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CSpec

Alpha platform in trouble: overweight, over cost

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A GMI original story, apparently:

Initially Alpha was going to be a four-cylinder only chassis for small premium cars, so naturally development focused on optimizing the Alpha platform for four-cylinder mills in a very light package. Well, Cadillac’s first condition was that Alpha be re-engineered to package a naturally aspirated V-6 engine – and that was non-negotiable. This about-face on engine selection would become the first of at least two engine requests that led to a re-engineering of the Alpha chassis to accommodate the new requirements. More changes (read: more mass and cost) were required for the addition of all-wheel drive.

What started out as a great handling, small RWD program, began it’s mission creep from being very focused to being all things to all people. And as it evolved, certain “hard-points” from previous development were locked in, even though the base program had transformed itself. For example, Alpha was designed with a very sophisticated multi-link front suspension with near perfect geometry for the car as it was developed at that point. That geometry was “locked in”. As the car grew and became heavier with more features and content, that original geometry was no longer optimal. Our sources tell us that GM is now attempting to mask this sub-optimal geometry with chassis tuning rather than doing the right thing and actually fix it.

According to sources familiar with the Alpha program both internally at GM and the supplier level, GM has made several other additions to the requirement list of Alpha beyond engines. Among the additions were: a new electronics system and aerodynamic shutters (similar to the Volt).

Each addition has caused another issue to engineer around, thus causing the Alpha program to exceed GM’s mass requirements for the car by nearly 500-pounds. It is unclear how heavy Alpha products will be, but every independent Alpha source GMI has communicated with has indicated that the final curb weight could push 4,000-pounds
unless GM puts the program on a mass reduction plan before launch.

Source

Alpha reportedly cost $1 billion. Reminds you of what got GM into bankruptcy in the first place doesn't it?

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Ok....sounds like Alpha will really be more of a hefty Zeta and Sigma replacement instead of a light compact car platform. Of course, anything under 4500lbs is 'light' for GM, who is used to building 5000-6000lb trucks and SUVs. :)

Worst case scenario, the bean counters will axe the program and the Caddy ATS will be a Delta FWD generic.

Edited by Cubical-aka-Moltar

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yes i thought alpha was going to be 4's , maybe a 6.. and then zeta and sigma were kinda merging for the 6's and 8's....?

isn't good news, if true...

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Alpha reportedly cost $1 billion. Reminds you of what got GM into bankruptcy in the first place doesn't it?

The cost is not out of proportion for a brand new platform development. That is why platform sharing is important to recuperate the costs.

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Alpha reportedly cost $1 billion. Reminds you of what got GM into bankruptcy in the first place doesn't it?

The cost is not out of proportion for a brand new platform development. That is why platform sharing is important to recuperate the costs.

The cost is out of proportion for a compromise platform that will not be able to compete.

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again, there is no way a 4-cylinder vehicle the size of the 3-series will weigh more than the 5-series unless they are building it from lead and lining the doors with gold.

Could the Alpha weigh up to that number? Sure... since they are planning on putting the CTS on it eventually too.

GMI is making a lot of hay over this... but some addition, subtraction, and basic deduction will lead you to a different conclusion than theirs.

The Epsilon platform can weigh as little as 3100lbs (Saab 9-3) or over 4200 lbs (Lacrosse AWD, Saab 9-5) and probably even more for the XTS. ZOMG! Sky is falling!

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again, there is no way a 4-cylinder vehicle the size of the 3-series will weigh more than the 5-series unless they are building it from lead and lining the doors with gold.

Could the Alpha weigh up to that number? Sure... since they are planning on putting the CTS on it eventually too.

GMI is making a lot of hay over this... but some addition, subtraction, and basic deduction will lead you to a different conclusion than theirs.

The Epsilon platform can weigh as little as 3100lbs (Saab 9-3) or over 4200 lbs (Lacrosse AWD, Saab 9-5) and probably even more for the XTS. ZOMG! Sky is falling!

Well said. That is the beauty of a platform being very flexible. No one knows what vehicles GM wants to build on this Alpha. I think someone at GMI is feeling a little insecure.

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The Epsilon platform can weigh as little as 3100lbs (Saab 9-3) or over 4200 lbs (Lacrosse AWD, Saab 9-5) and probably even more for the XTS. ZOMG! Sky is falling!

