Stock air intake duct

[wytbishop]

I liked those links alot. I definitely learned some stuff.

The Bernoulli equation allusion you're making with the straw ananlogy has, I think, totally different implications in the IM runners than it does in the intake filter tubing. I even think that the information in the links you provided supports me in that. Clearly, once the plenum is filled with air and slightly pressurized the diameter of the IM runners will have a significant impact on the velocity of the air/fuel mix moving into the ports but a change in size of the intake duct, which is influenced by harmonics and resonance to a much lesser degree, will have a much lesser effect, I think. Changing external components, perhaps including the TB, will certainly affect the pressure in the plenum and at what rpm peak pressure is achieved, however, I don't think the actual quantity of torque produced by the engine will be affected significantly. I think this is why we see such small gains when installing CAI systems. We get a little bit more air and that's about all. I maintain that the change in diameter of the tube and resulting loss of velocity head is overbalanced by the reduction in minor and major losses.

And, while I understand that obviously the length of the CAI tubing will have an impact on the position of peak torque, I think that there are other mechanical considerations such as available space and the location of the cold air that will dictate the length of the pipe. I do think that people reading this: "You add 1.7 in. for every 1000 rpm that you want to move the peak torque below 6000", should realize that if they decide to route a CAI through the front bumper cover or something to try to get the really cold air (something I can imagine a person might think is a good idea), that they'll have a negative impact on performance because the peak torque will occur at 0rpm and immediately start to fall.

Clearly others are more well versed in the fluid mechanics specific to engines and intake systems than I am. I never claimed to have all the answers, but I like to try to do my own thinking.

I enjoy these kinds of discussions very much. I hope you don't think that we're arguing. I'm not trying to be a jerk or imply that I know everything and you don't. I'm just a geek who gets off on physics.

[shameem]

I enjoy these kinds of discussions very much. I hope you don't think that we're arguing. I'm not trying to be a jerk or imply that I know everything and you don't. I'm just a geek who gets off on physics.

same here.....

[Leedeth]

Would I see any gains at all if I remove the duct so that the air is sucked directly into the airbox, or is it too close to the radiator? I think it would free up flow a bit since it's a real small hole at the end.

I'm not looking into a CAI or anything, it's not worth it on a B6. I just want to see if I can squeeze out a bit more power with what I have.

[SmoothMX3]

Im thinking you have the 4cyl. mx3?
sorry, I dont know the names for them yet.

Anyways, When i used to own a 4cyl mx3 I installed a CAI and a 2 1/4 custom catback exhaust. To be honest, no I didnt feel any gains off the intake with my butt-dyno. Yet, my brain was giving off signals that i got about 3 or 4 horsepower. The exhaust felt the same, yet i really believe it made my car faster. I dont think it gave me any horsepower, yet i do believe it free'd up loss of horsepower. got me?

What you have to look at is, putting this intake on may help and may not. Leave the intake along and just install an exhaust, it may help and may not. Add them together and they can work with each other. them small things add up.
Let me ask you this, do you really know what 10 more horsepower feels like? just 10 more horsepower? ... It's a big difference. For example, throw in a chip (superchip) and feel the gain. then take it out and see the difference. my point, just adding this intake might not give horsepower but when adding all these mods together you may get horsepower from that intake.

sorry guys, i suck at explaining myself. hope you somewhat get it. lol

[Leedeth]

Im thinking you have the 4cyl. mx3?
sorry, I dont know the names for them yet.l

Yeah, the RS has the B6-ME from 1992-1993, and the B6-D 1994+.

[wytbishop]

Im thinking you have the 4cyl. mx3?
sorry, I dont know the names for them yet.

Anyways, When i used to own a 4cyl mx3 I installed a CAI and a 2 1/4 custom catback exhaust. To be honest, no I didnt feel any gains off the intake with my butt-dyno. Yet, my brain was giving off signals that i got about 3 or 4 horsepower. The exhaust felt the same, yet i really believe it made my car faster. I dont think it gave me any horsepower, yet i do believe it free'd up loss of horsepower. got me?

