Adam W Posted December 23, 2002 Share Posted December 23, 2002 Is it possible to tune a cars fuel mixture by reading the EGT gauge? Mine reads 780C pre-turbo, which suggests to me that I could lean out my mixture and run some more boost without any problems. I know that a possible problem is that the EGT gauge takes a while to react to changes in fuel mixture, but those reading were obtained after a full throttle, high revs pull from 3000rpm in third all the way up to 130-140mph. I did it a few times and the readings were very consistent. Quote Link to comment Share on other sites More sharing options...
Suprash Posted December 23, 2002 Share Posted December 23, 2002 When Im sat on a motorway doing 100mph, my EGT is reading 700C, how does that compare to you..... And at what temp do things start to melt, I think I read it was around 850C+. Quote Link to comment Share on other sites More sharing options...
Matt Harwood Posted December 23, 2002 Share Posted December 23, 2002 I'm certainly not the most technical bod on here but I can tell you that if I push the boost up to far, (anything over 1.3), my gauge can climb into the 900+'s within a couple of seconds or less easily. IIRC 925 is about the max before things start melting. Mine's been up to 1000 but only for a second or so. And I'm fairly convinced I can hear det at 950+ Seek more knowledgeable advice first, then wind it up Sounds to me like you have more room for higher boost Quote Link to comment Share on other sites More sharing options...
Terminator Posted December 23, 2002 Share Posted December 23, 2002 I have my warning set to 900. However I have only seen the other side of 800 once. Mid to high 700's seem to be the norm for boost around the 1.1 to 1.2 bar range for me at the moment in air temps of around 5 -10 degrees and a stock IC in good condition AFAIK the odd peak at 900 to 950 is not immediately threatening but running over that temp for sustained bursts will lead to problems. It will take a little while for the gas temperatures to be transferred to the internals, but there will be local hot spots that will heat up very quickly and cause det. Quote Link to comment Share on other sites More sharing options...
GavinL Posted December 23, 2002 Share Posted December 23, 2002 Originally posted by Adam Wootten Is it possible to tune a cars fuel mixture by reading the EGT gauge? No, EGT readings are too slow. Quote Link to comment Share on other sites More sharing options...
Neil Sandham Posted December 23, 2002 Share Posted December 23, 2002 And at what temp do things start to melt, I think I read it was around 850C+. [/b] I understand that the odd burst over 900 is fine and will not cause any damage. sustained I would probably think 850-875 was safe. Chris W is yer man I guess. cheers Neil. Quote Link to comment Share on other sites More sharing options...
Nathan Posted December 23, 2002 Share Posted December 23, 2002 Originally posted by Neil Sandham I understand that the odd burst over 900 is fine and will not cause any damage. sustained I would probably think 850-875 was safe. We've had these engines up to 1125 deg C, pulled them apart and found no damage. Wouldn't reccomend it though. 950 deg C is my personal max limit. Don't forget that you need a lot of load to get a decent EGT reading. It's no good going for a quick blast up to say 100mph (unless thats as hard as your drivng ever gets). To get a meaningful figure you need to really load the car up, say 160mph, and keep it thereabouts for at least 20 secs, with as much boost as you have the bottle for. Sustained full boost and load is what you need. It's not unusual for 1.2bar with exhaust & frontpipe on stock IC/turbos to reach 850~900 deg C. Cheers, Nathan TDI PLC Quote Link to comment Share on other sites More sharing options...
SMW Posted December 23, 2002 Share Posted December 23, 2002 Is there a rough percentage figure by which these temperatures are reduced if you have installed a fmic? Quote Link to comment Share on other sites More sharing options...
Nathan Posted December 23, 2002 Share Posted December 23, 2002 Originally posted by SMW Is there a rough percentage figure by which these temperatures are reduced if you have installed a fmic? To be honest it would be very difficult to quantify. Would the car have one or both cats fitted? Would it have stock or hybrid turbos? What exhaust system is fitted? What make of FMIC are we talking? Would the inlet have a cold air feed....or might it even be an induction kit? Not only that but the percentage would vary vastly between winter and summer. As you can see, to get any kind of meaningful answer you would need a LOT of data. Far more aggro than just saying....'oh, my EGT's are too high..I'd better get an FMIC ;-) Cheers, Nathan TDI PLC Quote Link to comment Share on other sites More sharing options...
SMW Posted December 23, 2002 Share Posted December 23, 2002 Thanks Nathan I had an idea that it would be dependant on other factors. I've already been advised to get an EGT gauge and I'll been doing that as soon as Christmas is out of the way. Quote Link to comment Share on other sites More sharing options...
Adam W Posted December 23, 2002 Author Share Posted December 23, 2002 Righto guys, thanks for all the advice. I went out today and tweaked the SAFC downwards (which raises the fuelcut limit) and the boost controller upwards . . . Fuel cut was previously 1.15 bar, now it's more like 1.35 bar. EGT's have climbed very slightly to 800C, this was at an undisclosed speed on a local test track, lets just say I won't go that fast very often! The car feels "slightly" sharper . . . if I were to put :D :eek: that would sum it up! HOWEVER, I'm not going to get too carried away. I choose to interpret all this as saying "you have enough fuel to make a more aggressive fuel mapping session with a WB O2 worthwhile". When I first put the injectors, turbo and all the other gubbins in the car, I got CW to set it up with his wideband, but I specifically asked for a very conservative setup. Now I feel the need for more speed I'm gonna wind it up a bit. 1.6 bar here I come! Quote Link to comment Share on other sites More sharing options...
Matt Harwood Posted December 23, 2002 Share Posted December 23, 2002 Go for it Adam! You just can't get enough of Quote Link to comment Share on other sites More sharing options...
randy Posted December 23, 2002 Share Posted December 23, 2002 Would increasing fuel into the engine under high boost help reduce EGT? Adam, using Toluene {121 RON} in your gas will definately help prevent detonation while increasing boost! I am simply blown away with the difference toluene made in the performance of my car. Quote Link to comment Share on other sites More sharing options...
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