Scott Posted May 12, 2014 Share Posted May 12, 2014 Would I be right in saying that the EGT temp from runner 6 shouldn't go above 950C? (1742F) What sort of temperature would be normal for idling? I'm currently seeing around 560C (1050F). Does that sound about right? Previously, when I had my temp sensor in the 1st decat, I was seeing around 550C maximum..... even on a blast (1020F). I'm not 100% certain where it would idle but I believe it was around 480C (900F). Car is idling just fine now, just want to be sure everything is safe before I fix everything in place Quote Link to comment Share on other sites More sharing options...
johnny g Posted May 12, 2014 Share Posted May 12, 2014 That sounds about right mate. When mine was idling (Big Twin manifold, with EGT in runner #6), I was seeing 450-500 on idle. I think EGT's should be 900-950 at the runner, but not more than that. I think I was about 880, again from memory. Quote Link to comment Share on other sites More sharing options...
Scott Posted May 12, 2014 Author Share Posted May 12, 2014 Sounds good, even there or there abouts I'm happy with.... I just don't want anything going BOOM. Ryan can get it all bob on when he's doing his thing Quote Link to comment Share on other sites More sharing options...
Steve Posted May 12, 2014 Share Posted May 12, 2014 As above, IIRC mine idles around 450. Sensor in runner 6. Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted May 12, 2014 Share Posted May 12, 2014 I wouldn't even worry about EGT at idle, all engines will differ slightly anyway, its on full load that you don't really want to see more than 950c. Quote Link to comment Share on other sites More sharing options...
Scott Posted May 12, 2014 Author Share Posted May 12, 2014 I wouldn't even worry about EGT at idle, all engines will differ slightly anyway, its on full load that you don't really want to see more than 950c. It was just for peace of mind more than anything. It was idling with a near 20:1 AFR so I was worried temps were going to go sky high. Ryan has tweaked it a little and it's now idling around the 15 mark which is more like it Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted May 12, 2014 Share Posted May 12, 2014 It was just for peace of mind more than anything. It was idling with a near 20:1 AFR so I was worried temps were going to go sky high. Ryan has tweaked it a little and it's now idling around the 15 mark which is more like it Understandable, however your reply gives rise to more questions, are you sure that AFR was 20.1? as free air is 20.9 so can an engine actually run with that AFR, are you sure that your wide-band was calibrated correctly? Quote Link to comment Share on other sites More sharing options...
Scott Posted May 12, 2014 Author Share Posted May 12, 2014 Understandable, however your reply gives rise to more questions, are you sure that AFR was 20.1? as free air is 20.9 so can an engine actually run with that AFR, are you sure that your wide-band was calibrated correctly? It wasn't on the money, but it wasn't far off it. It was probably closer to 19. It really struggled to keep idling, as soon as I touch the throttle it dies. Quote Link to comment Share on other sites More sharing options...
chrispot Posted May 13, 2014 Share Posted May 13, 2014 Understandable, however your reply gives rise to more questions, are you sure that AFR was 20.1? as free air is 20.9 so can an engine actually run with that AFR, are you sure that your wide-band was calibrated correctly? hi I don't mean to be picky but afr and the oxygen content in air are two seperate things, I think some lean burn cars can run a afr of 22:1. hope you understand. regards chris Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted May 13, 2014 Share Posted May 13, 2014 hi I don't mean to be picky but afr and the oxygen content in air are two seperate things, I think some lean burn cars can run a afr of 22:1. hope you understand. regards chris Well its an interesting point, however since an oxygen sensor measures the unburnt oxygen in the combustion process, and to recalibrate a wide-band sensor to free air results in an AFR of 20.9. for an engine to be running with an unburnt oxygen content of 22.1 it would need to be actually increasing the oxygen available in the combustion process, I have heard of lean burn engines running 17.1-18.00 but can you explain to me just how oxygen can be increased during combustion? Quote Link to comment Share on other sites More sharing options...
