Mi16 4-2-1 Manifold

[JeffR 51]

Hi all,

 

I'm looking for peoples' feedback from their experience using a 4-2-1 exhaust manifold for

the 1.9 litre Mi engine.

 

In searching I found plenty about cracked welds, poor fit, gussets for strengthening, bulkhead modifications, etc. but no real evidence or back-to-back comparisons of their performance increase especially on engines making lots of power.

 

All the designs (Maniflow, Miles, Longman, Des, AB M/sport) seem to be almost

identical, so is that confirmation that the basic design, pipe diameter, primary & secondary

lengths are the ideal spec for these engines?

 

I need one for a 405 track car, & nothing is available here in Australia & since the car is up on stands without a head, getting it around for a custom fit is out of the question.

 

I've spoken with most of the above & Miles especially has been helpful in addressing most questions & it seems in order to break the 200 horsepower barrier I'm going to need something other than the standard 8 pipe.

 

Also, is there anyone with experience of thermal coatings? I've read the pros & cons of manifold wrap & would prefer thermal coatings as an alternative.

 

Thanks

Edited November 27, 2008 by JeffR

[DrSarty 90 1 Cars]

Wraps are cheap and crap.

 

I've done mine, and I'm sure it can be done better as I've seen on other cars, but you need loads and it's very fiddly.

 

As it's quite expensive too (well it gets that way as learn you need more and more), personally I would go for the ceramic coating approach. This will no doubt be harder wearing, better looking and probably better performing than wrap. I suspect a manifold done properly will be around $800 AUS though (£400).

 

The reason there are aftermarket 4-2-1 systems is because they go in WITHOUT further modification, however this may only be the case with the alloy XU9 block. I say may, because the XU10 iron block being 11mm taller, CAN cause downpipe to bulkhead fouling issues, however with our cars being French built, tolerances can certainly fluctuate, so you may get issues on one install and not on another.

 

Performance wise *readies himself for a torrent of abuse* I reckon there's not much difference between any of the aftermarkets versus the standard (reangled or with an angle plate mod) in terms of tangible power gains or losses; zilch IMHO. If someone comes on and shouts that a Maniflow for example will net you 8bhp+ and be able to prove it, I'll eat some breather mayo!

 

As you want it for a track car, I'd just find one that's well built and gives the best access to the studs/bolts/nuts for easy fitting and removal. I'm sure you could do some test fitting with you car as is to try a few out for bulkhead clearance, but as you have the XU9 in there I doubt you'll have issues.

 

My Maniflow is well built, and I can't imagine Miles selling anything but the best. As you communicate with him, trust him then do the deal with him. That's my real honest advice.

Edited November 27, 2008 by DrSarty

[brumster 135 1 Cars]

All the designs (Maniflow, Miles, Longman, Des, AB M/sport) seem to be almost

 

I'm not entirely sure there's any difference at all; I don't know who makes them, probably Maniflow, and then everyone puts their 'brand' name to them hoping people think they are in some way different or more marketable. Certainly my "Longman" manifold, sourced through AB M/sport, is stamped a Maniflow

 

This happens a lot with tuning parts. Bushes, lower arms, sump guards, plating kits, etc. everyone wants you to think you're buying some unique, branded, better-than-the-others kit but I have very little faith that they're any different.

 

Anyway, good praises from me on the AB Longiflow manifold!! The bulkhead didn't need modifying as such, but the seam that bridges the bulkhead where the manifold drops down near the gear linkage did need 'creasing' out of the way as it was too close for comfort.

 

Performance wise *readies himself for a torrent of abuse* I reckon there's not much difference between any of the aftermarkets versus the standard (reangled or with an angle plate mod) in terms of tangible power gains or losses; zilch IMHO. If someone comes on and shouts that a Maniflow for example will net you 8bhp+ and be able to prove it, I'll eat some breather mayo!

 

No quibbles with that statement here, assuming you mean just swapping on a standard engine with nothing else whatsoever. I would imagine any differences would be pretty marginal to not be worth it.

