Chris Wilson Posted July 9, 2007 Share Posted July 9, 2007 The MKIV doesn't have a filter, does it? Quote Link to comment Share on other sites More sharing options...
JohnA Posted July 9, 2007 Share Posted July 9, 2007 What's that bulbous thingie just before the sensor then? I haven't opened it up but I would have thought it's a filter. I was reading a book on technical details of EFI sensors and when I came across this I thought 'aha, never thought of that' Quote Link to comment Share on other sites More sharing options...
Chris and Alana Posted July 9, 2007 Share Posted July 9, 2007 Iv been reading this thread and all the previous discussions about after market air filters, I always find them interesting. Iv now gone back to the standard box and have an apexi filter but what about the standard paper filters. . . are they all the same? for example, will a halfords filter element be the same as a Toyota one for example? Iv always wondered and figured it may be the right time and thread to ask. Quote Link to comment Share on other sites More sharing options...
JohnA Posted July 9, 2007 Share Posted July 9, 2007 I would also be interested to know that, I've never come across any such tests for pleated paper elements. I know of *oil* filters and those are definately not the same inside, irrespective of price almost. For those, OEM is the safest bet. Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted July 9, 2007 Share Posted July 9, 2007 What's that bulbous thingie just before the sensor then? I haven't opened it up but I would have thought it's a filter. I was reading a book on technical details of EFI sensors and when I came across this I thought 'aha, never thought of that' It's a pulsation damper, MAP sensors are sometimes very sensitive to fluctuating pressure waves in the intake manifold. If you give it an un-damped feed and look at it's signal on a scope at idle, and then connected to the stock damper, you'll see what I mean. The 2JZ-GTE does give a fluttery signal at idle and under boost, anyone with a basic pneumatic boost gauge with no damper in it, or in the line, will see and sometimes hear the needle pulsating. Quote Link to comment Share on other sites More sharing options...
dandan Posted July 9, 2007 Share Posted July 9, 2007 It's a pulsation damper, MAP sensors are sometimes very sensitive to fluctuating pressure waves in the intake manifold. If you give it an un-damped feed and look at it's signal on a scope at idle, and then connected to the stock damper, you'll see what I mean. The 2JZ-GTE does give a fluttery signal at idle and under boost, anyone with a basic pneumatic boost gauge with no damper in it, or in the line, will see and sometimes hear the needle pulsating. Which is why trying to map an engine running a 290+ degree intake cam can be a total whore on a speed density system. I've developed my own little damper using a plastic fuel filter and a little restriction in the feed to go with it. This is not on the Supra by the way! (Sorry for the slightly off topic post there, but it's kind of relevant) Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted July 9, 2007 Share Posted July 9, 2007 Try mapping something with lairy cams on an AFM.... Quote Link to comment Share on other sites More sharing options...
dandan Posted July 9, 2007 Share Posted July 9, 2007 I have dabbled in that Chris (kind of lairyish cams - 280 inlet/290 exh) but i think the natural damping in the intake system helped preventing any real reversion by the time it might have found its way back to the MAF. Then the plenum intake was binned, intake cam changed again to something wilder (can't recall now) and it went to Alpha N tuning but nevermind (needs must when using throttle bodies and big cams I suppose). Quote Link to comment Share on other sites More sharing options...
Ian C Posted July 9, 2007 Share Posted July 9, 2007 I found out how bad things go if you use a non-dampened takeoff here: http://www.mkivsupra.net/vbb/showthread.php?t=97683 Shame I deleted the picture off my webspace so the "moral of the story" line is now meaningless -Ian Quote Link to comment Share on other sites More sharing options...
jazz1 Posted July 9, 2007 Share Posted July 9, 2007 is the k&n panel filter ok for the stock box? Quote Link to comment Share on other sites More sharing options...
dandan Posted July 9, 2007 Share Posted July 9, 2007 That's what I used for a long long time - no issues with it my friend except I think it may have been a tiny bit louder than the OEM one. Quote Link to comment Share on other sites More sharing options...
JohnA Posted July 10, 2007 Share Posted July 10, 2007 It's a pulsation damper, ... Learn something every day:thumbs: Quote Link to comment Share on other sites More sharing options...
tDR Posted July 10, 2007 Share Posted July 10, 2007 Good to see no accelerated wear type issues with K&N stuff given my recent update: Quote Link to comment Share on other sites More sharing options...
dangerous brain Posted July 10, 2007 Share Posted July 10, 2007 Box looks good there. Isn't the filter on the wrong way round though Seriously why is it that way round and not like all the other manufacturers with the fat part of the cone connected to the induction pipe and the blank end being the small end of the cone? Quote Link to comment Share on other sites More sharing options...
tDR Posted July 10, 2007 Share Posted July 10, 2007 Box looks good there. Isn't the filter on the wrong way round though Seriously why is it that way round and not like all the other manufacturers with the fat part of the cone connected to the induction pipe and the blank end being the small end of the cone? Cos it's one of these new fangled K&N's with no blank end: http://www.mvpmotorsports.com/Merchant/kn_mk4.jpg From this product range: http://www.knfilters.com/universal/X-stream.htm In short, better flow / filtration with this design. Cheers, Brian. Quote Link to comment Share on other sites More sharing options...
