40% ??? mine are 55 to 65 at idle....lol
Just numbers/ratios, long as it runs good with respect to AFR/Timing....Let er Rip.

 

I know this is an old thread, but I thought I'd chime in to help some people who might be struggling with this.
To give some background, I do a LOT (nearly exclusively) Haltech cars, more specifically in the Honda Sport Compact drag racing side. World records in all motor on the big stage and a ton of experience with SFWD cars as well and street cars.

I want to give you some quick and dirty tips on how to get your VE where it's supposed to be.
These are not hard-fast rules, but a set of guidelines and tips to get things where they're supposed to be and quickly.

All things here assume your engine config, fuel config etc are all correct and match what's actually happening.

Your idle VE is mostly going to be determined by two things: How much vacuum your engine pulls and the deadtimes/flowrate on your injectors. One of these ACTUALLY affects VE (vacuum), the other skews the calibration on the VE (deadtimes).

Here are the constants:
Most stock port/street port rotaries will want to idle around 45-65% VE. And the more aggressive the port the lower that number becomes, think ~35-40%.
We also know that ALL cars at WOT want ~95-110% VE.

Idle VE Calibration
If you think you should be in the ~50-55% range (because of vacuum), and your car is asking for way more or way less VE and all engine/fuel config is correct youre deadtimes are the culprit.
Here's how I approach the issue.
Set your idle VE around where you think it should be. Turn on O2 control. Start the car, and get it to temp. Turn on all accessories you can to put the most load on the electrical system possible.
Make a number display with the channel 'o2b1 out'. O2B1 Out is your combined STFT and LTFT trims in one number.
Open up your stage 1 fuel injector deadtimes.
Watching the o2b1 channel, follow the trim with the page up/page down until it zeros out. Page up/down = ~10-15%, CTRL+Page Up/Down = +-/- 1-3%.

So if I'm idling and I see the is trimming 10% to target, I hit ctrl + page up ~5-6 times and watch the trim approach zero. Once it's zero'd out, I know my deadtimes are relatively close.
To test, flip the electronics all off and see how far it trims up/down. In an ideal world, it realy wont move past 1-3% or so, but if you start getting over 5% either way when fans or something turn on/off, find a good middle ground in the deadtimes that trims them close with electronics on and off. If you can't get them close, the problem is in the VE table, and your target VE at idle needs adjustment.

WOT VE Calibration
If your VE at max load starts skewing up or down beyond ~95-110% there are 3 main causes. 1.) flow rate is too high or two low. 2.) fuel pressure is dropping 3.) Backpressure
Your VE at load should be the same from wastegate pressure to max boost and require little to no adjustment once the wastegate fuel curve is set.

If your car is running say 140% VE at WOT, we know something in the injector data is off. Deadtimes affect low/light loads, and flow rate affects everything but primarily WOT.
Anything beyond 120% is out of the norm and indicates an issue (always). If your fuel curve is flat 120% through all boost levels no matter where you set it, you need to trim your flow rate under your injector staging menu.

Flow rate inversely affects VE. So if I see 140, I need to trim the flowrate up about ~20% to bring it in spec. If it's 80%, I need to trim it down.

Also, it's entirely normal, especially on engines with enormous exhaust pressures like rotaries to have the fuel table hit 110% VE then trim down to a lower VE as it approaches redline. This is caused by backpressure. Your number you're looking for is MAX VE, not trying to get 100% from 2000 to 10,000 RPM.

When you start trimming flow rate, you will likely need to address the VE table again at low and light loads depending on how much % you trim it. Flow rate affect the ENTIRE fuel table. Deadtimes (mostly) affect the lower end of the fuel table. If your deadtimes are WAY off, you will see it skew your WOT, but this is a rare case.


Other
I also saw someone make a comment about VE at stoich. Just want to address and clarify. Your VE has NOTHING to do with Target Lambda. If your VE table/Engine Config/Fuel Settings are tuned correctly, you shoule be able to set target lambda at any number and the ecu will hit target lambda with minimal trimming (under 3%). I should be able to set target lambda to 11.5 or 16 and the computer should hit it, if I change my fuel type from pump to ethanol or methanol, the VE table should require no adjustment whatsoever.

Lastly, like I stated at the top, these are just quick tips, not hard and fast rules. Don't stress over getting overly granular. At the end of the day, whatever makes the motor happy is best. But HUGE swings beyond the numbers I laid out indicate problems that need to be addressed.

Another note, fuel tables should in general have smooth transitions from idle to wot. A dirty way to tune fuel for a basemap is to set your idle VE around whatever you think it should be, then at wastegate pressure, build a curve with 110% VE at the most, then do some interpolating. In general, you'll see the curve doesnt change much from this, maybe +/- 10% in some areas, but it will be smooth and gradual low to high, then level off at wastegate and be flat from wastegate pressure to max boost.

If you see the curve be high at low load, then dip, an raise back up again, deadtimes are an OBVIOUS issue. Some really bad injector companies send fake data and this is the easiest way to tell lol.

Any other questions, ill be glad to answer.

 

Great explanation, thanks for sharing. That all makes perfect sense!


Looking back, after personally working through this; if I ran into this situation again I would load a base map, get it "running", and start with the dead times until I'm close to the target AFR at idle. Then I would rough the map in and watch the trend, using flow rate to adjust the VE higher up in the map.

I was initially quite opposed to the idea of changing the data from ID (they are wizards of course, so the data must be right..?). This resulted in a lot of wasted time making small changes to the injector setup and the VE map simultaneously. I now trust the process more, and would head straight for injector characterization if the idle VE is out of whack. Got another Elite 1500 to tune coming up, interested to see how that one turns out. Hope to use ID injectors on it too.

 

in my experience, ID data is pretty rough. The short pulse width adder data is usually useless. But flowrate and deadtimes will usually get you relatively close before fine tuning.

ALL 2000cc injectors ID or otherwise are all over the place and my rules above barely apply to them. Car might idle at like 30% VE and WOT will be 140% lol. I’ve stopped even trying.

ID uses a motec and ‘simulates’ haltech to
produce their deadtime data. So the data you see on their spreadsheets are not actually found using a haltech and explain the discrepencies.