NASA Spec3 Build By Kaplhenke Racing

[blkaplan]

We have been building this car over the last month, it is the 2nd SPEC3 in existence as Cabetto (head of nasa midatlantic) finalizes the rule set for public release. We hope this car will drum up some excitement for the new e36 based racing series.

Its my first bmw project, what do you guys think?

you can find more pics @ my site but i will hotlink a couple good ones

http://www.kaplhenke.com/index.php?o...d=58&Itemid=48



Polished tubing makes for clean weld surfaces and removes all scratches, mill scale, and irregularities.


































Vinyl package + 300 hp





@ VIR

[getfast]

Beautiful!

Jon

[tfro]

Interesting x in the rear.

Great fit on the cage. It's too bad you have to paint the cage, maybe just a clear coat

[Dino Antonov]

Great fit on the cage. It's too bad you have to paint the cage, maybe just a clear coat

Took the words right out of my mouth. I mean that thing is GOOOD (anchorman)

[jmitro]

very interesting X. seems much more time consuming to make, with less rearward vision than the standard X.

otherwise nice build

[blkaplan]

very interesting X. seems much more time consuming to make, with less rearward vision than the standard X.

otherwise nice build

It was very time consuming but the way the members joint gives it great torsional stiffness, much more then the standard X. It also allows input forces to be distributed at a much wider range of input angles without loading the tubing in bending.

The rearward vision is actually excellent as we offset the junction point on the low side, from the drivers seat the top gusset plate is 2" below the 3rd brake light so there is 0 obstruction from the gusseting. The fact that it is offset actually makes it have better visibility then the normal X as well.

[blkaplan]

Interesting x in the rear.

Great fit on the cage. It's too bad you have to paint the cage, maybe just a clear coat

We are going to clear it

initially it was going to be painted orange but the polishing turned out so amazing that it would be a shame to cover it up.

[Steve J.]

It was very time consuming but the way the members joint gives it great torsional stiffness, much more then the standard X. It also allows input forces to be distributed at a much wider range of input angles without loading the tubing in bending.

Can you further explain this theory. Your load paths are redirected from the shortest path possible. The bends are inherently weaker than a straight peice of tubing. I'm interested to see why you think (or maybe have some FEA) on how its much more rigid than a straight X with 4 gussets.

Also, how thick are the sheet gussets, 065?

I assume the start inserts are for show and you did not want the extra rigidity from flaring the holes?

Looks great, but not sure if its more functional than other techniques.

[RacerX]

Can you further explain this theory. Your load paths are redirected from the shortest path possible. The bends are inherently weaker than a straight peice of tubing. I'm interested to see why you think (or maybe have some FEA) on how its much more rigid than a straight X with 4 gussets.

Also, how thick are the sheet gussets, 065?

I assume the start inserts are for show and you did not want the extra rigidity from flaring the holes?

Looks great, but not sure if its more functional than other techniques.

I would assume, in part, that he is referring to a standard X without gusseting.

Personally, I like the seemingly artistic integration into the functional design...color me impressed.

[RacerX]

BTW...what size tire and what suspension? OTE's wouldn't be a problem with some dirt stockers. Dayum!

[Steve J.]

I would assume, in part, that he is referring to a standard X without gusseting.

Personally, I like the seemingly artistic integration into the functional design...color me impressed.

I like the artistic aspect as well, but its a racecar, not a show car Comparing an X w/o gussets does not make much sense though.

Now if it had some FEA to back it up, and it turns out to in fact be more structural, that'd be awesome. Kind of like the new AP calipers. Works of art (but i've heard they have had issues, although the nascars are winning with them now).

[blkaplan]

Can you further explain this theory. Your load paths are redirected from the shortest path possible. The bends are inherently weaker than a straight peice of tubing. I'm interested to see why you think (or maybe have some FEA) on how its much more rigid than a straight X with 4 gussets.

Also, how thick are the sheet gussets, 065?

I assume the start inserts are for show and you did not want the extra rigidity from flaring the holes?

Looks great, but not sure if its more functional than other techniques.

