I just installed a Samco trubo to MAF intake hose. The Samco part is much smoother and slightly larger in internal volume than the stock hose which is necked down and full of pleats.

The car has seemed to lose power below 3500 rpm and the throttle response is not as good. Above 3500 rpm, it seems faster but the loss of power below 3500 might make it seem like the car is coming on the pipe harder.

Could the smoother hose and increse in internal volume throw off my MAF readings at low flow volumes/velocities?

Could I be in the wrong cells of the ignition and fuel maps now? Has anyone else experianced this sort of thing? Any work arounds?

As a side note, I forgot to plug my MAF back in and the car ran pretty well. On Nissans which I am more used to, the car goes into a horrible limp home mode and can hardly run and take throttle. The EVO just has some slight driveabilty issues. It feels like a poorl tuned Alpha N setup.

 

I installed mine about 7 months ago and never had any problems with it. I did have to richen up afr from 6krpm on up.

 

I am going to try to add timing below 3000 rpm and 140 load or so.

 

The 2 byte load waviers from idle to about 3000 in the 70-120 load cells so the timing fluctuates. So I smoothed out the timing maps and added a few degrees more advance here and its a little better.


Fuel is in closed loop in this area so I don't think adding fuel will help.

 

It does sound like it's affecting the MAF calibration at low flow.

The Samco is fairly soft radially compared to the stock piece, so I've wondered if it'll collapse at all due to inlet depression at high load. Apparently not?

 

pressure drop on mine is 0.74 psi with drop w/ moded cover oem airbox and 0.5psi with open element filter, hardly enough pressure drop to colapse it.

 

Thanks Jorge for the data. What did you use to measure it, and what location on the inlet pipe did you use to make the measurement?

 

I used the MAF baro following the same criteria for other filter tests here.
Using openport1.3 and logworks to datalog, idle it will register 14.87 psi and at WOT the pressure will drop to 14.13 at 7.2krpm, a pressure drop of .74 psi (there was no diffrence in pressure drop between samco and oem tip.)

OEM filter and unmolested box cover the pressure drop is about 1.13 psi.

Using a cone filter pressure drop is about .5 psi.

the brown line in the chart is the pressure drop trace of a oem box with drop in filter and cut top cover.

 

That was measured at the MAF, right? I want to be sure I'm understanding correctly.

 

correct.

 

In that case the effect of a new inlet hose would be very very tough to pick out since it is a downstream effect.

A similar thing would be to determine the pressure drop of a new throttle body by taking a pressure measurement at the discharge of the compressor.

 

2byte airflow may be a better way to determine that difference or better yet a dyno.

I did have to adjust (richen) AFR from 6k up, so it must be getting more air, that is why I kept it on.
I did DLL runs and the results are very similar to the results obtained in this thread
ebay filter for me it was <10