I just made a cover for an open filter element from a spare air cleaner housing. My question is simple, will the higher under-hood temperatures reduce performance by much? I like the sound of the unsilenced open filter, and airflow is probably increased, however will the less dense hot air rob any potential gain?
I will post pictures of my work after I get it painted and installed, meanwhile let me know if you have tried this and what impact it had on performance. I still have a complete stock intake system, this experiment was performed on spare parts so it can be easily reversed.
I made an open element air cleaner for my '84 2.5. I had to make one in order for my SD valve cover to fit. Even though people will tell you that it is bad for performance, I haven't noticed any adverse effects. My intake is not stock though. I have the Holley TBI and Holley intake manifold. See pic.
Thanks, My cover looks very similar, I may cut down the lower section as well, although I will probably just leave it since I will not have the interference problem. Cold air is definitely better but so is greater airflow.
Sorry about bumping my own post but I have an additional question. I once read that the biggest concern with most intake systems is that they are quiet, more engineering work goes into reducing intake noise than increasing airflow (except in the highest performance versions). The 2.5 air cleaner housing is basically borrowed from the X-car sedans, does that mean that this system may be restrictive in order to reduce noise? Does anyone have any more knowledge on this issue?
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09:28 AM
Dennis LaGrua Member
Posts: 15145 From: Hillsborough, NJ U.S.A. Registered: May 2000
While I have never tried putting an open filter element on a Fiero; I have installed free flowing K&N Filter elements. I doubt if you will experience any ill effects with your new air filter and the less restrictive elelment may help.
Just installed the new cover, sure sounds nice. I doubt if there is any real performance advantage but the engine seems to rev a little more freely. Due to once owning a car with weak synchronizers I tend to double clutch on downshifts, the result sounds awesome. The car now has that sports car sound (not to be confused with the raspy "fast and Furious" sound).
I would still like to hear from others who have tried this to determine if there are any adverse effects I have not considered.
Ira
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01:09 PM
FastIndyFiero Member
Posts: 2545 From: Wichita, KS Registered: Aug 2002
I've ran into this also. However, due to the extra height of my intake setup, I think I'll be able to draw air from outside.
Using this highly accurate and scientific drawing I spent 2 minutes on, you may be able to see what I'm talking about.
I believe by enlarging the hole in my decklid then surrounding the bottom of the air cleaner with a sheetmetal plate that rises to meet the bottom of the decklid, I should be able to draw large amounts of nice, cool air.
The dark red is a mustang scoop I'm going to cut in half.
Anyway, enough of my crazy plans. There shouldn't be any significant decrease at all with running an open element.
However, I believe that given the position of the sensor, it won't matter anyway. (I'm not quite sure about that though, I've never seen a stock 4 cyl. intake. Excuse the ignerince )
wuzzy, looks like T-top Fiero has his attached to the dogbone (or thereabouts). I still have my stock lower housing so it is not an issue (not yet at least). I am now working on a more minimalist version with the Thermac removed but will probably leave the rest of the housing as is.
The MAP sensor on a stock air cleaner is merely mounted there. I have mine just setting loose between the intake manifold and the dogbone. I originally intended to make a mount for it out of some sheet aluminum, but I see no need for it now.
Here is my first redesign, I put away my original aluminum coloured intake with red cover so that I can return everything to normal. I plugged the thermac vacuum line at the TBI and I removed the cold intake hose and put it away with the rst of the intake.
I cut the new intake so that it still covered the crankcase breather and then freshened the original black paint. (used a dremel and hacksaw to cut the intake). Here are soem pictures:
Here is an overhead shot, sorry about the Edelbrock sticker, I couldn't resist.
Here is where I cut it:
and finally here is a side view to show where it now ends:
The aftermarket plug wires (Wells) were too short to follow the original routing so I now have them over the top (well clear of exhaust manifold heat).
Thanks to all those who offered help.
Ira
P.S. Added bonus, sparkplugs are now accessable without removing air cleaner. The holly scoop now just pumps air into the engine compartment (probably just as useful as it was when attached to the intake). The sound is great and it does seem to have better throttle response.
The last time I tried this trick was on an early 80s S10 2.8L with a carb and four speed automatic. On that truck the difference was dramatic, with the stock intake it would pull away smartly with hardly a chirp from the tires, but with the cover opened up it would howl the right side tire very easily.
[This message has been edited by Monza76 (edited 05-21-2003).]
Thanks for the input guys, the fact that there have been no negative comments leads me to conclude that none of you have had any problems with this setup. I really like the sound, the only problem is that I discovered a missing bolt in the exhaust system so until it is replaced there is a little harshness to the exhaust note which drowns out the intake sound.
Three things I want in asports car: - fun to drive (=handling) - looks good - sounds right (the deep burble rather than the raspy sound of the import tuner exhausts)