Edited November 27, 2008 by brumster

[Miles 331 1 Cars]

I can say that Manifold, Longman, Pugspares (Depending who they deal with at the time) are all the same, I would guess that most companies get them from Maniflow,

I can say mine do not but the design is similair as they all need to fit the same space, I also think that maniflow sell there's saying it will fit the XU10 engine which in a way it will it just won;t fit in a 205 as DS has said the engine's taller.

I have made revission's to mine to fit the 205 better with bending the top downpipe slightly more to gain clearance on the bulkhead along with slightly larger holes so they can fit over the studs better which may help fitting the XU10 engine but I will find out next year.

As for perforamce gain's you should see a improvement in torque than anything else but as the std manifold is such a pig to remove I don;t think may have done a back to back for that very reason it would cost a fortune in time and RR time.

Welding I can only talk from the experance of mine and to date with a good 5 years of supplying them I don;t think I have had any problems, Do not wrap them as this causes scaling (Like sunburn) and will ruin the manifold in no time at all.

[jackherer 543]

Performance wise *readies himself for a torrent of abuse* I reckon there's not much difference between any of the aftermarkets versus the standard (reangled or with an angle plate mod) in terms of tangible power gains or losses; zilch IMHO. If someone comes on and shouts that a Maniflow for example will net you 8bhp+ and be able to prove it, I'll eat some breather mayo!

 

I can't prove anything but I took one off for rewelding due to some minor cracks and replaced it temporarily with a standard manifold (2.0 S16 cast one, not a 1.9 Mi16 8 branch) which made the car noticeably slower, I wasn't expecting to notice anything at all TBH, except maybe a change in noise. Replaced it and performance is definitely better, I would lay money on a back to back RR showing a significant increase right through the rev range.

 

You're right about the fit being worse on 2.0s, this one did fit fine in one shell but my mate wrote it off and when I reshelled it the bulkhead was touching the same mani in the new shell.

[JeffR 51]

I'm sure the 8 pipe manifold will hold me back with this spec-

 

11.2:1 CR, 48mm t/bs, BV head, 1928cc, Motec, Cams, l&b bottom-end, etc.

 

If 4-2-1's give more torque that will be a bonus in my 1100kg 405.

 

Sarty, I've been offered thermal coating services cheap-(mates rates) so too good to knock back.

 

Going by the 205's reputation for great build quality & fit, I'm hoping my 405 is more or less a similar shape to the original!

 

Thanks all

[James_m 0]

Not specifically related to this example, but ive been a huge sceptic of manifold/exhaust changes making any significent changes to power, but i was recently made a convert when i switched from a UKDM manifold to JDM manifold on my integra type R. It noticably gained throughout the entire rev range, and has been the best N/A mod ive ever done.

Perhaps us 205 Gti community who seem to ignore any exhaust mods, running exhaust systems designed for 125bhp have been missing out?

[Miles 331 1 Cars]

There is allot in the system's by any mean's, I know people say on the 8v's there's not much in them but a good exhaust manifold is worth allot of BHP, same goes for the 16v's

[d-9 0]

Exhaust systems do make a big difference on modified engines, not convinced that youd notice on a standard engine. I found going from a downpipe without a split to a downpipe with a split made a huge difference to the torque of my cam'd MI, no longer getting out dragged by navaras when its off-cam

 

Going from magnex 4 branch to a standard mani on my old 8v goodwood killed the top end, much less happy to pull to the limiter.

[rubyna 4 1 Cars]

I got a Magnex on my 8valve and it made a considerable difference all through the rev range, id go for the

magnex every time over the o.e. ones..

[JeffR 51]

What exhaust manifold are the XU9J4 members using in their big horsepower 205/309/405's (other than the GTi6 & GTi16 ones)?

