I hope the pace on track is better than pace of this project

[kverges]

Solid core are about 50% stronger, but the adhesive is much stronger in shear than either. I really don't expect a problem. With shear strengh of over 4,000 psi and in excess of 10 square inches on each bond, the 40,000 lb of shear force (and that would be a differential force at the junction) to break the bond will have far more dire consequences than just the bond problem.

It will be interesting to see how this holds up to vibration more than anything else.

[turbophil]

Ya, I hear ya... Probably overkill... Just one of those things where it's like, if you're going to do it at all, may as well use a "real" rivet rather than a body panel rivet... I don't mean to make a mountain out of mole hill. Looks like you've thought all this through pretty well and don't mean to nit-pick...

Take care,

TP

[9and3]

Rivets and adhesive to mount a cage! At a minimum, I'm surprised that any sanctioning body would issue a log book for this.

[Conan]

Originally Posted by 9and3

Rivets and adhesive to mount a cage! At a minimum, I'm surprised that any sanctioning body would issue a log book for this.

I kinda agree. Even assuming the adhesive is more than strong enough, if the rule book says it must be welded, then they won't allow the adhesive. When I got my Porsche tech'd the first time, they didn't like the fact it was a bolt in cage -- even though the rules allow it. So I can't imagine anything outside of the book to pass. Good luck, though. Project seems really cool!

[kverges]

I am hoping the voice of reason prevails. If bonding and screwing is satisfactory for the chassis, and you obviously cannot weld ferrous to non-ferrous materials, then the strongest bond should be best. I do not think a through bolt is more rigid or stronger than this bond. First, the bolt(s) will concentrate all shear force on just the through-hole in aluminum that is usually no more than about .1 inch thick, second, a 7/16" grade 8 bolt has a shear strength of about 13,500 lb (way stronger than the aluminum to which it is bolted), whereas the adhesive has over 40,000 lb of shear strength. Similarly, the tensile strength of the bond is equvalent to about 3 7/16 bolts, but those bolts will readily pull out of the aluminum due to the stress concentration at the hole. This bond will distribute the force better and from an engineering perspective has to be stronger than using bolts.

Go look at a 737; it uses riveted joints everywhere, especially in patches. Ever notice the fuselage repair patches near the entry door? Big bolts and big holes concentrate stresses; lots of surface area and smaller fasteners distribute stresses better.

Finally, after some use, bolted holes will ovalize and the car be more flexible than bonded joints like this.

It will probably take some convincing, though.

I'd take this cage over bolting in a cage into a Porsche unibody any day. If the car is ferrous, a weld in cage is the only way to go. That was not an option and I picked what I personally think is safest. It will rarely race anyway and will spend most of its life lapping at MotorSport Ranch or broken in my garage.

[AZReason]

How big of spacer are you using in the rear for the 6ul's. I was considering a 10mm spacer with a hubcentric protusion.

[xtn]

Solid rivets? How the heck would he get on the other side to buck them?

[kverges]

No spacer at all on the rear 6 ULs. Need 15 mm on front to clear the calipers, so I may stay with Rotas in front after all and use the fronts for my SM.

Solid core blind rivets exist; as I understand them the internal rod used to pull them pops off flush with the surface, leaving that much more materail to bear shear loads. harder to find these items.

[turbophil]

Correct. On solid core blind rivets the core rod breaks off above the rivet head and then you trim the core down flush with some nips and finish-file the sharp edge. They're considered structural rivets for racing purposes and completely acceptable to be used in sheer. I believe must of unions on our frame have them (I haven't taken the time to closely examine the rivets on our frame, so just a guess).

Hollow core rivets (like the ones you get at home depot or hardware store) are typically only used for body panels or other non structural items on a race car...

Availability: McMaster is your friend

Cheers,

TP

[Cardinal]

I can't believe they wouldn't allow that. It looks like he scored the substrate, so there's plenty of tooth there. I'd rather have the adhesive than a weld any day. Glue and rivets, the old belt n suspenders approach. If that system is good enough for jetliners, I'd assume it's good enough for a car.

If common sense comes out on top, kverges will be good to go.

[kverges]

Track debut today and no destructive problems. In ambient temps near 90, coolant stayed at under 200 deg F, Oil under 225 deg F, and Intake air temp peaked at 113 deg F at 10 psi boost. Logged oil pressure did drop to 30 psi in spots, but my beacon was not picking up so it was real hard to tell if that was just due to revs dropping on shifts or G-loads.

Bad news was that the LSD I tried (now I wonder if it was really installed) spun the crap out of the inside rear wheel in anything tight, but then again I have not done any suspension setup as I am awaiting the toe link fab work to be completed.

