Hymee

iTrader: (1)

Hiya,

I did some work yesterday with a mutual friend regarding dynoing my RX-8 as a baseline for testing mods etc. (see https://www.rx8club.com/showthread.p...threadid=20001)

Here is my dyno plot:



Now if I supplied you with a graph with HP instead of kW, you would see it pulled almost 180 HP at the wheels. There is an old rule of thumb that says the HP at the wheels is about the same as the kW at the flywheel.

So I am now happy that my cars makes the power that Mazda claim it does. I hope Mazda are reading this and smile upon what I have disclosed

Cheers,
Hymee.

rpm_pwr

Congratulations on finding another 12kW!

-pete

Hymee

iTrader: (1)

Hehehe. That is easy. Just go to a different dyno

rpm_pwr

aahh so you chopped off "results plotted using shootout mode (refer manual for full details)...."

-pete

Hymee

iTrader: (1)

No, I didn't chop that off.

pricer01

Another good bit of info from the Professor of RX8s - wel done Hymee!!

I hope this isnt sacreligious and potentially I'm easy to please, but even if it was only 150kw, its a great car to drive.

Whilst I'm sure I'd enjoy 220KW, I'm not sure I'd want it 99% of the time.

Rob

richwu

I'm sorry, I might not read the graph properly, but we on the graph said there is a max of 177kw?? I'm puzzled.

AMG

Flywheel extrapolation

Hymee

iTrader: (1)

OK - I never said the graph shows 177kW. What I said was the graph, if converted to HP would be pretty close to 180 HP.

1 HP = 0.745701 kW
132kW = 177.0146 HP

Now, we have measured 177HP at the rear wheels. There are drivetrain frictional losses to take into account. A general guide ("rule of thumb") is that what you are making at the wheels in HP, is pretty close to what you are making at the flywheel (engine) in kW.

Using that rule of thumb, my car looks like it makes 177kW at the flywheel. If that was the case, we are seeing 45kW being soaked up by the transmission, just to turn the wheels.

Here is a real world comparison. I have witnessed a dead stock "300kW" HSV GTS Coupe on a chassis dyno pull 220kW at the tyres. This is a repeatbale situation on that dyno that has happened many times. If they lose 80kW at the tires, that is nearly double the losses than the RX-8. (BTW - My SS Commodore [i.e. non-HSV] made 235kW at the wheels on that dyno , so it had more power than a $100,000 car for about $2,500 in mods. Don't expect those same easy gains from your RX-8, boys and girls )

Cheers,
Hymee.

thklam

thanks.. now I know what is going on.

RIC SHAW

hi Hymee,
so when you did this with Phil Lard on the chassis dyno, what was the inertia and corection values in the dyno computer set to ???????
how is the work on fixing Canzoomers ecu going? have you guys got it working yet ?

RIC SHAW

Hymee,
i forgot to ask.
what did you do on the dyno with the wheel sensors ?????????????

RIC SHAW

hi Hymee,
so when you did this with Phil Lard on the chassis dyno, what was the inertia and corection values in the dyno computer set to ???????
how is the work on fixing Canzoomers ecu going? have you guys got it working yet ?

Hymee

iTrader: (1)

Ric,

I can't remember the actual correction factor, but the chassis dyno is in a room with a weather station, and we entered the temp, baro, humidity at the time. I'll have to ask about inertia, although it is a computer controlled electo/magnetic dyno, not an inertial one. Like you said, it is hard to compare dyno's in different shops, but for some reason mine made more power than what you are used to seeing.

What we found was my RX-8 runs on the dyno without throwing the ABS/TC light! So we didn't need to do anything special...

I started a thread in the Tech Garage about that, since I have only seen 1 "leather pack" (Wildcard) and 1 "Cloth Pack" (me) on the dyno. When I think back, and I also spoke to Mark M, it was only Wildcards car that exhibited the safe mode issue.

https://www.rx8club.com/showthread.p...threadid=20001

Has anyone looked at the number of teeth on the front wheel speed sensor (rotor), and compared it to the rear? The rears are easy to see, and is about 100mm diameter, right on the end of the half shafts. The front ones look like they are a different arrangement. The sensor is very close to the center of the hub, and the toothed wheel is hidden. Perhaps the teeth are inscribed in the hub (internal teeth). If the number of teeth are not the same, it might not be 100% useful to replicate the rear signal to the fronts.

Cheers,
Hymee.

Lock & Load

So from reading Hymees threads in the teck forum we still dont know what the drivetrain loss should be on an rx8 .

Figures of 17% ___35 % +++ or anything in between is not exactly accurate calculations .

Mazda head office has still not responded to my letter re :The actual power output figures on the Australian RX8 .

I know that some forum members feel strongly about pursuing this issue with Mazda , but i like to get what i pay for nothing more and nothing less .

The silence on this matter by mazda clearly indicates to me that something is not quite right .

