C3/4/5 frankenstein frame

[vette427sbc]

Removed from the mold:







The stock wiper door sans trim, hardware, etc is 74oz. The carbon version is 5.5oz. Thats before I add the nutserts and a few areas of reinforcement, so Im going to guess it will be under 15oz by the time its functionally ready. The stainless trim stiffens it up considerably, but its definitely flimsy. Im happy with it so far though.

cool parts. In my bike-racing days, we spent a great deal of time getting the dimensions of our bikes so that we didn't have to bring them to races... I use the same technique on cars, find what you like, measure all the various positions - then you can transfer it to whatever you're driving and you get up to speed a lot faster... even in wildly different cars

Thanks! I feel that theres very few reasons to NOT make something adjustable, especially when it comes to driver comfort/functionality. I bet small changes are even more noticeable on the bikes.

 

[BBShark]

Looks good. I would like to see how you add mounting bosses etc. to the underside. I've never done anything other than fiberglass repairs and have never seen how you actually make a part.

 

[69427]

Here’s why I send my car 6+ hours away to this guy;

Hollow stainless hardware

I somehow missed this earlier post of yours. Here's a belated :thumbs: .

I've drilled "cups" into the tops of several bolts when I'm having some moments when I can't figure out what my next move is when trying to solve a problem on the car. It helps me compensate for otherwise unproductive time in the garage.

Years ago I rifle drilled the bolt that holds the parking brake pulley onto the transmission crossmember, but that's the extent of that kind of work on my part.

Your post has prompted me to look into making a jig, and rifle drilling 3/4 of the length of the intake manifold bolts (leaving the tops still solid, to keep from allowing liquids to get down into the head thread holes). This would take a small bit of weight off the top of the engine, and should be an economically efficient alternative to lightweight titanium bolts.

 

[vette427sbc]

Looks good. I would like to see how you add mounting bosses etc. to the underside. I've never done anything other than fiberglass repairs and have never seen how you actually make a part.

I was going to put a nutsert in backwards (finish side on the outside) and then make an aluminum spacer for the wiper door mechanism to rest against. My other plan is to machine a piece of aluminum with the holes threaded in that and bond it to the inside of the door. Stronger, but potentially heavier.

I somehow missed this earlier post of yours. Here's a belated :thumbs: .

I've drilled "cups" into the tops of several bolts when I'm having some moments when I can't figure out what my next move is when trying to solve a problem on the car. It helps me compensate for otherwise unproductive time in the garage.

Years ago I rifle drilled the bolt that holds the parking brake pulley onto the transmission crossmember, but that's the extent of that kind of work on my part.

Your post has prompted me to look into making a jig, and rifle drilling 3/4 of the length of the intake manifold bolts (leaving the tops still solid, to keep from allowing liquids to get down into the head thread holes). This would take a small bit of weight off the top of the engine, and should be an economically efficient alternative to lightweight titanium bolts.

:thumbs:

There are certain Ti hardware sizes and types that are somewhat reasonable on Mcmaster... Although still more expensive than what it would cost to rifle drill your existing bolts. The guy that did the original cage in my car has a front engine dragster that he races. I told him how weight conscious I was with my car and he showed me a pile of his exhaust bolts that he had just rifle drilled... There are few people (most of them on this forum!) who would find that as cool as I thought it was

 

[69427]

.................
:thumbs:

There are certain Ti hardware sizes and types that are somewhat reasonable on Mcmaster... Although still more expensive than what it would cost to rifle drill your existing bolts. The guy that did the original cage in my car has a front engine dragster that he races. I told him how weight conscious I was with my car and he showed me a pile of his exhaust bolts that he had just rifle drilled... There are few people (most of them on this forum!) who would find that as cool as I thought it was

The exhaust bolts are another good place for drilling (up front and up high).

Regarding your other post, the wiper door looks fantastic. You really have my attention on that item.

 

[vette427sbc]

So heres what I came up with for the mounting... Piece of 6061 threaded and riveted to the CF. I also added two more layers on the inside edges to stiffen it up (and it did, considerably!). Ready for some sanding and bodywork!

My old door was pretty beat up and had the threads repaired at one point, but Here is the data I was able to come up with:

inside face to inside face where the arms mount to the door is 43.75" (front and rear holes)
bolt centerline to centerline is ~1.58"
bolt centerline to the top edge of the door is ~.425" (front and rear holes)
outward taper is ~4.7*

Final weight...
7.85oz :yahoo:

 

[vette427sbc]

Almost all the parts collected for the rear hub conversion...
C7 Hub, Dutchman C7 to porsche 934 CV flange and MSI 5/8" coated wheel studs. Just waiting on the Spicer 1350 flange.

 

[69427]

.....

Final weight...
7.85oz :yahoo:

.................

:thumbs:

 

[rtj]

Almost all the parts collected for the rear hub conversion...
C7 Hub, Dutchman C7 to porsche 934 CV flange and MSI 5/8" coated wheel studs. Just waiting on the Spicer 1350 flange.

You are putting these in the c4 suspension? How much machining, or will it bolt in? Looks like some nice parts.

 

[vette427sbc]

You are putting these in the c4 suspension? How much machining, or will it bolt in? Looks like some nice parts.

