Flywheel /rear wheel hp

[aussier33]

How much really is lost as a percentage from flywheel to rear wheels on say r33

I have heard 20 % to 35 % this is a big range anybody have a better idea I am talking manual trans.THX

[2rismo]

I reckon on a good, tight 5 speed man tranny, your dreaming to expect to lose anything LIKE 30%...

i'm saying 15-20%

Adrian

[EnricoPalazzo]

Me thinks between 20-30%

[b2barker]

Me thinks it is closer to being a fixed loss (xkW) than a percentage.

[Steve]

Originally posted by b2barker

Me thinks it is closer to being a fixed loss (xkW) than a percentage.

Agree completely.

Loss may increase slightly with increased BHP, but I can't see how it would be linear, only marginal.

[rev210]

the loss isn't linear as the frictional forces are not able to be calculated in a linear fashion.

[Sydneykid]

Hi guys, from our experience using both engine and chassis dynos (roller) on over 20 Skylines..

Standard R32 GTST

162 kw

220 bhp

110 rwkw

145 rwhp

Standard R33 GTST

185 kw

250 bhp

125 rwkw

170 rwhp

Standard R34 GTT

206 kw

275 bhp

145 rwkw

195 rwhp

Modified R32 GTST

265 kw

355 bhp

210 rwkw

280 rwhp

Modified R33 GTST

285 kw

380 bhp

220 rwkw

295 rwhp

Modified R34 GTT

305 kw

410 bhp

240 rwkw

320 rwhp

Our old RB30DET (with a GTR box in 2wd)

345 kw

465 bhp

280 rwkw

375 rwhp

Whilst the losses aren't perfectly linear they are pretty close, a R32 GTST with manual transmission looses about 52 kw through the drive train, an R33 GTST also with manual transmission losses about 60 kw through the drive train and an R34 GTT looses about 62 kw through the drive train.

It does not seem to matter what the rear wheel power is the losses are fairly constant ie; if you double the power output at the wheels the losses don't double. They go up a little bit, but not even remotely close to linear.

This is a bit of a political subject because it is always preferable to tell people the highest power number possible. So I often here stuff like.........

"My car when standard had 185 kw at the engine and 125 rwkw, now it has 250 rwkw, so it must have 370 kw at the engine. That's 500 bhp". Well, sorry if it deflates some people, but I believe it would really be 250 + 60 = 310 kw (415 bhp).

For the clutchless people, the losses seem to be about 20 rwkw more than for manuals.

Hope that adds to the discussion

[Sydneykid]

Hi guys, let me throw this one in for further thought....

It is accepted that energy can neither be gained nor lost, however it can be converted into other types of energy (that's how brakes work, turning kinetic energy into heat). Of course the Einstein E=MC2 disproves this, but I don't think there is any atomic reactions going on in my Skyline.

So if the losses are linear, where is the extra energy going? It's not "LOST", it can realisically only be converted into heat. If my gearbox and diff heated up at that sort of rate, there would be big lumps of molten aluminium all over the dyno room floor.

Ponder on that for a while

[EnricoPalazzo]

Hmmm sounds good SydneyKid, that is definately the best answer i have read when it comes to this matter.

[rev210]

Originally posted by Sydneykid

Of course the Einstein E=MC2 disproves this, but I don't think there is any atomic reactions going on in my Skyline.

E = energy (we all know that one)

C = the speed of light (assumed to be a constant once but isn't)

M = the Mass defect (subtract the 'lost' positron/electron mass from the specific nuclear reaction from memory).

Conservation of energy applies to this equation still.

[N/A®]

Sydneykid,

So if a GTST loses 60kw thru the drivetrain, how much more loss does a GTR have over a GTST since its 4wd? say 300kw at all four wheels =???

[aussier33]

Thanks Guys it seems to be about 30% or there abouts if you are going to put a number to it . I wanted to know because after putting hks intake pod 3 inch mandrel bent exhaust hks ssbov and 11 psi boost rwkw only showed 165kw and i thought great thats only 10 % more than stock but its more like 20% more