Different Epsilon. Either way, none of those cars are meant to compete with the 3-series. Driving dynamics are everything.

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Platforms HAVE to be flexible. I recall an article Borger sent me that talked about Alpha needing to be more flexible. This has been in the works for at least a year if not longer.

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The Epsilon platform can weigh as little as 3100lbs (Saab 9-3) or over 4200 lbs (Lacrosse AWD, Saab 9-5) and probably even more for the XTS. ZOMG! Sky is falling!

Different Epsilon. Either way, none of those cars are meant to compete with the 3-series. Driving dynamics are everything.

None of the bigger Alpha cars will be meant to compete with the 3-series either.

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Initially Alpha was going to be a four-cylinder only chassis for small premium cars, so naturally development focused on optimizing the Alpha platform for four-cylinder mills in a very light package. Well, Cadillac's first condition was that Alpha be re-engineered to package a naturally aspirated V-6 engine – and that was non-negotiable.

Why would this be a big deal, platform-wise? Typically, V6s, especially GM's narrower V6s easily fit into a space where a longer inline 4 has been intended. Assuming that Alpha's engine is longitudinal, not being able to fit a v6 would indicate an awfully narrow car.

Of course, reading between the lines... I don't see V8s mentioned here. If the next Camaro is Alpha based, has GM already nixed the V8?

What started out as a great handling, small RWD program, began it's mission creep from being very focused to being all things to all people. And as it evolved, certain "hard-points" from previous development were locked in, even though the base program had transformed itself. For example, Alpha was designed with a very sophisticated multi-link front suspension with near perfect geometry for the car as it was developed at that point. That geometry was "locked in". As the car grew and became heavier with more features and content, that original geometry was no longer optimal. Our sources tell us that GM is now attempting to mask this sub-optimal geometry with chassis tuning rather than doing the right thing and actually fix it.

Again, this is what I feared when Alpha was announced... a small platform that will be twisted and perverted to fit every application under the sun. Except in this case, I figured GM would have gotten Alpha to market as the ATS before GM started trying to use it for mopeds, boats and cubevans. GM has not learned that the one size fits all approach results in cars that are compromises before they can even get off paper.

According to sources familiar with the Alpha program both internally at GM and the supplier level, GM has made several other additions to the requirement list of Alpha beyond engines. Among the additions were: a new electronics system and aerodynamic shutters (similar to the Volt).

The electrical harness is considered part of the Alpha platform now? I imagine the electrical harness used on most cars changes constantly over the course of the years.

And what does the aerodynamic shutters have to do with the platforms?!? I simply don't see how this is specifically related to the platform. GM added these to the Cruze after the platform was designed.

I can only assume that the platforms have to be engineered specially for each color the cars are going to come in, as well. That would explain why GM is so limiting on the colors your car can be.

Each addition has caused another issue to engineer around, thus causing the Alpha program to exceed GM's mass requirements for the car by nearly 500-pounds. It is unclear how heavy Alpha products will be, but every independent Alpha source GMI has communicated with has indicated that the final curb weight could push 4,000-pounds unless GM puts the program on a mass reduction plan before launch.

Well, that don't surprise me. I'm sure one way or the other, Zeta will look good compared to Alpha because it suffered from less design-by-committee and more was-finished-5-years-ago. You would think by now GM would realize that a bird in the hand beats a bird in the bush.

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The more I read the article, the more I see the author's lack of understanding between a "car" and a "platform".

I think initially GM was going to have three independent RWD platforms - light Alpha, medium Sigma, and heavy Zeta. It seems like GM will end up having two, Alpha and the new Chi?? Future vehicles on Sigma and Zeta platforms may be now part of the Alpha, which may also be inter-related with Zeta "light" or Zeta 2.0. Since these cars (Camaro and CTS of the two) shift to Alpha, the author's argument that bigger engines were added later is true.

However the author fails to understand simplicity of modularity. If Alpha is modular, for a 4 cylinder engine the structural component of a bigger size may just have to be replaced with a smaller size and the weight essentially is decreased.

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The more I read the article, the more I see the author's lack of understanding between a "car" and a "platform".