Fuel level was all over the place, so I do not know if my fuel starvation fix really works, although the car did not starve for fuel.

The Hydra auto tuning worked well and kept A/F at a conservative 11:1 under 10 psi boost. The Hass turbo hard parts (actually only the manifold and turbo with my mods) held up fine, albeit it was under 1 hour on track today so time will tell.

I need to get the suspension set up, may need to get adjstable sway bars (they are stock base model bars right now with track pack springs and dampers as part of the overall grab bag of internet deals that make up the car).

Then I need to figure out how the hell to tune the cam timing map, although the base map from Hydra EMS felt good and did not have the abrupt cam switch feel of the stock car.

Overall I am pretty pleased with a first outing since nothing exploded or fell off.

[fishguy]

congrats,
it must feel good to get it out onthe track after all the hard work you put itno the car.

[AZReason]

Great job getting the car on track. Seems like you have way too much tire and horsepower for the track pack springs. If you need a source for 1 7/8" springs up to 600 lbs/in, send me a PM.

[Shine]

Keith (kverges),

Congratulations on your Spec Miata victories! That's an impressive string of victories to pull off (15!)! Good luck at the Runoffs.

[1986esprit]

looks pretty whicked. i noticed in a picture that there is a miata in you garage you race that too?

[Shine]

Originally Posted by 1986esprit

looks pretty whicked. i noticed in a picture that there is a miata in you garage you race that too?

see post immediately before yours.

[kverges]

Yes, I race SM and have a fledgling Turbo SM series I try to get going and race my own car. I am sold on turbo track/race cars right now, although they do require special car and feeding to be reliable.

Compared to my Miata turbo cars, this project is designed to make a bit more power, get weight down, add some aero, and most importantly keep running costs sensible. I am still waiting on the revised toe links with heim joints to be finished, and have a problem with too much oil coming from the valve cover (I may have already taxed the engine with 10 psi boost and stock internals). The ABS light is on, so I need to have that diagnosed (the extreme gutting of wiring harness and removal of ECU may be culprits), then get a solid baseilne alignment and corner weight setup done for more testing. I may have to have the spare engine built with lower compression.

I have driven the car at pretty strong pace and it still won't keep up with a 997 GT3 Cup car, but that is my goal. It will take a bit more power (more boost), and getting the setup right and bugs worked out, but I do think it can be done.

The project will be in slow burn for a while, as right now I am off to Road America to run the MX-5 Cup race this weeeknd, Skip Barber race the next weekend, then back to prepare for the SCCA Runoffs in SM, so the track toy will have to wait until October.

Scott, thanks for the support. It has been a good year, but the Runoffs brings out the best drivers in the best cars and it will be fierce.

[Morty]

Sweet! Good luck on both fronts Keith!

[kverges]

Runoffs are over (and not very successful), so finally back to this project.

The factory track pack coilovers would not go low enough (due to reduced weight of the car), so I had to wrestle with changing springs, further complicated by the fact that the track pack Bilsteins use 1 7/8" coilovers. Many thanks to Doug Evans for pointers.

Also, finally updated the rear toe link, and this was my approach:





Also added the silly front splitter and went back to Rota wheels on front as the 949 Racing wheels interfered with the caliper unless spaced out 15 mm. Also got the ABS problem sorted out The car is now set up at 117 mm front, 122 mm rear ride height, 450 lb/in front, 500 lb/in rear springs, 1 mm toe in rear, 0 toe front, 2.5 deg negative camber front and 2.2 deg negative camber rear to start, on 8" front and 9" rear Goodyear cantilever slicks. With me on board and about 50% fuel the car weighs 1895 lbs, not as light as I would have liked, but the bits & pieces add up. It is all stock running gear, so no lightened rotors or uprights; may try some of that later when the major stuff is working as it should.

That tall center mirror is on purpose - the first time around I noticed that the mirror was right in my field of view looking toward the apex when turning right, so up it went. Details galore will eat you alive on these projects - this one is now into year 3!




Elise Track car :: left side with splitter picture by kverges - Photobucket

I also updated the Hydra to the new 2.6 firmware and software and so there is more tuning to do, but thanks to Al Kibner for sending his cam map, as that should speed that complex tuning issue along. I still need to handle lots of little details, but the car runs & drives and has been on track for basic shakedown and I have reattached the parts that fell off and addressed the oil catch can issue, so inching forward.

Those who come to MSR come check it out most any time. I'll put you to work, though, so be wary!

[knucklehead]

Would love to see a pic of you in the car with your helmet. The rollbar just looks so high, but I get it if you are really tall. Also I was wondering why the deletion of the access panels? I would have just assumed that you would have less drag with them on. The car looks fantastic.