Front Splitter for Gen II?

[ZYellow01RT]

Great stuff. I'm sure my mom would be impressed. But after 30 years in engineering, I'm able to sift through what matters and what doesn't. Your points don't matter in this discussion in regards to the stresses on the fascia and it's members and the materials used to build them.

Um, how thick is, and what material is the Autoform stick-on splitter? Sure you won't post it. Just like you won't post how it attaches. I can understaned how it's embarrassing compared to these robust and fully functional units that everyone likes. Whoops, sorry. Most everyone likes.

Clean up your inbox so that I can send you some technical info for you (and your mom) to read. And learn from.

 

[shooter_t1]

That street autoform splitter on the yellow car is gotta be the ugliest splitter made. Like a Viper with downs syndrome or something.

 

[dave6666]

That street autoform splitter on the yellow car is gotta be the ugliest splitter made. Like a Viper with downs syndrome or something.

​

 

[ZYellow01RT]

I don't care what anyone says, nothing adds value to a car like home made cosmetic mods.

You must be registered for see images attach

 

[2000_Black_RT10]

All polymers flex. The question is at what force.

Is your 3/8* thick material actually "CFRP" (carbon fiber reinforced polymer), or is it actually "FRP" (standard pultruded fiber reinforced plastic)? Big difference in shear moduli (i.e., rigidity).

For reference, the CFRP measures ~ 3750 GPa , while the FRP is magnitudes lower (~ 1.3 - 5.0 GPa). Still damn stiff, but the difference between the two materials is substantial.

For a bit of background in interested, perhaps you know all of this, typically for front splitters that are manufactured from carbon fibre are not solid. What may look like a thick carbon fiber splitter is typically comprised of a couple layers on either side of core material, core material being a like Nomex honeycomb aluminum, paper or foam, like Rohacell. There is a structural / stiffness advantage of having the box section with a bit of core with less carbon fibre material. The actual thickness of carbon fibre applied would be around 5 mm or so, that's 2.5 mm on either side +/- 1 mm. Stiffness of a composite part is typically defined by the number of layers and type of weave. Then there's the finish, some perhaps like the clearcoated exposed carbon fibre, like a 2x2 or 4x4 weave, different GSMs, and ideally a unidirectional weave is best for a smooth painted finish, but must be oriented in the best direction to accommodate stress. Race cars, like the stuff I helped to design such as the Daytona Prototypes, weight is a significant factor. Usually also design a pocket on the underside of the splitter for replaceable sacrificial nylon blocks, that take the hit or scrub the track, etc., rather than damaging the splitter itself. There's also some aftermarket companies that wet lay carbon fibre, there's more resin / epoxy mass, yet you don't get the stiffness compared to an autoclaved part (compressed in a vacuum bag in addition to pressure) because of the better resulting material consolidation with pre-preg. Dive planes only get you another 10 or 15 lbs of downforce depending on the design, sure this is significant for race cars competing, but for a street car... they can look cool.

I think Dave's splitter is beyond being adequate for stiffness, sure a few pounds heavier, but is that really a concern on a street car? Ideally it's a suitable material if it gets banged up on the street, as I wouldn't want to be replacing a carbon fibre splitter, the cost can be very high for an autoclaved part, which would be around $1000 at minimum to manufacture (and this all depends on the additional piece costs with a volume to make up for the upfront tooling costs including the pattern, carbon fibre mold, etc., which would be around $25k for a carbon fiber splitter that meets race car / FIA / OEM specs). Sure there's cheaper wet laid parts on the market, but again, they're not as good.

I think when all is considered, weighing all of the advantages, disadvantage, functionality and feasibility, it's very hard to beat what Dave fabricated for his street car. It looks good too. I can't knock it that's for sure. Heck that last car I helped design comprised of a full carbon fibre chassis sells for $2M ea., but there's something of value to be noted and respected when somebody takes the time to fabricate it themselves rather than buying a mail order part. There's some of us in the industry that I work who fabricate stuff in our garages, and it's one of the qualities of a designer or engineer that is greatly valued. My last boss was a VP of engineering at Shelby, he always encouraged the engineers to go work in the shop, it's an asset regardless of the costs or types of material being used, and what is valued more is coming up with a design that is the best feasible solution with a given budget.

I don't know what Dave's budget was, but I bet if you stack up his receipts, heck I surely wouldn't challenge him on fabricating a better solution. Shame on anyone who says it's "homemade", some need to be a bit more impeccable with their words.

