 Am I running lean? |
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| DavidSweden |
 Oct 31 2026, 03:56 PM
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Member  Group: Members Posts: 485 Joined: 8-June 14 From: Sweden Member No.: 17,452 Region Association: Scandinavia  |
Hello,
Could do with some advice from the D-Jet experts. I’ve fitted AA big-bore cylinders and pistons to my 2.0 914. It’s still running D-Jet and actually runs really well, but I’m worried it might be running a bit lean with the extra capacity. I’ve fitted a wideband lambda sensor, so what sort of readings should I be seeing at idle, normal cruise and under full load? I haven’t touched the fuel pressure since fitting the big-bore kit. Should I increase it, and if so, what pressure should I be aiming for? Thanks in advance |
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| emerygt350 |
Oct 31 2026, 05:40 PM
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Advanced Member Group: Members Posts: 3,802 Joined: 20-July 21 From: Upstate, NY Member No.: 25,740 Region Association: North East States |
Do you have a head temp gauge installed? That is really what you want to watch to determine if you are hurting anything (well that and pinging).
I run 13.7 ish at idle (hot). At WOT I strive for 12.5 and no leaner than 13 but that is really tough and you need to learn how that changes with rpm and what is possible for your engine. At cruise I have vacuum advance and run 16+:1 at 39 degrees advance. That is 70 mph, 3200 rpm. At cruise in most situations under that speed it is between 15 and 16 with the same advance or a little under depending on gear. Head temp at 70 under those conditions stays around 350 on the flats. This is a 2056 with 8.8ish:1 compression. Djet |
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