RX-8 friend

That's kind of what we've seen too. Still not sure if it's RPM related as well as time or just time.

Yes, you can be in limp mode without any indicators. There seem to be at least three possible states of ECU unhappyness. BTW, it's called a "PCM" in Japan (and the manual), not ECU.

JimW

Thanks Judge: when I put more mileage on my car, it only has 500, and I get up the nerve I'm going to try it. It's interesting to note that your burnouts are more than 5 sec, which might put someone into limp mode, but your launches are less then 3 sec with the tires spinning, possibly preventing limp mode. maybe the limp mode activates with tires spinning and some load on the car as well, I take it your burnouts on the pad don't resist like a launch down the 1320, anyway great times in your car!

Omicron

Interesting. Thanks for the response Judge. Sounds like the car is not going into limp mode because there is some movement of the front wheels, even when the back ones are spinning. This would not be the case on a dyno.

bern

Guys,
What you have to remember is that Mazda did a fairly nice job of programming the DSC/TC system, to have a little leeway and not to be overly aggressive with cut in. You'll notice this same type of behavior on a road course. The car will let you play with some minor wheel spin and slide before engaging any appreciable manner. Now as how this applies to drag starts; I'm speculating that Judge Ito is coming just in under this safe mode threshold with his very precise launch and burnout technique. Of course above, I write about the DSC/TC being switched on, but I imagine, that the safe mode programming is very similar in operation and function with just a little more threshold involved to get the car into safe mode territory. It’s just one other thing to think of, and consider.

Nice job Judge Ito. Good to see that someone independent of Mazda showed that the time slips we posted at RN.Com were possible in the 8.


Cheers,

-Bern

GeorgeH

iTrader: (2)

Adding driver weight, for a total of 3200 lbs, yields 201 HP.

Upping the trap speed to 94 (Hymee's time) yields 208.

95.77 (Judge Ito) = 220.

So, there is room to believe in "missing HP." Not sure I do yet, but there is enough variation here to be far from conclusive.

George

rx8miami

what a discovery! but omicron do you think all those dynos were in limp mode? you think they never took it into consideration?

Hymee

iTrader: (1)

And to really throw a cat amongst the pigeons...

During some extensive dyno runs covering about 2 hours we found the car made MORE power when the "ABS" light came on. We reset it, and it made less. It was repeatable.

And here is the other rub - after 1 hour of dyno work we reverted to "stock" and checked against our baseline. With the car really "hot" we made something like 15-20 HP above baseline.

Would y'all be impressed if I gave before and after dyno plots comparing "not-hot & un-tuned", verses "hot & tuned" ????

If I did that, you might believe we actually managed to wring something like 20 - 30 HP out of it. But it just aint the truth, I am afraid.

My experience - for you to comprehend.

Cheers,
Hymee.

PS - Do you realise how open to critisism posting something like that makes me feel? It is a bit like putting your left nut up on the chopping block I wouldn't post it if it wasn't the truth

GeorgeH

iTrader: (2)

That's very interesting. I wonder what would have happened if you would have reset the ECU while the car was hot, at the end of the session, and then re-run your baseline. Could it be that the ECU is sensing lots of WOT usage and adjusting itself accordingly?

Out of curiosity, how warm was the car for the very first run? Fully up to "normal" opertating temp, I assume?

Hymee

iTrader: (1)

Yes - it was up to normal operating temperature before all of my "first" runs. The dyno cell we use is about 40km from where I live, and about 20 from where I work.

ranger4277

So.. how about posting up some of those dyno results? Pictures being worth a thousand words and all.

Hymee

iTrader: (1)

The final results I have posted at :
https://www.rx8club.com/showthread.p...5&pagenumber=5

Read the whole thread if you like - I don't skimp on information

I should overlay before tune-up "not hot" and after tune-up "very hot" comparisons. Then perhaps I could claim a 23HP gain (from 181 to 194). But I won't claim that, as it is not really the truth. BUT If I was a paying customer, and had gone in and seen the first dyno run, and come back late and seen the last dyno run, then I might be impressed.

Cheers,
Hymee.

PS - Maybe I should move the thread from Aussie to here??

islandsoon

Hymee, what you are describing matches up to what Chuck at Rotary Extreme reported over on the Air Intake thread with all his 'heat soaked engine experiments.

tessa

Can anyone Please help me. I have a 2006 rx8, with a magnaflow catback and a typhoon air intake. also have a unachip for it. I took my car to carbconnection in Kirkland WA to dyno it With all of these mods on my are in use and this guy Alex who is supposed to be an expert tuner, but know little to nothing about rx8s or rx7s told me my car dyno max was 165 and told me there was something wrong with my car keeping in mind he knows little to noting about my cars engine. He didn't even turn the DSC off on the the first run. I took my car to the Mazda Dealership and they did a complete check of everything. They checked the coils, spark plugs, ecu, and noting was wrong and told me the car is running beautiful after the mechanic test drove it to some extent. By the way according to Alex at Carbconnection the unichip dosen't work as well but he charged me $300 to tell me this.

Why would the Dyno be so low? Is it because of the ECU?
This place has little exp with Rotery engins.

Thanks Tessa:

shaunv74

Check out this thread. https://www.rx8club.com/nw-rx-8-forum-33/29-march-dyno-day-140698/

you should head down to these guys and see if they're still dynoing cars today. If so you could probably jump in with them. There should be two other RX8s there to compare to.

Either way you can't dyno it without turning off your DSC completely so you need to disregard the results until you get a clean dyno. Post up your printout or .jpg of your dyno results and we can see if it looks like the normal curve.