...when you did it, did you tie together the sensors that sense the wheels are not all moving and put the car into "limp home" mode?

If not, it's beginning to look like your results are going to be way low, as limp mode severly retards engine power via the ECU. See this thread for more details: http://www.rx8club.com/showthread.php?s=&threadid=16738

Something else to consider: If a good burnout does indeed also put the car in limp mode, then any of our 0-60 and 1/4 mile times are going to be less than the car is truly capable of... stock... including the test results of all the car magazines. So 0-60 in 5.9 sec and 1/4 mile in 14.5 secsonds may be slower than the car can do with nothing more than a simple sensor-defeat mod.

Interesting, no? :)

hmmm... anybody know what he is talking about? sure sounds good though ... i hope you are right!

The car has wheel speed sensors on all 4 wheels. They are used for the ABS and DSC. You can turn off the DSC when you want to race, but the sensors are still active (for ABS). Every major system in the car talks to the ECU (EPS, ABS, DSC, etc.). If the ECU is told there is a problem it goes into "limp mode" (lower power output and perhaps even poorer mileage). This mode is triggered when you spin the rears for more than 3 or 4 seconds, in a burnout, for example. To reset it you have to turn the car off and restart it. This also affects the car when on a dyno.

We are working on a module that racers can install that will fool the ABS into thinking all wheels are spinning at the same rate. I say "racers" because this is potentially dangerous, and should be done by experienced racers only. Prototype should be done this week. More on this later.

I think it's great a fix for this is in the works. But what blows me away is the impact this discovery may have on both dyno output AND performance stats, and that this little fact has not yet been discussed extensively.

Check out the 'Hymees cat back' thread in the Aussie forum, they are finding the same thing.....

S

I really don't think that it will best the 14.5 times etc. I've got extensive 1/4 mi drag racing experience( hence the name) and this feels like no faster than a mid 14 sec car. BTW I am both big and asian.

Originally posted by BigAsian
I've got extensive 1/4 mi drag racing experience( hence the name) ... BTW I am both big and asian.

So if your name was BiggerAsian or BiggestAsian, would that give you more experience? How does your name give you extensive 1/4 drag racing experience??? By the way, drugs are bad.

I am Big Asian, end of story.

I don't see how 0-60 mph times of 5.9 and 1/4 mile times of 14.5 could have been achieved in limp mode. Those have to be true numbers.

Is there any way to tell that the car is in limp mode, ie a CEL?

From our experience yesterday, the car does not throw a CEL.

The DSC light goes off AND the ABS light comes on. The wiggly line symbol stays on. Turning off the engine and re-starting did not reset. We had to back the car off the dyno, drive a short distance (20m or so), and drive back on the dyno.

I am amazed on the comment "But what blows me away is the impact this discovery may have on both dyno output AND performance stats, and that this little fact has not yet been discussed extensively" (not being critical). I have seen thread about this for a while:

http://www.rx8club.com/showthread.php?s=&threadid=11614
http://www.rx8club.com/showthread.php?s=&threadid=11656

I tried to think it was BS at first, but am always happy to be proven wrong. Looks like I was.

BTW - A word of warning for the uninitiated. I am not calling anyone on here a liar or unscrupulous. But I must say it is very easy for a dyno operator to fudge the power reading by the small amounts (<10kW)that have been reported for cat-backs. In fact, I read an article in a mag yesterday and they showed how they could fudge 50kW between runs without altering the engine at all!

I prefer to use an independant dyno operator for my exaust runs. For tunes it is harder as a Tuner needs a dyno to do his work, so he is also my Dyno man. I trust him though.

Cheers,
Hymee.

So being a big asain your like 5'9"??As far as performance numbers go,if you spun the tires long enough to throw into limp mode your time would still suck.Now dyno thats another story.

All this HP and dyno crying is getting old.. Just accept the fact that the RX8 is a low 15 seconds car and a high 14's car if its properly launched with 8000Rpm clutch bomb..

