16g tuning questions

I am posting this for 95ClipseGS-T. I have been trying to help him set up his SAFC-II and we are having some problems. He has a 16g @ 13psi, 190 FP, 550cc injectors, turbo back exhaust with test pipe, MBC. I was able to talk him through getting the samples/second up on the logger. He was tuning based on the RKO website and here are the problems.

1. He is getting a "catalyst efficiency bank 1" DTC. I figured this was because he still had the rear 02 installed in the test pipe. I told him to remove it, wrap it in foil and clear the code.

2. He is getting fuel cut. I have read that this is not normal with his mods. I advised that he do an intake test, which seems to be the most common cause of fuel cut.

3. After setting the AFC based on the injector size, then you start adjusting the AFC based on the STFT and LTFT. Acording to RKO you free rev to different RPM's and check you trims, make adjustments on the AFC and then let the car idle to see what the ECU does with the trims. Here is the question: How do you know that you are correct, do you look at the trims at idle or do you need to free rev and check them at the individual RPM points.

4. Is it ok to check the trims while you are driving (I know, have a friend in the car so you don't wreck). Can you just drive down the road at one of your Ne points (let's say 1500rpms) and adjust based on the fuel trims or do you need to free rev (no load).

5. What happens if you have the trims correct at, let's say. 1000rpm's and 2000rpm's (i.e. 0%) but in between where you have no Ne point the trims are lets say +7? What do you do then.

6. When you pressure test the intake will this move the boost gauge?

If the answers for some of the questions I gave him are incorrect, please let me know. If not, any help would be appreciated.

I would have put this in the last post, but it was getting kind of cluttered up there. Here is his latest log:

http://files.automotiveforums.com/gallery/watermark.php?file=/503/155962untitled.jpg

Don't the O2 voltages seem a bit high?

He said that he hit fuel cut 2x during this run, but I don't see any indication in the data. I still don't think he is getting enough samples/sec out of the logger (maybe he was logging too many paramerers, I removed the ones that wern't needed).

He also logged STFT & LTFT, which were LTFT = 0 across the entire run and STFT was at -4 the entire run. Fuel trims aren't used during WOT are they?

Please help. I can see by the timing advance being so low that there is a lot more power to be milked out of this turbo!!

First, if you are making a WOT tuning log, dont log trims. They just cut into your samples/sec rate. Get the trims right first. For #1 and 2 you are right on. You can certainly set the trims while you drive, and this is really how you should do it. By just reving in nuetral you dont always get the full increase in airflow that you get while driving (load), so checking trims while driving is more accurate and will refelct the driving conditions better. The thing is trims dont change very fast, so its often hard to keep a certain rpm for long. Most often you'll find that the adjustment on the low map is the same across teh board as long as you havent hacked the MAS. So if -18% gets trims right for 1k rpm, and its good for 3k rpm, just set all points to that amount. For the high table you can copy over those values for starters, or use the injector compensation figure only (stock injector divided by new injector minus 1). Pressure testing will move the boost guage, if you dont have a massive leak :D

The l looks fine until O2 drops to .88 there. Theres no way hes out of fuel with 190/550s, so I'll assume thats where it hit fuel cut. 30 lbs/min is very high for 13 psi, I'll bet a 6 pack hes got boost leaks. For reference 30 lbs/min is the max a 14b will do, so the car should be moving. ;) Timing never rises either.