Andy Blyth Posted May 13, 2014 Share Posted May 13, 2014 Well its an interesting point, however since an oxygen sensor measures the unburnt oxygen in the combustion process, and to recalibrate a wide-band sensor to free air results in an AFR of 20.9. for an engine to be running with an unburnt oxygen content of 22.1 it would need to be actually increasing the oxygen available in the combustion process, I have heard of lean burn engines running 17.1-18.00 but can you explain to me just how oxygen can be increased during combustion? I think what Chris is trying to say is that when you mention 20.9, that is the percentage Oxygen content, by volume, of atmospheric air - not AFR. When you refer to an AFR of 22, that is the ratio of air (not Oxygen), by mass, to fuel. FWIW, I've found that the 2JZ will just about idle at an AFR of 22 (it's right on the limit - any leaner and it'll stall). In that condition, for every gram of fuel entering the engine, there will also be 22 grams of air entering. That air will have an oxygen content of around 20.9%. The air leaving the exhaust will have significantly less oxygen. Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted May 14, 2014 Share Posted May 14, 2014 How's the ecu doing Andy? I have not been subscribing to the Adaptronics site since a computer crash. Still happy with it? Are they still doing firmware updates? Quote Link to comment Share on other sites More sharing options...
chrispot Posted May 14, 2014 Share Posted May 14, 2014 Well its an interesting point, however since an oxygen sensor measures the unburnt oxygen in the combustion process, and to recalibrate a wide-band sensor to free air results in an AFR of 20.9. for an engine to be running with an unburnt oxygen content of 22.1 it would need to be actually increasing the oxygen available in the combustion process, I have heard of lean burn engines running 17.1-18.00 but can you explain to me just how oxygen can be increased during combustion? I know that a oxygen sensor measures air remaining after combustion, but they are no good when it comes very weak mixtures. as you said you recalibrate in free air, so how can the gauge show a air fuel ratio if there is no fuel present? I am not a expert on afr gauges. My gauge shows lean then displays AIR on a long enough run with the throttle off on over run, I am not saying that my gauge is any better than others that whould show a afr of 20.9 in that case. regards chris. Quote Link to comment Share on other sites More sharing options...
Tricky-Ricky Posted May 14, 2014 Share Posted May 14, 2014 I think what Chris is trying to say is that when you mention 20.9, that is the percentage Oxygen content, by volume, of atmospheric air - not AFR. When you refer to an AFR of 22, that is the ratio of air (not Oxygen), by mass, to fuel. FWIW, I've found that the 2JZ will just about idle at an AFR of 22 (it's right on the limit - any leaner and it'll stall). In that condition, for every gram of fuel entering the engine, there will also be 22 grams of air entering. That air will have an oxygen content of around 20.9%. The air leaving the exhaust will have significantly less oxygen. I know that a oxygen sensor measures air remaining after combustion, but they are no good when it comes very weak mixtures. as you said you recalibrate in free air, so how can the gauge show a air fuel ratio if there is no fuel present? I am not a expert on afr gauges. My gauge shows lean then displays AIR on a long enough run with the throttle off on over run, I am not saying that my gauge is any better than others that whould show a afr of 20.9 in that case. regards chris. You see that's my point, the wide-band sensor is used to achieve the desired lean fueling during closed loop in todays lean burn engines, AFAIK there are no new types of oxygen sensor available, unless anyone knows of any? And as you rightly say a wide-band AFR gauge will show 20.9 when the throttle is shut due to no fuel being injected or burnt, so in effect fee air oxygen, So if they are not accurate like you say then how is that achieved on a lean burn engine? and how can an engine idle at a genuine AFR of 22. if no fuel = 20.9? Quote Link to comment Share on other sites More sharing options...
chrispot Posted May 14, 2014 Share Posted May 14, 2014 You see that's my point, the wide-band sensor is used to achieve the desired lean fueling during closed loop in todays lean burn engines, AFAIK there are no new types of oxygen sensor available, unless anyone knows of any? And as you rightly say a wide-band AFR gauge will show 20.9 when the throttle is shut due to no fuel being injected or burnt, so in effect fee air oxygen, So if they are not accurate like you say then how is that achieved on a lean burn engine? and how can an engine idle at a genuine AFR of 22. if no fuel = 20.9? "And as you rightly say a wide-band AFR gauge will show 20.9 "as quoted by you. I have never said that, mine gauge shows air I said other gauges might show a afr of 20.9. surly you can see that if your sensor is in free air and gives a reading of 20.9 AFR thats wrong as there is no fuel?. no fuel no AFR. The gauge is set up to show AFR. there maybe some wideband sensors that can go to 23:1 as i said before I not a expert, or maybe that lean burn engines don't idle with a lean mixture and only lean off on light load/ cruise conditions, or use a combination of long and short term fuel trim to lean past the sensors range by a set percentage of the long term fuel trim when in light load conditions?, just guessing?. regards chris Quote Link to comment Share on other sites More sharing options...
Andy Blyth Posted May 15, 2014 Share Posted May 15, 2014 How's the ecu doing Andy? I have not been subscribing to the Adaptronics site since a computer crash. Still happy with it? Are they still doing firmware updates? Hello Chris; I'll send you an email. Quote Link to comment Share on other sites More sharing options...
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