Excellent. Thanks Jon. We can all take a breath now.

So...who won the bet?

 

so I take it the you did both 3rd and 4th gear pulls. Philodox hit 240rwhp on one of his 4th gear pulls. How many minutes did you take between runs to have the engine cool? Also, was there a fan blowing on the engine? If so, was it a small fan or some big jet fan like the one dinan has?

 

I think we have a winner in the guessing pool for dyno results

 

I did all my runs back to back to back.. maybe 1-2 minutes between each run. The 4th gear pull was the 2nd to last run. I posted the last two runs I did in a post just a little bit ago. They had 2 fans, one blowing on the IC and the other was a huge monster going over the whole front of the car.

I have to go out for a little bit guys.. be back in a few hours.. hopefuly Jeff can field a few questions while I'm out

 

Let's see how the math works. note my prior calc of the density ratio of 1.388. Or 1.388 times the base. So Jon says he had 174 hp before so 1.388 X 174=241.5
This isn't the final word but it seems to work.

It also shows that guessing by pressure does not work and that was the lead argument.

 

Okay, I took the first dyno, estimated the hp numbers to about the nearest 5, used 93.3 mph in 3rd gear at 9000 rpm, and this is what I got.

I also assumed 5252 was the torque/hp factor. Do I remember correctly?

Source for 93.3 mph:
https://www.rx8club.com/showthread.p...onomy+gear+rpm

Enjoy!

~ Matt

*** EDIT *** I took a closer look at the 93.3 mph post and I think it isn't right. Let me know the real number and I'll update the spreadsheet.

*** EDIT #2 *** I tried searching, but couldn't find the right number. Now it is time for me to go home, so someone else will have to finish it. Still, the numbers look reasonable.

 

Big swamp-boat sized fan.

I never did a run in 4th. In Jon's case, it netted a slightly higher power figure.

I spent most of my time (all of it, actually) just tuning. I didn't look at the peak HP numbers until I started to get the A/F right.

 

Thanks for the report Jon and Jeff... I'm really impressed with this Greddy kit now. That's one fast RX8! :D

 

Interesting..

Do you folks trust the dynos numbers even with its inability to read RPMs and the RX-8's history of poor dyno run results?

 

^^^I would trust that they are making at least 225 and 240rwhp. If there are issues w/ the DSC kicking in to cut the gas (since front wheels are stationary and the rear wheels are going at 10+ mph faster), then they are probably really making more than what the dyno reads.

 

WOW, thanks for the info...and now to 0-60 & 1/4 mile times...

So, we have a (probably) 300HP RX8 or 240whp...wow!

 

No!! Take it to the track guys against a stock RX8!!! :p I wanna know how fast the beast is.

 

Yea, that's what I'm hoping.. but regardless those are still pretty damn good numbers dont get me wrong.

Way to go guys.

Now if it can be tuned to remove the popping richness and possibly even result in more 'oomph'........ hhmm

 

is it cutting gas or adding gas to be fast and rich?
Since he has the A/F ratio on the graph, if your near your target A/F ratios of 12 to 1 or whatever you're shooting for and you make 225 or 240...then that is what your car makes to the wheels. No dyno crying or making excuses about it. If you tune for 12 to 1 and your dead on it, you can't blame it on the stock ECU and the DSC or try and say you'd be making more if isn't wasn't for this or that kicking in.

with the greddy kit, can you adjust timing any?

Tim

 

^^^relax guy. no crying by anyone on these dyno results. Philodox got 60+ horses to the wheels from his Greddy Kit. Maybe the DSC kicks in and he could be making a little more if it doesn't...maybe not. Nobody is complaining at the results. take a pill man.

 

I think 60rwhp is what Greddy was claiming it makes so spot on. Nice numbers. It must be a fun ride.

Cheers.

 

umm what's whp without the turbos again?

 

Philodox baselined at 174rwhp or so. most dead stock 8s will baseline at around 169 rwhp. Of course there are some stock 8s that will dyno higher or lower.

 

No DSC. No limp mode.

I ran the CanScan as we dyno'ed and there was nothing odd about the ignition timing or throttle.
We did NOT pull the rear wheel sensors.

The myth about dynoing the the RX-8 is busted.

There are only three ways the RX-8 could do anything like a limp mode:
1) Pull throttle
2) Pull ignition timing
3) Add a LOT of fuel (though, really, that wouldn't do much but make the car run like crap)

After 16 consecutive dyno runs - the last 11 without turning off the ignition at any point - nothing like the above ever happened.

 

This is for sure...the 8 will only get more toy's built for it with time, the ECU will be figured out, turbo's/sc will get better, add on's will get better, and our car will become a near perfect sports car!!!

 

65HP is great, but and I hate to say this...it appears that either the rotary is hard or does not dyno right, 27% loss (Flywheel hp to whp) is normal/standard for a rotary, or our 8's make less than the 238HP Mazda tells us.

Not to nock our great car...I'm just saying, but does anyone know what loss the RX7 rotary had...or what whp it made? I just wonder about that heavy 27% loss....

 

RX-8s dyno out to 160 or 170 WHP.
Experience shows that nearly all vehicles exibit approximately 17% loss from rated power figures.
This puts the flywheel HP around 200, which matches the performance exactly.

Now, I hate to call Mazda a liar, but...

 

It's already been told so I'm not breaking the news. It makes 212 to 219 BHP at the crank.

 

It has been demonstrated for a long time that the RX8 does not make 238HP at the flywheel... more than likely it's between 210-220hp.

 

What would you believe.....really unreal drivetrain losses........25-30%

OR that Mazda has a very unreal Dyno :D :D :D