NefMoto

Looks like I'm pegging the maf at ~ 24-25 psi. on a 2.7T. Sound about correct? If so, does anyone have any larger maf options that are reasonably priced, and will fit-ish in the OE intake tract? Thanks!

Bosch MAFs can read a bit higher than hitachi, if that helps.

Depends how much more room you need, but it is at least a cheap thing to test compared to a whole new housing.

Thanks for the quick response. Also would like to know people's opinion on what a stock longblock can handle (in the long run) with these turbo's at this pressure. Don't have access to a dyno at the moment, so can't post real world HP/TQ numbers. Car is a stock block 2.7 with WMI, upgraded IC'S and Tial 605's. Car stays right at the MAF limit at 25-26 psi (fueling good), and the owner wants 28-30 ish  :). He says he doesn't care about blowing up the engine, but I'm not hearing that of course.

500 wheel is about max on stock block.

Found this from a post by Julex

"From the looks of it, your V8 85mm housing should just about be ok for 605 in moderate boost but you will definitely hit the wall at anything over 25psi of boost and more air being pushed into the block.

I am hitting a limit of 85mm EPL housing which tapers from stock air box to 85mm to Rs4 accordion when I am at about 24psi of boost. My MAf logged MAF flow hits the max value and I slowly start getting lean on wideband. I since lowered to 22 psi since I don't want to kill my k04s but I think it would get even worse with better turbos like 605s."

Going to go with a 95mm for now...

HPX pmas, is what Daz always told me.

This is what I'm now considering. Either that, or the pro-M80. I was hoping not to have to ditch the airbox, and re-design the intake tract, but it looks like this could be my only option. Unless I can simply install this HPX sensor in the existing 85mm housing already on the car. On a side note, when I went to order a 95mm housing I was told by the place's tuner that the issue I was having was because of the OE Hitachi sensor, and moving to a larger housing would not solve my issue. Does anyone have any feedback on this? I also read a thread or two on here stating that these style MAF sensors do not correct for ambient temperature as well, or at all when compared to the OE Hitachi.

I hit the MAF wall (Voltage) around 24-25psi on an 85mm Hitachi on my 605's...

Just go HPX... no need to ever deal with anything else again after that.

Thanks for the response, VR. I see they have a few different maf sensors available. Can you suggest which would suit this application best? Sent an email, and called, but haven't heard back yet. I also saw a thread (maybe Julex) saying the HPX maf didn't correct for changes in ambient well, or at all. Has this been your experience as well? Looking at the HPX sensor, it seems the mounting points are similar. Any chance getting it to mount into an original billet aluminum 85mm housing?

HPX requires a different mounting flange (therefore you can't use it in your existing housing).

Why not use 95mm maf housing with oem RS bosch sensor?
I modified RS upper airbox to fit 4 maf
Oem look and it reads 670 g/s so far.

Thanks for the suggestion. I'm open to any and all options, just trying to decide what's best in the long run, as the engine will most likely get built soon. Pic of your intake? I assume you mean OEM RS4 sensor?

I am using oem RS4 airbox

Oem RS4 sensor, correct.

I haven't seen any issues with the HPX, that said I've only done 1 car on it.  But let's be real here, the HPX sensor is used in draw through and blow through on many different ECU's and cars (it's very popular with the stock ECU BMW crowd) and they don't seem to have any issues with it at all.  They exclusively run it in blow through as well.

The one I tuned was a regular (not extended) HPX sensor in an 85mm housing.  Nothing special there.