The real power output issue continues in my mind to be a mystery until its proven otherwise .

My leather pack car will be dynod on the same dyno as hymees in the not to distant feature it should be interesting to say the least to see the differences in dyno results.

michael

pricer01

Michael

Like you, I'd like to think I get what I pay for. When I was buying my car the US debate about 184 was raging so I was quite direct with the dealer about the power output etc. Initially the dealer gave me the brochure but the back has the triple des secure disclaimer including a suggestion that specs change with no notice so check with the dealer. I pursued the dealer for a specific statement but the dealers hid behind the Mazda HO saying that Mazda do not provide these details.
Regardless, I do wonder if a claim of 'obtaining benefit by deception' or 'Misleading marketing' could be sustainable if their is proof of a material variation from the claimed specs ....

Lock & Load

Pricer01

Good to see that not all forum members are prepared to accept MAZDA HEAD OFFICE version of what the power output is on the RX8 .

I for one believe that mazda has pulled a shifty , and am working towards proving or dissproving the output theory on the RX8
.
I have written to a very prominent Law firm in Victoria who are awaiting my results and further testing before we decide the correct action to take regarding this matter .

As i stated earlier some forum members dont feel comfortable with anything other than positive praises being said about their RX8 , i love my car as much as the next RX8 owner but i refuse to bury my head in the sand and stay in the dark like a mush room , and be feed a whole lot of bullshit.

The issues as i see them are :

Correct power 177kw???(Mazda so far has refused to probe this figure)

correct fuel consumption figures .???? (not many people get anywhere near 12.6 ltr per 100km )



Why only 1 oil cooler ????? Mazda has not given a paussable reply .

It seems everyone is scared to asks the hard questions of mazda , maybe when the ACCC / or solicitors get involded mazda will reply to my questions .

Its a David versus GOLIATH type situation , but we all know the outcome of that battle .

cheers
michael

Hymee

iTrader: (1)

I thought someone posted an "offical" email reply from Mazda Australia standing by the claims that the engines make 177kw?

My car consistently gets 400 - 500 km out of 60L of fuel. 400km would be 15L/100km, and 500km would be 12L/100km. I normally get about 480+, so I stick with my 12.5 figure.

timbo

I think waiting for an "official" Kw figure is going to be a very futile activity. As we have seen here with dyno tests, there are many variables affecting readings, which can be used to advantage/disadvantage. With my tongue firmly in my cheek, I'd simply suggest more mfrs follow Rolls Royce, and describe power output as "adequate" that's how the RX-8 feels to me :p

As to fuel consumption, I am happy to post again my full data, from purchase now thru 21,000ks, showing a long term average of 12.2L/100k.

When I purchased this car, I certainly knew (a) it would be pretty powerful -- at least as much as anyone needs for high performance driving on our roads around the legal limits, and (b) that rotary engines were less economical than piston engines of the same displacement.

After almost 6mths, I remain a happly little Vegemite :D

Jaycee

I too am thoroughly satisfied with my RX/8. The power is as much as I need/can safely use, and the fuel consumption while not great is certainly within my expectations.

However, I certainly don't have any problems with people like Lock & Load pursuing these issues if they're a source of concern to them, and I'm happy for the progress/results of their actions to be published on this forum - let's hear the bad as well as the good about the car.

Lock & Load

jaycee

Thankyou for being open minded and not as **** retentive as some other forum members .

cheers
michael

jax8

Is it still that time of the month for you, L&L?

Gomez

Just thought I'd dust off this old thread.....

Hymee, with regards to the "safe mode" question....You may recall that last month I received a copy of the Yankee 2004 Service Highlights Manual.

I finally had a chance to have a good look through it, and spotted what is possibly the reason for the drop off in power at high RPM on the dyno...

Under the heading of Fuel Cut Control, it states that the PCM cuts fuel injection during continuous high engine speed while the vehicle is stopped.

The reason is to protect the cat from overheating....presumably with the car moving, sufficient airflow under the car would aid in cooling the cat.

The book lists other reasons for fuel cut also, ie, rapid decel, drive-by-wire malfunction etc.

Not sure if this helps in any way, doesn't answer why you're car is special....maybe 'cos red ones go faster :D :D .

Gomez.

Hymee

iTrader: (1)

Gomez,

There is a thread here in the Aussie section about the "Offical Reason From Mazda"... regarding the cars not being able to be dyno tested due to this safe mode. The reason is that even though the back wheels are spinning, the computer figures that since the fronts are not, then he car mustn't be going anywhere.

It doesn't seem to affect my car. It does seem to affect Wildcards car. They are the only 2 RX-8's I have personally seen on a dyno.

My silent partner has rigged up some equipment to get over the safe mode thing. We just need to test it on an Leather pack to check it's effectiveness. Stay tuned.

Cheers,
Hymee.