So I finally got my VE dialed in pretty close (-5 to 0 in all cells) so I turned the MAF back on.

The VE was pretty far off from where I started, car runs great now.

Boy was my tune whacked. VE was way off, now I can see the MAF was way off too... Way lean in the bottom end, way rich in the top end.

Surging at cruise I had before I started tuning is almost completely gone, YAY !

I'm on my 4th MAF histogram and it's running better and better. Runs great when its warmed up already, but it's stumbling when still cold coming to a stop. It didn't do this with the MAF unplugged. Any ideas what to twiddle ?

Thanks everyone for your continued help - getting closer and closer !

Thanks !
Rob (Bad30th)

 

Dump the maf, its evil.
If you tune, you have no need for the satanic spawn.

 

Bad30th - now that the MAF is starting to line out, how's the drivability compared to SD?

 

Well, it's been a mixed bag... I am still dialing it in but it surges a lot when coming to a stop with cold ECTs. It's been difficult to nail down, sometimes it seems like changes made from logging are throwing it farther out of whack... I've gone back a couple of tunes more than once now.

My gas mileage was horrible in SD mode though, went on a highway cruise and sucked down 1/4 tank in about 50 miles - which is one reason I'm wanting to get the MAF back on and LTRIMS re-enabled to see how the mileage is. I have run through about 4 tanks of gas tuning it, haha.

I am trying out Marcin's MAF spreadsheet today after clearing out the history in it and dumping in my logged data, prior to now I had been using the AFR error % histogram from HPT to dial it in.

I'll post up some more progress here in the next day or so.

If anyone wants to take a look at my current tune or logging just shout.

Cheers,
Rob (Bad30th)

 

Are you still commanding 13.0 across the board tuning in SD mode? If you are, stop it! Command stoich across the board, and let PE take care of the extra fueling. It'll save you a LOT of gas.

 

You mean OLFA tables ? I have under 140 ECT set to stock values and over that to 1.0 (stoich).

My PE is set to enable=0 RPM, table values are :

0-2400 RPM = 1.0 (stoich)
2800-3600 RPM = 1.1 (13.29 AFR)
4000-4400 RPM = 1.2 (12.1 AFR)
4800-5600 RPM = 1.25 (11.70 AFR)
6000-7200 RPM = 1.3 (11.25 AFR)

Remember I'm an FI car so I need the rich AFR at high RPM/load.

Is that what you're asking ?

Rob (Bad30th)

 

If you are an FI guy, you should be doing SD with a 2 bar/3bar setup, as a MAF can cause the car to go lean by looking at airflow instead of boost (you may have the intake tract under pressure, but not be in PE mode which can torch a motor.

SD shouldn't affect your mileage like that.

 

With proper tuning you will always be in PE whenever you are making boost with a MAF. It should always be set it go into PE mode at a lower throttle percentage before boost comes in and is than controlled further with the MAP enable.

 

I have PE enable RPM at 0 and minMAP at 15.

It should almost always be in PE, correct ?

I wonder if this is the reason for the crappy gas mileage...

Thanks,
Rob (Bad30th)

 

That would do it.

 

Hmmm, suggestions then on how to straighten that out without going lean ?

Raise PE RPM/MAP so I'm not always in PE ?

So many things to twiddle...

Rob (Bad30th)

 

do you make boost below 2400? If you can safely be out of PE in that rpm and lower, that will cure most of the daily driving mpg issues.

 

I have a 3400 stall in, so unlikely I would make boost that low...

I could always raise the MAP window too. I idle at 60-70kpa, only time it drops below that is during engine braking and the like.

I will give the raised-enable PE changes a try when I get home for lunch today to pick up the car. (Rode the moto to work today).

Thanks !
Rob (Bad30th)

 

Yeah, I forgot you were an FI guy...you'll most likely just have to experiment with your PE settings and keep a close eye on your AFR to retain some mileage out of boost.

 

I'm finding that the car's sweet spot is about -5 to -10 AFR error % in the MAF table. Any leaner than that and I start getting flat spots in the throttle response.

It's running like a raped ape now, woowoo !!!

I set the PE window higher (2900 RPM @ 75kpa) which should keep me out of PE at cruise and daily driving but still provide a nice safe window of rich PE for anything about 1/2 throttle or more.

I used Marcin (RedHardSupra)'s spreadsheet to get a nice baseline and only did one more log/apply AFR error % and it runs great. Night and day improvement over the old tune in drivability.

I will turn the O2's and fuel trimming back on soon, I'll post up how that goes.

Thanks again for all the help along the way guys.

Cheers,
Rob (Bad30th)

 

Rob,
How hard is the MAF sheet? I have it, but started looking at it and never looked again. I thought if you have a stock MAF, then there is no need to change MAF settings?

Also, on VE tuning, are you tuning LTFT or STFT first? Man tuuning my LTFT took FOREVER. I think I need to go back and scan and retune them both.

Are you using tuners to scan with? I would like to see some of your logs.

Thanks Man!

 

I think we 3 need to get together and share our knowledge

 

That sounds ok to me.

 

tuning with hptuners 2.0 is a snap. On the maf i turned off ltft and used stft. It got alot closer alot quicker! Also, if you dont prefer that method log maf hz vs. dynamic airflow, get a good long log in and then copy the aiflow over to your maf table. Thatll make a good starting point.

 

The MAF sheet is unbelievably simple once you figure out how it works (i.e. ...I actually went through the instructions on the first tab and read them until I understood !).

One gotcha - If using it for the first time Make sure to take out all the old data in the calculations tab (or else you're using the data that came with the spreadsheet - it says that in the instructions).

First log some MAF Hz and dynamic air data. Open the spreadsheet and paste your data into the 'temp' tab, and sort it by MAF Hz. Paste in your sorted MAF Hz and dynamic air data on the front page.

If you are using it for the first time, clear the old data out of the 'old' column on the 'Calculations' tab. Use (Ctrl+Shift+H) to put your data into the 'old' column.

I gathered a few logs and pasted them in to get a nice average before using the data. So start driving and making MAF Hz and Dynamic air logs and putting the data in the front page (sorted by MAF Hz) and it accumulates the data in the spreadsheet. It builds an averaged curve trend out of all the historic data so the more logged data put in, the more accurate the average/curve. Just copy the output over your MAF table, and log again, put the data in, grab the updated table etc.

I can't thank Marcin/RedHardSupra enough for putting that spreadsheet together.

What worked best for me is a combination of this spreadsheet and using the HPT MAF AFR Error % histogram.

As far as 'stock MAF stock table' goes, I have a stock screened MAF and after tuning the VE and turning the MAF back on it was throwing the AFR up to +/- 30%. There were horrible bogs in throttle response, and bad surging at cruise. It would have been pointless to tune the VE and leave the MAF table wrong (unless I just wanted to run SD mode). Once the AFR was brought into line by adjusting the MAF table all the bad drivability issues dissapeared, idle smoothed out, nice smooth power across the board. I am still doing WOT testing.

I am using a Innovative LC1 wideband to do the tuning. It's a lot easier/faster/more accurate of course. Yeah, I spent a couple of weeks off and on tuning the VE. Even with a wideband it takes a while to do it right.

Yeah, I'm using HPT 2.0 EIO. Can't say enough good things about it !! That and the wideband are awesome tools.

The logs are not really much to look at but I'd be glad to send a recent one to ya. PM me with your email address.

Cheers,
Rob (Bad30th)