Intake at the front, or the back

[Lowe]

Well, the BMC CDA's arrived. Now, normally you set these things up so that the intake is on the front of the car, typically replacing the foglight. This is all well and good, but some induction kits sit with the intake sticking out the top of the engine bay taking air from the scuttle area at the bottom of the windscreen. Supposedly the air there has less pressure, which means the engine can breath easily. Ram air intakes (depending on where you read) suggest that they help to pressurise the air into the system though somewhere else I read that the performance increase could be as little as 1.2% at 100mph.

So.. how shall I hook this up? Scuttle or foglights peeps?

[Zak33]

depends if you wanna hack your scuttle apart it'll look silly with a hole there, si it'll need to be grilled....which may defeat the idea

[DR]

Woosh Straight over my head...

[malfunction]

Woosh Straight over my head...

Yup... me too... Didn't see which forum this was in (viewed it from the new posts link) and thought he was talking about PCs!

Edit: I don't even know what a scuttle is! (Wasn't it one of those robots in Red Dwarf? )

[Lowe]

No need to hack the whole scuttle up, I can (in fact already have, ages ago) removed part of the engine/bonnet seal and stick a scoop (just like the Maxi pic below) there



Surely low pressure air would mean the engine would struggle to breath at high RPM?

[Shad]

If I were doing it I'd do it near the windshield, mainly because you're a bit less likely to suck up water from splashes from puddles. Even so I'd be worried when washing the car or if it was raining hard.

[Rave]

Edit: I don't even know what a scuttle is! (Wasn't it one of those robots in Red Dwarf? )

That was a Scutter. Anyway Lowe, I can't answer your question with any authority, but I do know that you don't want to be taking your intake air from an area of low pressure, that would reduce the amount of air flowing into the engine. It occurs to me that the intake on the rally car might be there to stop water getting sucked up as it goes through puddles/ standing water at high speed, not because of any breathing efficiency benefits.

Rich :¬)

[Matt]

but they wouldnt have put it there if it was going to impact on performance that much would they?

[IainB]

Lowe,
Sorry mate, cant find the mag it was in and an online search as to the reasons why isnt showing up much either.....
But if a Calibra running a 706 CI and running nearly 7 secs on the 1/4 has one.... it must work surely?

[Lowe]

It occurs to me that the intake on the rally car might be there to stop water getting sucked up as it goes through puddles/ standing water at high speed, not because of any breathing efficiency benefits.

I think that might be the real reason. CTRs suffer from heat soak at the front of the bay (manifold sits there) and rally cars go through all sorts of crap. I think I'll take it to the front of the car since the run will be the shortest and have the least amount of kinks in it.

Cheers guys.

[Zak33]

I think it should suck in from the cabin. With the windows closed.

That way you'll drive slower cos everytime you boot it hard, you'll suffocate and your eyes will pop out of your head

[Tumble]

I think it should suck in from the cabin. With the windows closed.

That way you'll drive slower cos everytime you boot it hard, you'll suffocate and your eyes will pop out of your head

omg... funniest quote ever ^^^

[Butuz]

Well as a N/A engine sucks air in at atmospheric pressure without any assistance, then forcing more air in via high pressure intake from the front should theoretically give more power as long as your fuelling can increase match the increased volume of air, then you should get more power at high speeds?

After all, thats all a turbo and supercharger does, increase the air pressure and therefore volume of air going in. Fuel to match, and bingo, more power.

Thats as i understand engines anyway, which isnt much

Butuz