Smoothness of VE map

Hello,

I'll jump right to the question,

What is the consensus on the smoothness of VE maps?

Many advocate that VE maps should be smooth and without "hills and valleys"; however, some cars do tend to have these regions of high and low VE.

Now, should we aim to smooth out the valleys (artificially bump up the VE there) and maintain the hills? or add extra break points in those regions and further test the engine? or just leave the engine VE the way it is?

And what is the actual underlying issue with having these rapid changes in VE? Will it affect the stability of the injector and fuel flow?

Hope you guys can chime in with your valuable expertise.

If an engine has VE shape due to cam, intake or exhaust resonance and response you should give it what it wants.

Provided you aren't trying to mash significant issues like fuel pressure hammer/pulsation into the VE map, there is a reason you have a table with so many points.

VE map is kinda smooth by default with a level of extrapolation to some extent. Since it represents how good engine inhales air over RPM range it has to be smooth as in most cases the air can't just appear in extra large quantity all of the sudden out of nowhere. Of course peak torque area will be very noticable but still it should be something that looks reasonable in connection with areas below and above peak torque RPM. Basically your VE map is almost identical to your torque curve on the Dyno sheet.

Maybe the overall shape of the VE map (the outer perimeter i guess) would match the torque graph, but would the other areas experience the same smoothness?

Of course they would - that what I was trying to explain. The air delivery increases and decreaseds smoothly through out engine RPM range. There are might be peaks in air consumption (like peak torque or aggressive camshafts) but majority of VE table is very reasonable in numbers making it look pretty smooth.

That makes perfect sense Shota, so from your experience, most VE tables do look smooth and match their torque graphs

Yes, that is exactly my experience. I picked it up from Greg Banish book- he is one of tuning gurus so I've been using his wise advices all over my builds. Picture from his book is attached.

That is definitely a great book, and it seems that I have to reread it.