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Cobb Stage 1 Tune Unsafe?

Old Jan 19, 2010 | 01:04 AM
  #76  
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Originally Posted by TeamRX8
they may [B]have/B[] leaned it out some over the latest flashes, I'm remembering from a number of years ago

https://www.rx8club.com/showpost.php...77&postcount=6

note the there are some critical intake valve operations taking place between 6500 - 7500 rpm, the tuning may not seem normal in these areas depending on how smooth you want those power transitions to be
Fixed that for ya

So looking at the map the og poster posted, how do we know he did not alter the map?
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Old Jan 19, 2010 | 06:51 AM
  #77  
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Originally Posted by TeamRX8
they may ahve leaned it out some over the latest flashes, I'm remembering from a number of years ago

https://www.rx8club.com/showpost.php...77&postcount=6

note the there are some critical intake valve operations taking place between 6500 - 7500 rpm, the tuning may not seem normal in these areas depending on how smooth you want those power transitions to be
I got my 06 map just a few months ago, so that may not be exact reason.
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Old Jan 19, 2010 | 11:59 AM
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Originally Posted by thewird
Then tried some WOT pulls and observed the AFR. I saw 14's, 15's and even 16's at high RPM.
Typical for the Cobb ST1.
I have yet to see an OTS tune work on an RX-8.

Originally Posted by thewird
A rotary will not idle at 15 AFR smoothly if at all.
Not true.
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Old Jan 19, 2010 | 12:03 PM
  #79  
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Originally Posted by MazdaManiac
Typical for the Cobb ST1.
I have yet to see an OTS tune work on an RX-8.



Not true.
Read the other pages, mainly 3 >_>

thewird

Last edited by thewird; Jan 19, 2010 at 12:12 PM.
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Old Jan 19, 2010 | 12:18 PM
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Originally Posted by thewird
Read the other pages, mainly 3 >_>

thewird
There are only two pages.
If there is something you want me to see, link it.

The RX-8 must be custom tuned.
If you feel lucky, run the OTS map. Doesn't matter to me.

I've tuned HUNDREDS of these cars. OTS NEVER works.

EDIT - You are TURBO and you are running an OTS calibration? lol

Last edited by MazdaManiac; Jan 19, 2010 at 12:21 PM.
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Old Jan 19, 2010 | 12:50 PM
  #81  
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Originally Posted by MazdaManiac
There are only two pages.
If there is something you want me to see, link it.

The RX-8 must be custom tuned.
If you feel lucky, run the OTS map. Doesn't matter to me.

I've tuned HUNDREDS of these cars. OTS NEVER works.

EDIT - You are TURBO and you are running an OTS calibration? lol
Well, https://www.rx8club.com/showthread.p...34#post3391934 and everything after really. Basically there is something wrong with the 2004-2005 stage 1 maps and Cobb needs to fix it so people who don't know better don't damage their engines. I've already confirmed 2004-2005 need fixing, maybe you could help out with the other model years since you can open every map? I'd like to let Cobb know in one go instead of spurts of requests.

My car isn't turbo yet hehe, its still 100% bone stock. I just wanted to see what was different about the stage 1 map until I started making changes to the car. A stock car should be able to use the same map on every single car and work within a given range of the target. The only exception is if there is something wrong with a car like clogged injectors, fuel filters, bad fuel pump etc. but if that's the case, those things need to be taken care of instead of changing the map to compensate. Do you disagree?

thewird
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Old Jan 19, 2010 | 03:43 PM
  #82  
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Originally Posted by thewird
A stock car should be able to use the same map on every single car and work within a given range of the target. The only exception is if there is something wrong with a car like clogged injectors, fuel filters, bad fuel pump etc. but if that's the case, those things need to be taken care of instead of changing the map to compensate. Do you disagree?
I don't disagree - but you are talking about the stock Mazda calibration, which does work on every car.
There is no good way to make an OTS "tuned" calibration for the RX-8 because there is so much variation in the feedback and input.
That is why there is so much variation in the logging of a stock calibration and why Mazda made it so "safe".

Cobb's OTS can't be fixed because they are not broken. They work perfectly, but only on the car they were created for and none other.

I have well over 300 calibrations out there for NA RX-8s. Way more than anybody, including Cobb. They are all totally different, some radically different.
Even on mostly or completely stock RX-8s, the variation in MAF calibration and lambda targets from car to car is staggering.
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Old Jan 19, 2010 | 04:05 PM
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Quick question - What does OTS mean? I'm looking on google for the full phrase, but everyone uses it in the acronym form.
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Old Jan 19, 2010 | 04:08 PM
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OTS = Off The Shelf
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Old Jan 19, 2010 | 04:16 PM
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Hah! I was guessing that!

