Titanium exhaust tube

[XtremeJ]

Anyone ever worked with Ti?

We are looking at saving some weight on one of the race cars and one of the steps for 2006 is to dump the exhaust from the cat back.

We cannot find anyone to take this on, so I was thinking about bending the tube on the JD3. there are a few concerns.

-Cost and availability of the tube. The few suppliers I have found are $$$ - too expensive to make mistakes
-Bending thin wall tube on the bender. But I was thinking of filling the tube with water, freezing it, and using the ice as an internal mandrel.
-Welding Ti. I can Mig or Tig, but I recall that Ti needs to be welded in an inert enviroment. I remember us using a plastic bubble with the part inside and I think the bubble was argon filled.

Any tips or suggestions?

TIA

Grant

[hotwired]

If I remember Easton makes Ti tubing for mountain bikes, etc. Ti is going to be expensive. Cheapest stuff comes from Russia right now, don't know any sources. You have to be in a weld chamber that's put under vacuum to remove the oxygen and back filled with argon. You might PM cj-etr or Netcott on here, they're both certified to weld Ti.

Dave

[DavidVanVorous]

Anyone ever worked with Ti?

We are looking at saving some weight on one of the race cars and one of the steps for 2006 is to dump the exhaust from the cat back.

We cannot find anyone to take this on, so I was thinking about bending the tube on the JD3. there are a few concerns.

-Cost and availability of the tube. The few suppliers I have found are $$$ - too expensive to make mistakes
-Bending thin wall tube on the bender. But I was thinking of filling the tube with water, freezing it, and using the ice as an internal mandrel.
-Welding Ti. I can Mig or Tig, but I recall that Ti needs to be welded in an inert enviroment. I remember us using a plastic bubble with the part inside and I think the bubble was argon filled.

Any tips or suggestions?

TIA

Grant

Personally I wouldnt use Ti for the application rather a lighter wall chrome-moly because Ti is stress-crack sensitive with heat and cold work. Failing to provide adequate room for growth at themp and following cooldowns will guarantee cracks. Failing to adequately purge will result in porous welds with poor mechanical properties (very oxide prone). We used it in the wheel chair frames at Sunrise Medical but most of the welders were certified to do FDA quality Ti welds and still werent too happy doing them...

BUT iffen yer bound and determined, the tube is best bought full aneal to avoid some of the crack issues during cold working and it really needs an anneal after bending to reduce localised stress. TIG only and has to be purged on both sides to avoid oxidation and resultant stress cracking. This can be a real issue on the setup for the actual weld but they do make cups designed for Ti and other oxide prone weldments if you want to pay the $$$.

D.

[Travis Waldher]

I gotta ask... how much weight are you going to be saving.

Wouldn't it be easier (and more cost effective) to loose weight in other ways?

btw - off topic question why haven't midgets started driving race cars.

[DemoMike]

I think they use type 321 for exhausts....

[JTRUCKJMC]

You typically have to heat treat Ti, after welding, in a vacum furnace that is filled with an inert gas. Many Ti's are hot formed only and will otherwise crack
if not bent with the grain direction of the material. Ti must be welded to spec and with an inert environment, if not, you can have one hell of a fire ( like a white flare, that does not go out easily). The amount of equipment, time and effort will put this out of most peoples budget and reach. Good luck.

[Greg_Canada]

Got a Heli-Arc welder?
One thing i may suggest would be to talk to litespeed or merlin... they are companies that make titanium mountain bikes... if you want to know about stresses... dont think they could help you with the heat part of it tho...

[traindriver]

see if you can find a russian aircraft engineer. they used lots of Ti in their aircraft and lots of welds. verses rivets, bolts, and mechanical joints like the western aircraft designers. reason being is that the russians didnt have much aluminum avalible to them but had Ti coming out of their asses, they have the largest deposits of ti in the world.

[XtremeJ]

Great info everyone, many thanks.

We would be saving an additional 8 lbs over the current setup. Stock class so we are VERY limited in what we can do, exhaust cat back is free though. We spend almost $2K/set of wheels to save 4 lbs each. One of the car owners reckons he would pay up to one thousand dollars to save those 8lbs.

posts in this thread reinforce what I thought, apart from the expense the preparation and welding enviroment may be beyond the budget for this.

How important would the post welding heat treatment be?, when the exhaust does not need any integral strength. We are talking about a 42" run with two bends, and the tube is supported in three places with hangers.

[DemoMike]

http://www.woolfaircraft.com/racing.htm

maybe these guys can pull some elbows for you...