JohnA Posted July 10, 2007 Share Posted July 10, 2007 Good to see no accelerated wear type issues with K&N stuff given my recent update: Fantastic. What are your leakdown figures then? Quote Link to comment Share on other sites More sharing options...
tDR Posted July 10, 2007 Share Posted July 10, 2007 Fantastic. What are your leakdown figures then? Stock...... I've just changed to this setup I do have a leakdown tester that rigs up to our compressor but have had no inclination / reason to hook it up to my Supra. If I ever have any running problems, that would naturally be one of the first diagnostic tests I would perform. With that said however, the leakdown figures after 3,000 miles for my brothers homebuilt 3S-GTE engine with Apexi induction kit fitted were negligible at around 1psi. What are your leakdown figures then, oh great OEM part advocate one? Cheers, Brian. Quote Link to comment Share on other sites More sharing options...
Chris Wilson Posted July 10, 2007 Share Posted July 10, 2007 Actually, leak down figures are a percentage figure, not an absolute PSI figure. A good race engine might give less than 3%, a new road car engine less than 10%, and a tired road car engine about 20% or more. Quote Link to comment Share on other sites More sharing options...
JohnA Posted July 11, 2007 Share Posted July 11, 2007 Being of an obsessive nature I'v always kept a leakdown history after a rebuild. Otherwise you haven't got a clue apart from "it's smoking" or "it isn't smoking badly" lol. Using a K&N panel filter (new, freshly oiled etc) had my previous car go from 92% down to 83% in 20K miles. After I rebuild it (new rings and head polish mainly) I only used paper filters with a modified ramair intake. Leakdown went up to 95% and it *stayed* there (give or take a couple of percentage points that could be neither here nor there) for the next 15K miles despite running ridculous amounts of boost occassionally.(finally it blew up once the water/meth injection didn't bother to kick in) Leakdown practically didn't change at all with the paper element, but it was going downhill with the K&N. (and it wasn't even a cone or a foam!) Note that this is not an isolated experience, in fact it's rather typical. PS Don't confuse leakdown with compression tests! Quote Link to comment Share on other sites More sharing options...
tDR Posted July 11, 2007 Share Posted July 11, 2007 Actually, leak down figures are a percentage figure, not an absolute PSI figure. A good race engine might give less than 3%, a new road car engine less than 10%, and a tired road car engine about 20% or more. Yep, the tester we have is a 2 gauge affair with colour bands for severity of leakdown on the right hand gauge along with pressure on both. We already knew the compression test figure was 180psi on all cylinders so easy to arrive at a leakdown figure given the needle was right at the top of the right most band and barely moved. JohnA - Interesting figures. How long ago was this? I'd like to think it wasn't typical and that the K&N filtration is actually pretty good. Where do you get your assertion it's 'rather typical' from? Cheers, Brian. p.s. Where's the confusion? Or are you just trying to impress everyone with your huuuuuuge knowledge again that us mere mortals couldn't possibly understand? Quote Link to comment Share on other sites More sharing options...
Clarkey Posted July 11, 2007 Share Posted July 11, 2007 What are your leakdown figures then, oh great OEM part advocate one? ... Don't get him started !! Are you just trying to impress everyone with your huuuuuuge knowledge again that us mere mortals couldn't possibly understand? Next he'll be arguing that ditching the OEM radio isn't a good idea - because an aftermarket one has some effect on the electrical current drawn. Or maybe when he was arguing at some point that high AFRs were acceptable on WOT on his Calibre. .. I can't find the thread in question - but I know Alex & Ian .. "corrected" him. Quote Link to comment Share on other sites More sharing options...
JohnA Posted July 11, 2007 Share Posted July 11, 2007 JohnA - Interesting figures. How long ago was this? I'd like to think it wasn't typical and that the K&N filtration is actually pretty good. The period six to three years ago. I had done similar tests before on motorbikes, but they were not as often or as accurate. Hell, for a few moons back then I even thought Slick50 covers the bores:rolleyes:. The teardown after next failure proved this to be hot air ofcourse... Where do you get your assertion it's 'rather typical' from? Assertion? you wish... I've even got somewhere a link from the Porsche944 forum from a guy warning everyone to avoid such filters after discovering the very same issues. It could be on my website somewhere. p.s. Where's the confusion? Or are you just trying to impress everyone with your huuuuuuge knowledge again that us mere mortals couldn't possibly understand? I hadn't noticed that you had the twin-gauge tester, so my postscript was off the mark. But if you're jelous thinking that I've got huuuuuuuge knowledge then rest assured that I don't. I've made more stupid mistakes than you can imagine. Relax:d Quote Link to comment Share on other sites More sharing options...
JohnA Posted July 11, 2007 Share Posted July 11, 2007 ...Or maybe when he was arguing at some point that high AFRs were acceptable on WOT on his Calibre. .. . My supra runs even higher AFRs:cool: Quote Link to comment Share on other sites More sharing options...
Clarkey Posted July 11, 2007 Share Posted July 11, 2007 My supra runs even higher AFRs and will probably blow up soon Init! Groovy! /vbb/images/smilies/bbcode_shock.gif Quote Link to comment Share on other sites More sharing options...
Ian C Posted July 11, 2007 Share Posted July 11, 2007 And this is why JohnA had the dubious honour of being the first person to ever go on my ignore list all that time ago. When I got an email from Shell head office themselves stating the octane rating of Optimax was at least 97 and he still wouldn't have it, well, may as well argue about the existence of God with a suicide bomber. Please stop quoting his posts btw kthx -Ian Quote Link to comment Share on other sites More sharing options...
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