They're not using them anymore, back to a 4-bolt.

 

With Inconel studs that are not stretching?

God this **** is annoying, right when I am ready to spend money we find that what had previously worked well was starting to not work.

 

What are those square flats on the top of the manifold for?

 

Triangle is:

1. Front driver's engine mount lift-eye bolt <or> frontmost upper exhaust manifold stud. This link will be in compression.
2. Rearmost upper exhaust manifold stud <or> cas bolt <or> transmission housing bolt. This link will be in compression.
3. "crossover" bar mounted to intake manifold. A turnbuckle is used to adjust tension. This link will be in tension.

Not sure how securing the assembly to your turbo-to-manifold connection is going to help with your CHRA to Turbine housing bolts. At least, those are the only bolts that I'm picturing you having problems with in my mind. I don't know how any sort of crane assembly on the turbine side would help. You said you wanted to mount to the compressor housing, which makes sense to me as far as solving your problem. Mounting to the turbine housing isn't going to help that area - it seems now you're dealing with vibration vs. the weight of the compressor/chra/intake plumbing instead of the weight of the entire turbocharger/exhaust system... Have I lost my mind?

 

I might be concerned about vibration weakening something at that point. I'm not sure how much the exhaust manifold flexes when it's hot. Front to back motion on those housing bolts might end poorly.

I would feel more confident if the bracket attached to four of the bolts to spread any load out over more of the turbo housing.

 

We've all lost our minds. I'm staying away from mounting to anything that holds the turbo on the car for the crane, I think that makes sense when considering torsion on stuff that get's hot. Mounting to the motor mount locations is not an option, the turbo is too close.

 

I agree with you, and this is why I looked to the compressor housing. Mounting here pushes the fulcrum point "further out" and away from heat, I think this is a good tactic to reduce vibration.

I'm not an engineer, but I've realized that all that heavy turbo stuff on the end of the manifold is a tuning fork essentially. It's easier to stop vibration my touching the end of the tuning fork rather than the middle. Draw a straight line through one of the manifold runners, vibration is occuring their. Now think of a sea-saw where the fulcrum point is the v-band at the maifold. Connecting the crane close to the turbine housing will do less to damp vibration than at the compressor housing.

Will someone who does math and engineering explain this for me, I feel like a troglodyte describing my uneducated thoughts.

 

Whoops, didn't mean engine mount bolt, meant enging lifting eye bolt. Will change in original post.

 

UGH, why did you have to post a pic of a 2.7?

 

It almost looks to me like you could fit a diving board type brace under neath that bolts to the block. I can see the bolt holes on the block in this picture that you could use:



The GTX came stock with this as you can sorta see in this picture I took while pulling the engine. I can get a better one later if need be.



I believe bundy has been running this sort of brace for a long time and it seems to work for him.

 

My old turbo Miata had a setup just like what you see above -- a heim joint bolted to a modified turbine clamp plate. The other end of the heim joint attached to a 'crane' -- a piece of barstock about 7/16" dia that was threaded at one end and welded to the the manifold head flange at the other. The reason for picking it up at the turbine rather than compressor is to get closer to the turbo's CG.

The clamp plate cracked off twice. The manifold developed cracks in several places. Not from poor manufacture, but because of vibration. BPs are thrashy, violent engines. My (16ga tube equal length 321) manifold would resonate visibly and audibly at ~2900 rpm. This is what cracked everything to hell.

A heimjoint crane will help support the mass of the turbo while letting the manifold grow and move around, and this will help the manifold live, but it will do nothing to increase the turbo/manifold's natural frequency (i.e. stiffen it). Too many DOF.

To stiffen the system you need a rigid brace between turbo and block. Stock MSMs have one. All Evos have one. I eventually made one too and it solved my resonance problem. The rigid brace posits that allowing movement via thermal expansion is secondary to increasing the natural frequency of the turbo/manifold.

So the style of support depends on the problem you're trying to resolve.

 

How do I make a rigid brace that permits expansion and contraction of the manifold?

 

Maybe we need to be thinking less "turbo brace" and more "stock intake manifold brace" - one is a generic design, the other was designed by engineers that make a lot of money to make things not fail specifically on this engine.

 

You running ATI engine damper?

 

Of course not, I didn't have room for one until a few weeks ago due to the swaybar brace. I'm not certain this is the fix either, nor do I have $600 and want to pull the motor to install it.

 

Make it less rigid in one plane like the stock MSM one.

 

depends on which direction it's rigid in. think leaf spring I guess.

 

Aryamehr:

 

Think about a diving board like I mentioned. Its how mazda does it stock.

 

Are there any thoughts on the movement of my manifold as it expands and contracts? I'm not really sure where to go here, but I'm well on my way. I suppose I could attach it to a water line and use the same "plane specific" orientation as Mazda did.