I was just doing some reading and came across a possible stalling problem because the mass air flow sensor and where the blow off valve was loacated.

It makes some sense if the MAF is located on the pressure side and when the BOV opens the air would essentially be moving backwards across the MAF for a moment. Obviously depending if the BOV is located before or after the Sensor.

In my case the BOV will be located before the sensor creating that momentary cange in air flow.

Just wondering if there is any truth to this or should I consider running the MAF in front of the turbo to prevent any issure like this.

 

the main thing is you don't want to "blow-off" air that has already been through the meter "metered air" (after the sensor. between the sensor and throttle body) it will cause a rich condition. if you want to blow it off into the atmosphere, just have the valve before the sensor.

 

hes talking about having the valve before the sensor then purging to have the pressurized air purge backwards (thats already passed the meter) ? i think you could tune it and it would be fine depending on the setup. My 5speed 4.0 turbo is drawthru and the bov is vented to atmosphere

 

I ran my blow off valve right after the intercooler and before the maf. I don't have any stalling issues after blow off valve opens. Are you running a blow thru maf or draw thru?

 

This Is My First Turbo System I Ever Built Set-Up, It Has Not Been Fired Up Yet And I Have No Experience With BOV/ MAF Placement. Does This Current BOV/ MAF Placement Look Ok

 

Pic

 

Anyone?

 

Should be fine there-- the issue with some meters is that they like nice smooth laminar flow feeing into the meter. Sometimes having the valve or a bend placed just before the meter will result in weird signals being sent to the ecu. To cure this sometimes just clocking the meter in different positions will do the trick. sometimes is wont. THe air going back thru the meter should not be a problem as you will be in a idle table at that point anyway so it should effect it. If at part throttle, if the valve is slightly open, it can create turbulent airflow into the meter making part throttle act funny. Every setup is different so youll just have to try it.

 

If you look up JD's Peformance website they are one of the few dealers that deal directly with PMAS. They have Mass Airs that are calibrated for different elbows in turbo and supercharged applications. They also got me the best deal on one too. By the way your set-up looks good, and should make some nice HP!!

 

I got my Pro-Tube straight from JDS. They didnt ask me anything about where the elbows are located just where the BOV was. Im worried that the BOV being very close to me the meter will cause alot of disturbance & idling issues

 

The real issue here is not the idling but part throttle conditions such as surging and driveability crap. Clocking the meter is about the only thing you can do unless you contact PMAS for a new meter.

 

If you decide to change the MAF you might look into a PRO-M Pro Tube. This meter has helped a lot of people with part throttle issues and iddle issues.You can also get the meter calibrated lots of different ways depending on tune/piggyback ect... I talked directly to pro-m to get the the right MAF for me then i orded it from LM Performance. LM Performance offers discounts to TTF.com members. Mine was around $260 shipped. Good luck setup looks great

 

How much boost and HP are u planning to put down. Are those 42Lb/Hr injectors?

 

mustangcobra428: How much boost and HP are u planning to put down. Are those 42Lb/Hr injectors?

Im guessing your reffering to my set-up in the picture? Already have the pro-m Pro tube if thats what ur asking. Yes those are 42#'s in the pic also. Plan on making exactly 500RWHP @ 8-12psi limited to the stock block and injectors. Ive been buiding the turbo system for around 3 years now Im in high school and have no money, haha. I want to get the car done and hopefully make a couple low 10 sec. passes @ high school drags next year.