Running a BT setup w/ a BOV and now a MAF - advice on functionality!

[Marcus_Aurelius]

while this thread is still recent i have a related question-i was thinking about relocating the dv to post ic, right before the tb. If im running w/m, when the tb slams shut when i get off the throttle, will the w/m traveling through the dv, or back into the comp of the turbo have any negative effects on those components? Running a 007 dv if it makes a difference.

Not really an issue as long as you are not overspraying. What's your method of controlling the water injection spray? Pressure based, MAF based, Injection pulse based or Hybrid?

Ideally, you'd want to strategically locate your nozzles either way before the bypass plumbing (post intercooler) or right after the bypass outlet (pre TB). I guess thinking about a good spot to do the cold side DV relocation makes it easier to find ideal nozzle placement. I'll see if I can find pictures of my old setup with cold side relocation and multiple pre-TB nozzles.

[turbo2.24.1990]

thanks, i forgot to mention i'll be injecting post and pre tb, so i'll just run the dv pre the 1st w/m injection pt. Things are starting to get crowded between the ic and tb now haha, i'll have to get creative.

[Marcus_Aurelius]

That's the idea! If you plan the whole thing as a system it's not that bad to find decent fitment...

[turbo2.24.1990]

oh and its completely pressure based as i am running a 3076

[DougLoBue]

AWD dyno results from this past weekend to show how much power a MAF adds to a setup:

Runs were done back to back. 30psi. 85' day.

[gdoggmoney]

AWD dyno results from this past weekend to show how much power a MAF adds to a setup:

Runs were done back to back. 30psi. 85' day.

Please elaborate further, details, Tune and whether MAF was truly disabled, or just unplugged on A MAF based tune, or MAF dumped into a mafless tune ( Tapp claims his mafless tunes are great if you stuff a maf on them and adhere to the vacuum leak precautions).

[DougLoBue]

Please elaborate further, details, Tune and whether MAF was truly disabled, or just unplugged on A MAF based tune, or MAF dumped into a mafless tune ( Tapp claims his mafless tunes are great if you stuff a maf on them and adhere to the vacuum leak precautions).

Running Maestro with wideband and using a modified AWP 1000cc MAF-less base file.

So it's a MAFless based tune that I'm still daily driving MAFless until I get rid of the BOV and go DV. During the dyno pull I plugged the MAF in for pull one. Pull two I unplugged it.

[TooLFan46n2]

G'dog all the maestro files are configured for a MAF now, unplugging sets mafless.

Running Maestro with wideband and using a modified AWP 1000cc MAF-less base file.

So it's a MAFless based tune that I'm still daily driving MAFless until I get rid of the BOV and go DV. During the dyno pull I plugged the MAF in for pull one. Pull two I unplugged it.

Those are great results. Do you have any logs comparing your MAF vs. MAFless tune? I'd be reall interested in looking over them if your willing to share.

I'm still skeptical of needing a DV with a MAF tune. Everything I have read indicates MAF is not used during throttle/shifting transitions. Bogging while getting back into boost seems indicitive off not having the tune calibrated properly. I understand its the proper way to do it, obviously there are gains to be had from recirculating; just saying I still don't think its required as I never had any problems on my mafless file. Nice work looking forward to seeing more results

[DougLoBue]

Not a problem- I'll share my logs tonight.

I can tell you that my car was completely un-driveable with the BOV & MAF connected, but I also run E85 and it prefers to be lean and knocks a lot when rich. The whole stalling when coming to a stop thing wasn't going to work for me either.

With the stiffer BOV spring and the MAF disconnected there is also a loss of drive-ability- there is a hesitation when getting on the throttle that wasn't there before. I'll be swapping springs out tonight until I get the DV setup.

[gdoggmoney]

Running Maestro with wideband and using a modified AWP 1000cc MAF-less base file.

So it's a MAFless based tune that I'm still daily driving MAFless until I get rid of the BOV and go DV. During the dyno pull I plugged the MAF in for pull one. Pull two I unplugged it.

I know it's expensive, not sure if you could do it or have a hookup, but it would be nice to see if you let it adapt a while and drove it mafless to see how down on power it was.


This has been a hunch of mine for a while, that a properly running MAF based car will make more power and drive smoother all over.

[18T_BT]

From the way Chris use to 'tune' the maf vs mafless files was essentially if you unplug it, it' becomes maf-less...I don't remember him having two different files. I still own on of his 1000cc tunes and never did run a maf on it as it ran great without a MAF for me...

[iTech]

From the way Chris use to 'tune' the maf vs mafless files was essentially if you unplug it, it' becomes maf-less...I don't remember him having two different files. I still own on of his 1000cc tunes and never did run a maf on it as it ran great without a MAF for me...

