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MG MGF Technical - New MS Manifold


Please queue in an orderly fasion... :

http://www.mikesatur.co.uk/images/manifoldss42.jpg

Price around the £410 mark I think - I may be wrong.

Is this what Mr.Bell has been waiting for? :-)

P.
Paul Nothard

Nice bit of kit; it even has the flexi-pipe section :o)
Rob Bell

Wheres the cat?
Will Munns

It'll bolt on to the flange at the end of the manifold - just as the cat does to the end of the standard down pipe.

As I said - a nice bit of kit :o)

Good work Mike.
Rob Bell

Ah, OK, I just wondered if it were 'straight to box' or 'to cat' I wonder how it looks on a rolling road
Will Munns

I think we'll have fun finding out :o)
Rob Bell

You may have to borrow my car to give it a real test :0)
tim woolcott

You might need a larger bore manifold Tim! ;oD LOL
Rob Bell

£399.50inc vat
mike

Oh bugger, you had to do it didn't you Mike! You waited 'till i was completely skint and then released this! ;-)

Sorely tempted but can't until Scarlet is sorted out (any progress with the quote?)

SF
Scarlet Fever

Hmmmmmmmmm.........£400.00 Made from Titanium is it?

Mega
Mega

This is just soooo tempting, but no, i will control myself.

SF
Scarlet Fever

Very tempting, true. Couple of questions though:

1. what can be expected torque/power-wise?

2. there's no way to mount the famous exhaust support bracket, any chance to get this into the "final" production run? I think there was some discussion the bracket could prevent extra stress to the head gasket

3. the oxygen sensor fits at the 2-1 section, IMHO a very good idea, the original spot (on older F's) is a real pain.
Andreas H

>>1. what can be expected torque/power-wise?<<

Not been tested yet Andreas - but if it performs as well as the EBD manifold, then something in the ball park of a 5-10% gain in mid-range torque :o))
Rob Bell

Rob, how much is the EBD version?

Also, any idea how this compares price wise with the OE equipment, bearing in mind it replaces the manifold AND the flexipipe?

SF
Scarlet Fever

EBD = £400+vat, but there isn't one for the F.

it looks very similar to my janspeed one.
Kingsley

Kingsley, it IS a Janspeed one. ;o)
Rob Bell

So the nearest thing to competition is the EBD one, this is £400.00 + VAT (@ 17.5% = £70.00) = £470.00

Mike's one, which is made by Janspeed (allegedly) is £399.50 inc VAT.

I make this a saving of £70.50 for one that will fit an MGF as opposed to one that only fits an Elise.

Anyone know the cost of an MGR front pipe (flexi pipe) and Manifold? Just trying to get a price comparison.

SF
Scarlet Fever

Mike's s/s down pipe alone costs 162 quid Andy - no idea about the nasty mild steel manifold...
Rob Bell

So, 5-10% on mid range torque eh.....! Where does that put me then....


Do I have enough fingers..... 139.7lbft @ 5567 plus 5-10% that'll be 7-14lbft....so could be 147-154lbft surely impossible!!!!! Where's Dave Andrews....?
tim woolcott

Hi Guys. Nice work Mike!
Can anyone explain me what evokes this 5%-10% benefit.
Is it the long 2 and short 1 in the 4-2-1 configuration? Less restriction?
There are other systems out there which use 2 flexi pipes which in turn end up in the 1 from above.
If I´d understand the physics, I might be able to determine the better (?)system. Not?

t.i.a.
David

David

Tim - probably more like 7 lb.ft - if the EBD is anything to go by (not guaranteed of course - we're only speculating at the present time).

Regarding exhaust manifolds, hasn't Dave Walker got some explanatory words on the net somewhere? I know he's written an article in CCC about exactly this subject in the past.

4-2-1 manifold.