Nice Hymee,

I just recently had my car dynoed and only came up with 179 whp and 135 tq on SP engineerings dyno.

Now only if we knew what percent of the actual power was missing. Im thinking its retarding the timing and adjusting the fuel up to a set maximum ammount since we all seem to be falling in the same ranges. I could be talking out of my arse tho too its just a thought. I just wish we had an "valid" us spec hp number to use to figuire stuff out with. Not some magical number Mazda decided to pull out of their arse.

Thanks for the info tho its very much appreciated.

Originally posted by 350z Driver
All this HP and dyno crying is getting old.. Just accept the fact that the RX8 is a low 15 seconds car and a high 14's car if its properly launched with 8000Rpm clutch bomb..

I think the crying is over........what has been brought to attention is people want to know how much hp they really have.

We want a valid baseline as im sure you did when you got your Z. I know i do thats for sure.

I guess we could base it on times at the track but then that would mean on the track the M3 350z and the RX8 all share the same times stock.

Now that cant be right can it Mr Z?

wow...this could be scary...even for Mazda..."lies, lies, lies" as the Thompson Twins so eloquently put it...oops...showing my age there....

I thought that this was settled by canzoomer a few months ago?

Vince

Originally posted by compaddict
I thought that this was settled by canzoomer a few months ago?Yes, a few months ago Canzoomer discovered this, but did not do too much investigation. All of us who followed that thread apparently missed the implications of this limp mode thing too, myself included, until recently. Now that it is coming to light, we may have a VERY simple mod that will yield significant results. Time will tell.

I thought it was settled as well, but it come to the fore again.

Be wary of using a dyno run in isolation to give you an absolute indication of your engines capabilities. A dyno is tool used by tuners to determine relative changes in performace characteristics. What I mean to say is even though your car pulled 170rwHP and mine pulled 160rwHP does not mean a lot, as there were measured on different equipment.

I am starting to believe the "safe mode" theory. As explain by the "Offical Mazda" explanation, the computer dumps in extra fuel as one of the precautions. We have verified that on the DynoLog chassis dyno via the wideband O2 sensor. Up top the mixture went rich, and then a corresponding power drop.

I posted the below thoughts on a couple of related threads, and have repeated it here for the benefit of those who might miss it...

I have been thinking (maybe that is a bad idea :eek: ) They (Mazda) say the only way to measure engine power is on an engine dyno. That part is correct. But on an engine dyno you still need your ECU hooked up, as it is what is controlling what is going on... So what about the wheels turning etc... when they are not even there? Then it hit me like a light bulb. Are you thinking what I'm thinking???

Instead of fooling the computer to think the front wheels are going the same speed at the rear wheels - why not disconnect the rear wheel sensors, and make the computer think the rear wheels are going the same speed as the front - 0 RPM???

Worthy of injecting into the discussion I think!

Cheers,
Hymee.

Originally posted by 350z Driver
All this HP and dyno crying is getting old.. Just accept the fact that the RX8 is a low 15 seconds car and a high 14's car if its properly launched with 8000Rpm clutch bomb.. Mr 350Z Driver, thank you for your charming and constructive response. You are certainly doing a beautiful job of contributing to this community.

Based on this response of yours I have to conclude that you either (a) do not understand the issue, or (b) are deliberately trying to start a flame war by making inflamatory statements. If the former, let me explain the implications of this again:

(Do burnout to get best 0-60 or 1/4 time) = (Car goes into limp mode)
(Limp mode) = (Drastically reduced power output of the engine)
(Drastically reduced power output of the engine) = (poorer 0-60 or 1/4 time)

Your statement that the car is a high 14's car is based on what? What you read on the internet? What someone else told you? The car magazines test results? Or even more credible, actually seeing slip times at a race event? REGARDLESS, all of these tests would have been done with the car in limp mode, and the resulting retarded power! Without limp mode, the power would have higher and the times better.

Get it now?

