You are misreading Smog's mod list I believe. Stck intake manifold.

All the pics I've seen of Smog's setup showed neither stock inlet tube or box. When he posted about his MAF screen failing, the pics showed a MAF adapter that replaced the stock box and allowed an open element filter

 

My buddy brought over used ARC intake for his EVO 8. We were dying to find out how it works. So, we installed it and try to tune it using UTEC. While boost was building a little faster, we could not reduce the knock around mid-range.. When, it was hitting max boost around 3.5K, we were seeing as many as 40 knock counts... We loved added responsiveness and cool noise it added but decided to take it off and consult prof. tuners...

So, I know there is definately a room for improvement. I also know that MAF system with aftermarket intake can be tricky to tune for average people....

He finally had turbotrix tune his car with ARC intake and other turbo upgrade... (reflashed ECU and got rid of UTEC)... Car runs absolutely perfect while responsiveness is improved.... Best of all, I love the stock BOV/DV sounds.. Pshhshshshs who needs after market BOV anyway!!!

 

I've measured about 1.4 psi pressure drop at the MAF at 7000 rpm with a completely stock airbox and Works drop-in airfilter. I'm looking forward to cutting my airbox lid like jscbanks did to see what happens with the pressure drop. I figure if it drops 1 psi, that means the turbo will not be working quite as hard and should net a slight increase in efficiency.

 

1.4 PSI gain in removing a restriction could easilly be over 10WHP gain.

 

I switched from my stock airbox with K&N drop in to an HKS SMF (filter and adapter only). I gained 1 psi of boost pressure on wastegate actuator pressure alone. When I switched on the EBC using the same settings, the taper was reduced up to also. Both setups used my HKS MAF Hardpipe. My results concor with the results that mrfred found. The airbox is definitely a restriciton over a conical filter system. I dont believe the MAF itself is much of a restriction at all.

 

make sure you choose an intake filter desigend to be run with a MAF.

I know of only two

Apexi and Buschur's.

 

I am pretty sure the ARC box is for the MAF too. Check dis out:


https://www.evolutionm.net/forums/sh...d.php?t=252487

 

Yeah that ARC box sure is nice and I am sure it flows more then the OEM box. I just bought a APEXi intake filter and am now currently looking for an APEXi Induction Box.

 

Yep that is common sense...for anyone that keeps the fundamentals for how a car works in mind.

 

Just to clarify, on my 585whp/527wtq dynojet pull, I had the stock maf, but used the AMS intake:



Dang, my engine bay was sexy! AMS uses this pic on their website to sell their sparkplug covers.

 

Runs 10 and 11 are from my old days during an MS109 tune: Shiv was doing the tuning. The two pulls were taken only 3 minutes apart on the dyno and no tuning adjustments were made. I was running the stock airbox, stock filter, and stock maf. On run 11 we took the airbox cover off AND took the filter out and did a pull just for fun. With no filter at all and the top off the airbox off we only made 2 more horsepower and the same torque.

I would say however, that run 11 (no filter run) looks a little better over 7200rpms. I'm not trying to argue any specific point, but these particular pulls indicate that the stock filter isn't a significant restriction at 370whp.

 

having run speed density with hard pipe and an ITG filter and then having gone back to stock intake I would say the biggest difference was the quality of engine sound.
The hard pipe acts like a horn transmitting the turbo noise. Not particularly indicative of power imho.

Of course I can't comment on power gains or losses, for a number of reasons, the least of which is how do you justify the tuning necessary to run for each system being equal. iow pretty hard to develop a tune for a system in a matter of a few minutes.
let me just add, as an indication of my position, my aftermarket ems with restriction less intake did not offer any perceptible power gain over my switch back to stock intake without ems. In fact the loss of the turbo horn sound makes me feel 23.113% better.

 

This compare was conducted ~2 hours from each other, on the same day,same fuel, similar ambient conditions, same stretch of road, same mbc settings.

These are results that i experienced. Your results may vary.

However, there isnt too many post's illustrating their results with logged data.

It's either "yeah, it felt better", "yeah it's louder" WHICH IT IS or "nah, i didnt feel any difference"

All what i can say is, the dyno numbers posted below speak for themselves.....The dyno numbers were achieved on california's finest 91 octane

smoggies numbers look to be run on MS109? is that vp 109?

This post just illustrates the potential for maximizing what you have....a oem based turbo & readily available bolt-on goodies

The dyno plots are illustrated within the 65mm tb dyno compare below.

 

of course vp ms109

 

I don't have dyno numbers to prove that getting rid of the MAF is a significant HP gain but I will have track times come the first of april....only changes were switching from stock edu to the AEM, converting to speed density, and going from 660cc to 1000cc injectors.