Mi16 Exhaust In 205

[stefan 4]

Does anyone have any pics or/and a description how to modify a mi16 exhaust manifold to fit into the 205 without bashing the bulkhead?

I can’t decide which way to go.

If anyone’s done it I would sure appreciate the info.

Edited July 13, 2010 by stefan

[welshpug 1,629]

chop+ bend then tack, trial fit and adjust if required then weld up. pretty simple really!

[stefan 4]

where do I chop, what do I bend?

[welshpug 1,629]

both the manifold to make it fit in the engine bay without hitting the bulkhead, then once done do the same to the downpipe.

 

or you could source a direct fit 4-2-1 manifold from the likes of pugracing (miles)

[Baz 421]

This has been covered many times, have you tried the search function as there'll be lots of info & pics for you!

[stefan 4]

Yes, but my dilema is where to cut the manifold.

If I cut all 8 pipes at the flange, bend it down, when I weld it back up it will distort the flange, and I’m not getting the clearance to the left anyway,

Now I’m considering cutting it at the end where the pipes meet, but the splitter is inside…

And then modifying the downpipe

[stefan 4]

This has been covered many times, have you tried the search function as there'll be lots of info & pics for you!

 

Yes I've tried the search but couldn't find anything, can you direct me?

[jimistdt 1]

Try these Stefan;

 

http://forum.205gtidrivers.com/index.php?a...+mani*&st=0

[hatemgti 4]

You can just buy Mi16 Exhaust Wedge Plate.

[stefan 4]

Try these Stefan;

 

http://forum.205gtidrivers.com/index.php?a...+mani*&st=0

 

read those, usefull info, but again nothing concrete about modifying the manifold and downpipe.

It's a shame because this is a 1on1 basic mod, but it seems that it's not properly covered.

At least I can't find anything.

There should be a guide done step by step with pics.

If I manage to get it wrigt, I'l put it up.

[Simes 248 2 Cars]

read those, usefull info, but again nothing concrete about modifying the manifold and downpipe.

It's a shame because this is a 1on1 basic mod, but it seems that it's not properly covered.

At least I can't find anything.

There should be a guide done step by step with pics.

If I manage to get it wrigt, I'l put it up.

 

Why?!

Some folk will make you one and charge - they had to find out how to do it.

If it's a basic job as you say then you could offer up the manifold, then cut and weld then it is straightforward job.

Otherwise you can buy a wedge or do like me and buy a 4-2-1 maifold.

 

Edited July 13, 2010 by Simes

[stefan 4]

Why?!

Some folk will make you one and charge - they had to find out how to do it.

If it's a basic job as you say then you could offer up the manifold, then cut and weld then it is straightforward job.

Otherwise you can buy a wedge or do like me and buy a 4-2-1 maifold.

 

 

Because I don't mind sharing knowledge, rather then selling it.

It's not a basic job, it's a basic mod-putting the mi16 into the 205 (isn't it?!), and the ex manifold is one of main things that need modifying.

Not everyone goes out and buy bolt up's at the first sign of trouble

Edited July 13, 2010 by stefan

[luggy 13]

Not everyone goes out and buy bolt up's at the first sign of trouble

 

You do if you dont have the means to hand to resolve the problem.

Anyway couple of handy links

 

http://forum.205gtidrivers.com/index.php?s...angle&st=10

 

http://forum.205gtidrivers.com/index.php?s...=manifold+angle

[blessed6383 0]

You can just buy Mi16 Exhaust Wedge Plate.

 

the problem with the wedge plate/angle adjuster is that the bolts wont sit flush and some people have problems with getting a good seal against the head

[Simes 248 2 Cars]

It's not a basic job, it's a basic mod-putting the mi16 into the 205 (isn't it?!), and the ex manifold is one of main things that need modifying.

Not everyone goes out and buy bolt up's at the first sign of trouble

 

I didn't buy it because of the first sign of trouble - I bought a 4-2-1 because it was the better option.

[series111 21]

You do if you dont have the means to hand to resolve the problem.

Anyway couple of handy links

 

http://forum.205gtidrivers.com/index.php?s...angle&st=10

 

http://forum.205gtidrivers.com/index.php?s...=manifold+angle

 

When i done my exhaust i made some radiused washers and radiused the bottom of each bolt which are cap screws these now fit flush with the manifold giving a gas tight seal ....

[DrSarty 90 1 Cars]

And PeterT's Mi wedge kit (for using the Mi16 8-1 manifold) includes exactly the correct washers and bolts/studs to deal with the issue.

 

It's not like we haven't done this before, but it's not really a topic you can give a definite answer to, just like your 'ulitmate ITB and management' topic. After all it's only cutting partially through 8 tubes, tapping it down TO SUIT THE ANGLE YOU NEED (!!!), tacking it for a test fit and then re-welding it once any changes have been made.

 

The 205 is a strangely odd beast, and posting a topic which tells people to angle it 5deg down might mean some exhaust downpipes don't meet, and/or foul the bulkhead. It has to be done to suit your install, to ensure it works OK. Getting it wrong will make fitment difficult and may blow, which is horrible.

 

I will be doing mine soon, but I also have 2 reangled Mi manifolds, both of which are different.

 

When I actually cut, re-angle and re-weld some of mine, I will post some pics; but it's only going to be as described above, isn't rocket science and I wouldn't recommend anyone copies the angles or cuts too closely. It has to be done to suit your engine, car and exhaust combo.

