My custom KN intake mod

C

czechT698

Active member
 Prague
:) Well, I wanted a better intake that works and didn´t cost too much money. So me and my cousin put our heads together and got down to bussiness.
We installed a KN conical intake to replace the stock airbox. We understood the effect of the ram-air stock intake so we ran an aluminium semi-flex hose all the way from the KN filter into the front of the buper where we created a custom made (fiberglass) RPI intake scoop. Here are the pictures:

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I did test runs in rainy conditions and water is not an issue anymore. as for the performance - couldn´t be more happy. More growl, beter acceleration a higher speeds. Reaching the 250kmh speed limiter in not that hard anymore. (Not that I tried.... 8) :oops: :evil: )

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Video here:

 
Nice.

Try to fab a bulkhead to keep any of the hotter air from the engine compartment getting to the inlet. Unless you have it partitioned off, you will get hot air in the intake and it will reduce your power output.
 
Shipkiller, well to be honest it could have been done, but we got so drunk that we had to take a pause because the probability of fu**ing it up increased big time :D
 
Shipkiller said:
Try to fab a bulkhead to keep any of the hotter air from the engine compartment getting to the inlet. Unless you have it partitioned off, you will get hot air in the intake and it will reduce your power output.
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+1. What the OP has is another example of HOT AIR INTAKE, and more importantly losing the ram-air effect at the same time.

Honestly if I were the OP, I'd put the stock intake back in the car. With your set-up righ tnow, air is only entering from ONE SIDE of the filter. With a cone filter, you take advantage of it by putting it in a pressurized box so air can enter it from ALL sides of it from all the angles. Even if you put a simple shield over it, if it's not sealed you're still not getting the ram-air effect which essentially acts like a mini supercharger the faster you go. The stock air-box is very well designed. The K&N is about as generic as it gets; they make filters for every single car out there and spend little time doing R&D on each car. An exposed cone filter like that makes sense for some cars because their factory air box is so crappy that anything else would be an upgrade. But still the design itself makes no sense. And on a BMW it'll definitely sound nicer and lose you power at the same time.
 
I'm with GP20 on this one :thumbsdown: . Although you report improved performance, I'm surprised. The benefit you are getting of the scoop is lost as it's just pushing the air in the direction of the filter, not pressurising it. Each time you slow it will just pool red hot air around the filter and reduce off the line perfornmance.

I'm sure you get more induction noise so it may sound different, but think you need to modify this a bit more.
 
cj10jeeper, yes, I do understand the concept of the stock intake, what I wanted is more boost at higher speeds as well as more growl and this setup is the perfect satisfaction. I mean, here in CZ, you either drive 50kmh in town (no need for HP), 90kmh on a normal road (nothing special) and on the highways 130+ (no one respects the speed limits on the highways). My highway speeds are usually 160kmh+ and even though I lost the Ram-air effect, there is an incredible amount of cold air getting through the intake, combined with the KN filter the air jumps straight into the engine resulting in a noticable boost when I floor it at 120. I might have lost some power in lower speeds but there is a noticable gain when going fast, the gain could have been better with the stock intake with a KN panel filter in place, but well, cool mod anyways :P
 
You'd have gotten a better 'boost' if you'd simply kept the original airbox and simply attached the ram-scoop into that á la the Race Precision (RPI) one. Then you'd have less hot air from the engine going in at high speeds - don't forget that all that air that is sucked up into the engine bay at high speeds goes around the engine and will still be sucked in by your filter.

The standard airbox is also probably tuned to match the engine's characteristics, so you may have in fact lost power elsewhere and the 'boost' you're feeling is when you actually get normal power back rather than 'extra' power.

You've also got to take into account the amount of smooth airflow that you've disrupted by using corrogated tubing - you may have actually REDUCED the cold air going into the engine!

You're probably now only providing 10% cold air to the filter plus 90% hot air - even if it is faster - compared to 90% cold and 10% hot on the standard box.

However, if you feel it's better for you then keep it and ignore any comments you get on here :evil:
 
czechT698
Hey - if you're happy with it cool, just not the sort of setup that does it for me. I'd keep the nice scoop you've crafted and put back the box along with a new OEM or free flowing aftermarket filter. However since you want indiction noise then it probably does it. You could also add the sound generatotor from a 3.0i (if you don't alreafdy have one.
 
czechT698 said:
cj10jeeper, yes, I do understand the concept of the stock intake, what I wanted is more boost at higher speeds as well as more growl and this setup is the perfect satisfaction. I mean, here in CZ, you either drive 50kmh in town (no need for HP), 90kmh on a normal road (nothing special) and on the highways 130+ (no one respects the speed limits on the highways). My highway speeds are usually 160kmh+ and even though I lost the Ram-air effect, there is an incredible amount of cold air getting through the intake, combined with the KN filter the air jumps straight into the engine resulting in a noticable boost when I floor it at 120. I might have lost some power in lower speeds but there is a noticable gain when going fast, the gain could have been better with the stock intake with a KN panel filter in place, but well, cool mod anyways :P
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No you don't understand the concept of ram-air effect. Especially at higher speeds. Because if you do you would've preferred the stock air box. And like I've said, even if you want to retain the cone filter, it's set-up and angled the wrong way.

How many more people other than me, c10jeeper and mmm-five will it take to convince you that you have an inferior set-up than stock - under all driving circumstances (city, freeway, etc)?
 
pmeloche said:
What a waste of time, money, and effort.
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Don't think it is a waste of time and effort and very little money seems to have gone it to it..

Think of it as a learning experience and just wanting to tinker....
 
i gotta give this guy credit for doin' something different. props with the setup. it could use some work.. but it's a step in the right direction. keep us posted on this thread on the performance your new intake is giving you. i know i'm curious about it~
 
You want to get a manometer and test the pressure difference just after the air filter before/after the mod.

I can't see from here, but if you have a 3.0, the sound generator will give you the noise you want, while also leaving the highly efficient standard intake system in place!

An open under-bonnet filter like that will be worse in every possible way :(

http://autospeed.com.au/cms/A_0629/article.html

Dave
 
Now that's something that's beautifully done and seems well engineered.

What kind of intake is it?
 
It's made by a company called RamAir - It's genuine carbon fibre and the bracket kit is very well made as you said...
i got it off ebay a while back, really good piece of kit!
 
Interesting stuff.

However, on these ram air contraptions how do you stop water getting into the filter? Obvioulsy when its raining and the car is travelling forward water will enter the pipe and travel along it until reaching the filter.

How is this prevented as too much of a filter at the entrance to the pipe will restrict air supply.......?
 
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