Well I was bored the other day and decided to start a few detail projects for the RX8 (I have a long list of upgrades focusing on different areas...) so I ordered a stock lug bolt and picked it up today... Measured all the specs and ordered a custom set in titanium... This will further reduce un-sprung weight and also look really cool...:cool:

They will be here in about a week; here is a pic of the stock one (Heavy & Ugly)...:eek:

how much weight you think youll drop ?

I would think very carefully before using Titanium for this purpose.

Titanium is about 1/3 lighter than steel and about 2/3 heavier than aluminium. So yes you will lose weight But only a very small amount. BUT Titanium is more prone to fracture and having threads increases this problem. Also Titanium does not Torque well as it is more elastic than steel.

If you decided to continue anyway. Please first let me know what type of Titanium you plan to use so I can do the stress calculations for you.

Thank you,
mtwizard

This has already been done; I don't want to get into to many details at this point... It will be a very well engineered solution...

It is used all the time for wheel lugs especially in racing with very good results...

I will post weight comparisons next week, until then I have some other cool projects I am working on...:)

Here is a picture of another application...

well from my experience i have broken a few
either s/t racing,aftermarket wheels before on my rx7.
its best just to leave oem ones.
ive had to drive to judge ito shop on 2-3 studs
and one time had only 1 bolt at that time, just towed it.
but i use to be a maniac back then :)

Tried them on my supra.After 4 breaks i dumped em.I had 400lbs of torque with that to but point still remains.

hey dave
i didnt know you also joined the dark side before :)

Its talking to me again Kel.
The DEMONS make it stop.
If i dont find FI soon im returning.

Not all titanium bolts are created equal, I have used them before with very good results; have never had one break on me... If you use the right titanium alloy...

I am sorry titanium lugs are just silly.

$$$$$ to save a few oz per corner?

And who the hell sees the how ugly your stock lugs are? They are covered at all times.

Don't mean to be rude. But you would probably get better performance upgrade by removing the sun visors or something like that.

-Mr. Wigggles

With the new brakes and the other set of wheels I will be buying just for track use it will be a nice extra... And I am not concerned about $$$$$... Also it is more than a few oz...

Originally posted by MrWigggles
Don't mean to be rude. But you would probably get better performance upgrade by removing the sun visors or something like that.

-Mr. Wigggles

The sun visors would not classify as unsprung weight. :D

Originally posted by cortc
And I am not concerned about $$$$$...

You dont hear that a lot

I am curious which grade of Ti?

Speaking of Titanium alloys, has anyone heard of this crazy "Liquidmetal" stuff, titanium w/ the crystal structure of glass?

www.liquidmetal.com

Holy crap...2x the yield strength of titanium or stainless, with further improvements anticipated. Absolutely NOT brittle at all, in fact it would make an excellent spring material--check out the bouncing ball video! It can be cast with much more detail and accuracy than conventional metals, so for some parts you might not have to machine them. It can also apparently be used to make a metallic styrofoam!

The "holy grail" of their research is of course to achieve the same glassy crystal structure, only in steels and aluminum.

http://www.liquidmetal.com/images_2/tech_cast_alloy.gif


Hmm...if a regular 18" aluminum wheel is say...20 lbs., then I would imagine you could make LiquidMetal wheels that were 10 lbs. each :drools:...expensive yes, but you might not need any machining, they come out of the mold super shiny, and eventually the price is bound to drop.

Yeah I was reviewing this material for a product I was working on. My company tends to like proven technology and the price was too high. Cool stuff nonetheless.

Liquidmetal Discussion on forum (http://www.rx8club.com/showthread.php?s=&threadid=11648&highlight=liquidmetal)

Suppose to "cast" like plastics. I wonder how thin of a wall you can make. The increase strength really allows for a thinner/lighter design.

We might use T4, and the torque specs would be 60-65fp...

There is nobody that appreciates weight reduction more than me. However, I am scared this project is doomed to fail when applied to a street vehicle. Grade 4 Titanium is not particularly strong and as stated earlier all titanium alloys are notch sensitive. Notch sensitive means that titanium has poor impact resistance if it has a groove or hole or any severe shape change. A wheel stud is threaded (bad notch) and is subject to significant impact loads from potholes and banging into curbs, etc.

