Any issues with an air filter messing with A/F ratios?
#8
According to works, their filter nets about a 15-18 hp increase of peak power, but at redline there is like a 38 hp increase due to leaning out the richest part of the power band, and due to the fact that boost tapers a little less. Now these gains are on a dyna pack, which is a much higher reading dyno than a dyno dynamics, but what I'm wondering about is the gains at redline more than peak increase. Noize, did you see a chunk of power like this at redline as well?
#9
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According to works, their filter nets about a 15-18 hp increase of peak power, but at redline there is like a 38 hp increase due to leaning out the richest part of the power band, and due to the fact that boost tapers a little less. Now these gains are on a dyna pack, which is a much higher reading dyno than a dyno dynamics, but what I'm wondering about is the gains at redline more than peak increase. Noize, did you see a chunk of power like this at redline as well?
My digicam is at home, but I will upload pics later to better explain what I am talking about.
I did the filter first, and the largest gain was like 8.5whp, right at 5000rpm. From 4800 to the rev limiter, it made at least 6whp globally, except for a couple of tiny spots.
Next, I put in a Hallman MBC. My car stock boosted to just over 21psi for an instant, then puked to 12.x psi at the rev limiter. The Hallman tapers substantially less. I set it to what stock boost is supposed to be (just at 23psi for an instant), and it tapers to 17psi at the limiter, just at 18psi at redline. This made this chunk of power for me that you are referring to, not the filter. Its actually quite silly, its making just under 240whp until 6800, where it shoots up to 260whp between 6800 and the rev limiter. It makes the car feel like an S2000.
My theory on this is that the car is still so rich that the engine is breaking up. There is not a hint of detonation, but until I can get control of the fueling, the car will not make power at all. I think with leaning it out and some timing tweaks, this car will pick up substantially. I have a Vishnu PROcede on my want list, and am waiting on the harness to come out. I have never seen a stock car that needs mapping as badly as this car does.
#13
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I have the Works filter and it seems to have cleaned up the top end. My car used to buck and jump sporatically at the top end. I think that's what Works showed on the Dyna Pak when they saw a 50 hp spike (negative) before redline. This dyno is extremely sensitive since there is not a lot of rotational mass masking transients (no drums turning, wheels, tires, etc.). I doubt if you could see the severity of these high RPM spikes on other dyno's.
The theory is that the stock filter/airbox system is the same as the regular Lance and is air flow restricting at high RPM's. Getting rid of this restriction is probably not a bad place to start the mod process.
The theory is that the stock filter/airbox system is the same as the regular Lance and is air flow restricting at high RPM's. Getting rid of this restriction is probably not a bad place to start the mod process.
#14
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I think that's what Works showed on the Dyna Pak when they saw a 50 hp spike (negative) before redline. This dyno is extremely sensitive since there is not a lot of rotational mass masking transients (no drums turning, wheels, tires, etc.). I doubt if you could see the severity of these high RPM spikes on other dyno's.
Last edited by razorlab; Mar 3, 2008 at 09:51 PM.
#15
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The filter helps lean out the AFR (although it's still plenty rich) and the "spike" in boost in the upper RPMs that we've seen on the dyno. Everyone we've heard back from confirms that it smooths out the high RPM hiccup that's encountered on the street. The following graphs represent baseline runs of a 100% stock EVO X and then the addition of the WORKS Air Filter and StealthWORKS muffler. So, it's not a filter alone, but the AFR and boost curves are representative of what we see by swapping filters back and forth.
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