I guess I probably picked the better model to tow close to the limit with. Roughly 7400lbs boat/trailer loaded. Triple Axle with electric brakes on two of those axles.

My question is how does it do? Do you tow with the PSM off so it holds a gear longer and starts in first? How about stopping with the electric brake control?

I shouldn't be towing very much (just long enough to get the burb painted and upgraded) and when I do it will be on mostly flat ground.

 

Gonna watch this thread. Want to pull a 6000# trailer with my S

 

Good news is I found out Boat/Trailer is 6950 not 7400. I should be well under the tow rating even with a full tank of fuel and gear.

I'll know how it does soon because I'm 95% sure I'm going to pull the trigger on this thing.

 

I have towed long distances with my two CTT (955 and 958). TT just gives better response, but all other systems (suspension, brakes, chassis, transmission) are going through the same stress.

Generally, you should look at 80% of the maximum tow rating as your safety net. However, the definition of what the tow rating is for a hauler is not standarized.

I have towed the same rig with a 3500 Cummins 2016 RAM and a 958TT, and the CTT tows much better (better braking, air suspension, acceleration too).

Key components are an extra (aftermarket) transmission cooler and a rear differential cooler.

For boats, consider fuel load in the boat, a 200 gallons tank adds almost 1,300 lbs. For a 7000 lbs boat/trailer, I would get a spare dedicated 3/4 or 1-ton used pickup.

 

I have a '05 CTT. I also tow near (possibly slightly over) the limit. My trailer is a 20' enclosed trailer (#3,550) with my 928 track car (#3,000) plus tools, tires, and other crap.

I've gone from Detroit to VIR, Road America, Mid-Ohio, etc and the car has always performed well.

As to the PSM question. I generally leave it on (enabled), but it depends. From a full stop, I will often deactivate it so I get 1st gear starts. Also if I'm climbing hills like crossing WV on my way to VIR. Otherwise I usually leave it enabled. If I'm rolling on a relatively flat stretch, it will often drop to 6th gear, but stay in boost. Car seems to be happy.

I generally get around 9.0 MPG with this setup. Best I've done is 9.5. I generally keep it between 65 and 70. The MPG penalty is high as I go over 65, with little gained. I'm not sure if the GTS will behave similarly, but at least you have a data point to go on.

 

I’ve probably done 5000 miles towing 6,000 lbs. I leave PSM on and use the steering wheel to shift to 1st to get moving. No issues. Tows great.

I average 10.5 on the highway.

 

Maybe I'm missing something, but why would you want PSM off when towing? PSM helps with traction / stability, and will reduce wheel spin. It doesn't increase torque or mess with throttle mapping / gear selection though. Are people confusing PSM with Sport Mode?
In sport mode it will hold gears longer, give a sensation of more power/torque by changing throttle map, etc. I wouldn't recommending towing with PSM off ever... if you're braking on a downhill curve, with a heavy trailer behind you, on some wet leaves, and maybe your electric brake controller isn't quite set right for the weight of the load... believe me, you'll want the computers to do everything they possibly can to bail you out. PSM is your friend. It may get in the way on the track when you want to intentionally exceed the yaw limit and let the tail hang out some... but on a tow vehicle? Leave the button alone.
Or, as I said, maybe I'm missing something here

 

I just finished 12 months towing a 6,740 lb Airstream all over the place with my 2006 CS. First leg was up the west coast, Olympic, Glacier and Yellowstone Nat'l Parks. Then down to the Utah and AZ parks. Layover in AZ Nov - Jan then 1,000 miles down the Baja peninsula to Cabo. Then back to Bay Area and north to Banff and Jasper. Then mile zero of the Alaska highway and into Alaska for five weeks. Then back along the Marine Highway to Vancouver Island and down the west coast.

Every time we pulled into an RV park, someone came over with the comment 'you tow that with that?'. I loved it

We put 27,000 miles on the CS of which about 23,000 were towing miles. Absolutely no issues and no aftermarket add-ons. 100% stock.

No problems with the mountains either and I went over them at the limit, not is the slow lane with the diesels. Depending on the grade, I ran as low as 3rd gear to generate power but rarely over 4,000 rpm. I monitored the coolant temp with my OBD reader and the highest value I saw was 221F going up the long I-5 pass in Oregon when it was 103F out.

Here's a pic of our camp in Homer, Alaska where you can see the relative size of our Cayenne and Airstream. Lots of pics and details on our travel blog at www.dcairstream.net. If you are scroll down and hit the June archive, you'll see the Alaska pics. Baja was last Feb.

Any questions?

 

Early Cayenne’s didn’t have sport mode. So the only way to get the transmission to shift into first gear automatically from a standstill is to turn off PSM.

I choose to leave PSM on for stability, and manually select first gear when needed.

 

pics,I towed over #7,000 with my 06 **** but not over &0mph

 

PSM off completely changes the shift mapping in the GTS. It holds the gear higher than sport on does, doesn't prematurely upshift no matter what the throttle position, AND actively downshifts when you let off the throttle to slow the vehicle down without using brakes. It's shift pattern is almost exactly that of a tow/haul button in a 3/4-1 ton truck or how someone would shift with a manual trans when towing. For example, loafing around in traffic at 35-40 mph PSM off will hold 4th gear indefinitely, where sport and regular modes will both hunt from 4th to 6th.

I really don't like the idea of turning PSM off because of the stability control aspect, especially with such a heavy boat, but I figured I'd ask anyways. Will probably just throw it into manual mode and shift it that way.

I'm really most interested in how it handles the movement of the trailer side to side, but with guys having no issues with enclosed trailers, I doubt I will with a boat. The enclosed trailers I've towed in the past have been worse about getting blown around on the road than boats. I've also never pulled a triple axle with anything so I'm sure that changes the dynamic too.

 

Woa! AWESOME shot. This is exactly the kind of thing I needed to know.

 

Any updates on Towing with the GTS?

 

I didn't buy the boat, but when I towed it to the ramp for a water test the Cayenne didn't even break a sweat. Kept PSM on and had the suspension in low height/normal dampening mode, let it shift on it's own until I hit traffic then manually shifted. The rig was right close to the tow rating and you could tell you had a load on it, but no issues or surprises in the 15 or so miles I had it on the road. Stopped ok, no sway or other nonsense at 70mph, easily accelerated quick enough to keep up with the flow of traffic, which I'm sure the 4.10 gears helped with compared to whats in the S/Turbos. I was pretty impressed. FWIW- I tow my smaller boat @2000ish lbs all over the place and I forget it's even back there most of the time.

 

Awesome, good to hear. I have a little ski boat, about 4,000 lb including the trailer. I imagine the GTS would tow it just fine then. Do you need a brake controller?