Instead of the Ti wheel studs why don't you make the lug nuts of Ti? They are not subjected to the impact loads that the stud sees.

The lugs will work fine with my application...

So is it www.mettec.com that will make them?

Well the lugs are in production will have them in about a week... Will post pics and install as soon as they arrive...

:eek: i want liqid metal rotors and apex seals for my fd damn thats sweet stuff :D. i thougtht glass was goin to shatter the ball got so i pithced at the end.
joel

How easy are the bolts to remove as I've had to put 3mm spacers on to keep my rims away from the brake calipers. Bit concerned about the length of bolt that comes through the rim to screw the nuts into. Not too bad, as the nuts screws round 4-5 times, but would feel happier with longer blots. If they are easy to replace I may do it - but just normal steel!

which other wheels are you getting?

Sorry, been on holiday, there is a thread on here with them, they are from an italian company, rebadged by www.wheelmania.co.uk - Vermont.

I looked up liquidmetal, the results on this site basically said the liquidmetal knife sucked ass.

http://www.physics.mun.ca/~sstamp/knives/clark_model_10.html

The performance would benefit greatly from a decently tough carbon steel, something like A2 or O1, both of which are also far harder than LM1
BTW, LM1 is made up of about 41 percent zirconium, about 14 percent titanium, about 12.5
percent copper, about 10 percent nickel, and about 22.5 percent beryllium

Speaking of Titanium alloys, has anyone heard of this crazy "Liquidmetal" stuff, titanium w/ the crystal structure of glass?

Hmm...if a regular 18" aluminum wheel is say...20 lbs., then I would imagine you could make LiquidMetal wheels that were 10 lbs. each :drools:...expensive yes, but you might not need any machining, they come out of the mold super shiny, and eventually the price is bound to drop. Drool, is RIGHT.

Cort, if money is no object, will you buy me some liguid metal wheels? :D

I was on another board and someone had posted a link to a story which basically said that they've started their first bit of casting using a primarily aluminum alloy. As in, "not based primarily on exotic/expensive alloys". Too bad the company management is having trouble getting their shit together.


Oh and it can be made into a sort of "metallic styrofoam":

http://www.liquidmetal.com/news/dsp.news.04x204.asp

Better yet, it can be readily made into a foam. “With most metals that’s difficult, because the bubbles want to rise to the surface of the molten metal,” says Johnson. The fact that amorphous metal is thick and like plastic when molten permits the formation of a foam panel that is 99 percent air but roughly 100 times stronger than polystyrene. A sandwich made of two thin sheets of amorphous metal flanking amorphous foam would be strong, light, insulating, fireproof, bug-proof, rustproof, sound dampening, and difficult to penetrate with bombs. Such panel could form buildings, ship hulls, airplanes, and car bodies.


Actually, while they're at it...they can whip up some liquidmetal brake rotors too, along with my wheels. Aren't pretty much all brake rotors still just carbon steel?

Ok, the prototype bolts should be here Friday; they have been tested along with a stock one and proved to be very strong and much lighter. I will post more details when they get here along with pictures and the install...

i'm not concerned with $$$$ either...but that's cuz my wife spends it all, so there's no $$$$ to be concerned with :D

Along with these I am going with the SSRs and am looking for some two piece brake rotors...

If I can't find some I will have some made...

cortc go to www.dba.com.au and request they make some :)

I already have but they arn't planning in it to the new year :(
maybe a few more voices and they will do them sooner.

I would want front and rear...

let them know. they have a good rep with the modifying community in .au and have represntatives on the major forums.
they told me 3kg in weight could be saved.

I will contact them and see if I can get them to make them sooner...

Ok, I just received the prototype lug nuts, very nice! I will take pictures and post tonight; the install is tomorrow as well as some specs...

They weigh much less than the stock ones and we made them out of T4; they are forged with machined threads... The production ones will be completely forged including the threads and heat treated...

We tested them against the stock ones for several load factors including shear and they held up quite well (All test came in within 93% and a few were equal or better...) so now I will road test them...

They came in @ .96oz each or a set of 5 @ 4.8oz total weight; I will weigh the stock ones and post those weights tonight...