On the other hand, if you are indeed trying to start a flame war, that will soon become obvious and will be dealt with accordingly. Consider yourself warned. Or you can just save us all a lot of trouble and let me know right now.

Thanks...

Originally posted by Hymee
Instead of fooling the computer to think the front wheels are going the same speed at the rear wheels - why not disconnect the rear wheel sensors, and make the computer think the rear wheels are going the same speed as the front - 0 RPM???

Worthy of injecting into the discussion I think!

Cheers,
Hymee. Good thought, but as I recall, Canzoomer tried this first but it reported error state and and threw a CEL. He had to connect the sensors together to bypass this problem.

Originally posted by Omicron

Your statement that the car is a high 14's car is based on what? What you read on the internet? What someone else told you? The car magazines test results? Or even more credible, actually seeing slip times at a race event? REGARDLESS, all of these tests would have been done with the car in limp mode, and the resulting retarded power! Without limp mode, the power would have higher and the times better.


I have seen 3 RX8's run at my local track in near ideal conditions, traction control fully off and they concider themself good drivers and not seen 1 do better then a 15.18@93mph with a 2.11 60' in a combined 8+ races watched.

Thats a far far cry from a 14.5, people spend hundreds and sometimes thousands to get .7 in the 1/4. And this is with a 2.11 60' so its not a launching error..

I am actually giving the benefit of the doubt saying high 14's, given a perfect launch and a near a near perfect 2.0 ish 60' its attainable.

And the limp mode theory when doing burnouts etc just makes me laugh. Looks to me llike you people are reaching for anything that resembles hope.

Originally posted by 350z Driver
and they concider themself good drivers


...and that means what?? who doesn't consider themselves a good driver, be they good or not?? obviously no one who actually drives would want to admit that they're not very good, especially those who take so much pride in their car that they take it to the track adn try to perform...

I am a good driver! ;)

guys, there no point trying to reason with 350Z. He thinks he is an expert on the 8? The Z is a nice car, but I don't think I would spend any time over on their site just to bash?
With a simple ECU mod (Canzoomers stage 1), I am sure you will see the 8 put down some great times! Might surprise a few Z drives out there.

Originally posted by 350z Driver
And the limp mode theory when doing burnouts etc just makes me laugh. Looks to me llike you people are reaching for anything that resembles hope. You just don't get it, do you? Look at it one more time:

(Do burnout to get best 0-60 or 1/4 time) = (Car goes into limp mode)
(Limp mode) = (Drastically reduced power output of the engine)
(Drastically reduced power output of the engine) = (poorer 0-60 or 1/4 time)

(Hint: The reduced power output is key here)

"...reaching for anything..." ? I think not. Looks to me more like you are reaching for anything to slam the '8.
Be gone, troll.

Hell i go over to the Z forums sometimes because im really interested in the car and try to learn more about mine by visiting the Z site.

There are so many Z owners on the board with very honest valid and constructive things to say. It just pains me and irritates me to see someone talk so much ignorant crap without even trying to understand the situation being discussed.

Nissans had their share of weird crap like the ECU that tunes down your car after adding mods very noticiably. You dont hear Mazda owners going and saying BS your car just sucks why do you even bother modding.....because it doesnt suck and you all figuired out how to fix it and i think thats awsome.

Cars have alot of weird crap that needs to be figuired out. I acutally appreciate your interest in our car it shows no matter what you might say we have piqued your interest so much that even though its such a useless topic to you its good to see your still interested enough to keep checking in.

The more parts of the car the ecu controls, the longer and more difficult it will be to study and then devise a modification for. We are still 2 weeks away from driving the RX-8 in the same model year that it is desingated as! It's twice as difficult when the manufacturer messed up in the first place in regards to the ecu. If the RX-8 weren't capable of any more performance from proper tuning then Canzoomer wouldn't be getting a tremendous gain in power right now. Wait until the ecu is tweaked even further. The engine still has more in it then even he is getting. Then we still have bolt ons. 2004 is going to be an exciting year for RX-8 performance and I guarantee that at this time next year there will be some people that will have to eat their words in regards to the potential that the little Renesis has. The Renesis is far and away superior to the older rotaries and we know how fast you can make them. Just wait until porting is figured out and forced induction is worked out. This car is going to turn alot of heads.

