chuckster

I keep hearing people say that they went back to the stock MAF (no screen) and their car pulled like an animal. I kinda felt that the MAFT/Breathless Ends with Air FOil did the same for me... But hey I'll try it if it works......

I think I will go back to stock before I start my LS1-Edit Tuning.
any opinions?

Stu in CA

That's what I was told by "my tuner," so that's what I did. Ditched the Vortex for a BW also. I never liked the way the "Air Foils" wiggled when installed anyway, nor the fact that two holes were misaligned and had to be redrilled and half the holes were countersunk on the INSIDE and the stock screws did not work and ... manufacturer said they would have to see it to comment (on the inside countersinking, etc.) no thanks

6Speeder

I'd leave the aftermarket ends on. JThe only downside to them is that they change (increase) the air flow so the calibration needs to be changed to match the flow. But that is what LS1 Edit allows you to do. Go with the additional flow and tune for it.
IMHO tuners hate MAF ends because they have developed their tuning around stock ends and don't want to take the time (read $) to accomodate the change. Yes, it is a pain to recalibrate the MAF properly, we're on custom program #7 for my car, but that's also part of the fun of modding.

66ImpalaLT1

I would put your stock ends back in. Maf ends are not a restriction. They cause a car to gain power because the mis-calibration causes a lean condition.

The only upgrade I will do to my MAF will be an 02 z06 maf, and then I'd put in the 02 z06 maf table.

Eric

Stu in CA

This is what I've been shown (with EASE traces, calculations, and the tuner's ET's, etc.), along with the homely stock intake duct and the "accordion" coupler, neither are the next restriction in the stream.

Like bolting a ported and/or larger TB onto our intakes, not necessary.

Good thing about removing the nylon one's is that you can sell them!

TLewis4095

I took my Breathless MAF ends off prior to tuning so I don't know the answer...I did jump from 317rwhp to 337.7 when we were done on the dyno! It took 6 runs, and the A/F of 12.2-12.3 seemed to produce the most HP for us. If anyone wants the BPP ends w/foil I'll sell mine for $100. :cheers: Final#'s after LS1 edit tuneing with the mods listed below: 337.7 rwhp, 342.5 rwtq. I'm a happy camper! :D :cheers:

akw408

Since you'll be remapping the MAF table anyway, I'd just keep the ported ones on there. I did.

chuckster

Ok, nobody has given me a concrete answer why to go back to stock. Let's assume the MAF is calibrated perfectly with LS1-Edit...Why not keep the MAF ends? They are nylon so no heat soak...I can only think of all positive things...

ToplessTexan

So how do you plan to do this?

chuckster

I know this is a loaded question so you tell me.

akw408

I did it by recording down my LTFT, MAF frequency, and air flow using a scantool. Drove around for over an hour, under all types of driving conditions. Then you take the air flow, adjust it using the LTFT values you recorded (if it's +5, you multiply the air flow by 1.05) and then plot the air flow vs MAF frequency. Do a best curve fit using some plotting software and then input that curve into LS1 Edit. It took me about 3 iterations and now my curves are pretty much overlayed.

Or you can just take the average LTFT # and multiply the entire MAF curve by some factor using the average LTFT, but I didn't think that was precise enough.

ToplessTexan

I'm thinking a bench is both easier and more accurate. I shouldn't need to have the sensor anywhere near a car to cal it. ;) It's great if you got good results, really, but I would have a hard time calling that a cal.

akw408

Yeah, it's not the cleanest calibration system, but it's the results that matter. :cheers:

ToplessTexan

I will say that relying on LTFT, a vector with rather large variation among elements, as an indirect variable is only valid if you believe that the dominant source of variation in it is due to the MAF signal.

I'm still not clear how Charlie was planning on doing this.

I guess I am looking to clarify what people mean when they say use the term 'calibrate.' In my case I mean either a) adjusting or b) interpreting a sensor's signal such that it accuately and reproducibly respresents the measured quantity, in this case air flow. As soon as we start talking about fuel trims I think we've stopped talking about calibrating the MAF sensor.

The only reason I care about a faithful MAF signal (and the reason most tuners are quite happy with a stock sensor) is that everything under the sun in the PCM code seems to use calculated load as an independent variable. Manipulating the underlying signal in response to only one of the dependent variables is likely to have undesireable, unanticipated, and/or unknown effect on other dependent variables.



[Modified by ToplessTexan, 7:13 AM 9/24/2002]

chuckster

Kurt, you may have a great point here...Part of the problem I see here is this...The Stock MAF obviously generates a higher velocity. This in turn may actually help fill those pesky cylinders in the rear.

So far I have heard put the "stock back on" and "leave the ported ends on"

But...Nobody here has actually said they have seen an increase in performance using the Ported ends (recalibrated by whatever means) Most of the positive posts come from going back to stock...

Boy, If I get $100 for my ported ends and $125 for my MAFT...my LS1-Edit only cost me $325 ;)

So in short...I think that I will put the stock ends back on for the Velocity gain alone...I will start my tuning from there...

Hmm did I actually make a decision here? :D

Stu in CA

Yup, sounds like you did. That was my decision. My tuner said no gains to be had from the ends, but I did recoup $100! :lol:

akw408

You know, I would agree with you 100% if everything else in the car was calibrated with the precision that you're expecting, or if it really mattered. Once you throw in 30# SVO injectors, the entire system is already off anyway. I doubt that the system was precisely calibrated from the factory. The way I see it, basically the point of getting the MAF curve as close as possible is for open loop operation, under WOT. At partial throttle, you don't have to be very precise since there's a closed loop fb system. You have two major parameters to play with at WOT though, the MAF curve and the PEvsRPM curve.

akw408

I wouldn't be so sure that the stock MAF has a higher velocity, that screen probably has something to do with that.

And I'm not convinced higher velocity really matters before the intake manifold. If it did, why do huge honking intake filters and ported throttle bodies help?

chuckster

Actually The mere physics of it tell you that the velocity does increase. Let's use idle for the example...Since the same volume of air is going through the engine at 750 rpms that is our reference point. Lets say the air going through the stock maf is traveling at X. If you made the MAF 2 times the size then the velocity would be significantly less.

And since the air has a direct shot straight into the intake plenum then it stands to reason that the velocity may help get to those rear cylinders...

I may polish my MAF Ends in the meantime... Man that sounded dirty...:D :lol:

akw408

Wow, this is getting really off topic here. I don't want to get really into it since I'm not a physicist and haven't touched physics for about 8 years, but I think you're confusing volume of air with just the simple opening area of a duct. There's also another factor that you haven't mentioned, pressure. If pressure is kept the same, the larger duct will carry more volume of air, the smaller duct will carry less air, but velocity is still the same. Now if the pressure forcing the air or pulling the air through the smaller duct is greater, then the velocity will go up. So in terms of simple physics, you're wrong, but in terms of cars, maybe you're right. I don't know if the intake manifold vacuum pressure will increase with smaller MAF ends. I'm sure outside atmospheric pressure will remain the same though.

Anyway, this is not worth getting into a huge debate over. Fact is you will probably not notice any SOTP difference. :cheers: