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Posted: Thu Apr 02, 2009 7:55 am
by coxy321
azzad wrote:Just coz egt and boost guages are the norm doesnt mean they are specifically a better choice does it? If air/fuel ratios are used extensively with dyno tuning they cant be a bad tool.

An air/fuel ratio would also give you good indication of over fueling specifically.

Dazza
I'm pretty sure that the air/fuel measurements are mainly taken for pollution reasons. Thats what i gathered from when i went to deiseltec. An AF meter isn't going to tell you when your just about to hole a piston, that being the reason why they're not so common.

Posted: Thu Apr 02, 2009 6:37 pm
by Dzltec
We use a/f ratio as a tuning and diagnostic tool, along with smoke emmissions. To measure afr on a diesel you will need a wide band 4 or 5 wire lambda sensor. Afrs will go from 13:1 to higher than 30:1 dependant on load and vehicle setup.


andy

Posted: Fri Apr 03, 2009 9:36 am
by azzad
coxy321 wrote:An AF meter isn't going to tell you when your just about to hole a piston, that being the reason why they're not so common.
Im curious to know what you think is going to hole a piston?

Dazza

Posted: Fri Apr 03, 2009 9:51 am
by coxy321
azzad wrote:
coxy321 wrote:An AF meter isn't going to tell you when your just about to hole a piston, that being the reason why they're not so common.
Im curious to know what you think is going to hole a piston?

Dazza
Heat.

Posted: Fri Apr 03, 2009 10:35 am
by azzad
I assume you mean excessive heat; caused from?

Posted: Fri Apr 03, 2009 11:18 am
by coxy321
azzad wrote:I assume you mean excessive heat; caused from?
Overfuelling.

I'm not too sure how responsive an AF guage would be in the circumstance of getting an engine hot (as in how fast it reacts), whereas i know pyro's are very reponsive and are more or less real-time (and most people will have a rough idea of their engines maximum EGT before running into costly repairs).

Posted: Fri Apr 03, 2009 11:27 am
by azzad
coxy321 wrote:
azzad wrote:I assume you mean excessive heat; caused from?
Overfuelling.

I'm not too sure how responsive an AF guage would be in the circumstance of getting an engine hot (as in how fast it reacts), whereas i know pyro's are very reponsive and are more or less real-time (and most people will have a rough idea of their engines maximum EGT before running into costly repairs).
Thats what I wanted to hear you say.

I agree I am not sure how responsive they are which is why I posed the question in the first place.

Posted: Fri Apr 03, 2009 12:04 pm
by coxy321
azzad wrote:
coxy321 wrote:
azzad wrote:I assume you mean excessive heat; caused from?
Overfuelling.

I'm not too sure how responsive an AF guage would be in the circumstance of getting an engine hot (as in how fast it reacts), whereas i know pyro's are very reponsive and are more or less real-time (and most people will have a rough idea of their engines maximum EGT before running into costly repairs).
Thats what I wanted to hear you say.

I agree I am not sure how responsive they are which is why I posed the question in the first place.
I'm sure somebody that actually owns one (on a diesel) will pipe up, or maybe one of the workshops. I only have one on a straight LPG motor, so not really relevant to diesels.

Posted: Fri Apr 03, 2009 6:58 pm
by nissannewby
Thanks for all the input guys yeah the egts on mine dont go above 400 unless fully loaded and fully boosted then can get to around 500 so it looks like the next thing im doing is intercooling cheers everyone