So, ecuflash does not have maf scaling, but the AP does? What about ecutek? I have seen the tables in ecuflash, and it's definitely capable of tuning the A/F ratios, so what's the difference between this and maf scaling? Are there two different aspects of tuning the A/F ratios? Also, I agree that when using an intake or drop in filter that part of the gain is from decreasing pumping losses, but they all seem to show leaner a/f ratios as well. If the maf sees more airflow, then isn't the ecu programmed to add fuel to maintain the A/F ratios as per the maf scaling tables or whatever takes care of that? I'm confused why the A/F ratios are leaned out in spite of this. Do you have any insight into this? I would really appreciate an explanation, because I'm driving myself crazy trying to wrap my mind around this. Thanks.

 

Can you please provide links to the tests that show this?

 

So an inlet hose like cobb or perrin make wouldn't really make a difference once tuned?

 

That would seem to be the opinion of a couple people that have posted here. I have yet to see a test that has been conducted that has supported that conclusion.

 

Maybe not in overall peak HP, but in a lot of dyno charts ive seen it helps with spool up.

 

EcuFlash has maf scaling tables on 8/9 and will have it on the 10.

 

Which intake systems available now for Evo X have larger MAF housing and which ones have stock MAF housing?

 

Here's a list of companies that change the MAF housing.

AMS
AGP
HKS (only for 5MT)
AEM
Ultimate Racing
Agency Power

Companies that use spacers to move the MAF to get the same effect as enlarging the MAF housing:
Blitz
Gruppe M

 

By "change" you mean swap the actual part and increase the internal diameter, right?

 

Most, if not all, have increased diameter. You'll have to confirm this with the manufacture to get the actual size since they usually do not advertise it.

 

The ZChip can also be used to rescale the load, instead of using a larger MAF housing that will affect not only high load, but low load also. You can set the start and finish of what high load section that you would like to rescale while leaving low load perfectly stock.

 

Thanks for the info, but what about the other part of my question? No one seems to be able to answer this for some reason. Maybe no one knows?

 

very rarely is the filter the most restrictive part in an intake system, believe it or not. For Example, a stock OEM honda S2000 filter actually flows more than the K&N replacement.

Bends, and large ribbing for flexibility in rubber parts, ect.. are what need to be removed.

 

(quote from sti2evox:
So, ecuflash does not have maf scaling, but the AP does? What about ecutek? I have seen the tables in ecuflash, and it's definitely capable of tuning the A/F ratios, so what's the difference between this and maf scaling? Are there two different aspects of tuning the A/F ratios? Also, I agree that when using an intake or drop in filter that part of the gain is from decreasing pumping losses, but they all seem to show leaner a/f ratios as well. If the maf sees more airflow, then isn't the ecu programmed to add fuel to maintain the A/F ratios as per the maf scaling tables or whatever takes care of that? I'm confused why the A/F ratios are leaned out in spite of this. Do you have any insight into this?"

ECUflash does have MAF scaling for the EVO 8-9's. I personally have not seen anyone tune the car using it without also using the AFR tables to further adjust the fuel. I could be wrong but the maps I have seen from various tuners do not use the MAF scaling to solely adjust AFR's.

The ECU doesn't adjust AFR's at WOT, WOT is in open loop and the ECU doesn't use 02 feedback in open loop, only in closed loop. This is also the case on cold start, the ECU doesn't use the 02 sensor on initial start up, it runs off a pre-determined map. This is why much of what TTP and I are trying to explain is important. The MAF does add more fuel in closed loop, that is why you see people talk about the STFT, LTFT's. If the tune is way off from a MAF that isn't calibrated correctly or the injectors are too large the car will throw a CEL for the being too rich/lean or a variety of other codes. The car will add/subtract fuel in closed loop based on the 02 feedback but if the amount of feedback is more than the allowable difference you get the CEL.

 

You need to have a 2D MAF voltage vs. load table and an AFR table (in load vs. RPM).

Reason why…

This is all hypothetical and the numbers are no where near realistic.

Example 1a.

Lets say on a stock car, in the 2D table at a 3V of MAF voltage you have 200g/s of air going by the MAF. So now in your AFR table at 4000RPM and 200g/s you have 11:1 AFR inputted there. Everything is great, car runs well no problem.


Example 1b.

Now lets put a larger diameter MAF housing on the car. No other changes.

We still have the same amount of air going into the motor as with the stock housing but because of this larger diameter housing, our MAF voltage is now 2.5V, which is 150g/s. Go back to the AFR table and at 4000RPM and 150g/s we have 12:1 AFR inputted there. All of the sudden we are now running lean at peak torque…things go boom then.

Example 1c.

Lets leave the larger diameter MAF housing on the car. But let’s go into the 2D table and adjust our MAF calibrations for the larger MAF housing. We now know that at 2.5V of MAF voltage, our airflow is really 200g/s, not 150g/s. So we bump that number up to 200g/s. Now when the ECU sees 2.5V at 4000RPM, it goes to the 4000RPM/200g/s load site in the AFR table, which is 11:1 AFR and all is good again.


This all makes sense in my head but after trying to type this answer out, I think I didn't do so well.