I did some initial FEA theory a ways back I don't have any of the results saved but i can try and recreate it and post my results.

You are dead on with the thickness of the gussets. .065 Cold rolled steel.

You are wrong about the inserts, we laser cut all the gussets for this project, if we just wanted the inserts for show i would have laser cut them and not spent hours welding them onto the plates. The gussets are flared and then have the inserts seamed on top them, The inserts are mainly a branding extra that we added but they do add a 7% increase in torsional rigidity to the gusset plates.




You can see the gussets here with the flared holes before we welded to them

[M3 Muscle]

It was very time consuming but the way the members joint gives it great torsional stiffness, much more then the standard X. It also allows input forces to be distributed at a much wider range of input angles without loading the tubing in bending.

I'm with Steve....I don't inderstand using that style in that location. I do understand that X configuration as I used it in my cage with the door bars, but in that area of the cage I'm not seeing a benifit.

[blkaplan]

BTW...what size tire and what suspension? OTE's wouldn't be a problem with some dirt stockers. Dayum!

The spec wheel size for SPEC3 is 15x7. I believe tire sizing is open.

This weekend we just had the stock suspension on the car but we have the spec suspension on order waiting to be installed.

I dont have the full details on whats coming but i know it involves Koni inserts, Vogtland Springs, Vorschlag camber plates, subframe reinforcement kit. I have no clue if those brand names are spelled correctly?

[Steve J.]

Ah, I see the flares, thats cool. Not diggin the little branding discs, but to each his own, something to be recognized for at the local track i suppose. With the capabilities it sounds like you have, I rpob would have saved time and just laser cut the design into the sheet, and then had a male/female die press flare the hole and stretch the disc. There is deep draw software that will calculate the amount of material you need to add to compensate for the flare. I used it to create an aluminum soap dish container (don't ask lol). It works flawlessly though.

What kind of laser cutter do you have (or have used)? I know some people who have made some DIY CNC laser jigs that work awesome.

I'm interested in where the figures are coming from, as i like to have data compare to.

I'll do up a comparison in SW right now to get a number and see how close the data is, its never right, its just good for comparison.

I'm always worried about dirt and rubber getting inside the gussets lol maybe I should have some mesh discs laser cut with jaffster in the center, the jaffster has to be good for 7.001% i'm sure.

[blkaplan]

Ah, I see the flares, thats cool. Not diggin the little branding discs, but to each his own, something to be recognized for at the local track i suppose.

What kind of laser cutter do you have (or have used)? I know some people who have made some DIY CNC laser jigs that work awesome.

I'm interested in where the figures are coming from, as i like to have data compare to.

I'll do up a comparison in SW right now to get a number and see how close the data is, its never right, its just good for comparison.

I'm always worried about dirt and rubber getting inside the gussets lol maybe I should have some mesh discs laser cut with jaffster in the center, the jaffster has to be good for 7.001% i'm sure.

Its Amada 4x4, pretty nice little machine only does upto .25" steel but its very good with the thin stuff.

I ran FEA on the gusset plates with and with out the inserts in Pro-Mechanica to determine if they would do anything for stiffness because i knew people would ask.

[Steve J.]

Even with the flares they add 7%, hmm. Where was the force being applied?

[getfast]

The spec wheel size...

I dont have the full details on whats coming...

It's a spec wheel and tire TBA (brand and size.) As is the suspension kit until the rules are released, eh?

Jon

[theruss1an1]

Glad to see some spec3 builds! Cant wait for the series to get started.

-Serge

[Steve J.]

I just ran some FEA, and without gussets, the X is 5x stronger. However, with the gussets, they are very similar, although you are now relying on the gussets for the majority of the rigidity, and they can/will fatigue at some point, although we're talking such small beans here, its not a big deal. But of course it will start to deform and yield before the bend, as it has extra material to absorb the load and deform. With the "X" it needs to compress a tube until it buckles, or bends...and again with gussets on all sides, we're talking some serious loads required.

