Using modified stock airbox on single

Hey All,

Just wondering if anyone here with a single turbo setup is using a modified stock airbox?

This is my current filter :-

http://knfilters.com/search/product.aspx?Prod=RE-0880

I remember Dusty talking about this awhile back. But don't think it panned out.

I know afew guys here - have boxed their filters up. And cut louves in the bonnet to feed cold air into the box.

What would be interesting would be to see how much the difference in temps would be. I think everyone is in agreement that it's worth doing.

Just be nice to see some data.

Well i could log the inlet temps on idle after 15min with the current setup and then with the airbox, i am guessing the temps should drop right down.

I'm hoping to have a stock style box made up when I finally get around to fitting the twins, something that will take the standard size filters, very much a pipe dream at present though.

I don't think it makes a great deal of difference if the intercooler is working well. This will drop the temps dramatically before the charge goes into the cylinders. Isn't this all that matters??

I don't think it makes a great deal of difference if the intercooler is working well. This will drop the temps dramatically before the charge goes into the cylinders. Isn't this all that matters??

But what about the air being sucked into the turbo from the filter ?

Colder air .. is bound to be better than hot - should it ?

That was a question btw.

It would be, if there wasn't an intercooler fitted.

Colder air is better than hot, that's true... but if the intercooler is dropping the temperatures by 80 to 90 degrees, what's a couple of degrees in the intake???

If you want the maximum cooling then its worth boxing the air filter up, but if you've got a FMIC or CW SMIC etc that will drop the temps from the high temps of the compressor outlet will it gain much???

I guess the best test is back to back testing with measurement of the temps at the air filter & at the inlet manifold with it unboxed & then boxed. If it shows more than a couple of degrees difference at the manifold I'd be surprised.

Just done a quick calculation. A 15 degree rise at the air filter gives a 4 degree rise at the manifold with an intercooler at 70% efficiency. I expect a large FMIC will perform better than this.

If I get time I will look into this weekend and let people know my findings

When moving i am sure the results will be minimal due to the airflow through the engine bay and over the SMIC but still worth giving a go I think.

Wez, when you run these tests are you planning on boxing your filter up & heat shielding it ? With the temp sensor in the box.

What'd be good is to see data at:

Idle

Cruise

WOT

The only sensor I have is the stock one mounted on the inlet manifold which is measuring intake temp.

I have been looking at ways to modify the stock airbox to take a 4" inlet from my turbo, I have a few ideas but will not know for sure until i try at the weekend.

Just done a quick calculation. A 15 degree rise at the air filter gives a 4 degree rise at the manifold with an intercooler at 70% efficiency. ...

Ah, but such calculations do not reflect real-life situations though.

You see when the i/c is operating at 70% efficiency you will be probably boosting quite hard (off/low-boost i/c efficiency is miniscule)

When boosting hard the vehicle is likely to be also moving quite fast, so the underbonnet air moves fast as well.

The faster it moves, the more the 'dilution' effect of the warmed up air reaching the open filter.

So getting a clean 15C drop in intake temps is not that easy when out on the roads.

It is definately possible - especially if you position the intake well outside the bay, say the empty space left by the old SMIC

My plan is to cut the back off the stock box and then position a nice big 4" inlet and then fiber glass it.

I plan on using 4" plastic piping and silicon joiners, once completed I will wrap the whole lot in some thermo shield from the turbo outlet to the back of the box.

There is no reason to have any metal piping in this area as all it does is conduct heat.

Taking in colder air is waaaaay better than taking in hotter air. The turbo will bring in more oxygen per second as it's denser, and the FMIC has a much lower output temperature to bring down in the limited time that air is in it.

-Ian

My thoughts exactly as it would reduce the amount of work the intercooler actually has to do.

Surely this is the way it should be rather than ingesting all that hot under bonnet air and then trying to cool it.

Quick update, started work on this tonight.

I have prepared the box ready for fiber glass work tomorrow and sunday and also checked alignment upto the turbo.

I nice idea which I have only seen a few times is to mount the intake in the front wing with some clever ducting away from the nasty engine bay temps as johnA mentioned above......food for thought;) I think Alex did something similar with his setup

Bit difficult for me as I have a CW SMIC and piping going that way.

Where is the feed for the cold air coming into the airbox ?

The two stock air feeds, one from under the light and the other is from the top and above the rad.

Quick update as I did not get much done over the weekend, too busy out in the car as the weather was nice.

Started work on the reconstruction of the box using fiber glass, these pics only show one layer, i will keep aplying layers until I feel its strong enough.

Once all layers and basic fitment is sorted i will sand it down and then paint black to look stock, the final item will also be heat wrapped.

Not done any fiber glass work before