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Induction idea

Everybody is aware of how hot 16v engine bays are, and the associated hassle of getting cold dense air into your intake.

I have thought about taking my piperX induction filter and mounting behind some mesh in the front bumper, basically outside the engine bay and away from the majority of the heat build up (could look cool in a cutout in the bumpoer if done right).

Obviously a big bore pipe would run up onto the throttle body from the filter and would be of a large bore and fairly sturdy to prevent from collapsing at big throttle openings, it would also be insulated (exhaust wrap or something).

I know without dynoing this, or even seeing how it flows on a flow bench it is difficult to say how well it would work. Can anybody see any major flaws in this idea that I aint, and if so, please let us know.

Alex M
  Williams 2, STi N12

The approach I took on my Willy was to use some exhaust wrap and cover the manifold completly. It now takes quite a long time for it to get super hot under there, plus it aids getting rid of the gases by keeping them hot and free flowing.

The only issue I can see is all the sh*t and muck it is gonna pick up from road, plus the risk of damage to the element from stones etc.. Personally I would keep it where it is and just run some additional feeds to it so when you are moving the only air it is getting is from outside your bay.

It is a big piperX filter and it could be protected from dirt and grime by using a little thought when mounting and protecting it, probably require extensive modifications to the bumper but could look cool.

If fitted inside a scoop as well, and the large diameter hose was air tight and insulated all the way back to throttle body it would only ever get nice cold air.

My main concern would be whether the piperX on the end of a long pipe would be restrictive to engine breathing or not, if it wasnt and it could be mounted so it looked good and was protected from the majority of road crap then it could be quite good

What do you all think

Alex M
  Williams 2, STi N12

You seem pretty keen on this so go for it. As i said earlier I wouldnt but then again I am not you. As long as it is well protected from damage then I cant see it been a problem. I have never fitted a element on the end of a long pipe before, for the dusty rallies I always have a long duct running up to the top of the windscreen aka WRC, but the element stays in the same position. Having said that there are a few cars that run with the filters popping out of the bodywork i.e. the racing TVR Tuscans have them out of their bonnet.

Just make sure the duct is free flowing and has no sharp bends. Another issue which you may just have to guess is the bore size as this is normally tuned to the engine as a package. The duct will contain air as it gets sucked through by the engine however using a bigger bore doesnt automatically mean you will get more air into the engine as the pressure will be less than using a smaller i/d duct.

Not sure about this but somebody else may want to comment if I knob it up...measure the existing i/d of the duct and its length. From this you can work out the total internal area. Then to keep the pressure the same with the new one try and keep this area number the same. Thus for a given volume of air (assuming it is at a constant temperature) it will have a constant pressure. The only snag is that the temp/pressure of air will no doubt vary throughout the length of the new pipe. The only way to do a proffesional job is to use some very complex CFD analysis but I guess for this DIY project you shouldnt worry and just get on and do it!!!
  BMW 320d Sport

Well you should give it a try. Remote filters can work and youll certainly have a better cold feed. Whether this will outweigh any disadvantage you may get from the length of the inlet tract (on a 16v the filter is normally bolted direct to the throttle body), I dont know. Try it and see? Thats the only way Ive ever found stuff out and Ive been through 3 or 4 different induction systems with another on the way!

Does wrapping an exhaust really help underbonnet temperatures? Would it be worthwhile trying it on a mk2 172?

  Williams 2, STi N12

Well it did on mine. For sure it still gets hot after a good spanking as it isnt just the exhaust that makes the bay hot, but for short drives it is a lot cooler, plus it helps the gases escaping do it more effectively whithout upsetting the pulses that much.