Technical Cinq Manifold and system

[Puntodan]

A few years back i used to help out at a place tha modded cinqs and sei's and they used to put on a group N manifold and system, Trofeu or soram something like that!

I have searched the net but can't find anything on them was wondering if they are still made and how much as I need a new exhaust so thought i might as well go the whole hog and replace the manifold as well to give it a bit more power.

Help!!

Dan

 

[custard]

well i know supersprint and janspeed do a manifold.one oother company as well IIRC

 

[arseofbox]

It was GSR.

I cant find any info on the Soram Grp N system anymore, and I dunno why GSR stopped selling them.

OMP still do a Group N system AFAIK. IIRC its about £200 manifold back (decat )

I have a Ragazzon Group N cat back system and its gorgeous..but not really loud. I dont think it really helps any massive power gains until very high engine speeds though, and its unfortunately out of production too nowadays.

 

[Puntodan]

Ideally I want a 4-2-1 manifold as that will help get the gasses out no end comapred to the standard job and the rest of the system I can make up after that! Don't really wanna pay a fortune for it though!

 

[Oldschool]

The group N system is much lighter than any other exhaust system. It has got quick release fittings, which are rather essential for the kind of racing they have been intended for.

Disadvantage on the group N system is that is hasn't got any stress release points. The Supersprint manifold is technically virtually identical but has got a knuckle joint, which releases the stress from the engine twisting under load. Too many of the manifolds were breaking.

Best system is still the Supersprint for the Centos.

 

[arseofbox]

Ah I see...I didnt know that.

Is there much scope for using aluminium tubing in place of steel? I know this would present issues for the cat and theres gonna be horrific galvanic corrosion in places...Only thinking as Im thinking of having a system made up with a replaceable cat section or sport cat to follow the same layout and box types as the Grp N.

The system I have has a knuckle built into the cetres section so is obviously a Grp N replica. Oh well.

 

[Luke M]

aluminium has the same strength as the steel but weighs alot less. u might need a slightly thicker guage though but i aint sure. the main difference between aluminium and steel is that aluminium has a MUCH lower melting point about 250 degrees IIRC, cant find my design book to find the exact value. so i dont know how the heat of the exhaust may affect this. if your pipes got hot and u hit a pot hole they may sheer off. however aluminium disipates heat alot quicker than steel.

i dont know much about manifolds but thats a bit of info on the physical properties of the materials if any help

 

[Oldschool]

Mild steel has got a lot of advantages over any other material used in exhaust design. The knuckle joint is the cure for many stress problems on the exhausts. But it mustn't be overtightened when spring loaded like the Supersprint.

Aluminium is unsuitable for this sort of design.

 

[arseofbox]

aluminium has the same strength as the steel but weighs alot less.

Nope. Young's Modulus -the measure of tensile strength (E),Carbon Steel ~= 200GNm-2, Aluminium ~=70GNm-2.

Thats less than half! This is only of interest as Id think the manifold-cat joint is under a time varying tensile-compressive force, and thats the part most likely to fail in this loading. The manifold would probably be quite likely to fail under creep though, due to the high temperatures, temp cycling and loading involved.

u might need a slightly thicker guage though but i aint sure.

Yeah. to achieve the same load using the idea Force = Load / Area, the Aluminium would need about twice the area of the steel to withstand the same purely tensile load.

the main difference between aluminium and steel is that aluminium has a MUCH lower melting point about 250 degrees IIRC

Yeah 250 deg C sounds about right. Aluminium's MP is about 1083 deg C, and the steel's will be dependant on the composition of the alloy, as for the likelyhood of shear failure, I dunno, but IIRC, Aluminium usually has less cycles to fatigue failure than a steel under the same loading.

Other thing to bear in mind from all this, is that these ideas are purely theory and may only partially reflect reality - the actual scenario will have a mixture of loading / strain effects, but only one will be predominant (it will be the critical case - and cause failure before any other mechanism does)

. Long and unintentionally bitchy I know..Sorry!