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Supercharged111's avatar
Supercharged111
Explorer
Jun 10, 2013

GM GVWR/GCWR chassis/powertrain questions

Starting to do my research here, but it seems very few people ask the questions that I do. I'm indifferent to class A vs class C, I'm after something no bigger than 25' and I'm sure either can accomodate my needs as far as amenities go. I want to pull my car to the track as I do behind my pickup now, but this way to have a place to sleep if the weather is hot/humid, rainy, etc. This will also enable me to make this a family event and not just me disappearing for the weekend.

At any rate, onto the questions. I love to wrench, so that's what my questions are geared toward. What are the GVWRs and GCWRs of some common GM chassis? I'm inclined to thinking that the chassis are pretty much all the same, with a camper slapped on the back of a cutaway van (so the camper part is the variable). The Fords wear an E450 badge on the side, so they're easy to spot, but I'm starting to doubt GM ever gave up anything heavier than a 3500 chassis to a class C motorhome? I know they did 4500 chassis, but my fruitless google searches seem to indicate that they all went to the topkicks/kodiaks, and perhaps the class A motorhomes? If only a 3500 chassis, is that a 12,000# GVWR? What's a camper typically weigh? I don't want to cross the scales overloaded pulling a car trailer and I'm not looking at newer motorhomes either, just something new enough to have overdrive. I can get the power from the motor eventually, which leads me to my next question: when not pulling a car trailer, how well do these behemoths hold OD? I live in CO where the air is thin, and my truck needed a little help performing up here so I imagine an inverted sail is no different.
Class C

19 Replies

  • Supercharged111's avatar
    Supercharged111
    Explorer
    Jun 11, 2013
    http://denver.craigslist.org/rvs/3827500261.html

    I'm really digging this one, it has a nice short ass. Just a matter of what's leftover for GVWR/GAWR once a trailer gets hooked up. For Cs, I think I'm here or slightly larger E-450. It's a little pricey IMO, but that's the body I'm after.
  • carringb's avatar
    carringb
    Explorer
    Jun 11, 2013
    Supercharged111 wrote:
    Alright, now I feel a bit more edumucated and better armed since I don't need to search for something that doesn't exist. Curb weights are what will kill me though, not knowing how much is "leftover" on a given unit I might check out. Are there any MH in particular to watch for that have a little leftover (besides the smallest E-450 I can get my hands on)? My thought was if the 22' MHs have the same GVWR as the 25 footers, I'd have a little more wiggle room, right? Or are their GVWRs conveniently lower as well as a lot have small blocks? It's becoming more and more obvious that MH manufacturers try to get the cheapest chassis possible and load it as full as possible of goodies since that's what sells, can't really blame them. Should I be looking at class A's too? I'm shocked on some of those at just how much camper they'll put on top of a gas engine.

    EDIT: In search for GVWRs, I came across this. The hood looks funny, so I wonder if it's the 94-96 body style you mentioned despite its short wheelbase.

    http://www.commercialtrucktrader.com/find/listing/CHEVROLET-G30-109030842


    Yeah, that's the chassis. But you are right, the RV makers like to go as small as feasible on a chassis. I have never seen a smaller MH on the G-30 HD, unlike some of the smaller E450s.

    BTW - a longer (28'-ish) E450 with no slides can still have good payload. I've seen some with over 3,000 pounds of carrying capacity.

    Another thing to consider is the GCWR (c=combined). The E450 will have a 20,000# GCWR in that era. The G30 will only have about a 16,000# GCWR, which makes sense given its 230 HP.
  • Supercharged111's avatar
    Supercharged111
    Explorer
    Jun 11, 2013
    Alright, now I feel a bit more edumucated and better armed since I don't need to search for something that doesn't exist. Curb weights are what will kill me though, not knowing how much is "leftover" on a given unit I might check out. Are there any MH in particular to watch for that have a little leftover (besides the smallest E-450 I can get my hands on)? My thought was if the 22' MHs have the same GVWR as the 25 footers, I'd have a little more wiggle room, right? Or are their GVWRs conveniently lower as well as a lot have small blocks? It's becoming more and more obvious that MH manufacturers try to get the cheapest chassis possible and load it as full as possible of goodies since that's what sells, can't really blame them. Should I be looking at class A's too? I'm shocked on some of those at just how much camper they'll put on top of a gas engine.

    EDIT: In search for GVWRs, I came across this. The hood looks funny, so I wonder if it's the 94-96 body style you mentioned despite its short wheelbase.

    http://www.commercialtrucktrader.com/find/listing/CHEVROLET-G30-109030842
  • carringb's avatar
    carringb
    Explorer
    Jun 10, 2013
    Supercharged111 wrote:
    carringb wrote:
    BTW - the Chevy Express 4500 chassis is very rare because GM put it on hold for a few years after Workhorse badging stopped (that only went on a couple years too). Even with the DuraMax, the Express does not have the Allison. Also I don't GM offers the RV-prep package with the DuraMax 4500.


    This is still newer than I'm after, early 2000s is it for me and only if it's priced right. I can't seem to determine if GM ever made a G40? I guess that's what I'd be after, whatever predates the Express chassis. I've seen a couple 22 footers that might do the trick, but as expected they don't all have big blocks. Now to determine the GVWR of those and their respective wheelbases. Seems pretty obvious that an E-450 or E-Super Duty is up to the task, but I can't have anything older than 2000 right? For fear of shooting a plug out.


    Got it. You are right, the Express 4500 didn't come out until 2012, except for the short run "Workhorse" 4500s around '08.

