Wez Posted August 31, 2006 Share Posted August 31, 2006 Hey All, Just wondering what RPM and AFR people run on idle. I try and keep mine as close to 14.7 - 15.0 as i can at 900rpm. Quote Link to comment Share on other sites More sharing options...
Ian C Posted August 31, 2006 Share Posted August 31, 2006 Sounds about right, mine idles at 900rpm and bounces around 15.0 to 15.8 as the stock ECU juggles closed loop around. -Ian Quote Link to comment Share on other sites More sharing options...
Alex Posted August 31, 2006 Share Posted August 31, 2006 14.7:1 - 15.7:1 is common for aftermarket ECU's. Anyone piggybacking the stocker should aim for the stock AFR's as that's what the stock ecu wants...and that's 14.7:1 (well it was on my VVTi.) You have more freedom to try different AFR's on a full standalone. Quote Link to comment Share on other sites More sharing options...
Guest Terry S Posted August 31, 2006 Share Posted August 31, 2006 I run mine at 13.5 - 13.7 AFR. The idle is far happier than @ 14.7 Quote Link to comment Share on other sites More sharing options...
Wez Posted August 31, 2006 Author Share Posted August 31, 2006 Is it good practice to try and get it as lean as possible on idle, that way you are burning off any deposits etc. Quote Link to comment Share on other sites More sharing options...
Guest Terry S Posted August 31, 2006 Share Posted August 31, 2006 I run between 14.7 - 15.2 on part throttle cruising Wez Quote Link to comment Share on other sites More sharing options...
Wez Posted August 31, 2006 Author Share Posted August 31, 2006 Cool, good for fuel ecomony too. I am not sure what i am running, next time i am out I will do some logging. Quote Link to comment Share on other sites More sharing options...
Guest Bijal Posted August 31, 2006 Share Posted August 31, 2006 if you have a totaly standard engine with no cam upgrades or compression or cylinder upgrades then 14.5-15 is fine and almost certainly attainable. when you upgrade with cams or other bits as above its sometimes hard to get good idle, hence you have to run anywhere between 13-14. i had a customers car (2.8L stroker kit with 280degree cams 900bhp R34 GTR) heavily modified and had to idle at 12.8 1000rpm for stable idle it struggled for a nice even idle anything above 13. just depends on the mods you have. totaly stock engines can normaly get away with 14-15 at idle. bijal Quote Link to comment Share on other sites More sharing options...
wkdtime Posted August 31, 2006 Share Posted August 31, 2006 Is it good practice to try and get it as lean as possible on idle, that way you are burning off any deposits etc. With larger Cams the idle can be lumpy, so the afr's will be brought down to 13-14 this is not running leaner, its actually running richer, otherwise the idle will start to hunt and the engine can cut out. Quote Link to comment Share on other sites More sharing options...
dandan Posted August 31, 2006 Share Posted August 31, 2006 What ever the engine is happiest at. I've been through an iterative loop before, richening AFR's, closing throttle more to drop idle speed back down, tweaking ign timing, again closing throttle more. All edging towards getting maximum vacuum at idle - then settle somewhere around that particular AFR. I have one car that idles perfectly at 12.5:1. Off idle or part throttle things are way leaner but that 12.5 gives me max vacuum and smoothest idle. There is nothing to say it has to be anything like 14.7 Also what your trying to do in terms of emissions makes a difference as well. Quote Link to comment Share on other sites More sharing options...
TLicense Posted August 31, 2006 Share Posted August 31, 2006 From an emissions/MOT point of view what should it be? Quote Link to comment Share on other sites More sharing options...
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