I mean is there a "perfect" A/F ratio for diesels like their is for gas? Gas is 14.7:1 so I was wondering if there is a similar deal for diesels, us having pressurized intakes and all. Is there a metric that tells/says/shows at what point a diesel is at it's most efficient, meaning - making the most power with the least fuel and EGTs staying in check??

Mikey -

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I dont think so, im not sure but the 14.7 you talk about is the atmospheric presure at sea level...so im pretty sure the turbos aka forced air induction takes that all out of the equation... -

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14.7 psi is atmospheric 14.7:1 is the ideal stochiometric ratio for gasoline. Meaning 14.7 times the mass of air to the mass of gasoline. Anything lower than 14.7:1 is a rich mixture, and anything greater is a lean mixture.

In all my searching, I have never found an ideal stochiometric ratio for diesels. I'm also not sure how you will measure it, because most gauges measure the air/fuel mixture and these are direct injection.
Sean -

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there isnt an o2 sensor on a diesel -

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http://www.dieseldawgs.com/

There is on the new ones -

i thought it was more along the lines of 13.6 for gassers being "ideal" the fuel ratio does exist... talked about it BREIFLY in school but really doesn't have much relevance in a diesel... from what i've learned diesels typically run very lean at idle being that they have X ammount of air which is X number of times greater than the fuel being injected. and well as for richness... the sky is really the limit, no spark plug to flood out. then again you can hurt performance by using too much fuel with out enough air such as bogging down on a no boost take off at WOT -

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One thing i learned in college: DON'T!!! stick your fingers where you wouldn't stick Mr. Happy 89' W250, full fuel 1 1/2 turns, smoke screw flush with the lock, stock pin mildly ground, 1/8th timing bump whole truck refreshing in progress. Soon to be: fuel pin, 366 spring, smooth wall intake tubes once i actually start stock piling some money, turbo and manifold swap, 4" exhaust; 5 if it'll fit. and nozzles.

Well we all shoud know if it is past the ideal stochiometric ratio it will just go as unburned fuel and smoke, but smoke can be fixed to with the correct timing -

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