Ok, the stock ones are just over 2oz each (2.1oz) will double check tonight... So that is 10.5oz total for 5... The titanium ones are 47% lighter and they include a really nice speed starter; pictures should be up tonight...

Well some rough numbers:

Savings per corner = 5.7oz
Total savings for all four corners = 22.8oz or almost 1.5lbs savings...

These are really cool, lighter, about 5mm longer, strong and have a nice speed starter...

Install and practical testing begin this weekend and the productions ones wil be even stronger... (Completely forged and heat treated...)

I am working out some qty pricing so stay tuned...

I am working out some qty pricing so stay tuned...

That's my man. Appreciate you looking out for us.

A few pictures of the prototypes, they are a reality; installation to follow...:)

Sweetness !

Ok, just got done with the install... Very nice and they are very strong...:)

A few more, also installed the MS brake lines...

Just a few more pics...

SWEETNESS ! .............again.

Good job, they look great. What was the final cost ?

You have to remove the front and rear spindles and support them around the lugs to remove the stock ones... You can press them out or hit them with a hammer carefully; you cannot hit them with a hammer or put impact pressure on the bearings as you will destroy the bearings and the bearing chase...

The fronts are easier than the rears as the fronts can be removed bearings and all with four bolts (Very cool...), the rears have to come apart...

cgrx: Thanks, I did all the drawings and specs myself so that saved me some dollars, the prototype came out to about U$620.00... The production ones will run about U$300.00-320.00 for a set of 20... if I make enough I can probably get them down to U$250.00-275.00...

This is the only RX8 right now with titanium lugs, and with the new wheels and two piece brake rotors as well as the light weight forged lug nuts she is going to handle and spin up real nice...

Plus it looks really cool and should rack up a bunch of points at the shows...:)

Ok, did some more calculations on weight reduction including the light forged lug nuts I have on the car...

Stock lug nut 2oz (2x5=10oz per corner) 10x4=40oz or 2.5lbs...
Forged lug nuts 1oz (1x5=5oz per corner) 5x4=20oz or 1.25lbs...

That is another 1 1/4 lbs savings in unsprung rotating weight, including the 1 1/2 lbs savings of the titanium lug bolts that is a total of 2 3/4 lbs...

When rotating at high speed that weight increases by a factor of 7 or 19.25lbs...

I took the car out for a ride with the stock lugs and bolts before doing the install and then with the titanium lug bolts and lightweight forged lug nuts and there was a difference you could feel... With the new wheels and two piece brake rotors this should really lighten things up.

So for those that ask, does reduced unsprung weight or rotating unsprung weight reduction make a difference?; the answer is yes...

Are these "commerically pure" Ti, or an alloy? Also, are they annealed or is there a specific temper to the metal (AMS spec maybe?)

They are T4 very pure (High Oxygen), they are forged then heat treated...

