MAF placement? Change due to upgrades

[1sikS13]

So this year im upgradeing quite a few things with my KA-T setup. Like going to bigger top feed injectors, GT3071R turbo, Q45 TB. I am looking to push round 20 psi shooting for 400 or so. Thing that concerns me is my MAF. I was runnin a Z32 earlier as a suck through setup, runnin 10psi. Should i stay that way? My new turbo has a 4inch inlet, the Q45 is roughly 3 inches. Should i switch the MAF over to blow through? Which is more efficient? Thanks for your opinions.

[GTR PrYdE]

Isn't the Q45 maf 90mm? If so that seems WAYYYYYYY TOOOOO BIG for 400whp.

The Z32 maf is proven for 500whp, so i'd leave it

[1sikS13]

anyone else, on the blow through or suck through opinion

[C-Kwik]

So this year im upgradeing quite a few things with my KA-T setup. Like going to bigger top feed injectors, GT3071R turbo, Q45 TB. I am looking to push round 20 psi shooting for 400 or so. Thing that concerns me is my MAF. I was runnin a Z32 earlier as a suck through setup, runnin 10psi. Should i stay that way? My new turbo has a 4inch inlet, the Q45 is roughly 3 inches. Should i switch the MAF over to blow through? Which is more efficient? Thanks for your opinions.

From the standpoint of metering air, there is no practical difference between running a hot wire style MAF in blow-through or draw-through arrangements. Draw-through has a very slight advantage as the difference in temperature between the metered air and the wire's temperature will be greater, but unless you are running it in the hot pipe with a ton of boost (very high air temp), its not going to be significant enough to worry about. I'd probably not locate it on the hot pipe anyways just to reduce the level of heat on the materials of the MAF. *EDIT: to be clear running it on the cold charge pipe would be just fine)* Enough supercharger/turbo kits are installed in blow-through configurations that they have shown such a configuration is not a problem.

The short answer, do what is easiest.

[hannibal]

What are you using for an ECU? Just thinking about MAF and BOV. I THINK the MAF should come after the BOV if its recirculated. Just something else to consider.

Based on C's advice, I'd put the MAF on the cold pipe.

[GTR PrYdE]

Yeah def put the Maf on the cold pipe, with the maf between tb and bov...

[C-Kwik]

What are you using for an ECU? Just thinking about MAF and BOV. I THINK the MAF should come after the BOV if its recirculated. Just something else to consider.

If the BOV is located ahead of the MAF, it will not need to be recirculated as any air diverted through it will not be metered. Its a small bonus. Frankly, putting the BOV ahead of the IC would reduce some of the thermal loading the IC will see as the IC will not be forced to cool down some air that will not be going into the engine.

Do make sure there is plenty of space between the BOV and MAF and MAF and TB to reduce any effects of turbulence from either.

[1sikS13]

well at this point i have 2.5 in. hot and cold pipes. I wanna change just the cold side piping to 3 in. out of the IC, because the Q45 TB is 90mm. This way it will be a similar diameter for MAF. I will still be leaving the BOV on the hot pipe. Anyone see discrepancies with this?

[biggie]

I just use the blow through to not have to worry about blowing off a coupler and not have to stop or have issues with it.

[C-Kwik]

well at this point i have 2.5 in. hot and cold pipes. I wanna change just the cold side piping to 3 in. out of the IC, because the Q45 TB is 90mm. This way it will be a similar diameter for MAF. I will still be leaving the BOV on the hot pipe. Anyone see discrepancies with this?

That should be fine.