Alternate 308 Aluminum Air Cooling Tube Supplier Located

Discussion in 'Technical Q&A' started by dave80gtsi, Apr 13, 2004.

  1. dave80gtsi

    dave80gtsi Formula 3
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    Nov 3, 2003
    Full Name:
    Dave Meredith
    There's been a few posts here over the years lamenting the apparent difficulty in finding a supplier for the simple 308 flexible aluminum air duct which leads from the right side engine air intake scoop. The purpose of this tube is to direct cool outside air onto the exhaust system (specifically, the catalytic converters). While the exact OE part might still be available from the various well-known parts vendors, I'm always on the lookout for a bargain on what ought to be an inexpensive commodity item. So, I have found this one in the latest J.C. Whitney printed catalog (also available on line).

    The OE aluminum tubing features an I.D. of about 2-1/2", and it slip fits around the OUTSIDE of a matching 2-1/4" nozzle molded into the fiberglass / plastic air diverter. J.C. Whitney offers a similar aluminum tube, used in old air cooled VW's, but which instead has a smaller I.D. of 2". Thus, the Whitney tube is a perfect fit into the INSIDE of the aforementioned nozzle, and that's certainly close enough for this non-critical application. If needed, a simple sheet metal screw can securely hold it into place, with a bead of silicone edge sealant to close any unwanted gaps.

    Specifically, J.C. Whitney item no. 15 ZX 0292 W gives you a pair of these aluminum tubes, each sized 2" I.D. x 18" long (OE part is about 15" long or so), so you will receive one to use and one to give to a buddy. Grand total for the pair is $4.99.

    Although I personally have not ordered this one, I also see in their catalog another similar item, also 2" I.D. but a bit longer in length at 21" for $2.99 each tube. If you wish a little longer length, and have the luxury of an unlimited budget which fortunately allows you the resources to spring for the additional $0.50 per tube (!!!), order their part no. AHG 737173 P instead.

    Of course, standard disclaimers apply - Mine is a U.S. version 80 GTSi, yours might well be different, blah blah blah.

    Me, I am going to do some experimentation this weekend so to see if I can reroute this tube. Since I am no longer using any cat converters, I am going to try instead to redirect the outlet of the tube to blow this outside cool air onto the alternator, as these guys look to get well cooked, being tucked up beneath the front header and out of the way as they are. Since I now have 3 feet of tube length to work with, and since the diameter of the Whitney tube is a tad smaller than the OE tube and thus should be easier to maneuver, I suspect this idea can somehow be made to work.

    Has anyone else ever tried to cool their alternator in this manner? Are 308's infamous for frying failed alternators?

    Cheers - DM in Ohio
  2. M.James

    M.James F1 Rookie

    Jun 6, 2003
    Worcester, MA
    Full Name:
    Funny you should mention the VW link to this pipe....I spoke to a 'old school' Ferrari mechanic about this duct/tube (missing on my car) and he suggested to get one from a shop that works on old VW Beetles - the aluminum flexi-airtubes are identical in diameter. And Big-Time cheaper than OEM Ferrari replacements.

    I was told that this pipe was routed to hang over the rear brakes and keep them cool, versus the Cats/Exhaust. If you have an extra tube, I would be interested in purchasing it from you.
  3. MarkG

    MarkG Formula Junior

    Nov 3, 2003
    Colorado Springs
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    Re: alternator, I would be concerned about ducting debri and water into the alternator, but knowing how heat and electrical componants get along so well it is an interesting idea .......
  4. dave80gtsi

    dave80gtsi Formula 3
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    Nov 3, 2003
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    Dave Meredith
    Michael - Please reread my original post - The item I am discussing is indeed this same air-cooled VW Beetle aluminum flex hose which you mention, but it is NOT the same diameter. The Ferrari OE tube diameter is 2-1/2" (which apparently is an odd size, making it a bit hard to find), and the common VW replacement is instead 2". The whole point of my posting is to confirm for you all firsthand that the inexpensive smaller diameter tube works just fine as a substitute!

    You don't need to obtain a spare aluminum tube from me - that's the main reason that I took the effort to document the Whitney part numbers as a favor for you all, so that you could easily order direct from them!

    Finally, the purpose of this tube has nothing whatsoever to do with the rear brakes, as the brakes are not located near the welded tube holder on the rear passenger's side frame, which holds the tube and forces the air right onto the cat converters. Besides, any such hose at this general location would be only able to cool the brakes on the passenger's side of the car, not the drivers side, so you could potentially have uneven rear braking action if one were to try to cool just the passenger's side brakes. However, if you feel that you really do have a need for additional rear brake cooling on both sides, I suspect that you could improvise something easily enough here, using some additional tubing and perhaps a 2" diameter tube splice "Y" joint.


    Mark - Your comments about dirt and rain ducted onto the alternator are well reasoned, but recall that on most any conventional front engine car, the alternator is likely to be mounted somewhere near the front of the car and as such is automatically exposed to all sorts of incoming air, as well as its fair share of water and crud. It is this air flow which the 308 alternator location sorely lacks, since it is tucked tight between the engine block and the front header. Note that, on the 308, the passenger side air intake is the point of entry for this cooling air, and thus it's also the same entry point for air leading to the engine's throttle intake. A recent check of my engine's air filter does not show an unusual amount of dirt entering into it from this side scoop, so I suspect that I am good to go on that concern.

    Cheers - DM / Ohio
  5. Verell

    Verell F1 Veteran
    Consultant Owner

    May 5, 2001
    Groton, MA
    Full Name:
    Verell Boaen
    AutoZone also carries the 50mm x 533mm(~21") tube. It's a 'MIGHTY FLOW! preheater hose #96035. The one I have has a stick-on lable saying: DORMAN 708-009. Again, just $3 or so.

    I'm using a 2-1/2" flexible air duct (I think Mighty Flow again) to replace my tube. Just wish I knew what I did with my original tube when I pulled it off to do my timing bearings a couple of years ago. It's gotta be in the garage somewhere...

    BTW, the purpose of the tube is to bring cooling air into the area around the passenger side half-shaft & cool the tranny. As factory installed the tube is aimed at the half shaft's inner CV joint.

    3x8 alternators are known for dying because they've sucked oil into the slip rings.... Don't recall a post about one being fryed in the 4 years I've been lurking around the FChat.

    BTW, like most alternators, the blower on the front of the BOSCH alternators sucks air in at the back of the alternator. So your tube will have to stretch into the region behind the alternator.

    Starting about '84 the 308s started coming with a cast Al air plenum that covered the back of the alternator, and a flex tube that came out the back of the plenum & dropped down to suck cool air up from just at the level of the bottom of the car. This stops

    Guess it'll pull some dust, etc in if you're on a dirty road tho. Haven't heard of any problems.
    I'm in the process of retrofitting it on my '82 308. Am using a slightly different sized MIGHTY FLOW hose for it.

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