Sorta, the Dirko HT came in only today. I will use that next time or source a Nissan T25 gasket. Audi forums shout that exhaust leak will cause loosening. So the flanges must be flat, gasket, Dirko HT, no leaks, Resbond and win. I hope...

 

I actually think the studs are just stretching. When I first had that top brace built, there was a single stainless-steel bolt and nut holding it together. I tightened it up, safety wired it, and it was tight. 2 track sessions later and I can spin the bolt/nut. I think the cast iron expansion is just stretching the hardware.

Does anyone make cast iron hardware?

edit: The more I think about this, the more sense it makes. Every time I take a setup that's been behaving on the street to a track day, it's perfect for a single session, since the studs have stretched and expanded but they aren't actually loose. Then the car cools fully, the studs contract, but not to their original length. The hardware is all loose then. Then I take it back out for the 2nd session and **** is falling off.

 

If it really is due to heat expansion, then maby the solution is making the studs a larger thermal mass, or reducing the temps around the manifold/turbo area.

Though I think side mount turbos have a natural tension to them, especially on track.

 

If it's really a temp expansion issue, you could also go with something like A286 Super Alloy caphead bolts.


McMaster-Carr

http://www.metalsuppliersonline.com/...etals/2090.asp

 

So, Inconel it is then...? It's used in Formula One exhaust systems so if it doesn't work for us we have a major engineering error in BEGI/FM cast manifolds.
Inconel - Wikipedia, the free encyclopedia

Inconel 751: Increased aluminum content for improved rupture strength in the 1600 F range
http://www.specialmetals.com/documen...lloy%20751.pdf

BTW, the Resbond does sort of swell up when cured, so it should do pretty well as a thread sealant.

 

I doubt you can find Inconel 751 bolts cheaper than $100 a piece at low volume.

 

I want studs, not bolts. But still, if I fix this voor $400 it is still alot cheaper than v-bands.

 

A286 can be found for $17 a piece, similar properties, used widely in aerospace turbines, and readily available.


High Temp Metals 800-500-2141 - Alloy A286 Technical Information



Looks like air power systems use A286 studs and copper lock nuts in their turbo kits.

 

Sav,

Did you re-torque your nuts a few times before safety-wiring them and hitting the track?

 

uh, look at the stress curve for those Spookyfish, you're into the plastic range at 1300 degrees, so you won't be good to 1600 degrees. I have no idea if your EGT's are that high though.

 

If your fastners are at 1300* F then you're going to be experiencing alot of failures in alot of other areas. Your inlet EGT shouldn't be the same as your outlet EGT, and your fastners shouldn't be anywhere near the inlet EGT.

Guessing the temp range that the fastners will need to live in, is like tuning without a wideband. Why doesn't someone that's having problems throw a thermocouple on the studs and tell us exactly how hot their **** really is?

 

I'm putting an EGT on each cylinder, but nothing for the fasteners. I'm also planning to add water which will most likely cut EGT dramatically.

Does anyone make 1000*+ temp "sticker" thingies like what we've used on calipers and radiators?

 

^^ Check with Omega.com since they will most likely have it. I am guessing it will probably be permanent change paint at that temperature level. It exists in formulations hot enough for brake rotors. Omega is not the cheapest source, but usually has a ton of good information and products for any given measurement/instrumentation technology.

 

Temperature Indicating Rotor Paint - RaceShopper.com

http://www.truechoice.com/prodinfo.asp?number=GB 1000

Though it's more like tuning with a narrow band. At least you'll know it's getting above 1000* or 1250* but there's no way to tell the difference between 1250* and 1600*.



Get this.

http://cgi.ebay.com/ws/eBayISAPI.dll...%3D4%26ps%3D10

Measure temps.

Profit.



Another thing to keep in mind, aluminium's melting point is 1220.58*F. Sure the EGT's will be higher, but if the fastners are getting over 1300* I expect you to start having problems with the valves and head.

 

Stage 8s dont hold up at Thunderhill @ 95* track temps either:
IMG_0519.jpg
IMG_0520.jpg

After looking at these pictures a few times I have noticed that the stud to the front of the car. Closest to us in the picture, is out a bit further than when i originally installed the studs. Also, note that the lower stud AND stage 8 locknut is missing. That fell off during the track event. Worked for 3 sessions, then fail.

I am guessing the stud actually backed out from vibration and eventually made the locknut fall off. This all happened in one session.

What next?

 

Did you re-torque them after a few street heat cycles after initial installation?

 

No, i cant fit a torque wrench on there. They were hand tight, as tight as i could possibly get them.

 

^^+1.

 

snowboarder,
Use a crow's foot.

If you guys are tightening nuts up make sure to do it when everything is cold or you'll insta-phale.

 

snow, the point is to retighten a few times after a few street heat cycles. Every time I re-install my turbo mani, I see the need to do this.