A recent situation came up when doing a tune. It was one of those things where someone had done some mods but needed a tune to get things going. I helped out and provided some remote tuning. The VE map is not "smooth" and is fairly
bumpy in places. However, datalogging and driver input indicates a very driveable tune.

So my question is, Does it matter to you that the VE map is not a nice rolling, smooth curve? I recall Grumpy saying that "give er what she wants".
What do you think?

 

I have found smoothing doesn't allways help. Feedback from helping people tune there ve spiked ve ended up being the answer to a better running engine. Go figure factory ve are pretty smooth .

 

I've tried smoothing (both manually and otherwise) and whenever I go back out to datalog I find the VE wants to revert back to a previous mode. Of course there will always be cells that are not touched or logged causing some of the peaks or valleys.

 

I agree with Tuned... give the engine what it wants. I don't drive around thinking how smooth and pretty my VE tables are...lol..

 

It would be nice to have the tables look pretty . But if it's effecting drive ability ugly it is lol

 

I concur. Smoothing fuel is typically not true ideal. No engine flows perfectly but I'd love to see f1 fueling graphs.

 

i agree as well. my engine seems to only be happy in the 13.5-14.00 range. anything above that it feels like a sluggish puppy. Hell my old 305 tbi had a VE map that looked like the Rocky Mountains but it ran like a scolded dog. my VE map for my 383 looks much cleaner but im still dialing it in.

 

yes precisely. and when looking at stock bins from GM, guess what? They weren’t nice and smooth. They were jagged, and some parts and regions of the VE map were incongroous with the rest of the trendline. And yet, the datalogs show BLMs averaging 128 +/- 2. Motor running smooth as hell. That’s the smooth that counts.

 

For me, If the ve is not smooth and progressive I think something is out of spec. My personal VE and many of the 100's of datalogs i've tuned meet this spec. While I've had to tune these eratic logs spoken here. Many have to be revisted once the problem is found and solved. IMHO, if you suffer from eratic mapping you have an issue you need to solve.
The datalog has a lot to do with it as well. they should start with a fully warmed vehicle to go closed loop ASAP and driven for at least 20 minutes to get a fine tune.
Also, dial in the flow rate first. Read the o2 at WOT for rich or lean and adjust this first prior to any VE or MAF table work. Short logs in the beginning are okay but at the end they should be as long as possible.
I had a guy send me 9 datalogs the other day and get pissed off when told I can only use one. One good long log is far superior to multipule logs when you have to choose one to use.

 

I agree.

I personally havent seen a ve table that wasnt relatively smooth and reflect the engine power curve for the most part.

Now sometimes can be slight variances in the table due to where cam/intake might start working together to make power, esp on big cams and such but its not really a spike in the map