Cheers,
Mike

 

[dave6666]

Clean up your inbox so that I can send you some technical info for you (and your mom) to read. And learn from.

Gee. I'll make a special condition for you.

You see, back to engineering, and it's quite obvious you're getting ruffled up here with your last post referencing my mother (which will even get you banned at the Alley), that you are only throwing textbook stuff out that really doesn't matter to this application.

That splitter maybe generates a few hundred pounds of downforce. Spread over the load area, the stresses are miniscule. If it was made of notebook paper it would matter, but it's not. Carbon fiber or GRP, no difference in their structural property versus the load matters. It's like 100,000/1 versus 1,000,000/1. A minor design consideration that anyone trying to make a valid point would ignore for this part. This is not the space shuttle.

Secondly, the flex of the blade plane is further eliminated by the continuous attachment along the leading edge of the fascia, and in many cases, the support cables (made of metallic materials) offering additional stress relief as it operates as a cantilever. Add that to the physical material property analogy I made above, and the material is even less relevant.

In summary, you appear to know sqaut about cars or practical engineering, and are trying to impress everyone with texbook stuff that quite honestly someone is probably faxing to you to write here.

 

[ZYellow01RT]

Gee. I'll make a special condition for you.

In summary, you appear to know sqaut about cars or practical engineering, and are trying to impress everyone with texbook stuff that quite honestly someone is probably faxing to you to write here.

Corrections made. Please spell correctly when you insult someone's intelligence.

As for the rest of your comments...some valid, others not. And I'll leave you with the belief that you are smarter than everyone else.

 

[aloushi]

Andrew and Dave, let's settle this once and for all...both of you offer your splitters for sale and the rest of us will bid on them, the one with the higher bid wins and the other ***** @ss

I bid $100 (shipped) for Dave's...

 

[ZYellow01RT]

Andrew and Dave, let's settle this once and for all...both of you offer your splitters for sale and the rest of us will bid on them, the one with the higher bid wins and the other ***** @ss

I bid $100 (shipped) for Dave's...

LOL...that's fair. I bid $105 for Dave's (shipping extra).

 

[2000_Black_RT10]

Secondly, the flex of the blade plane is further eliminated by the continuous attachment along the leading edge of the fascia, and in many cases, the support cables (made of metallic materials) offering additional stress relief as it operates as a cantilever. Add that to the physical material property analogy I made above, and the material is even less relevant.

Yes Dave, as well as being rigid providing some adjustment.

Check out the splitter at the beginning on this race GT3 Ford Mustang (challenging car to get downforce and reduce lift, note the blocked off grille) which (the complete cars) were designed and built at my last place / facility by coworkers (and in Canada eh') in the video for Marc VDS Racing (Marc the customer from Belgium who's family owns Stella Artois and Budweiser for a beer related topic you may enjoy..), very nasty cars btw, big budget, carbon fibre body panels, rear transaxle, etc.. The racing industry prefers function vs. appearance, as it is a big splitter, but a coworker Mark H. was / is one of the top aero guys in the racing industry, involved with F1, etc.

http://www.youtube.com/watch?v=kkQDF3PCzv0

Cheers,
Mike

PS.. more info if interested (hey, even my wife heard enough of my work stuff eh').. Marc VDS Racing site link below, and a following pic of Marc with the Mustang in race livery from Belgium below.

http://www.marcvds.com/gt3/news.cfm...3-launched-in-belgium&language=english&page=1

You must be registered for see images

For another leading front end example, I also designed the carbon fibre patterns and molds for this customer's Grand-Am car, quite a different design.. (company is / was pretty tight with Lola, some of the composite guys came from the UK / Lola).

http://www.krohnracing.net/content/about-car_specs

You must be registered for see images

..and one last old splitter pic from the shop, since they did all the GTS-R carbon fibre mold / design stuff for Oreca / Chrysler back then.

You must be registered for see images

 

[DrumrBoy]

Mine is plate aluminum....wouldn't recommend it because it weighs too much. It does have one advantage though, with successive rubs on the pavement during suspension compression (or going in and out of pits on hills) it has now become a fairly sharp blade capable of cutting grass efficiently or removing bunny heads from the bunnies. We tape towels all over it when its on the lift to prevent head-bumps from becoming decapitations.

 

[mjangstadt]

What did you attach the support rods to?