SubOperator Posted June 13, 2017 Share Posted June 13, 2017 the HDCVT fails when the USDM wrx gets stage 2 tuning. this is confirmed multiple times on nasioc and is the reason why Cobb wont make a stage 2 map for CVT WRX's. Stage 1, or about 300 crank hp/tq is about the safe limit for those boxes. So the box is at its limit at 300hp and then you want to put it in a 4500lb SUV that im sure people will want to use for some tow duty, instead of a 3300lb car. Kaboom Yup. Hence my plan to wait out some time. 2005 LGT Wagon Limited 6 MT RBP Stage 2 - 248K 2007 B9 Tribeca Limited DGM - 258K SOLD - 2005 OB Limited 5 MT Silver - 245K SOLD - 2010 OB 6 MT Silver - 205K Link to comment Share on other sites More sharing options...
SBT Posted June 16, 2017 Author Share Posted June 16, 2017 the HDCVT fails when the USDM wrx gets stage 2 tuning. this is confirmed multiple times on nasioc and is the reason why Cobb wont make a stage 2 map for CVT WRX's. Stage 1, or about 300 crank hp/tq is about the safe limit for those boxes. So the box is at its limit at 300hp and then you want to put it in a 4500lb SUV that im sure people will want to use for some tow duty, instead of a 3300lb car. Kaboom That's 4500 lb vehicle plus 1120 (160lb average person/luggage X 7 seats ) plus 3500 lb towing = >9,100 lbs. More in 8-passgenger configuration. Ugh! - Pro amore Dei et patriam et populum - Link to comment Share on other sites More sharing options...
whitetiger Posted June 16, 2017 Share Posted June 16, 2017 yeah, I didnt even think of fully loaded weight. Link to comment Share on other sites More sharing options...
SubieDriver Posted June 16, 2017 Share Posted June 16, 2017 That's 4500 lb vehicle plus 1120 (160lb average person/luggage X 7 seats ) plus 3500 lb towing = >9,100 lbs. More in 8-passgenger configuration. Ugh! People (me included) have been desiring more than 3500 lbs towing. The Audi Q7 tows 6600 lbs (but you get a 3.0 turbo 6 in it, instead of a turbo 4). I would really like to see a turbo six as an option in the Ascent. Link to comment Share on other sites More sharing options...
SBT Posted June 17, 2017 Author Share Posted June 17, 2017 MAZDA CX9 - 2.5L I4T (250HP/310TQ) GCWR 4327, AWD towing is 3500 FORD EXPLORER - 2.3L I4 EcoBoost (280HP/210TQ) 8,150 GCWR, AWD 3:51 Final Drive. Towing 3000 lbs w/Class II Trailer Package - 3.5L V6 (290HP/255TQ) 7,110 GCWR, AWD 3.65 Final Drive. Towing 2000 lbs w/dealer installed Class I hitch package 10,150 GCWR, AWD 3.39 Final Drive. Towing 5000 lbs w/Class iII hitch. - 3.5l V6 EcoBoost (365HP/350TQ0 10,400 GCWR, AWD, 3.16 Final Drive. Towing 5000 lbs w/Class III hitch TOYOTA HIGHLANDER - 3.5L V6 D4S (295HP/263TQ) 6,000 GCWR, AWD, 3.003 Final Drive. Towing 5000 lbs w/Class III hitch HONDA PILOT - 3.5L V6 (280HP/262TQ) 4,330 CW, AWD, 4.334 Final Drive. Towing 5000 lbs w/Class III - Pro amore Dei et patriam et populum - Link to comment Share on other sites More sharing options...
FLlegacy Posted June 18, 2017 Share Posted June 18, 2017 People (me included) have been desiring more than 3500 lbs towing. The Audi Q7 tows 6600 lbs (but you get a 3.0 turbo 6 in it, instead of a turbo 4). I would really like to see a turbo six as an option in the Ascent. I don't believe having a bigger engine is going to get you more towing capacity, the chassis, brakes, and cooling capacity will decide what subaru will warranty as a towing capacity. If you really need to tow that much weight you should consider a custom outfitter to get the Ascent up to the task, or get a suitable tow vehicle. I personally wouldn't want a 6k lb trailer behind my 4.5k lb family hauler and the length will make sway control a must. There is a reason trucks weigh over 6k lbs. Link to comment Share on other sites More sharing options...
