blow thru maf on rb20

[carl h]

anyone running this setup?

i have a greddy emanage so i should be able to tune it out, anyone with any info on how to do this please reply, searching didnt help a whole lot.

[discopotato03]

Interesting concept , not sure how the AFM would cope with positive pressure on it . Computer may go slightly haywire because post turbo air will not be ambient temperature so its in built corrections may be all wrong . Advantages may be higher flow because of higher than atmospheric pressure on its inlet side but its debatable whether it can generate a suitable signal voltage for the higher mass flow , my guess is not . Unless its impossible to package for some reason I'd run it like Nissan intended it , why re-invent the wheel .

Just my two paseo's worth , A .

[Sydneykid]

I have seen a GTR with a 90 mm Q45 AFM plumbed in between the inlet plenum and the intercooler. Saves the reversion problem with big cams and turbos that you can get when the AFM is located just before the turbo. That GTR had a Power FC, I don't think the Emanage has anywhere near enough adjustment parameters to handle the necessary tuning changes.

[cameron]

SK,

Would setting up your afm this way have any affect on:

Drivability of the car ?

Performance wise ?

[carl h]

the emanage has a 16x16 map so i imagine that a good tune can be achieved with it.

some one on this forum setup a car with a blow thru maf using a emanage, but i cant remember who.

[Sydneykid]

SK,

 

Would setting up your afm this way have any affect on:

 

Drivability of the car ?

Performance wise ?

 

Hi Cam, I have only seen it done to fix driveablity problems on cars with big turbos and cams. So I guess you could say it improves driveability on them, otherwise it wouldn't be done. I have no idea what it would do to driveability on a less radical engine. Maybe that's the answer, don't bother unless you have that problem.

Not sure what you mean by performance. If you mean power output, than I can't see why it would give any performance increase, I can get accurate A/F ratios with the AFM in the usual place. Except I guess, as per above, when the big turbo/cams problem causes a drop in performance.

It is also handy as you only have to run one AFM, a 90 mm Q45 fits nicely in the intercooler to plenum/throttle body pipework. Plus you get to do the Japanese "thing" and run the turbos open mouth..........

[mambastu]

I have a twin turbo RB25DETT in my S13 and I'm using an E-manage with a Z32 MAF after the intercooler in a blow through arrangement. It works really well.

I trialled it on my old CA18DET before I fitted the RB25. It worked well on that too at boost pressures up to 23psi but I found that you need to have reasonably stable airflow through the MAF.

On the CA I had around 6 " of pipework between IC outlet and MAF and 6" between MAF and throttle body. On the RB25 I have around 12" before the MAF and 12" after and its easier to tune as the metering seems to be more stable.

It also use a vent to air BOV after the turbos and before the MAF and I don't get any nasty overfuelling when the valve vents.

[carl h]

wow that looks fantastic!

hrm ok so it can be done.

check you pm box.