Grades Description
Grade 1 Unalloyed titanium, low oxygen, low strength
Grade 2 Unalloyed titanium, standard oxygen, medium strength
Grade 3 Unalloyed titanium, medium oxygen, high strength
Grade 4 Unalloyed titanium, high oxygen, extra high strength
Grade 5 Titanium alloy (6% aluminum, 4% vanadium)
Grade 7 Unalloyed titanium plus 0.12% to 0.25% palladium, standard oxygen, medium strength
Grade 9 Titanium alloy (3% aluminum, 2.5% vanadium), high strength. Mainly aerospace applications
Grade 11 Unalloyed titanium plus 0.12% to 0.25% palladium, low oxygen, low strength
Grade 12 Titanium alloy (0.3% molybdenum, 0.8% nickel), high strength
Grade 13 Titanium alloy (0.5% nickel, 0.05% ruthenium), low oxygen
Grade 14 Titanium alloy (0.5% nickel, 0.05% ruthenium), standard oxygen
Grade 15 Titanium alloy (0.5% nickel, 0.05% ruthenium), medium oxygen
Grade 16 Unalloyed titanium plus 0.04% to 0.08% palladium, standard oxygen, medium strength
Grade 17 Unalloyed titanium plus 0.04% to 0.08% palladium, low oxygen, low strength
Grade 18 Titanium alloy (3% aluminum, 2.5% vanadium plus 0.04% to 0.08% palladium),
Grade 19 Titanium alloy (3% aluminum, 8% vanadium, 6% chromium, 4% zirconium, 4% molybdenum)
Grade 20 Titanium alloy (3% aluminum, 8% vanadium, 6% chromium, 4% zirconium, 4% molybdenum) plus 0.04% to 0.08% palladium
Grade 21 Titanium alloy (15% molybdenum, 3% aluminum, 2.7% niobium, 0.25% silicon)
Grade 23 Titanium alloy (6% aluminum, 4% vanadium, extra low interstitial, ELI)
Grade 24 Titanium alloy (6% aluminum, 4% vanadium) plus 0.04% to 0.08% palladium
Grade 25 Titanium alloy (6% aluminum, 4% vanadium) plus 0.3% to 0.8% nickel and 0.04% to 0.08% palladium
Grade 26 Unalloyed titanium plus 0.08% to 0.14% ruthenium, standard oxygen, medium strength
Grade 27 Unalloyed titanium plus 0.08% to 0.14% ruthenium, low oxygen,low strength
Grade 28 Titanium alloy (3% aluminum, 2.5% vanadium) plus 0.08% to 0.14% ruthenium
Grade 29 Titanium alloy (6% aluminum, 4% vanadium with extra low interstitial elements (ELI) plus 0.08% to 0.14% ruthenium

List of Titanium Grades

ASTM Grade Alloy Composition Min. Tensile (KSI) Min. Yield (KSI) Modulus of Elasticity (PSI-106)
1 Unalloyed Ti ("Pure") 35A 35 25 14.9
2 Unalloyed Ti ("Pure") 50A 50 40 14.9
3 Unalloyed Ti ("Pure") 65A 65 55 14.9
4 Unalloyed Ti ("Pure") 80A 80 70 15
5 Ti-6Al-4V13012016.4
6 Ti-5Al-2.5Sn12011516
7 Ti-0.15Pd504014.9
9 Ti-3Al-2.5V907013.1
10 Ti-11.5Mo-6Zr-4.5Sn1009014.9
11 Ti-0.15Pd352514.9
12 Ti-0.3-Mo-0.8Ni705014.9
13 Ti-0.5Ni-0.05Ru402514.9
14 Ti-0.5Ni-0.05Ru604014.9
15 Ti-0.5Ni-0.05Ru705514.9
16 Ti-0.05Pd504014.9
17 Ti-0.05Pd352514.9
18 Ti-3Al-2.5V-0.05Pd907015.3
19 Ti-3Al-8V-6Cr-4Zr-4Mo11511014.9
20 Ti-3Al-8V-6Cr-4Zr-4Mo-0.05Pd11511014.9
21 Ti-15Mo-2.7Nb-3Al-0.25Si11511014.9
23 Ti-6Al-4V ELI11511016.3
24 Ti-6Al-4V-0.05Pd13012016.4
25 Ti-6Al-4V-0.5Ni-0.05Pd13012016.4
26 Ti-0.1Ru504014.9
27 Ti-0.1Ru352514.9
28 Ti-3Al-2.5V-0.1Ru907013.1
29 Ti-6Al-4V-0.1Ru12011016.3

Most of the grades are of alloyed type with various additions of for example aluminum, vanadium, nickel, ruthenium, molybdenum, chromium or zirconium for the purpose of improving and/or combining various mechanical characteristics, heat resistance, conductivity, microstructure, creep, ductility, corrosion resistance etc. etc.

Palladium (Pd) and ruthenium (Ru), Nickel (Ni) and molybdenum (Mo) are elements which can be added to the pure titanium types in order to obtain a significant improvement of corrosion resistance particularly in slightly reducing environments where titanium otherwise might face some problems due to insufficient conditions for formation of the necessary protective oxide film on the metal surface. The formation of a stable and substantially inert protective oxide film on the surface is otherwise the secret behind the extraordinary corrosion resistance of titanium .

