merckx Posted March 16, 2007 Share Posted March 16, 2007 I've just fitted my AEM A/F gauge and I went out for a drive earlier. I'm BPU and I'm boosting to just over 1 bar. The AFR is dropping down to 10:1 which is a little scary considering that the AEM unit doesn't read any lower than this and the actual value could be possibly lower. I need some advice please? Quote Link to comment Share on other sites More sharing options...
wkdtime Posted March 16, 2007 Share Posted March 16, 2007 JDM Specs as far as i know can only adequately fuel to 1.0 Bar, after that they pretty much run the injectors on full duty. ********** Removed comments, thought you had an AEM EMS. Quote Link to comment Share on other sites More sharing options...
Homer Posted March 16, 2007 Share Posted March 16, 2007 What rpm is this at? Most I;ve seen at 1.0bar overfuel considerably at higher rpm, running to 1.2 helps lean things out to a better level. The lean spot to watch for is when the 2nd turbo is just starting to spool. JDM Specs as far as i know can only adequately fuel to 1.0 Bar, after that they pretty much run the injectors on full duty. If the injectors are in good condition they can fuel fine at 1.2bar, most are a little rich at the top end. Maybe you mean the MAP sensor can only read to 1.0 bar, which means the ECU can't adjust fuel once boost goes past 1.0. Typically it'll be at 100% duty at high rpm anyway. Quote Link to comment Share on other sites More sharing options...
Angarak Posted March 16, 2007 Share Posted March 16, 2007 How many miles have you done since you reconnected the battery after fitting the AEM AFR gauge? Could it be your ECU needs to relearn still? FWIW, my AFRs go down to 10:1 on full boost @ 1.2bar. Quote Link to comment Share on other sites More sharing options...
Pete Posted March 16, 2007 Share Posted March 16, 2007 Yes, it's quite normal. They run very rich at WOT. Quote Link to comment Share on other sites More sharing options...
Class One Posted March 16, 2007 Share Posted March 16, 2007 Better rich than lean. Det anyone? Quote Link to comment Share on other sites More sharing options...
wkdtime Posted March 16, 2007 Share Posted March 16, 2007 Maybe you mean the MAP sensor can only read to 1.0 bar, which means the ECU can't adjust fuel once boost goes past 1.0. Typically it'll be at 100% duty at high rpm anyway. Yup thats what i meant:) Quote Link to comment Share on other sites More sharing options...
merckx Posted March 16, 2007 Author Share Posted March 16, 2007 What rpm is this at? Most I;ve seen at 1.0bar overfuel considerably at higher rpm, running to 1.2 helps lean things out to a better level. The lean spot to watch for is when the 2nd turbo is just starting to spool. Not sure of the rpm , I was just looking for the AFR under full boost. I'll adjust the boost to take it upto 1.2bar and I'll see what I get. Thanks Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted March 17, 2007 Share Posted March 17, 2007 Yeah the AFRs go way rich at 1 - 1.2 bar but i have on cold days seen the duty cycle go to 95%, and in the summer i have seen AFRs of 9.5! i use an Innovate gauge, but in general i have a fair bit of fuel pulled from my EMU map. Quote Link to comment Share on other sites More sharing options...
Samurai 20V Posted May 22, 2012 Share Posted May 22, 2012 Bumping an old thread here.. I swapped out my AEM AFR for a HKS Knock Amp, it reads down to 8.0 AFR. On around 1.1bar at WOT above 4000rpm I was seeing AFR of 9.0.. SUrely this cannot be good for the motor, running that rich? This on my stock ECU, I am waiting for my Mines ECU to come back gonna compare the fuelling on the 2.. Is there anything I should be doing to improve the fuelling? Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted May 22, 2012 Share Posted May 22, 2012 Its basically a safety feature, the ECU fuel map is deliberately rich once a certain boost is reached, its the same on many older Japanese turbo cars, it done to help in cylinder cooling and suppress det, nothing you can do other then add a piggyback or different ECU. Quote Link to comment Share on other sites More sharing options...
Mugello Posted May 22, 2012 Share Posted May 22, 2012 Its basically a safety feature, the ECU fuel map is deliberately rich once a certain boost is reached, its the same on many older Japanese turbo cars, it done to help in cylinder cooling and suppress det, nothing you can do other then add a piggyback or different ECU. This Quote Link to comment Share on other sites More sharing options...
Samurai 20V Posted May 22, 2012 Share Posted May 22, 2012 Its basically a safety feature, the ECU fuel map is deliberately rich once a certain boost is reached, its the same on many older Japanese turbo cars, it done to help in cylinder cooling and suppress det, nothing you can do other then add a piggyback or different ECU. Thanks mate, I got worried seeing it so rich... In my understanding, with proper knock control, on boosted cars around 11AFR is optimum for max power? Does the the extra fuel have a major effect on the engine power? I am keen to check my Mines ECU fuelling once it returns to see if the map is similar on boost.. The power difference is noticeable between the two at 1.2bar so I reckon it should be somewhat leaner.. (depends on the timing as well I suppose).. Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted May 22, 2012 Share Posted May 22, 2012 I always aim for 11.2-11.4 AFR, but yes with it running in the 9s as opposed to 11 AFR there is bound to be a power loss, but yes ignition timing makes a huge difference too. Quote Link to comment Share on other sites More sharing options...
Samurai 20V Posted May 22, 2012 Share Posted May 22, 2012 I always aim for 11.2-11.4 AFR, but yes with it running in the 9s as opposed to 11 AFR there is bound to be a power loss, but yes ignition timing makes a huge difference too. Cool.. Lets see what the Mines is mapped to as a comparison.. Quote Link to comment Share on other sites More sharing options...
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