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Alunox 321 SS Manifold for Esprit Turbo Group Buy


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Hi Guys , an update from Alunox. All the manifolds are now complete and will be going out next week. Just waiting for the new brace.

The new brace acts more from the centre of the turbo making fitting more straight forward.

This is a mock up and the final article will be complete next week.

The new brace will be sent to all existing customers who have bought a manifold.

Mark

post-13397-0-65961400-1408049789.jpg

post-13397-0-57786800-1408049900.jpg

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  • 2 weeks later...

I've put a post up on the other Alunox manifold thread, I kinda think I need to cross post it here as the info I feel is very important...

Contrary to (maybe) contrary belief, I'm not just trying to stir up trouble, that really isn't the case...

Edited by Simon350S

Chunky Lover

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The manifold was finished about 6 weeks ago. Sent it to zircotec for coating And they said 10 working days. I called them after 10 working days and they said they were very busy and it was going to be 25 working days. It got back to the shop yesterday so hoping to get a call soon to collect. The shop have been really cool about it, they've stored the car the entire time with no complaints even though the delay was in no way their fault.

Hopefully the Zircotec coating was worth the wait.

I'll put up a thread about the manifold after I've got it back.

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Fab :D thanks for posting.

I'm keen to see how the turbo mounting issue has been addressed by them, if indeed it has at all.

The best turbo support bracket I can recall seeing was the one where the bracket was a continuation of the manifold to head mounting flange.

Not sure how that one frared long term though.

Chunky Lover

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Yeah, I'll put up some pics.

Why is cracking such a big issue on these cars? It's not a huge turbo and there are plenty of turbo 4 pots out there that don't seem to have this issue as badly. Is it the turbos position at the end of the head adding greater leverage?

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Turbos just aren't meant to be supported by tubular exhausts, simple as that. It's not just the static weight that needs to be considered, it's the forces acting upon it during real life driving. Potholes, speed bumps, heavy cornering and braking...

Most cars I've seen from the factory have cast manifolds which work perfectly well for bolting a turbo to as they are thick, heavy, lumps of metal...

The cracking of the original manifolds seems to be down to a combination of heating cooling cycles stressing the casting, heavy water splashes when driving through standing water and many other factors. Is it the SWLC ones that had elongated bolt holes in the manifold to head flange or the original as well? Can't remember.

Over tightening of the exhaust manifold to the head can reduce the ability for the manifold to expand and again adding forces to stress crack the casting...

Edited by Simon350S

Chunky Lover

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  • Gold FFM

I was told it was because of the thermal shock of water splashing on the glowing manifold when driving through a puddle. Not sure of the validity of that though.

 

 

Edit: Simon was far more eloquent! 

Edited by Mysterae

Signature not working...

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Now we are getting there!

I'd like to see a 1 piece exhaust port 4 flange, to turbo flange as I'm still not sure about the 'box section?' That's welded on just under the turbo. Another week spot potentially.

1 whole chunky piece of metal!

How is it holding out?

I'm surprised there's been no response to my post above by those in contact with Alunox as I seriously think this needs to be properly addressed and pretty pronto too!

Chunky Lover

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Hi Guys, I’ve just arrived back after being on holiday in Wales, no internet connection. I can see we are going over old ground again in terms of the design of the Alunox Manifold.

I can see the example shown is a tubular copy of the original Lotus log style manifold. The original suffered from cracking in the elbow region since this is where the greatest expansion occurs. There were other issues with the bracing running from the forth port to the Turbo flange, it tended to pull the forth port away from the head causing a leak exactly between the top and the lower right hand Bolts. It also contributed to the stress in the elbow as the turbo flange was unable to move freely during the heat/cool cycle.

I had two cast manifolds and the problem persisted repeating about every two years. I would remove the manifold then take it to be milled flat and replace with new Lotus gaskets each time. After speaking with Pete from PNM, when I mentioned I had a leak at the head, he already knew which port before I told him as he has seen it before.

I was getting tired of this and approached Alunox for a solution pointing out all the problems. The resulting new design was developed with the following properties

  • Choice of material – 321 Stainless Steel as it is fracture resistant at very high temperatures and already proven in race car turbo applications.
  • Elbow expansion – Slip joint to allow for movement during the heat/cool cycle.
  • Flow layout and design – Four Equal length primaries feeding into dual collector giving less turbo lag, better throttle response and enhanced power/torque curve.

The dyno results showed a 64 lb/ft increase in torque over the log layout on Dave Changes car. I have ran one now for 4 years with no cracks.

The weight of the turbo is suspended by the manifold the brace acting as a safety net against shock loading. The manifold is constructed from 1.6mm tube but this varies to 2.0 mm at the first 50 mm of tube coming from the cylinder head flanges. The load bearing strength comes from the collective structure of the tubes together meeting at the slip joint.

The point that has to be made here is that the manifold has to be able to move during its expansion and contraction. If we restrict movement by over-elaborate designs on bracing we may distort the manifold.

Alunox have recognised that the brace needed a second look at after the reported failures. There are few factors in this concerning the amount of expansion in the elbow.

  • Pivot position not giving sufficient radial movement to the centre of the turbo flange.
  • Lower rose joint being too close to the collector causing it to corrode/ Seize and restricting movement.
  • Better fitting instructions required.

The lower new brace design will correct the above problems and will be issued to everyone free of charge. It has taken some time as it isn’t just a case of bending a few pieces of metal and sending them out .The brackets are being laser cut and Alunox are waiting them to come in.

To somehow come in last minute and say the whole design is flawed is a bit strong, tweaking might be a better word. Manufactures often evolve their products and at least Alunox stand by theirs.

For those of you reading this for the first time, I may need to point out Dave Changes dyno tested a log design very similar to one shown here back to back with the Alunox one at his own cost and provided the forum with the data. Dave has also been in the trade and has one of the most powerful cars on the forum and so is recognised by many as a technical authority on the Esprit.

I will update the forum with news on the brace

Mark K

 

 

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I know when I had mine made I had to have it dressed a couple of times before the fit was right. Been on almost 3 years now and no issues so far and can be fitted and taken off without touching the engine mount as I had to do this each time it was dressed. These look a good product and a bit of development will be required so people should not loose faith.

All the best

It's Oogies turn to boogie

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  • Gold FFM

Meanwhile, can Alunox please send out the manifolds?  Things are getting desperate now, and I can retrofit the brace later.

British Fart to Florida, Nude to New York, Dunce to Denmark, Numpty to Newfoundland.  And Shitfaced Silly Sod to Sweden.

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