I posted a little while back mentioning how I didn't think the apexi flowed as much air as the HKS mushroom filters. When I put the apexi on a few months back the car rarely boosted above 12psi. For the brunters thrash yesterday I fitted the HKS back on as the weather looked good so no rain problems. Straight away I boosted back up to 13.8 my normal amount.

Are there any other reasons for this that anyone can think of or is it purely due to the filters ability to flow air, and the intake diameters, or is it also the limits of the air that the stock size turbos can flow?

It would be nice to see what power was produced with bigger tubs as the engine is built for that, ported and forged internals and all.

Dave

 

 

edit - maybe this should be moved to the private tuning section?

Flow is probably easier through the HKS but it has about the worst filtration of all of them too.

It won't affect what boost you reach though, there must be some other reason.

Thats bizarre! Its a very definate change. I get full boost with the HKS and not quite as much with the apexi. Its only a little less and although you can't feel it, its noticable on the boost gauge on the greddy. I'll probably put the apexi back on again now as I don't want to be caught in the rain with the HKS (I ran it for many months in bad rain through the winter but eventually the MAF went). Think I might put a twin apexi on there and see how that does. Dave

In the tests that are floating about the internet somewhere the Apexi and HKS both flowed the same rates (and both higher than the others) but the Apexi was the best at filteration and the HKS the worst of the group.

 

Not sure why you could be noticing a difference, to be honest an air filter, no matter which make is'nt going to make much difference to the zed anyway.

Funny isn't it? I was curious if there might be any other reasons that people knew of. I quite like being able to experiment though, especially when I can see very obvious changes. I'll put the apexi back on at some point and see what the readings come out at. Dave

Get Smithy's twin cone Apexi filter! :D

Flow is probably easier through the HKS but it has about the worst filtration of all of them too.

It won't affect what boost you reach though, there must be some other reason.

 

Just remembered something else Chris: When the MAF burnt out with the HKS filter I had a blitz sus for about a month and this was as good as the HKS , full boost,etc. I then got the apexi because I was worried that the blitz wouldn't be good in the rain. I'd say thats pretty conclusive? The HKS and the Blitz Sus both gave full boost whereas the apexi doesn't. When I remove the apexi and stick on the HKS again I get full boost again.

Dave