Relocating air inlet?

[Eddles]

From the image here, you can see the inlet is located as far front as possible, to ensure that the air going in the engine is as cold as possible:



Under and behind the inlet, there are no less than 3 radiators (air con, main rad and intercooler) as you can see in this image, is it worth relocating the inlet back inside the engine bay, maybe behind the radiator so the engine would get warmer air which would mean better MPG? Or do you have a better idea of what I can do with the inlet? Or is it a bad idea to play around with something like that?

Thanks very much for your time in advance!

[bikin' Ed]

I would try removing all ducting from the intake up to the air cleaner box. This will give it access to warm air. If mileage decreases, put everything back on. If it increases, then you can experiment with exactly where in the engine bay to locate an intake.

[shovel]

so let me get this straight.

Your car has a turbocharger right?

So you want to heat up the air so it can enter the turbo where it will heat up more, then it will get cooled off by the intercooler.

I recommend a tasty beverage.

[tjts1]

Does heating up the intake do anything for diesel engines?

[MechEngVT]

Why not just put a piece of cardboard on the intercooler? If your mpg or performance goes to crap just take it out.

[Deezler]

I would relocate the air inlet, but only so you can achieve the full upper grill block. Move the inlet down to be co-located with the small, necessary opening for the radiator and intercooler air flow.

Don't waste your time with hot intake air for a turbocharged diesel.

[Eddles]

Originally Posted by shovel

Your car has a turbocharger right?

So you want to heat up the air so it can enter the turbo where it will heat up more, then it will get cooled off by the intercooler.

I recommend a tasty beverage.

My thinking was that if you heat up the intake slightly, the net gain would increase slightly - let me explain. I have no idea of how much temperature gain/loss happens when the air is compressed and cooled, so I'm making wild guesses - purely for example purposes. Let's say the air going in is 20 degrees C, gets heated up by the turbo by 50 degrees to 70 degrees C, then cooled by the intercooler by 30 degrees C, and the net result is 40 degrees C going in the engine. So, if I re-route air intake and achieve a 5 degree C increase in the intake, so 25 + 50 - 30 = 45 degrees C. I don't have a degree in thermodynamics, so I could be completely wrong.

However, this line of thinking is moot, as quite a few people have pointed out that a turbodiesel would benefit more from a cooler intake, rather than a warmer intake anyway, so I'm dropping the idea.

But, I will accept that tasty beverage from you

Originally Posted by Deezler

I would relocate the air inlet, but only so you can achieve the full upper grill block. Move the inlet down to be co-located with the small, necessary opening for the radiator and intercooler air flow.

OK will do that. What sort of material is good to use to extend the intake pipe - I'm a little worried about trying to attach the hose over the flared end. Should I shape the start of the tube as a small funnel to "collect" as much air as possible, or should the start just be straight? Sorry for not being very clear!

Thanks to everyone else for your advice, much appreciated!

[Big Dave]

I don't think it matters either way. Any differences will be too small to measure.

Forget this noise. Concentrate on driving, weight, aerodynamics, and gearing.

[Eddles]

True. However, there isn't much I can do about weight apart from remove seats, rear wiper motor and air con. My car is very basic to start with, I don't even have ABS, and this is a 2001 car.. Driving, I already look at the 108 tips weekly for ideas. Gearing - what exactly you mean there? The gearbox have already been modified by the factory to make the engine spin at 2100rpm at 70mph. Areodynamics, again my car has a low Cd from factory of 0.28. Not a lot I can do apart from wing mirror delete. I thought grill block would improve areodynamics anyway? The main prob here is that my engine takes 15 mins to warm up so a block would mean the engine would warm up faster.

[vtec-e]

FWIW i removed my rear seats recently for a whole tank and it made no difference. That said, i was P&Ging it and probably not too well either. Anyway, if it was going to make a difference it would have shown up. It accelerated quicker but also decelerated quicker too, due to the weight reduction i suppose.
If it was me Eddles, i wouldn't bother with too much weight reduction. Too much hassle for too little (or no) gain.
Relocating the air inlet might make a difference worth talking about. I have yet to relocate mine but i have stuck on reflective foil on the intercooler duct and the entire intake pipe, along with a cold air intake baffle that gets air from the gap above the headlight. Not perfect but no major savings either. A direct feed to the intake may give me something so i have to look into that when i get the time.....

ollie