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Re: d16 boosted driving fine without engine management !

Quote:

Originally Posted by underboost

Because we are adding air to the air side of the air fuel ratio with the turbo we must also add a proportional amount of fuel. If there is not enough fuel to compliment the extra air being forced into the cylinders a lean condition will be created which will cause detonation.

Unless you go so lean that combustion can't occur.

Quote:

Originally Posted by underboost

If you want to know what detonation sounds like, take a couple of small ball bearings and put them in an empty aluminum soda can. Now shake the can vigorously and remember that sound. If you should ever hear that sound while driving your car you should avoid the condition (usually WOT, wide open throttle) that creates the sound until you can ascertain its cause.

Let's also remember lean backfires/popping, pingies, inaudible highfreq detonation you can't hear, and engines/exhaust systems louder than the sound of detonation (however it manifests).

Quote:

Originally Posted by underboost

Also be aware that a lean condition makes more heat.

No, stochiometric mixtures make more heat. Lean mixtures create less water vapour, which is what primarily cools the engine.

Quote:

Originally Posted by underboost

The funny thing is that, generally speaking, leaner fuel mixtures create more power.

Negligible increases in power, and peak usually occurs on the rich side of stoich due to inherent inefficiencies in the combustion engine.

Re: d16 boosted driving fine without engine management !

meh its prolly some h/s kid that bought his car boosted and jsut doenst know what the ---- he is talking about

Re: d16 boosted driving fine without engine management !

ermmm, ok sorry about racing on the streets but theres no fukin place to race ere,

:)

Re: d16 boosted driving fine without engine management !

I race on the streets. Many here do.

I do not do it in the rain, I *DO NOT* do it around traffic. It's called time and place.

Re: d16 boosted driving fine without engine management !

Quote:

Originally Posted by Joseph Davis

Quote:

Originally Posted by underboost

generally speaking, leaner fuel mixtures create more power.

Negligible increases in power, and peak usually occurs on the rich side of stoich due to inherent inefficiencies in the combustion engine.

I beg to differ. Just going going from 12.8x to 11.8xx lost me about 4-5% torque. To me, that is not negligible. Going from 10 to 11 for example would make even more of a difference.

Re: d16 boosted driving fine without engine management !

From lean misfire to rich breakup, fuel *with ignition properly tuned* accounts for an average 3% variance in power. Two degrees of well placed ignition timing will do you better.

Noticeable changes in power from small variances in AFR are a good sign of ignition timing fuckage.

Re: d16 boosted driving fine without engine management !

Quote:

Originally Posted by Joseph Davis

No two degrees change in timing will ever change the output that much, unless the timing is way off. I mean by >10 degrees. A/F to HP and timing vs HP are both exponential. Getting closer to the best value nets you less of a gain. Changes in fuel are better though.

Lean misfire is cause by ignition breakup. That is contributed by a weak ignition system or poorly gapped plugs <- catch 22, gapping the plugs down creates a weaker spark.

Re: d16 boosted driving fine without engine management !

im with jd, timing is were all the power is at

Re: d16 boosted driving fine without engine management !

MADMAX, I disagree slightly to strongly with everything except gap is in direct proportion to spark strength - ASSuming constant air gap resistance, which does not occur in turbo, or any, gasoline engine.

You

Re: d16 boosted driving fine without engine management !