compaddict

Raw Data: (right click, save as, all files dynonrun.001)
http://www.compaddict.com/RX-8/Dyno/DYNORUN.001
Raw Data from a stock 1994 RX-7: (right click, save as, all files stan.001)
http://www.compaddict.com/RX-8/Dyno/STAN.001
Run viewer software to see the data:
http://www.dynojet.com/downloads.shtml
7-30-2003
2004 RX-8
6 Speed w/sport
DSC & Traction Control Off
35PSI tires (Cold)
95 degrees F
22% Humidity
2215 miles
Third gear pull
100 Ft. Elevation

9-04-2003
2004 RX-8
6 Speed w/sport
DSC & Traction Control Off
35PSI tires (Cold)
85 degrees F
32% Humidity
4525 miles
Third gear pull
100 Ft. Elevation


Fourth and fifth gear runs were about one percent less (normal variances between runs).
I have over a hundred runs on this dyno with my other car and it seems about right with other Dynojets with comparable cars.

Vince

zoom44

what is the spec sheet hp of your other car and what has it dyno'ed at on average in the 100 tests?

just looking at this graph i would say everything looks correct, except of course the peak HP. the 3 ports open at the correct rpm's and max power is at @8500 which is where it is supposed to be. it's just too low. i haven't commented in the dyno threads yet but i think now i am starting to agree with the fuel mapping people. otherwise i would have to say something is seriously wrong. i just don't get why this fuel mapping switch bit wouldn't be in the owners manual. was it in the "tech highlights" cd? i haven't burned and watched it yet.

seikx8

It is me or The TQ graph > 6200 rpm seemed a little bit odd?

compaddict

The other car is a CSP Miata and its output is coincides with other CSP Miatas with the same state of tune.
This Dynojet is as far as I can see the same as another Dynojet I ran the CSP Miata on one month before I switched dyno shops.

Vince

compaddict

Nope, it coincides with the secondary port opening.

Vince

Digisan

Wow, this doesn't look good. So far all of the dyno runs that I've seen are ~180HP at the wheels. That's 25 HP less than Mazda stated. I asked my dealer if he could find anything out, I doubt he will.

D-san

Quick_lude

So what do you guys think? At which point can we expect the fuel maps to change and "release" the full power of the engine? Is anyone going to bring this up with their dealer/sales rep/regional rep?

Vince, have you done any 1/4 mile runs yet?

Digisan

Well, I paid for 205rwhp or 247 at the crank, and that's what I want! I haven't opened it up yet, but I may be disappointed when I do. Mazda needs to start talking right now before I start getting irate. Don't get me wrong, I love the car, I just want everything that I paid for.

Any of our Japanese friends put one on a dyno?

D-san

BOOSTD 7

About all I can think, is this BLOWS! I'm sure after these recent dyno's, this car is going to be the laughing stock of all the forums.

MrWigggles

It is clear to me that the car for whatever reason isn't making the power it is supposed to after about 6K.

Those ECU maps need to kick in.

-Mr. Wigggles

compaddict

I think the whole changing fuel maps thing is total speculation and at this point in time no one but Mazda knows why the HP is down so much.

I don't do 1/4 mile stuff but I autocross and my RX-8 seems fast enough!

Vince

Quick_lude

Well if that run that was done with the G-tech is any indication, lower gear power is not a problem since he did pull of a mid 6 sec 0-60.. but the power up high seems to be lacking thus the mid 15's 1/4 mile time. I think everyone expects this car to dyno somewhere in the 200-210 whp area. Assuming for a min that the dyno numbers are off for whatever reason, DSC, etc, but if the car only does mid 15 in the 1/4 then that supports the 180whp numbers. The mystery continues...

BOOSTD 7

I think it's unrealistic to think a switchover in the ECU mapping will suddenly find that 20 - 25 horsepower. And even if it does, having to wait until 20K miles would be seriously frustrating.

Quick_lude

Especially since the car magazine mules were pulling off mid 14's with 2-5K miles on the odo..

neit_jnf

Actually, the secondary opens around 4000rpm, that one is the auxilliary/ tertiary port.

Is there a way to see a Torque curve from this data?

compaddict

You are right of course!

To look at the data download the runviewer software and then open the files and select "Torque" by right clicking on where it says "SAE Horsepower" and if you want "RPM" instead of "Speed" do the same right mouse click trick on it.

Vince

Kawi

Let's try this too:





You can click on the image for a larger more easily read version.

compaddict

Kawi: Do you have the full version of WinPep? Or am I missing something? Or both!

Vince

Kawi

Nope. I just downloaded the executable that you posted from above.

The scales on the left and right sides of the window have options you can right click on and change.

Quick_lude

So what do the two dips at 6.4K and 7.4K represent? They're rather large and the torque is definitely decreasing after the 6.4K dip. Did you "feel" those dips in power while on the dyno?

Doctorr

Maybe it would be a good idea to run some '8's around the country until they had a quick '15 thou' on them so a realistic dyno could be done.......Oh, yes, Mazda felt the need to do this already, but they aren't talking................
.
.
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doc

compaddict

Thanks I didn't see that and I have using Runviewer for a while!

