RWKW to BHP and Back

[IanH]

Hiya all, after reading the wastegate size thread I noticed that some of the rwkw figures seemed very high when compared to mine (we use bhp in the UK so I'm not too sure of the conversion). This is how I think my conversion works

I have 400bhp at the flywheel, which is 300kw at the fly, which is 200rwkw

Does that rwkw figure seem low?

Here's my maths, 400bhp/1.33=300kw and rwkw is 2/3 of fly kw so =200kw

Anyone got any idea? Going from the numbers SydneyKid used in the wastegate thread I should have around 250rwkw?

Cheers for your help......................................................IanH

[sewid]

Guessing drivetrain losses is a waste of time. Just go down to the nearest workshop with a dyno and at least get a good idea at the approximate rwkw/rwhp figure. The cost is really insignificant for a quick power run.

[GTRman1992]

Rule of Thumb Kw = 0.75Hp. (e.g. 400Hp = 300Kw)

Drive Train Losses 30%.

But as sewid said, nothing beats a dyno run for the truth.

[nicknick]

if you had 330 rwkw what would you have at the motor in HP

[Elithrar]

It would depend on your drivetrain (AWD drivetrains lose more power than that of a RWD or FWD 'train).

I'd estimate about 500hp (330kW x 1.35 + 55) on a RWD setup, or about 530hp on an AWD setup. And remembe, these figures are just estimates.

[IanH]

Well, I've had her dyno'd in her current state and got 253rwhp, which works out to 190rwkw (not far off the 200 I'd guessed) but again this seems low when other people mention their 230-250rwkw figures for GTS-t's in the wastegate thread. I've had a lot of work done on the engine (new turbo, FMIC, bigger injectors pumps, Boost to 17.5psi, clutch etc) and wonder what other GTT owners are getting for theirs?

Cheers..........................................................................

.....IanH

[3R1K]

Hi there, you got 190 rwhp for what kind of modification?

on 4th gear, I got 217.7 hp, with full turbo back, and air filter, running 8 or 9 psi

[IanH]

Hi there, you got 190 rwhp for what kind of modification?

on 4th gear, I got 217.7 hp, with full turbo back, and air filter, running 8 or 9 psi

Opps, I meant 190rwkw not hp anyway, Heres the list -

Engine

Trust TD05-18g Turbo

HKS S-Type FMIC

Blitz SBC-iD @ 1.2bar (17.5psi)

Nismo 480cc injectors

Nismo Fuel pump

Tomei 1.4mm Headgasket

NGK Iridium Plugs

Apexi PowerFC & H/C

HKS Downpipe

HKS De-cat

Blitz Nur spec Exhaust

z32 AFM

Trust 13 Row Oil Cooler

Stock Air Box but with a Nismo S-Tune filter in (Ive bought an Apexi PowerIntake filter which arrive next week)

Other

R33GTR Brembo Front Calipers and discs with Ferrodo DS2500 pads

R34GTR Clutch

Lots of carbon fibre bits

HKS SSQV BOV

Cusco Catch Tank

R34GTR Rims

Top Secret copy Front bar & Bonnet

Tomei Kevlar Timing belt

With all that I'm making a little short of what I expected (which was 200rwkw) but the induction kit should help that out.

It just seems odd that people are making a lot higher rwkw figures but with less engine work being done, which was why I wanted my maths checking!

[MattyB]

i have a tad more power out of my r33 gts-t. only engine mods being fmic high flowed turbo an bigger fuel pump. everything else standard. i would say maybe you need someone to really tune your car to get the best out of what you have.

[IanH]

i have a tad more power out of my r33 gts-t. only engine mods being fmic high flowed turbo an bigger fuel pump. everything else standard.

This is the sort of thing I'm on about. My car is producing over 100bhp more than standard (276 Vs 385) but a GTS-t has the same amount from only minor mods. There has GOT to be something going wrong in the way I'm doing the conversion. There is NO WAY a a GTS-t can produce over 100bhp extra with those mods so that means my rwkw figure MUST be too low!

Can anyone make any sense of this as it's doin my head in!

[GTRman1992]

Don't get too fussed over it. How it goes on the street is all that really matters.

[JimX]

i have a tad more power out of my r33 gts-t.

What, you took your car to England to dyno it on the exact same dyno that IanH did? That shows real dedication!

[benm]

IanH if your car was here in Sydney and run on a Dyno Dynamics Dyno and you got 190rwkw with alllll those mods i'd be taking it all back and getting a refund

Either your tuner doesn't know what he's doing or your different climate and dyno conditions are putting your power figures out compared to here.

[whatsisname]

Ian,

To 2 decimal places the conversions are as follows:

1hp - 0.75kw

1kw - 1.34hp

My suggestion would be for you to go to your closest proper drag strip (0-400m) & tell us what 60ft, ET & most importantly MPH you get. These figures will go a fair way to telling you how much power you're making (when compared to the cars weight). Even a poor effort on the drag strip will give a good indiction when the full 60ft, ET & MPH is used.

Trying to compare YOUR dyno number with our Aussie dyno numbers isn't much good. For starters what type of dyno does your tuner use? How is the dyno configured, i.e what sort of drivetrain to fly difference does it show? For example, the US Dynojet dyno shows a much smaller drop btw flywheel to rw than Aussie dyno's USA 250hp ='s 210rwhp Aussie 250hp ='s 170rwhp

As a side issue, what is the Trust TD05-18G rated at?

EDIT: - One other small thing Ian, how did you figure your engine to be making 385bhp? I take it the UK dyno's have some form of rw to flywheel conversion, yes? Unless you've had your engine removed & run on a engine dyno even the 385hp figure is a bit of a rough estimate.

Cheers,

Matt

[3R1K]

I agree with benm, You can get way more KW with those mods, franks from sydney get 200 kw with one bar boost, with only full turbo bac, filter, HKS type S cooler, FMIC, tuned Power fc, oil cooler, replace head gasket.

I think you should tune your car elsewhere to produce better output

Can you send me picture of your car to [email protected] It looks awesome I guess. BTW r33 brembo brakes can be fit into r34 ?

[NXTIME]

Why did you choose to use the TD05-18G? That would be your power limiter in this case as I think the turbo is not able to flow more than 360-380HP @ 17-20psi.

How much power do you wish to make?

[EnricoPalazzo]

If u search the forums, sydneykid wrote an interesting post on flywheel to rear wheel losses. He believes the loss is a set figure rather then a percentage. Im not gettin into that debarcle but he says most 33's have a loss of 62kws from fly to wheels. Ie standard 33 Gtst with 187kws at motor will have 125rwkws. Sounds rite to me.

[IanH]

He believes the loss is a set figure rather then a percentage. Im not gettin into that debarcle but he says most 33's have a loss of 62kws from fly to wheels.

That sounds good to me as well! If I had 230rwkw + 62= 292rwkw*1.34 = 390bhp which is almost what I'm running (according to a Rollin Road dyno (385bhp)

now 230rwkw is more like the figure I was hoping for :headbang:

eriktufa - YHM