The mechanical properties of commercially pure titanium are in fact controlled by "alloying" to various levels of oxygen and nitrogen to obtain strength levels varying between approximately 290 and 550 MPa. For higher strength levels alloying elements, e.g. Al and V have to be added. Ti3Al2,5V has a tensile strength of minimum 620MPa in annealed condition and minimum 860 MPa in the as cold worked and stress relieved condition. The CP-titanium grades are nominally all alpha in structure, whereas many of the titanium alloys have a two phase alpha + beta structure. There are also titanium alloys with high alloying additions having an entire beta phase structure. While alpha alloys cannot be heat treated to increase strength, the addition of 2,5% copper would result in a material which responds to solution treatment and ageing in a similar way to aluminum-copper.

thanks.

btw, the only reason I put commercially pure in quotes is cause that's how it's referred to in the mil spec handbooks for metals. The type of Ti that I'm most familiar with is the grade 5 (6Al-4V), which seems to be the most common in various aerospace (civilian and mil) applications. Sometimes I get a little dissapointed when I try to find hardware in the real world (gotta keep reminding myself that the bolts I use at work start above the strength of "grade 10" commercial hardware, and go up from there...)

you wouldn't happen to know the spec for the steel used in the stock lugs, would you?

I am looking for the specs on the stock ones, as soon as I have will post...

Well been testing the car for a few days under different conditions and load and the bolts have done very well... Absolutely no problems and they are very strong; I can feel the difference with them on and with the new lighter wheels things should really start feeling good...:)

Ok, all the testing is done and we are going to do a production run of 10 sets of 20, will discuss with Omicron and post details later...

about how much are they going to run??? if not to bad, count me in for a set!

I am finalizing pricing and will post once I have everything squared away... The production ones will have forged heads rolled threads and they will be heat treated, even stronger than the prototype set...

The lugs bolts have speed starters on them for function, they also look really cool and if you ever use open ended lug nuts won’t ever rust or corrode…

Sounds like an interesting project, nice work. I'm curious though, under what kind of situations do lug nuts fail and how do these failures manifest themselves? Is it catastrophic, like a wheel coming off on a highway, or somehting recoverable. If one fails can it be easily replaced? Or does continued operation affect other parts?

All wheel lug bolts can fail but they usually fail independently; one at a time... The only way a wheel is coming off is if you hit something really hard (Really hard as in major damage to other components as well...) and even then it usually comes of at the spindle or the complete suspension assembly comes off...

If one fails it can easily be replaced and you can buy them individually if required...

These will be basically as strong as the OEMs while being much lighter and corrosion resistant...

what is the difficulty level of changing out the bolts???

Not sure if this has been mentioned before, but a google search for "Titanium lug nut" shows this link:

http://www.mettec.com/latemodel.htm

Specific RX8 stud size may be an issue here (I have no idea what size is needed), but off the shelf could be an alternative to custom titanium lugs...

The whole project is just amazing. I'm in for the group buy.
The price given a few weeks back by cort seems reasonable.

Mettec, does not have the sizes for the RX8 only Sprint car racing sizes...

Difficulty is a 5/6 on the 1-10 scale...

Ok, received approval from Omicron so the group buy will be posted tonight...

Hey Carlos, you think you can make me some Titanium Hurricane shutters ;)

Alex, right after I make mine...:)

Ok, as promised here is the group buy link...:)

http://www.rx8club.com/showthread.php?p=520435#post520435

Cortc,
What do you do about wheel locks?

I recommend some nice lightweight forged chromoly or aluminum open or closed ended lug nuts... The Kyokugen are very good and a set runs about U$49.00 + shipping, for those who don't want the hassle of getting them I can hook them up...

Here is a write-up on the Kyokugens:

http://www.rx8club.com/showthread.php?t=29177

pardon my english but when you say '...I can hook them up...' you mean you'll include the lug nuts in the group buy, for all those that believe in your projects:)

What I mean is I can include them in the kit for U$49.00 (My cost...) and no additional shipping... You will have lighter and stronger lug nuts as well...

^^To tell you the truth, I wanted to say exactly the same thing^^

I just wrote the whole thing wrong... still, nice to hear it!

These are still available if anyone wants some...

cortc, you mean you still have the ti wheel bolts or the pulleys?

The lug bolts are available if enough members want it, check the group buy section...