Basic VE/MAF Tune

[RevGTO]

Is there a way to do a "basic" "simple" VE and MAF tune without doing the complete AutoVE process? If so, can someone give a step by step instructions as to what to log, MAPs to create, etc.? This is for a bolt-ons car that is running lean. We have an LM-1. I find references to doing this, but being a tuning newb, am not clear as to how to go about it.

[Bruce Melton]

There is a good tutorial on doing it "right" with Auto VE. then dialing in MAF. Buy the time you pick up all the knowledge pieces to tune it piecemeal I think you will realize it is too late.
Take it from a guy who fought it the hard way for a few years, you would be well ahead taking a few days and getting it done right. I am a MAF guy but many here disagree on the need to put that back in line. Depends somewhat on your climate "me thinks".

[Beer99C5]

There is a good tutorial on doing it "right" with Auto VE. then dialing in MAF. Buy the time you pick up all the knowledge pieces to tune it piecemeal I think you will realize it is too late.
Take it from a guy who fought it the hard way for a few years, you would be well ahead taking a few days and getting it done right. I am a MAF guy but many here disagree on the need to put that back in line. Depends somewhat on your climate "me thinks".

What Bruce said.

I am taking my time doing the VE table, I pretty much have the Bens' @ .98-1.00, some cells are hard to hit, others 30 and under MAP are the decel area's I had trouble with those too. Once you have the VE done, use the same VE tune, turn the MAF items back to stock (plug it in), add the MAF freq PID, set up a Map per the Maf tuning thread (started by Black02SS) and log Ben's and apply the changes to the MAF freq just like the VE tutorial.

Dont make the same mistake I did, I turned the MAF on after getting the VE ballpark; and then used the Bens and applied them to the VE table and the MAF table :bash:

Do the VE first.
Then the MAF.

Beer

[Tordne]

Also, if you are going to use a Custom OS version 3 or 5 set the values in the B3647 table to something other than an EQ Ratio of 1.00 (14.63:1 AFR) or Semi-Open Loop will be enabled and trimming will occur - which you don't want while VE tuning!!

[Garry]

Sounds like that's something that needs to go into the AutoVE tutorial, Andrew!?

[Tordne]

It been a long time since I looked at to be honest, but yes it definately should (if it isn't already)!!

What would/should happen if you leave the B3647 table as EQ of 1.00 (14.63:1 AFR) and enter Semi-Open Loop is:
- Say you increase your VE table by 2%, you should see that the BEN will stay the same but the fue trims will reduce by a further 2%

This is because the O2 sensors will be switching to try and maintain the 14.63:1 AFR (Stoich).

I've seen some peoples tunes where they have done an AutoVE and have enabled the MAF and see LTFT trims of -20%. Looking at the VE is is just insanly high and this is often the reason why - at least that's what I've found.

Cheers,

[Garry]

The one I used I think didn't have any references to COS3/5 or this table - the website has it dated October 05, and a search for "3647" in it doesn't turn up any results ...

So, what value would need to go into 3647 (or somewhere else) to disable the COS from using it during AutoVE?

[5.7ute]

A few of us have asked the same question. Tordne goes into it in the cos thread titled B3647 questions. I also set B3618 PE modifier based on rpm to 14.7 instead of 14.63 or EQ of 1.0 as stated in the tutorial. Some of the experienced guys will know if this is necessary or not.

[Tordne]

Provided you have all the other settings correct to disable Closed Loop fueling then setting the B3647 table to anything other than 14.63:1 (1.00 EQ Ratio) will cause the fuel system to be in full Open Loop and trimming will not occur.

I started out using % VE and AFR for display units cause it makes more sense when you are starting out. I made the change to defaults for both VE and AFR and am now totally used to the units. This has no bearing on the above, it's just a side comment. I also made a spreadsheet that helped with the transition from AFR to EQ Ratio..

[RevGTO]

So then you guys are agreeing that an AutoVE tune would be the way to go for a basic bolt-ons car?

[VetPet]

I'm fairly new to the tuning world and this year was the first time I had a chance to actually use my tuning software after I finally got my WB02. Any bolt on that increases the amount of air entering or exiting your engine means changes to the engines VE and that means tuning your VE table, especially if you're going to run in speed density mode (mafless). I chose to keep my MAF which means having to recalibrate the MAF as well. In either case, properly tuned VE table and MAF mean your LTFT's won't be adding fuel under WOT operation. Now when you tune your PE table for WOT you will have the true afr based on the engines VE rather than a blended number based on additional fuel from positive LTFT's.

I'd certainly tune your VE table since you've already got the software. Your additional investment will be the WB02 and once you've got it you'll be ready for tuning for any additional mods you make in the future. It would seem to make sense to learn how to use the tuning software with the more simple bolt on mods and work your way up.

:cheers:

[5.7ute]

What would you guys consider is close enough with the VE bens before turning the maf back on. I ask this as here in the middle of the desert it is near impossible to get all the bens closer than .98 to 1.02. The temperature is fluctuating between 32 & 42 degrees C during the day & changing the IAT by up to 30deg C.

[TAQuickness]

+ - 0.02 should get you close enough. COS3 or later has an IAT scaler to help you with those wild temperature swings.