As it's name suggests David, the manifold has four long primary pipes from each of the the cylinder head's exhaust ports (one for each cylinder). These four pipes then merge to two separate pipes (2 into each) - these are the secondary pipes, and again, are usually pretty long. Finally, these two pipes merge into a single pipe, which on Mike's system is at the flexipipe, or on the EBD, practically at the catalyst mounting flange.

The shape and length of these pipes have a significant effect on the manifolds performance. There is a lot of physics/ fluid dynamics going on!

One aspect is back pressure. Broadly, these manifolds have a lower resistance to flow than the standard cast iron affair - which is good. But back pressure also has an effect on combustion camber filling and exhaust extraction: it gets complicated, as other factors such as cam durations need to be factored in... gulp!

The length of the tubes is important, as are their shapes and the way that the pipes merge. Another way of thinking about manifolds is in terms of a trombone: changing the length of the pipe alters the frequency of the sound - or pressure waves. Interestingly, if you can tune the negative pressure pulses to coincide with exhaust gas expulsion from the combustion chamber, then you have a recipe for getting the exhaust gas out of the engine quicker and with less resistance. And less resistance means that the engine need not waste more power on actively pumping exhaust gases out of the combustion chamber...

There are probably other aspects that I've forgotten (or don't know about!!!), but you get the jist. Basically, there can be a huge difference between what is a 'good' exhaust manifold, and what is a 'bad' manifold.

The standard manifold is pretty poor: the design is not great, and moreover, the thing is welded together on the inside, meaning dirty circumferential welds that effectively reduce the inner diameter of the pipes! Even using the standard manifold with these welds 'cleaned up' can result in surprising gains as Andy G will testify (he has one that Mike 'prepared earlier' ;o))

Worth the same money as a stainless steel exhaust? I'd say so - especially as the gains are probably greater overall.
Rob Bell

Well Rob, yet again I am astonished by the speed and length of your answers. Highly appreciated!!

I´ve read Andy G (*LOL* ref. bro of Ali G) comment on the "other" board. And true, simple porting and cleaning the inlet flanges, greatly improved flow.

Cheers,
David. (waiting for the £ to fall a little more!)
David

Booyakasha ... innit?
AndyG

no pun intended Andy!
cheers,
David
david

Titanium? £600.00, special order only;-)
Mike.
mike

£600? For real ... ?

>-)))
AndyG

mike, if you could build in titanium for that sort of price you ought to be taking a look in to the 2-wheel market - there are more people with more money riding around on Ducatis that are prepared to pay £1000 + for a system in unaffordium.
JohnP

see mgf general re mikes manifold
andrew

I had the EBD manifold with flexi piece on my Elise and did a before and after rroad testat Emeralds.
compared it with the standard manifold as on the Elise and MGF;
NO gain in power or torque at all !

to make place for the flexi bit the secondary pipes were shortened, and the length of the pipes is essential for the power/torque gain.

that is why EBD don't produce them anymore with flexi bit.

I don't know Mikes manifold, but I don't think you ca compare it with the standard EBD (that does give more power (and I think it will fit the MGF too).

Bob vanM
Bob vanM

Bob,

EBD manifold will NOT fit an MGF because the flexi bit is ESSENTIAL. The Elise has firmer engine mounts than the F/TF, this means that the engine moves more in an F/TF. The result of this is that although it is possible to fit an EBD manifold to an F/TF, after a few Ks driving, you would need a new one as the welds would be cracked (or worse, damage to the head).

There was talk a while ago about replacing the catalyst with a flexible section, this then could be mated to the EBD manifold, but TTBOMK this never happened.

Length of primaries and secondaries are a huge factor in manifold design, but so is flow dynamics, bore diameter and tuning the system to suit the engine resonances. This does not necessarily boil down to "long pipes good, short pipes bad", they have to be specific lengths to get the best result and the gasses should merge in a laminar flow as opposed to a turbulent one - this is increasingly difficult as the efficiency of the manifold increases as flow dynamics dictate that fast moving gases have a greater tendacy toward turbulence. Overall it is a very complicated piece of design work to get it right.

