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Discussion Starter #1 (Edited)
I was asked to post this by a Lotus Forum member.

I have no affiliation.

Ed

http://www.thelotusforums.com/forums/topic/61738-alunox-321-ss-manifold-for-esprit-turbo-group-buy/



Alunox 321 SS Manifold for Esprit Turbo Group Buy
Started by MarkKassim, Dec 03 2013 12:54 PM


#1 Alunox 321 SS Manifold for Esprit Turbo Group Buy: post #1
Mark Kassim
LO

Posted 03 December 2013 - 12:54 PM
Another chance to buy the 321 Stainless Steel manifold upgrade from Alunox. This is our 3rd group buy and just to recap on the history of the product. It was developed by Alunox who are a well established engineering company that supply the motorsport industry with tailor made high end exhaust systems, made of exotic materials such as Inconel, titanium and 321 Stainless Steel etc. Alunox took on the job of redesigning the original cast manifold for the Esprit due to its failure rate. But also were able to offer uprated performance using their expertise in this area.

The manifold is constructed from 321 Stainless Steel, precision TIG welded in dedicated jigs giving a fracture proof construction. The flanges are laser cut out of Stainless Steel to give an accurate fit, the collector uses burns double slip joints to allow movement during the heat cycle whilst being supported by the pivoting brace mounted directly under the turbo.

Intro.jpg

The downpipes are all equal length mandrel bent tubes to maximise flow arranged to fit within the space available. Even at normal driving speeds the exhaust gas temperatures are typically 750 to 850 °C and greater during track use. The manifold has been proven to withstand all the temperatures and conditions produced by the Esprit. The manifold is also lighter than the original cast unit weighing only 6 Kg. All these attributes produce a durable high quality product with gains in both power and torque and lag reduction.
It has been dyno tested as seen in the video below on a highly modified Esprit running at 424 BHP and 409 lf.ft torque.




Further in-depth technical info on this can be found on Dave Changes thread
Exhaust manifold design test result.. - Induction/Turbo/Chargecooler/Manifold/Exhaust - The Lotus Forums

It has also been track tested and driven hard without fail. Look for feedback on the forum about performance gains.
The kit also includes all gaskets, stainless steel nuts and studs and brace. The turbo flange can be changed to accommodate different turbos, as can the collector be made to order. These adjustments are at extra cost and can be discussed with Leon at Alunox.
The manifold comes with 2 year warrantee, this does not cover fitting and shipping.

The normal one off price is £1150 + VAT.
The group buy price £1000 + VAT + Shipping, for 10 off
I will put up shipping costs later

In addition to this there is also a stainless steel K nut option for the manifold head studs. This is an alternative to the Lotus locking tab washers. This option is about £35. I will post later if anybody's interested.
If you want to take advantage of this offer sign up below and I’ll add you to the list.
Thanks,
Mark
 

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I got one of these during the first group buy and have had on my car now for approaching a year.

Experience thus far...
Zero issues with quality, very nice welds, etc.
Definitely reduces turbo lag

Shop who installed for me was supposed to dyno my car before and after install but forgot so dont have hard figures though can say everyone who has driven it and had either driven my car prior or another same model Esprit said the same thing: Spool up much improved.

Overall I am very, VERY pleased with it. Plus it looks cool when you show it to people!
 

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Cal H
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Alunox does have a good reputation. The material and construction looks good. A couple of the local club members have bought them on past buys. The owner of my former car is in no hurry to put it on as it is still sitting in his garage. I am still waiting for long term durability reports before I spend that sort of money (and one of the OEM manifolds I have does not have a crack), so I will wait. I have seen several versions of the tubular manifolds produced by others and their reported failures after various periods of time. The OEM manifolds do crack and the later improved cast manifolds while resistant still crack but when they fail it is after many years and upwards of 40K miles. I can live with failure at 40K+ miles and 10+ years. Due to my budgetary constraints I must let others be the pioneers in this area and rely on them to report back to us on the durability issues. Since they issue a 2 year warranty Alunox must be confident that it will at least last that long. For the average owner that is not much miles for an occasional use Esprit.
I know there are a few fence sitters like me paying close attention to Alunox manifolds currently in use.
 

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For what it is worth I have the Al B stainless steel header which was also ceramic coated (exterior only). I have about 7k miles on it. Very happy. Coating has held up very well and so has the header itself. Noticeable improvement on turbo spool and significantly lighter than the stock cast header. As I recall the group price was about $600. It was a one-off project unfortunately.
 

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Cal H
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For what it is worth I have the Al B stainless steel header which was also ceramic coated (exterior only). I have about 7k miles on it. Very happy. Coating has held up very well and so has the header itself. Noticeable improvement on turbo spool and significantly lighter than the stock cast header. As I recall the group price was about $600. It was a one-off project unfortunately.
I remember that manifold. It was during the time frame when several people were trying to make one and many failed. I think many used inferior stainless and most never lasted too long. Alunox is way too expensive for me when it is all said and done i think the USA delivered price is near or might even exceed 2K. I would say a lot of the orders are from the USA and the future hope is someone would just shop the item from a USA supplier. There has to be a shop in the USA that can make a similar manifold. There is huge premium for items from the UK. I really don't understand why it appears less expensive for item of origin from the rest of Europe as opposed to items from the UK
 

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I agree - I would like to see more U.S. custom shops creating Lotus replacement parts. I know that Al B. put in a hell of a lot of work to get this done - to the extent he said "never again". I was very pleased to see our experience with fuel tanks led Boyd Welding to offer a U.S. made aluminum Esprit tank for a reasonable price. It would be great to see something like that happen with a header.

By the way here is a picture of the Al B header installed on my engine.... I always thought is was quite an attractive looking piece as well! And I will always be grateful to Al for carrying this project out.
 

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WOW! That is nice Tom!
 

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That picture was taken during the rebuild but I was waiting for some shims to finish installing the exhaust cam tower - that's why it's "missing in the picture!

Here is a picture with the engine completed just prior to installing it back in my car. I've put about 7k miles on it since completing the renovation of the car and it has run wonderfully. I had a chance to take it up to the Carolinas (from Florida) this past fall for a long weekend and it was one of the most delightful drives I have ever experienced.
 

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