NB8A Kw at rear wheels

DarrylA · Postby **DarrylA** » Thu Mar 26, 2015 2:39 pm

Hi guys
Just out of curosity I was wondering what the standard rated kW at the rear wheels was for a 1.8 NB8A.
Like to compare what I've picked up.
Thanks
:NB8A:

hks_kansei · Postby **hks_kansei** » Thu Mar 26, 2015 3:07 pm

Depends on the dyno, the settings, and all the other stuff.

Mine has Dyno'd 79kw on a Dyno Dynamics Dyno (aftermarket muffler)
and 76kw on a Mainline Dynolog Dyno (DIY mania intake, aftermarket muffler)

The Mainline is known to be pretty pessimistic, but also pretty consistent. So I would personally say that one would be closer to the truth.

As for the mods on my car, the muffler would have been lucky to add anything, since the midpipe etc is still stock, and the intake would have been only minimal too.
Any gains/losses on those mods I would expect to be well within the margin of error of any dyno.

rascal · Postby **rascal** » Thu Mar 26, 2015 6:41 pm

From the Dyno days that the Vic club has run, the average for a stock standard NB8A is around 72rwkw.

Trackphotos · Postby **Trackphotos** » Thu Mar 26, 2015 8:26 pm

rascal wrote:From the Dyno days that the Vic club has run, the average for a stock standard NB8A is around 72rwkw.

That's quite a loss from the claimed power. Stated 106fwkw, or 145bhp. 72rwkw is only 95rwhp, so a full 50hp loss through transmission, over 33%. I suppose 15+ years of wear and tear will do that, but it makes me even happier to know that I can keep up with r33s and xr6 turbos at Lakeside with 1/3 the power and 2/3 the weight.

Vat · Postby **Vat** » Thu Mar 26, 2015 8:36 pm

30% is pretty normal for rear drive - gearbox and a diff which includes a 90% change in direction. That's before allowing for engine and drive line aging, plus dyno differences...

Trackphotos · Postby **Trackphotos** » Thu Mar 26, 2015 8:42 pm

Vat wrote:30% is pretty normal for rear drive - gearbox and a diff which includes a 90% change in direction. That's before allowing for engine and drive line aging, plus dyno differences...

I thought as a general rule it was closer to 25% manual, 30% auto.

Magpie · Postby **Magpie** » Thu Mar 26, 2015 9:17 pm

There is no general rule because of so many different factors, FWD, RWD, AWD, diff, weight etc. In addition the numbers can be different on a hub or chassis dyno. Rather than attempting to convert between stated OEM values and RWHP using a percentage or a fixed horsepower value, just accept the fact that these two types of HP measurements aren't easily correlated and forego any attempt at doing so.

david_syd_au · Postby **david_syd_au** » Thu Mar 26, 2015 9:36 pm

My NB8A race car with
- stock internals, 100k km engine
- race exhaust, loud and no cat
- pod air intake with no MAF, stock throttle body and manifold
- Megasquirt ECU
produced 84.4 rwkw on the Deckspeed dyno (fwiw on a hot day in the high 30s)
I suggest that would be approaching the upper limit of what could be achieved with stock internals, and simple external mods (eg no ITBs)

rascal · Postby **rascal** » Thu Mar 26, 2015 10:02 pm

David,

I concur.
My NB8A, also with ~100K with essentially the same mods, (custom CAI, catless exhaust, ECU otherwise bone stock) did almost exactly the same output at 84.6rwkw.

pcmx5 · Postby **pcmx5** » Thu Mar 26, 2015 10:09 pm

3 years of dyno results on the same Dyno Dynamics set up for the Vic MX5 club showed an average 30-33% drive train loss.It also showed that NA6A's had a better ratio of loss than than NA8A's or NA8B's so Mazda may have had a bit of a "fiddle factor" in their measurements as evidenced by their need to replace cars/compensate owners under US consumer law when their claim of 113KW for NA8B.s was found to be false.

Peter.

hks_kansei · Postby **hks_kansei** » Thu Mar 26, 2015 10:31 pm

pcmx5 wrote:3 years of dyno results on the same Dyno Dynamics set up for the Vic MX5 club showed an average 30-33% drive train loss.It also showed that NA6A's had a better ratio of loss than than NA8A's or NA8B's so Mazda may have had a bit of a "fiddle factor" in their measurements as evidenced by their need to replace cars/compensate owners under US consumer law when their claim of 113KW for NA8B.s was found to be false.

Peter.

I'd suggest the NA6 having less drivetrain loss would be to do with then having a shorter diff than the NA8 and NB8A.

ie: 4.3 vs 4.1

pcmx5 · Postby **pcmx5** » Thu Mar 26, 2015 10:38 pm

DarrylA wrote:Hi guys
Just out of curosity I was wondering what the standard rated kW at the rear wheels was for a 1.8 NB8A.
Like to compare what I've picked up.
Thanks

Well come on tells us what you picked up with your new head, before and after on the same dyno,hope it was all good!!!

cheers,

Peter.

DarrylA · Postby **DarrylA** » Mon Mar 30, 2015 4:54 pm

Thanks so much for your import guys.
Happy with my decent gain, so now ready for more fun than before.

DarrylA · Postby **DarrylA** » Thu Apr 02, 2015 10:06 am

Ok for those who would like to know, I picked up 30kw with a mildly worked head with cams and a light hair cut.
It now appears to have bags of torque.