NC MX5

[The Bogan]

Question for people who "know stuff"

I am looking at doing the new intake like the one in the picture (the pictured is designed for the OEM TB and intake plenum), this design has the filter behind the front bar, but, the filter sits where the OEM duct heads into the front bar, and the standard aperture when the OEM ducting is removed allows the filter to pulled back out of the front bar into the engine bay for servicing, a simple blanking plate is used to seal the aperture behind the filter

This will require a 45° silicone hose from the TB, like the alloy pipe that is currently there, to another 45° silicone hose to get a straight run to the aperture in the front bar

Question: how will it effect the tune if I move the MAF about 100-150mm forward, the red is around where my MAF is currently, and the green would be where it would end up

Like this

This is the hole the filter goes through 

Ends up like this

LOL..Cheers

 

 

[MBS206]

My guesstimate, with no real numbers to back it up, is it won't effect it greatly at all.its not a huge change in position, and I can't see the air flow changing from in turbulence that much based on distance, and what's in front of it.

Johnny and Brad may have some more numbers to share from experience though.

[GTSBoy]

My thought is if you were just moving it forward and the upstream geometry remained the same, then no difference at all.

But because the current one has the filter direct into the AFM inlet, you effectively have the best chance of a completely symmetric air flow profile upstream, and in, the AFM, whilst the aftermarket inlet thingo has a (small, to be sure) bend between the filter and the AFM. That would bias the flow to the outside of the bend (downstream of the bend) which might well reduce the size of the signal seen by the AFM, for the same total flow rate. Having said that:

• If you're proposing to make your inlet look like a hybrid of your existing one and the aftermarket one, such that there is no bend where the filter is clamped on... then I say it will be just fine.
• If there is going to be such a bend, then, if you can align the insertion of the AFM blade such that it is at right angles to the plane of the bend, then there is a better than even chance that the centreline velocity where the blade is will remain more or less the same, and the velocity will just be a little faster to the outside of that, and just a little slower to the inside.

**This is not professional investment advice and you should consult a suitably qualified ouija board, tea leaves or the intestines of a goat for more accurate prognostication.