Tricky-Ricky Posted April 5, 2010 Share Posted April 5, 2010 EGTs are influenced a lot by cam timing and overlap as well;) Quote Link to comment Share on other sites More sharing options...
MartinBattye Posted April 6, 2010 Share Posted April 6, 2010 I just googled "EGT's on cruise" and it took me to this thread, my egts seem pretty high to me, on cruise at say 90mph they read a constant 800c, peak at about 860c at 100mph off boost, soon as i touch the throttle they do go down a bit. At them temps should the manifold not be glowing? maybe dodgy sensor? its always been like this from when i first went single. A full wot through the gears run i see about the same egts, 850-870c at 2bar. what are others seeing at 90mph on cruise? light load ign timing problem Quote Link to comment Share on other sites More sharing options...
JamieP Posted April 8, 2010 Share Posted April 8, 2010 light load ign timing problem No, turned out to be down to a plug change, put another set of the original plugs in and my egts on cruise went down immediately. Quote Link to comment Share on other sites More sharing options...
dandan Posted April 8, 2010 Share Posted April 8, 2010 No, turned out to be down to a plug change, put another set of the original plugs in and my egts on cruise went down immediately. What did you change to J? And was it the NGK's you went back to? Quote Link to comment Share on other sites More sharing options...
nigelboyne Posted April 8, 2010 Share Posted April 8, 2010 learning bout this afr mine looks to be 11-5-1 at full boost when it was mapped. i persume this is safe Quote Link to comment Share on other sites More sharing options...
johnny g Posted April 8, 2010 Share Posted April 8, 2010 That's fine mate - mines the same, I think 11.8 is the highest, and 11.2 the lowest, staying around 11.6 mainly. Quote Link to comment Share on other sites More sharing options...
MartinBattye Posted April 8, 2010 Share Posted April 8, 2010 No, turned out to be down to a plug change, put another set of the original plugs in and my egts on cruise went down immediately. which where the "other" plug? surely you noticed a misfire also? Quote Link to comment Share on other sites More sharing options...
JamieP Posted April 8, 2010 Share Posted April 8, 2010 Who said anything about a misfire? no misfire was present. Quote Link to comment Share on other sites More sharing options...
MartinBattye Posted April 8, 2010 Share Posted April 8, 2010 learning bout this afr mine looks to be 11-5-1 at full boost when it was mapped. i persume this is safe afr required depends greatly on fuel type , IAT and a host of other things that dont concern this thread(all the same engine) Quote Link to comment Share on other sites More sharing options...
MartinBattye Posted April 8, 2010 Share Posted April 8, 2010 Who said anything about a misfire? no misfire was present. for there to have been a significant increase in egt there must have been a combustion problem?? other than that the plug itself wouldnt influence egt?. so where the plugs of vastly different heatrange? Quote Link to comment Share on other sites More sharing options...
Scott Posted April 8, 2010 Author Share Posted April 8, 2010 afr required depends greatly on fuel type , IAT and a host of other things that dont concern this thread(all the same engine) Why don't they concern this thread? My original question... that I started this thread with... was asking about safe AFR's. It's in the heading Quote Link to comment Share on other sites More sharing options...
JamieP Posted April 8, 2010 Share Posted April 8, 2010 for there to have been a significant increase in egt there must have been a combustion problem?? other than that the plug itself wouldnt influence egt?. so where the plugs of vastly different heatrange? As the problem is now fixed i have no need to discuss it anymore. Quote Link to comment Share on other sites More sharing options...
MartinBattye Posted April 8, 2010 Share Posted April 8, 2010 Why don't they concern this thread? My original question... that I started this thread with... was asking about safe AFR's. It's in the heading the other variables arent in the equation since you guys are quoting af figures from identical engines...(less small changes, but the general layout is the same) so dependant on where you are with ambient temps and fuel type changes your required AFR. it is generally considered that a figure 12or lower is a "safe" AF.. but this could change with poor fuel, high inlet temp, etc. for eg.. the ford yb engine will not tolerate an AF of 12 at high boost.. it will tend to knock.. but an evo engine will.. these are the engine design variables that i was on about.. im babbling now. Quote Link to comment Share on other sites More sharing options...
