Hello, as some off you know I have a standard 4port manual 5speed rx8.
Here in Belgium they should make 192bhp at the flywheel.
I dynoed my car three times and every time it made about 162 bhp.
That's about 15% less than advertised.
Mazda Belgium know off my problem and have been asking mazda Europe and Japan for a solution. The engineer told me he has the same model and that his made 10% less power, so he knows this problem is for real and also told me that this is not acceptable. So far he had a visit from 2 guys from mazda Japan and they will look for a solution. Meanwhile he just gave his car to the University off Luik(Liege) here in Belgium, they are really known for anything that has to do with cars. They got 2weeks to get a solution otherwise mazda will make me some proposal.
I will let you know whether they succeed or failed.
(Sorry if my english isn't correct)

 

I'm assuming you dynoed it at the rear wheels, not the flwheel ...

 

Hmmm, how are you dynoing at the flywheel? Don't you have to take some things apart to do that?

 

Sounds like whp to me, but then again I'm a noob.

 

I dynoed it at the rear wheels and got 100kw or 140bhp, the loss between the engine and the wheels was about 23bhp so flywheel or engine power is 163bhp. Hope this makes things more clear.

 

If that is hp to the wheels that is easily within specs. HP to the wheels is usually somewhere in the range of 12% to 18% less than hp at the flywheel because of driveline losses.

 

The 162hp is at the flywheel, should be 192hp.

 

Just FYI, the people that have the 232 bhp models seem to dyno at around 180-185 rwhp. That means as little as 77.5% gets sent to the rear wheel. You're getting 140 at the rear wheels which is about 73%. That's not a HUGE difference. But if you can get Mazda to listen to you, go for it.

 

I know that your engines make around 180rwhp and you all seem to accept it. Here in Europe that doensn't fly, they will have to make the same number +-5%, so it's up to them.
I find it strange that in Japan they make 220whp with just a sportscat, cat-back and some changes to the ecu.

 

Man! I'd LOVE to have 220whp in my 8..
Thats almost double what I have now with my A/T!

 

Yeah, but the 180 whp is not reagular for a 232-238 hp car. Our cars are not really making those numbers. The accelration tests bear that out. We are making closer to 215-220 hp stock. Look at the 237 hp S2000 making 205 whp, or the 287 hp 350Z making about 240 whp.

 

The 220whp is made by fujitsa engineering on a 6port model.
We should see 180whp with the same mods.

 

oh boy, dyno racing season has started again

 

I'm pretty sure we have different measuring system (SAE) here in America than in Europe seeing as how you guys use the metric system and all. My guess is that we have different emission standards as well. If cars suffer x% loss from the flywheel to the rear wheels, there's not much that can be done about it. I'm sure Mazda isn't super excited about that much loss, but they have to balance government restrictions with reliability and cost.

Go America!

 

They should have thought about that before they published that number of horsepower.

 

Only problem is that in Europe the hp #'s should be higher. They are on a different standard, but that usually has higher numbers. For example, the 996 TT had 420 hp in European standards, here it was 415 hp, or their X50 car made 450 there, & 444 hp here, or the MBZ SL 65 is 604 hp here, & 612 hp there. The exception, the RX8 (manual) is rated at 228 hp (though that might change soon) over there, and 232 hp here. I actually believe the European rating far more than the North American rating. We have gone from 250 to 242 to 238 & now 232 hp. Emissions tweaking is a bitch.

 

Honestly I think it really might be a problem with your car. I had dynoed my car at a place (LA Performance Division) at 179 whp, and literally a few days later another RX8 owner I talked to dynoed on the same dyno & got 150 whp. He was talking to Mazda as he thinks there some definite issues with his engine. Good luck.

 

The main issue here is that they are using a chassis dyno to figure flywheel hp, which is ridiculous from the start. Can’t be done. The "coast down" they do to obtain the loss figure isn’t a procedure that could stand up to any scientific scrutiny to be used in court to prove the Flywheel numbers.

The only proper and legal way to obtain flywheel numbers is to remove the engine from the car and test it using the Standard that has jurisdiction in your geographical area. That’s SAE here in the states and DIN I believe in Europe.

 

He has a 4port 5speed model. Not a 6port 6speed.

Clarification in case anyone misunderstands Fanman's post:

The 6port 6speed US model never had 250 and was never rated with 250. That was a Target only. It never had or was rated at 242 either. It was rated at 247 at launch and was re-rated to 238 shortly after. The new rating of 232 is not because of emissions tweaking but because of new testing Standard. The power of a 6port 6speed 2006 US car is the SAME as that of the 6port 6speed 2004 and 2005 cars.

 

There's no legal recourse based on an assumption if that's what I'm hearing.

 

yup .

if you could see any real issue from looking at the Dyno charts- then maybe there is somethign to look into. KrisD can you post the charts?

 

Here's my dyno:
I also did a run on another dyno, with the same result.
The engineer at mazda Belgium had also the same result on another dyno.
eg. they also dynoed a mazda 6, and that got 4%more power than advertised.
He sayd he's not pleased with the result of the 8 and it should made the advertised number. There's no question about it that there's a problem with the engine. As told on the phone, the guys at mazda Belgium, Europe and Japan know that there's a problem otherwise they would have told me and didn't bother to look for a solution.

 

that dip near the top could be an issue ill need to look at some other dynos. what was the Torque result? is there a graph of that?

 

Actually I have the Mazda marketing brochure & in it they had the original Road & Track article where they stated from Mazda it was 250 hp, but on the cover they have a sticker with the updated 238 hp spec. You are right it is with the SAE specs that it is rated at 232 hp. Again, I am sketical of this hp rating. The dynoes & the acceleration tests don't bear out this (even the new) power figure.

 

250 was never the rated BHP of the US production cars. There are other places for this discussion tho- see my discussions with IKE and others about this.