Stainless steel header hardware - cons?

[NY Twin Turbo]

It shouldn't be complicated. I'm an outlier. Plus work has been boring lately.

One lap of NCM has three 1500'+ WOT sections. That's three drag runs per lap, with just 15-20 seconds of part throttle in between each WOT blast. For twenty minutes. Steel hardware would last three sessions of that, and on the fourth would release and blow the gasket.

So steel is going to work for almost everybody here if they're just toodling around. They will eventually cycle out, but it'll take years. I had the same turbo flange studs and nuts on mine from 1987 until I replaced the turbocharger in 2012. That set lasted until my second event last year. Then I went through a set every event until I put the Inconel in it.

True. This type of racing is much less forgiving than most of our street car/weekend warriors. However, I do wonder how so many others have had troubles with this sort of thing. Loose nuts and studs, loose bolts, corrosion, blown out exhaust gaskets..........etc.

I'm no mechanic. And I never thought to ask if there was a special system for bolting this stuff up. And although my ride doesn't see a lot of track use anymore, it's still driven often and spirited. Maybe I'm lucky.

Maybe being a little more conscientious and observant could eliminate some of these issues? Are surfaces flat? Are you using enough anti-seize? Are the fasteners too tight? Too loose? Are the threads stripped?

 

[Turbo6inKY]

Maybe being a little more conscientious and observant could eliminate some of these issues? Are surfaces flat? Are you using enough anti-seize? Are the fasteners too tight? Too loose? Are the threads stripped?

This is key.

Fastener torque is a second order calculation away from clamping force. Which means small differences in fastener torque have huge impacts on clamp load. I know you know that. Just including for people reading this that aren't you.

Focusing on the turbo flange nuts: Those bastards are hard to reach. You can't get a conventional 3/8" or 1/2" drive torque wrench on them without a crows foot. There's just not enough space. Maybe you could get onto them with a 1/4" drive torque wrench, but how many of the 1/4" models will register 30-35 ft-lb? And what kind of Popeye forearms do you have to put 30 ft-lbs on a fastener with a 6" ratchet and maybe 10 degrees of swing?

How many of us have a set of crows feet and have properly torqued those fasteners? I'll wager the ones that have don't have so many issues with the gaskets blowing out. This is an area where those of us that have a quality shop maintain the cars have really good results while the shadetree guy is frustrated.

 

[Jerryl]

I don't drive my car much and certainly not WOT for mimutes at a time. Having said that, I do torque my iron studs/nuts junk and haven't seen any issues. Yeah, it's a pain but if you want it done correctly . . . Lol. My header surface was bowed a few years ago but a hand file took care of that.

Now, clearly the picture illustrates there is/was a clamping issue and glad to hear it was resolved.

I have to believe however that the average user has no issues with the GM spec'd hardware. If clampimg force was was a widely known issue, it would be mentioned more often.

Some of the heavy hitters change the turbos often enough, it probably never becomes an issue?

 

[dank GN]

Trackspeed:

Trackspeed Inconel Stud Kit

Don't allow the failure of an inadequate $2 stud to ruin your next track day. Eliminate turbocharger fastener failure with Trackspeed Engineering's Inconel stud kit. M8x1.25 and M10x1.50 applications are available for Garrett and Mazdaspeed turbochargers. We also have a specific M8x1.25 stud...

www.trackspeedengineering.com

They're a Turbo Miata shop, but they sell a Inconel stud kit for Garret housings. The M10x1.5 kit fits the three bolt garret housing most of us have.

Prior to putting this in, I'd burn through the turbo flange gasket at every event. After installing this, I have four track weekends on it and it's still sealed. And the Inconel doesn't corrode or gall, so pop the locks off the nuts and it comes right apart.

I’m i the only one who noticed the price for 4 bolts ? $150 to get your turbo to seal is pretty high imo . You can buy some regular studs with the locking Oblong nuts the torque wrench and the crows foot to properly torque them down for the price of those 4 fasteners. I have had great luck with a plan copper gasket I got from eBay . He can make a 3 bolt gasket aswell as different thickness.

 

[Turbo6inKY]

I’m i the only one who noticed the price for 4 bolts ? $150 to get your turbo to seal is pretty high imo . You can buy some regular studs with the locking Oblong nuts the torque wrench and the crows foot to properly torque them down for the price of those 4 fasteners. I have had great luck with a plan copper gasket I got from eBay . He can make a 3 bolt gasket aswell as different thickness.

Inconel is expensive. It's hard to make, and once you've created some, it's incredibly tough to machine. So the whole part is an order of magnitude more expensive to make than steel. Before I bought that set, I priced out getting studs made. They were $30 each, minimum quantity of ten. I could get it down to $20 a stud if I ordered a thousand of them. This stuff is why jet engines cost $25M each. All their guts in the high temperature areas are made of Inconel.

The thing is, for me, gasket material and lock nut type is irrelevant. When steel fasteners get hot enough, they release their clamping force, and then they start backing out. That point is far below the melt point. Once you've heated a fastener to the point where it releases, tightening it won't do any good. It's like a torque-to-yield faster at that point. It never clamps right again. So you have to replace them. At $1.50 each for quality steel studs plus a $12 gasket, you're at ~$15 each time. Plus the frustration of trying to replace a gasket on a hot turbo in between sessions at a track (or just packing up and going home). I went through that four times last year, so right there is $60 gone. It adds up.

The Inconel doesn't release until it's just about ready to fail, and that's at a point where the housing would have already melted off the car into a puddle on the ground. I inspect them after every event, and they haven't moved. For what I'm doing, it was well worth the expense. For almost everybody else? Probably overkill.

 

[earlbrown]

I’m i the only one who noticed the price for 4 bolts ? $150 to get your turbo to seal is pretty high imo .

It's expensive as hell.... BUT, if nothing below them will work, that's the price you have to pay to solve the problem.


It's like my old school huge ATR rear sway bar. I spit out two bolts that came with it in less than a week. Ended up with two rusty stockers, and two ATRs with the last thread flattend out. Damn thing squeaked and rattled to tell me to snug them back down more than once a month. Tried plastic nylock nuts and those kept the bolts from falling out after they backed off.

After trying for years, I make a pretty sweet fine thread aircraft bolt kit (internal lock washer, flanged head serrated nut, fine threads, slightly larger OD shank,etc....). Pretty hi-dollar parts. Put them on my eBay store in the bolt kit section for $50 (expensive as hell for ''only 4 bolts nuts and washers") and haven't sold one kit to date.


The only kit that's in use s on the back of my GN. ....and I haven't had to snug them up since the day I installed them.