Scott Posted April 8, 2010 Author Share Posted April 8, 2010 Ahhh, with you now. Quote Link to comment Share on other sites More sharing options...
MartinBattye Posted April 8, 2010 Share Posted April 8, 2010 As the problem is now fixed i have no need to discuss it anymore. erm.. ok.. Quote Link to comment Share on other sites More sharing options...
ManwithSupra Posted July 23, 2011 Share Posted July 23, 2011 My AFR at WOT is around 10.5 is that ok? Idle is between 14.7 and 15.2 Sorry for thread resurrection Quote Link to comment Share on other sites More sharing options...
johnny g Posted July 23, 2011 Share Posted July 23, 2011 My AFR at WOT is around 10.5 is that ok?Idle is between 14.7 and 15.2Sorry for thread resurrectionWOT is a bit rich, but not bad. Quote Link to comment Share on other sites More sharing options...
ManwithSupra Posted July 23, 2011 Share Posted July 23, 2011 WOT is a bit rich, but not bad. Cheers mate Quote Link to comment Share on other sites More sharing options...
mellonman Posted July 23, 2011 Share Posted July 23, 2011 mine always goes mega rich 10.0 at 3200 rpm then goes to 11.2 once second turbo is running wot. richer is safe though right? what happens if you are too rich? Quote Link to comment Share on other sites More sharing options...
ManwithSupra Posted July 23, 2011 Share Posted July 23, 2011 mine always goes mega rich 10.0 at 3200 rpm then goes to 11.2 once second turbo is running wot. richer is safe though right? what happens if you are too rich? Running Rich is ok but then too rich you lose power, its lean you have to worry about. Quote Link to comment Share on other sites More sharing options...
dr_jekyll Posted July 23, 2011 Share Posted July 23, 2011 too rich is also bad. bore wash can cause big damage Quote Link to comment Share on other sites More sharing options...
CanisLupus Posted July 23, 2011 Share Posted July 23, 2011 @EGTs AFAIK 950°C is the maximum you'll want to see over a longer period and up to 1000°C short term. That's if the probe is in one of the runners of course. The Problem with EGT Probes after the turbo is that no one really knows a number how much you have to add because with different Sizes of turbos and housings the heat transported changes. So one turbo could lower the temps 100°C while another will 150°C and a third maybe just 50°C Other thing ist that the Temperature rise and fall is much slower than when in the runner. So while your Probe still shows a "safe" value after the Turbo the real EGT before can be over the max already. Quote Link to comment Share on other sites More sharing options...
mellonman Posted July 25, 2011 Share Posted July 25, 2011 (edited) so at what boost do you come away from stoich (14.7) afr ? or should i say when does the stock ecu take it away from stoich Edited July 25, 2011 by mellonman (see edit history) Quote Link to comment Share on other sites More sharing options...
Ian C Posted July 25, 2011 Share Posted July 25, 2011 There is an assortment of strategies. One is "Am I over 4000rpm?", another is "how much boost am I running?", and a third is "How fast has the throttle just changed position?". All of those can knock it out of closed loop. The exact values, though, remain a mystery Quote Link to comment Share on other sites More sharing options...
mellonman Posted July 26, 2011 Share Posted July 26, 2011 (edited) The thing is i have hybrids and i have a fic and see boost say 0.5 bar and run into afrs of 13s on part throttle at say 2500 rpm if i stay at that boost or a little more slowly accelateing the stock ecu still wants to go back to 14.7 but by then i have seen boost of 0.6. at 3000 then when in open loop go rich 10.0 i think off the scale i was thinking this was lean for that sort of boost even for part throttle? or does the stock ecu take into account intake temps and tps and other things i was worried that the fuel cut % was making it see the way less boost then what it was getting Edited July 26, 2011 by mellonman (see edit history) Quote Link to comment Share on other sites More sharing options...
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