blow thru MAF

[boost-addict]

ok, so this might get shot down in flames, but can i ask is there any benefit? im wondering if the sensor works under pressure. and thinking the maf would get a more accurate reading after the intercooler as the temps and flow would get read better.

am i talking out my **** and best to have it before the turbo as is?

reason im asking is the way the box is set up on the a4 is terrible. the air box is like 6" from a red hot turbo. even with the heat sheilds the intake temps must be something rotten, after a run the box and intake pipe are really hot. i know the intercooler cools down the air any way but having high intake temps to the turbo cant be doing any good to the temps.
so was going to pipe directly from the turbo to a intake like a cda one, away from the heat then vent the crank case to a catch can and then have the recirc running from before the maf (after the intercoler) and back to the turbo intake pipe.

possible or not worth it? sorry if what ive suggested is a stupid, but ive searched and not found much. only on other cars that use the maf before the turbo as per the 1.8t

 

[aragorn]

Air Mass (which is what the sensor measures) is the same pre and post turbo, for fairly obvious reasons! The temp sensor is already mounted in the inlet manifold, so nothing gained there either.

I'm not really sure theres much point in doing it. The MAF calibration is designed for where its currently located, and its designed to be used in ambient air. Sticking it post turbo in a pressurised situation is unlikely to gain you anything at all, and is entirely likely to cause calibration issues.

As for all the heat around that area, sure the parts get hot, but what you forget is the speed that the airs travelling at. At peak flow, the airs flowing thru the MAF housing at something like 120mph. The amount of heat the air will collect from the pipework as it whizzes by is fairly insignificant, especially compared to the heat that gets chucked into it when its rammed thru an inefficient turbo compressor working waay outside its comfort zone.

Your far better off spending your time/effort sorting out a decent intercooler and ignoring the air intake. The other issue with these cars is the standard turbo is only good for about 200hp, which it will more or less make on completely standard parts, so while you can mess around with every bolt on mod under the sun, your not really going to gain anything.

If you want to tune your car, my advice is to sit down and decide exactly how much power you want from it, then build a plan of action around that figure. Randomly throwing parts at the car without any plan just ends up wasting money.

 

[boost-addict]

Air Mass (which is what the sensor measures) is the same pre and post turbo, for fairly obvious reasons! The temp sensor is already mounted in the inlet manifold, so nothing gained there either.

but the the temp sensor can still be placed up stream of the turbo

I'm not really sure theres much point in doing it. The MAF calibration is designed for where its currently located, and its designed to be used in ambient air. Sticking it post turbo in a pressurised situation is unlikely to gain you anything at all, and is entirely likely to cause calibration issues.
which can be dailed in on a custom remap surely. if a mafless tune is capible then a blow thru maf surely can be done, its done across other models of turbo engines, which is why im asking specifically about the vag 1.8t system

As for all the heat around that area, sure the parts get hot, but what you forget is the speed that the airs travelling at. At peak flow, the airs flowing thru the MAF housing at something like 120mph. The amount of heat the air will collect from the pipework as it whizzes by is fairly insignificant, especially compared to the heat that gets chucked into it when its rammed thru an inefficient turbo compressor working waay outside its comfort zone.

yes which is why i said what i said. a ko4 would be what im using. either a 015 or see if i can use a 020 and use a k24 compressor wheel. either way with a decent fmic i could run 25psi with out issue as far as im aware. i know thats over its effecency range but with a good tuner like r-tech is easy done.

Your far better off spending your time/effort sorting out a decent intercooler and ignoring the air intake. The other issue with these cars is the standard turbo is only good for about 200hp, which it will more or less make on completely standard parts, so while you can mess around with every bolt on mod under the sun, your not really going to gain anything.

well i know the standard air box flows to 300hp. but when i want to run close to that then i dont want to be holding any thing up if possible. my plan with the intake was to buy a tip and cut it half way, so practicly in half, use a conneting pipe to allow the top part to spin 90 degress so then the inlet would be pointing towards the wing, rather then the bulk head, and run a box like bda in front if the wheel arch lining. even if i have to cut in to it slightly to mount it.
i never suggested i was going to drive in to halfords and hope to drive out 200hp better off.