What you have to look at is, putting this intake on may help and may not. Leave the intake along and just install an exhaust, it may help and may not. Add them together and they can work with each other. them small things add up.
Let me ask you this, do you really know what 10 more horsepower feels like? just 10 more horsepower? ... It's a big difference. For example, throw in a chip (superchip) and feel the gain. then take it out and see the difference. my point, just adding this intake might not give horsepower but when adding all these mods together you may get horsepower from that intake.

sorry guys, i suck at explaining myself. hope you somewhat get it. lol

That's called "Synergy". When the affect of adding two things together is greater than their sum. For example, an exhaust alone might give you a couple hp and the CAI might give you one or two, but because they work together to make each other more effective, the addition of both might give you 7-10hp overall...or at least FEEL like 7-10.

Definitely, doing things like exhaust and intake mods together with some careful thought will give better results than doing them one by one without considering the potential combination.

[SmoothMX3]

Thank you.. haha

You seem to explain things better then a dumb guy like me. lol
Such big words.

[Aston Wards]

Would I see any gains at all if I remove the duct so that the air is sucked directly into the airbox, or is it too close to the radiator? I think it would free up flow a bit since it's a real small hole at the end.

You would think so wouldn't you? unfortunately things aren't quite that simple.

The only time you'd benefit from the extra flow would be at the top end of the rev range, and only then if the stock ducting was actually restricting airflow..., the rest of the time you would probably be losing out due to decreased flow speed.

Mazda spent a lot more time and money on this than we could ever afford, sure they had other considerations, but you'd be an idiot to discount their ideas totally.

[somorecords]

(please bare with my bad spelling) i can agree with allot of what some of u are saying but, i see a reoccuring phrase "your not gaining horsepower your gaining throttle response" and my response to this is that whats wrong with this? their are considerations other than horsepower and torque. And you cant learn everything about a car by its dyno run. Throttle response is just as important as a million other non dyno considerations that effect performance of a vehicle, from aerodynamics to shift times. however my thinking may be twisted in the importance of throttle response becouse of my expeirience with older vehicles (older as in pre 1979) where throttle response is a major problem with carbruated engines. in short i felt that the gain in throttle response in my MX-3 was well worth the 60 bucks i spent on my CAI. i know im new and im not tryna act like i know it all but just my opinion

[SmoothMX3]

Well that's kinda a question you would have to ask your self ...
Is it worth giving up maybe, 1 or 2 horsepower to gain better throttle response?
I totally agree with you. I hate lag. Maybe it's just my mx3, But mine has a bit of lag in the throttle response. Which i just came from a car that had almost no lag.
I'd love to clean up the powerband on this k8. It's at about 3500rpm in 3rd.

[wytbishop]

(please bare with my bad spelling) i can agree with allot of what some of u are saying but, i see a reoccuring phrase "your not gaining horsepower your gaining throttle response" and my response to this is that whats wrong with this? their are considerations other than horsepower and torque. And you cant learn everything about a car by its dyno run. Throttle response is just as important as a million other non dyno considerations that effect performance of a vehicle, from aerodynamics to shift times. however my thinking may be twisted in the importance of throttle response becouse of my expeirience with older vehicles (older as in pre 1979) where throttle response is a major problem with carbruated engines. in short i felt that the gain in throttle response in my MX-3 was well worth the 60 bucks i spent on my CAI. i know im new and im not tryna act like i know it all but just my opinion

I totally agree that improved throttle response and tuning for peak torque are very important. Horsepower is expensive. You can't always afford to spend alot of dough to gat an extra 50 or 60 hp, but most people can afford <$100 for a good intake and tuning. The original question posed in the thread was "...does it act like a (restricted) CAI? Because, it runs from the filter box and out to just under the front of the hood." I was only trying to show that the actual power and torque gains from these kinds of mods are minimal and why. My initial response was to try to explain that the stock intake system is actually pretty good, which is evidensed by this fact. Aston's post actually brought the whole thing back to that point very nicely.

The rest of this thread is really just a form of science geek masturbation. On my part as well as others.