Here's a good comparison of how a truly good sports car is the sum of its parts and rather than a single strength. After reading this then consider what proper ecu tuning will do for us.

http://www.edmunds.com/reviews/comparison/articles/101039/page002.html

Originally posted by GooOnYou
I don't see how 0-60 mph times of 5.9 and 1/4 mile times of 14.5 could have been achieved in limp mode. Those have to be true numbers.

I agree...if you use a horsepower calculator and enter the quarter mile time, trap speed, and the weight of the car, it shows the "true' 238 horses. So I find it hard to believe that the WHP is really as low as everyone claims. So in light...I believe that the limp mode is affecting the chassis dyno results, but I doubt it'll help the actual quarter mile time that much more.

Originally posted by 350z Driver
All this HP and dyno crying is getting old.. Just accept the fact that the RX8 is a low 15 seconds car and a high 14's car if its properly launched with 8000Rpm clutch bomb..

Umm...ok?

We weren't crying that the numbers are low. We are just saying that there might be a reason that they are low. There is a big difference.

Originally posted by zerohour
Hell i go over to the Z forums sometimes because im really interested in the car and try to learn more about mine by visiting the Z site.

There are so many Z owners on the board with very honest valid and constructive things to say. It just pains me and irritates me to see someone talk so much ignorant crap without even trying to understand the situation being discussed.

Nissans had their share of weird crap like the ECU that tunes down your car after adding mods very noticiably. You dont hear Mazda owners going and saying BS your car just sucks why do you even bother modding.....because it doesnt suck and you all figuired out how to fix it and i think thats awsome.

Cars have alot of weird crap that needs to be figuired out. I acutally appreciate your interest in our car it shows no matter what you might say we have piqued your interest so much that even though its such a useless topic to you its good to see your still interested enough to keep checking in.

So in a sence...you are saying that 350Z is like a closet-homosexual? but more like a closet-rx-8 lover?

Originally posted by rotarygod
Here's a good comparison of how a truly good sports car is the sum of its parts and rather than a single strength. After reading this then consider what proper ecu tuning will do for us.

http://www.edmunds.com/reviews/comparison/articles/101039/page002.html Great article and good points all around Rotarygod. But I gotta ask, who in the HELL from Edmunds performance tested the car? 0-60 in 6.6 seconds? No way. Even Consumer's Reports bested that time, and every one knows that they don't know how to drive performance cars. Sheesh.

Well, disconnecting the sensors is not the answer for sure. Our prototype "ABS fooler" module has a switch to select stock sensors or fake sensors. One part of the switch was open due to solder flux or oxide and that sure set a code in a hurry. Didn't even have to start the engine! Once we found that was the problem, it was too late to continue. Will try again tonight.

Kind of felt like "so many wires, so little time" ;)

Good luck on your project Friend. Hopefully it'll help those that are seeking the full potentional of off the line power.

Good Morning Fellas...

This was in the Tech forum, posted by a dude from the Mazda 6 board. Looks like they have the same fuel rich condition on the dyno.

snip from tech post on scanners ----------------------------------

The 4000 has been used on the Mazda6, but its just a scanner, you can't change parameters. It works pretty well, but there are small bugs. For instance, the program won't yet show the 2nd O2 sensor on bank2.

Maybe if you guys and us start pounding AutoXray with requests, we can get something done!

Here are a few threads regarding this:
http://mazda6club.com/forums/read.php?TID=12682
http://mazda6club.com/forums/read.php?TID=12084

BTW, we're having the same problem as you guys on the dyno. Car seems to be going into a safe mode and dumping boatloads of fuel at higher RPMs.

end of snip.......................................

