Driving without air intake

sdanseo

New thread for this as it's a specific issue and question. E90 320i 2005.

Long story short, had the car in for a check related to what I think is a gearbox rattle (bought it last week so under warranty for that, let's not go there) earlier. I pick it up and he tells me it could be anything from exhaust to a solenoid, but that he'll have a proper look Tuesday, drop it back then. I hop in, and after a couple of km I notice that accelerating is a very noisy affair, accompanied by some vibration in the pedal. Loud noise, as if the thing had a knacker starlet exhaust.

I chalk it down to perhaps his investigation interfering with the exhaust, and make a note to say it to him on Tuesday, without opening the bonnet.Then this evening, I hear a clunk in the boot, but know I've nothing stored there. Open her up and bingo, the front air intake. Sure enough he'd removed it and forgotten to refit it.

I probably did about 80km and drove in my normal style (I would accelerate decently enough, I kept doing this as much to see if performance was affected by the noise and because the mech said he was happy for it to be driven normally) and fast enough on the motorway.

The air filter doesn't seem to have been disturbed - just the intake.

The question is, have I done damage? If the engine didn't get enough air, have I caused issues by running far too rich and has this potential to knacker the engine? Is there any filtration in the intake alone that could mean I've sucked in dirt, etc?

CianRyan

As long as the filter was still there, it's grand.
Your car would have been getting plenty of air, albeit hot, thin air which could theoretically hinder performance.

Best practice is to put it back on and carry on.
If lads can run ITB's with exposed trumpets, doing a few KM's without a bit of pipping is no concern!

Btw, I'm no mechanic so don't come back to me if all does go wrong!

sdanseo

CianRyan wrote: »

As long as the filter was still there, it's grand.
Your car would have been getting plenty of air, albeit hot, thin air which could theoretically hinder performance.

My worry is, would it?

The forward motion of the car drives air into the front intake and from there into the airbox. With that gone, the only air was getting was the air it was sucking in by itself with no assistance from the ram-effect of travelling forwards. It did feel like I had a bit less power than usual which if anything probably made me test the car a little harder than I should have.

All the garage's fault either way so I'm covered, just anxious!

CianRyan

Unless you had a big sheet of card across the front of your car, there's going to be plenty of air in your engine bay, couple that with the vacuum front the engine itself, it's going to be sucking in plenty of air.

Generally, OEM intakes have no ram effect. They just sit in the bay, facing a wall or so far behind the grill that it would make no difference.
Even running a cold air intake have been proven to do sweet feck all for airflow and that would be providing the ram effect you refer to.

Again, people use ITB's for power, that's essentially just an open throttle body sucking air from behind the engine, often facing the bulkhead. No air being forced in there, it's all about the vacuum.