FLlegacy Posted June 18, 2017 Share Posted June 18, 2017 MAZDA CX9 - 2.5L I4T (250HP/310TQ) GCWR 4327, AWD towing is 3500 FORD EXPLORER - 2.3L I4 EcoBoost (280HP/210TQ) 8,150 GCWR, AWD 3:51 Final Drive. Towing 3000 lbs w/Class II Trailer Package - 3.5L V6 (290HP/255TQ) 7,110 GCWR, AWD 3.65 Final Drive. Towing 2000 lbs w/dealer installed Class I hitch package 10,150 GCWR, AWD 3.39 Final Drive. Towing 5000 lbs w/Class iII hitch. - 3.5l V6 EcoBoost (365HP/350TQ0 10,400 GCWR, AWD, 3.16 Final Drive. Towing 5000 lbs w/Class III hitch TOYOTA HIGHLANDER - 3.5L V6 D4S (295HP/263TQ) 6,000 GCWR, AWD, 3.003 Final Drive. Towing 5000 lbs w/Class III hitch HONDA PILOT - 3.5L V6 (280HP/262TQ) 4,330 CW, AWD, 4.334 Final Drive. Towing 5000 lbs w/Class III I find it very interesting the Highlander can tow 5k lbs with awd but the Sienna with the same brakes, engine, transmission, awd system, and built on the same platform is only rated at 3500. Link to comment Share on other sites More sharing options...
ehsnils Posted June 18, 2017 Share Posted June 18, 2017 I find it very interesting the Highlander can tow 5k lbs with awd but the Sienna with the same brakes, engine, transmission, awd system, and built on the same platform is only rated at 3500. Marketing decision. Link to comment Share on other sites More sharing options...
SBT Posted June 18, 2017 Author Share Posted June 18, 2017 I find it very interesting the Highlander can tow 5k lbs with awd but the Sienna with the same brakes, engine, transmission, awd system, and built on the same platform is only rated at 3500. Probably has something to do with the Van vs SUV chassis setup, engine and transmission cooling. - Pro amore Dei et patriam et populum - Link to comment Share on other sites More sharing options...
SubieDriver Posted June 18, 2017 Share Posted June 18, 2017 I find it very interesting the Highlander can tow 5k lbs with awd but the Sienna with the same brakes, engine, transmission, awd system, and built on the same platform is only rated at 3500. It has to do with AWD vs FWD. When looking at the Hyundai Santa Fe a couple years ago, the FWD version was rated at 3500 lbs, while the AWD version was 5000 lbs. Link to comment Share on other sites More sharing options...
SBT Posted June 18, 2017 Author Share Posted June 18, 2017 I thought that as well, but the FWD and the AWD Highlander with V6 are rated at 5000 lbs towing. - Pro amore Dei et patriam et populum - Link to comment Share on other sites More sharing options...
FLlegacy Posted June 19, 2017 Share Posted June 19, 2017 I thought that as well, but the FWD and the AWD Highlander with V6 are rated at 5000 lbs towing. And the Sienna is available in awd. Sent from my SAMSUNG-SM-G920A using Tapatalk Link to comment Share on other sites More sharing options...
ehsnils Posted June 19, 2017 Share Posted June 19, 2017 So I still think it's a marketing decision. But it can also be a weight saving on the Sienna making it weaker in the rear end and not allowing the same strength for a trailer. Link to comment Share on other sites More sharing options...
SBT Posted June 19, 2017 Author Share Posted June 19, 2017 Towing 5,000 lbs, on a uni-body chassis (which all of these mid-SUVs are), does not do the vehicle any favors. The torsional flex with these kinds of loads can be substantial and they can compromise both the chassis and occupant safety if the vehicle, and the towed-rig, is not setup and handled properly. Proper equipment and training is key to any successful tow, but how many really think about the impact and the safety risks? My observation is that it's become a "it's got a 'hitch' so let's go hook-up and tow something" mentality. I've regularly towed between 1,000 and 12,000 lbs. From about 3,500lbs and up, you notice the changes in handling, braking, drivetrain loading, and the amount of sideways "push" especially with lighter vehicles like mid-SUVs. You notice it, but nearly as much with a 7,500lb truck that's setup for towing, even with the heavier, 10,000+ lbs. It's all speculation until it's in production, but I'm sure, Subaru, in their typical, over-engineered, way, will look at all of these factors and establish a 'limit' that's both safe and reasonable. - Pro amore Dei et patriam et populum - Link to comment Share on other sites More sharing options...
dga Posted June 22, 2017 Share Posted June 22, 2017 On all of these, their main limitation is the unibody. Take a look at the towing rating of Ridgeline and why it's only 5,000 while it's payload capacity beats certain trucks in it's class. Also 4500 lbs. SUV has more than enough weight to tow 5,000 lbs. of anything. I have an old '96 GMC K1500 extra cab, long bed, with heavier tow package axle, etc., and it weighs in at almost exactly 5,200 lbs. That is not much more and it's rated to tow about 7,500 lbs. With a properly loaded trailer the SUV's can tow without any issues what so ever. Link to comment Share on other sites More sharing options...
