Trailer hitch on WRX... good or bad?

E

etittmann

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?
 
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?

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
 
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!!"
 
Al said:
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.

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

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.
 
Al said:
Can you pull a fuse and cut off the turbo for your haul?

Turbo is integral to the system. There is no separate fuse and
disabling it could do more harm than good.
 
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!!"

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.
 
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
unstable.

Cheers

Dave
 
@o13g2000cwo.googlegroups.com>,
(e-mail address removed) says...
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!!"

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
installed.
 
CompUser said:
Care to explain why Subaru markets a trailer
hitch for use on WRX's??

Bike racks? <G>

Very low profile tires would not also not give me the warm fuzzies when
thinking of towing with a WRX.
 
y_p_w said:
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.

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.
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.

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.
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.

Mine was an unmodified auto. Trips were in Sept. and May, North America.
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.

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
 
Al said:
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.

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.
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.

The turbo could be providing boost at higher normal freeway speeds.
Even if there's no boost, the turbo is working.
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?

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 said:
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.

Check out the original post!

Al
 
Al said:
Check out the original post!

Here's the original post (and my new comments):
I've put a trailer hitch on my 2004 WRX wagon, though I know that the
dealership does not recommend it.

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..........
I've heard this is due to the turbo, but I am unsure why this is
the case.

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.
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?

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
lbs.
I've heard if I do drive, I should drive at high rpms to reduce
strain on the engine. Does anyone have suggestions, thoughts?

You might want to go down a gear to prevent lugging of the engine
with the additional load.
 
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
lighter).

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.

Cheers,
Michael
 
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.

tia

Carl
 
The load ratings are probably low on the hi-po tires-- light car,
trailer and blowout no fun
 
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?


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. ;-)
 

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