Getting close to finishing my build. Its a stock 1999 5.3 LS from a silverado. Swapped to an Fbody oil pan, blue LS6 valve springs. I'm working on the OEM harness to work as a standalone for my 87 firebird.

I hear conflicting info about using a MAF for forced induction. My plan was to delete the MAF and I added a new IAT sensor in the EGR block off plate. Ive upgraded to a 2 bar MAP sensor and I have HPT pro. I'm still in the process of cutting and shortening but I did cut out the MAF already. I can easily splice it back in. Ive got a torqstorm supercharger installed with the smallest pulley and I should see 10-12psi on the stock 5.3 (prob more like 10-11psi). As well as 72lb Bosch injectors from FIC. This car will be mainly street driven as a fun car in only warm weather. Since the motor is basically all stock minus the supercharger I would love to make my life easier for tuning as well as driveability.

So whats the consensus? Is the MAF ok for this? or should I just say screw it and use a 2 bar operating system? I dont want to have to change the OP system and waste the credits. So if its too close to work then recomend the best/safest option.

Also can the MAF be mounted at the SC fresh air inlet vs in the charge pipe?

Lastly when converting from MAF to SD how and what tables need to be converted? i used to tune alittle in the 87 TPI ECMs back in the day with Moates stuff but this is a whole new level.

 

Go speed density. After daily driving 2 different vehicles with it I see no reason to mess with it on a boosted warm weather only car. Neither one of my vehicles had problems at all from it

 

I can't say with 100% confidence but don't think you can run the 2 bar MAP with the MAF, or at least make it worthwhile with referring to the VE table. HPT in the 2 bar os forces you into speed density.

I haven't tuned as many as others out there maybe, but I would say ditch the MAF and stick with the SD. If it were a newer ECM with the card style MAF that seem to be more accurate and responsive, I would say do the MAF and dial in the VE table.

I've tried to play with cars on a MAF and it seems that you either running out of fuel during a pull or going lean during a pull because at a certain point in boost you end up sitting on the last cell of the MAF table. You're really moving more air then it can read and to my knowledge (again little research honestly done on my part) you can't compensate for it really.

I did my wife's car cam only SD and compared with the MAF tune dialed in and she liked the SD tune better, could even tell the difference in response and said she liked how it seemed like the car was the same day to day. This is something pretty much driven daily during the summer, rain or shine. Just went straight to building on top of the SD tune when we did the turbo on the car for her.

My brother's 04 Z runs the MAF and I dialed the car in with the SD tune. Just pulled the car out of hibernation and asked me if I could throw on the SD tune for him because his memory is the same as my wife, faster throttle response.

My G8 I have the LSA on I have the MAF with the dialed in VE and a card style maf and it feels like it is as responsive as the SD cars. Before the card MAF I could feel the hesitation like with the TA before the SD and like in my brothers car.

Anyway, sorry for long rant, I would stick with SD and ditch the MAF.

 

**** a maf

 

Thanks for the responses.

So SD gives better throttle response but MAF would handle larger changes in ambient temps. Only reason I say that is because in the spring/fall I might drive the car in 70* weather, then drive in the summer at 90-100*F when car shows are going on... thats quite of range in temp for a SD tune to work in no? I just know that MAF's are more forgiving and SD can be a picky bitch.

Lol Blown06... tell me how you really feel.

 

I don't see any wild swings in fueling vs temp changes in SD.
Maybe 2% which doesn't affect anything.

I also run it in closed loop with only the short term trims on. I do that after dialing in the VE with the wideband.

 

So then I guess speed density it is lol. If I were to go back to MAF or run MAF I have the OEM MAP sensor I could still use. I just got a cheap $15 2 bar MAP sensor off fleebay for the SD tune.

Man I gotta really buckle down and start learning to tune again lol. Closed loop def for me as I will be spending most my time below 3500 rpms on the street, short term trims? Sounds like small adjustments to A/F allowed to be made to the base VE table?

what tables do I need to "change" to convert the original MAF tune to the 2 bar SD tune? bear with me guys lol consider me a newb.