My only issue with the Cobb map is that they don't really have a universal map either. My map (when compared to the stock) is pretty much the same if not richer in certain areas. So that's not a bad map for me to run until I can buy the tunes from you, whereas wird's map is pretty lean to run for a long period of time assuming it is not customized for his car.
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Old Jan 19, 2010 | 04:33 PM
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Originally Posted by MazdaManiac
I don't disagree - but you are talking about the stock Mazda calibration, which does work on every car.
There is no good way to make an OTS "tuned" calibration for the RX-8 because there is so much variation in the feedback and input.
That is why there is so much variation in the logging of a stock calibration and why Mazda made it so "safe".

Cobb's OTS can't be fixed because they are not broken. They work perfectly, but only on the car they were created for and none other.

I have well over 300 calibrations out there for NA RX-8s. Way more than anybody, including Cobb. They are all totally different, some radically different.
Even on mostly or completely stock RX-8s, the variation in MAF calibration and lambda targets from car to car is staggering.
But why is the Stage 1 map calling for 14.7 AFR under full boost high RPM? I don't think that has anything to do with calibrations. Although I could be wrong!

thewird
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Old Jan 19, 2010 | 04:37 PM
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Originally Posted by thewird
But why is the Stage 1 map calling for 14.7 AFR under full boost high RPM? I don't think that has anything to do with calibrations. Although I could be wrong!

thewird
Because that probably yielded 13:1 or so on the car it was developed on with its MAF calibration.
What do you mean by "full boost"? I thought you just said you are N/A?

EDIT - I'm looking at the Cobb Stage 1 calibration right now and it "calls for" 12:1 - 13:1 at WOT and high RPM.
What you are actually getting is something else.

Last edited by MazdaManiac; Jan 19, 2010 at 04:39 PM.
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Old Jan 19, 2010 | 04:44 PM
  #88  
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I think he means full load.

I'm just a little confused now - Are you saying at Lambda = 1, the engine is calling for 14.7, but yielding 13:1 because of the MAF calibration?
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Old Jan 19, 2010 | 04:51 PM
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Originally Posted by MazdaManiac
Because that probably yielded 13:1 or so on the car it was developed on with its MAF calibration.
What do you mean by "full boost"? I thought you just said you are N/A?

EDIT - I'm looking at the Cobb Stage 1 calibration right now and it "calls for" 12:1 - 13:1 at WOT and high RPM.
What you are actually getting is something else.
Sorry, I ment WOT. Too used to dealing with turbo rotaries :P.

I took screenshots of a freshly downloaded Stage 1 2005 map. Someone else also posted a 2004 screenshot and it was the same. Have a look...

Stock


Stage 1 (2005 MT)


GTAW posted 2004 Stage 1 (MT)


thewird

Last edited by thewird; Jan 19, 2010 at 04:57 PM.
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Old Jan 19, 2010 | 05:19 PM
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Yeah? So?
My point is that is what they dialed in to get the desired AFR.
The lambda chart is nothing by itself.
It relies on the other load tables.

Its not a gloat, but that is what I get paid for.
Its not that its superficially difficult, but it requires a native understanding of the interactions.

Just the fact that I need to explain it at all shows the value of that understanding.

In any event, do what you will and believe what you want. Just realize that this is the reason you don't get detailed explanations from "experts" - it isn't worth the effort.

Last edited by MazdaManiac; Jan 19, 2010 at 05:23 PM.
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Old Jan 19, 2010 | 05:40 PM
  #91  
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Originally Posted by MazdaManiac
In any event, do what you will and believe what you want. Just realize that this is the reason you don't get detailed explanations from "experts" - it isn't worth the effort.
If it was easy, everyone would be doing it
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Old Jan 19, 2010 | 05:42 PM
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Originally Posted by JinDesu
I'm just a little confused now - Are you saying at Lambda = 1, the engine is calling for 14.7, but yielding 13:1 because of the MAF calibration?
There are various tables which work together to formulate the calculations that the PCM uses for fuel delivery. The target AFR is one of those tables.

Since the car doesn't utilize the o2 sensor for trimming fuel in open loop the fuel tables exist only as a modifier since there's no check to see if what you are getting is the actual air/fuel ratio your calling for.

