Cobb Stage 1 Tune Unsafe?
#26
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Thread Starter
Sigh, looks like I have to do the air pump test before getting anywhere on the actual issue of the stage 1 map.... I needed to move the car anyway to change my spark plugs...
thewird
thewird
#28
Do your own tune, sounds like you have quite a bit of rotary experience.
#29
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Thread Starter
Sorry, I can't stand misinformation. If I'm wrong I'd like to get that sorted as well.
I plan too but I'm worried about the stage 1 map. I'm sure a lot of owners out there run on the stage 1. And if there is nothing wrong with the map, then I can only conclude there is something wrong with my car. Either way I'd like to find out.
thewird
thewird
#31
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Airpump is only on for a very short period of time after startup.....it's electric..not like the old RX-7's that had a belt driven pump that was on all the time
The Renesis idles at close to stoich due to the altered ignition timing that the stock ECU uses at idle..it fire the trailing plug first.....
#32
Hooked on go-fast crack
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Thewird, I saw similar things when I tried the stage 1, so I stopped using it. I saw others on the forum mentioning the same thing, so I don't think it is anything wrong with your car.
Sidenote - 146 kph... With certain laws in effect in Ontario, an awful lot of my logs peak at just about the same place!
Sidenote - 146 kph... With certain laws in effect in Ontario, an awful lot of my logs peak at just about the same place!
#33
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Thread Starter
Airpump is only on for a very short period of time after startup.....it's electric..not like the old RX-7's that had a belt driven pump that was on all the time
The Renesis idles at close to stoich due to the altered ignition timing that the stock ECU uses at idle..it fire the trailing plug first.....
The Renesis idles at close to stoich due to the altered ignition timing that the stock ECU uses at idle..it fire the trailing plug first.....
Thewird, I saw similar things when I tried the stage 1, so I stopped using it. I saw others on the forum mentioning the same thing, so I don't think it is anything wrong with your car.
Sidenote - 146 kph... With certain laws in effect in Ontario, an awful lot of my logs peak at just about the same place!
Sidenote - 146 kph... With certain laws in effect in Ontario, an awful lot of my logs peak at just about the same place!
As for the speed, meh. I've done worse, pegged my speedo in the RX-7 before testing the shorter JDM 5th gear (290+ km/h).
thewird
#35
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Thread Starter
Obviously open loop during a WOT pull. Maybe its model year specific since there are different maps for different years. Mine is a 2005.
Well, it was a semi-warm day yesterday so I changed my spark plugs. But look what I found on the rear trailing side... I thought this might be a possible reason for the leanness since if its not burning the fuel, it will register lean. But loading the stage 1 map again and driving for about an hour, trying to do a pull again and it did the exact same thing, 14-16 AFR. I left the stage 1 map on there just to see if it changes over a longer period of time but I doubt it.
![](https://www.rx8club.com/attachments/series-i-engine-tuning-forum-63/150488d1263730340-cobb-stage-1-tune-unsafe-img00008-20100117-0706-small-.jpg)
thewird
Well, it was a semi-warm day yesterday so I changed my spark plugs. But look what I found on the rear trailing side... I thought this might be a possible reason for the leanness since if its not burning the fuel, it will register lean. But loading the stage 1 map again and driving for about an hour, trying to do a pull again and it did the exact same thing, 14-16 AFR. I left the stage 1 map on there just to see if it changes over a longer period of time but I doubt it.
![](https://www.rx8club.com/attachments/series-i-engine-tuning-forum-63/150488d1263730340-cobb-stage-1-tune-unsafe-img00008-20100117-0706-small-.jpg)
thewird
#37
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thewird
Last edited by thewird; 01-17-2010 at 10:07 AM.
#38
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Do you mean think like how the air pump really works before you argue with people?
Or do you mean think like the leading plug should still be firing and putting out incomplete combustion in open loop (AFR = Air/Fuel Ratio)
Or perhaps you mean think like what was the AFR reading before the change and is the engine in proper operating condition; no defects in the ignition, fuel, and air systems?
![Dunno](https://www.rx8club.com/images/smilies/dunno.gif)
.
Or do you mean think like the leading plug should still be firing and putting out incomplete combustion in open loop (AFR = Air/Fuel Ratio)
Or perhaps you mean think like what was the AFR reading before the change and is the engine in proper operating condition; no defects in the ignition, fuel, and air systems?
![Dunno](https://www.rx8club.com/images/smilies/dunno.gif)
.
#39
Registered
Thread Starter
Do you mean think like how the air pump really works before you argue with people?
Or do you mean think like the leading plug should still be firing and putting out incomplete combustion in open loop (AFR = Air/Fuel Ratio)
Or perhaps you mean think like what was the AFR reading before the change and is the engine in proper operating condition; no defects in the ignition, fuel, and air systems?
![Dunno](https://www.rx8club.com/images/smilies/dunno.gif)
.
Or do you mean think like the leading plug should still be firing and putting out incomplete combustion in open loop (AFR = Air/Fuel Ratio)
Or perhaps you mean think like what was the AFR reading before the change and is the engine in proper operating condition; no defects in the ignition, fuel, and air systems?
![Dunno](https://www.rx8club.com/images/smilies/dunno.gif)
.
thewird
Last edited by thewird; 01-17-2010 at 12:15 PM.
#41
The Rx-8's can idle leaner than a peripheral exhaust port engine because of the lack of overlap and also a different firing order used on the Rx-8 PCM. The leading is NOT waste sparked on a Renesis, and negative split is utilized. The ignition system is actually much better on the Rx-8's despite the very weak coil design.
