maikonkun

I did a few runs today in 4th gear at WOT to see what kind of AF ratios I was getting. I have attached 4 graphs here, 2 are of the stock ECU - that is the UTEC set at Map 0. The other 2 are made from the Evo map posted on TurboXS's website, which I loaded at map 2 on my utec

The first question I have for everyone is that all the runs show AF ratios of over 14 from 2000 rpm to 3000 rpm. From my understanding of tuning theory, maximum power occurs at 12:1. So why would the stock ECU use 14 plus ???

Anyone else done an A/F plot like this and got similar results ?

Moving onto the TurboXS maps. As you can see they exhibit the same 14plus A/F from 2000 to 3000 rpm. But what I think is a little scary is the fact that it is running 12 plus A/F from 5000 rpm and up . In fact, as I posted in another thread, if I run a slightly dirty stock air filter, instead of the drop in K&N I had on these runs, I do in fact get knock

Another point to note about the TurboXS map is that A/F's seem to be a little unstable from 5500 rpm plus. Wheras the stock runs are relatively smooth. This makes me wonder if this is a result of the unstable MAF readings and unstable load point readings I often see. What I mean by unstable is that even on a simple WOT run like these, where I have my foot to the floor all the way to redline, I often get readings like :

RPM MAF TPS Load Site
6361 1479 100 80
6410 1396 100 70
6447 1474 100 70
6497 1412 100 80

As you can see the MAF readings are up and down, and the load site is oscillating from 80 to 70 to 80 %. From a simple examination of the data, I'd say the UTEC can't make it's mind up how much air is coming in and so how much fuel needs to be added. The Stock ECU on the other hand seems to handle the fluctuating MAF readings with no problem and has no A/F oscillation like the UTEC MAP does.

Any theories ? Opinions ?

MalibuJack

iTrader: (5)

Your seeing similar results to what I was experiencing.. 4th gear runs are hard because of the speed you end up going, I'd suggest doing it in third gear, but your results will end up being the same..

Anyway, the MAP1 that comes with the UTEC is not really optimized well for any mods that I Have on my car, but you'll find on almost any wideband pull that your "Tip-In" AFR's will be lean until it gets into a load site with adequate fuel compensation. I actually think this is fairly unique to a dyno run since it doesnt go that lean when I log the data running through the gears.. Basically you need to tune the load sites for your tubo spool-up since every mod you make places the spool rate in a different location..

I do know that if the MAF reading hops around, it will tend to want to stay in the next lower load site, so you'll periodically see it jump up to the next one, then drop down, then finally go up.. Its transition point between the sites. I do think that the values don't drastically change since the transitions are smooth and not "Jumps" between load site values..

Also, keep in mind the TURBOXS Stage1 map has some timing modifications which don't seem optimized for many of our cars.. (I experienced a severe loss in performance due to the map having very VERY lean in spots, pretty rich in others, and overall unaggressive timing)

A few suggestions for you if you haven't done this already..

Lower your MAF MAX setting to fall a few hundred HZ lower than the max maf your seeing, it will make WOT tuning easier since it will spend more time in your 100% load site..

If you have an aftermarket air filter and MAF pipe, the tip-in AFR's will typically be pretty lean until around 4500rpm, and you may find you'll have to add quite a bit of fuel across the board. .. You need to first put your fuel compensation in to the cells that your pulls fall into most, then "Fan out" the values to all the adjacent cells.. Also, do several pulls in different gears, and do a run through all of the gears.. then take the data and find where you have lean spots, or rich spots.. once you get everything into a state that seems to be most consistent, you can then address modifying your timing.. If you want to run more aggressive timing than stock, you should try to target a fairly fat AFR (11.2 or so) then using all the data you've logged, look at the load sites your hitting, and the timing that the car's ECU Wants to run at.. use that as a starting point and add or remove timing one or two degrees at a time.. once you get something that feels good and is repeatable without knock, you can then remove a small amount of fuel.. basically you keep repeating the process until you get a fairly rich, smooth AFR curve, with timing that prevents knock, but provides you with good power..

Since you do not state what mods you have, I cannot offer you any advice, but looking at your AFR plots, it seems that you have an aftermarket intake, MAF pipe, and exhaust upgrade at the least..

you will never get a totally smooth AFR curve, and the MAF readings with aftermarket components will jump around a bit.. The key is to make your changes between cells gradual or gradual enough so there's no severe change (unless necessary) in fuel or timing.. The UTEC will average the values between the two so its really just a method of allowing for smooth transitions..

Another good way to look at things is to examine your injector duty cycle, timing, and MAF on the same graph with your AFR along with RPM and Boost.. since you will very quickly see what your car wants by plotting all that data together. I also throw the Load site data on there to see what point I'm at..

the absolute HARDEST part to tune on a car is the low load "Tip in" AFR's since no two runs will offer exactly the same MAF readings and possibly load site at those points.. if you have an aftermarket MAF pipe and AIR Filter, lower airspeed due to lower restriction, plus turbulence from the Filter into the MAF, and even the "Backflow" of the Recirculation of the DV can disturb the MAF reading hence some trouble tuning.. Therefore the real trick is to find a "Fat mixture" that works, and do it for all the load sites across the board until you get past the lean point.. and refine that until you get a good consistent curve no matter what load site it ends up in..

3d tuning is a bit difficult since external factors can and will always put you in a place you don't expect to be in..

maikonkun

I've been playing around quite a bit now with the a/f ratios and so far I have been moving in the direction of moving the a/f ratio close to 12.0 to 1. The closer I get to 12:1 the more power it seems to deliver. Which if you believe the adage that max power occurs at 12.0:1, is what you would expect.