If you want to tune your car, my advice is to sit down and decide exactly how much power you want from it, then build a plan of action around that figure. Randomly throwing parts at the car without any plan just ends up wasting money.

my plans are vxr injectors, 100 cpsi for example Race Cats , Race Catalysts , FIA approved catalytic converters from Eurosport Exhausts or Catalytic Converter High flow Sports Cat 100 Cell 3" | eBay

with a 3" down pipe to a 2.5" s/s system. had all that priced up and im happy with that, but main prioritys are fmic with all hard boost pipes. and turbo intake pipe. for now, may even chuck a ko3 remap on that while i build up my kit. as im not minted and couldnt afford one kit all at once, it is even possible ill be considering a 2871 as its really not that much more cost wise, then at least that way running 25psi on that turbo would work less then a ko4. and then as and when funds allow i can upgrade other bits to get over 300hp. but for now im only looking for 270. and a ko4 is at a stretch to achive that, and also lets not forget i have a tqs which has a ajl 180bhp version in the first place so i do belive my pump is more then capible. but i would make sure and just lilley use a inline pump to boost pressure and consistancy across the map. so i do have a plan as such, just not any thing in place for defenate as i hate bothering comapnays lining up work and then saying i only wanted to find out. so when i have the cash then ill do the sorting. i have a fmic on its way, granted its not a brand name but from what i can see its good enough and states flow up to 650hp.
any how but back to the maf i asked becasue i wanted to know if it was possible. is it worth having it like that IF ITS USED IN A CUSTOM REMAP?

 

[aragorn]

The temp sensor is already upstream of the turbo, its in the inlet manifold, so its seeing the actual temperature of the air entering the engine.

MAFLess can't be done on M3.8, and IMO its a stupid idea anyway. Its done in america because they're all lazy and dont have proper tuners.

There really isnt anything wrong with the stock airbox. Add another cold air feed to the bottom of it like Audi did on the RS4 and it'll happily flow 400hp. If you want to waste time, money and effort installing some cone filter hacked together mess then thats your call.

Your fuel pump is the same part used in the S4, so 300hp wont be a problem for it. If you want 300hp, then dont mess around with a hybrid or a K04, just buy a GT28RS from the start. This is what i mean by planning a build. Getting the most from a K04 hybrid means big manifold, big TIP, big downpipe etc etc all of which are K03/4 specific, then when you get annoyed that its only making 257hp and want more, all of that goes in the bin as it all needs changed to fit a proper turbo. If you want more than 250hp, reliably, then a K04 hybrid is not the way to go on these cars.

I'm not really sure what you aim to gain from moving the MAF, bar adding complexity where its not required. Could it be made to work? Probably. Is there any point? No.

 

[boost-addict]

which is fair point, now dont think im not taking your advice, and experince in, as i truly am. but it seems others have done so and came across this

Draw through vs Blow through MAF

now if theres really no point and there isnt any benifit then ok thats good to know

also the iat in before the turbo, so its not seeing how hot the air is entering the turbo rather only what tempreture the box is being heated up to if you understand me, i understand the air flowing wont soak any heat at full flow but with a iat stuck in a hot box then would that not be better on the out let housing of the intercooler so the engine can really see what temps are going in

my view on the maf was, draw though is fine dont get me wrong but when its blown though then wouldnt the maf work out better fueling etc on the fact its seeing whats entering the engine rather then were it is just metering air in to the turbo which by time it gets to the inlet manifold has a totally diffrent desity/mass then when it entered the intake system.

do i talk rubbish or am i on the right path of thinking

also ive seen mafless tunes do very well using map sensors. any how im not on about going mafless as its not worth that. and i dont see why your so down beat about what im saying.
how is a bda intake being hacked together, rather you suggest hacking the original box up to install a cold air feed. then which has to hit walls in the air box before being drawn in to the maf via the trumpet, which is obvious there because turbulence would be bad in this case. now im sure its fine,

so what your saying is no one has ever bothered using a blow though maf on a 1.8t? sure i see a golf vr turbo's with the maf before the tb/after the ic

 

[aragorn]

the IAT is in the INLET MANIFOLD! IE its after the turbo and intercooler, and sees the air actually flowing into the engine just before it hits the valves... Its completely unrelated to the MAF sensor.

You cannot alter the mass of air. Thats a fixed value. If the turbo sucks in 100g of air, compresses it and heats it up, you've still got 100g of air, its just hotter and under pressure. This is why the ECU works with and measures air mass, and not air flow.

The velocity stack on the MAF is there to ensure laminar flow thru the sensor, this is less easily achieved in a blow thru setup (or incidentally thru some horrible aftermarket filter)

Your link even says this, and provides no benefits whatsoever of actually using blow thru other than some vague issues with recirculating air which isnt a problem as the pipework for that is already in place.

I dont like aftermarket filters, because they dont actually filter properly. Not only that but the "enclosed" type of filter has been seen to cause issues over on the A3 section because the element inside is far too small and it actually becomes a restriction. They also almost always look a mess, because you remove the nicely crafted airbox, and in its place mount some shonked together filter held inplace with random bits of steel and cable ties.