I think initially GM was going to have three independent RWD platforms - light Alpha, medium Sigma, and heavy Zeta. It seems like GM will end up having two, Alpha and the new Chi?? Omega Future vehicles on Sigma and Zeta platforms may be now part of the Alpha, which may also be inter-related with Zeta "light" or Zeta 2.0. Since these cars (Camaro and CTS of the two) shift to Alpha, the author's argument that bigger engines were added later is true.

However the author fails to understand simplicity of modularity. If Alpha is modular, for a 4 cylinder engine the structural component of a bigger size may just have to be replaced with a smaller size and the weight essentially is decreased.

Fixed. Chi was the stillborn FWD sedan platform based off Lambda. DT7 and NG-Lucerne.

I think Sigma is dead after this round. It will be Alpha and next gen Zeta.

Alpha being as modular as Zeta could explain a large weight range between the extreme ends of the platform applications.

If they build an Alpha CTS-V that weighs 4,100lbs.... so what? That's what it weighs today.

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There are a few dubious assertions here...

(1) That the suspension geometry becomes sub-optimal because heavier V6 or even V8 engines are fitted is utter rubbish. Suspension geometry has everything to do with maintaining proper camber and toe during cornering and braking/acceleration. Given a particular geometry, the amount of these you experience has everything to do with the amount of actual body roll and squat. It has nothing to do with the weight of the vehicle. If the vehicle is say 10% heavier, you'll simply increase the spring rate and anti-roll bar size by the appropriate amount so the roll an squat at a given driving condition remains the same. Of course it is fixed by tuning, you don't change the control arm length or pick up points to fix these. You only change that if you are trying to lower or raise the ride height or change the centering force, etc. None of that has anything to do with weight!

(2) That somehow protecting the car for V6 or V8s will make the car heavier. Well, that may be the case when you actually install those engines, but the chassis weight probably won't change very much. The weight distribution may become less favorable with the heavier engines, but when these engines are not installed then the weight distrubtion ought to be as favorable as before.

(3) That a car can somehow benefit from being I4 only in terms of packaging and handling is also for the most parts nonsense. First of all an I4 is for the most parts as long as a V8. A V6 is shorter! Width wise, most cars are governed by the width of the desired passenger cell, not be the engine width. Let me put it this way... the widest suspension tower boxes in the industry are the 1990s Honda ones because of the double wishbone fronts. Even then, if you look at an S2000, there is plenty of room on each side of the F20C Inline-4. The additional width introduced by a 60 deg DOHC V6 or a 90 deg Pushrod V8 is about the same as the room needed for a typical Inline-4's intake runner andd plenum assembly!

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What they fail to say is that the platform will be able to support models from 3400-4000 pounds.

I am sure a CTSv V8 or TT V6 with AWD in the longest and widest wheel base may be 4000 pounds. That does not mean the Camaro or ATS and other models will be that heavy.

Also when you share a platform there will be comprimises that will add to weight or the ability to do some things that a single model platform can do. When you gain flexibility you have to comprimise in some areas.

I would not hit the panic button yet on this deal. While when it comes out I am sure many will say it could or should be lighter but they would still say that at 3100 pounds too.

Lets just see what we really get.

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GM does tend to cut costs or take short cuts when they can. So if they go that route with Alpha and compromise the platform to make it all things to all people it will be sad. What worries me, is they have to make it cheap enough for Chevy, build a small Cadillac, a mid-size Cadillac, possibly another car. The 3-series platform is purpose built, they don't have to compromise it. It would be unfortunate if the Alpha platform is not capble and the ATS and next-gen CTS are just mediocre. But only time will tell.

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GM does tend to cut costs or take short cuts when they can. So if they go that route with Alpha and compromise the platform to make it all things to all people it will be sad. What worries me, is they have to make it cheap enough for Chevy, build a small Cadillac, a mid-size Cadillac, possibly another car. The 3-series platform is purpose built, they don't have to compromise it. It would be unfortunate if the Alpha platform is not capble and the ATS and next-gen CTS are just mediocre. But only time will tell.

