BHP/Power as Claimed, ongoing arguments
 

Hi to All

In the UK club site there is something of an argument between the technoheads.

Someone put a dynometer on the flywheel of a regular Hi Power 231 and it showed a horsepower of only 180 at max speed etc.

Some people are saying that mazda has lied about the HP. Other racy types are saying that they have been wooped by Audi TTs and lesser automobiles.

Apparently all cars lose 10 pc of HP by the time the wheels spin on a road to make it go.

A couple of us were wondering if our cousins over there had any take on this???

Sorry I didnt post this to the highly tech thread, but if it is an issue, it may concern everyone...............is there misrepresentation???

I love my RX8 but the point would seem to be interesting...


Paul

Put a dyno on the flywheel? Did someone actually take the engine out of the car and stick it on an engine dyno? It sounds like the car was placed on a chassis dyno. Those numbers are very close to what is typical here in America. The results will vary some depending on if it went into limp mode or not.

It's kind of split, some don't believe the car is making the new advertised number of 238 and probably 220ish at the crank is closer, others feel it is making the 238, and then there are those that just don't care.

Try doing a search. There was a pretty long thread on this a couple of months ago with lots of results posted. Beats me though.

Why would mazda lie about the 238 hp? They should know that we would all return our cars. I don't think there is reason to doubt that number.

That's a joke right? If it's not it's still very funny :p

Well i meant it would be bad if they lied TWICE!:D

I believe inthe US the manufacturer has to be within 5% of the stated BHP?

5% off 238 is 226bhp. Very similar to UK spec BHP.

Thread he's taloking about on uk forum is :
http://www.rx8ownersclub.co.uk/forum...pic.php?t=1729


181.7bhp at the wheel, a rare uk dyno chart. I belive US cars make 170-190ish?

They should just put the motor on a dyno, that way they measure the flywheel HP.

today this show called tuner something was on the speed channel and they were modding an 8. they dynoed it; i cant remember what it made but 180 sticks out in my head so it might have been near that. the show really sucked so i didnt pay much attention.

Do you realize this would mean a 25% loss through the drivetrain?! Either the dyno tests are inappropriate for whatever reason, or Mazda isn't being entirely truthful with us It would seem to me that a lot of unnecessary friction would be required to explain a 25% loss. I for one find the car to be adequately powered for me, so it doesn't really concern me , esp. since damn is that engine smooth.

Regardless, here's Edmund's take on the subject (decided to google this subject before submitting the post)


"
Obviously, another factor to consider in this discussion is how accurately the manufacturers rate their own engines. It's hard to believe that the Corvette and Neon could lose 17 and 22 percent of their engine's horsepower in just frictional losses. Most experts agree that a 10 to 15 percent loss is normal. This does not necessarily mean that the manufacturers are lying. The additional drop could come from a number of causes including variations in engine performance and dynamometer readings. It could also be that the manufacturers are dealing with an expertly tuned engine's running under controlled conditions in a laboratory rather than a mass-produced engine that was put together on an assembly line and sold at a dealer's lot.

Whatever the cause, it's important to remember that there will be a loss of horsepower between the engine and the rear wheels. Since most manufacturers advertise a vehicle's net horsepower rating, the number quoted in all the magazine tests and sales literature isn't necessarily how much you're going to have available for shooting away from stoplights or climbing up mountain passes. Keep that in mind the next time you're scanning spec boxes. If you really want to know how powerful a vehicle is, test drive it. If you're looking for an accurate horsepower figure, a dynamometer run is the only way to know for sure.
"

I fully believe that the real number is somewhere around 220-225 for the american region fuel map specs. Most of the Dynos on this site were not performed at sea level but even adjusting for that they rarley hit above 190 at the tires.

Does anyone have a Japanese spec Dyno? I would be intereseted in seeing a side by side of all the different tuning maps for the regions. I know Canzoomers mod is supposed to reflect the original ECU maps for the japanese tuning... just curious really.

I tend to agree with the 220-225 figure - the numbers produced in the magazine tests seem consitent with a 3000 lb car with about that much power. Albiet, that's with dumping the clutch at 7500 rpm and with the relatively high final drive ratio in the 8.

So, where that leaves us is YES, MCNA lied to us not once, but twice (three if you count the Miatas). What we have is a demonstrated willingness by Mazda to lie to it's customers. Given this, who's to say that the EPA numbers are to be believed - considering the low mpg that it seems most are experiencing? They probably hedged the HP numbers again because dropping the rating from 250 to 220 or so would have caused some MAJOR backlash. What's 12 HP compared to 30 or so, right?

Now I can't complain too much because I bought my car after the 238 HP restatement and after driving the car. And I still LOVE the car. But I am seriously miffed about being lied to. I don't see why we couldn't obtain documented proof of the true HP figures and stick it back to Mazda with a class action again.

Put it another way: how many of us would have kept/bought (before/after buy-back period) if Mazda had sold this car with 220 HP and 13/17 EPA figures? I don't know if I would have . . . for that kind of gas mileage I would expect well over 300 HP!