MAF placement: upstream or downstream?

[Bluevitz-rs]

With any luck I'll be purchasing a Greddy Turbo kit for my Echo in a few weeks and was wondering if it's better to have the MAF upstream or downstream of the turbo. I'll be starting out with just the basic kit Stage 0, so no intercooler. Also this will most only be for DD use, but might see the occasional track day.

I guessing I should leave well enough alone and just leave the kit the way it comes, but was just wondering what people's opinions are.

[cali yaris]

I think right before the TB is the usual placement. I have my MAP sensor there.

[Bluevitz-rs]

That's what I was thinking too, but the Greddy kit uses the factory airbox, thus using the MAF before the turbo. Because I'm thinking, if I add a BOV (probably a recirculating type) air will be metered even after the throttle plate is closed causing a major rich condition.

In my head the proper placement would be just before the TB, but after the BOV, so when you close the throttle air stops being metered and exits through the BOV before getting to the MAF.

[Nexus1155]

I see a lot of turbo kits having it on the inlet of the turbo, but i thought most ideally you would want it to meter air right before it went into the engine as where Garm says. Seems like you would get the most accurate reading of what is going into your engine at that location and that is quite important for the tune

[Bluevitz-rs]

Originally Posted by Nexus1155

I see a lot of turbo kits having it on the inlet of the turbo, but i thought most ideally you would want it to meter air right before it went into the engine as where Garm says. Seems like you would get the most accurate reading of what is going into your engine at that location and that is quite important for the tune

Yeah, and on top of tuning, the ECU would also know what the intake temps are and would be able to control knocking and ignition advance more effectively.

[lilredrocket]

Originally Posted by Nexus1155

I see a lot of turbo kits having it on the inlet of the turbo, but i thought most ideally you would want it to meter air right before it went into the engine as where Garm says. Seems like you would get the most accurate reading of what is going into your engine at that location and that is quite important for the tune

While this is great thinking. Why do both of the S/C kits for the Yaris have the MAF located before the S/C I understand with the Blitz you can't put in a MAF after the charge but with the PE kit the charge pipe runs right back by the MAF why didn't they put the MAF in the charged air?

[Bluevitz-rs]

^ It's probably designed to use the stock airbox too. Therefore it would require the MAF to be located before the charge in the airbox.

[Nexus1155]

Less risk of a CEL? lol

[lilredrocket]

Actually the PE kit comes with a cone filter. You can only use their filter because the intake pipe has a flange/plate that the filter bolts to.

[Bluevitz-rs]

Next question: would it be harmful in any way to the downpipe and manifold if I was to wrap it in header wrap?

[cali yaris]

Part of my downpipe is wrapped -- helps cut down the heat near (and right under) the firewall in my case.

As for the manifold I sent mine off to Jet-Hot.
http://www.jet-hot.com/

[Nexus1155]

http://www.techlinecoatingswebstore....o_X_Black.html

Only a thin layer needs to be sprayed, looks great, works great. Guy at our shop sprayed his manifolds and downpipes with some crappy HF canister gun and it came out excellent. Doesn't need to be a pro paint job :P but it layed out nice and even

[Bluevitz-rs]

My concern is more about it possibly cracking do to the heat being kept in??? Or should that not be a concern with a cast manifold?

[Nexus1155]

LOL doubt you need to worry with a manifold like this, nothing to it really, alot of cracking manifolds are from stress, The log really has no stressful areas as it is too short of a design and has no crazy woo doodley bends or long pipings

[cali yaris]

doodley bends, ha, good one.

but yeah, if it cracks it's not because it kept the heat in.

[Bluevitz-rs]

Thanks guys!