The Danger of Cold Air Induction

[Grant]

We've all heard of the benifits of CAI but I discovered a big negative last Thursday night in the torrential rain we had here in parts of Newcastle. Danae was driving home to get the car undercover, only going slowly, when she hit a mini lake in the middle of the road. The CAI was in the usual spot and did a nice job of funneling water straight into the engine. Engine of course stalled and with no way to get out of it, water then leaked in and saturated the carpets.

[oldcorollas]

it actually bent the valves?
how did it bend the valves? hydraulic lock would kill piston first because the valves are closed.... or did the water somehow break timing belt and make it interference?

thermal damage not so likely methinks.... is only 100 or so degrees difference, and not l;ike it was wholly plunged into cold water...

anyway, pics of bent valves or ban

it only takes a little water to stall car, but a lot to cause hydraulic lock.. but i am happy to be educated otherwise

[RWDboy]

To cause piston killing hydraulic lock you need to *pump* a fair bit of water thru the motor, it's not easy !

I'm of the school of thought that you are more likely to bent a rod, or at least cause head gasket failure when pumping a fair bit of water thru the motor. Bending valves would be real hard to do.

[Grant]

Bent valves a theory as all compression is now between 25-50 psi. There is no mechanical noise when the engine is wound over which would suggest the pistons/rods are intact. Timing belt is fine as well; that was the first thing I checked. The cars nose was immersed in water (waist deep). The supercharger inlet/outlet was full of water and one bore was also nearly full. The engine definitely did hydrolock.

Bent valves is also the mechanics guess due to the fact the compression fairly even across all cylinders. At some point I will pull the head off to have a look.

[oldcorollas]

oh... having a PD blower pumping water into it makes it a little different

hmm....TB is before SC right? so if car was being lightly driven, it still should have reduced rate of water inlet to SC... would have been sealing nicely for a few seconds

anyway, pics !! be inbteresting to see just what happened!

[no_tofu_speed]

I'm only Maitland way.... I didnt think the rain was that bad, dayum.... how low was your cai?

[YLD-16L]

Sorry to hear that Grant. But it's exactly why I went the way I did with my CAI (two 3" feeds with one just below the bumper and one at bonnet height). The low one will never "suck" water in because if it did become submerged the upper feed would save it. If both became submerged then it would be fubar anyway as only a snorkel would save it

Hopefully people can learn from your experience and choose wisely how they set up their CAI and where they draw the air from.

[Ben Wilson]

oh... having a PD blower pumping water into it makes it a little different

hmm....TB is before SC right? so if car was being lightly driven, it still should have reduced rate of water inlet to SC... would have been sealing nicely for a few seconds

anyway, pics !! be inbteresting to see just what happened!

At cruise, the supercharger shouldn't have been engaged, or at the least the ABV would have been open. I don't think the supercharger would have made much difference.

[driftymcgee]

I've seen the new Vectras have the same problem stock, low air intake & big puddle = bent valves

[oldcorollas]

I've seen the new Vectras have the same problem stock, low air intake & big puddle = bent valves

weird... so how does it mechanically bend the valve itself?

[takai]

Ignore the insane ramblings of my fellow cubicle dwellers. They serve only to make my life a misery and a mockery.

Well you see oldcorollas, its like a river. The water hits the back of the valve and because the valve is only designed to have air hitting it it will therefore bend... just like rivers, and water, and erosion..... n stuff.

[Adam_Cressi]

After reading this im am now starting to wonder weather CAI is a good idea or not
if i made 2x 90deg. bends in the pipe, would that prevent this from happening?

[fixeruperer]

its cold air induction not try and aim to suck up water or shit do it right dont put it in harms way.

[ra40celica]

seen this happen on a car, some lady drove through a massive puddle, and the engine was full of water, the air box was full as well. as for bending valves, i wouldnt think this would happen from water.

a rod would only have to be bent very slightly to lower compression? while still being able to rotate

[myne]

I'd go by the more likely theory that you bent the conrods.

Hydraulic lock will do that VERY effectively.

http://www.prepsparkplugs.com/hydrofact.htm
http://www.eng-tips.com/viewthread.c...116998&page=10