Jump to content
SAU Community

Recommended Posts

Hey guys I was told when I purchased my car that it made 314kw however when it was recently dynod it only made 280kw at all 4. I'd like to think it did intact make 314 kW but in rwd.

My question is how much of a power difference can you expect between an awd dyno run and a rwd dyno run? I've heard numbers like 12-15% thrown around but I'm wondering if anyone has actual figures from their own experience.

Thanks in advance

Link to comment
https://www.sau.com.au/forums/topic/451423-r32-gtr-drivetrain-losses-awd-v-rwd/
Share on other sites

This has been discussed numerous times on sau man.

The rb26 gtr is a majority rear wheel drive car. It's Not like a evo or wrx where the car has a exact percentage split front to back.

I have seen people dyno their car in awd and then rwd in a gtr and the reading was marginally different.

That being said, different dynos tell different stories. And how the tuner sets it all up.

Plus, the majority of the losses are not in the drivetrain - they occur at the tyre/roller interface. As mentioned above, the GTR's AWD characteristics make it very difficult to work out whether the effect of having 4 places to lose power (through roller slip) is more significant than spreading the power delivery around to 4 places so you actually get less slip.

Yeah fair enough. My car was dynod on a hub dyno when it made 280kw, so you'd think with tyre slip out of the equation it would actually make more power.

Was hoping to see some dyno graphs of someone doing a rwd run then awd run back to back. But I understand what you're saying about it being different to a evo style awd

Edited by redot

Why would anyone bother doing back to back comparisons?

A dyno is a tuning tool. Make as much power as possible on the dyno it's on when being tuned. Comparing dyno readings will end in tears.

You mod a car to make power so it goes faster, not for a line on a page.

  • Like 2

Yeah fair enough. My car was dynod on a hub dyno when it made 280kw, so you'd think with tyre slip out of the equation it would actually make more power.

A hub dyno doesn't require any downforce on the rear axle. If you strap a car down hard to get grip on rollers you lose many powerz. More power the more it needs to be strapped down.

You can see why hub dyno's are prefered...

Yeah I was just curious to see if there was a difference on paper between awd/rwd irrespective of tuning...

Rb26 forged, gt3582r, 850cc injectors, power fc dejetro, pulp, 14psi

Car made 354kw on 20psi at all 4 after the tune

Actually in the interests of science Shred Industries Performance did this test on an R32 GTR in 2011 and got 200.6KW and 189.7KW.

Don't know what kind of dyno - was a Dynapack but don't know if rollers or hub.

I have the chart if anyone is really keen to see it.

post-49463-0-55700700-1417823425_thumb.jpg

Actually in the interests of science Shred Industries Performance did this test on an R32 GTR in 2011 and got 200.6KW and 189.7KW.

Don't know what kind of dyno - was a Dynapack but don't know if rollers or hub.

I have the chart if anyone is really keen to see it.

Awesome mate, thanks for that! Yeah I would love a look

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • Good luck on the weekend mate
    • Must have been an absolute nightmare to drive when the power steer was out, the rack ratio/wheel size/caster is all set up for power assistance
    • Welcome to SAU, what are you looking at buying?
    • I checked the injectors again (1 and 2, since they’re easiest to access) to make sure they weren’t clogged. Even though the entire fuel system had been cleaned, I wanted to be certain. Everything looked clean, so I reinstalled and connected everything. When I started the car to confirm everything was okay, it immediately revved up high, so I shut it off straight away. I checked to see if I’d missed a vacuum hose or something, but everything was connected. On the second attempt, the car ran without the high idle, but I noticed a distinct “compressed air” sound coming from the engine bay. Tracing the sound, I pushed injector #6 forward slightly and the noise stopped — it turned out it wasn’t seated properly, despite the fuel rail being bolted down. While holding it in place, the car idled steadily without stalling and ran for over 5 minutes. At this point, I pulled all six injectors out just in case I hadn’t seated them correctly or dirt had gotten onto the O-rings. Unfortunately, I discovered that I had damaged 3 out of 6 injectors (the OEM 270cc ones) during installation. So yes, this was my fault. Since only the pintle caps were damaged, I’ve ordered a Fuel Injector Service Kit from NZEFI to refurbish them. In the meantime, I reinstalled my new injectors – the car now idles fine for over 15 minutes without stalling. I have not attempted to drive it so far. It’s not perfect yet, as it hesitates when the throttle is pressed, but it’s a big improvement. Unplugging the IACV with the new injectors idles at around 800rpm, even with the IACV screw tightened fully. But this is probably due to tune.
    • I wanted to try and preserve the front bumper as long as possible, they're not cheap and are made to order in Japan. Taking inspiration from my previous K11 Micra build where I made an undertray for the Impul bumper, I did the same for this BN Sports bumper but a little slimmed down.  This time round I only made a 'skid plate' (if that's the correct wording/term) for just the bumper surface area, the Micra version covered the gap like an undertray. Starting off with a sheet of mild steel approx. 0.9mm thick 4ft x 2ft in size. I traced around the bumper, cut it out and cleaned the edges. Luckily I was able to get two halves from one piece of metal In the video I installed it as is, but I've since then I've removed it to spray and add a rubber edging trim. The rubber trim is suitable for 1-2mm and it's a really nice tight fit. The bolts had to be loosened due to the plates being too tight against the bumper, the trim wouldn't push on I used some stainless M6 flat headed bolts for a flusher finish (rather than hex heads poking down), I believe this style fastener is used for furniture too incase you struggle to source some. The corner's are a little wider, but this may be an advantage incase I get close to bumping it  The front grill got some attention, finally getting round to repairing it. Upon removal one fixing pulled itself out of the plastic frame, one side is M8 that fixes inside of the frame, where as the other side is M5. Not knowing I could get replacements, I cut down an M8 bolt, threaded it inside the frame along with a decent amount of JB Weld.  The mesh was replaced to match the bumper. One hole on the bonnet/hood had to be drilled out to 8mm to accommodate the new stud, once the glue had set it could be refitted. I think the reason the grill was double meshed was to hide the horn/bonnet latch (which makes sense) but I much prefer it matching the bumper Bumper refitted and it's looking much better IMO The Youtube video can be seen here: https://www.youtube.com/watch?v=bVZP35io9MA
×
×
  • Create New...