What I would like to do is swap everything from the MAF tune to the SD tune, I know I'll have to convert some stuff like the MAF gm/sec to whatever table in the SD tune (haha).

Then its just simple changes:
unlock ECM
disable VATS
cooling fan temps (converted AC wire for fan high speed duty in ECM plug I think)
disable trans control functions (2004R so no computer controls)
Set injector flow rates and sizing
Tune for VE,MAP and IAT tables
Set idle speed.

 

This is not true. On a MAF setup, it operates in SD mode during times when you stomp on it. So they would be the same.

 

why you gotta go and say that lol.

But its safe to say its possible to max out the MAF before WOT right? Also couldnt the MAF be mounted to the inlet to the supercharger? so its sucking air through it? but it would be sucking alot more than it normall would as the supercharger is sucking alot more to be able to compress it as the motor is still ingesting it. This for sure would max out the MAF and scaling the values would kill the resolution correct?

 

I'm running a 4" intake with a card style MAF. I haven't maxed the MAF yet after recalibrating, but will most likely switch over to SD when the time arrives. For now, there's moderate scaling, etc that i can do.

 

Yeah the LS1 MAFs will max out fairly quick. The Card style MAFs like LS3 or LS7 or much better. And it doesn't matter to much if you put it pre or post air charger, but if it were me I would prefer post.

 

Seems like people with MAF plan to go SD. Guess I might has well make the switch now.

Not buying a new MAF or anything. Just going to use what I got which is the OEM Delphi truck MAF or just jumping to SD.

 

The card style MAF can handle a lot of power and when tuned right runs great. I have been running MAF only for years and the car couldn't run better.

This spring I am going to try a blended MAF/VE tune just for something to play with but I have no real need to.

 

Haven't heard anyone mention scaling the tune so you don't max out the MAF. I had my tune scaled 65% with an LS7 MAF in a 4" tube with a honeycomb installed and it drove great day to day and didn't max out the MAF.

 

Yea I know the Card style MAFs are better... but I dont have one and I'm not going to buy one and then figure out how to mount it on my short run of charge tube lol. Its either Stock Truck MAF or I'm just going SD.

I tuned my TPI like 6 years back with a grannelli high flow MAF and never had any issues but that was maybe 375whp 383 and It was NA.

 

When you scale you loose resolution and the MAF becomes less accurate. Sure it would run great by why desensitize a sensor that is designed to be sensitive lol. Scaling would be a great bandaid if there wasn't better options out there and you didnt have a choice. Same thing would be like running a 3 bar MAP sensor in a 2 bar OP system and running low boost. Now if the government said I had to keep my MAF setup since the original setup was MAF for it to be driven on the street then I would pick up a slot MAF and scale lol. But Adding it in now would mean I would have to cutup what was made and add a few possible leak points. Or run it before the SC and hope its not maxed from the increased sucking of the SC.

Heres a pic of my setup thus far... no room in the short 15" charge pipe lol.

 

In the grand scheme of all the sensors and rounding in the tables and injector timing, I do not believe the loss of resolution matters, especially for a rather linear and stable condition like WOT. Transient tuning yes I agree you do lose resolution that could have an impact, but not at WOT. I had my scaled MAF only tune within 1% of commanded AFR at WOT so Id say its accurate enough.

 

On a 99 vette we just did at the shop. Procharger P1 doing 11psi, headers, full exhaust.

It was tuned SD but the MAF was left in because we didn't have the correct piping/coupler to delete it at the time it went on the dyno. I removed the MAF and put in a straight pipe and picked up about 30rwhp with no other changes. Car made 555 to the wheels.

 

I don't see the scaling as a big issue, but looking at your picture, a MAF is not even an option. You have room for one but that BOV would totally wreak havoc on it.
Go SD.... it works fine.

Beautiful looking engine bay by the way.

To add.. looking at the pic again you actually have a great straight piece of pipe for a car style MAF... and welding a bung on is easy..... but again... wont work with BOV there.

 

Wow the MAF was that big of a restriction!?