[slowspeedsubi15]

New to Subaru. Purchased a used wrx. Installed accessport never really payed attention to anything until I started to notice that after a couple of days with the tune installed (stage 1 93 +for the cold air intake) it started acting weird in boost. Notice my dam at first was 1.000 and the car ran amazing, after a day or 2 it would go to .825 and when it started acting weird in boost it was .625. But it isn’t loosing boost. I just refilled the fuel. So I know it’s not the fuel. I did an oil change. When I first installed the accessport I don’t remember having this issue but I also didn’t have the cold air intake on it.

 

[WRX-maniac]

What intake is on the car? Cobbs map requires their brand SF intake. If you have another brand intake on there (aem, perrin, GS) and think that the cobb intake map will work you are wrong. If you do indeed have the cobb sf intake, then contact cobb. Along with their map, accessport, and parts you get their customer support.

 

[PilotRudy]

I have a Perrin intake and just got my Cobb access port today. I was getting -5.6 FKL and .625 DAM with just the stage one tune. Switched to stage 1+ big SF and problems were solved. 1.0 DAM and the usual random -1.14 FKL.

 

[XJman]

I have a Perrin intake and just got my Cobb access port today. I was getting -5.6 FKL and .625 DAM with just the stage one tune. Switched to stage 1+ big SF and problems were solved. 1.0 DAM and the usual random -1.14 FKL.

Thats not how this work, that tune explicitly states it only supports the cobb intake. The following is why this is important and was recently posted AGAIN by zax

ANY ICE requires proper metering of air and fuel in order to properly function. In the carburetor days, this was accomplished using jets and "signal" (the pressure of the air during and after the venturi).

With the advent of fuel injection, it is necessary to determine the amount of air ingested by the ICE in order to deliver the correct quantity of fuel. There are different approaches to this, but by and large the most common are to use an MAF sensor OR airflow density monitoring (IAT and MAP sensors). Since modern Subarus are MAF-metered from the factory, we will focus on that approach.

An MAF works by measuring the loss of heat energy from an energized wire. This is determined by the change in the resistance of that wire which can be correlated to the energy loss from that wire. In a closed and laminar-flow system, the loss of energy from that wire is dominated by the speed of the airflow in that system. The car's ECU can accurately estimate the air consumption of the ICE by closely monitoring the change in resistance (and thereby voltage in a constant-current circuit) of that energized wire (MAF sensor).

The trouble is that the MAF sensor does not DIRECTLY MEAUSURE airflow, but correlates airflow to voltage through a calibration table. There are many things that can change the calibration -- most notably the diameter of the MAF sensor housing, the placement of the MAF sensor within that housing, and the airflow characteristics around the MAF sensor (eddies, currents etc.).

While it is true that under low engine loads, the CLOSED-LOOP fueling algorithm which involves oxygen monitoring hardware in the exhaust will compensate for scale errors, closed-loop fueling is limited in what it can correct. Under the right circumstances, the ICE may run dangerously rich or dangerously lean and both conditions can cause irreparable engine damage. Lean conditions may cause engine knock and burned valves due to high combustion temperatures. Rich conditions (while typically safer) can cause cylinder washing, oil dilution, and eventual damage to the bearings.

 

[PilotRudy]

Thats not how this work, that tune explicitly states it only supports the cobb intake. The following is why this is important and was recently posted AGAIN by zax

Calm your tits buddy. If you’ve been working on cars long enough you’d know that not everything goes as planned so you often need to improvise. In this case it works

 

[stilletto]

Calm your tits buddy. If you’ve been working on cars long enough you’d know that not everything goes as planned so you often need to improvise. In this case it works

It may work for the time being but that tune was not designed around that particular intake. Both Cobb and MAP stress this often.


Sent from my iPhone using Tapatalk Pro

 

[zax]

OooooOoooo I can tell you are going to be fun to play with.

You start with this, posted in response to a volunteer attempting to help YOU with YOUR problem. He has no obligation to help you. He isn't being paid for his time.

Calm your tits buddy.

This gets good. Then you say

If you’ve been working on cars long enough you’d know that not everything goes as planned so you often need to improvise.

Which appears to be an attempt to flex some type of credibility by claiming that you've worked on cars "long enough" to understand intricacies by providing some extremely weak anecdotal evidence:

In this case it works

OK cool. Define "works." It's evident that you don't understand what the ECU is doing so how do you know that you didn't make things a whole lot worse?

Time for some education. If you really did have the experience based on your claim above, you'd understand what this graph indicates comparing Cobb's two maps (one for stock intake, one for SF intake). This is for an EJ, mind you so YMMV.

This graph shows an increasing airflow calculation error by using one map with the other intake.

Yeah yeah I get it... this is the world we live in today. Feelings are more important than facts. I guess we have all just decided that facts are no longer relevant. It's very apparent this is an overall trend that even Cobb has to contend with as they plaster these warnings all over their pages:

But hey... what's the point in wasting your time reading when you've "been working on cars long enough."

I don't work for Cobb, but I'm reasonably certain that the Perrin Intake isn't a Cobb Tuning Big SF intake and Airbox system. Ergo that map isn't designed for that intake and yeah... since the big SF intake flows more air per cross-sectional area, your ECU is improperly adding LESS air than it thinks causing mixtures to run overly rich. Hopefully the O2 sensor is doing its job to pull the mixtures back within normal values. I'd love to hear your excuses 9 months from now when your rings are worn down from cylinder wash and your cats are damaged from the overly rich mixtures.

I'm sorry, are any of these facts getting in the way of your feelings?

 

[XJman]

Calm your tits buddy. If you’ve been working on cars long enough you’d know that not everything goes as planned so you often need to improvise. In this case it works

I guess when you don't know what's going on or what "works" is you can just claim anything. I guess you can just change the meaning of the target word in this case.

 

[WRX-maniac]

I guess when you don't know what's going on or what "works" is you can just claim anything. I guess you can just change the meaning of the target word in this case.

LOOK, as long as the car starts and drives its FINE...… right?..... right? Seems to be the logic for a lot of people. Lol