Zr1 wot tuning issue

[J2Motorsports]

Tuning a customers 2010 zr1 with upper pulley, lower pulley, lt's, fic 1000cc injectors. Car runs very well afr's are 10.9-11.0 on 93 but for some reason wot at around 4k rpm the car starts dropping injector msec. It also shows it in the power it makes but not in afr which doesn't make any sense at all. From the previous tune I had with just lt's it has lost 15hp but gained 80+tq.

[Cruze]

Can you log fuel pressure?

[gmtech16450yz]

Looks like the MAF calibration to me. You go super rich around 7khz, then super lean around 9khz. Look at this screen shot, it's comparing your maf cal to a stock ZR1 calibration. I don't think anything you could have done to the intake could have made the maf cal curve vary that far from stock. From the looks of the narrowbands, it does look like it's going leaner, it's not just the injector pulse, it is actually leaning out, at least from where it was before the pulsewidth drop. The narrowbands actually look really rich, what are you using for a wideband? Is it accurate?

Try it with the maf calibration closer to the stock curve and see what happens. I think it's running richer than you think, which would explain the higher torque and lower hp. Just my guess though.

[gmtech16450yz]

Here's your o2 reading, as you can see it is dropping, but it's also super high. .80 Lambda should give you AROUND .900 to .925 or so, which is ballpark where you should be at on an LS9. You're at .960-.980. That's too rich. Lean it out and fix the maf curve and I bet your power comes back.

(BTW, let's not start a "Don't EVER use narrowbands for tuning" sh!tstorm here guys. lol. I don't have a wideband reading from his log. The narrowbands are ALL I have to go by.)

Here's your narrowband trace zoomed in at a min of .95 and a max of .98.

[J2Motorsports]

I'm using the innovate lm2. It's always been pretty accurate from what I've seen. From the stock settings, the car is way to lean in the maf table not even comfortable to make a wot pull it's so lean. The maf cal varies so far from it because of the pulley setup. It now has 3-5 more pounds of boost an definitely comes on a lot quicker than stock. If I lower the table any around the 7k mark, the car goes lean when you stab the throttle from 2k. I've made probably 4-5 wot pulls on the dyno with this tune today, so I would think that if it was dangerous lean around 9k it would have already hurt the motor.

[SultanHassanMasTuning]

could be a miss as well

[J2Motorsports]

It doesn't show any miss in the log that I have seen.

[GHuggins]

First off - get rid of that pos wideband Seriously get an AEM 30-0333 - fraction of the price and as close to the accuracy of a very pricey unit as your going to get... I've never once had a LM2 that reported corrected...

As GMTech pointed out - your MAF is way off - it's adding anywhere from 10 to 25 percent in the lower throttle areas and overly rich in the higher rpms... Your timing is most likely the reason for your low power - bet you could add a degree or two and do better right from the get go - these things are really sensitive on the knock parameters... These engines are stout - they can take a few pulls being lean... I didn't see it leaning out up top according to the O2's though?

Target 11.8 when you get a good wideband

[gmtech16450yz]

I'm using the innovate lm2. It's always been pretty accurate from what I've seen. From the stock settings, the car is way to lean in the maf table not even comfortable to make a wot pull it's so lean. The maf cal varies so far from it because of the pulley setup. It now has 3-5 more pounds of boost an definitely comes on a lot quicker than stock. If I lower the table any around the 7k mark, the car goes lean when you stab the throttle from 2k. I've made probably 4-5 wot pulls on the dyno with this tune today, so I would think that if it was dangerous lean around 9k it would have already hurt the motor.

I didn't say it was dangerously lean or even lean, it's actually pig rich. Your wideband is wrong, the narrowband readings are telling me that. You could have o2 readings in the .800's and you're not going to blow an engine from being too lean. You're in the high .9's. And simply raising boost pressure should NOT make the maf curve itself that far off.

You have two guys telling you that it's too rich and your wideband HAS to be giving you false information. That's where your power went. High torque and low hp is also telling you that the engine isn't happy and isn't getting the fueling or spark it needs.

[J2Motorsports]

Ive compared the lm2 to the aem and it reads pretty dang close to the same. Ive been threw 4 different widebands. An if the car was extremely rich down low, then it wouldn't have picked up the power that it has. It has gained over 50hp from 2k to 4-4500. The top end, where you say it goes lean is where I have lost the power. Ive went up and down with the timing, anything over what I have in it now will cause it to knock and pull timing. So 11.8 is safe on 93 with these factory boosted cars with 15-16lbs of boost?

[GHuggins]

It's not rich down low. It's lean. Look at your fuel trims. If torque is high then timing is close in that area. Timing and tq almost always correspond to one another. Fueling is a little different. You might just find leaning it out a touch will require different timing, but be better all the way around.