Trailer hitch on WRX... good or bad?

Discussion in 'Subaru Impreza' started by etittmann, Jul 10, 2005.

  1. etittmann

    etittmann Guest

    Hello all,
    I've put a trailer hitch on my 2004 WRX wagon, though I know that the
    dealership does not recommend it. I've heard this is due to the turbo,
    but I am unsure why this is the case. If I haul a boat (not a huge
    one--outboard motor on an aluminum boat, not sure the weight) twice a
    year for 3 hours, is this potentially damaging to the motor? I've
    heard if I do drive, I should drive at high rpms to reduce strain on
    the engine. Does anyone have suggestions, thoughts?
    etittmann, Jul 10, 2005
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  2. etittmann

    Al Guest

    My '95 Outback had an included hitch. It was the 2.5 liter engine
    (non-turbo). I pulled a loaded U-Haul 700 miles twice a year when my son
    was going to college. I have had no problems.

    Since turbos come into play only with spirited driving, they are used
    for short bursts of power. Perhaps if the turbo is running without
    stopping due to the load, it will fry.

    Can you pull a fuse and cut off the turbo for your haul?

    Al, Jul 10, 2005
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  3. etittmann

    jabario Guest

    WRX's are not for towing. I'd say if you used the hitch for a bike
    rack no problem but I wouldnt tow with a turbo. When something goes it
    will be easy for dealer to see the hitch and say "engine /turbo/widget
    burned out from towing-- No warranty!!"
    jabario, Jul 10, 2005
  4. etittmann

    y_p_w Guest

    Turbos can typically handle extended use. Turbos have been used to
    boost the performance of diesel tractor engines and high-performance
    aircraft engines for years. In those applications, they're counted
    on to perform reliably for long stretches of time.

    A highway cruise at 3000+ RPM would likely mean the turbo is delivering
    boost. Even without any boost, the exhaust pressure is driving the
    turbo. The WRX has a standard oil to coolant heat exchanger - i.e. oil
    cooler - which should keep oil temps down.
    Why? Having the turbo to help with power/torque is a good thing. The
    biggest problem may be with the transmission overrheating. The manual
    tranny doesn't have a cooler; don't know about the auto.

    I'd think that turning off the turbo might overstress the engine given
    the additional load. Without the turbo, it's a low-compression (8:1)
    DOHC engine which you might need to rev higher.
    y_p_w, Jul 11, 2005
  5. etittmann

    y_p_w Guest

    Turbo is integral to the system. There is no separate fuse and
    disabling it could do more harm than good.
    y_p_w, Jul 11, 2005
  6. etittmann

    y_p_w Guest

    There is a tow rating in the owner's manual - 1000 lbs w/o brakes and
    2000 lbs w/ trailer brakes. It's reduced for AT with any uphill grades.
    However - it does state that "damage or malfunction caused by towing"
    isn't covered by the warranty.

    It's basically - do it if you feel like it, but if you toast your
    transmission we're not paying for it.
    y_p_w, Jul 11, 2005
  7. etittmann

    Coggo Guest

    I have a Forester GT Turbo 2 litre with AT (in Australia). I have towed a
    braked trailer (a caravan) which weighs about 2000 lbs with the Forester for
    over 1500 miles (Brisbane to Sydney and return). I had an transmission oil
    cooler fitted, and there were no apparent problems with the engine or
    transmission at all - in fact it ran cool and went like a rocket. After the
    trip, the AT fluid was a little bit darkened so I changed it as a
    precaution, but I think that there is a over-temperature alarm in the AT if
    it runs too hot anyway. However, I wouldn't do that again, because the car
    is a bit light for that sort of weight behind it, and it felt just a bit


    Coggo, Jul 11, 2005
  8. etittmann

    CompUser Guest>,
    Care to explain why Subaru markets a trailer
    hitch for use on WRX's??

