 16,123
Grand Haven, MI
patrick
I Live Here
|
I Live Here
Joined: Jan 2003
Posts: 16,123
Grand Haven, MI
|
I'd swagger somewhere in the 15-20% area....
also, was the engine dyno'd with the same headers, air cleaner, accessory drive (water pump, PS pump if applicable, and alternator), and exhaust system as what's installed in the car? if not, there's some additional losses, too....I'd expect ~450-480 RWHP if your engine simulation was accurate (.8*560=448, .85*560=476)
Last edited by patrick; 07/08/09 01:05 PM.
1976 Spinnaker White Plymouth Duster, /6 A833OD
1986 Silver/Twilight Blue Chrysler 5th Ave HotRod **SOLD!***
2011 Toxic Orange Dodge Charger R/T
2017 Grand Cherokee Overland
2014 Jeep Cherokee Latitude (holy crap, my daughter is driving)
|
|
|
Re: Chassis dyno numbers: HP loss for 4 sp./Dana?
[Re: patrick]
#369642
07/08/09 02:14 PM
07/08/09 02:14 PM
|
Joined: Aug 2003
Posts: 8,716
Baltimore/Denver
64Post
OP
master
|
OP
master
Joined: Aug 2003
Posts: 8,716
Baltimore/Denver
|
Quote:
I'd swagger somewhere in the 15-20% area....
also, was the engine dyno'd with the same headers, air cleaner, accessory drive (water pump, PS pump if applicable, and alternator), and exhaust system as what's installed in the car? if not, there's some additional losses, too....I'd expect ~450-480 RWHP if your engine simulation was accurate (.8*560=448, .85*560=476)
My numbers were from a chassis dyno, not an engine dyno. The engine started to lean out at 4800 rpm, so we shut it down. I fully expect to see 500-510 HP, and 500 TQ to the wheels when I get more fuel and rpm in it -- at least on that dyno. I plan on backing up the initial results on another dyno when I can.
The programs showed I should be in the area of 580HP at the flywheel with this combo, and over 600HP with open headers. So, 85% puts me very near 500 HP. Not bad for a nearly stock appearing "383." 
Last edited by 64Post; 07/08/09 02:15 PM.
|
|
|
Re: Chassis dyno numbers: HP loss for 4 sp./Dana?
[Re: 64Post]
#369643
07/08/09 03:20 PM
07/08/09 03:20 PM
|
Joined: Jan 2003
Posts: 31,060
Oregon
AndyF
I Win
|
I Win
Joined: Jan 2003
Posts: 31,060
Oregon
|
I've spent a lot of time on both engine dynos and chassis dynos testing various big block configurations. My old low deck 470 combo would pull 550 hp on the engine dyno and 475 hp on the chassis dyno. I'd say your numbers look to be in the right ballpark. My combo on the chassis dyno was a Doug Nash 5 speed (tested in 5th gear which is 1:1) and a Dana 60 rearend. High quality radial tires will help with the power numbers as will any weight reduction in the drivetrain. There is just a lot of power lost to drivetrain friction. 
Last edited by AndyF; 07/08/09 03:21 PM.
|
|
|
Re: Chassis dyno numbers: HP loss for 4 sp./Dana?
[Re: AndyF]
#369644
07/08/09 04:42 PM
07/08/09 04:42 PM
|
Joined: Aug 2003
Posts: 8,716
Baltimore/Denver
64Post
OP
master
|
OP
master
Joined: Aug 2003
Posts: 8,716
Baltimore/Denver
|
Quote:
I've spent a lot of time on both engine dynos and chassis dynos testing various big block configurations. My old low deck 470 combo would pull 550 hp on the engine dyno and 475 hp on the chassis dyno. I'd say your numbers look to be in the right ballpark.
My combo on the chassis dyno was a Doug Nash 5 speed (tested in 5th gear which is 1:1) and a Dana 60 rearend. High quality radial tires will help with the power numbers as will any weight reduction in the drivetrain. There is just a lot of power lost to drivetrain friction.
Thanks, Andy. You of all people certainly should have enough empirical data accumulated over the years to make a sound quesstimate.
We made our pulls in 4th gear. I'm with you on the tire advice; I did have decent radials mounted. I have a little axle problem to sort through first... and perhaps a fan shroud is needed as well.
|
|
|
|
|