Originally posted by RX-8 friend
Well, disconnecting the sensors is not the answer for sure. Our prototype "ABS fooler" module has a switch to select stock sensors or fake sensors. One part of the switch was open due to solder flux or oxide and that sure set a code in a hurry. Didn't even have to start the engine! Once we found that was the problem, it was too late to continue. Will try again tonight.

Kind of felt like "so many wires, so little time" ;)

Yeah - So I found out when I got to test my theory. Oh well - it was worth a try. I tried to find others reports on what they had done to work around it - but too many posts got in the way!

Would like to see some details how others have gotten on attempting this. Surely it is info we can all benefit from without having to be too much of a trade secret!

Cheers,
Hymee.

Canzoomer is serious about marketing a module for racing purposes, but I suppose he wouldn't shoot me if I told how we are doing so far.

The ABS is a Bosch unit. Those Germans are good! You can't fool the system with a resistor. The system can detect you are trying to fool it with a resistor only. Also when the vehicle is in motion the system looks for four AC signals of the same frequency plus or minus, not different for more than 3-4 sec. Soooo, we will be making a module that keeps the system happy, at somewhat higher expense than just resistors would have been.

At this time I see no way to make the installation of this easy (we had to cut four wires and tap four to pick off the signals we needed).

So I guess we or Mazda will not have to worry about "just anyone" doing this and killing themselves with no ABS on a whim.

Why does it work this way? Suppose you hit "something" that cut into the ABS sensor wire to one wheel. The system must fault if the cable is open, shorted, or even just resistive, even if the r value is the same as the sensor. It must sense this if moving or when you are starting the car (suppose overnight a squirrel knaws at the cable).

Very well done, Bosch!

the mazdaspeed protege has the sam eproblem of running way to rich.

Quick fix! Want to dyno your car? Before pulling on the dyno, remove the bolt holding the ABS sensor in each rear hub. Back the car on the dyno. Crawl under there and carefully pull the sensor out of the hub and secure it to a non-moving part with tape. Do your dyno runs, then crawl back under there and re-insert the sensors, pull off the dyno, and reinstall the bolts.

Better fix for racers later.

Quick!! Somebody dyno your car!! Or.... RX-8 friend, what baseline numbers resulted after confirming this technique was successful?

Based upon the threads I have read, people have stated the 1/4 mile times won't be affected as much, it's a common agreed upon fact that a burnout is necessary to obtain the most efficient 1/4 mile run, and if a 1/4 mile time was obtained by not burning out, it wouldn't have the benefits off the line.

In essence, none of the 1/4 mile times have been optimal in comparison with other vehicles....? Since I would assume most vehicles will do a burnout, then run the 1/4 mile. The RX-8 if burned out, goes into "limp mode", run is skewed. No burnout, doesn't have the benefits, run time is skewed....? Am I accurate in my interpretation of this(and related) threads?

Originally posted by Landon_Starr
Based upon the threads I have read, people have stated the 1/4 mile times won't be affected as much, it's a common agreed upon fact that a burnout is necessary to obtain the most efficient 1/4 mile run, and if a 1/4 mile time was obtained by not burning out, it wouldn't have the benefits off the line.

In essence, none of the 1/4 mile times have been optimal in comparison with other vehicles....? Since I would assume most vehicles will do a burnout, then run the 1/4 mile. The RX-8 if burned out, goes into "limp mode", run is skewed. No burnout, doesn't have the benefits, run time is skewed....? Am I accurate in my interpretation of this(and related) threads? That's MY read on it, which is why I am making such a big deal out of this.

Damned if you do, damned if you don't. Damn you MAZDA!!!

Originally posted by Landon_Starr
Based upon the threads I have read, people have stated the 1/4 mile times won't be affected as much, it's a common agreed upon fact that a burnout is necessary to obtain the most efficient 1/4 mile run, and if a 1/4 mile time was obtained by not burning out, it wouldn't have the benefits off the line.

