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Transmission Losses
http://www.gt4dc.co.uk/forum/viewtopic.php?f=1&t=6379		 Page 1 of 4
Author:  dale [ Fri Mar 08, 2013 2:18 pm ]
Post subject:  Transmission Losses
what was the wheel bhp there? what turbo is it running like?
Author:  Treacle [ Fri Mar 08, 2013 2:28 pm ]
Post subject:  Re: my st185 rebuld hoping for 400bhp maped at 1.6bar and 39
Dale, looking at your sig how in the hell are you running 256bhp at the wheels on a standard CT20 at 1.07bar? Depending on the transmission losses that would be at least 350bhp+ at the flywheel, (probably more like 380bhp) which does not seem possible on a stock turbo at all and especially at that boost level, not even close. Or are you running it in a 2WD car with less transmission losses?
Author:  mixer72 [ Fri Mar 08, 2013 2:50 pm ]
Post subject:  Re: my st185 rebuld hoping for 400bhp maped at 1.6bar and 39
dale wrote:
what was the wheel bhp there? what turbo is it running like?



its a stage 1 s148 ct26 from turbo technic runing at 1.5bar but the boost is playing up so not getting full power, and 218bhp at the wheels

as Treacle says that can not ne wheels power you have as im runing 363bhp and only getting 218bhp at the wheels, and tha stock ct20 will only make 350bhp i know as i have done it and that was at 1.2bar witch is pushing the stock ct20 turbo
Author:  dale [ Fri Mar 08, 2013 5:45 pm ]
Post subject:  Re: my st185 rebuld hoping for 400bhp maped at 1.6bar and 39
interesting as I wasnt arguing your power mixer, i was wondering why it was so low compared to last time as yours smoked that last time was all.

regarding what people "know" and dont know your engine or my engine may and will be totally different and the fuel maps as you should know too make a hell of a lot of difference.

Where in gods name you got 380bhp at the fly from 256bhp Treacle is an interesting one as i make it more like 325-340bhp at the fly... 380 would be a totally insane transmission loss mate. ;)

The dyno quoted me at 256 with 325.9 at the fly or there abouts, If i rework the transmission loss to the same loss as what my brothers was calculated at by Dave Rowe when he mapped the motec, I make 341bhp at the fly.

So if you know more about losses and mapping than that of a world renowned mapper then maybe you should take up a new job in mapping rally cars and drag cars fella. ;)

and to be fair mixer, i have seen many ct20's make 218bhp at the wheels, using dyno dynamic dynos
Author:  dale [ Fri Mar 08, 2013 5:55 pm ]
Post subject:  Re: my st185 rebuld hoping for 400bhp maped at 1.6bar and 39
this isnt about my car so i'm not going through pointless pub talk but specially for you treacle here are two previous runs about 4 months prior to my last run in which they quote 250 and 320 respectively which again questions your insane transmission loss theories.

Image
Image


just noticed its missed off the boost , i shall have to dig them back out and re scan them at some point.
Author:  jgtcracer [ Fri Mar 08, 2013 6:08 pm ]
Post subject:  Re: my st185 rebuld hoping for 400bhp maped at 1.6bar and 39
having read a few different articles regarding drivetrain losses with respect to 4wd cars, 17-25% seems the agreed value, of course this is completely dependent on modifications.

Even calculating a worst case scenario 25% loss at 256bhp whp that still works out at 320bhp @ fly

seems reasonable to me like :D
Author:  dale [ Fri Mar 08, 2013 6:17 pm ]
Post subject:  Re: my st185 rebuld hoping for 400bhp maped at 1.6bar and 39
cheers jgt, think to think of a loss of insane proportions you need to be smoking crack or something! haha

i just base my transmission calculations on the Dave Rowes from my brothers as to be fair... he is the god of motec and knows slightly more than most of us here like.

But this isnt about my car so thats all from me on that subject, i was just amazed that it went so low compared to the massive power prior
Author:  mixer72 [ Fri Mar 08, 2013 6:23 pm ]
Post subject:  Re: my st185 rebuld hoping for 400bhp maped at 1.6bar and 39
i not got a clue how its all worked out lol i just know the car is bloody quick :) think there is a lot that can come in to it, like wheels size drag in the gear box if you brakes a binding it all makes a diffence in wheel power calculation
Author:  mixer72 [ Fri Mar 08, 2013 6:28 pm ]
Post subject:  Re: my st185 rebuld hoping for 400bhp maped at 1.6bar and 39
just pulled up my old print out

Image

at the wheels
Image

its seem i dident lose as much power aon this dyno so may be its the roller calculation that is out at Interpro
Author:  mixer72 [ Fri Mar 08, 2013 6:30 pm ]
Post subject:  Re: my st185 rebuld hoping for 400bhp maped at 1.6bar and 39
here is an other of my print outs

bhp at the wheel and air/fuel
Image


bhp at fly and torque
Image

again not as much power lose
Author:  dale [ Fri Mar 08, 2013 6:32 pm ]
Post subject:  Re: my st185 rebuld hoping for 400bhp maped at 1.6bar and 39
dont worry, i wont take offence at being wrongly accused. ;)
Author:  mixer72 [ Fri Mar 08, 2013 6:33 pm ]
Post subject:  Re: my st185 rebuld hoping for 400bhp maped at 1.6bar and 39
lol at dale :)
Author:  dale [ Fri Mar 08, 2013 6:35 pm ]
Post subject:  Re: my st185 rebuld hoping for 400bhp maped at 1.6bar and 39
haha, im only playing mate, just made me laugh as id want to be high as a kite to think we would lose 120bhp from 256at the wheels, thats crack talk haha :D
Author:  Sirius [ Fri Mar 08, 2013 6:42 pm ]
Post subject:  Re: my st185 rebuld hoping for 400bhp maped at 1.6bar and 39
Remember that wheel horsepower is not calculated - its measured. Its the flywheel figure that is calculated.

The only way to truly measure the engine output is on an engine dyno.
Author:  mixer72 [ Fri Mar 08, 2013 6:44 pm ]
Post subject:  Re: my st185 rebuld hoping for 400bhp maped at 1.6bar and 39
this is what i made at the flywheel on a ct20b

Image

dident get a wheel print out :(
here is another print out with ct20b turbo

at 1.1bar
at the fly wheel

Image

at the wheels
Image


i see a trend the more power you make the more power you lose at the wheels :(
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