MY ECUtalk has thrown the following max Values in a drive yesterday: INJ: 99/99% TPS: 4.06V AFM: 5.115V Timing: 45° BTDC / -5° ATDC There are some underlying issues which I am not sure whether they result from the current setup, or if there is something lacking in the build. From this, I want to find out is where the best performance gains can be had given this information, or what info I need to get to know where to improve - no use throwing money at mods which are not needed (yet). What I have is a basic street build, nothing too crazy, and moderate power (300kW is ample and within the spec of the build). I have ECUtalk which is always on, I also have nistune / Datascan which I can interrogate other variables if they are needed. I have had a few cutouts on boost, which may have been AFM interference from the vented nose panel / wet filters from the car wash just minutes before. This may also explain the max'd out AFM voltage? The basic specs on my vehicle are as follows: Healthy engine, stock spec rebuild of bottom end and heads about 15-20K Km ago. Nistune, standard tune. 2.5 inch exhaust, highflow cats, high flow turbos, split dumps. Border airbox, twin K&N filters plazmaman FMIC, GFB BOVs Standard injectors, standard fuel pressure Boost approx 13 psi, eBoost2 EBC. From what I gather, I'm reaching max injector duty cycle at this boost. Is it best to up the pressure on standard injectors or go something bigger? I have not yet got the wideband O2 sensor fitted, but I have had continuous issues with killing cat convertors. Whether this is a result of having insufficent fuel on boost, I do not know. I can get the stock O2 sensor voltage out of nistune / datascan if needed. So what does everyone think about this? What should be my next step with this vehicle?
Def need bigger injectors. Increasing fuel pressure will not be enough. I'd also get a wideband O2 sensor & guage asap. IMO this should be the first mod before increasing boost or any engine performance upgrades, especially on a turbo car.
I'm a bit surprised you are maxing out the afm at 13psi of boost. Looks like you will need bigger injectors.
I suspected the injectors were running out at the higher limits. Good info Eric and chrispy, but I believe any residual water on the filters may have skewed the voltage on the MAF, it was cutting out on boost. Water would cool the hot wire to make the engine think that it was sucking more air, and as such richen up the tune, and lead to stumbling? I'll have to do a dry run to see how she runs. I'll attempt to get some maps of the AFM signal to see how it travels, or at least another max value on the ECU talk after a 3rd gear pull.
What's your fuel pump like? Original? I know Kieren had some weird issues with duty cycle that were fixed with a new pump. No idea how, and I still don't completely believe it But Eric promises me that's what was changed
Original pump and FPCU. Is what I'm seeing, given the data, normal for this boost level? I think I need more testing. I'm looking at a max value, without reference to other variables. This may be a spike at a result of the cut-out on boost, not a true representation of what is happening. When it's dry out, and I get the computer hooked up, I'll get a data log graph up for us to look at.
I was getting similar AFM levels with HKS2510's ported heads and big cams at same boost level. Big injectors, and can't remember the duty cycle.
I'm surprised that the injectors are maxing out at 13psi? Are you confident that your getting accurate reading from your boost gauge Mitch?
lol , I never checked the rpm readout was just watching the gauge and then quickly checked the Inj duty . But I feel stock injectors are no good for anything over 12psi imo .
Anti's car at 16psi wasnt maxing the injectors and neither is my cousins at ~13-14psi. Have your fuel system looked at, you may have an FPR problem. Mitch i get a similar problem in the NA, cold night and a hard run to redline will see 99% IDC fairly easily, especially if i hit the rev limiter.
That looks maxed to me , I thought 99% was maxed . I have an AFM FPR might put that on and see what happens .
Have you configured ecutalk to the correct settings? cyl count etc? How come your TPS voltage is so low? Pull the accel stopper out and try foot to the floor. And check idle TPS voltage. Expect to see it up near 5v.
Quick-and-dirty graph time! I logged and graphed AFM voltage and injector duty cycle on the Y-axis, vs chronological RPM over the course of a 3rd gear pull Peak RPM was 5388 RPM (Scale is a bit out of whack) Peak boost was 12.5psi Max AFM was 4.62V Max injector duty cycle was 89.08% with a peak TPS voltage of 4.06V (I need to adjust the TPS as it's voltage is a bit low idle) So on a 3rd gear pull it's not using all the injector duty cycle, but pretty much on the limit of the stockers. AFM has some headroom. RPM still has a fair way to go to redline. Run 2 was as follows: 2nd gear pull AFM Max 4.73V Peak Boost 12.1 PSI Max injector duty 106.48% (Not sure how datascan calculates this as >100%) Max RPM 6162 TPS Max 4.04V So looks like I'm hitting the limit of the injectors in 2nd gear. Engine load should be less due to gearing, so not sure why I'm showing such high duty cycle at this RPM? Just looking at the data with a few quick calculations, this duty cycle should be seen closer to 6,400 RPM (if duty cycle is linear with RPM?). Run 3 was as follows: 3rd gear pull AFM Max 4.72V Peak Boost 12.2 PSI Max injector duty 97.36% Max RPM 5888 TPS Max 4.72V Does anyone have any further interpretation of this data, or know what variables would be best to graph to make better sense of all this?
Yeah. l know this will help with the K-value for the new injectors at a later date, but Nistnne will not really help already maxed out injectors perform better? id probably get better data out of Nistune -engine load and AFR's for epample.