In essence, none of the 1/4 mile times have been optimal in comparison with other vehicles....? Since I would assume most vehicles will do a burnout, then run the 1/4 mile. The RX-8 if burned out, goes into "limp mode", run is skewed. No burnout, doesn't have the benefits, run time is skewed....? Am I accurate in my interpretation of this(and related) threads?

How much of a burnout are we talking about here? Because doing an actual burnout on street tires (not slicks) is worthless and does not increase traction. The people that do burnouts on street tires do it just for fun.

Best launches have been achieved by reving the engine to between 7000 and 8000 RPMs, then dumping the clutch. This results in some serious wheelspin. I have no idea how much, as I haven't tried it yet, but it may be enough to trigger limp mode.

Only time I tried this I got MAD wheel hop and decided not to do it again until I learn some more :(

In my 20 timed runs I never got any "safe mode" lights on (ABS and the car with the wiggly lines symbol).

Some water burnouts, most not. Most runs up around 6k launch. Some wheelspin, but no axle tramp.

Cheers,
Hymee.

Good info, and interesting, since with my car as soon as the rears slip the car the "wiggly lines symbol" lights up. But the insidious thing is that I'm not sure any warning lights indicate when the car has gone into limp mode.

What I think I'll do the next time the roads get icy here is to find a nice slick patch and spin my rear tires on it for up to 20 seconds if need be, and see how long it takes to get a light. Maybe I'll GTech it before and after.

Canzoomer found that here in winter he had to start at 3-4k RPM. Anything higher would cause the limp mode as it had too much wheel spin. This was with the stage 1 mod., however. Without you might do better at a higher RPM.

I think you'll find it trip at 3-4 sec. of spin, but check to see. Be interesting if it's different from car to car. We found there are levels of "ECU worry". Some show no lights yet reduce power. Some show lights that go off if you just drive around the block. Some show lights that require battery disconnect for hours to remove.

The joys of testing computerized cars ;)

BTW, if you are dynoing the car you -DON'T- want to trip one of these conditions. It usually requires you to unstrap the car from the dyno and drive it around the block to reset. A very time consuming procedure!

Originally posted by RX-8 friend
Canzoomer found that here in winter he had to start at 3-4k RPM. Anything higher would cause the limp mode as it had too much wheel spin. This was with the stage 1 mod., however. Without you might do better at a higher RPM.

I think you'll find it trip at 3-4 sec. of spin, but check to see. Be interesting if it's different from car to car. We found there are levels of "ECU worry". Some show no lights yet reduce power. Some show lights that go off if you just drive around the block. Some show lights that require battery disconnect for hours to remove. Yeah, mine even lights up briefly when I do a hard shift from 1st to 2nd and break the tires loose.

Originally posted by RX-8 friend
Quick fix! Want to dyno your car? Before pulling on the dyno, remove the bolt holding the ABS sensor in each rear hub. Back the car on the dyno. Crawl under there and carefully pull the sensor out of the hub and secure it to a non-moving part with tape. Do your dyno runs, then crawl back under there and re-insert the sensors, pull off the dyno, and reinstall the bolts.

Better fix for racers later. Would you mind taking some pics of these sensors, so I know what to disconnect? Thanks...

Originally posted by Omicron
Good info, and interesting, since with my car as soon as the rears slip the car the "wiggly lines symbol" lights up. But the insidious thing is that I'm not sure any warning lights indicate when the car has gone into limp mode.


Have you got DSC turned OFF when this happens?

Originally posted by Omicron
Yeah, mine even lights up briefly when I do a hard shift from 1st to 2nd and break the tires loose.


I have only ever seen that when DSC is ON.

The situation I describe on the dyno happens when we already are "DSC OFF". It is impossibly to do anything on the dyno with it on.

These cars don't make enough power to warrant strapping them down. When we get to something like 240 or 250kW and above at the wheels is when they start to drive themselves up out of the rollers. I guess it really is a torque thing - as they tend to need to strap auto's down more than manuals.

