All you guys are over thinking it.

What is a ported MAF fundamentally?

A larger hole for airflow (if needed) Usually at high rpm.

GM added a larger MAF to the 01 so there is merit.

GM removed the screen in 02 LS6 so there is merit there too.

What are by products of ported MAF? Timing advance due to getting more air in unmetered and hence giving the PCM a perceived smaller load.

Does the MAFT translator assist is tuning? Hell yes it does.

Do those that give up on the MAFT give up to soon? Yes they do.

The PCM does not "learn out" your maf settings on base and especailly WOT.

Yes the O2 sensors will always, no matter, what adjust your closed loop mode to 14.7 stociometric. Unless it hits a predetermined limit of about +/- 25% (then a code is set). What you end up effecting when you tune base with the MAFT is where the perceived engine load is at.

On WOT, the engine soley relies on the MAF, RPM, and TPS input to perform fuel delivery to the injectors. WOT settings are combined with BASE setting on the MAFT at high frequency to allow fine tuning of WOT. The PCM freezes fuel trims and any other PCM updates under WOT. O2 sensors are completely ignored. Thus any WOT changes are direct and permanent. And do not require PCM "learning".

Beleive what you want but this is exactly what happens. There is no hocus pocus or magic occuring. Its really simple to understand it you break it down.

If you would like more in depth understanding of the control system.

see:
http://www.vetteguru.com/mods/howto




[Modified by kewlbrz, 10:37 AM 8/14/2001]

 

Oh hell... Just when I thought I was doing good, we end up with this MAFT discussion again! I'd be interested in seeing some real-world, scientific data on the subject myself. kewlbrz' explination seems to make the most sense, though. I just don't understand how people are ending up with LESS power after the changes... Doesn't make sense. :confused:

 

There is not a single soul here who ended up with less power using a properly tuned LS1 with Ported MAF, MAFT and Autotap.

Anyone who got less and gave up, never did it right to begin with.
Come on you all know who you are. Fess up.

I did it verbatim per Kewlbrz,Team ZR-1, and Mellow Yellow. It works Period end of story.

I am giving up on trying to convince you guys cause I'd rather you quit. Then when I see you at a light I have a better chance of winning. :blueangel:


[Modified by chuckster, 2:45 PM 8/14/2001]

 

WELL, I'm a convert. Put the Breathless MAF ends with airfoils back on after getting my Auto Tap and MAFT. Had to go plus 10% on the LTrims and got those to read out at 0 to -05. I drove the car for about 100 miles and Atapped again and the 02's were right at .890 at WOT. I had Ed Wright programming after the 3.42 gear installation but nothing else after the MTI B1 cam and LS6 intake install. It dyno'd at 349 HP right off the rack but I'd be willing to bet there is another 10Hp or more there now. At high RPM's it just wants to keep pullin and pulling and I have the limiter set at 6700. Plan on driving another 100 miles or so and then tap again. So far I'm converted. We'll see.

See ya :seeya
Easy

 

Welcome to the Club Easy!!! :cool:
:cheers:

 

Hell, 'Net that's where I bought my beast. Best price in the U.S.! Anyway, I'll bring my GMS MAF 5%, and a few bucks for the runs-but I'd prefer not to be the test mule (though wouldn't mind one run for my own baseline with the mods). Let me know at Davep17@hotmail.com., or here at the forum :D

 

Unless you guys plan on driving a ton (up to 250 miles) then autotapping between runs to ensure long term fuel trims have been fully updated, and strims are at or near 0, the tests will be completey invalid.

 

Kewl, are you telling me, that back to back tests of the stock '01 MAF, stock '01 MAF with the screen removed, and GMS 5% MAF will be a useless test?

I guess I'm more concerned with "bolt on" stuff-not the fine tuning for that extra few horses with the autotap.

If someone sells a bolt on and makes claims here on the forum, I expect it to deliver-even if just "half" the claimed hp! I know that a larger MAF may result in a "slight" reduction in low end torque (intake velocity)-but if I lose 20 lbs of toque until 4000 only to gain 5 hp at 5500-I've lost in the grand scheme of things. Here I am willing to drive 500 miles round trip to get a straight answer...I've spent a lot of money, time, and UPS waits with Granatelli-and I think we ALL deserve the truth here.

This is not a Vortex vs. MTI, vor !@#$ing exhaust plate-we all know they deliever more power (big question is price, looks, and who makes a few hps more...).

Why can't we get straight answers on this? If the GMS MAF is a flop, we need to know. MAYBE HE NEEDS TO KNOW! :mad

 

DAP, I sympathize with your frustrations. But I think you are not understanding the concept of all these mods. GMS, MAF ends, whatever. And how the PCM reacts to them. This isnt rocket science. The PCM is 100% is programmed to do only certain things.

Im all for comparing mods on the dyno and track. I really encourage you to read my write up on what is really going on with the system. If you understand the system, you will totally see that back to back dyno runs of changing MAFs out is a complete and utter waste of time without allowing the PCM to fully normalize between swapouts. And by that, that means the PCM must fully update the long term fuel trims, and reset the strims. A lot of driving, and an OBD-II scanner would be your only option for that. Nobody said fooling with the PCM easy. Its a long term process to dial everything in.

Sorry if this upsets your plans, that is not my intention. I am actually trying to save you effort, and/or at least what it takes to qualify your results.

 

Sorry dude, it is just gettin refriggindiculous :crazy:

Liked your article.

But I'm still a little confuse, so I'll just ask you flat out, is my GMS MAF 5%, a worthwhile mod on my '01 (I have a Vortex ram, LAPD high flow duct & coupler, TB bypass?)

I am planning on some Hyp/Sup/Pow cpu change, 172 thermo, and long tubes (dumping the pre-cats) in the near future. Doe GMS's hardwired MAF 5% help remove the chance of short and long term lean conditions?

 

Id say the gains/bennefits would be hard to measure when comparing a GMS MAF to a Stock 01 MAF with its screen removed.

Remember the 01 computer is allready calibrated to accomodate the larger MAF housing.

The 5% GMS would be nothing more in my mind, than a compensation for not having a screen in there to assist in some laminar airflow. Other than that i see no difference.

So in essense you could equally have a stock 01 MAF with the screen removed, and use a MAF Translator to dial in your WOT.

The 5% rich GMS MAF would be 5% across the board as I understand it.

It could be a little less or more on low frequencies, and be 5% on high frequency.

No different than what you could do with PCM programming or a MAFT.

If I had an 01 I would not focus on the MAF with stock displacement motor. Probably would just remove the screen.

 

What about the MAX FLOW MAF?? How does this unit compare? :boxing


[Modified by jschell, 11:53 AM 8/15/2001]