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Dec 25, 2017 | 08:16 PM

darreldanger

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VE VS Comp

If I increase compression how much if any will it affect my Volumetric efficiency?

Dec 26, 2017 | 01:21 AM

Sarhan

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Joined: Jul 2016

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From: Kingdom of Bahrain

No guessing over here you need to retune your VE

Dec 26, 2017 | 11:24 AM

FLTRI17

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VE is affected anytime airflow is altered. By increasing compression the airflow changes so recalibration is necessary.
Bob

Dec 28, 2017 | 05:37 PM

darreldanger

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Quote:

Originally Posted by FLTRI17

VE is affected anytime airflow is altered. By increasing compression the airflow changes so recalibration is necessary.
Bob

Yes but I don't think airflow is affected by comp...

Dec 28, 2017 | 07:05 PM

FLTRI17

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retracted

Last edited by FLTRI17; Dec 28, 2017 at 07:09 PM.

Dec 28, 2017 | 07:27 PM

jbarr1

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From: georgia

Listen to Bob. It most definitely affects airflow.

Dec 29, 2017 | 11:02 AM

hrdtail78

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From: Alorton, Illinois

If it affects airflow or not isn't what would concern me. How compression affects the efficiency of the air fuel ratio is what would concern me. Adding compression can also affect things like squish, flame front travel, and atomization of the fuel. This can and will affect air fuel ratio. Besides, with added compression. Wouldn't one want to address the timing side of tuning as well for all the same reasons?

Tale of two 124's. Both have same cam, static compression, and lower output. One has shaved heads and flat tops. The other has 7 plus cc domes. Timing different between the two is 7-9 points. There is more to tuning than adding and subtracting fuel based on compression values alone.