MAF questions, mismatch of parts

[mkehler]

Hi all, new guy here. Almost done my 1970 c10/lq4 swap. PCM wise using a 2002 5.3 411PCM all I have done is turn off VATs. With respect to MAF, I have looked at some 4.8, 5.3 and 6.0 repository stock tune MAF curves and settings and they are not consistent values. I believe all 99-07 truck maf's are the same, ACDelco p/n 213-4160. So - how should I baseline the MAF config in my tune?

MAF and factory airbox - from 2001 4.8 liter truck.
PCM - from 2002 5.3 liter truck
Engine - 2001 LQ4 (from...something)

thanks!

[dermotw]

MAF might be the same... but the airflow isn't (nor will yours be, if any part of the air path is different, although it may not be much of a change). So, (perhaps someone with more experience will add better info) imho, choose the one from a vehicle closest to whatever you have in the way of engine/air path/air cleaner arrangements, and start from there...

[mkehler]

Thanks for the reply. I'm actually using the factory intake tube as well as factory airbox from the 4.8. i don't have a 'duct' from behind the grill/fender to the airbox inlet as the original 2001 truck did but the intake tube and airbox are the same. So - unless there is a reason not to I'll just use the factory 2001 4.8 values to start. good idea?

[dermotw]

LQ4 is a 6.0 I believe, I'd use the MAF curve from a 6.0, it'll be closest I'd <guess>. Just copy the maf values across.. you should change a few other things too, if the base file was from a 4.8, because the cylinder capacity will be wrong. Myself, I'd use a base file from an engine that was similar in capacity to the actual one you have now. You could indeed start with your 'old' file and start altering things, but you might end up altering a lot, lol. I went from Ls1 5.7 > LS376 6.2 with 'old' ECU/file as a start point, & I have lost count of how many things needed a 'tweak' to get right. Injectors are probably different in yours, MAF, idle setup, throttle I guess...

Maybe someone who knows that swap can chime in with more useful help!

[IARLLC]

I would agree about using almost all of the data from an LQ4 file. One thing I should mention as the computer is from a 2002 5.3...there were a lot of "flex fuel" 5.3s in that era. The flex fuel trucks used larger 33lb/hr injectors while the rest of the trucks all used the smaller 24.8lb/h injectors. If the computer thinks that your injectors are MUCH larger than they are....there will be confusion. Under fuel>general>flowrate you should check if your 5.3 tune has 33 or 24.8. So if you are using the 6.0 injectors you can just copy everything over from an LQ4 tune.

[mkehler]

thanks, didn't know that about the 2002 injectors. will baseline with all the lq4/6.0 config and hopefully on the road for this weekend. Thinking about getting a couple AEM wb's permanently installed to help road tune but we'll see how this weekend goes

[IARLLC]

Yeah, I don't know what year Chevy started offering the flex fuel option but their injectors are even bigger than the ones offered in 8.1s.

[355LT1]

I was just there on an LQ4 transplant. The whole CAI configuration was completely different than a stock 06 Silverado. I ended up having to seriously jack with the MAF table. The stock table was overstating air flow by at least 25% in the upper ranges and I was piggy rich. You can plan on re-mapping the MAF curve for sure. I originally thought the stock curve would be pretty close. WRONG

BTW : you may want to look at the PE enable settings. Many trucks had no PE from the factory tune. They just ran'm lean as Heck at WOT.

Regards,
Steve