GMT-900 Rumors

C/K Man · October 3, 2003

I have heard a few rumors about the next generation GMT-900 full size pickups. Here goes: The Chevrolet version will be known as the Cheyenne. Updated 3 valve versions of the LS-1 small blocks will have a lot more power, and there may be a 6.2L or larger version. A V-10 may replace the 8100, and have over 400 h.p.. Displacement on Demand will be used on some engines. A new 6 speed automatic will be available on 1/2 tons. A straight front axle may be used on 3500 4X4's. The 4500 Topkick/Kodiak may go back to using the light-duty pickup cab. SUV's will come out about 1 year before the pickups. I have no idea how reliable any of this is.

CMNTMXR81 · October 3, 2003

1) There is no secret as to the name, Cheyenne has been a show truck for awhile

2) The thre valve head or the dual in block cam engines have all been rumored ever since about 1998 when talk of the C6 came about. There have also been varying displacement rumors all between 6.0L and 7.0L. No one will know until the C6 hits the streets. GM is being VERY secretive on purpose much like no one knew of the LS1 until it was out.

3) GM WILL NOT DO A V10. This issue already arose before and has been written in several periodicals ever since they introduced the 8.1. The cost of R&D, re-tooling the Tonawanda engine facility to make both V-10's and BBC's isn't cost beneficial. They have a BBC that makes all the power they need in a much more efficient, cost efficient and easily interchangeable (parts wise) engine. Why invest all that money in a V10 to get the same power that simply upping the compression ratio on a 500 cube 8 cylinder will accomplish. Not to mention V-10's have a semi-odd firing system (in terms of crankshaft rotation) if memory serves me right, leading to a rougher running engine. It just doesn't make sense. The conventional BBC has proven durable, easily modifiable, efficient and parts are readily available. Something they'd have to start from scratch with on a V10.

4) GM Powertrain introduced a 6 speed automatic a few months ago. But it was for other customers, not for in house use.

Really nothing here is new news. Sorry.

C/K Man · October 3, 2003

Go to 'caranddriver.com', and look in the truck-SUV forum (Tough Guys) and check out the thread on 'Escalade V-10 Development'. I know a V-10 development of the LS-1 small block was considered as a replacement for the big block in the current GMT-800 trucks, but the idea was dropped. This new V-10 appears to be something different.

CMNTMXR81 · October 3, 2003

It still won't be done for the reasons I mentioned above.

GM invested a lot in re-developing the BBC. They wouldn't chuck it in a few years to have a more complicated engine that doesn't necessarily outpower what it replaces in a horsepower per cubic inch formula.

What GM Powertrain develops as "test mules" doesn't mean that's gonna make it to production. There's lots of other trick things Powertrain has got up their sleeves that you don't know about, doesn't mean it's going into production. And for what it's worth, Car and Driver is the last place I'd look for definitive future automotive plans.

C/K Man · October 3, 2003

Here is something from some time ago. Scroll down a bit and read the pasted article:

http://forums.pickuptruck.com/showflat.php...=5&o=93&fpart=1

I am certainly not going to say it is a go for sure, but it is starting to look like G.M. is once again considering a V-10. Two reasons that make it seem likely that one day they will do it are emissions and the ability to use 'Displacement on Demand'. If you compare same displacement V-8's to V-10's, the V-10's actually run a bit cleaner. A V-10 design allows for smaller bore sizes, and this reduces quench area and the area of the gap between the top of the first piston ring and the top of the piston itself. Unburned hydrocarbons love to hide in this little slot, and that's a problem that can only be solved by reducing the bore diameter, or moving the ring as high as you can on the piston (and if you were wondering about that cold start knock a lot of these new design engines have, this is a factor). Now, if you reduce bore diameter, you reduce displacement, and unless you go to a rediculous stroke, the only way you can build a big inch engine is add cylinders. Now, lets just say that a V-10 is on the way for 2007. That means the 8.1L was in production for 6 model years. That's not a bad run, and even though as you pointed out G.M. spent some money on tooling, the 8.1L is based quite a bit on the Vortec 7.4L, so it isn't quite an all new design. I would hate to see the 8.1L go, but if G.M. can build a 400+ h.p. V-10 that gets better mileage, I'm there!

CMNTMXR81 · October 4, 2003

It still isn't going to happen ANYTIME in the near future. 2006 is two years away (the 2004's are out) so if GM had this V10 in the works, it'd be out on the proving grounds being test now in order to be put on the market by 2006. So you'd have heard more than rumors.

