3.75L Build thread

[AdamVR4]

I know how to pressure test the charge pipes... Post maf is what I was saying... The intake plenum half.

Why would you ever bother pressure testing only half of the system? Why create more work for yourself to be half as productive? Just get the Z06 MAF out of there and your life will immediately be easier.

[AdamVR4]

The LS1 MAF should fit your pipes perfectly and not leak. Seriously, I wasted so many hours chasing my tail with the Z06 MAF leaking in blow through...

[Chris@Rvengeperformance]

pull some of the front plugs and see if they are sooted up. Swap new ones in and test again. Even one would be fine.

[Chris@Rvengeperformance]

I know that the ecu is richening my trims because at idle I am drawing in unmetered air. I have not found a good solution for this. I haven't started dumping fuel on idle yet because the car smells very rich at idle already.

The wideband is about (guesstimating here) 16 inches downstream from the narrowband

Ill try and play with the base knob. I want to pressure test first

100% of the time injector latencies posted by others won't work for you. The evo guy's method using low and med trims to get the scaling right works great.

Air leak or not you can easily tune it out by adding a little bit of latency.

[Greg E]

100% of the time injector latencies posted by others won't work for you. The evo guy's method using low and med trims to get the scaling right works great.

Air leak or not you can easily tune it out by adding a little bit of latency.

That tuning method works but its not the best approach as you're compensating airflow/VE changes with the latencies. The latiencies you see posted on the injector rehab site are results from actual injector testing. While its no big deal which one you change, the real variance is with your particular engine/setup and how it draws air. Changing the scaling/latencies effects things globally instead directly in the areas of airflow you need to tweak.

[Chris@Rvengeperformance]

That tuning method works but its not the best approach as you're compensating airflow/VE changes with the latencies. The latiencies you see posted on the injector rehab site are results from actual injector testing. While its no big deal which one you change, the real variance is with your particular engine/setup and how it draws air. Changing the scaling/latencies effects things globally instead directly in the areas of airflow you need to tweak.

The tested latencies do not account for any variation in the way our ecu injector drivers work compared to their testing equipment. It works better for me doing it this way because globally it is dialed in close to stock, idle, mid, wot. Tuning via airflow won't scale as well.

[futurevr4man]

Why would you ever bother pressure testing only half of the system? Why create more work for yourself to be half as productive? Just get the Z06 MAF out of there and your life will immediately be easier.

im not sure what you are trying to get at? i am going to pressure test through the maf all the way down to the turbo inlets (and cap the inlets). i ALSO want to pressure test to make sure my intake plenum is not leaking and at the same time test the vac lines that are running to it. there are 2 halves to the system. i dont know how much more clearly i can explain that.

pull some of the front plugs and see if they are sooted up. Swap new ones in and test again. Even one would be fine.

are you suspecting a misfire, or are you just wanting me to check and see if they are running rich?

100% of the time injector latencies posted by others won't work for you. The evo guy's method using low and med trims to get the scaling right works great.

Air leak or not you can easily tune it out by adding a little bit of latency.

i bought these injectors new and i used the latencies provided with them. they are correct. and as greg said, i dont want a global change.



i think a pressure test will help me a lot, i suspect i have a boost leak (or 15) and lets see how that helps. i will also recalibrate my wideband, and i have new NBo2 sensors ready as well. i will hold off on the NB's for now, but i have them in case i need them.

[Chris@Rvengeperformance]

im not sure what you are trying to get at? i am going to pressure test through the maf all the way down to the turbo inlets (and cap the inlets). i ALSO want to pressure test to make sure my intake plenum is not leaking and at the same time test the vac lines that are running to it. there are 2 halves to the system. i dont know how much more clearly i can explain that.



are you suspecting a misfire, or are you just wanting me to check and see if they are running rich?



i bought these injectors new and i used the latencies provided with them. they are correct. and as greg said, i dont want a global change.



i think a pressure test will help me a lot, i suspect i have a boost leak (or 15) and lets see how that helps. i will also recalibrate my wideband, and i have new NBo2 sensors ready as well. i will hold off on the NB's for now, but i have them in case i need them.

The injector latencies provided with your injectors are 99% likely to NOT be correct for your ECU. The same thing goes on in AEM world. To get the correct latency for your injectors you can either start with the injector manufacturers specs and experiment from there or send them to AEM to get tested.

The car shows it is running lean at idle and it has lean spikes while accelerating. I have no idea why you wouldn't want a global change. If you find it to rich in the top end it is easier to tune that out than to fix part throttle. I just wanted you to pull a plug to see if it is actually rich.

[Chris@Rvengeperformance]

I guarantee you could take a 100% stock 3/s car from air filter to tailpipe, put in a big set of injectors, use the injector companies latencies and they would be wrong.

[futurevr4man]

how am i supposed to know which way to adjust them? i guess since i have lean spots you are thinking i should increase the latencies? the car idles really well, other than the wideband reading full lean and it smells really rich. as far as how the car actually runs though, it runs very well.