[Francesco 2 1 Cars]

I'm using a standard 309 GTi16 manifold for my 205 GTi Mi16, a sollution that is used more often in the Netherlands for a 205 Mi16. The design is different from the standard Mi16 one. Don't know how much better it is as the after market ones, I do know from experinece in other Peugeot models that a after market manifold (and exhaust system) can make a noticible difference in performance.

Edited December 10, 2008 by Francesco

[Cameron 16]

Don't think any of the ports on aftermarket manifolds actually match the head due to it being twin port, so I guess none of them are really that amazing.

[DrSarty 90 1 Cars]

You say that, but when I said in another post that aftermarket 4-2-1 manifolds such as the generic Maniflow one 'probably' don't make that much difference, either Jackherer or PugTorque said when they had to swap out and back again they noticed a considerable difference in power delivery.

 

I suspect there are more ideal manifold designs, in fact I think the '6 one is rather sexy, but whilst it may not be beautiful - as I've learnt - sometimes it's much more function over form.

 

It's probably more important to try and match the inlet - outlet phasing characteristics, which I believe Sandy & Eeyore's inlets for bodies and carbs do quite nicely with this Maniflow type 4-2-1.

Edited December 10, 2008 by DrSarty

[Cameron 16]

Oh, no I didn't mean they don't make a difference, I just meant they don't make a huge difference, or as big a difference as they could with the proper flange and primaries. I'll see if I can nick the pictures of the old 406BTCC manifold BTB used to make, its pretty special.

[danpug 1]

I can't comment on power gains but i've used both a maniflow and one of miles manifolds and had no problems whatsoever with either, one of them was a good few years old too.

[B1ack_Mi16 67]

I'm using a standard 309 GTi16 manifold for my 205 GTi Mi16, a sollution that is used more often in the Netherlands for a 205 Mi16. The design is different from the standard Mi16 one. Don't know how much better it is as the after market ones, I do know from experinece in other Peugeot models that a after market manifold (and exhaust system) can make a noticible difference in performance.

 

Mine produces 250bhp with the 309 GTi16 manifold, only mod I made was to put a 2.5" V-band flange on the outlet instead of the standard 2.25" peugeot flange fitment.

This was mostly due to makeing custom downpipe anyway.

[JeffR 51]

Mine produces 250bhp with the 309 GTi16 manifold, only mod I made was to put a 2.5" V-band flange on the outlet instead of the standard 2.25" peugeot flange fitment.

This was mostly due to makeing custom downpipe anyway.

 

Black_Mi16,

 

Are you still on hydraulic lifters or have you gone solids? What rpm to make 250hp?

 

BTW, I have a GTi16 modified spaghetti manifold for sale here if it's of interest particularly to the Euro members-

 

http://forum.205gtidrivers.com/index.php?showtopic=98214

 

Thanks

[welshpug 1,621]

Jeff, how close is the GTi16 manifold to the ARB and does the Downpipe line up to it?

 

tempted to try it on a 2.0 if I can get it to fit.

[B1ack_Mi16 67]

Black_Mi16,

 

Are you still on hydraulic lifters or have you gone solids? What rpm to make 250hp?

 

BTW, I have a GTi16 modified spaghetti manifold for sale here if it's of interest particularly to the Euro members-

 

http://forum.205gtidrivers.com/index.php?showtopic=98214

 

Thanks

 

It's on solid lifters, but as it's a 2.3 litre it makes 250-260bhp somewhere at 7500rpm with a still rising powercurve, but I didn't dare to take it above 8000rpm on the rollers.

 

I think with those revs it's still possible to use hydraulics, however solids feel more confident with such high lifts and spring-forces.

[JeffR 51]

Jeff, how close is the GTi16 manifold to the ARB and does the Downpipe line up to it?

 

tempted to try it on a 2.0 if I can get it to fit.

 

From memory it wasn't all that much needed to clear the arb.I reckon the extra height of the XU10 block would be an advantage for clearance.

 

The outlet angle is a bit different, & closer to the g/box which would require a re-weld of the downpipe.

 

The firewall may need a slight reshape too.