3-Series (E21, E30)Chat relating to the BMW 3-Series from 1975-1983 and 1984-1991 line. Specific models: BMW 315, BMW 316, BMW 318, BMW 318i, BMW 320/4, BMW 320i, BMW 320/6, BMW 323i, BMW 320i. E30 Family models include: BMW 325e, BMW 325i, BMW 325is, BMW 325ix.
There seems to be some debate whether or not a cone filter really helps or it just looks cool or something inbetween that; on this forum at least. Regardless, I have a cone filter and noticed the power loss when the engine heated up the moment i put it in. I know i have to make a heat shield, and i knew that before...
but i was wondering if i can put the cone filter in the area infront of the left wheel..?
I'm pretty sure i can run some tubing down there and just make adjustments to the ambient temp sensor, and i know the cone filter fits in there.
Basically I want a true cold air intake and just wondering if anyone has attempted this.
__________________ "Bmw is better than Volvo, Robert"
Retired ride: 1990 325i - Manual - Chipped - Recaro Racing Seats - Eibach Lowering Springs - Original German Liscense plate (for style) - Black HID Halo Angel Eyes - Blacked out Turn signals - alpina rims. :-)
just cone filters without proper heat shielding have usually lost 5whp in a hot engine bay in the e30 dynos ive seen on dyno days.
with proper duct work and heat shielding, you might gain 1-4whp.
everything in the e30 works pretty much at its max stock..that is to say gains are minimal unless you do a lil of everything.. to get real gains gotta modify your intake runners, bore your throttle body, port your heads, do headers, etc..
Don't forget that 87 is the minimum requirement, or in other words you can "get by" with it. I have found that I got noticeably better mileage, a tad better acceleration, and all around ran better when useing midgrade. Fill up on it and drive it for a week to see for yourself. I'd say midgrade is about ideal because I couldn't detect any noticeable increase with premium.
I think that starmavin is correct on the CAI, you need to isolate the filter from the engine bay heat and many systems just lay the filter in the bay. Also, metal tubing unlike plastic tends to draw heat so to me that is a draw back. I have a daily driver (1998 Neon, DOHC and MTX) and on this car, I built my own CAI system. I used 2 1/2" ID plastic tibing and brought the tubing from the throttle body to just behind the front grill or fascial so I am always drawing cooler air into TB, and I use a K&N cone. HP, I would guess a increse of 3-5 (no more). Most of our Bimmers have a enclosed filter box and tubing to the front grill and to me that is a CAI, oh, plastic tubing and filter box as well. Fuel AKI rating is another issue and if your car has a knock sensor you may not benefit from a incresed AKI (my 1988 750 has no knock sensor is rated for 87 AKI and runs just fine on that, I have tried mid-grade, but so no difference). Just my nickel.
I built my own heat shield this weekend. (Garage hack.)
I agree plastic is a better thermal insulator than sheet metal.
However sheet metal with good insulation on it should be better than cheap thin plastic.
But basically for me it was much easier to fabricate a heat shield out of sheet metal than plastic.
I bought enough material to make two one prototype and one final version.
$45 at home depot.
Basically some 26 gauge sheetmetal and pipe insulation with self adhesive.
Built 1st rev prototype this weekend and I'm running /testing it now.
It looks preety good for a first attempt. Looks like the one from Signature Motoring, only cheaper, and I can use the nice bracket from bavauto
I'm still trying to find some good self adhesive sheet insulation that will hold up. Anybody know of some? I'll keep looking, theres an industrial supply store somewhere around here. hmm ,we have a machinist here maybe I'll ask.
But for now the "prototye" shield does seem to eliminate 99% of the air from the engine bay from getting into the intake.
Based on the fact that almost no light can pass from inside the box.
Just not sure about the seal to the hood. Seems to work, hard to see.
I could bring some thermistors and a PCMCIA-DAQ card home and hook up my laptop and get some realtime data with and without the heatshield.
But I'm too lazy for that. LOL
I'll keep you posted.
'87 325is Delphin Metalic
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