CD4 Chassis School

[JohnZiraldo]

How did anyone come to the conclusion CD4 had anything to do with the new Mustang?

Let me take a stab at that.

We were sharing a lot of anxiety about whether S550 was smaller, lighter, stronger than the new GM Alpha platform, or just a tweaked S197. To say that we were anxious about that is probably an understatement.

I for one pleaded my ignorance about modern platforms to the forum because I did not know why a 'clean sheet' design had to be necessarily superior to an 'evolved' platform. The Pill jumped in with his CD4 Chassis School to help relieve us of our ignorance by bringing us a lot of presentation data about some of Ford's latest and greatest platform technologies.

Our speculation and wishful thinking made us want to believe that S550 might be an evolution of Ford's best design and metals technologies, and that it could be a RWD version of Ford's latest platform, ie. CD4+.

We have followed a similar path in helping ourselves to believe that the IRS for S550 will be the latest, greatest, lightest, strongest IRS ever built.

Cooler and newer heads prevailed and convinced us that there is no CD4 under the S550. We are now back to square one.

The Pill has indicated that he for one is going to wait for more facts from Ford in order to start up a new "S550 Chassis School" and an "S550 Suspension & Braking School".

So, CD4 Mustang talk is dead! Long live CD4 in FWD cars!

Now let's talk about what we KNOW about the newest, lightest, strongest, fastest chassis, suspension, and braking systems ever conceived. S550 :first:

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[All-Or-Nothing]

S550 is just an evolved/modified S197 chassis.

 

[crazyfastfreddy]

i know some peeple will think thats a bad thing but i dont. the s197 has been able to do so much it would only take some modification to take it to the next level. swap at some parts for some aluminum and better suspension (which we know is coming) and there you go.

since when do we need a cleansheet redesign to be happy? mustang's never had one before far as i know.

 

[thePill]

I wouldn't call the S550 an evolved S197. It could very well use components from the S197 like, the transmission/drive shaft tunnel... In my opinion, the S550 would have about as much in common with the S197 as man and ape (Fox and SN95). At the same time, anyone that knows anything about chassis will tell you, the front strut towers on a FWD are in a different location than a RWD. That portion of the CD4 cannot carryover.

Another thing to consider, the S550 is using Ford's "Silhouette Innovation" while the S197 doesn't. Major changes to the safety structure and engine cradle are needed. The S brace is a critical design/engineering element in the S550 and is completely absent from the S197. The Y brace will eliminate the torque box and is another critical element absent from the S197. The HUGE sled runners as well... Therefore, in my opinion, it wouldn't be S19Anything...

However, since the front strut towers need to be repositioned forward, the rear needs to accommodate ILIRS and RWD and is a 2 door w/ a transmission/shaft tunnel, I wouldn't call this a CD4 either.

Although, it may use an S197 tunnel and CD4 floor and trunk pans...

 

[Overboost]

S550 is just an evolved/modified S197 chassis.

Nice to see you continue to troll the boards.

 

[JohnZiraldo]

S550 is just an evolved/modified S197 chassis.

i know some peeple will think thats a bad thing but i dont. the s197 has been able to do so much it would only take some modification to take it to the next level.

I will second that notion.

 

[JohnZiraldo]

...
Another thing to consider, the S550 is using Ford's "Silhouette Innovation" while the S197 doesn't. Major changes to the safety structure and engine cradle are needed. The S brace is a critical design/engineering element in the S550 and is completely absent from the S197. The Y brace will eliminate the torque box and is another critical element absent from the S197. The HUGE sled runners as well... Therefore, in my opinion, it wouldn't be S19Anything...

OK Prof. Pill, now you have lost me. What is Ford's "Silhouette Innovation", and how do we know that S550 uses the S and Y braces and Huge sled runners?

Is it time to start the S550 Chassis School and move this discussion out of CD4 School?

 

[thePill]

OK Prof. Pill, now you have lost me. What is Ford's "Silhouette Innovation", and how do we know that S550 uses the S and Y braces and Huge sled runners?

