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Thread: Air filter for Twin weber 45s on 2ltr Zetec, Mk2 escort

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    Air filter for Twin weber 45s on 2ltr Zetec, Mk2 escort

    Hi folks.
    Im looking for thoughts on the best air filter for a 2ltr Zetec in my mk2 which has twin weber 45s. filter thats on needs replaced and would appreciate thoughts on the best thing to fit.

    Al.

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    Re: Air filter for Twin weber 45s on 2ltr Zetec, Mk2 escort

    Usual there are 2 options, K&N or look-o-like filters or Foam filters like ITG etc. The foam filter is far the best when it comes to real filtering. K&N only stops larger particles. In Auto-Cross it was impossible to run K&N only. Dirt was passing the filter, a purpose made foam filter with oil over the K&N was the only solution (or running ITG direct but they had to replace every heat).

    But oiled foam filters do have an other problem. When serviced every race, usual no issues at all but if we use them on the road, they need a lot of maintenance. The problem is, when running lower RPM's some air and fuel is reversing and collecting in the air filer (a problem we have less when running flat out all the time). After some time enough fuel is collected in the air filer, one simple backfire during starting and you car is on fire. Only and only if you regular clean and re oil the filter you are save. K&N does not seems to "collect" the fuel so well and they don't have the same problem. I'm not saying the never catch fire but in normal use they don't.

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    Re: Air filter for Twin weber 45s on 2ltr Zetec, Mk2 escort

    Thanks for that, I should maybe have said the car is for road use, with the odd track day maybe.

    I had it dyno'd before the holidays and the chap was telling me about a bmw that he had on the dyno. It made 240 hp with socks on the trumpets and when they did a run with them removed it made 270 which seems an incredible increase and made me really think about the best filter type.

    Where ever I read most of them state they are the best, whether foam, paper etc. Just want to let the engine breath as well as possible, and keep the sh1t out.

    Al.

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    Re: Air filter for Twin weber 45s on 2ltr Zetec, Mk2 escort

    Can't have it both ways! Anything over the inlet will form a restriction and so reduce airflow - the degree of restriction is pretty much inversely proportional to the filtering potential! I've always either used OEM stock or K&N's and never an issue with the latter. I may have to get creative with a Zetec on TB's in the Escort as not a lot of space, bulkhead side!

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    Re: Air filter for Twin weber 45s on 2ltr Zetec, Mk2 escort

    Quote Originally Posted by Ally Mac View Post
    Thanks for that, I should maybe have said the car is for road use, with the odd track day maybe.

    I had it dyno'd before the holidays and the chap was telling me about a bmw that he had on the dyno. It made 240 hp with socks on the trumpets and when they did a run with them removed it made 270 which seems an incredible increase and made me really think about the best filter type.

    Where ever I read most of them state they are the best, whether foam, paper etc. Just want to let the engine breath as well as possible, and keep the sh1t out.

    Al.
    Only if these "socks' where complete against the trumpet it could have made this kind of difference. Normally, if the sock is big enough, far enough from the trumpet the power drop should have been a lot smaller. For low tuned engine or standard cams, the difference is zero. I've tested many times.

    Only problem with the sock, not on mild tuned engines but on engine with high lift cams, the sock "collect" the unwanted back flowing fuel and air and give lots of troubles at "off cam" situations.

    BTW, when he fitted the socks, he also had to re tune the carb. Otherwise he will be running too rich.

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    Re: Air filter for Twin weber 45s on 2ltr Zetec, Mk2 escort

    Quote Originally Posted by katana View Post
    Can't have it both ways! Anything over the inlet will form a restriction and so reduce airflow - the degree of restriction is pretty much inversely proportional to the filtering potential! I've always either used OEM stock or K&N's and never an issue with the latter. I may have to get creative with a Zetec on TB's in the Escort as not a lot of space, bulkhead side!
    Aye I understand the trade of with filtration against air flow. Its a Pipercross PX 600 that's fitted at present, I need to replace the foam anyway but just curious if there is a better option out there. Not a lot of room to play with between the carbs and inner wing right enough.

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    Re: Air filter for Twin weber 45s on 2ltr Zetec, Mk2 escort

    Quote Originally Posted by onyd View Post
    Only if these "socks' where complete against the trumpet it could have made this kind of difference. Normally, if the sock is big enough, far enough from the trumpet the power drop should have been a lot smaller. For low tuned engine or standard cams, the difference is zero. I've tested many times.

    Only problem with the sock, not on mild tuned engines but on engine with high lift cams, the sock "collect" the unwanted back flowing fuel and air and give lots of troubles at "off cam" situations.

    BTW, when he fitted the socks, he also had to re tune the carb. Otherwise he will be running too rich.
    Aye it does seem like a huge difference for something so simple and It would have been interesting to have known the ins and outs of his set up right enough. It just really brought it home to me the importance of getting it right, from start to finish. Ive a new manifold and system going on in a couple of weeks and some other work getting sorted out then will need to find someone to check out carbs etc.

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    Re: Air filter for Twin weber 45s on 2ltr Zetec, Mk2 escort

    You aren't going to reinvent the wheel Ally! Both Sherwood and Wilcox use foam Filters on their BDG Rally engines so they can't be all that bad. As Onyd said they can be prone to absorbing petrol but if you haven't had any problems with your Pipercross then I would replace what you have got and save yourself soom money in the process.

    I have used foam filters, mainly Pipercross for many years and only had one problem with a small carb fire. That was when a NA Cosworth engine dropped a valve and the combustion went through the carbs into the filter. Fortunately the fire was soon extinguised.

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    Re: Air filter for Twin weber 45s on 2ltr Zetec, Mk2 escort

    As explained, as long as you service enough, they will not catch fire without a reason. In one or other way, the oil also protect against fire. Still, for road use, I prefer K&N.

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