There is a cost benefit system you are completely missing. You can go on about how more efficient a V10 is vs. a big bore V8, but the cost to bring this V10 to market is significantly greater at this point in time vs. the minimal emissions and fuel consumption reductions. D.O.D. can just as easily be implemented on the current BBC. As a matter of fact it was *supposed* to be on the 2002 8.1's. But they have continually delayed it to work out the bugs. So it itself isn't a reliable means of reducing emissions and fuel savings for either engine.

Then there is the aftermarket. And I'm not referring to big "Rat" motors in muscle cars. I'm talking about other applications that the BBC is used for. Those are Marine, industrial and power generation and whatever else. They are not going to readily adapt to a completely new form of Big Block power.

Sorry, I'll continue taking what I hear directly from the horses mouth myself.

C/K Man · October 4, 2003

Without a doubt, it won't happen at least until 2006, as a 2007 model year. As far as the aftermarket is concerned, I would imagine that the big block will still be around after if/when a V-10 is introduced. Remember, though they are no longer used in any new vehicles, Mark V and Mark VI big blocks and traditional Gen I small blocks are still manufactured in large numbers. A version of the old Nova 4 cylinder is also still in production, and that has not been used in a car since 1970! Anyway, it's all an educated guess right now. Also, the 6 speed auto I was talking about isn't out yet. There was an article about that on one of G.M.'s websites a while back. It is a replacement for the 4L60E, and is due sometime after 2005.

GMMediumDutyMQ · October 7, 2003

I'd be surprised that the C4500/5500 TopKick/Kodiaks would be switched to the light duty chassis again. Especially without reverting the Family 3 line (C6500, 7500, 8500) to the cab again also. They already share an assembly line, so why complicate things with the addition of a new cab? Granted, they were slow to be accepted, but look at what has happened since the full size cab has been introduced. Ford is now offering a cab back filler panel for E450 and E550 cutaways. Dodge is also introducing for '04 the (Mercedes) Sprinter cab/chassis, which is NOT a cutaway model. The fact that both of these competitors are creating a class 4 and 5 van-based cab and chassis models that AREN'T cutaways, but feature a solid back panel, show that perhaps GM had something here in this market, that the competition is nervous about.

BTW, I was able to ride and climb around one of those '04 Sprinter 3500 LWB DRW high roofs. Wow. While not the best feel in terms of trim, it wasn't that bad either. And they're HUGE. GM should get on the ball and introduce the Opel Movano (built by Renault) full-size vans over in this market. I've seen them @ Tech Center, and they would make a great GMC model by simply adding a "GMC" badge in the grille. These things rival the Sprinter through and through. Sadly, with the advent of the 610s, I doubt this will happen.

MQ

Mega Dogmeat · October 7, 2003

With the advent of displacement on demand, I can see why that GM might be seriously considering going with a V10 ...

Look at what the 4.3L V6 was, it was a "regular" SBC with 2 cylinders lopped off.

Why not just add 2 more?

The reason that I'm saying this, is that even though V10's would have an "irregular" firing pattern, it could very well be that given the displacement on demand technology they have been developing would require something like this for better balance when *NOT* running on all cylinders.

That kind of thing gets *VERY VERY VERY* complicated.....

I would be very interested in reading some more articles geared toward the "technicalities" of V10 balancing vs. V8, etc if any of you have any information on that?

That kind of thing really picks my curiosity, it's what I'm going to school for and stuff

Tucson_02Silverado · October 8, 2003

Cadillac was going to use a V12. It's supposedly been durability testing for the past year. The V10 was old news and cancelled as far back as LS1 development. Now if GM has started a new GEN program, yes it would be likely that a V10 would be looked at, but a V12 is more practical design wise as well as a Cadillac hertiage. The yet unannounced (or leaked) big sedan to replace the DeVille would need the V12 to distingish itself from it's smaller V8 brethern as well as from the MB S and BMW 7 that GM wants to dominate. The big Cadillac sedan is due for 2005, past the time the V12 would have complete durability testing. So there would probably be a special edition Escalade for 2004.5

Anyways if there is a new engine program, you'd have a minimum of two years for durability testing. 2004 out now, 2005's factory tooling being designed, so close to 2007 or 2008 for a new fully warranted engine generation.