Is it time to start the S550 Chassis School and move this discussion out of CD4 School?

SI is Ford's marketing term for the basic "Bullet" or "egg shaped" safety structure that most Ford vehicles have switched to.

The S Brace joins the Engine Cradle, A pillar, Firewall and Rocker into almost a modular structure (semi-spaceframe-ish). The Y Brace (joining the two S braces together) elminates the torque box and allows Ford to invest that saved weight into MAJOR load bearing sled runners.

The S550 can't be a CD4 with the current front strut tower location. It also needs to have a transmission/shaft tunnel engineered in and, it will have a unique rocker, roof and pillar design as well as cowl/firewall. I wouldn't consider that a CD4 chassis even if Ford told me that's what it is.

The S550 can't be an evolved S197 either, the sheer amount of restructuring the S197 needs to meet the SI language (mentioned above) would be very drastic. The only thing that could be used in the transmission/shaft tunnel. The rear could be similar (underneath) but the B and C pillars, roof/window, trunk and quarter panels are all new. The front suspension is way different in the S550 vs. the S197. If something is new, it isn't evolved. Again, I wouldn't consider this an S197 is Ford told me that's what it is...

You can't re-engineer the S197 with the S and Y braces without totally re-doing the entire structure. It would cease to function properly when loads increase and, it wouldn't distribute energy properly during a collision.

In my opinion, I don't think it is either an evolved S197 nor an evolved CD4. Although, the floor pans, trunk floor and transmission tunnel could be used from the S197. The CD4's floors and trunk floor could be used as well. The S197 and CD4's engine cradle will not carry over due to strut tower height and angle (S197) and the FWD strut tower location (CD4). Silhouette Innovation counts the S197 out, RWD really alienates the relationship between CD4 and S550 too... So... It's hard for me to consider the S550 an evolved S197 OR a CD4.

It has to be something new with few things borrowed. Those areas I mentioned above.

 

[All-Or-Nothing]

Nice to see you continue to troll the boards.

Meh....like you calling me a Troll makes what I said any less true.

 

[motoroid65]

Doesn't matter. Enough changes have been made that it is called all-new. We'll do a post-mortem after the car is out but you will never hear Ford call it an evolved S197 in public. And I can guarantee you it won't be CD4.#. That makes no sense.

 

[Overboost]

Something worth mentioning, the S197 isn't it's own platform, but rather the D2C platform. So, it's not an evolved D2C and may share loose design with the CD4 family.

 

[thePill]

If you really want to get technical, the new "CD" global designation is a combination of the previous "C" and "D" platforms (mid and full size). So, if the new S550 does turn out to be an evolved D2C ("D" Full size, 2 door Coupe "2C") then is will still fall under the CD family.

If slightly downsized (107 is a very small full size wheelbase anyway), then it wouldn't surprise me to find out Ford has made a sorta C2C to replace the D2C which still falls under the CD family however, it will be considered a regional platform and not a global... still being offered globally though.

Either way, it will have very little physical relation to the D2C or the CD4.

 

[Overboost]

If you really want to get technical, the new "CD" global designation is a combination of the previous "C" and "D" platforms (mid and full size). So, if the new S550 does turn out to be an evolved D2C ("D" Full size, 2 door Coupe "2C") then is will still fall under the CD family.

If slightly downsized (107 is a very small full size wheelbase anyway), then it wouldn't surprise me to find out Ford has made a sorta C2C to replace the D2C which still falls under the CD family however, it will be considered a regional platform and not a global... still being offered globally though.

Either way, it will have very little physical relation to the D2C or the CD4.

What you just said there is the same logic I applied to it. D platform is being absorbed by CD4, so why wouldn't D2C? Again, it's not cookie cutter, but more of a family with some common components or design elements.

 

[thePill]

What you just said there is the same logic I applied to it. D platform is being absorbed by CD4, so why wouldn't D2C? Again, it's not cookie cutter, but more of a family with some common components or design elements.

