hi I've got a few questions regarding the weber conversion I've just done

-does it matter if the sump breather pipe DOESN'T go into the airbox? my neighbour runs a filter on the block of his race car, but can i get away with just aiming the pipe down? why are all the gases fed up into the airbox anyway?

-on the airbox elbow there is a big lardy thing that i think is a switch for cold starts, hence there being an intake point for hot air (off the manifold shield) and a smaller intake for when the engine has warmed. if i take this off completely will it matter?

-can anyone recommend an elbow i can run off the carb (weber 34ich) so that i can put a cone filter on the end instead of the clumsy airbox

sorry for the rubbish explanations!

my breather pipe is no longer is just roughly points towards the airbox, no problems there.

if you remove the hot air feed, it will run like a bag of shit when the weather isnt so special till the engine is hot but otherwise its not too bad.

as for the elbow, you are better off going for a bolt on filter, Danny Lee has some pictures of what i'm gabbling on about in the forsale section, or have a look in the members gallery.

Taking the hot air feed off will matter if you plan to run a cone filter on the end of a length of tubing. In my opinion, you should either keep it standard or change to a bolt-on filter.

A bolt on filter, depending on the size and shape, has an advantage of losing the clumsiness of the original set-up. Everything can be seen and accessed without having to take it off, which for some is a convenience good enough.

If you run the standard setup you will not strictly suffer from carb icing in the winter. If you run a bolt-on filter like I did then you will run into problems with carb icing unless you have a manual choke, normally only on DMTR and DMTL.

The Webcon DMTR/DMTL conversion kit comes complete with a simple short plastic pipe, and you're instructed to cut the rubber crankcase breather pipe just below where it bends to enter the air filter, insert the adaptor, then re-connect to the air filter - all this in order to accomodate the additional height of the adaptor plate between the carb and the inlet manifold. I've got the idea from somewhere that the air filter vacuum helps to clear the crankcase fumes out and for the sake of getting a bit of copper pipe the same ID as the breather pipe and extending it by a centimetre or so in order to reconnect, it would seem worth doing.

The carb icing issue (and you most certainly WILL get carb icing if you don't have the warm air feed connected) isn't just about winter temperatures - you can get it on an average day after doing 70/80 on the motorway for 15 mins. It's the wind chill factor that does it. Play with a K&N if you must, but don't throw the standard pancake filter away - it isn't that inefficient, the inbuilt temperature sensor/flap DOES actually work and you might find that you need it. Grinding to a halt on the M25 and having to wait 10 mins on the hard shoulder for things to warm up again makes you think twice about the warm air feed!

Just leave a hot water bottle in there for the hamster and all will be well.

Good to see you making some changes, must run a bit better than the pooberg?

thanks everyone for that info. all i wanted to do was loose a bit of the bulk from the engine bay, but it seems like it might cause me some unwanted trouble, so therefore its probably better just to stick with the standard filter as it seems that it has it advantages!

Just leave a hot water bottle in there for the hamster and all will be well.

Good to see you making some changes, must run a bit better than the pooberg?

yeh it actually idles normally now, i actually cant believe that its coming from my car!

also, i went up a hill with no trouble today. the mani and carb have definately done something :)

You may be able to get an upgrade panel filter matey?

Come on msn for sweet love-talk?

all i wanted to do was loose a bit of the bulk from the engine bay

Get VERY drunk, and go in there with a BIG angle grinder!

Edited 30 May, 200818 yr by labougie

I'm having a slightly different issue, as you can see I've got a K+N bolt on filter which leaves that crank case breather to emit it's gases into the bay.

In the short term I've just flipped the pipe the other way with a piece of plastic tube so it is at least in front of the air filter.

I can still smell it while I'm driving so I'll be getting a catch tank soon. When I go back to the standard pancake filter set up for winter I'll just block that hole in the filter housing and keep the catch tank.

Somewhere on here theres a f.a.q thread about breather problems which might help you get your head round it. The breather system was modified on the later mk2's to help prevent it blocking which also I believe gives that pipe more slack.

Haynes describes the breather arrangement as a "Positive Crankcase Ventilation System". From Wiki:

As an engine runs, gases from the cylinders leak past the piston's sealing rings into the crankcase (containing the crankshaft and other parts). This leaked gas is sometimes referred to as "blow by" because the pressure within the cylinders "blows" it "by" the piston rings. If this gas could not escape, pressure would build up and cause the engine oil seals and dipstick to be forced out of position. The hydrocarbon rich gas would then leak into the atmosphere. It is therefore an emissions requirement as well as a functional requirement that the crankcase has a ventilation system. This must maintain the crankcase at slightly less than atmospheric pressure and recycle the blow by gas back into the engine intake.

i dont really understand the full function of a catch tank.

it takes the shitty gases and then does what with them?

how does it work and where do all the pipes go?

forgive the noobness

It doesn't do anything with the shitty gasses, it just allows some of the oil suspended in those gasses to condense, so you can clean it out at your leisure. Wearing your best suit, of course. The gasses just discharge to the atmosphere as though you'd just left the breather pipe disconnected. Not quite sure what the point is!

Edited 31 May, 200818 yr by labougie

ok can't see why to bother either then...

next questions is;

on my pierburb carb i had a sort of overflow/return pipe just next to the fuel feed. i tested it with the pipe off and sure enough, petrol was coming out of it. the weber doesnt have a return, but i cant see why i need it so I've just blocked the pipe up is this ok?

ps i think that the return pipe was only being used because i had a dodge float needle and it was overflowing

NO NO NO you'll have a fucking fire on your hands! There has GOT to be a return of some description, whether from the carb itself, or the swirl pot before it, otherwise the pump will be trying to force petrol past the needle jet which the float is trying to close and something will give!!!! On the DMTR/DMTL there are two brass spigots - one for fuel in and one for return. I'm not familiar with your carb - put a pic up?

From what I understand if you have the right kind of breather filter on the catch tank less of the gases escape. As for how much well I'm not sure but I do take Labougie's point, the gases go up into the stratosphere in the end.

Check out the Webber thread and look at Hypojam's engine bay plus Danny Lee's. Also check this thread:

http://www.clubgti.com/forum/showthread.ph...ghlight=oddball

There seem to be slight differences with the way they are linked up fuel pipe wise, don't know if that helps..

Mine has a return and doesn't seem to need a swirl pot but might be worth adding.

Is this the late night webber hour? lol.

Edited 31 May, 200818 yr by MacColl

Webers in the night

Exchanging inlets

Wondering in the night

Where were the main jets

Getting all obsessed

About emulsion tuuuuuuuuuubes

Gawdelpus!

i found my breather was dumping crappy hard bits of carbon in the unfiltered side of the aircleaner

so i got a 90 deg bend and some plain hose, then routed it out the bottom of the car , no more mess and it doesnt stink etc

i dont think the skanky air into the carb helped matters either

ok here are pics of the old/new carbs

this is the old pierburg with the return pipe

and here is the new weber but i cant see where the return could go

You need a swirl pot off a golf. On the bulkhead in this pic.

It has an inlet from the pump, outlet to the carb and outlet to the tank. Pretty straightforward.

Otherwise your carb will overfill causing all sorts of problems

ok cool thanks gaz.

will any old one do?

Whatever you can find as long as it works properly (sends fuel to the carb until there is any kind of resistance then sends fuel back to the tank) But getter to get a metal one as they are slightly more fire proof!