manfucturing headers for M20 design help

[mrLEE30]

went to one of our local garage/ exhaust repair shops the other day and they hand make headers, they were fitting some on my mates GMC and for him they worked really well.

These lads cut and bent and weld mild steel (i think??) and make exhausts to order, including headers, mid section, silencers the whole nine yards, they will also copy anything, they can do stainless too but pricey!!

So what i want is pictures of headers for an M20, and if possible could someone tell me the best header length (i.e from head to collector) so i can try to have them knock some up for me. also what is best pipe diameter, the pic below to me looks like 2 inch....anyone?

and the last question that no doubt will get the bigger engine boys repliying with why bother, get a bigger engine etc etc.. i will have a go at putting these on my M20B20, but would i really need a chip and 2.5 TB to get any real difference? not looking for silly power gains to go drag racing just exploring cheap ways of getting my cab to put put along a bit happier!!

also help me on this and i may be able to get more made for the zoners, looking at around 200 quid for headers and mid-section lads!!!

i have this one...

[M5pilot]

So your going to Copy other people's designs?

The manifold above cost alot in terms of development.

I would see it as very unethical to go round copying the design.

The above manifold is probably the best design in the world as far as manifold currently in production. The materials cost is quite large as you can see alot of stainless steel is used.

BTB designed the headers for 2.7 engines and optimised them as far as bore size and header length is concerned within the confines of the space available on a RHD car.

People don;t mind paying for the above manifold as the workmanship and quality is simply brilliant.

Sal

[Simon13]

heres another to copy if u can!

Racing Dynamics






Magnex



hth

[mrLEE30]

I would see it as very unethical to go round copying the design.

yes i feel the same but nothing is available here, and if i have the facilities to manufacture a pipe then why not? difference is in uk it would cost as much to fabricate as to buy. further i was asking for any advice as to the lengths of pipes so i could have a go at designing my own, and hence why i am asking for samples to give me ideas.

my intentions were not to mass produce or even sell them commercially as i have no export / import licence just fancied having a play with my exhaust and if i can come up with a design that works then we would see if i could make a few available to zoners, they actually have a jig for one already i found out today, which looks similar to the Magnex one above.

so again i ask anyone who may know about these things.... what sort of length and bore should i be looking at?

mrlee

[Simon13]

the primarys on mine are 40mm OD, length not sure they look about 500mm

[mrLEE30]

cheers, will check his jig and see what they have already, otherwise may need to start from scratch!!

just need to find some free time now!!

mlree

[Julian_Jules]

keep us posted.....

[mrLEE30]

all on holiday here for Ramadan Eid, will look more in depth about this in November. It is now cabby season and my car shall not be off the road for five mins at the moment... 28C in the evening

[old_skool]

28C in the evening

Hmm. it's wet and rainy here and the leaves are on their way off the trees. Lucky bug&%r