To put it simply, if air metering and fuel delivery are all what the ECU "expects," just putting in the injector compensation will result in stock like conditions. PErfect trims, for example. But even on stock cars trims are rarely 0. So there will be a little tweaking. My point is that you dont want to "over tune," the ecu knows what its doing. If you have to put in crazy numers to make it work, something is wrong. Its that simple. For WOT, stock situation (just injector comp) would be 9.5:1 AFR, VERY rich. So there is typically some power to be had by leaning out a little. I shoot for 11:1 on pump gas (another 10% leaner or so), but with sidemount IC and smaller turbo, you'll need to be richer to avoid knock. So start with the high maps at injector comp only and see how it runs. If timing and all that look good, lean out 1 or 2% at a time, until timing gets banjaxed. Timing may get higher for a while, since the leaning out adjustments on the AFC will LOWER the airflow signal sent to the ECU ;) Which reminds me, if he is at ~18% on the AFC, hes really flowing 18% more than 30 pounds/min. At 13 psi on a 16g? Boost leak. :)

Hopefully that gets you started. Get a clean log with no fuel cut to 7000 rpm and we can get more in depth with it.

I Bow To The Ol Mighty All Knowing Dsm God!! :worshippy

thanks i'm going check for leaks tonight at one of my friends house and remove that rear o2 sensor and make a pull or two.

my new palm should be in the middle of shipping right now, and i already got the stuff i need to put pocketlogger on it ;)

just a warning cuz my questions are soon to follow :D

lol, well I hooked up my boot leal tester and found like 3 r 4 small leaks. Hopefully it fixed it. I couldnt try because it was pouring down raining and any of you turbo'd knows what happens when the boost kicks in on a wet road. :)

I couldnt try because it was pouring down raining and any of you turbo'd knows what happens when the boost kicks in on a wet road. :)


Yes I know what happens, I still hook up! :smokin: Oh wait, I just realized your wrong-wheel drive ;) . Nevermind :biggrin:

My car goes ass end out in the rain in 3rd gear when boost hits :lol: Scary though, since I'm going like 80 by that point.

Ok well I found a few little small leaks, had to use soapy water to see them. dont know if i found all of them but Im still getting fuel cut(or something like it) whats funny is it only happens when im in a higher gear than i should be and go WOT. if i take of from a dead stop it runs fine but sometimes i feal a little like sputter when i quick shift to third. This weekend im going to undo all the icp and re silicone the BOV and gasket flange and the Turbo outlet and gasket flange.

also this morning when i was on a wet strip of road and WOT from 2k it went to redline with no Fuel cut. I dont know whats the deal with this damn thing. The day i installed the 16g it started getting this fuel cut or boost leak. ive messed with the icp and connections a few times thinking it would fix it but nothing. I may try to maybe turn the boost down and see if it still does it. I just dont know anymore. :banghead:

Here are 2 of the logs that cecil sent me. The first one looks like a decent pull, but the ECU is jacking the fucking timing!!! The second one just looks all fucked up?

http://files.automotiveforums.com/gallery/watermark.php?file=/503/155962Run_1.JPG


http://files.automotiveforums.com/gallery/watermark.php?file=/503/155962Run_2.JPG

HELP!!!

Ok, we were able to get the fuel cut problem solved. Apparently when he tuned for STFT & LTFT it only put him in the -2 to -5 range (Weird??) and according to the RKO tuning guide that meant to carry those numbers accross the board in the hi throttle settings. We used the injector compensation formula and came up with a baseline of -18% on the SAFC for the hi throttle settings. Bingo.....No fuel cut!!! Is it normal for the lo throttle settings to be that close to 0?? below is the latest log. He still isn't getting the timing advance that he should be (I read +16 degrees). And I am seeing low (?) o2 voltages. I know that you can't tune for o2 without a WB, but can you use it as a guide. I looks to me like things need to get a little richer. Is that true.

http://files.automotiveforums.com/gallery/watermark.php?file=/503/155962run_3-med.jpg

any suggestions Kevin.

i wanna know why you still arent goin to redline? STOP BEING A PUSSY AND HIT REDLINE! lol seriously

that last log looks pretty good, although the first 2 seem as if the computer was seeing knock so the timing got pulled all to hell! add more fuel/turn down boost to get rid of the knock, alteast you have not more fuel cut!

lol, where does the rev limit kick in

7500! NOW GO HIT IT! go on. then post your log :flipa:

k tomorrow mornig on my way to work

16g will drop airflow high, but it might still be worth it to go to 7500. I'd get a good tune to 7000 before a great tune to 7500.