Yes... lots of machining unfortunately. The hub bolt pattern is different so the caliper bracket will need to have its own (stock) bolt pattern, and then the c7 pattern machined into that. The stub axle will also need to have the 1350 pattern drilled into that for the axle flange.
It’s a lot of work, but if you look at the cost of doing a 31(?) spline C4 bearing/stub axle, this is a no brainer. The c7 conversion will allow me to use better and more readily available parts, and leaves room to upgrade to CV axles and an upper link down the road

 

[BBShark]

Is the C4 and the C7 hub a 31 spline?

 

[vette427sbc]

Is the C4 and the C7 hub a 31 spline?

The stock C4 is 27 spline... I did a bunch of research on the C4 boards and it seems like guys blow up the stub axles more often than the rest of the drivetrain. There is a company that will make you 31 spline hubs and stub axles, but you are still left with a hub that is not as good as the C7 hub. The C7 is 33 spline. I'd really like to be able to launch this car off of a 2 step for autocross but the tire size and torque had me worried that I was going to break the stock stuff in short order.

 

[69427]

Is the C4 and the C7 hub a 31 spline?

The stock C4 is 27 spline... I did a bunch of research on the C4 boards and it seems like guys blow up the stub axles more often than the rest of the drivetrain. There is a company that will make you 31 spline hubs and stub axles, but you are still left with a hub that is not as good as the C7 hub. The C7 is 33 spline. I'd really like to be able to launch this car off of a 2 step for autocross but the tire size and torque had me worried that I was going to break the stock stuff in short order.

I'll admit my ignorance here. What does that mean?

 

[vette427sbc]

Its essentially a selectable rev limiter... you set a "launch" RPM and it will hold that RPM until you release a button, or whatever you have activating it. Popular in drag racing, Im seeing it used more in autocross now as well.

 

[rtj]

You might have a nice niche market there for that rear C4 upgrade.

How long before autocross guys install line lock and start doing burn-outs before a run? I’m assuming they don’t already. . Since I left Fl, I don’t really attend many Motorsport events(seldom).

 

[vette427sbc]

The only thing keeping this out of production is the stub axle... I would have to commission Strange, Moser, etc to manufacture a run of the proper length 1350 stubs. My plan for CV's down the road is why I didnt just do that from the beginning.

 

[vette427sbc]

A bit of progress... the new caliper bracket/hub adapter Version6.0 is 3d printed for final mock up. So this is a Stoptech ST40, C7 Z51 front rotor, C7 rear hub on a late C4 knuckle. Off to the CNC





I may end up doing the CV conversion this time around after all... Going to see how difficult it will be to add the provisions for an upper link. It doesnt look like ill be driving it this season anyway

 

[mfain]

I may end up doing the CV conversion this time around after all... Going to see how difficult it will be to add the provisions for an upper link. It doesnt look like ill be driving it this season anyway

I don't know if Detroit Speed will sell these uprights separately. They are part of their C-2/C-3 Decalink. They are made for a C-2/C-3, use C7 hubs, and c5/c6 brakes. Their full kits use either their proprietary (read expensive) Hammerhead differential or you can use a C-3 chunk with their stub axles that accommodate the CV joints. The whole kit is pretty nice - minimal fabrication for installation, excellent roll center and bump steer geometry, and really nice axles/CV joints. I bought the kit just to use the uprights and axles, but ended up installing the crossmember (in a C-1). You might save a little money by piecing something together, but it would be hard to beat their engineering.

 

[vette427sbc]

I don't know if Detroit Speed will sell these uprights separately. They are part of their C-2/C-3 Decalink. They are made for a C-2/C-3, use C7 hubs, and c5/c6 brakes. Their full kits use either their proprietary (read expensive) Hammerhead differential or you can use a C-3 chunk with their stub axles that accommodate the CV joints. The whole kit is pretty nice - minimal fabrication for installation, excellent roll center and bump steer geometry, and really nice axles/CV joints. I bought the kit just to use the uprights and axles, but ended up installing the crossmember (in a C-1). You might save a little money by piecing something together, but it would be hard to beat their engineering.

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...sigh
If I can (more likely, the fab shop that its at right now) come up with a solution to get that upper link on the C4 knuckle, Im all for keeping it. The Deca-link knuckle could be a good solution for me if that doesnt pan out. Number one problem with a project that takes this long is that new ideas and products come out AFTER Ive aready designed everything else around a (now) outdated part.
Hell, Im already thinking about ditching the 427 and 6 speed for a SB2.2 and BMW DCT with a clutch pedal. :ill:

 

[BBShark]

I may end up doing the CV conversion this time around after all... Going to see how difficult it will be to add the provisions for an upper link. It doesnt look like ill be driving it this season anyway

I don't know if Detroit Speed will sell these uprights separately. They are part of their C-2/C-3 Decalink. They are made for a C-2/C-3, use C7 hubs, and c5/c6 brakes. Their full kits use either their proprietary (read expensive) Hammerhead differential or you can use a C-3 chunk with their stub axles that accommodate the CV joints. The whole kit is pretty nice - minimal fabrication for installation, excellent roll center and bump steer geometry, and really nice axles/CV joints. I bought the kit just to use the uprights and axles, but ended up installing the crossmember (in a C-1). You might save a little money by piecing something together, but it would be hard to beat their engineering.

View attachment 2398

View attachment 2399

Weren't you using a watts link for the rear? I think it was years ago but I thought that was interesting. Never seen it done.