    In fact, they even mention that the SPT exhaust
    won't fit on a WRX if the Subaru trailer hitch is
    CompUser, Jul 11, 2005
  9. etittmann

    B a r r y Guest

    Bike racks? <G>

    Very low profile tires would not also not give me the warm fuzzies when
    thinking of towing with a WRX.
    B a r r y, Jul 11, 2005
  10. etittmann

    Al Guest

    They were designed for that purpose, i.e., heavy duty! Ever see the
    price of a general aviation turbo charged engine? You could buy a couple
    of Subarus for that price.
    If the engine needs a turbo boost at highway speeds, in my opinion,
    something is wrong. After all the 2.5L worked fine under my towing
    conditions and without a turbo.
    Mine was an unmodified auto. Trips were in Sept. and May, North America.
    Pulling the trailer, my Subaru downshifted only when going up steep (for
    my area) hills in Connecticut on route 84.

    So why the reported prohibition on towing with the turbo 2.5?

    Al, Jul 11, 2005
  11. etittmann

    y_p_w Guest

    The turbo is always spinning when there's exhaust pressure. It's
    supposed to be ready when needed. There's no way to disengage it.

    You make it sound like a passenger car turbocharger is some delicate
    instrument that needs to be used sparingly to avoid self-destruction.
    It's meant to be used.
    The turbo could be providing boost at higher normal freeway speeds.
    Even if there's no boost, the turbo is working.
    What prohibition? I've got a 2004 WRX manual, which includes the
    STi information. It only mentions that towing isn't recommended,
    but then sets absolute limits for towing weight.
    y_p_w, Jul 11, 2005
  12. etittmann

    Al Guest

    Check out the original post!

    Al, Jul 11, 2005
  13. etittmann

    y_p_w Guest

    Here's the original post (and my new comments):
    A dealership is not likely to recommend it. The manual does not
    recommend it. The WRX was never designed with towing in mind. That
    being said, the owner's manual goes on to outline steps that need to
    be taken if you insist on towing, and gives absolute weight limits
    for trailer/load weights. Not recommended, warranty in jeopardy,
    but if you insist..........
    The turbo and engine should be able to handle it fine. Typical
    freeway speeds result in a relatively low level of boost anyways.
    Regardless of whether or not the ECU opens up the boost, your turbo
    is constantly churning. However - your owner's manual does have
    additional recommended motor oil viscosities for towing use.
    Like I said before, I'd worry less about the motor and more about
    the transmission. Let's see... A "deluxe" 14 ft aluminum boat
    with a 20 HP engine weighs about 275lbs. The trailer is maybe 200
    You might want to go down a gear to prevent lugging of the engine
    with the additional load.
    y_p_w, Jul 11, 2005
  14. I have a 2004 Turbo Forester and I see no such entry in my manual. I
    tow a trailer (up to about 1200#)) often with it and it performs just
    fine. I suspect that it's more a weight issue (the WRX being

    My only complaint is the Subaru factory tow hitch is a bit whimpy.
    I'll be looking for a better aftermarket hitch at some point.

    Lord Drool Rockworm, Jul 11, 2005
  15. A little OT but, what combos of perf mufflers and hitches (Sube or
    aftermarket) do work together?
    I may want to do this very thing soon.


    Carl 1 Lucky Texan, Jul 11, 2005
  16. etittmann

    jabario Guest

    The load ratings are probably low on the hi-po tires-- light car,
    trailer and blowout no fun
    jabario, Jul 11, 2005
  17. etittmann

    Mark IV Guest

    And why the heck not?
    Mark IV, Jul 13, 2005
  18. etittmann

    nothermark Guest

    Drive with the engie running comfortably. Don't load the boat with a
    half ton of "stuff". Don't pick the hottest day of the year. Pick
    your route to minimize steep grades. A long flat route beats a short
    steep one.

    There are several areas of concern. Lugging the engine will strain
    the crankshaft bearings. High loads strain the transmission and/or
    clutch. The brakes may be an issue. The attachment points to the car
    may be an issue. The Turbo increases the power available so it
    increases the stress you can create in these areas. Be sensible,
    avoid high speed downhill runs where you might have to stop in a
    hurry, you won't be able to. ;-)
    nothermark, Jul 13, 2005
  19. etittmann

    jabario Guest

    Turbo jerks and will damage components when confronted with an xtra
    jabario, Jul 13, 2005
  20. etittmann

    CompUser Guest

    You won't be getting any kind of logical answer
    CompUser, Jul 13, 2005
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