Vince

neit_jnf

Those are the ports and variable intake paths opening. There's a slight dip @ 4000 which is the secondary port opening, then the tertiary @6300 and fresh air duct and variable intake path @ 7500

Those dips are also visible on the other dyno chart in another thread

The Beav

that torque number seems to be way down, preportionally to where the power is down, that's where we should be focusing, now i'm kinda scared about my order, have we got any dyno charts from teh jdm models

MrWigggles

The torque numbers (and hence the Horsepower) are pretty good up to 6000 RPM. about 18% lower at the wheels than Mazda's claims for power at the flywheel (15%-18% drive line losses are considered standard). It is after that where power numbers are considerably lower. Attached once again below is the Mazda torque curve from the press-kit (1 nM = .74 ft-lb). It is the power at 8500 which is supposed to be 153 ft-lb and is only about 111 ft-lb. That is 37.5% reduction in torque (and thus 37.5% reduction in power.) So at the highest RPMs the car is down about 20% more than what could be attributed to drive line losses.

So on a 0-60 run where you are probably going to be between 6000 RPM and 9000 RPM to create the fastest run. The car is going to have about 10% less power than it should. Which means you are going to be about 10% slower than you normally would be. That is why Car and Driver did 0-60 in 5.9s and the best claim so far from new owners is 6.6s (I believe)

Bottom-line: Mazda, at some point we need our 20% of high RPM power back.

-Mr. Wigggles

Ps. just a reminder that horsepower is derived directly from the torque curve: HP = Torque X RPM / 5255. The two are completely inter-related and that is why the ft-lb of torque at 5255 always equals the horsepower.

eccles

Something ain't right here. The dips as each extra port opens, suggest that the engine is spinning up too fast for the newly-opened intake paths to "catch up". I wonder if the results would be different on a variable-load dyno which would allow the system to stabilize at each point in the range. How long did it take to do these 3rd-gear pulls? Has anyone done one in 5th yet?

RX-Nut

Well, if we all were deceived, that's just wrong. I mean every other forum I browse just about says the 8 is all looks no go.. That's beginning to be it's rep..

It's getting obvious that all these dyno runs and such are on the money. They flat out tell us that we're not getting what we thought we would..

I wish Bern from Rotary News could chime in and ask his chums at Mazda.. Or someone.. there's got to be some source we can confirm or deny with.

Digisan

I agree Nut, time for damage control!

Digisan

Did I mention ASAP!?

kostas*

I think the dyno results are not important. The only think that really matters is how fast the car is. If you can achieve 0-60 in 6sec with only 180 rwhp it is fine by me.

Digisan

I think the dyno results are very important. I want what I paid for, which is fair. I'll give them the book and the mug back for the 25 missing HP.

MrWigggles

No one has been able to do that yet. I think the more aggressive fuel maps will kick in and allow for that, but for now that isn't the case.

Yes, ultimately acceleration, top speed etc are what's important.

-Mr. Wigggles

kostas*

I was only implying that because of the sometimes deceiving nature of the dynos we should focus at the road performance of the car. Of source we all want to get what we pay for, but first we must be 100% sure that we KNOW what we are getting.

RobDickinson

Hmm is it me or shouldnt the extra ports open BEFORE the drop in power?

2nd Should open at peak power @ 6250 instead of 6500
3rd should open @ 7250 instead of 7500?

Also if running rich then its a bad fuel map, which Mazda MUST have spent a long time working on.

Having the ECU change charictaristics at a certain milage should be mentioned in the owners manual, something like 'Car runs rich/low power until xxx miles' and def should be eithe rhidden or high milage (10k+).


This looks bad, esp for us euro's who only get 228bhp to start with.

86rx7

thats not a drop in power due to not enough intake, thats a loss caused by turbulence as the motor is switching intake configs. Also all second generation rx7's had a mileage switch that ticked over at 20k miles, and i dont ever recall seeign it in the owners manuel.

RomanoM

You know just for chuckles I'd love to see what the torque curve for the low power (207bhp) engine look like.

I know apples and oranges, but just for the hell of it.

Anyone?

loco4rx8

After reading all of this, my question is:

If this data is correct and Mazda will admit the car is missing some promised HP, is there a way they can "fix" the problem on the cars that have already been manufactured?

ChrisW

We have already had the power officially reduced to 228 hp in Europe. If we actually only have 200 hp for the first 20K miles (which is three years for me!) then I will give this car a miss.

What happened to the 250hp/155 mph sports car that I read about only 12 months ago?

pelucidor

The only cars that did 0-60 in 6 secs were the pre-production ones reviewed by C&D, R&T, Motor Week etc which probably had full power.

The production cars might be relatively slow, as evidenced by the Best Motoring video from Japan where everything but a Miata passes the RX-8 and the driver wonders where his 250hp is (I am paraphrasing)...

What, if anything, changed in the engine between pre-production and production? Can a Mazda employee (budaman, lfubar) find out?

compaddict

I'm quite happy with my car just the way it is. 180 HP at the rear wheels with a flat torque curve and a 9000 redline makes for a very nice ride.

One of my other concerns is am I paying to insure a 250 HP car or a 220 HP one?

I have included a dyno run from a stock 1994 RX-7 on my original post for comparison.

Vince