[DusterRT]

I gotta ask... how much weight are you going to be saving.

Wouldn't it be easier (and more cost effective) to loose weight in other ways?

btw - off topic question why haven't midgets started driving race cars.

What he said..

..and probably because they can't see over the steering wheel and/or can't reach the pedals. :grinpimp:

Travis

[XtremeJ]

What he said..

..and probably because they can't see over the steering wheel and/or can't reach the pedals. :grinpimp:

Travis

I could probably lose 20 lbs that I seem to carry in the front of my shirt.

To address the concerns of hiring midgets to drive, many sanctioning bodies stiplulate a weight including the driver. Robby Gordon spent the summer complaining that Danica Patrick has a 100 lb advantage. The Indy Racing league weighs the cars, excluding the driver weight. That 100 lbs could work out to be almost 7% of total weight, a fairly significant amount.

Some other weight savings tricks.
- turn rotors down to minimum thickness, replace after each race
- machine brake pads down to 1/3 thickness
- lightweight wheels at $450 each
- replace bolts and fasteners with lightweight fasteners
- cars are zero option cars, as stripped as you can get.

Then there are the pushing-the-legal-limit tricks, I 'll save those for another day, another thread.

[Greg_Canada]

I think ex-lax the day before the race may help :flipoff2: or try the LA weightloss diet :flipoff2:

[DusterRT]

You could also replace a dual exhaust system with a large single, space permitting..figured I'd add something potentially useful to this. And a smaller high-flow cat will save weight, rules permitting.

Travis

[Travis Waldher]

what about:

can you replace the steering wheel with a carbon fiber one?

Lugstuds and all bolts - cut off any extra you don't absolutely need.

battery - smallest battery possible.

altenator - rewind one to put out minimum amps.

carbon fiber body panels?

or is stock class... truley stock class, and you can't change that kind of stuff?

[YME]

Random thought, but could you clamp / epoxy the joints and hangers instead of welding them and save yourself tons of money and headaches? The money you save could be used elsewhere to save more weight.

[Captain Ron]

Grant, it's doable. I've done some pretty complex delivery mainifolds for areospace apps.

Sleeve the cat joint, you won't be able to sucessfully weld it to 321, 316 or 308 anyways. It'll be the place where the Ti cracks even sleeved. Eliminate any other possible welding.

Use CP, .016 wall looks pretty sexy... One of my local suppliers (http://www.twmetals.com/products/ProductFinder.aspx?sp=1&metal=T&alloy=CP&shape=TR&dimensions=Size1=2.5).

Anneal it first.

Watch your inside radius. Mandrel bending may be your only option, regardless, and then of course anyone who has done this will tell you about how Ti galls like nothing else. It's a real tooling eater.

Carefull heating may be required.

Proof the bends on 321 DMS. If you can do it with the 321, chances are it'll come out in CP. :grinpimp:

DO NOT USE 3AL.

--ron

[Brutpwr]

We sell tons of titanium exhausts at the bike shop I work at. Even on the dirtbikes they seem reliable. Myself if I were using it I would just buy the mandral bends in steel and flare them to fit over the titanium straight sections and clamp them together with 3/8" minimum Heavy duty exhaust U-bolts to save on welding /cracking hassles.

Jason :)

[Gozuki]

Why not just cut it off after the cat? :confused:

[XtremeJ]

what about:

can you replace the steering wheel with a carbon fiber one?

Lugstuds and all bolts - cut off any extra you don't absolutely need.

battery - smallest battery possible.

altenator - rewind one to put out minimum amps.

carbon fiber body panels?

or is stock class... truley stock class, and you can't change that kind of stuff?

We are in a stock class so most of the above would not be legal.

Steering wheels - must be OEM if they have airbags

Lugbolts - done

Battery - we run the smallest allowed.

Alternator - rewinding the alternator would be in the grey area of the rules. I have heard of certain competitors machining the inside of the alternator and starter casings to remove weight.

Carbon or replacement body panels - not legal.

[cbrogers]

Why not look into making your exhaust out of really thin Stainless.

You can get it in some pretty thin wall thickness, and oyu can get pre bent mandrel bends. For the ammount of length we are talking from the Cat back I cannot see it being that much difference.

We have a Busch North car which is basically and old winston Cup car and the stainless exhaust tubes are really light. And then you can just do regular TIG welding on it. Not have to worry about full argon purging our post treating the welds.

Carl

[KYcrawler]

why not use aluminum ? cheap easy to bend and easy to weld

mounting may be tricky as well as radiant heat