And they still are that way...however some of the older files where truly mafless and if you plugged a maf it it did some really odd things. Now they are all bi directional files....can use a maf or not...it's your choice.


I am still trying wrap my head around the point of the entire argument in this thread...

[18T_BT]

Not sure how old the files you are referencing, I have still his original 1000cc file he was selling to the masses like 3yrs ago soldered in not flashed

[gdoggmoney]

I'm going to venture out on a limb here and say to the claims of "it runs fine mafless and with a maf" shenanigans.

50+ AWHP is not running right, boost for boost no other changes.


This is a HUGE deal...... and obviously not "You can just go mafless if you want".

[DougLoBue]

We're talking Maestro flashes, not soldered in chips.

I'm going to venture out on a limb here and say to the claims of "it runs fine mafless and with a maf" shenanigans.

50+ AWHP is not running right, boost for boost no other changes.


This is a HUGE deal...... and obviously not "You can just go mafless if you want".

I chatted this over with a few friends. There is no way to plug in a figure into a default airflow table and it's the same for every setup. Different turbos, manifolds, air filters, intercooler piping configurations, throttle bodies, intake manifolds, heads and not even to mention the crazy cams you can now put in them...

Also even if I was to populate the tables with the correct figures- when I change boost pressures the figures would have to change. When the air is more humid or hot/cold the figures change.

When you think about it everyone gets the same file just scaled for different injectors- If you have an ATP mani and T3s60 or a tubular manifold and a GT40 and you're both running 1000cc injectors, you both get the same file.

Without the dyno graphs I can tell you by the seat of my pants this car gains a huge amount of power by plugging a MAF in. After I have a DV I'll do more logs and we're planning out another AWD dyno day.

[gdoggmoney]

We're talking Maestro flashes, not soldered in chips.




I chatted this over with a few friends. There is no way to plug in a figure into a default airflow table and it's the same for every setup. Different turbos, manifolds, air filters, intercooler piping configurations, throttle bodies, intake manifolds, heads. When you think about it everyone gets the same file just scaled for different injectors- If you have an ATP mani and T3s60 or a tubular manifold and a GT40 and you're both running 1000cc injectors, you both get the same file.

Without the dyno graphs I can tell you by the seat of my pants this car gains a huge amount of power by plugging a MAF in. After I have a DV I'll do more logs and we're planning out another AWD dyno day.

Exactly, and I will show my hand which lends credence to your thoughts iwth your associates -- you ARE righ AND O2 feedback and regulation takes TIME, milliseconds which means lost power as you move up that tach.

So your running lean/rich on/off and basically correcting after the fact........... O2 correction was not meant to be the only thing the ECU uses to fuel.

Those hesitations and stutters I see with no maf in my car are lost power, and time where the ECU is fooling around with fuel/timing instead of actually making power.

[DougLoBue]

Exactly, and I will show my hand which lends credence to your thoughts iwth your associates -- you ARE righ AND O2 feedback and regulation takes TIME, milliseconds which means lost power as you move up that tach.

So your running lean/rich on/off and basically correcting after the fact........... O2 correction was not meant to be the only thing the ECU uses to fuel.

Those hesitations and stutters I see with no maf in my car are lost power, and time where the ECU is fooling around with fuel/timing instead of actually making power.

That is my exact thinking- we're only correcting fuel trims after the fact with the WB-02, running the MAF allows fuel trims to be adjusted before combustion.

[Marcus_Aurelius]

And how long have I beeing saying that and getting attacked by the MAFless Gestapo?

[wet0willy01]

Why not just run the TiAL QR?

[wet0willy01]

Ideally, you'd want to strategically locate your nozzles either way before the bypass plumbing (post intercooler) or right after the bypass outlet (pre TB). I guess thinking about a good spot to do the cold side DV relocation makes it easier to find ideal nozzle placement. I'll see if I can find pictures of my old setup with cold side relocation and multiple pre-TB nozzles.

The distance between the first nozzle (175ml/min) and the DV (routing back to the TIP post MAF) seem sufficient to you? TiAL QR- Snow performance MAP controlled.

[DougLoBue]

Why not just run the TiAL QR?

I was avoiding the Tial recirculating option due to the length of hose that would be required and my BOV is also in a tight space. Under the drivers frame rail and behind the bumper on that IC pipe.

[gdoggmoney]

Put my brand new maf in the housing on the intake pipe of the 3076 jetta. Amazing how the car runs after it ran horribly for 20 minutes. Runs horrible at cold start but when warm, aside from a light occasional rev hang the car misfires DRAMATICALLY less, almost 0 movement ever on the vacuum gauge.

New arm chair forum guy theory, due to setup differences load generated and air mass at given points will be way different.

I can drive through parking lots below 2krpm in 2nd, it does not sound like complete garbage idling even with the 3651 cat cams.

