Sometimes it's the little things holding you back.

[david buschur]

This is about an EVO I have at our shop right now but I thought worthy of posting here as it is important to any build.

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This one is nuts. This is basically a Stage 2.5 EVO9. So stock engine/head/cams/turbo/intake/throttle body all stock.

The car came here with our turbo back, our upper i/c pipe, AMS FMIC, AMS MBC, AMS MAF pipe with a K&N open filter on the MAF, stock EVO9 BOV. The car made mid 340 whp on 100 octane at 26.5 psi of boost.

The customer is looking for 370 whp. I felt it was possible with the addition of our 02 housing and a better BOV. So we added our 02 housing and the Synapse BOV. Put it back on the dyno and power was 350 whp/334 ft lbs. I tried turning the boost up and it just didn't want to make any more boost. I then swapped to our MBC as the AMS brass thingy was all the way tight. Our MBC made no more boost either. Very odd.

I stood and stared at the engine for a few minutes wondering what was going on. Then I noticed the K&N was rather beat up, dirty and looked small. I figured "What the hell, something is holding it back." I went and got our filter and was going just swap it in place but it wouldn't fit. Our filter was substantially larger than the K&N and wouldn't fit because of the ACD. I pulled the MAF pipe off and replaced it with our single bend MAF and then put our filter on. Jumped back in the car and with ABSOLUTELY no other changes the above dyno graph was produced. As you can see it went WAY lean and the boost went up. I fixed the fuel map, added some fuel and ended up at the same whp/torque level as above with the AFR's in the 11.8:1 range.

This is just incredible to me and goes to show how important the "little stuff" truly is.

We are talking a 16 whp and 19 ft lbs increase in power just from changing the MAF and filter!

 

[marcman804]

Wow, this really makes me want to upgrade my MAF and changing out my K&N filter.

 

[silicosys4]

Wow. Time for you to make those big air filters for dsm's, so we can join in the fun too. Quit teasing !!

 

[JusMX141]

Remarkable for sure, Dave.

If I recall, at the Shootout a few years ago my buddy Ben's completely-stock Evo X made something like 256whp on your dyno with nothing more than an air filter upgrade. Stock exhaust, stock 152G6 turbo at the stock boost level. At the time you had claimed it was the highest stock Evo HP ever achieved on your dyno and kept asking Ben what else he had done to the car.

Sadly, that Evo eventually started suffering some engine problems which were luckily covered under warranty, but the car went downhill rapidly due to a dealer that apparently didn't know what they were doing. I remember him getting the car back from the dealer on one occasion and you could clearly hear an exhaust leak in the engine bay- either the manifold or turbo gasket. Little details that the dealer constantly overlooked and Ben just got tired of screwing with it.

Maybe there's more than meets the eye with air filter tech!

 

[goodbye]

It's amazing how many cars I've seen in recent years with cheap-ass ebay air filters, such a simple concept that's lost on a lot of people over a few bucks.

 

[shockey1013]

This is a good write up. Especially for people who are new to the build it, boost it, break it world ha. But for real thanks for the good information.

 

[Dyesuperman]

Wow that's impressive, I may have to swap out my spectre filter for a legit K&N

 

[doubled07]

Air and fuel are what make power. Gotta have enough of both. Curt Brown did a lot of testing and uses Green Filter's. Must be a reason for it!
Just the little things that matter sometimes....good post thanks Dave!

 

[habitatguy187]

http://www.dsmtuners.com/forums/bolt-tech/153744-air-filter-pressure-drop-results.html

 

[Jon91TSi]

That's exactly why I'm rocking the big guy... Lots of surface area!!

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[agarc023]

Wow... I should probably clean my k&n up then

 

[david buschur]

The filter that WAS ON THE CAR and causing the issue was a K&N actually. It was simply too small, dirty and kind of beat up/crushed in places.

We have also done a lot of air filter testing, hell we've done a lot of testing on everything when you get down to it. 1,000+ dyno pulls on my own EVO, that's a lot of testing.

We use Green Filters too, actually they custom built all our Forward Facing turbo kit filters. I believe one of the key components to a good filter are an open end on them, not a capped end. The filter we use on the EVO's and in this test utilizes the funnel entry on the end, as does our Green Filters for our Forward Facing kit. The filter we use on our FF kit is actually fairly small but I easily make over 700 whp through it and gain nothing by taking it off on the dyno.

 

[Dyesuperman]

What are the Green Filters?

 

[doubled07]

Green Filter is the name of the company. Here's a link to all the cone filters they offer. Cone Filters
700 HP with or without a filter is a good testament...haha. 700 hp is just awesome period! Nice thing about their filters vs kn or anyone else. For our cars especially. The filter has a steel mesh instead of aluminum like the other guys. It won't collapse on large turbo / high boost cars. Bunch of my buddies run them on their diesel trucks also.