Mi16 Downpipe Mods-manifold Clearance

[newdean0 0]

As above. Most of the posts I have seen use cutting/rewelding the downpipe when the pipe is resting on the cross member of the subframe and to aid alignment with the exhaust hangers. My manifold (standard mi with QEP plate) is not central in the tunnel so the pipe rests against the seam. I can't see how removing a section of pipe helps in this instance or is there a bit of angling involved too?

 

Also, what clearance is generally acceptable. Even with some creative welding I can't see me getting greater than 5mm, and thats with the heat shield removed and it's retaining studs ground flat!

[t16ryan 1]

buy a 4 branch when the manifold get reangled its a bodge as it was made to be like that you cant just cut and reangle it you will lose power, seen new 4 brach fot 400 or on the net as little as 275, its worth it in the long run

[pacey205 2]

Poppycock reangling the exhaust shouldnt loose you any power at all. If you re-angle it properly the change is minimal really anyway. Its not like you introducing any tight bends or restrictions into the system but just reangling the angle of the flange (assuming that is where you are reangling it of course).

 

Yes a 4-branch is probably easier and maybe a little neater but if you havent got that sort of money lying around then the commond way of reangling the exhaust poses no real downsides as far as I can see.

 

Michael

[t16ryan 1]

fitted one too my mates that was done by a known pug specialist on ebay not naming anyone, and looked ok fitted it and was blowing slightly in places, he paid £80 plus his old manifold, i not being funny but for a extra £200 best to get 4 branch,, power does decrease as its a science trying to get all the exhaust gases out evenly mates one RR 8 bhp more.

 

its not just the flange that gets reangled its close to where it bolts onto the head all 8 pipes were cut and re welded

[Pugnut 9 1 Cars]

if it was blowing it was bound to be down on power?

[Veero 1]

I had a 4 branch from a certian manufacturer which wouldn't clear the bulkhead on standard engine mounts. I phoned up and the guy insisted I had to fit a longer lower fork as on standard ones the engine wouldnt go in. I gave up arguing that it would fit since Pug designed them to run at that angle and that yes actually it did fit in my engine bay and was in fact running. His other suggestion was to bend the 2 branches. To have to do that to a magical 4 branch supposedly custom engineered to fit an Mi in a 205 it seemed a bit of a piss take to me that I should have to do that after shelling out £350 for the system. Luckily for me I had bought it second hand and the seller bought it back off me when I told him it wouldnt fit.

 

Standard Mi manifold and angling plate all the way.

 

Veero

Edited June 12, 2006 by Veero

[t16ryan 1]

his was blowing he sent it back and i refitted it then it was RR then 4 months later i fitted Bespoke 4 branch he had it RR again and was 8 bhp up, Bespoke manifold fitted perfect no need to extened the bottom mount at all,

[jackherer 543]

everyone is talking about manifolds and thats not whats been asked, newdean0 has a QEP reangling wedge so his manifold is sorted, hes asking about the downpipe and how to mod it.

 

you do need to reangle the flange on the downpipe to get it to point straight down the tunnel and also shorten it a bit further down so the hangers align and the tailpipe doesnt stick out too far.

[Kev-G 1]

his was blowing he sent it back and i refitted it then it was RR then 4 months later i fitted Bespoke 4 branch he had it RR again and was 8 bhp up, Bespoke manifold fitted perfect no need to extened the bottom mount at all,

 

But what was the comparison between the re-angled and the un-modified std. 8 branch manifold?

 

If no difference then your arguement goes out the window....

 

All your proving so far is that a 4 branch manifold showed a gain over a 'std.' manifold.

 

As for the original question, agree with jackherer.

[petert 586]

My manifold (standard mi with QEP plate) is not central in the tunnel so the pipe rests against the seam.

 

Sounds like Matt has not used enough angle. The plates I make are angled at 6 deg. which usually clears the seam. I increased them from 5 to 6 for this very reason. If clearance is a problem get the angle grinder out and remove some of the seam.

[newdean0 0]

Thanks Jackherer, I'll get the flange re-angled and se if that fits better. In my particular case the plate increases the droop of the manifold off the back of the engine enough to clear the bulkhead but the problem seems to be that the manifold exit sits too far to the driver's side of the engine bay. It almost seems like I need a plate that increases the downward drop of the manifold and points it off the to passenger side by a few degrees too.

[James_R 3]

I've got a hybrid XU10 block'd Mi and found the X-sport manifold hits the bulkhead. But the when I had my XU9 Mi in there iw as fine, and that's what the manifold was designed for. I'm swapping back to a XU9 Mi for several reasons this being on of the. But it seems that the advice on the 2L bottom end'd enignes is to dink a 5mm deep depression by the bulk head to gove the clearance back, lost from the taller block.

[Man3 0]

I have a cut and re-angled one and theres loads of clearance between the downpipe and bulkhead (the downpipe didn't need any mods and doesn't blow at all). I think that once the angle of the manifold is correct, you shouldn't have any problems with side to side clearance, from what i remember the manifold exits slightly to one side.

 

I was talking to BTB exhausts yesterday about a manifold for the mi16 conversion. As it happens they currently have a 205 Mi16 from Track and race car magazine in the workshop for a complete system. When it came in the car had a re-angling plate fitted and upon tightening it seems that some side loads have been placed on the studs as they were all bent when they took the manifold off. Maybe a similar thing has happened with yours and resulted in the manifold shifting upwards slightly.