yobabiesdaddy2001

iTrader: (20)

If the values in the VE table are calculations of how efficent the engine is at a certain Rpm vs Kpa cell then.... by looking at the table and comparing it to other vechicles VE table you should be able to decided wich combination is more effincent at a given range wright?
Please explain
thnx!

Tordne

IMO there are too many variables that would invalidate this. The first is the IFR table of each vehicle. If your table is out by say 2% you will have compensated for this in your VE table to get your actual AFR in line with commanded.

Imagine that the person you are comparing against has a similar discrepancy then the numbers are meaningless for comparison.

RedHardSupra

iTrader: (1)

yup, Tordne got it about right--the VE table is generally used as the catch-all fudge factor, thus using it for comparison is unfortunatelly moot.
i've been working on isolating all other errors to eliminate the need to fudging with VE, but the system seems to be designed in a way that doesn't really allow for the VE to be a true theoretical VE. which, frankly, blows chunks.

theoretically, you're absolutely right tho, VE should be the best way to compare efficiency, power, and powerbands.

the way we have it working, you can only use it for observing relativistic changes on your own setup only. every car has too much slop to estabilish a good solid base necessary for comparisons.

yobabiesdaddy2001

iTrader: (20)

So RedHard, your saying that since all cars are different (easily put) then my VE values are only good for comparing my upgrades to previous setups in area's such as effciency , power and powerbands?

black_z

iTrader: (4)

Exactly, the changes in your VE table will give you an idea of how upgrades changed the efficiency characteristics of your engine and at what areas of the powerband.

SScam68

iTrader: (20)

Not efficiency, just "VE".

Calculate BSFC if you want to know how efficient your setup is.

brad8266

iTrader: (23)

RedHardSupra

iTrader: (1)

well, BSFC is a combo of fuel consumption and hp. VE affects both, so it's a good starting point for comparisons. the best measure of efficiency is BMEP, which is torque and displacement combo, and since torque is compression, and compression is airmass, and airmass is calculated from VE...i just use VE

SScam68

iTrader: (20)

Just to clarify.

BSFC = (fuel consumption rate)/(brake power output)...bang for buck if you will.

VE (true) = (Mass of air consumed)/ (mass of charge if cylinder were completely filled)

BMEP = (brake power output)/(sweep volume*rpm*number of cylinders)

I think I understand what you're trying to say in the last portion of your statement but it makes no sense.

There are a couple different ways to compare an engine's performance, even if they're totally different setups.