02 feedback & HKS F-Con

[suprafan72]

Ok here are my thoughts on this subject.

 

The standard supra ECU uses an "o2 feedback system/Closed loop O2" for when the car is cruising and idling the keep the AFR around stoich for Emission tests purposes and good MPG.

 

Now i use this feature on some ecu's too for Mimicking the standard closed loop system but I set it so it is used up to 0 Psi and 4000 rpm which is roughly the same as the Toyota setup. I would never though dream of using it after these parameters unless the rich and lean limit were set at around 2-3% even still I would not be happy with leaving it on.

 

Now let me explain why

 

The ecu will be looking at a analog input from a wideband O2 sensor for it to see AFR on boost and it will be reporting back to the ecu in a format of 0-5v. Now for those who don’t know 0v = rich (7.35:1 AFR for most widebands) and 5v = lean (22.39:1 AFR).

 

Now if a sensor or a wideband controller fails or say the fuse goes that analog output from the wideband controller will supply 0 voltage which as I just just explains means it will be telling the ecu its seeing a AFR which is Very rich. The Ecu Will then adjust the fueling of the engine to try and get it back to the target AFR which means it will be pulling fuel depending on what the lean or rich limit is set at. In most AEM maps I have seen this is normally set at between 10% and 25%.

 

Pulling even 10% at say 1bar is going to cause the engine to be extremely unhappy let along 25% of the fuel map.

 

But if people did decided they wanted to set this I would have thought they would have turned the knock control on at least

 

I dont have a problem with Mike B setup as it has a very good knock control system linked to it aswell if this problem did occur and doubt it has the ability to pull up to 10% of fuel.

 

I want people to know that I am not trying to gain any more mapping for myself by slating this setup as I don’t even offer mapping of AEM’s unless it’s for a friend of a friend. I am just shocked that it is being done like this and that the person who does this has already ruined 2 engines of VERY good friends of mine which i am not happy about

 

Great Right up Ryan ....... Im sure the AEM is a good unit in the right hands but in the wrong hands (like any ecu) It can be lethal..

 

I'd be interested to know Mr Turner Justify's his mapping techniques on Supra.. and why he thinks his methods are best..

 

Allso i'd like him to explain why he thinks stock engines are happy to run 950 and 1000 egt's without any issues..

 

As Chris Wilson rightly says running a 1000 deg egt is race engine territory not stock road car one..

 

I am sorry if I appear to be very angry but the fact is I am and I don't suffer fools gladly...

 

It's for everyone to make there own mind up.. I am merely expressing my oponion on the subject.

[Tricky-Ricky]

"The ecu will be looking at a analog input from a wideband O2 sensor for it to see AFR on boost and it will be reporting back to the ecu in a format of 0-5v. Now for those who don’t know 0v = rich (7.35:1 AFR for most widebands) and 5v = lean (22.39:1 AFR)."

 

Thats interesting and a little worrying Ryan,

I always thought that the std ECU look for a 0-1v signal and stoic was 0.45V which is the switch point for narrow band signal? can you elaborate a little more?

[JustGav]

"The ecu will be looking at a analog input from a wideband O2 sensor for it to see AFR on boost and it will be reporting back to the ecu in a format of 0-5v. Now for those who don’t know 0v = rich (7.35:1 AFR for most widebands) and 5v = lean (22.39:1 AFR)."

 

Thats interesting and a little worrying Ryan,

I always thought that the std ECU look for a 0-1v signal and stoic was 0.45V which is the switch point for narrow band signal? can you elaborate a little more?

 

Sneaky feeling, he means on the aftermarket ECU's and not on the stock ECU's. Narrow bands indeed give you that VERY restricted view of the AFRs.

[Mike B]

Now if a sensor or a wideband controller fails or say the fuse goes that analog output from the wideband controller will supply 0 voltage which as I just just explains means it will be telling the ecu its seeing a AFR which is Very rich. The Ecu Will then adjust the fueling of the engine to try and get it back to the target AFR which means it will be pulling fuel depending on what the lean or rich limit is set at. In most AEM maps I have seen this is normally set at between 10% and 25%.

 

I know exactly what you mean, and if it were not for the knock control system on mine I would want to know more.. for it "remapped' itself for the gt4088R with alarming speed. There must be some kind of failsafe in the Vpro for this eventuality, and if it were not for the etcs on the vvti I would have been writing mails to them 12 months ago!!

 

Infact i shall put a post on sumo's thread and see if he cares to comment.. it would be interesting to know.

 

O2 sensors aside, there is a lot of other stuff that can conspire to blow your engine up too.... even a knock sensor to a big red light on the dash would be must for me on any single. If not a pair of det cans wired into your stereo!

[Mike B]

Ah... just realised..

 

now I am going to take a stab at this...

 

I know that the target afr feature can ONLY be used with the knock/afr sensor that is a bolt on addition to the ecu. So my guess is that the feature can only be used when it's also set up to detect knock, and if it does it will do something about it.. not pull up a chair and watch it go bang. It has a knock level readout on the AFR screen, and you can setup warning limits etc...

 

I PM'd Andy Barns to comment, and defend the honour of the mighty Vpro.. lol.

 

Come on Ryan, get on that Vpro course... you know you want to.. think of all those muti-millionaire skyline owners!

[Ryan.G]

The good thing with your setup and while it would not worry me Mike is the FBW being setup properly so in the chance that the sensor did fail, the knock sensor would pickup the noise and close the throttle. Like it did on your dyno run

 

With regard to vpro software, I dont feel the need of work mike to apply for the dongle and the software but might have access to it soon of a good friend

[Sumo Power]

Hi Mike,

 

Thanks for your PM and the link to this thread

 

Sadly to dissapoint, I cant answer the question as I am not a mapper or engine builder ( although I have an opinion on it which I wont share as I am not qualified to give such false hope ), HKS or Do-Luck do that for us and I honestly dont care how it does what it does, its a tool for the job and you get someone competant to use it, just like the engines, I dont want to claim we made an engine and that makes us 'great', I care only for the result and that it works fine whilst in our car.

 

I would like to share that practise with those here reading this and the other woes of engine building and mapping in the hope that someone may listen and take heed when searching for a magic deal / person that no-one else has discovered yet - it doesnt exist

 

BTW, FUUJIN runs 700 degs EGT max ( data logged ), measured at the turbo exhaust flange, doesnt emit black smoke, doesnt emit blue smoke and doesnt blow up - no matter how hard I keep trying

 

Andy

 

Ps. I realise HKS nor Do-Luck can map your car for you however some HKS mappers have V Pro capabilities for a reason, not every tuner is able to get V Pro and there is a reason for that along with the reason you cant buy and map a V Pro yourself as you can other ecu's.