It is great hearing different experiences for different folks! This forum is really great for that.

Cheers,
Hymee.

Originally posted by Hymee
Have you got DSC turned OFF when this happens? I have only ever seen that when DSC is ON.Come to think of it, I guess the DSC was on. LOL, I had forgotten.

These cars don't make enough power to warrant strapping them down. I disagree - I wouldn't risk my car on the dyno not strapped down... too much of a chance for something to go wrong and the car go crashing through the wall, perish the thought!

It is great hearing different experiences for different folks! This forum is really great for that.Agreed 100%. This is one of the things that makes this place so addictive!

Originally posted by Omicron
I disagree - I wouldn't risk my car on the dyno not strapped down... too much of a chance for something to go wrong and the car go crashing through the wall, perish the thought!


Fair enough. I guess I just let the experience of my tuner/dyno technician dictate what is necessary.

Cheers,
Hymee.

I have experienced wheelspin at 4000 RPM and thereafter noticed a reduction in power with the DCS turned off, It seems like the car is getting choked and the RPMs take longer to rev? somethings going on here! Why can't Mazda just install a high heat cat or let us do it, then they could put everything back to normal! it just dosen't make any sense why Mazda would build this type of car and just sit there and allow this to happen!

By using the old horsepower calculator:

http://www.douglevinmotorsports.com/HP_calc.htm

And entering the following:

15.18 et
93 mph
3050 pounds

This equals 192 wheel horsepower according to the trap speed
And also 173 wheel horsepower according to the ET. That seems about the average the RX-8 is making on the dynojet, between 170 and 190 wheel horsepower.

Thor.

Then there is that other old rule of thumb about wheel HP being about the same as engine kW.

177 rwHP ~ 177 fwkW

Would be interesting to compare to a G-Tech or a MrDyno measurement.

Cheers,
Hymee.

ABS Sensor ID
If you look at the hub with the wheel off you will see a wire going down to it from the inside fender. On the rear there are three bolts holding this assy., two for the cable and one for the sensor (right in the wheel hub). If you remove that bolt you can wiggle out the sensor. It's magnetic (variable reluctance device). Clean it off with a rag before reinserting it. They love to collect rusty iron filings.

I AGREE WITH RX8FRIEND
THE ONLY WAY TO SOLVE THIS PROBLEM IS TO FIND A WAY TO BYPASS OR FOOL THE COMPUTER MANAGMENT SYSTEM TO THINKING THAT WHENEVER WE PUT AN ADD ON THAT IT IS OK TO HAVE IT. ALL THIS WITHOUT EFFECTING THE DSC AND ABS CAUSE IF WE DON'T THAN THE CAR IS GOING TO KEEP GOING INTO LIMP MODE.
I WOULD SAY THE FOCUS ON IMPROVING THE 8 IS TO FIRST WORK OUT A MANAGEMENT SYSTEM THEN DO THE REST AS IT'S LIKE BYING ALL THE ACCESORIES FOR YOUR COMPUTER WITHOUT THE COMPUTER

WHY ARE YOU SHOUTING? ;)

BECAUSE IT MAKES US FEEL LIKE WE ARE BEING HEARD. :D

Oh, ok.

Hey Guy's, I didn't want to sound like I was complainig too much about the limp mode thing, because even with it happening, I still love my car! Good luck to those of you who will be doing the work to get around this tear in the achilles and thank you, because we will need it. Hey, Mazda, CAN YO HEAR US!

An idea about fooling a correct signal, why not connect the two rear sensor wires and connect them to only ONE of the sensors?

Of coarse the sensors must have a common ground though. If it's a symmetically driven sensor system then it's just not the way to go.

This may sound problematic at the sensors (long wire etc.) but should be a piece of cake at the ECU box.

Any thoughts?