    GM did make a cutaway called the G35HD, which was really just a P30 chassis with a van cab (old body style) and a tilt hood. I think this sold from '94-'96. It had a 14k GVWR. But I'm not sure you'll find it under anything but a 30'.

    Even though the first gen V10 was more likely to spit a plug, it still wasn't common. But it also had less HP which is the better reason IMO to hold out for a 2000+ E450.
  • pnichols's avatar
    pnichols
    Explorer II
    Jun 10, 2013
    Just as a reminder - you need year 2005 on up of the Ford E350 or E450 chassis to get the TorqueShift computer controlled 5-speed TOW/HAUL transmission.
  • Supercharged111's avatar
    Supercharged111
    Explorer
    Jun 10, 2013
    carringb wrote:
    BTW - the Chevy Express 4500 chassis is very rare because GM put it on hold for a few years after Workhorse badging stopped (that only went on a couple years too). Even with the DuraMax, the Express does not have the Allison. Also I don't GM offers the RV-prep package with the DuraMax 4500.


    This is still newer than I'm after, early 2000s is it for me and only if it's priced right. I can't seem to determine if GM ever made a G40? I guess that's what I'd be after, whatever predates the Express chassis. I've seen a couple 22 footers that might do the trick, but as expected they don't all have big blocks. Now to determine the GVWR of those and their respective wheelbases. Seems pretty obvious that an E-450 or E-Super Duty is up to the task, but I can't have anything older than 2000 right? For fear of shooting a plug out.
  • pnichols's avatar
    pnichols
    Explorer II
    Jun 10, 2013
    I only tow lightly with my V10 (aluminum boat). But I can tell from how it drives and "feels" that it has way more power available than I have to tap into.

    Note that the Ford V10 is a different kind of truck engine from the big old relatively low RPM thumping V8's most of us were raised on. It's a high RPM truck engine so you have to wind it up to tap it's horsepower - which then gets converted into torque at the rear wheels. It's common to run V10s on long pulls up steep mountain grades at 4500 RPM or higher for long periods of time. Many folks are not used to this so they think that diesels of around the same equivalent horsepower "pull better" just because diesels develop their horsepower at lower engine RPMs. Ford takes care of overall vehicle gearing in the E450 chassis so that their V10 high RPM horsepower gets converted into all the torque to the ground needed at the rear wheels. The V10 is at the same time very durable ... with many private and commercial owners reporting usable life in the 400,000 to 500,000 mile range.

    Search these forums for much more info on the Ford V10 - what it can do. Here's a typical discussion thread on V10 performance partially related to what you're investigating - but there are many more discussions in the forums, including those specific to it's raw towing ability if you drive it right:

    http://www.rv.net/forum/index.cfm/fuseaction/thread/tid/26999653/srt/pa/pging/1/page/1.cfm
  • carringb's avatar
    carringb
    Explorer
    Jun 10, 2013
    BTW - the Chevy Express 4500 chassis is very rare because GM put it on hold for a few years after Workhorse badging stopped (that only went on a couple years too). Even with the DuraMax, the Express does not have the Allison. Also I don't GM offers the RV-prep package with the DuraMax 4500.
  • carringb's avatar
    carringb
    Explorer
    Jun 10, 2013
    Supercharged111 wrote:
    My concern is how much power is unlocked with bolt-ons on the V10? How durable are the transmissions when you start adding power and beating on them? It takes a lot to push something like that through the wind at altitude with a trailer at 70-75mph (interstate speed limit here is 75mph and trucks don't have a separate limit, I really don't think 60-65 would be a great idea and I doubt I have the patience to go that slow),


    The V10 has lots more power hidden in it. I have the full Banks PowerPack, AFE Stage-2 intake, and a Diablo Predator tuner (if I bought a new programmer, I would go would 5-star instead).

    You will have no problem going 70-75, however it will burn fuel very fast at those speeds. Also in the summer you may have to start watching tire temps at higher speeds.

    My transmission is still original, other than the Banks TransCommand module. Ditto the engine. I have 354,000 miles in in now. About 200,000 of that is towing heavy (ave ~ 22,000 combined), and another 120,000 or so fully loaded but without a trailer.
  • Supercharged111's avatar
    Supercharged111
    Explorer
    Jun 10, 2013
    Yeah, that 5 speed sure is enticing but now we're talking $20k+. Finding these class C GM4500 chassis is proving to be a real pain in the ass. I'm having a low percentage of success on my google searches, but I did strike gold on the Ford chassis. pnichols, do you tow with the V10? I see it's around ~300hp depending on the year but over 400# of torque regardless of the year. My concern is how much power is unlocked with bolt-ons on the V10? How durable are the transmissions when you start adding power and beating on them? It takes a lot to push something like that through the wind at altitude with a trailer at 70-75mph (interstate speed limit here is 75mph and trucks don't have a separate limit, I really don't think 60-65 would be a great idea and I doubt I have the patience to go that slow), I don't doubt one bit that near sea level without a trailer that the V10 is more than adequate. I know with the Vortec 454 that if you add a mild cam, headers, intake, and tune you'd easily be ~370hp and 500+ torque (at sea level), but the chassis I find them coming in so far just won't cut it. Of course that 8.1/Allison combo would boogie out with nothing more than a tune, but again we're talking $20k+ and possibly a difficult to find chassis. Maybe not, but I'm still ridiculously new to this. I really like the extras that the E-450 gives on the chassis and it's a bit much to buy a one ton and then upgrade everything on a GM chassis to a 450 equivalent, I don't think the dollars and cents would add up there. Time to hit CL and RVtrader again to research the more expensive rigs and further educate myself on what's out there.

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