BHP @ Flywheel vs BHP @ RW
Discussion
well I've been quoted transmission losses as being anything from 40-100hp. Only way you'll ever find out is to rip the engine out the car and mount it to an engine dyno to get an accurate flywheel figure. Oh and don't believe Vauxhall's figures for standard cars - they're based on a couple of test cars/engines and with the LS series it appears that there can be substantial differences in the figures they'll put out for the same tune.
Most on here are agreed that if you want to talk numbers then you should only really concentrate on the rwhp as measured on a rolling road before and then after fitting mods. Anything else is pure speculation!!
Oh and if you're on a rolling road - open the bonnet
Most on here are agreed that if you want to talk numbers then you should only really concentrate on the rwhp as measured on a rolling road before and then after fitting mods. Anything else is pure speculation!!
Oh and if you're on a rolling road - open the bonnet
greens vauxhall said:
stevieturbo said:
Gelf VXR said:
greens vauxhall said:
Correct!
What are the transmission losses?
They are the losses through the transmission.
They can be greatly reduced, by removing your transmission
Please mod shut the thread quick!!!!!!
But it's ok for you to start another dyno thread??? been said on here by others often enough. Couple of tuners have also mentioned that base cars they've seen (04 cv8s) have been putting out what they reckon to be <<<300 before tunes and mods, well down on the quoted 329. As for VXRs again I've heard quotes of figures in the 375-385 though thats a much rarer occurence than for the cv8s. Generally the VXR's are reckoned to be much closer to spec but the odd one still slips through.
Rob K said:
greens vauxhall said:
stevieturbo said:
Gelf VXR said:
greens vauxhall said:
Correct!
What are the transmission losses?
They are the losses through the transmission.
They can be greatly reduced, by removing your transmission
Please mod shut the thread quick!!!!!!
But it's ok for you to start another dyno thread?????
well_fans said:
been said on here by others often enough. Couple of tuners have also mentioned that base cars they've seen (04 cv8s) have been putting out what they reckon to be <<<300 before tunes and mods, well down on the quoted 329. As for VXRs again I've heard quotes of figures in the 375-385 though thats a much rarer occurence than for the cv8s. Generally the VXR's are reckoned to be much closer to spec but the odd one still slips through.
Nobody will ever know until they remove an engine and run it in the way the manufacturers do.
Here are a couple of extracts from the GM web site.
2004 GM engine performance data
2005 GM engine performance data
I think there are some people who still believe that engine production is a tin pot business that is poorly controlled. Things have moved on since the iron block engines of the 1960's! Production tolerances are much tighter!
Here is a link to the Sema site that talks about dyno and engine testing from an independent view an interesting read!
Sema dyno discussion
2004 GM engine performance data
2005 GM engine performance data
I think there are some people who still believe that engine production is a tin pot business that is poorly controlled. Things have moved on since the iron block engines of the 1960's! Production tolerances are much tighter!
Here is a link to the Sema site that talks about dyno and engine testing from an independent view an interesting read!
Sema dyno discussion
grizz said:
that's 398 @ the flywheel .
How do you know its 398 at the flywheel ?
The reason so many jibes in this thread, is the fact that virtually ALL rolling roads, use an element of guesstimation when it comes to quoting flywheel figures.
Some do try and make measurements, others really do just pluck a random figure from thin air, and apply it.
So really, flywheel figures as quoted by rolling roads, are meaningless.
Its also been said dozens of times. The UK is pretty much teh only place in the tuning world, that is daft enough to still quote flywheel figures. All the other big players rightly use wheel figures.
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