Canzoomer and company are working on this, and reportedly have a fix theoretically worked out. But getting their Stage I mod out the door to all us anxious customers is priority #1 right now, so I suspect this won't get worked out until after the first of the year.

Dude,

Awsome times! Pitty about you trannies though :eek:

Best I could manage during a hot day was 15.0s @ 94MPH, 2.1s 60'

Cheers,
Hymee.

did you have mazda replace the tranny's and what did you tell them if this is so?

Judge, from what I have heard, the limp mode triggers even when you disable the DSC and TCS by holding the button down long enough to get the car-with-squiggly-lines dash light. Apparently the ECU "decides" that you must not have really meant to disable it if it gets lots of delta between the front and rear wheel turn rate.

There is no doubt that you have gotten AWESOME 60 foot and 1/4 mile times, but if the limp mode is indeed triggering, your times might be able to be even better if the car was prevented from going into limp mode. Canzoomer and company have repeatedly seen this mode happen on the dyno, and he thinks that it triggers when you get more than about 3 seconds of wheelspin, DSC/TCS disabled or not. So this begs the questions: When you launch, how long do your back wheels spin?

Omicron,

I think Judge Ito would know if the TCS interferred with his run. I have triggered it once with DSC/TCS disabled (5 sec press & hold).

I was fooling around and did a long burn out (~5 seconds) and when the ECU stepped in it felt like I hit a brick wall. The wheels instantly stopped spinning and the revs dropped to a more reasonable level.

It also put it into limp mode, which I was able to reset by shutting the car off then restarting it.

More good info, thanks. Sounds like the Judge is not spinning the wheels long enough to cause limp mode.

yeah, it sounds like Judge Ito has the proper tire Psi for max grip, maybe that's why he is not triggering limp mode, yet breaking transmissions! Hey Judge, not that I want to break my tranny, but what tire PSI do you use for those launches?

I his 60' time is 1.9, then he hasn't hit it yet (aka the 3 second theory). I've only ever seen it happen on the dyno. (ABS warning and TC warning lights, "DSC OFF" goes out). Lets call the "car-with-squiggly-lines" the Traction Control (TC) warning light from now on :)

Cheers,
Hymee.

Can you be in limp/safe mode without any indications in the dash? My understanding is that limp mode is indicated by either the ABS light or the CEL. I've never seen either of these on the road - and only the ABS light on the dyno. Does this mean I've never been in safe mode on the road?

Wildcard,

Canzoomer reckons that opn the engine dyno for long enough you eventually get a CEL. Perhaps his runs have been longer than ours - but you have seen how it works. Mark set an appropriate ramp rate for the gear we were in. The full test was probably about 10 to 20 seconds would you reckon? You have one on tape don't you?

Cheers,
Hymee.

Our dyno runs were done in 4th from a start speed of 75km/h with a ramp up to 195km/h. The ramps took 12 seconds. I checked on my camera.

On some of the runs, the ABS light was aleady on before the ramp. On the last run, it was off and Mark watched to see exactly when the ABS light came on. It came on at about 7000rpm, which was precisely the point on the curve where the mixture got richer and power reduced.

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.

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!

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.

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

Originally posted by THOR
By using the old horsepower calculator:

http://www.douglevinmotorsports.com/HP_calc.htm

And entering the following:

15.18 et
93 mph
3050 pounds

This equals 192 wheel horsepower according to the trap speed
And also 173 wheel horsepower according to the ET. That seems about the average the RX-8 is making on the dynojet, between 170 and 190 wheel horsepower.

Thor.

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

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

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 :eek: I wouldn't post it if it wasn't the truth :)

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?

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.

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

Originally posted by ranger4277
So.. how about posting up some of those dyno results? Pictures being worth a thousand words and all.

The final results I have posted at :
http://www.rx8club.com/showthread.php?s=&threadid=22633&perpage=15&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??

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.

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.

:SHOCKED: Thanks Tessa::dunno:

Check out this thread. http://www.rx8club.com/showthread.php?t=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.