6speed8

In the new Car and Driver (May 2004 pg 128) there is an interesting article titled 'Is your Dyno lying?'. The article mentions the usual 15% loss for manual transmission cars, BUT some losses have been seen as high as 35%. Steve Dinan (of Dinan BMW fame) reports on how one of his 2003 M5s was heavily tweaked to make a claimed 470 hp (which would be 415 at the rear wheels), but with the hood closed and a fan blowing on the radiator produced only 334 hp.

Then with the hood open and a Home Depot Shop fan blowing 10 mph air, the HP goes to 371, close, but still not right.

Dinan then brought out his $7,000.00 turbine fan that blasts 38,000 cubic feet of air at 75 mph down a narrow duct right into the radiator and gets 411.4 hp.

The article mentions how cars are gradually becoming too computerized for the simple dyno test. It mentions how the battery of sensors that report when airflow over the bumper is not enough, the air inlet is too hot and the engine water temp being too hot. The computer backs off the spark and turns up the richness, which reduces power and keeps a catastrophic engine meltdown from occuring. (sound familiar?)

All in all the C&D article (which does not mention the RX-8) appears to completely back up the claim of not getting the true HP reading on the RX-8.

It's interesting reading, and hopefully will shed light on those still in the dark on this subject.

XDEEDUBBX

very interesting

draco067

Interesting to say the least ... but is there an airflow sensor somewhere on the 8 that would account for this? I had assumed that most of the essential electronics would have been discovered by now. How else could the ECU know to pull power?

cortc

I have driven many cars in the past including my last a 1999 996 C2, I have no problem with Mazda's revised number of 238 HP and I believe this is conservative... With a few tweaks and mods she should be at 250, no problem...

wakeech

like (with only) the Canzoomer or Greddy E-Manage...

r0tor

iTrader: (1)

it can be theoretically back calculated from intake manifold pressure... back in the few years of the traction control being banned in F1, the engine management computers would do this to guess when you were spinning the tires.

Broker73

you best me to it !

I just read the article in the airport on the weekend, and it sums up what many on here have tried to dispute. I don't think the car is that low in hp, and can't be compared to other vehicles......who knows what the computer does, and how it affects dyno results.

The part about the M5 tells the story, so hopefully people will think about that before crying that the 8 only dynos at 170ish

madsenj37

Its good to know that Mazda is not the only company that sticks by its claims if this is the case. Its the 0-60 and quarter mile times that matter to me the most. HP and torque are good to know, but as long as the 0-60 is good, I am happy.

lil benny 237

question...
What is the Greddy e-management?

can you use it with the CZ mod?

D3G

Im with you on that one.

kbull

HP and torque are bragging numbers. No one ever boasts slalom times, although 0-60 and 1/4 mile get plenty of attention. There are too many factors that go into a car's overall performance. You don't get a good picture of the car by it's HP and torque, you get a good picture by driving it.

RotorManiac

That's what you call 'handling'. Weight distribution, suspention set up, everything! Little things the 8 has perfectly arranged! And not only driving it on public roads but also driving it in a curcuit helps you to truly explore the capabilities of the car. Do that and you'll realize the 8 corners much faster than many other great cars.

MazdaManiac

iTrader: (3)

They are two methods of achieving the same result.
See my write-up HERE on the Greddy E-Manage.

Ktreece777

The car was an 03 man why would it not have it when ours would