N/A Tests complete
 

Yesterday we conducted our series of N/A tests on the Renesis. This is a standard, unopened 6-port motor with std fuel injectors, intake runners and throttle body.

We did tests with the stock exhaust manifold and cat, and with a set of Phil Laird custom extractors, basically as per what is fitted to Wildcard's car.

Here are some various pics of the setup just before startup...

Overview showing inside dyno room:
https://www.rx8club.com/attachment.p...id=78088&stc=1

Other side, showing coupling to retarder etc.:
https://www.rx8club.com/attachment.p...id=78089&stc=1

Load cell:
https://www.rx8club.com/attachment.p...id=78090&stc=1

View from control room:
https://www.rx8club.com/attachment.p...id=78092&stc=1

Another view inside control room showing dyno control panel, and MoTeC ECU Manager running on the laptop:
https://www.rx8club.com/attachment.p...id=78091&stc=1

5MB Video here:
RX-8 Renesis engine running on Engine Dyno

The video is with the extractors on (obviously!). This is actually 3 clips, merged into one. The power pull (middle bit) was not really straight after it was started - i.e. it had a chance to get to operating temps first, and to cool down before it was shut off. I just clipped the boring bits out. Yes, there is a bit of a water leak at the front that doesn't affect things. I think that might be dripping down the hose from the water tank.

You can see the cable operating the throttle, under automatic control from the dyno software. At the start of the run, you can see it back off to idle, then open up to full throttle - the retarded then kicks in and holds the engine at 4000 RPM for about 3 seconds, then ramps up to 8500 RPM at a pre-determined rate, all the while measuring the load. Pretty trick. We could program in a automated drive cycle like on that F1 video I showed once before. Would LOVE to do that!

When the engine first starts, the noise is nice and crisp, but by the time the power pull is run, the exhaust fans in the cell have started up, so there is an annoying background noise. BTW - The camera is on a tripod inside the dyno room. You can here the exhaust fan noise after the engine is shut down.

Hope you enjoyed that, expecially the red-hot header pipe.

The results...

Hmm. This engine, after tuning for maximum power, puts out significantly less than the 238HP as published by the manufacturer. The results of the dyno are corrected for atmospheric conditions. Were not going to publish the actual figure - it will cause too many arguements.

The best bit - Phils Laird's "Hymee Enhanced" extractors are worth a genuine 14 HP and 7 ft-lbs. The gains were made right accross the board. The total HP gain was more than 6% over the baseline. (a hint for those numerically minded :) )

One other thing to note - this configuration suffers thought the mid-range a little bit, as we had all the ports "hard wired" in the open position. Since it will be eventually blown, then this is not of concern to us now, and doesn't affect the top end results anyway. The important bit is the power (hence torque) was up on standard all the way through the test.

Cheers,
Hymee.

Where is the MAF and what did you use as an intake?

extractors?

Mark

Is the Number with FIVE percent??

Thanks.

PM if you must - I promise I'd NOT make a stink. :)

What MAF? I'm not using one. God's intake - the atmosphere. We are finding out the capabilities of the engine. There is nothing to be gained for my testing to test the intake in front of the TB.

Cheers,
Hymee.

Check out the vid, man!

Cheers,
Hymee.

my bad--i just looked at the pics.

i may have to invest in a set :)

extractors= headers.

was the torque equal to or close to the published number?

Your extractors are getting a bit hot I see. As for the HP observed. Based on the clues it fits with the advertised amount. At least the amount advertised for the 06.

EDIT: Which is still makes it the most powerful 13B to date.

Is the 6% HP gain the area under the curve?? or its peak power
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0hAssSandwich

Yep - I use the terms interchangeably. Grandad calls them extractors, I call them headers.

The peak power was less than advertised, hence the torque at that point was less. I'd have to go get the print out again (not with me at the moment) to give a decisive answer comparing max torque with that advertised.

Cheers,
Hymee.

You can work it out from the hints I have given. ;)

Cheers,
Hymee.

Not the 238HP advertised amount. Or are my clues wrong...

Nope - they are correct.

Cheers,
Hymee.

wow, middle tube on the extractor (header for all us yanks) gets significantly hotter than the outside ones.

if i did my numbers correctly, it looks like the approximate drive train losses of 40 horsepower looks to be pretty accurate.

thanks for all the hard work hymee.

The area under the power curve is the integral of power isn't it? I guess that would be the work done, as power is the rate of doing work.

It is the peak power. However, those headers show a similar gain all the way through the dyno graph.

Cheers,
Hymee.

probably 220 hp. In the ballpark of what I have always felt like it was. That also would explain the low dyno results at the wheels.
olddraggerl

Thats because the middle tube is getting an exhaust pulse twice as often as then end one. The end ones do one rotor each, the middle exhaust port is siameesed between both rotors.

I'm not worring about drive train losses just yet. I'm looking at what she makes at the flywheel. When we finish our development on the engine dyno and install it in a car, we can go back on the rollers and make that comparison using like equipment (i.e. using DynoLog chassis dyno).

No one has shown me they worked out the maths properly, yet :aroused:

Cheers,
Hymee.

Go check Mazda the currently advertised HP for the 6 speed is 232 HP ... they changed it from last year (05). So with the clues it works for the current rating.

Click on the specs tab.

http://www.mazdausa.com/MusaWeb/disp...ehicleCode=RX8

You are the closest so far. Lets be more exact, and say the headers gave a 6.3% increase.

Cheers,
Hymee.

Thanks for that link, mate. But remember, the 6.3% gain of 14HP is over what we measured on the stock engine. Old draggers number is closer to what we measured.

Cheers,
Hymee.

No doubt, the OEM tuning is part of the equasion for the "advertised" peak power.
The "raw" potential of the motor is probably inline with the late N/A FCs (plus the compression ratio difference).

222 =d
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AlexisXBeauty cam

Who said 222? Not me :yelrotflm :naughty: :p:

Hmmmmm.

My calc must be broken 14 is not 6% of 222...

He said 6.3% to be exact, that 0.3 makes 10hp difference hahaha
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