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Performance, Brainstorming & Tuning Talk about modifications, or anything else associated with performance enhancements. Have a new idea for performance/reliability? Post it here. No idea is stupid! (please use Detailing and Appearance for cosmetic ideas)

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Old 08-27-2005, 01:02 PM   #11
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An intake will benefit a NA better in the laminar flow department than total flow. I don't think a mostly stock L27 can outflow a stock filter, or an L36 for that matter.

Headers would do you better than PEM'*, but PEM'* are cheaper and easier to install, and are probably 75% as effective?

I'd trust INTENSE on the stock mufflers on 8-ball any day over theory. Those guys know what they're doing.

Not sure how you plan on a single muffler to replace your duals on a 2k+? Or am I misunderstanding?

Don't do the Cat until you decide what to do with the rest.
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Old 08-27-2005, 06:47 PM   #12
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you want as little back pressure as possible. whoever says loosing back pressure kills torque is wrong, you dont want backpressure. the problem is, people put bigger pipe to reduce back pressure, which kills VELOCITY. its when you reduce your exhaust velocity (big pipe) that you loose torque. scavenging has nothing to do with the cat back, ONLY has to do with headers/exhaust manifolds. the exaust comming out of one header tube can actually help to create a vacuum to "suck" the exhaust out of the next tube, adding velocity (torque) which is why its very difficult to make GOOD headers, theres a ton of engineering that goes into headers to do this. this is why a ported exhaust manifold will never be as good as a properly designed header, they can come close to cheap headers

and a big air filter is as bad as big pipe on your exhaust, for the same reason, velocity. if you think of it as a vacumm, put a 4" extension on the end of your shop vac, and try to suck stuff up, its not nearly as effective as the same vacuum with a 3", you have to find the balance


2.5" is overkill for a 93 se that makes about 170hp. you'd be better off with 2.25" and a strait through muffler. mufflers like flowmaster sound pretty good, but they are not a performance muffler, they have baffles which deystroy airflow/velocity, but are "tuned" for a good sound.
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Old 08-28-2005, 12:59 AM   #13
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A big air filter is a good thing. Reducing intake restriction is a completely different animal than the exhaust. The filter doesn't have any direct bearing on velocity (unless it is too small for the engines needs), the gradual reducing of the piping leading into the actual engine is where the velocity increases, giving a slight ram effect. The shop vac. analogy would be an easy test. Pull air through the stock filter box and filter and try it again with a cone filter of larger area in place of the air box. A shop vac., even a big one, doesn't really have the power of the actual engine air intake at full throttle, but it will flow more air with a larger filter.
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Old 08-28-2005, 06:45 PM   #14
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I have to agree that a large air filter will not hurt performance. The density of the air would be most important. I am starting to rethink the flowmaster and go with magnaflow. Just not sure if I will get a good sound from it. I don't want a rice burner sound. Anyone heard a magnaflow on a 3800?
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Old 08-28-2005, 07:02 PM   #15
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there are a bunch of Maggys and Flow'* on here
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Old 09-06-2005, 08:23 PM   #16
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Quote:
Originally Posted by 2seater
A big air filter is a good thing. Reducing intake restriction is a completely different animal than the exhaust. The filter doesn't have any direct bearing on velocity (unless it is too small for the engines needs), the gradual reducing of the piping leading into the actual engine is where the velocity increases, giving a slight ram effect. The shop vac. analogy would be an easy test. Pull air through the stock filter box and filter and try it again with a cone filter of larger area in place of the air box. A shop vac., even a big one, doesn't really have the power of the actual engine air intake at full throttle, but it will flow more air with a larger filter.

sorry but your theory is 100% wrong

yes a big air filter will flow more, as big exhaust will flow more. both are related. a 3" exhaust will flow more than a 2.5", but it will slow your car down (asumming were not talking heavily modified cars) as will a 9" cone on a ssei (not HEAVILY modded) a series II would do best with a 5" tops, 7" for the ssei'*. matching the proper cone size to the engine and manytimes reducing filter size has proven many many times on dyno'* to increase power, especially torque

ive seen dyno'* showing cars LOOSE power with a cone filter. (high quality piping, filter - big old filter) that same car, with a smaller filter (5" on a stock ls1) and same underhood temps picked up alot of power

big filter theory falls in the same category as big exhaust theory - all its good for is bragging to the kid at autozone about it
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Old 09-06-2005, 10:58 PM   #17
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There is no doubt there is a point of diminishing returns although I would like to see dyno results that indicate when too much on the intake side is a bad thing. Even an N/A engine operates on pressure differential, between atmospheric and the vacuum formed in intake. I cannot prove this is true until I test the theory on the flow bench.
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