I'm running the MAF sensor before the turbo right now runs fine but when i come to a stop after boosting or not it still hits 10.0AFR. I was wondering if I put it after the turbo is there any advantage?

 

Are you running your BOV to atmosphere? My car did the same thing until I recirculated it. The only advantage to running by the throttle body on the boost side is incase you blow a intercooler pipe off. The Maf will still read and you can drive home. If your Maf is on the intake pipe and this happens you have to do the reapirs in a parking lot like I did. That's the only down side. I personally like running on the intake side due to the fact our Maf sensor also includes the IAT sensor in one package. So if on the boosted side it will read hot air. One of my inputs on my piggy back is this sensor so I get better performance the lower the IAT reads. Basically by advancing timing more. My Maf is right by the filter and the IAT at the most only reads 10 degrees hotter than outside air.

 

blow thru maf have few advantage, it allows you to use BOV thru atmosphere without rich stalling problem. It also reads a more accurate intake temp going to the manifold since its after the intercooler. And like the post above mentioned like if pipes get blown off. It also allows you not to use some intake pipes and improves air flow to the turbo by deleting that restrictive section of the setup.

 

blow through MAF all the way, otherwise you cant vent to atmosphere without issues.

 

also, if you ever have to remove the turbo you can use the upper pipe as a cold air intake instead of having to keep another intake for a backup.

 

S1 does it fine. I just recently seen a GR and a custom T-netics do it fine too. Downshifting is where it makes all of the difference.

To the OP, I guess it's what is easiest for you. The ONLY time I see a blow through being superior is if you are using the MAF to tune off it. With systems like the AEM FIC, GR E-managle, Ultimate, AEM EMS, Hydra EMS..all tune off of a MAP sensor. So, it's speed density tuning at it's finest. The APR would be the best candidate to tune off of a blow thru MAF, otherwise, it's just small transient throttle differences for the better. But still, it works fine on a pull through. The S1 does, has and still will since 2006; do well with a pull through MAF design.

Remember, flow is flow. Pull through or push through. 8 PSI on a T3/T4 57 trim is 8 PSI on T3/T4 57 trim.

 

It all depends on your set up. If your Maf is in the intake pipe just leave it there and recirc your bov. Or tune around it...your choice. I ran my bov open and recirc and personally I like the sound better recirc. Still loud cause its right by the filter anyways. When I ran open I didnt get the cool wistle sound through the pipe that I do now.

 

Yea thanks I'm running the AEM FIC it runs great. I just did have that happen where a pipe came off after the turbo and your right it doesnt drive to well at all. Also with my setup I would be easy just to move the maf to blow through. Is a retune in order after this change?

 

Yes I would recommend it because of small transient changes in throttle.

 

Adding to those advantages would also include a slight increase in throttle response.

 

Today I put the MAF after the BOV and before the throttle body. It totally messed up my tune on the AEM. The car would start then just die, got it idling a bit with messin with the MAP volts then but whenever I tried to give it gas it would just lean out. I finally just set like lower voltages on the MAP table to 0 just to run down the road. Should the MAF sensor be shielded from the boost cause the vacuum gauge would only hit -10ish as if the car was in limp mode. If anyone can lend some help for my AEM FIC tune it would really help. I'm going to be working on it all day tomorrow on it so I can get this baby running like she was.Thanks

 

Any idea why my car is going into limp mode then it trys to hit boost?

 

What BOV? How close is the MAF to BOV or a bend?

 

It is about 4" from the BOV but pretty close to the bend down for the throttle body. I was just talking to my friend who is a porsche mechanic and he brought that up about air turbulence. I called you shop earlier about coming up for a tune, he said the sensor might be backwards, I almost sure its not tho. I would be up there tomorrrow to fix this and a tune but im like 4hrs away.

 

Turbulence is probably a thing, which is why I was asking the questions I was.

It should be away from the bend and at minimum 6" from the BOV. Depending on the BOV, if it's for example a TiAL, it opens quite a bit and that in essence is pulling away air that's being metered close to the MAF and/or allowing more air coming in right before the MAF as well. This creates haywire!

 

Ok, thanks I'll work on it. I be in touch about setting up a time for a tune hopefully next month. I'm from east PA and I cant find anyone close that does good scion tuning.

 

Near philly by chance?

 

Yea, like 40min away.

 

when I first installed my custom turbo kit on my tC I first had the MAF between the intake filter and the turbo and it wouldnt even hardly idle and I couldnt even get out of first gear without it stalling. It was un-drivable. I finally realized I could switch to blow-thru style. Did that and I was running perfect idle and driving amazing. Mind you this was with no tune at all but I couldnt believe what a diff it makes. Amazing!

 

But, you grenaded your stuff mang! That doesn't count for an opinion John!



Just playing man. How is it coming? Any updates? Last I heard, you where in pieces!