The car runs stupid rich mafless and the timing is always off somehow with rev hang, stutter on/off throttle and etc and lag associated.

New 1.8T trend, mafless to maf.

By the way, i run dual diverter valves

[doug@frankenturbo.com]

Pulling the MAF from our cars is like sitting in a 3-legged chair.

Way to go OP for finding your own tuning path.

[RaraK69]

on 1.8t me7.5

maf sensor is primary load signal when used, if unplugged it will default to the MAP sensor at that point, map sensor is limited to 1.5 bar of boost, after that it goes on correction for fueling post ignition.

install a bigger map and calibrate it, or use the proper maf + housing that your tuner has calibrated.

thats your solution to this issue. mafless is dumb or less you want a BOV, are lazy to plumb things, or making massive power (550hp+) where a proper maf calibration is not realistic or too difficult to work with. Even at that point promaf makes a nice solution and it will come with a calibration table to use

[DougLoBue]

I have a 4" pipe with a housing & V8 S4 MAF sensor. The scaling was done in Maestro to make it work.

I don't yet know how or even if the option is in Maestro to tune to a different MAP- I would like to one day though. You're using Pro tuner?

I'm looking for 500 awhp so probably around 625 crank with a 25% drivetrain loss estimate.

[18T_BT]

I'm going to venture out on a limb here and say to the claims of "it runs fine mafless and with a maf" shenanigans.

50+ AWHP is not running right, boost for boost no other changes.


This is a HUGE deal...... and obviously not "You can just go mafless if you want".

Well, let's see proof of this, really. Stating what you say at 50+AWHP gains is rather a blanket statement. I never ran a MAF on my car (well, not for a long time) and my car drives smoothly, get's good gas mileage and runs fast enough for me at over 400whp.

[DougLoBue]

Well, let's see proof of this, really. Stating what you say at 50+AWHP gains is rather a blanket statement. I never ran a MAF on my car (well, not for a long time) and my car drives smoothly, get's good gas mileage and runs fast enough for me at over 400whp.

I believe he is using data from my back to back dyno graph posted above?

[gdoggmoney]

I believe he is using data from my back to back dyno graph posted above?

[RaraK69]

I have a 4" pipe with a housing & V8 S4 MAF sensor. The scaling was done in Maestro to make it work.

I don't yet know how or even if the option is in Maestro to tune to a different MAP- I would like to one day though. You're using Pro tuner?

I'm looking for 500 awhp so probably around 625 crank with a 25% drivetrain loss estimate.

it may not be an option im not really familiar with maestro product. Id be willing to let you know what you need to have chris add though to make those changes.

Pro tuner? lol, not a product but a person

[18T_BT]

I believe he is using data from my back to back dyno graph posted above?

I must be old, cause I can't see any of the numbers on that chart...

[RaraK69]

Well, let's see proof of this, really. Stating what you say at 50+AWHP gains is rather a blanket statement. I never ran a MAF on my car (well, not for a long time) and my car drives smoothly, get's good gas mileage and runs fast enough for me at over 400whp.

Its plausible that the change alone to a MAF sensor could provide this power increase, due to the proper load calculation being done at that point. Though, without data logging i wont say for certain this is the exact reason.

You typically dont see much over 22 psi either Val, from past experiences, so going back to my previous post its very possibly you are not going to see much a difference with MAF until you exceed the MAP sensor's voltage cap, and possibly a certain % over that before correction starts to do its job.

You car should run well either which way(maf or not) just not to its full potential, we are talking about cookie cutter tunes here, maestro is a half cookie cutter tune even then, but will still be better than most OTS tunes once you work over some of the maps for your specific setup.

[gdoggmoney]

Its plausible that the change alone to a MAF sensor could provide this power increase, due to the proper load calculation being done at that point. Though, without data logging i wont say for certain this is the exact reason.

You typically dont see much over 22 psi either Val, from past experiences, so going back to my previous post its very possibly you are not going to see much a difference with MAF until you exceed the MAP sensor's voltage cap, and possibly a certain % over that before correction starts to do its job.

You car should run well either which way(maf or not) just not to its full potential, we are talking about cookie cutter tunes here, maestro is a half cookie cutter tune even then, but will still be better than most OTS tunes once you work over some of the maps for your specific setup.

That assumes that the load assumption/calculation/fudge factors by the ECU is correct. On my 3076 car with 3651 cats, the thing misfires lightly like crazy without a MAF, but with a MAF it's rock solid and pulls harder/smoother everywhere.

Timing at idle? Way less jumpy and much smoother, the fluidampr helpded some, but the new MAF sensor made it solid. Without said MAF? I can watch my vacuum gauge and hear misfires but the counter does not increment because it is not enough to change the crank speed really, but enough to be down on power and boggy/stuttery/hesitation.