K & N 57I

[BeelZibub]

Is it worth sticking a k&n 57i on a 523i e39???

What gets me is the stock box is running a cold feed but the k&n looks like it will suck all the heat and shite from inside the engine bay - how can this improve performance???

I have just ordered one but am now having second thoughts - any info would be greatly appreciated

Thanks

[Stuka]

heat shield? if you bought one without it, then your going to lose horsepower. Your not driving a honda here, bud.

[BeelZibub]

K&N 57i's don't come with a heat shield - even if it did it couldn't be as efficient as a sealed box pulling in cold air from outside the engine bay!

Think I might mod the original filter box somehow to enclose the k&n

[sp0rky]

Im not sure which specific filter your talking about... But the reason cone shaped - or whatever filters work better is that there is more filter area, meaning the engine can get more air. You are right though, it won't be getting cold air. One thing you can do though, is make a heat shield with some piping going down into the fender or other area similar, so cold air is forced into your heat shielded area.

btw - that 'you dont drive a honda' comment is getting real old, he was asking a question, not suggesting doing something from a honda. Not to mention a Honda air box is extremely similar to a stock BMW one - and it too is ducted to cold air from outside of the engine bay.

[BeelZibub]

Thanks for the reply sporky I have read about a guy using 6" ducting to greate a cold flow to around his cone. I don't think they sell the 57i in the states for some reason.

Well I think I'll just let the order arrive and see what happens when fitted.

By the way - If it was a Honda I wouldn't be asking this question, I'd just drill a load of holes in the bonnet.