Maybe i'm coming across as negative, but i just dont see the point in changing something that works fine just for the sake of changing it. All your doing is adding the possibility of problems, but without any benefits. Concentrate on the actual parts that need to be changed.

If i were in your position, i'd sort the exhaust and intercooler, and leave the downpipe, TIP and everything else until you sort yourself a bigger turbo and an appropriate manifold (i like the PSI Concepts one). Once thats sorted, then you can have the 3" downpipe made to fit the GTRS, and fabricate a TIP to connect the big turbo to the airbox and enjoy 300hp.

 

[boost-addict]

the IAT is in the INLET MANIFOLD!

If i were in your position, i'd sort the exhaust and intercooler, and leave the downpipe, TIP and everything else until you sort yourself a bigger turbo and an appropriate manifold (i like the PSI Concepts one). Once thats sorted, then you can have the 3" downpipe made to fit the GTRS, and fabricate a TIP to connect the big turbo to the airbox and enjoy 300hp.

sorry thought the iat was the bit on top of the box with two plugs.

yer well tip is on the list and fmic is on the way.

well if thats the case then that cool, never harmed asking and im not one to blank someones experince and knowlage. i know quite a bit about cars but mostly the older sytle systems, never had or been involved in vag engines and never a 1.8t so the way it all works is very strange to me, of course it all works how its ment to but some things to me seem **** handed.

well the 2871 or even a eliminator turbo wont come for some time. so i might well plan to just buy a esutuning decat and then have a system made from there, then when times comes for a mot or the gt28rs ill use a 3" 100cell cat, as id rather it have a cat then not.

so for now, as bt plans arnt going to be for 6 months or so, get the fmic,decat and remap. i only want to remap as what ever chip or flash this ecu has then im hitting 18 and then running out of puff at 6k to 10psi. and throttle response is a bit bad, i relise this can be down to many thinks like leaks etc but i really think what ever map it has from langlys its very crap. have a graph i can photo if you wish to see it

 

[aragorn]

tbh i doubt the turbo has much more than 10psi to give at 6k, its simply not big enough to be able to hold much more than that. Do you have a dyno plot of it at that boost level?

My standard tune hits 12psi peak and tapers off to <8psi by the time it gets to 6k.

 

[boost-addict]

right took better pics, so heres the paper work that came with the car. can connect to the ecu not tried vagcom but seprate issue, but what they put here makes me wonder if they fecked the ecu some how?

and heres the graph, no psi graph but mine goes up to 18psi then drops off, i dont mind getting a vid and showing you how its boosts and how it scales to revs

 

[aragorn]

yeh looks like a very mild map if its tuned at all...

Probably a map intended for a 150hp engine.

Get it into somewhere like R-Tech and they'll sort you out.

 

[boost-addict]

ah right ok, its very peaky eairly on but just feels like it goes no were, has no power off the line,

what i was saying few posts up, with fmic and decat is it worth getting the ko3 mapped for now just for a bit of fun, and maybe might be happy with what i get, at least then theres a map with r-tech for them to build on to once a bigger turbo. injectors etc are added

 

[Jason.s]

Boosting to 18psi but makes 169bhp and 200ft-lbs? So less power than standard but more torque? WTF map has that got on it..I`d probably be inclined to bin that off first and get it done properly also making sure it hasnt damaged anything in the process.

My Rtech map at a bar of boost did 199 and 221ft-lbs

 

[boost-addict]

exactly. it feels slower then my golf gti mk3. well on my way out so going to grab a vid.

 

[boost-addict]

right not the best becasue altho im on a 70mph road i cant get to 5th really as id be speeding. :busted_cop:

also excuse the getto gauge install. just an old one i had as waiting for some black smoke ones to turn up along with the pod mount for the a pillar
altho this only hits 17psi i do get 18psi on in 5th on a clear run
any way.

 

[aragorn]

yeh it looks like your getting a big spike low down then it just drops off and gives you more or less standard power up top.

Problem is that most tuners just flash on generic files, and these files have to be nice and safe and universal.

Getting someone like R-Tech to sort you a proper map that can extract the best from your exact setup will result in a much better end result!

 

[boost-addict]

yer i will. shame i havent a ko3s, but thats life and for now its ok, wouldnt mine some decent power, but of course thats never going to happen properly on a ko3. also it has a smic so maybe even if it isnt a generic theres no point in mapping for max power when it dosnt have a fmic to cool things down. parts seriously need to hurry up, i have 6 things comming and ive got a card from yodel apprently i missed them today, so have no idea which parcel its going to be lol


also when it says unable to remap due to config mismatch is this a concern on top of the fact a bosch scanner comes back stating "no systems found" ?