Looks really nice though, I like seeing curves in cages...hence all the trouble I am going through for the Apillar design I want. probably only marginally "better," but it has that extra wow cool factor but it is 100% function, as it allows for higher torsional rigidity and more room for egress.

[e36quickbrick]

yeah.....uh.....the official rules are not out yet....but, i can tell you that spec parts have been decided....with potential for additional spec parts (upper strut bar, etc.).....and i can not confirm or deny the suspension pieces ben referenced - but, if those are the parts for the series, I'll be very happy. Chris Cobetto, Barry Battle, Jon Felton and I tested the heck of the SPEC3 prototype (a 4 door) and all of the mention parts were rather impressive.

the tire size will not be open....

rules will be out very, very soon. all the sponsors and manufacturers are currently in the process of getting new numbers in their systems.

the SPEC3 car you in this thread is actually mine. and i have to say, ben and travis have been amazing to work with on this project. they far exceeded my expectations and as you can see by the end product, this does not look like their first BMW project. the photos are nice, but to see the cage in person is even more impressive - it really shows the passion and perfection that goes into their work.

i'd seriously recommend ben and travis to anyone building any cage in any car. they are very reasonably priced considering what you get. ben also makes some killer custom suspension bolt on goodies and super lightweight wheel spacers.

as for the SPEC3 series - i think it is going to be a great series if it attracts the same types of drivers and sponsors that SPEC E30 did. the SPEC E30 series is awesome - great cars, great drivers, good sportsmanship and great competition. while i am rambling......i've heard some people groan that SPEC3 will take away from SPEC E30 and that it will hurt the SPEC E30 series. not at all. not even close. SPEC E30 will remain as strong as ever - and for good reason. SPEC3 will be a success as well - but not at the expense of any other existing series.

[getfast]

i've heard some people groan that SPEC3 will take away from SPEC E30 and that it will hurt the SPEC E30 series. not at all. not even close. SPEC E30 will remain as strong as ever - and for good reason. SPEC3 will be a success as well - but not at the expense of any other existing series.

I agree 100%. Having driven both the Spec3 prototype and the "winningest" Spec E30 in the country (Cobetto's) at VIR recently, I can tell you that the cars do feel pretty different. They are variations on a theme, or if you prefer, they are like icecream (doesn't matter what flavor, they're all delicious, and some people will like one more than another.) Stupid analogy I know, but it's true. I don't think (m)any Spec E30 people will be jumping ship. I think Spec3 will just give current and future racers another place to play... and I can't wait to be a part of it!

No donor car yet - but at least I know who's building my cage (see pics above),

Jon

[blkaplan]

I just ran some FEA, and without gussets, the X is 5x stronger. However, with the gussets, they are very similar, although you are now relying on the gussets for the majority of the rigidity, and they can/will fatigue at some point, although we're talking such small beans here, its not a big deal. But of course it will start to deform and yield before the bend, as it has extra material to absorb the load and deform. With the "X" it needs to compress a tube until it buckles, or bends...and again with gussets on all sides, we're talking some serious loads required.

Looks really nice though, I like seeing curves in cages...hence all the trouble I am going through for the Apillar design I want. probably only marginally "better," but it has that extra wow cool factor but it is 100% function, as it allows for higher torsional rigidity and more room for egress.

The bend approach does not work without gussets. the weld and stress distribution is over to small of an area to make it effective, if you aren't going to gusset X is the way to go. BUT, if you are going to gusset one of the reasons i like the bends w/ gusset combo is you have two continuous pieces of tubing running to the main hoop and to the rear stays. In my mind the deformation of the sheet metal gusset is a far superior mode of failure, In an big impact the gussets will absorb much more energy then a buckling tube will.

The size of the gussets makes them very strong and they wont see loads any where close to a detrimental fatigue level with normal track use,

[cafcwest]

the tire size will not be open....

between the title sponsor of the sanctioning body and the spec'ed wheel size, the tire size/manufacturer shouldn't be too huge a jump of imagination.

[vmwerks]

Nice build... we have our Spec3 donor in white ready for the rules to be released... PAGING Mr. Cobetto!!!!