My Cordoba Coupe Trackday Car Project

[DPJ]

Stu, is there airflow from the grille below the level of the front of your intake box.

If so, how about blanking the front of the box and having a long slot across its base at the very front.? That way, you'd minimise any ram air effect and also any rain ingress...........

 

[F2 Stu]

Yes there is but not much.

You mean like a restrictor plate mounted to the grill itself?

 

[DPJ]

Seal the front of the box completely. Cut out where I have shaded yellow for the air inlet (forward of where the filter is? ). You could also do with popping two or three drain holes directly below the intake trumpets.

 

[F2 Stu]

I considered drain holes and thats no problem, I see where you coming from - it would need alot of altering but do able if needs be

 

[WeeJase]

i doubt drain holes are going to make much effect unless you intend going through a ford at 60mph.pop your bonnet after a drive in the rain,there's not a great deal of water in the engine bay.and whats going into the air box is filtered so i "reckon" its's not going to cause any problems,especially if the car is not a daily driver

 

[RobT]

a 2L engine consumes 2L air per revolution, if running at 4Krpm, thats 8000L/min or 130L/sec ! Thats without any forward motion contributing. 260L/sec at 8K !

Thats going to be trying to get through a fairly small area filter so even if theres only a small amount of water in the air, its going to get in

think long and hard about this design......will be fantastic in the dry but in the wet could cause probs. They use similar 'looking' systems in F1 and tourers etc but there is a lot of internal structure in the boxes and they are not as simple as they look

K+N do a hydrophobic cover material for their filters that is supposed to help with waterlogging, may be useful

 

[m0rk]

Stu, what's the cross sectional area of the inlet to that box? (or just dimensions if you're feeling lazy)

 

[F2 Stu]

Approximatly 24x4"

 

[RobT]

any sign of my file mOrk ?

 

[F2 Stu]

a 2L engine consumes 2L air per revolution, if running at 4Krpm, thats 8000L/min or 130L/sec ! Thats without any forward motion contributing. 260L/sec at 8K !

Thats going to be trying to get through a fairly small area filter so even if theres only a small amount of water in the air, its going to get in

think long and hard about this design......will be fantastic in the dry but in the wet could cause probs. They use similar 'looking' systems in F1 and tourers etc but there is a lot of internal structure in the boxes and they are not as simple as they look

K+N do a hydrophobic cover material for their filters that is supposed to help with waterlogging, may be useful

Ive got a vague recollection of messing around with a dirtbike many many years ago and I once had the job of saturating the foam filter in some sort of sticky blue goo that repels water - same kinda stuff?

 

[max_torque]

a 2L engine consumes 2L air per revolution, if running at 4Krpm, thats 8000L/min or 130L/sec ! Thats without any forward motion contributing. 260L/sec at 8K !

er, no it doesnt, it consumes 1l per rev (assuming it's a 4 stroke and has 100% vol eff!!!!)

ingesting water isnt really an issue, until you ingest enough to hydraulic lock the engine (i.e. more water than the "clearance" volume in any particular cylinder)

I think that as long as you have some drain holes to prevent "pooling" in the back of the airbox (and the resultant possibility of gulping a large volume of water) then all that some rain will do is to reduce the engines performance a bit, either through a "clogged" filter" (which will quickly dry) or via the water displacing oxygen and reducing the effective charge density.

I suspect the 2 biggest things to watch for are:

1) when it rains and the car is stationary water doesnt run off the leading edge of the bonnet and pool in the airbox (easy to check with a hose pipe)

2) dont go crashing "rally styleee" into large puddles etc, so that the wall of water thrown up isnt just sucked into the airbox.

 

[F2 Stu]

The leading edge on the mouth of the box is sloped so any fluid will run back out with no flow of air going into it.

Had wondered how much water it would have to ingest to do any damage (not that I want to find out!) theres water/methanol injetion on forced induction or is that a different ball park?

 

[RobT]

duh...yes, brain fart, only 2 cyls on induction per revolution so half the air consumption figs above, but thats still a lot of air.

Try sucking air through a wet sponge to see how easy it is.

Most of the time its going to be fine but what concerns me is big downpours like we get on our sodden island, and this being fitted to a daily driver thats going to be on motorways behind lorries etc etc. Probably worrying too much about it but better to think these things through, you've had enough problems already

That blue sticky stuff for motorcrosser filters is to stop dirt. What i was thinking of was something like this http://www.knfilters.com/snowmobile.htm

 

[F2 Stu]

One can be never be too overcuatious, prefer the belts and braces approach myself, if I get in the middle of a downpour I'll stop and blank off the grill with tape or an insert as i have dne twice allready - its like owning a cabrio

Its no longer the daily driver I might add, daily commute is 5 minutes eachway and the golf is proving far more practical than I 1st thought it would in comparison!

 

[andyj]

Stu,

If you need a pair of wishbones to fit polybushes to, I've got the ones that m0rk gave me off the van

FOC + p&p if you want 'em

Andy

 

[F2 Stu]

Andy, yes please

 

[m0rk]

they're better than that... they were off the valver & nearly new

 

[rich.h44]

You were talking about the ram air effect early in the theard,my air box feed is right in the middle of the engin bay and i was goin to put a cold air feed from the front bumper on to the air box,would this be classed as ram air?and would it effect the car if i did it?as it all confuses me!

 

[m0rk]

it's fine on your car I imagine.

I did some sums for stu's car regarding positive pressure etc, lots of high rpm & speed required.

I'll redo the graphs soon, as I deleted them

 

[andyj]

well, 1 of them is off the valver, and 1 is off Em's 1.4 Mk2

they're identical though!

Stu, drop me a PM and we can sort them out.

I'm heading down to see Pete tomorrow (Saturday) so I can take them with me if that's any use..... get them a bit closer!