|06-05-2008, 08:41 PM||#1|
Drives: X1, 335i
Join Date: Sep 2006
Location: SF Bay, CA
NEW: Vishnu Dual Filter Intake $195
One of the things that surprised us about this market is that after nearly two years, there is no proper intake system available for the 135/335/535. By proper, I mean one that provides ALL of the following:
1) Separated and symmetrical airflow to both turbochargers (no restriction bias)
2) Low pressure loss in high power application (sufficient filtration area)
3) Good fitment (doesn't rub against important stuff under the hood)
4) Durability (flanges don't tear)
So.... we made one. Here are some pics:
The stock airbox is restrictive at power levels much greater than 340whp (Dynojet). This does not mean that it cannot support more power. It just means that vacuum develops at the turbo inlet and the turbos need to spin harder than they need to. This generates more heat and exhaust backpressure do to the higher pressure ratio. By eliminating this vacuum, the turbos are relieved of unnecessary strain and can make more power with less heat and exhaust backpressure. Need proof? It's coming later in this post.
What is "wrong" with the factory airbox?
At stock power levels, there is absolutely nothing wrong with the stock airbox. It flows enough air with minimal restriction. But at higher-than-stock power levels/airflow, it is the N54's Achilles heel. And here's why:
Here's a picture of the factory airbox:
Here's how airflow must flow before it gets to the turbos:
Notice how the airflow gets restricted as it has to make the 180 deg bend just downstream of the air filter. This is the major sources of restriction with the factory airbox. This is also why drop-in air filter upgrades are only worth a few horsepower and not the 15-25whp we often see with our high flow Dual Intake System!
The other source of restriction is the air filter itself (next to one of our filters):
The factory filter only has approx 90 square inches of surface area. This is insufficient for the 340+whp the PROcede is easily capable of supporting. Each one of our filters offers nearly 100 square inches of surface area! With 2 filters in the system, total surface are is over twice that of stock! This might sound like overkill but it isn't. Imagine what happens when the filters accumulate dirt and effective flow rate gets compromised. Even when handicapped with dirt, our Dual Intake System is easily capable of supporting up to 450whp worth of airflow. And making the job of the turbocharger as easy possible while doing so.
Here's the inside of one of our air filters:
Notice the inverted cone design implemented inside the filter to smoothen airflow as it enters the intake tube leading to the turbocharger inlet. Just one of the little features implemented to reduce restriction and airflow turbulence.
What about cold air ducting?
The truth behind the matter is that lack of restriction is far more important than "cold air ducting". Especially in intercooled turbo systems. In such a system, the only temperature that matters is that of the air as it enters the intake manifold. But this air has already been on a long journey. It originally entered the system at the air filters. Then it travelled through the turbos, through a bunch of piping, then through the intercooler, through more piping and only then to the intake manifold. With the exception of when it passed through the intercooler, the air picked up heat at every stop. The largest heat gain occurred in the turbo during the compression stage. Here, air temps can easily rise by 150 deg F. A whole lot more than the 10-30 deg F gained from drawing air from under the hood (and not through a cold air box.)
With the vast majority of heat generated in the compression stage, it makes sense to address this stage and see what we can do to cool things down. First of all, we can actually reduce the amount of compression. And yes, we can do this without reducing boost pressure simply by eliminating the negative pressure (vacuum) at the turbocharger inlet. This reduces the pressure ratio which makes the turbo spin slower and generates less heat. And not only is there less heat generated through the reduction in compressor RPM, the amount of exhaust backpressure is also reduced. Add both effects together and you get a car that makes more power with less stress on the turbo. In fact, at 14-15psi of boost, our Dual Intake system offers a 15-25whp advantage over the stock cold air ducted airbox. And not only that, intake temps at the intake manifold is measurably cooler (that's what datalogging is for!).
Is it easy to install?
Yes. Total install time shouldn't take more than 15 minutes. Same goes for removal.
Will it make the car louder?
You will hear a bit more induction noise. But nothing obtrusive. Most people like the extra sound.
How much power will I make with it?
With our PROcede v3 running the standard map, on an otherwise stock car, expect to see 360-370whp on a dynojet. Assuming proper testing methods of course (good intercooler fans, reasonable ventilation, etc,.)
Ok. So how much does this cost?
$195 plus shipping.
Can I make the same thing for cheaper?
Of course you can! You could have also bought a DIY kit car instead of your BMW.
Is it available now for purchase now?
Yes it is. Only 50 kits in production right now. Will ship towards the end of next week. You can order on-line here:
|06-05-2008, 11:30 PM||#5|
Drives: Space Gray E90 M3
Join Date: Mar 2007
e90 M3, Space Gray / Extended Black, ZCP, ZCV, ZP2, DCT
sold: 2008 BS 135i 6MT
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