Another thread about CF Plenum and Alpha N

[Razziel24]

Dear gentlemen, I was about to install my CF plenum, but I decided not to.
After analizing both intakes, I saw that the trumpets on the OEM intake are so well designed, that there is never an straight angle on the air path... on the CF plenum, the "trumpets" (they are basically just tubes) are straight and the individual throttle bodies are angled (around 35 degrees) so they collide and form an straight angle on their union. (thats not good for air velocity)
Im guessing, the CF airbox that the CSL uses (or the one Delage Sports sells for above 2K euros), has a better design inside, mine just doesnt seem to be better than the stock one. :(

Now I have a question.... can the alpha N chips be used with the oem intake ? my plan is to use the original intake and just replace the airbox and stock filter with a conic filter (eliminating the MAF sensor) at least until I can find a better designed CF plenum, for a decent price.

[gobuffs]

Guys do it on the S14 all the time.

[Razziel24]

Anyone tried using the oem trumpets on the CF plenum ? I guess with a little work it could be done....

[GazM3]

there are a few CF plenums that hook up to the original trumpets, which is probably the ideal way to go.

On the other Q (alphaN to OEM intake) i cant see why not. Im gunna be doing this in the new year with my s50b32, and perhaps fabricating a filter to bolt direct to the larger squared opening, or if funds allow just get a CF plenum to bolt up to the OEM trumpets

[morerevsm3]

the ebay ones are an exact dimensional copy of Hamann CF airbox, fluid dynamics have more influence than heimholz, just bolt it on, it will be fine

[Razziel24]

Hi Alan, the tubes on my CF Plenum dont seem to match exactly the shape on the ITBs, the ITBs have perfectly round openings and the CF tubes have oval openings, since they are angled, actually some of the holes for boting it up together dont match, did you have to work on them to make them fit ? did you check for any vacuum leaks after the installation ? did you use a gasket on the union between the CF plenum and the ITBs ? I dont know, there are some things that dont look right

[morerevsm3]

I drilled the holes for the studs out slightly larger, and put flat washers under the nuts, I made 3 pairs of gaskets out of 3mm sponge rubber gasket material, the angles won't hurt air velocity. I have ~20,000ks on mine now, a lot of that on race tracks/towing/drifting etc

[morerevsm3]

pic with gaskets
http://i5.photobucket.com/albums/y171/morerevsm3/miscellaneous/Picture539.jpg

[Exacc]

pic with gaskets
http://i5.photobucket.com/albums/y171/morerevsm3/miscellaneous/Picture539.jpg

did you get your box from HK also? I think I have the same one as you...I added resin and fiberglass to flatten it out and also have my own version of the gaskets you made. Mine is still in process but once it is done, it will be tuned...will update on actual difference from stock set up.

[Razziel24]

I got a new set of the six stock trumpets to replace the bad looking tubes on the HK airbox, as soon as ill receive them ill work on the cf airbox to make them fit.

[Exacc]

I got a new set of the six stock trumpets to replace the bad looking tubes on the HK airbox, as soon as ill receive them ill work on the cf airbox to make them fit.


Post some pics when you are done!

[Razziel24]

WOW !!!

Now this looks like a well designed and constructed CF plenum....

http://cgi.ebay.de/Carbonairbox-BMW-M3-E36-Motorsport-GT-Airbox-Carbon_W0QQitemZ180199297722QQihZ008QQcategoryZ401 83QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

http://i3.ebayimg.com/04/i/000/ca/cf/cd24_1.JPG

http://i10.ebayimg.com/05/i/000/ca/cf/cdc8_1.JPG

http://i5.ebayimg.com/05/i/000/ca/cf/cfb2_1.JPG

http://i2.ebayimg.com/05/i/000/ca/cf/d030_1.JPG

http://i19.ebayimg.com/03/i/000/ca/cf/d09a_1.JPG

Check how smooth the shape of the curves are and how round the openings on the trumpets are.... I hope with the experiment ill be doing, ill have something similar... because that Delage plenum its just a little bit too expensive for me.... ill get a 3.64 LSD with 40% lock from diffsonline.com with that money.... LOL

[Exacc]

Yeah that looks to be real nice...anyway, don't have that kind of budget for this car anyway...hope the one I am doing turns out nice..if not, back to stock I go...but I do have a lot of optimism about this :)

[M3 Euro LTW]

WOW !!!

Now this looks like a well designed and constructed CF plenum....

Check how smooth the shape of the curves are and how round the openings on the trumpets are.... I hope with the experiment ill be doing, ill have something similar... because that Delage plenum its just a little bit too expensive for me.... ill get a 3.64 LSD with 40% lock from diffsonline.com with that money.... LOL

I am NOT trying to be the jerk of the forum, the nay-sayer, or implying that I personally can build something better than Delage. The exterior of that box is fine looking. Very nice.

The interior is closest in concept to the 3.2 manifold, implying that its designed for high HP, not torque. While the intake trumpet shape is not hacked off and rough, its far from really smooth, the way the factory trumpets are molded, or the aluminum spun one's are that our Aussie friend will be using. It matters for NA. If someone puts this on a 3.0 engine, they might lose torque and be unhappy unless they've cammed the engine, bumped compression and are trying to maximize HP....

Secondarily, consider the drain tube for the intake plenum. It sits up on an island unless I'm mistaken... its reinforced on the INSIDE of the plenum for strength, so that the outside of the box will be nice and smooth in appearance.... That my friends, (unless I'm mistaken) is ass-backwards, and will not help drain any oil that collects in there, in fact, you'd have to have a TON in there for it to drain out before it ran down the intake and soiled the filter. The drain doesn't sit in a low spot at all, again, unless I'm mistaken.

It doesn't appear to me that the intake is larger than a standard 3.5 inch HFM.... if not, then there may not be much advantage to this over stock other than weight.

Alex.

[morerevsm3]

I am NOT trying to be the jerk of the forum, the nay-sayer, or implying that I personally can build something better than Delage. The exterior of that box is fine looking. Very nice.

The interior is closest in concept to the 3.2 manifold, implying that its designed for high HP, not torque. While the intake trumpet shape is not hacked off and rough, its far from really smooth, the way the factory trumpets are molded, or the aluminum spun one's are that our Aussie friend will be using. It matters for NA. If someone puts this on a 3.0 engine, they might lose torque and be unhappy unless they've cammed the engine, bumped compression and are trying to maximize HP....

Secondarily, consider the drain tube for the intake plenum. It sits up on an island unless I'm mistaken... its reinforced on the INSIDE of the plenum for strength, so that the outside of the box will be nice and smooth in appearance.... That my friends, (unless I'm mistaken) is ass-backwards, and will not help drain any oil that collects in there, in fact, you'd have to have a TON in there for it to drain out before it ran down the intake and soiled the filter. The drain doesn't sit in a low spot at all, again, unless I'm mistaken.

It doesn't appear to me that the intake is larger than a standard 3.5 inch HFM.... if not, then there may not be much advantage to this over stock other than weight.

Alex.
agreed, the HK ones are far superior in trumpet shape to that delage one
http://i5.photobucket.com/albums/y171/morerevsm3/airbox2.jpg