TurboTim

We have always been intrigued by the idea of setting up the 951's with a blow through style MAF system.So I decided to make it happen and test it.We incorporated the sensor right into the intercooler pipe that leads to the throttlebody.The Tial 50mm blow-off valve is right before the sensor and there is now a straight pipe with a filter leading into the turbo intake.On a local test car we had here,it has worked really well and there is no weird idle or drivability issues either. I have a set-up like this on my 350Z twin-turbo and have been runnng it like that for about two years and it runs exceptionally well also. Another benefit is the chances of sucking in unmetered air a dn possibly detonating, like you can with a conventional set-up is pretty much null and void. Unless you dont tighten up the silicone hose between the intercooler pipe and throttlebody,there is no way to suck in unmetered air(unless of course you didnt tighten down your intake manifold).The best part about this particular system is that it can be set-up to "upgrade" the MAF system you already have I will post some pics when I get a chance.

TRP951

sounds good but what about oil in the IC pipes and such wouldnt that mess the sensor up since a light oil is normal?

TurboTim

It shouldnt be a problem as long as massive quantities of oil arent soaking the sensor. With a blow-through set-up like this I pull the sensor every 6 months or so and blow it off with some compressed air.You can actually get oil mist on your MAF sensor with a draw through MAF too.You can get the oil off of your K&N airfilter if you have just serviced it and when you are idling and cruising in vaccum your bypass is open and it allows air to circulate between the TB and MAF.

fast951

Tim, Good idea, all of the MAF we now sell can be used as blow-through. So are you making the IC pipe so a sensor can go in-line? Or are you removing the actual element out of the MAF sensor and inserting it into the IC pipe?

eniac

My concern with this type of MAF setup is how would it handle say 30psi of boost...or more?

TRP951

would there be any advantages over your setup that we have john converting it to a blow through since I have one of your MAFs already?

fast951

There are a few advantages to a blow-through setup, however I'm not sure you will experience much of a difference.
- If the existing MAF is causing a pressure drop as a draw-through, then you can minimize it with the blow-through. Unless you are using a HUGE turbo (4" inlet) and lots of boost, I wouldn't worry about it
- If you want to dump the BOV to atmosphere, you can with the blow-through IF you connect the BOV before the MAF.

The problem I see with a blow-through is a vacuum leak on the pressure side of the turbo before the MAF can go undetected.

Sorry Tim, I don't mean to take over your thread. I'll stay off, but I'm interested in your findings.

Ski

has someone improved on the temp probes and their grommets for this type of setup? the ones I've seen and run will not take the boost, just wondering what people would do/have done with this - now a bolt through or threaded item?

sawood12

What about the longevity of the MAF due to the airflow being a higher temperature? Should you expect its life expectancy to be lower in this configuration?

Is the Vitesse MAF a hot wire MAF? I think the 928 MAF is a hot wire MAF and when you turn the engine off a large current flows through the wire to burn off any oil deposits. If the Vitesse MAF does this then I can't see the oil in the induction system being a problem unless it is excessive.

TurboTim

we are removing the element out of the sensor and welding the bung to the inercooler pipe so you can screw then sensor into the pipe.Much easier and cleaner.The sensor we use has a sample tube and we determined that if you remove that tube the ID of the pipe is close to that of a 2.5" pipe.The velocity will be a bit higher in the intercooler pipe which will help the MAF read consistently.Pm me when you get a chance.I would like to talk to you about some stuff.

TurboTim

John,

Dont worry about this being my thread or your thread.It is the communities thread.It is good see see all sides of the equation and everyones concerns. Like John said a boost leak could go undetected to some degree.You will probably see it on your boost gauge if it is severe enough.The good thing is that there will be only four hoses that would cause a boost leak and those are the hoses from the turbo to intercooler and the intercooler to tb.As long as those are tight and there are no cuts,etc..... you should be aok on the pressure leaks.The other nice thing is that you will still get the proper amount of fuel with a boost leak, you just wont make the power.

Ski,

We could weld a bung to the IC pipe so you could screw the MAT in.We have used a Bosch style temp sender which is threaded.


Sawood,

As long as your intercooler is relatively efficient you should not have to worry about the temperature destoying the MAF sensor. It would take a tremendous amount of heat to hurt the sensor.



Tim

TurboTim

Eventually, you will run into a wall with the amount of airflow the sensor can handle before it maxes out.It could be a 25, 30 or even 35 psi.We dont kow yet.But in all fairness,I have yet to meet anyone that has run 30 psi of boost in a 944 turbo

5speed300

This is the way lots of the aftermarket bmw FI guys are now going. Correct me if I'm wrong, but doesnt this type of setup allow you have infinitly adjustable boost pressure (between a certain set of values) while still receiving proper fuel amounts?

TurboTim

Here is a pic of the MAF sensor bung we CNC'd for the pipe




Tim

eniac

There are a few boost addicts in the 944 world I run either 23 or 27psi boost, I have a button on my wheel to switch. I have gone over 30psi when a wastegate hose popped off. The car was insanely fast, I was having so much fun that it took a few runs before I noticed the boost gauge pegged on the pin at 30psi. I currently have 83# injectors but would go even larger to add more boost if only I could get the car to idle with 110# lol

Anyway I am very interested in your findings. This setup has been great interest to me for some time. I currently run a MAP so I can eliminate everything before the turbo plus be able to use a atmosphere dump BOV. I know I can get more power out of a proper MAF then my MAP. Good work with this so far, I can't wait to see your final results