 

[aragorn]

Prawn managed 230hp on his stock sidemount (and a K03S ofcourse) on his A3. AFAIK the only mod he had was an upgraded downpipe, but the A3 downpipe is much worse than a standard A4 one anyway.

I'm aiming for a similar figure on the missus car with minimal components changed, and it'll be staying on its standard exhaust and intercooler. If it only happens to make 220 or 225 then that'll have to do!

You cant map the AJL ECU via the diagnostic port anyway, so maybe they tried that and it failed so they gave up?

 

[boost-addict]

well thats news to me, and thats fantastic to know.

really need to find out how to get in to the ecu as this scanner isnt plaing ball. tried every variation of models. but no luck. so need vag com pro. or at least vcds-lite to see if its the plug or just the fact the scanner isnt compatible.

hopefully some ones got vagcom pro near sevenoaks kent

so what is litery the max a ko3 will make with a fmic 3" decat and 2.5" system. and some kind of uprated panel filter, thinking pipercross

also why i have your brain on this thread, i did start a thread about heat wrap. im planning to completly wrap the decat and downpipe and as far back as i can get with what ever i have left, but i want to do something with the hot side, found wrap thats able to withstand 2000 degree direct and 3000 radiant. is it worth wrapping the hot side, or using some kind of turbo blanket? thing is a turbo blanket is expencive for what it is

 

[aragorn]

jasons result above is probably indicative of about the best you can manage on a standard K03-005.

Personally trying to keep MORE heat into the already scalding hot turbo isnt a great idea. It just pushes the EGT's higher and further into the danger zone.

By all means wrap the downpipe if you fancy, but i'd be leaving the turbo and manifold alone.

 

[jcb]

isnt the point of a MAF to measure actual ambient air mass entering the system and still allow recirc boost charge to be kept in the system without affecting the overall charge measure?

A downstream MAF would measure charge volume (or mass obviously) but would face issues if you continued to recirc the charge on lift off.

cant see it being any advantage other than the "cos I can" modification.

 

[boost-addict]

it dosnt matter if the maf is post or pre turbo. and the maf is messuring mass air flow. but point i was trying to make is, its reading x amount of temp and mass, once it hits the turbo, goes thought the ic, then its in a diffrent state, same amount of air but diffrrent pressure and speed.

a maf pre turbo isnt there to create a place for a recirc valve, its the face the maf is before the tuebo means there needs to be a recirc valve.

recircing boost before the maf wouldnt mean it causes problems means the dv cant be near the maf as itll create turbulance in the air before the maf

i personally see no reason why it wont work and there are advantages, but then there is disadvantages just like a pre turbo maf.

 

[murran]

the maf is messuring mass air flow. but point i was trying to make is, its reading x amount of temp and mass, once it hits the turbo, goes thought the ic, then its in a diffrent state, same amount of air but diffrrent pressure and speed.

but the airmass doesn't measure air pressure or air speed. its called an airmass because it measures the air's mass.
if your struggling with the concept...... Mass - Wikipedia, the free encyclopedia
just leave the airmass where it is, your flogging a dead horse.

i too hate silly aftermarket cone filters, in fact i got banned a few weeks ago for sarcastically moaning about someones huge cone filter in the 8l a3 section. so i wont go into that for fear of moderators wrath.

 

[boost-addict]

all im asking is, if maf draw though is "x" and maf blow thou is "y"

then does the maf read better at x or y as i read if the maf is at y then your get better throttle responce. there wont be so much lag between it reading the air then situated at x.

like you say mass is mass but i wondered if the advantage of having the reading before the tb at y means you get better drivablity.

but as above if it infact makes no diffrence then thats fine, no harm in asking

 

[jcb]

recircing boost before the maf wouldnt mean it causes problems means the dv cant be near the maf as itll create turbulance in the air before the maf

that is exactly what it means.
you would be measuring charge volume twice.
same way if you run a dump valve (no recirc) you can end up with funny lamda values, especially on higher boost applications.
MAF is designed to be draw through at ambient pressure.

what advantage do you think it will create?
You will never get NA throttle response when you have physical limitations/restrictions in the intake and exhaust system.

you can tune out any lag with various tweaks but its a turbo system afterall. the gains in torque are met with limitations in various ends of the rev range

 

[boost-addict]

well a maf has been used in blow though systems, i was understanding that air after the turbo/intercooler the air could be read more clearly.

like i said if there isnt a clear advantage then fine

also it wouldnt be read twice. as you wouldnt need to recirc. any how it was just a question that i couldn't find answered else were

does anyone here run a relocated bov/dv or maf?