 

And as Simes says, a 4-2-1 generally produces better results, so it could be argued it's not worth the hassle, unless you don't want much more than 200bhp and are good at welding.

Edited July 13, 2010 by DrSarty

[stefan 4]

It's just a question of where to cut and weld, for me, Sarty, don't need exact angles and measurements, the fine touches, OF COURSE, have to be made at the sight.

If I cut and weld the 8 tubes at the flange (at the cylinder head) it will distort because of the welding.

If I do it at the end of the manifold (cut of the flange where the manifold and downpipe met) then I will have issues with the divider (splitter) inside both the manifold and downpipe.

This exhaust is to be mounted on a standard mi.

So my question is where to cut and reangle?

[jackherer 543]

Every one I have ever seen has been cut and welded by the cylinder head flange. They can distort but if you are careful and keep it to a minimum they tend to straighten when bolted up and seal fine. I have had one that was a bit marginal and I got it skimmed flat by a machine shop, several places wouldn't do it due to the difficulty clamping it down straight as its an odd shape but I found somewhere that was able to in the end.

[petert 557]

I'm a wedge man. With tapered washers, new studs, new cone nuts and the correct goo, it will seal perfectly and last indefinitely. It's just too much mucking around cutting and shutting the standard manifold.

 

If you want more power than the standard manifold can deliver, than go extractors.

 

To answer your question, you need to find 6 degrees.

[fast_eddie 0]

Take an old exhaust system with the same flange/fitting that will mate up to the Mi manifold. Cut off the flange part with enough metal left on it to weld to. Source some pipe (mine was stainless) that marries up to the flange, or goes slightly over it to be a little more secure. Weld on first section of your own tube to the flange, offer up newly made flange with your new bit of pipe on, then decide where and and what angle it needs to be cut at. Rinse and repeat in segments, reducing the diameter of the tube(using bits of left over down pipe etc) until it is ready to marry up with your own exhaust system. I did it on my Mi309 and the power gains were impressive when using carbs as well. It takes a bit of patience, a tig or mig welder, a pit is helpful, a sharp hacksaw and grinder essential and Tony Law will be jealous, or maybe not!

Tip-do not fully weld up the downpipe until you have the whole system in place with correct mounts and oil in etc(ie road ready) as it will probably need a little tweeking to fit properly - if it is just tacked you can easily adjust it somewhere.

[stefan 4]

Take an old exhaust system with the same flange/fitting that will mate up to the Mi manifold. Cut off the flange part with enough metal left on it to weld to. Source some pipe (mine was stainless) that marries up to the flange, or goes slightly over it to be a little more secure. Weld on first section of your own tube to the flange, offer up newly made flange with your new bit of pipe on, then decide where and and what angle it needs to be cut at. Rinse and repeat in segments, reducing the diameter of the tube(using bits of left over down pipe etc) until it is ready to marry up with your own exhaust system. I did it on my Mi309 and the power gains were impressive when using carbs as well. It takes a bit of patience, a tig or mig welder, a pit is helpful, a sharp hacksaw and grinder essential and Tony Law will be jealous, or maybe not!

Tip-do not fully weld up the downpipe until you have the whole system in place with correct mounts and oil in etc(ie road ready) as it will probably need a little tweeking to fit properly - if it is just tacked you can easily adjust it somewhere.

 

 

So if I understand correctly, you didn’t reangle the manifold, just the downpipe?

As I understand your new ‘tube’ domwnpipe section doesn’t have that splitter (divider) inside?

So in your experience this (the lack of the divider inside the downpipe) doesn’t reduce power?

If not it makes things somewhat easier.

[jackherer 543]

So if I understand correctly, you didn’t reangle the manifold, just the downpipe?

 

You need to do both. The manifold reangling allows the manifold itself to fit without contacting the bulkhead. The downpipe reangling is so it points directly down the tunnel, not to one side.

 

fast_eddie might not have needed to reangle his manifold because he has a 309?

[fast_eddie 0]

Yeah thats a good point about the 309-not sure about the 205 bulkhead to manifold flange clearance sorry-although from memory the master cylinder contact for the cam cover/cylinder head possibility is identical???

 

By the way, the centre bit in the exhaust made NO difference to power in my car - I would say peak power was higher (just my findings)

Edited July 14, 2010 by fast_eddie

[stefan 4]

Trial fitted the exhaust today, using nuts and washers between the manifold and the head, to angle it down. One of my main concerns was that it will need reangling to the side as well, but now it doesn’t seem that way. Decided to cut the 8 tubes maybe 5-10mm from the flange to avoid distortion of the flange, due to welding, as there isn’t a machine shop willing to skim it because of its uneven shape. If it eventually cracks I’ll weld it up again. Won’t be cutting the tubes all the way through, just enough so that they bend when I hit the manifold with a hammer ( 2,5kg ).

As to the downpipe, it will certainly need shortening, which I’ll do at the top, under the flange.

Then I’ll bolt the downpipe flange to the manifold flange, and see how the downpipe meets with it all. I’m hoping it won’t need any reangling there, just welding it more or less straight up on it's flange. If it goes to one side of the tunnel, which it probably will, I’ll bend the downpipe on a pipe bender, further down, under the divider.