I know by doing this I run the risk of getting knock, but so far running the stock ECU timing I am getting no knock what so ever. When I have got my current fuel map set up for max power as close to 12:1 without knock, I plan on playing with the ignition map.

I was just wondering I am treading a familiar path of utec tuners before me, and if so what was everyone's experiences / pifalls ?

Tips advice on going this route ?

MalibuJack

iTrader: (5)

The real reason for caution running that lean on a turbo car isn't simply to avoid knock, but to avoid unpredictable issues such as bad gas, runaway boost, or spiking, or some variable that could cause your car to run lean enough to melt things.. lean AFR's and aggressive timing curves melt motors..

Eric Lyublinsky

iTrader: (5)

maybe the stock ECU is flying between two diffrent maps?

Nice features but does it work right?

MalibuJack

iTrader: (5)

when you allow the ECU to do the timing there's a possibility, but you would register knock before it switched maps.. however when you control the timing with the UTEC, its absolute, and the ECU igoing to a different timing map won't make any difference..

And yes, it does work right, I get no audible knock in most scenarios.. and not enough when I do to trigger a map switch.. Don't get me wrong, there are occasions when the stock ECU might slip into a conservative map, there are days my car feels weak, but once you control the timing with the UTEC, the map doesn't matter.

maikonkun

Thanks for the advice, I definitely want to err on the side of caution. But therein lies my problem. As I mentioned in the beginning of this post, depending on which gear I do my WOT run in, the A/F changes. So if I set my A/F to be close to 12:1 in 3rd gear, when I do a run in 4th gear, it is usually half a point less ( eg 11.5:1 )

Considering I am still not getting knock even when skirting 12:1 in 3rd, I am thinking, the 4th gear run is the more accurate of the two because you get so many more samples, and the change between samples is not as quick.

MalibuJack

iTrader: (5)

You should do a run through all your gears under load (as you would a 1/4 mile run) and see what your AFR's are.. you can then see the load sites, MAF reading, and AFRs.. this will allow you to target appropriate load sites for the conditions of a real run..

nothere

iTrader: (23)

MJ,
concerning maikonkun's idea of leaning out for more power, wouldn't a knock count (in case of an emergency) cause the utec to add fuel or pull timing?

maikonkun

This is basically what I was thinking - the ECU or UTEC for the most would catch the knock and take care of it, but as MJ says there's always the proverbial wrench in the works suddenly appearing to mess that up.

Also another thing that led me down this line of thinking was when I tried the Evo Utec map posted on the TurboXS website. It's supposed to be a conservative tune that won't mess up your Evo, but my experience with it gave me really bad knock and very lean A/F ratios. I think MJ also had issues with it.

MalibuJack

iTrader: (5)

Yeah, it was real lean in the midrange on my car.. and had very odd timing..

Just remember the knock count should never be used as a safety.. It will pull timing 1 degree at a time until the knock stops, the problem is you'll never catch severe detonation in extremes fast enough to prevent damage.. so tuning on the edge is not the safest way to do things.. plus you won't gain much more power if you're working with timing and AFR's


EDIT:

This is to clarify something.. I posted an incomplete thought here because I was rushed.. What I mean by not gaining more power if your working with timing and fuel is the level of tuning that you do, if your at 11.5 afr's and you have a decent bit of timing that does not cause detonation, leaning it out any more will not gain much more power, but increase the risk of a problem should you have a problem such as bad gas, boost spike, etc..

Timing and Fuel curves are very closely related, you need to balance timing with the fuel to get the lowest EGT's possible with the best power possible.. More is not always better and can do damage.. Its a balance between the two..

Imprezd

You have to remember that you are using a BASE map. By no means should you think the map is for peak power. We are giving you a place to start from. Also the map is for a Stage 1 Vehicle. So if the utec is your only modification then that will be close to the situation it was tuned for.

As far as the MAF readings, the values are interpolated. So even when it does switch load sites it not totally switching the way the car is fueling itself.

The main problem you will face is that when you get a knock it makes the evo switch fuel maps. So if you knock and you are on the hi det fuel map, and you are tuning to a 12:0 AFR and then the car decides to get happy and switch back to the lo det fuel map your AFR can jump easily by half a point leaner. A good rule of thumb to find out where you are usually is reflected in the ignition timing during spool up. If the ecu wants to run 2 and 3 degrees of timing you are pissing it off pretty bad. We've seen the ecu want to run negative timing.

Good News is:

The new software fixes this problem by basically the UTEC will make the fueling decisions under load. We are making the decision on pulse width not the ECU.

End result is:
Fixed Fueling + Fixed Timing = HAPPY TUNERS

Malibujack email me... I will be needing your assistance.

Later Guys,
Jermaine@turboxs.com
www.turboxs.com

jason9080

I am getting Utec w/stage 2 map, do you know what stage 2 is currently setup with? are they all setup with stock? You suggest not to work with AFR and timing but aren't they most useful features utec have? also do you think I can adjust boost level with utec? have you done it?

jason9080

I am trying to get the combo they are selling on here, it says utec with base stage 2 map, what does that setup with?

Imprezd

No where did i suggest not to "work with AFR and Timing." Fixed Fueling and Timing meaning... using UTEC Values Not ECU.
The utec is fully capable of controlling boost.

Thanks,
Jermaine@turboxs.com
www.turboxs.com