From my point of view, i don't know whether Mike's manifold is good or not. What i do know is that it looks well made and seems to have been designed to suit the above criteria. I also know that the OE manifold is cr*p, with very poor flow dynamics, made worse by welds which intrude into the bore. So from this point of view, it should be at least some improvement.

Lastly, Rolling roads do not produce reliable data, they are at best an indicator of the performance of a vehicle under specific conditions - this is not a real world test and therefore any data gained can not be relied upon. They are also subject to changes in the environment, like humidity, temperature and even operator error. Even back-to-back RR sessions on the same car, on the same RR, on the same day will show fluctuations. This is especially important if the expected gains are fairly small - they may be cancelled out by something as simple as the sky clouding over between RR runs.

Rolling road data sells products, it does not prove performance.

SF
Scarlet Fever

What are the secondary and primary pipes on this sytem?
4-2-1

4: primary?
2: secondary?

David.
David

Hi Bob,

I think you mailed me regarding the EBD with flexi before - and warned me that this system probably wasn't worth the 400 quid being asked... thanks :o)

You are right, it is inappropriate to compare this new manifold with the EBD until there are road and RR comparisons - but we shall be using the EBD as a 'gold standard' to bench mark the MS manifold.

Does the EBD fit the F? It ought to, but Kingsley found that with the EBD designed to fit around the aircon compressor, the primary pipes fouled a cross rail behind the engine. Whether this also applies to the 'standard' EBD is an open question - it probably does :o( We'll have to get Graham to build a new pattern of manifold to fit the F, unfortunately :o(

Andy makes a good point regarding engine movement - and rightly emphasises the need for a flexible section in the pipework. In fact, this is proving to be the Elise experience too - with many early systems, without flexipipe fitment, fracturing with prolonged use. :o( The commonest solution to this has been to fit Greary's stiffer engine steady bush - and this could be an option on the MGF too. However, remember that the F is a heavier car than the Elise, so expect more torque reaction on engaging drive to the road wheels, and therefore more movement.

A flexipipe is going to be essential IMO.
Rob Bell

David,

You are correct.

Primary pipes are the first ones out of the head, on a 1.8K there are 4 of them (one for each cylinder). Secondaries are the next set down the manifold, on Mike's one there are two of them.

SF
Scarlet Fever

Thanks for confirmation scarlet, judging from MS´s pictures, primary pipes are pretty long! So this should give nice gains!
Myself, I´ve been thinking about the Hi-Flow/performance manifold, these have spaghetti type primary pipes which are quite long too.

http://www.hi-flow.com./HPExhaustSystems_files/HI-FLOW%20MGF%20EXT.JPG
and
http://www.hi-flow.com./HPExhaustSystems_files/HI-FLOW%20MGF%20EXH.JPG

I´ve posted performance gain with that system on this board some time ago. Pitty, it was backed up by quad throttle body assembly. So couldn´t really differ about their individual performance.

PC crashed, so lost the original email. It should be in the archives though,

cheers,
David.
David

Hi guys,

I fitted Mike's new exhaust manifold on Friday night and I am pleased with it. It feels quicker from the midrange up to the limiter, getting better as the revs rise.

I intend taking the car to the dyno to see what it is producing, but also to set the cams up, so it won't be a direct before and after comparison.

I still need to fit exhaust wrap insulation, as I had to remove the two heat shields to get it in, so the alternator might get a bit warm. The only other problem you might face is removing the lambda probe from the old manifold, it's tight!

The manifold is manufactured by Janspeed, as it has their stickers and tape on it.

Cheers

Alastair

PS If anyone wants an old manifold with the internals reworked and Mike's SS downpipe make me an offer. :-)

Alastair McLeod

This thread was discussed between 09/06/2003 and 16/06/2003

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