You think tuning is hard on a 16g....try a 60 trim :flipa:

add more fuel/turn down boost to get rid of the knock, alteast you have not more fuel cut!

If I remember correctly, it is safe to boost 18 or 19psi on a 16g with his supporting mods on the SMIC. He is only running 13psi. Is adding fuel the only option other than turning down the boost?

i dont know alot about air/fuel tunning, but that timing looks preatty low for what you have. what is your base fuelpressure, and base timing?

Sorry guys, I havent checked back in a bit.

There are many things that affect fuel trims. I wont even begin to list them all. Every car is a little different, but if you have to stray more than a few percent from base injector compensation, something is wrong. In my case, I just go with injector comp and drive it the hell on. I adjust for WOT, and to hell with trims. But thats because I Can trust my air metering and fuel delivery because I keep close tabs on them (WBO2 vs calculated AFR).

I would pull fueling back by 5% (so minus 13s or whatever that works out to). Hopefully you will still avoid fuel cut for the sake of getting a good log. If the timing looks better, start to go plus or minus a couple percent and see what works best. I hate to go by O2s, but on a 2g .90 is almost always too lean for pump gas. HArd to say though. On a 1g, that would be right on (They seem more repeatable). The timing substantiates the suspicion that it migh be too lean.

If possible get me a log with airflow added. With that I can calculate airflow per revolution and estimate what timing should be if there was no knock.

There is no need to go over 7000, but go at least that far. Timing is "all in" by then, and thats all I need.

Looks like some good progress none the less. Good sample rate, up to 7000 rpm, and no fuel cut. We'll get it there ;)

Here are 3 logs with the following SAFC-II corrections:

This is with a -11% correction on the Hi-throttle tables:

http://files.automotiveforums.com/gallery/watermark.php?file=/503/155962SAFC-II_Correction_-11_.JPG

This is with a -13% correction on the Hi-throttle tables:

http://files.automotiveforums.com/gallery/watermark.php?file=/503/155962SAFC-II_Correction_-13_.JPG

This is with a -15% correction on the Hi-throttle tables:

http://files.automotiveforums.com/gallery/watermark.php?file=/503/155962SAFC-II_Correction_-15_.JPG

Shouldn't he be able to turn up the boost on that 16g?? Or should we wait until we get a good tune? The pull at -11% looks decent, but the timing advance just isn't there. By the way, what calculation are you using to get timing advance assuming no knock?

Thanks again!!!!!

those look a lot better, tune it the way it is now so you get a handle for it then slowly turn up the boost and add more fuel until you are at were you want it!

I don't understand why the timing is so low. If the boost goes up, the timing might go down more.

yeah, wow, thats just really low timing, do you know what your base fuel pressure and timing is set at?

SOmething isnt right. The LOWEST timing maps in the 2g ECU (used over 2.1 grams/rev airflow) peak at 16 degrees between 6 and 7k rpm. It doesnt get over 10 until around 5k. He is not getting over 2.1 g/rev so timing will be even higher. Use airflow in lbs/min divided by rpm (pounds per rev), then convert to grams (multiply by 453.5924).

The ECU doesnt know what other things are set at like FP, base timing, etc, the only imputs it factors into the timing result is intake temp (over 84 and under ~35 degrees F it pulls 1 degree) and coolant temp (over 206 it pulls a degree, over 220 or so itpulls 2).

I'm assuming this has to be knock. On a 2g you arent supposed to be able to set base timing, but put a timing light on it anyway. Thats the first thing I would do. The next thing I would try is raising the octane, run the tank real low and add a gallon or two of the highest octane race gas you can find, 116 or 117 perfereably. Or xylene/toulene additive if you are comfortable putting paint store chemicals in your tank (plenty of info on the internet, I've never tried it personaly, but friends have used it sucessfully). Pain in the ass, but we have to start the process of elimination ;)