As an example, I have areas of my fuel map that call for high 10's but produce 12's. This is why I laugh when I hear about people trying to "reverse engineer" AP maps because you cannot tell anything about how the tune interacts on the car what so ever.

This analysis of the Cobb stage 1 map is, in my opinion, beating a dead horse. The map is a general map and as Jeff stated all RX8's require custom maps. Just start with a stock map, take logs, make adjustments then rinse and repeat as necessary.
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Old Jan 19, 2010 | 05:49 PM
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Originally Posted by azzuro
If it was easy, everyone would be doing it
Well, there are a LOT of people that believe they can do it and when they have problems, they blame the people that tried to explain the process to them.
So, I don't really bother anymore.

I'm tired of having my hand bitten.
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Old Jan 19, 2010 | 06:08 PM
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^^wird

per my original post .....




.

Last edited by TeamRX8; Jan 19, 2010 at 06:12 PM.
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Old Jan 19, 2010 | 06:19 PM
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Originally Posted by MazdaManiac
Well, there are a LOT of people that believe they can do it and when they have problems, they blame the people that tried to explain the process to them.
So, I don't really bother anymore.

I'm tired of having my hand bitten.
nom nom nom nom
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Old Jan 19, 2010 | 09:56 PM
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Originally Posted by Flashwing
There are various tables which work together to formulate the calculations that the PCM uses for fuel delivery. The target AFR is one of those tables.

Since the car doesn't utilize the o2 sensor for trimming fuel in open loop the fuel tables exist only as a modifier since there's no check to see if what you are getting is the actual air/fuel ratio your calling for.

As an example, I have areas of my fuel map that call for high 10's but produce 12's. This is why I laugh when I hear about people trying to "reverse engineer" AP maps because you cannot tell anything about how the tune interacts on the car what so ever.

This analysis of the Cobb stage 1 map is, in my opinion, beating a dead horse. The map is a general map and as Jeff stated all RX8's require custom maps. Just start with a stock map, take logs, make adjustments then rinse and repeat as necessary.
Thanks Flash! I always considered myself too stupid to tune lol... this confirms that thought :D
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Old Jan 20, 2010 | 12:42 PM
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I honestly don't know how to respond to the above posts....

You know very well its screwed up, yet you don't care and blame it on working on the vehicle tested or "calibrations"? Have you even looked at the stage 1 map? The ONLY change in fuel is the table I have screenshoted. Every other table that effects fuel and the MAF calibration is 100% unchanged, a direct copy of the stock map. The only change is that fuel map, leading ignition (barely), and trailing ignition. No other changes are made to that map at all.

Leaving the benefit of the doubt, if what you say is true that the map worked on a specific car. Then that car must have had some fuel upgrades as the tendency for cars is to lose fuel capacity over time, not increase it. In which case it doesn't fall under the requirements of the map and should not be listed as such. The fact that you say the Stage 1 map doesn't work on any car, emphasizes this even more.

The above posts have left me really disappointed to a degree that I don't think you can understand...

thewird
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Old Jan 20, 2010 | 04:33 PM
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I don't know about you, but I don't really use Cobb stuff for the preloaded maps. I also know I didn't buy a Power FC for the base map!

Start with the stock fuel table and just lean it out a little at a time while checking AFR's. Some rpm ranges may be more prone to running lean due to the aux ports or VDI opening, be mindful of that. Your biggest problems on a stock Renesis are oil related... bad bearing lubrication (5W-20) and a bad OMP design. I wouldn't worry about detonation at all on an n/a setup, it takes a lot to cause that.

I know you're worried about the lean AFR's from the tune. But I'll go ahead and say that you could run that tune for a very long time and not notice any engine damage. It really takes a lot to damage an n/a.
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Old Jan 20, 2010 | 04:41 PM
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Neither did I but that doesn't mean the powerfc base map can't run every single stock fd out there that is in working condition even if it has an exhaust and an intake.

And yes I am worried about the lean afrs. I know an rx8 owner who runs in some endurance racing event and he tunes his own car. He was running high 13's and I suggested he not run so lean but he said the car ran better like that. Well a month later I saw him again with the motor out of his car. I asked what happened and he said the motor lost power. When I asked the builder what he thought happened, he said he was running too lean. The engine parts which were on the table had been destroyed and he needed to start with a new engine. I also noticed the exhaust ports were white. It may work fine for a bit but the exhaust heat from running that lean will eventually take its toll.

thewird

Last edited by thewird; Jan 20, 2010 at 05:23 PM.
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Old Jan 20, 2010 | 04:53 PM
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I love a good train wreck ....
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