Let's put it this way... the 3-series is not that light. The E90 is not the E36, not by a long shot. The E90 3-series is about 3425 lbs for a 328, going up to about 3850 lbs for a well equipped 335xi. If the ATS comes in at 3800 lbs for a V8 or Bi-turbo V6 powered ATS-V, that's not ideal but its not the end of the world. I don't think it'll be that bad though... the Zeta is "only" 3900 lbs with the V8 and just by virtue of the shorter wheelbase alone -- even if none of the weight saving efforts paid off -- the Alpha would be no more than about 3800 lbs with a V8. That's not great, but that's not horrible either. Of course we all hope for a 3600 lbs ATS-V with Small block power (maybe 3650~3700 if they went with a twin turbo V6). This will peg a 3500 lbs entry level car with a V6 or Turbo I4 (the V6 and I4 actually weigh about the same). That's fully competitive.

Edited by dwightlooi

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The progress of the Alpha program sounds a lot like what GM should guard against: too many (bad) ideas spoiling the whole thing. I was watching the latest Mazda commercial, and it implied that they know how to craft a small nimble vehicle while "behemoth automakers" (read GM and Ford) simply cannot. Unfortunately, Alpha was not as well-protected as the Corvette program, hence all the screw-ups and conflicting demands. Cadillac does not really need a 4cyl car unless it is worth driving (avoiding the curse of Cimarron). Alpha should actually be a Chevy (if not a Buick) and let Caddy have a somewhat larger car take care of the ATS.

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There are a few dubious assertions here...

(1) That the suspension geometry becomes sub-optimal because heavier V6 or even V8 engines are fitted is utter rubbish. Suspension geometry has everything to do with maintaining proper camber and toe during cornering and braking/acceleration. Given a particular geometry, the amount of these you experience has everything to do with the amount of actual body roll and squat. It has nothing to do with the weight of the vehicle. If the vehicle is say 10% heavier, you'll simply increase the spring rate and anti-roll bar size by the appropriate amount so the roll an squat at a given driving condition remains the same. Of course it is fixed by tuning, you don't change the control arm length or pick up points to fix these. You only change that if you are trying to lower or raise the ride height or change the centering force, etc. None of that has anything to do with weight!

What if control arms, etc, were repositioned in order to gain clearance for a DOHC V6 or smallblock V8?

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There are a few dubious assertions here...

(2) That somehow protecting the car for V6 or V8s will make the car heavier. Well, that may be the case when you actually install those engines, but the chassis weight probably won't change very much. The weight distribution may become less favorable with the heavier engines, but when these engines are not installed then the weight distrubtion ought to be as favorable as before.

Disagree there slightly. The structural components used to support the engine will vary in size depending on the size of the engine. Since the size is directly proportional to the mass of the vehicle, increasing engine size means increasing structural components' mass to carry the load while maintaining the same structural stiffness. Most of these components are high strength steel alloys, which add a lot of weight.

So for a hypothetical example, if a 3" diameter torsion bar is selected for a 8 cylinder engine member support, for a 4 cylinder engine, the same job can be done by a 2.1" diameter member, assuming the the 4-cylinder weighs exactly half of the 8-cylinder engine. That is almost 30% weight saving.

There are a few dubious assertions here...

(1) That the suspension geometry becomes sub-optimal because heavier V6 or even V8 engines are fitted is utter rubbish. Suspension geometry has everything to do with maintaining proper camber and toe during cornering and braking/acceleration. Given a particular geometry, the amount of these you experience has everything to do with the amount of actual body roll and squat. It has nothing to do with the weight of the vehicle. If the vehicle is say 10% heavier, you'll simply increase the spring rate and anti-roll bar size by the appropriate amount so the roll an squat at a given driving condition remains the same. Of course it is fixed by tuning, you don't change the control arm length or pick up points to fix these. You only change that if you are trying to lower or raise the ride height or change the centering force, etc. None of that has anything to do with weight!

What if control arms, etc, were repositioned in order to gain clearance for a DOHC V6 or smallblock V8?

Yes, they will be needed to modified to control the additional weight transfer more than gaining clearance.

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There are a few dubious assertions here...

(2) That somehow protecting the car for V6 or V8s will make the car heavier. Well, that may be the case when you actually install those engines, but the chassis weight probably won't change very much. The weight distribution may become less favorable with the heavier engines, but when these engines are not installed then the weight distrubtion ought to be as favorable as before.

