QUESTION
There is an opportunity to buy one of these Aluminox manifolds from a previous UK lotus forum group buy, to replace my factory cast manifold. I haven't really had any issues with the stock cast piece like a lot of people have seemed to but I was wondering what your opinion was on this stainless steel item on offer?
B.C. - Sydney, New South Wales
ANSWER
Unfortunately I have no experience of building fabricated manifolds from 321 stainless steel so its difficult to comment.
However I have seen fabricated manifolds made from 304 and have failed prematurely.
Fabricating a manifold for any turbo-charged Esprit that is going to provide lasting results is going to be difficult.
When you analyse the design requirements it high-lights the problems.
The manifold material and construction need to meet the following conditions -
1) Withstand elevated temperatures in excess of 400 degrees Centigrade
2) Withstand temperature cycling
3) Withstand corrosive exhaust gasses
4) Be fatigue resistant
5) Be resistant to oxidisation
The Turbo-charged Esprit manifold has several problems where it has to be very robust/rigid to support the entire exhaust system right the way back to the muffler
The rear muffler is the first point at which the exhaust system is supported.
The exhaust manifold needs to be rigid to provide a fixed mounting platform for the turbo-charger.
This is important as the turbo-charger needs to mate seamlessly to both the induction system as well as the exhaust.
It is worth noting the manifold design being offered has a lack of gussets and minimal support with just one strut.
To ensure the fabricated exhaust manifold has absolutely no movement, there needs to be a second strut to triangulate the fixing points.
Whilst this manifold looks to be well presented only time will tell if it has longevity and offers value for money.
If you are going to invest money in a fabricated manifold then a better option would be to have it made in a superior alloy such as Inconel.
321 stainless steel is great for larger components that will be subjected to less fatigue or stress.
As a matter of interest, Lotus Marques has specified 321 stainless steel to re-manufacture new Esprit waste-gates - see attached drawing
From experience it would be wise to wait, watch and listen until such time you do need to purchase a replacement manifold.
Copyright © 2014 Lotus Marques
There is an opportunity to buy one of these Aluminox manifolds from a previous UK lotus forum group buy, to replace my factory cast manifold. I haven't really had any issues with the stock cast piece like a lot of people have seemed to but I was wondering what your opinion was on this stainless steel item on offer?
B.C. - Sydney, New South Wales
ANSWER
Unfortunately I have no experience of building fabricated manifolds from 321 stainless steel so its difficult to comment.
However I have seen fabricated manifolds made from 304 and have failed prematurely.
Fabricating a manifold for any turbo-charged Esprit that is going to provide lasting results is going to be difficult.
When you analyse the design requirements it high-lights the problems.
The manifold material and construction need to meet the following conditions -
1) Withstand elevated temperatures in excess of 400 degrees Centigrade
2) Withstand temperature cycling
3) Withstand corrosive exhaust gasses
4) Be fatigue resistant
5) Be resistant to oxidisation
The Turbo-charged Esprit manifold has several problems where it has to be very robust/rigid to support the entire exhaust system right the way back to the muffler
The rear muffler is the first point at which the exhaust system is supported.
The exhaust manifold needs to be rigid to provide a fixed mounting platform for the turbo-charger.
This is important as the turbo-charger needs to mate seamlessly to both the induction system as well as the exhaust.
It is worth noting the manifold design being offered has a lack of gussets and minimal support with just one strut.
To ensure the fabricated exhaust manifold has absolutely no movement, there needs to be a second strut to triangulate the fixing points.
Whilst this manifold looks to be well presented only time will tell if it has longevity and offers value for money.
If you are going to invest money in a fabricated manifold then a better option would be to have it made in a superior alloy such as Inconel.
321 stainless steel is great for larger components that will be subjected to less fatigue or stress.
As a matter of interest, Lotus Marques has specified 321 stainless steel to re-manufacture new Esprit waste-gates - see attached drawing
From experience it would be wise to wait, watch and listen until such time you do need to purchase a replacement manifold.
Copyright © 2014 Lotus Marques
