What does everyone use for driveline efficiency. I got my car dynoed and they used 85%. My numbers came out high and I have the program and am able to change the effeciency.

 

20% loss for an auto, or in your case, 15% for an M6. If you #'s seem high, maybe you got a freak

Nate

 

Thanks for the reply. I am trying to figure out what numbers to change in the program . It has a place to put tire loss too. Ill put the 15% in. Thanks

 

if your losing 20% with a 4L60E and 15% with a T56 with the stock 10 bolt rear behind either, your running the parking brake or have almost flat tires.

 

MTI uses 18% for A4, 15% for M6

just divide your RWHP by .82 for A4, .85 for M6

I have just around 378hp/391tq crank

 

20% A4 and 15% M6 is what I hear also...

 

I put the numbers in and it came out to 330 rwhp and 360 ft/lbs torque. I have no idea why they are so high. The torque seems really high. The car is almost stock.

 

actually I have heard more like 12% for M6 and 15% for auto. and thats from most everyone at LS1.com.

Fact is that no one has yet to pull a motor and dyno it then have a chassis dyno done.
If I had both machines I prolly would of done it by now just to know.. its so irritating. I am sorry but if you are putting down 310 rwhp you do not have a 370hp at the crank motor..

Think of the ZO6.. it has 400 hp and puts down 345-355 on average. and it has more loss since it has IRS (transaxle)..

so, no 15%-20% is a bit off IMO..

Using your .85 method I would have 371.64 hp at the crank.. HARDLY!

But if you use 10% I would have 351 which is much more reasonable.

 

Thanks for the reply. I think that does sound better. Ill try changing the driveline efficiency to 90% and see what the numbers come out too. If that doesnt work Ill just have to see what it does at the track this year. I ran a 13.5 at 107 last year. I have the ftra and am going to have the texas lid this year. I should be able to run alot better this year. I am going to unhook the front sway bar and I can adjust the preload on my from springs so I am going to loosen them up to make it transfer the weight better.

 

i would say it is about 12 to 13% for a M6 car with 16 inch wheels and 13 to 14% for one with 17's. for the A4 i'd say 15 to 17 (depending on t.c.) for 16 inch wheels and 16 to 18 for one with 17's. this is something that goes from driveshaft weight, to tire compound and size, to brake drag and rotor weight, gear ratio, torque converter choice, etc. even having a higher pressure running through the trans can effect drag just as oil weight effects flywheel hp in dyno testing. many, many variables, more than just what you've heard.