UK-POLOS.NET - THE VW Polo Forum

BeezerDiesel wrote:Agreed with the grumpy one ^^^^

Poor Andy

Nice one Kenny i've got mine on order

just need a Forge DV and an apr and i'll be happy(for the time being lol)

Anyone actually received one yet? Am really tempted myself

Ash

Yeah a got two ordered and got them the other day. U order one Dink ok?

BeezerDiesel wrote:Thing to remember here Kenny is the turbo sucks through the airbox not blows, so the more air it can get in the better.
SEAT wouldn't go to the trouble of designing a seperate intake for the PD160 if there wasn't a very good reason for it. It's not fitted to the Cupra 1.8t Ibiza so obviously the PD160 TDI needs a LOT of air. I guess that's because of the extra fuelling over the 130 to release the extra power needing extra intake air (bearing in mind a Diesel has no throttle butterfly) to keep the exhaust smoke free

Stick your hand over the intake of a PD TDI engine whilst it's idling and it will try and pull your arm in Do the same with a petrol turbo intake and all you feel is a small amount of suction on the palm of your hand because the throttle plate is closed.

Massive compression + no throttle + turbo is why diesels have special air intake requirements. A lot of modern diesels also pump air and fuel into the particulate filter (peugeots in particular) to get it hot enough to do it's job. Diesel exhaust gas temperature is very low compared to petrol and the filters need 600 deg C to work IIRC, so that's another source of air needed.

Petrol turbo airboxes aren't as important. The turbo will simply suck in what the engine needs regardless. Any space with a filter in it will work, although the best results I've seen from fiddling with the intake on any VW engine, inc TDI, is a BMC CDA.

The BMC alone is worth 7hp on a VR6 engine, without a cold air feed, and 7hp with a cold air feed

Manufacturers do things because they HAVE TO, not as some special treat to their customers. And that's one danger with modding. You look at other models in the range and see they have a bigger pipe, or bigger injectors etc and think they'll make a big difference on your own car. Wrong!

The only mods I invest in these days are ones that make a night day difference, like - Coilovers v stock, bigger turbo v stock turbo. A 160 intake pipe on a stock GTI would make negligable differences. As part of a package with other mods, it might help liberate a couple of hp.

BeezerDiesel wrote:Tricks I learnt years ago when messing about with old VW GTIs (which had no turbos obviously) was that a long thin intake gave better low end torque and a short fat one gave better top end. VW were also aware of this and gave the later V6 engines a variable intake that switched between the two.

Indeed, you're changing the pulse tuning of the intake and consequently the cylinder filling efficiency. Long inlet tracts also quieten induction roar and in a lot of modern VW airboxes, you'll also find a helmholtz resonator.

The variable intake for the VR6 effectively turned the engine into a twin 3 cylinder below 4000rpm, and 1 big 6 pot above 4000rpm. It never made a huge difference tbh and VW canned the idea. Schrick bought the intellectual rights to the design from pierburg and designed their own version, which you can still buy now!

BeezerDiesel wrote: Lots of swirl is desirable in the intake but with modern engines the MAF and it's housing is the weak point. I would think a Cupra R/TT 225 MAF housing would be a good upgrade if you start making lots of holes in your airbox. Just my 2p worth and I'll bend over and get ready for the flaming.....

A 3" VR6 MAF housing would work too and I have a 4" MAF housing too, which has 40% more flow than the 3"

MAFs are a pain in the backside. They're fine and meter well on a stock engine, but get any turbulence near them from a bigger turbo, and they over fuel like mad. Speed density fuel metering (MAP) is a lot more stable and efficient for forced induction engines, but it's more difficult to map properly. MAFs are cheaper and easier to implement.

just thought i'd post to say i got mine today from simon

And this is for both parts, ie trumpet and pipe?

Will email him now

Ash

Yes