Only because I wouldn't consider any platform with only a 107 inch wheelbase "full size". Full size platforms start at 110 inches...

Call it what it really is, before it couldn't be done because it was based on the "D" platform. Since "CD" has absorbed both "C" and "D", why not call it a C2C. C Class Mid-size, 2 Door, Coupe...

It would be new, a class smaller (even though very little has changed).

It may be absorbed into the CD family but, it won't carry over much. The the current D2C will have just as much in common with a Fusion CD4 as the S550 will. There are just too many changes needed for me to consider it a CD4.

The D2C will also need significant changes, some which were visually confirmed in the engine bay spy pics, for this to be an evolved S197 as well. The CD4 cannot support a RWD V8, fore/aft mounted transmission or a deep drive shaft knuckle to compensate for the lower ride height.

A RWD engine cradle is needed that supports forward mounted strut towers. The S/Y braces and the sleds are changed with the cradle. The rear could possibly be a version of the CD4 but, I'm only talking from the axle back... In my educated opinion, floor pans and truck floors are not the meat of the platform. You don't design a chassis on existing floor pans...

The D2C would need an extreme make over... Everything but perhaps the knuckle and pans. The rear would need a make over because it is way more difficult to retro fit ILIRS to a SLA chassis then vice versa.

If it's a CD4, the axle back and floor pans will be the only S550/Fusion relation as far as platform. The ILIRS is being used so, that is supported.

If it's a D2C/evolved S197, the transmission knuckle/shaft tunnel and floor pans will be the only S550/S197 relation in the platform.

Either way, not even Ford could convince me either one is true. The S550 is probably so heavily evolved from the CD4, that it is unrecognizable.

You will have just as much luck convincing me the Fox-4 was an "evolution" of the Fox Body. Educated people would tell you other wise...

 

[mister.peabodyjunior]

Only because I wouldn't consider any platform with only a 107 inch wheelbase "full size". Full size platforms start at 110 inches...

Call it what it really is, before it couldn't be done because it was based on the "D" platform. Since "CD" has absorbed both "C" and "D", why not call it a C2C. C Class Mid-size, 2 Door, Coupe...

It would be new, a class smaller (even though very little has changed).

It may be absorbed into the CD family but, it won't carry over much. The the current D2C will have just as much in common with a Fusion CD4 as the S550 will. There are just too many changes needed for me to consider it a CD4.

The D2C will also need significant changes, some which were visually confirmed in the engine bay spy pics, for this to be an evolved S197 as well. The CD4 cannot support a RWD V8, fore/aft mounted transmission or a deep drive shaft knuckle to compensate for the lower ride height.

A RWD engine cradle is needed that supports forward mounted strut towers. The S/Y braces and the sleds are changed with the cradle. The rear could possibly be a version of the CD4 but, I'm only talking from the axle back... In my educated opinion, floor pans and truck floors are not the meat of the platform. You don't design a chassis on existing floor pans...

The D2C would need an extreme make over... Everything but perhaps the knuckle and pans. The rear would need a make over because it is way more difficult to retro fit ILIRS to a SLA chassis then vice versa.

If it's a CD4, the axle back and floor pans will be the only S550/Fusion relation as far as platform. The ILIRS is being used so, that is supported.

If it's a D2C/evolved S197, the transmission knuckle/shaft tunnel and floor pans will be the only S550/S197 relation in the platform.

Either way, not even Ford could convince me either one is true. The S550 is probably so heavily evolved from the CD4, that it is unrecognizable.

You will have just as much luck convincing me the Fox-4 was an "evolution" of the Fox Body. Educated people would tell you other wise...

You pretty much explained the relationship between the two. Similar ILIRIS. The rest is unique. Key point here, CD4 doesn't support a convertible, S550 does, which is accounted for in the rear floor/chassis. CD4 has no such provisions nor is there any plan.

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