FLlegacy Posted June 22, 2017 Share Posted June 22, 2017 On all of these, their main limitation is the unibody. Take a look at the towing rating of Ridgeline and why it's only 5,000 while it's payload capacity beats certain trucks in it's class. Also 4500 lbs. SUV has more than enough weight to tow 5,000 lbs. of anything. I have an old '96 GMC K1500 extra cab, long bed, with heavier tow package axle, etc., and it weighs in at almost exactly 5,200 lbs. That is not much more and it's rated to tow about 7,500 lbs. With a properly loaded trailer the SUV's can tow without any issues what so ever. You also have to take into account the wheel base for a truck is significantly longer than most SUVs to provide stability when towing large trailers. And most of the trucks weight is over the front axle leaving the rear plenty of capacity for a heavy trailer. Link to comment Share on other sites More sharing options...
dga Posted June 22, 2017 Share Posted June 22, 2017 You also have to take into account the wheel base for a truck is significantly longer than most SUVs to provide stability when towing large trailers. And most of the trucks weight is over the front axle leaving the rear plenty of capacity for a heavy trailer. Good point, but a slight counterpoint. The length of the wheelbase being less important as max payload trucks tend to be single cab duallies, shortest of the bunch. Also you can only put some much tongue weight on to the truck before the front wheels are merely a suggestion in which direction the truck is moving. I think a significant amount of trailering capability rests in the suspension and an SUV being a huge compromise in nearly every department, they will not sacrifice ride and handling for a somewhat greater payload. Link to comment Share on other sites More sharing options...
SBT Posted June 22, 2017 Author Share Posted June 22, 2017 Where trucks have the distinct advantage, is their ability to site a fifth-wheel hitch, or even a gooseneck ball on, or ahead of, the rear axle, thereby increasing/spreading the load over more of the chassis and the suspension, increasing directional stability, and increasing load-carrying capability. Given that a Mid-SUV will always be setup as a tow-at-the-rear-hitch, they do give up directional stability as tongue-loading increases. As Ford mentions about the Explorer, their 3,500 and 5,000lb tow capacity, must be done with a Class II or III load-leveling hitch, respectively. Look for other manufactuers to adopt similar restrictions. I always cringe when I see any FWD vehicle (van/suv/cuv, etc.) towing a heavy-ish trailer, where the rear is loaded to the point that the rear wheels are cambered-in to near the stops, and there's an obvious large gap between the front wheels and the fender edge. All clear signs that the front wheels are not effectively engaged and able to properly do their job. Even the Mazda review that i posted mentioned that the AWD CX9, which is a FWD with AWD add-on, started to lose traction as tongue and trailer weight increased - even below rated capacity. - Pro amore Dei et patriam et populum - Link to comment Share on other sites More sharing options...
FLlegacy Posted June 24, 2017 Share Posted June 24, 2017 Good point, but a slight counterpoint. The length of the wheelbase being less important as max payload trucks tend to be single cab duallies, shortest of the bunch. Also you can only put some much tongue weight on to the truck before the front wheels are merely a suggestion in which direction the truck is moving. I think a significant amount of trailering capability rests in the suspension and an SUV being a huge compromise in nearly every department, they will not sacrifice ride and handling for a somewhat greater payload. Max payload decreases as the weight of the cab and chassis increases, the axles and springs are rated for a certain amount of weight as are the tires. The weight limit is irregardless of cab configuration or drive configuration. And even the most stripped down of trucks is as heavy as an SUV and usually with a longer wheelbase. SUVs are not built for towing like a truck is, they simply have the ability. It isn't the main focus, trucks are built foremost for utility so it makes sense they would be more capable but less comfortable. For the same dollars you wont find an SUV than can out-tow a truck, or a truck that is better suited to hauling around a family than an SUV. Link to comment Share on other sites More sharing options...
Opie Posted June 24, 2017 Share Posted June 24, 2017 there is still the autobox problem. Until Subaru comes out with a auto that can handle over 300hp/tq, all this engine speculation is just that. The current HT-CVT can handle the power, if it is properly cooled. Which it is not in any of it's current applications. Link to comment Share on other sites More sharing options...
SBT Posted June 24, 2017 Author Share Posted June 24, 2017 You're talking about a lot of line pressure with Subaru's CVTs > !,000PSI. Is that one of the reasons it's not installed/available in towing models? - Pro amore Dei et patriam et populum - Link to comment Share on other sites More sharing options...
FLlegacy Posted June 25, 2017 Share Posted June 25, 2017 The line pressure isn't that high just the internal pressures. Can you imagine finding a radiator that could withstand 1000psi... Sent from my SAMSUNG-SM-G920A using Tapatalk Link to comment Share on other sites More sharing options...
SBT Posted June 25, 2017 Author Share Posted June 25, 2017 Seems like there is an engineering concern about connecting an external cooler to the CVT - are substantial fluid pressures part of that? - Pro amore Dei et patriam et populum - Link to comment Share on other sites More sharing options...
FLlegacy Posted June 25, 2017 Share Posted June 25, 2017 Internal chain tension is where the high pressure comes into play, the diagram from the fsm for the cooling system is the same as any other automatic. The line pressure is most likely the same or slightly higher than a traditional automatic. The oil in the cooler circuit is simply being circulated for cooling purposes it is not in concert with the internal transmission pressures. Also of note is the outback comes with an external oil to air cooler so there are auxiliary coolers for the cvt.cvt cooler.pdf Link to comment Share on other sites More sharing options...
SBT Posted June 25, 2017 Author Share Posted June 25, 2017 I checked the 2017 specs for the OB both with 2.5 and 3.6 and couldn't find a standard (or optional) trans oil cooler water or air cooled. - Pro amore Dei et patriam et populum - Link to comment Share on other sites More sharing options...
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