Intakes

[bfi2906]

Could someone help me understand the merit of putting an intake on a car, please? I'm obvoiusly missing something.

As I understand them, and intake is intended to either deliver cooler air to the combustion chamber, or increase the volume of air delivered. Either will help create a more volatile combustion environment, and therefore more power.

What I struggle with is:
- On most / all BMW's the intake is in front of the radiator (on to actually), so it's already bringing in air from outside the engine bay, which will always be cooler than what's collected from inside the engine bay.

- On our TT cars, it's all irrelevant after the air's been through the turbos at 1000C (or whatever their operating temp is). It really doesn't matter whether the air's at 20C or 22C at intake.

- If it's an air volume issue, I thought that the "plumbing" on the intake side of the turbos was larger then the manifold side, so that's not the bottle-neck in the system.

So the only thing left is the air flow, which can probably be addressed with a pair of scoops and a better filter element, fitted to the standard set-up.

I'm sure there's a lot more to it than I understand, but I just don't understand why folks are spending money on DCI's and all kinds of other intakes.

Please feel free to correct my misunderstandings - that's what I'm hoping for.

Cheers.

[Taymaishu]

Originally Posted by bfi2906

Could someone help me understand the merit of putting an intake on a car, please? I'm obvoiusly missing something.

As I understand them, and intake is intended to either deliver cooler air to the combustion chamber, or increase the volume of air delivered. Either will help create a more volatile combustion environment, and therefore more power.

What I struggle with is:
- On most / all BMW's the intake is in front of the radiator (on to actually), so it's already bringing in air from outside the engine bay, which will always be cooler than what's collected from inside the engine bay.

- On our TT cars, it's all irrelevant after the air's been through the turbos at 1000C (or whatever their operating temp is). It really doesn't matter whether the air's at 20C or 22C at intake.

- If it's an air volume issue, I thought that the "plumbing" on the intake side of the turbos was larger then the manifold side, so that's not the bottle-neck in the system.

So the only thing left is the air flow, which can probably be addressed with a pair of scoops and a better filter element, fitted to the standard set-up.

I'm sure there's a lot more to it than I understand, but I just don't understand why folks are spending money on DCI's and all kinds of other intakes.

Please feel free to correct my misunderstandings - that's what I'm hoping for.

Cheers.

One thing i did with my Subaru was the intake. However, that's also because there was about 2.5m of intake hosing from the front right guard airbox, into another airbox, then into the throttle.

After the intake installation (which took about 15 mins), there was around 2 feet of aluminium piping.

The new CAI resulted in:

• Quicker throttle response
• Faster rev range
• The Air Intake Detector in the throttle was more accurate as the distance travelled by the air was a lot less (lag).

That's what I saw in the Subaru and it did wonders.

Personally, if you are wanting to change your CAI, I would suggest to go with lighter pulleys first.

[Alext]

Intakes on turbocharged cars are typically less restrictive than OEM and can result in less work done by the turbochargers as air is sucked in and so boost can build earlier.

[TimMc]

I agree with all you've written bfi. I can't understand why you'd want to put twin cone filters under the bonnet instead of drawing in cold air as per the standard set up. The 135 (and other model 1ers?) intake come's from the high pressure area in front of the car too.

[andrew@southernBM]

I run an aftermarket intake and see no horsepower gain on the dyno, i have tried other intakes and also seen no gains, on the road though they do feel different and have spoken to others to have them and they all feel better on the road. I'd say it is an addition to all the other mods, my next tests will include factory air box with panel filters. As for the turbo temps, don't forget the intercoolers job here before they get to the engine.

[bfi2906]

Thanks folks. I feel better now, as i don't feel like the only person not "getting" something that was proven long ago.

Andrew, Point taken on the role of intercoolers and the turbo temp. Clearly that will bring down the temp of the air going into the combustion chamber. Which is a GOOOD thing.

When you say you can notice a difference in road use of your car with an intake. I'm interested to hear what kind of difference you're noticing.

[Totti]

Anyone have the BMW perf. intake? I want it just for the "noise"