Disagree there slightly. The structural components used to support the engine will vary in size depending on the size of the engine. Since the size is directly proportional to the mass of the vehicle, increasing engine size means increasing structural components' mass to carry the load while maintaining the same structural stiffness. Most of these components are high strength steel alloys, which add a lot of weight.

So for a hypothetical example, if a 3" diameter torsion bar is selected for a 8 cylinder engine member support, for a 4 cylinder engine, the same job can be done by a 2.1" diameter member, assuming the the 4-cylinder weighs exactly half of the 8-cylinder engine. That is almost 30% weight saving.

There are a few dubious assertions here...

(1) That the suspension geometry becomes sub-optimal because heavier V6 or even V8 engines are fitted is utter rubbish. Suspension geometry has everything to do with maintaining proper camber and toe during cornering and braking/acceleration. Given a particular geometry, the amount of these you experience has everything to do with the amount of actual body roll and squat. It has nothing to do with the weight of the vehicle. If the vehicle is say 10% heavier, you'll simply increase the spring rate and anti-roll bar size by the appropriate amount so the roll an squat at a given driving condition remains the same. Of course it is fixed by tuning, you don't change the control arm length or pick up points to fix these. You only change that if you are trying to lower or raise the ride height or change the centering force, etc. None of that has anything to do with weight!

What if control arms, etc, were repositioned in order to gain clearance for a DOHC V6 or smallblock V8?

Yes, they will be needed to modified to control the additional weight transfer more than gaining clearance.

I know weight tranfer was a concern when Alpha was modified to accept a HFV6.

Edited by Chazman

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I know weight tranfer was a concern when Alpha was modified to accept a HFV6.

Balance I would think would be an issue....

Certainly BMW and M-B have figured it out w/ their compact cars..after all, the 3 series is available w/ 4s, straight 6s, and V8s...and the Merc C-class is available w/ 4s, V6s, and V8s...and both are widely regarded as the best in the business for compact luxury/sports sedans/coupes.

I know GM has no history of building such cars, but Alpha is their opportuntity to prove they can build big league-competitive compact luxury sports sedans and coupes..I hope they can pull it off..

Edited by Cubical-aka-Moltar

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The problem, as I see it, with this article is the assumption that all vehicles built on the Alpha have to compete with the 3-series.

That isn't true.

The Camaro would and should have a very different driving personality than the ATS. If Buick were to get an Alpha for.. oh I dunno.. a Riviera, that would have a much softer performance threshold than the first two I mentioned and yes would probably be 3700 lbs. And if Alpha can be scaled up to be CTS sized... then yes, I expect it to weigh to 4,000 lbs in fully loaded AWD format.

Only one of the vehicles known to be on this platform has to compete with the 3-series and that is the ATS. It'll be in showrooms in about 12-14 months to make its case.... lets try to not bash it too much before we even see it.

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The problem, as I see it, with this article is the assumption that all vehicles built on the Alpha have to compete with the 3-series.

That isn't true.

The Camaro would and should have a very different driving personality than the ATS. If Buick were to get an Alpha for.. oh I dunno.. a Riviera, that would have a much softer performance threshold than the first two I mentioned and yes would probably be 3700 lbs. And if Alpha can be scaled up to be CTS sized... then yes, I expect it to weigh to 4,000 lbs in fully loaded AWD format.

Only one of the vehicles known to be on this platform has to compete with the 3-series and that is the ATS. It'll be in showrooms in about 12-14 months to make its case.... lets try to not bash it too much before we even see it.

I would think making a model competitive w/ the 3-series, etc would be the main focus..anything else is secondary. Cadillac absolutely has to have a hit in this niche.

It will be interesting to see if they can scale it up to midsize to accomodate 4000lb CTSes and Camaros. It would have to be able to scale in width, length, track, etc. An ambitious goal.

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A C-class is 3,527-3,615 lbs for the V6 models. If the 4-cylinder model goes on sale here (which I think it is) I assume that will be more in the 3,480 lbs range. A 328i is 3,428 lbs. I think the ATS needs to be in that 3500-3600 lb range, and should have a turbo 4-cylinder and DOHC V6.

The Camaro should be in that weight range too, a Mustang is around 3,500 lbs and the Genesis coupe is even less. CTS can be 4,000 lbs, all those mid-sizer are now, but then again, with CAFE going higher and higher, automakers will be forced to cut weight.

Edited by smk4565
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