Can you email me the Rx-8 stock and stage one maps? I have Accessmanager and Accesstuner race for Subaru, I think I might be able to pull them up.
Can you email me the Rx-8 stock and stage one maps? I have Accessmanager and Accesstuner race for Subaru, I think I might be able to pull them up.
#42
Modulated Moderator
iTrader: (3)
When you have a missfire, or improper ignition...your AFR is anyones guess.....depending on the location of the sensor it can read rich, lean..or all over the map...
You need to fix the underlying problems before you can tune....simple as that...I think that was what Team was trying to say in his ever gentle way![Wink](https://www.rx8club.com/images/smilies/wink.gif)
You need to try and look at the RX-8 as a much different system than the RX-7's. The PCM is much smarter..and much more intrusive
You need to fix the underlying problems before you can tune....simple as that...I think that was what Team was trying to say in his ever gentle way
![Wink](https://www.rx8club.com/images/smilies/wink.gif)
You need to try and look at the RX-8 as a much different system than the RX-7's. The PCM is much smarter..and much more intrusive
#43
The Rx-8 PCM is just like the Evo's and the STi's. They're all Denso based and they all use a similar processor. Of course there is different hardware attached but's the same basic thing.
#45
This is from a Toyota emissions diagnosis training course:
![](https://www.rx8club.com/attachments/series-i-engine-tuning-forum-63/150511d1263759521-cobb-stage-1-tune-unsafe-misfire1.jpg)
![](https://www.rx8club.com/attachments/series-i-engine-tuning-forum-63/150512d1263759521-cobb-stage-1-tune-unsafe-misfire2.jpg)
Please, don't make an emissions diagnosis without the proper training or equipment.
#48
Registered
Thread Starter
I already admitted to being mistaken about the air pump after testing it myself. I pulled the fuse, it read the same, I didn't believe it so I disconnected the air pump manually, and it read the same. I was never arguing with anyone? I had assumed it worked similar to the 3rd gen where its on until 3,000 RPM and when I tune them, I pull the connector until I get the drivability tuned.
Aside from arghx7's explanation, in my own experience tuning a 3rd gen I once tuned a car who had bad coils and would randomly go leaner at higher boost when I knew the fuel map was perfectly fine. After checking fuel pressure which was fine, noticed how the dyno graph wasn't as smooth as other cars are. We changed the coils and voila, car went richer.
The Rx-8's can idle leaner than a peripheral exhaust port engine because of the lack of overlap and also a different firing order used on the Rx-8 PCM. The leading is NOT waste sparked on a Renesis, and negative split is utilized. The ignition system is actually much better on the Rx-8's despite the very weak coil design.
Can you email me the Rx-8 stock and stage one maps? I have Accessmanager and Accesstuner race for Subaru, I think I might be able to pull them up.
Can you email me the Rx-8 stock and stage one maps? I have Accessmanager and Accesstuner race for Subaru, I think I might be able to pull them up.
I don't think you'll be able to open them but I'll send them to you when I get home nevertheless.
Also, the rear trailing plug was firing since it was not fouled. I only loaded the stage 1 map on because there was always a possibility that at higher RPM or higher speeds, the vibration could loosen it and make it lose contact (the metal piece was still in there, just broken). So I took it for a drive to see if anything changed and it didn't.
I never blamed Cobb. As you see from the thread title it was possed as a question and not an accusation. What I find odd is that the stock map works fine but the Stage 1 does not. From my understanding, there not supposed to be much different.
thewird
#49
Read this SAE paper on the Renesis: http://www.rotarydevelopment.net/Rot...790_Rotary.pdf
it explains that the air pump is not used AT ALL during normal driving on a Renesis. That is because using side exhaust ports gave Mazda the flexibility to eliminate the overlap between intake and exhaust as I'm sure you're aware. Without the overlap there was a 30% reduction in the internal EGR effect which that diluting the intake charge on the REW. That internal EGR effect was the reason why the REW required such a rich mixture and then an airpump on top of that to keep emissions down. There's also a redesigned injector air bleed/atomization port design... it's a lot of cool stuff in there, especially to people who are so familiar with the old designs.
The Renesis is so much better than the REW in so many areas. The only thing the REW has over the Renesis is the simple fact that it was designed to be turbo from the start. And that makes a huge difference in the end to the normal enthusiast.
Also, please email me what I requested in the PM.
it explains that the air pump is not used AT ALL during normal driving on a Renesis. That is because using side exhaust ports gave Mazda the flexibility to eliminate the overlap between intake and exhaust as I'm sure you're aware. Without the overlap there was a 30% reduction in the internal EGR effect which that diluting the intake charge on the REW. That internal EGR effect was the reason why the REW required such a rich mixture and then an airpump on top of that to keep emissions down. There's also a redesigned injector air bleed/atomization port design... it's a lot of cool stuff in there, especially to people who are so familiar with the old designs.
The Renesis is so much better than the REW in so many areas. The only thing the REW has over the Renesis is the simple fact that it was designed to be turbo from the start. And that makes a huge difference in the end to the normal enthusiast.
Also, please email me what I requested in the PM.
#50
rot8ing
iTrader: (1)
it's barely different from stock. seriously, there is no reason it should cause such lean conditions in a car that is functioning properly.
Last edited by myriadshalaks; 01-17-2010 at 09:14 PM.