how can you tell if its ported?

[rx-paul]

hi had this dyno done saturday at powerstation can you tell if your engine has been ported fron a dyno?
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mod are
knightsport ecu
knightsport boost controller
hks downpipe
de-cat
titanium cat back
air pump removed
lightened pullies
waldbro fuel pump
ran at 0.9bar on v-power

[dandan]

I dont know but thats pretty good power!

[nikp]

Wheel power 253bhp, and engine power 347!? Who are they trying to kid!!!?

they reckon there\'s 94bhp lost through transmission - Or, put another way, 27% losses!


On a 250~bhp wheel figure, it would be more like 300~bhp power at the fly. (Impossible to tell if it\'s been ported, but with those wheel figures it\'s unlikely to have been.

[andysmee]

nikp, Powerstation are OK IMHO. Those figures are based on a run down test for drag and 27% sounds OK. What makes you think they are so off?
 
I used to take my Coupe to Powerstation and it ran 150rwhp which was about 200fwhp on the run down test. This was perfect and matched the book value for the car - FWD ~25%
 
I assume you have a lot of experience but I also know that they use a tried and tested method for their power dyno tests so why are they likely to be so far off IYHO?
 
P.S. Not trying to be a PITA, but I don\'t understand why you are so surprised when ~30% losses is not an unheard of figure?

[nikp]

Here, this may make interesting reading for you, concerning rolling road and their \'accurate\' flywheel figures:

http://www.pumaracing.co.uk/power3.htm

It\'s more reliable to go by the wheel figure. It\'s all pub talk at the end of the day though. It\'s how it performs in the real world is the key!

[rx-paul]

this is the first time i have run the car on the dyno. the lads at powerstation said not to take much notice of the wheel bhp for some reason and juct to look at the corrected power (361.6) because of the way there dyno is set. this was part of a rolling road day and there were a couple of standard scoobies that run which made the book bhp so it couldent be that far out i hope anyway.
all i wanted to find out was if the engine was ported concidering the mods on and the bhp?

[Ada7]

i got told that you lose about 18% of the power though the transmission.
My old car (Andy\'s Smee\'s) was showing 280bhp at the rear wheels, which works out to be 341ish at the fly. Might be slightly more than that now btw Andy as i changed the indution pipes afterwards as they were the standard rubber ones and had loads of holes in them.

As has been said, this is all pub talk anyway

Adam

[nikp]

The higher the power you go, the smaller the percentage the lossed will be. According to Puma racing given in that link, and the figures are reasonable, you lose about 17-18% (roughly speaking) up to about 300bhp. Above that, the losses drop to around 11-12%. So, on an output wheel figure of 250bhp, you\'re looking at a rough flywheel output of 305bhp. That\'s taking into account 18% transmission losses.

Transmission losses will never be as high as 27-30%. Even 4wd vehicles are liekly to lose in the region of only 22%.

[trevtubby]

at WGT on their dyno I got 240ishWHP, which equated to 281.5bhp at the flywheel.

I`m not sure how they got 360bhp at the fly with 253bhp at the wheels..surely the at the wheels figure is the only accurate reading, as the flywheel figure is basically an educated guesstimate?

[nikp]

I`m not sure how they got 360bhp at the fly with 253bhp at the wheels..surely the at the wheels figure is the only accurate reading, as the flywheel figure is basically an educated guesstimate?

Unless tested on an engine dyno, the flywheel figure is always a guess/estimation. You know roughly what the transmission losses will be, so can estimate the figure using that.

[trevtubby]

Unless tested on an engine dyno, the flywheel figure is always a guess/estimation. You know roughly what the transmission losses will be, so can estimate the figure using that.

Yeah thats what I thought , how do they figure out the losses though? is it something to do with them putting the clutch in after the run and letting the wheels come to a stop by themself...then the dyno figures out the transmission losses by how long it takes the wheels to stop spinning?

or is that complete bollox, maybe someone told me that one night whilst drunk in the local haha.

[nikp]

Basically, the use a rough figure. Read the article in the link i posted above. But, to cut it short, they use roughly 17-18% for rear wheel drive cars, 22% for 4wd cars, and about 15% for FWD cars.

In other words, take your RWD BHP figure, and divide by 0.82 (18% losses)to get a rough indication of what your flywheel power could be.

[trevtubby]

oh right ok, I thought every car would be different though, didnt think they would just use the same % for any car with the same type of drive.

ah well nevermind lol.

[sadgoth]

using the calc in that link i.e. (253.3rwhp + 10bhp) / 0.88 would mean that in this case the FWHP should be: 290.2fwhp

this sounds far mre realistic (some may say low - but a least it is better that than huge pub talk figures that mean NOTHING)

[nikp]

oh right ok, I thought every car would be different though, didnt think they would just use the same % for any car with the same type of drive.

ah well nevermind lol.

It\'s the only way you can do it! As i said, read the link. It\'s very interesting stuff.