[futureal33]

Hi all.
I am currently shopping around for a new manifold for my Cooper S. I have been doing tons of research on all the different makes/models out there and am still just as confused as when I started!
I have started this thread so people with a milltek cat-back and any aftermarket manifold can put in their comments on noise levels, performance etc etc and any problems with emissions come MOT time, or the emissions warning light.

The main thing I want from a manifold is increased noise, from the already beautifully sounding Milltek cat-back exhaust.
I have read that a freer flowing cat can lead to more noise, as can wider primaries and collectors - but it is difficult to tell from videos and reviews just how loud things really are

SO if you have got an aftermarket manifold and a milltek cat-back please post your comments on your setup here, your help will be very much appreciated!

Thank you

[Richard Crofts]

Milltek to Milltek : Its loud I'm doing my best at the moment to get something half good for you to listen to mate. I know a chap with a Janspeed to Milly (KMS) on Miniaddiction.co.uk theres some video on that sites latest Rolling road day. One of the chaps videod several mani and exhaust car on the rollers.

[futureal33]

Just found this video... I dont think Berthil will mind me posting this too much

http://babelfish.altavista.com/babel...th_milltek.wmv

Thats the MTH manifold and Milltek exhaust - lovely sound isnt it. However, I've read that the MTH has a 400cell CAT - and the more free flowing ones are even louder - such as the GTT 120cell and Milltek 200cell. I cant imagine much being louder than this setup though!

[duncanbanana]

I have the Milltek manifold and Milltek cat back but i have fitted a Supersprint Straight thru centre box to replace the Milltek centre box (fits ok just have to cut down the pipe a bit) i think it sounds great , lot as loud as the Larini with decat

[ScottyBoy]

At the moment ive got a fully standard MCS with a Janspeed manifold and its Great! The accelaration is much improved and it sounds alot better sort of a growl lol! hopefully going with a JCW Cat back Zaust soon as!

[Ant FR]

I've got milltek to milltek and its the best.

Quiet on the cruise, and on the motorway at say 70-80,

but

push the right pedal and all hell breaks loose. Any louder than that is just too barry, race cars don't sound like Halfords Heroe's

From Berthill's video the noise inside with the MTH manifold sounds rediculously loud and rather unpleasent. not so with Milltek to Milltek

[Berthil]

And now I have got a big valve cilinderhead and it's even louder
Good luck with your choice

[Ant FR]

that big valve head make much difference to go go

[alski]

not sure if this is on topic, but thinking on same lines and wonders out loud what about the cat?
are most of the power gains attributed to manifolds down to having a sports cat, or no cat at all?
will the choice of cat make a difference to their sound, would we all be better off looking at new sports cats rather than shiny pipe work?

[ScottyBoy]

Quote: Originally Posted by alski (original)

not sure if this is on topic, but thinking on same lines and wonders out loud what about the cat?
are most of the power gains attributed to manifolds down to having a sports cat, or no cat at all?
will the choice of cat make a difference to their sound, would we all be better off looking at new sports cats rather than shiny pipe work?

The reasons a new manifold will deliver more power is down to the pipe work and the cat as follows!

the standard maifold's pipes are very short and bend almost straight away as soon as the exit the header! when the exhaust gasses are exiting they have to negotiate the bends to exit the car! on a sports maifold the the pipes are alot straighter and therefor more free flowing!

The cat is the part of the manifold which turns the 3 harmful compound gasses in to cardon dioxide inside the cat it has a honeycomb effect were this takes place, in the standard cat it has 400 Cells per square inch (cpsi) so there is alot of cells for the gasses to squeze through! just imgaine sucking on a Maccy D's milkshake straw and then drinking coke through a staw! a janspeed manifold has 200 cpsi as far as im aware and therefor its alot more free flowing so all the gasses produced escape alot quicker and deliver more power!

i may be talkin a load of B*llsh*t there but thats how i think it all works any1 car to explain any better lol!

[futureal33]

Yellow_Mini_Scott>>>

Almost mate - the standard manifold actually has 2 x 400 cell cats I believe, so when you come down to 200cell - its a lot less restrictive...

[alski]

Quote: Originally Posted by futureal33 (original)

Yellow_Mini_Scott>>>

Almost mate - the standard manifold actually has 2 x 400 cell cats I believe, so when you come down to 200cell - its a lot less restrictive...

so if i have this right, 2 x 400 as against 1 x 200 for typical sports cat = 400% less restrictive
to exit gasses
my bet this is far more important than when the bend occurs in a pipe, all other factors being equal,
the worry being when comparing manifolds there is no bench mark
imho they should all state with 200 cell cat otherwise the other figures are meaningless
unless stated for track use and with de-cat

another point, will a 200 cell cat need changing 4 times quicker?

[ScottyBoy]

The Sports cat on a manifold is more than likely the best change on there for it is far less restrictive (just read the Janspeed manifold is 120cpsi from lohen) but the straight pipes 4 -1 have a larger bore and this is another main feature thats makes it alot more free flowing!
hear is a pic of both as you can see the Janspeed manifold pipes are far straighter.





As far as im aware the CAT should last as long as a normal CAT as long as the car is not running lean!
if its running lean then unburnt petrol will be sitting in the cat and will serverly damage it!

[futureal33]

Well guys.... I have gone with the Janspeed manifold (200 cell cat) for a couple of reasons, price being one of the major influences
However, I am confident that it will be a superb manifold and after speaking to a few members with the Janspeed manifold it sounds like it is loud and exactly what i personally was looking for

I am intending to go de-cat next month, after hearing how it sounds with the cat on I will make my mind up wether or not it needs it.

I will make a video as soon as I get it fitted and keep this post updated
Thanks for all the help!

[ScottyBoy]

Cool choice great manifold! you wont regret it! an as i mentioned jus now its a 120cpsi as i just found out.

[futureal33]

Yellow_Mini_Scott - I asked the question yesterday and was told that Janspeed use a 200cell cat now rather than the 120cpi one for emission reasons. Not sure which is correct!!

I was also told that the cat would last just as long as the standard one, but to watch out for backfiring as this is a cat-killer

[ScottyBoy]

You maybe right! im not too sure either as i read it when i stole the pic from the Lohen site! i thought it was a 200cell cat until then so i gues it is!!

[Richard Crofts]

it does kill the cat but it takes some serious state of tune and over rich fueling to get flames that will damage the cat

Don't forget that a cat is a legal requirement on cars built after 1990 (i think this was when, but defo on a car only the age of a MINI). To drive on the public roads with no cat is illegal and you can be prosicuted...de-cats are for track and rally use really. But there are folks running decats on the road and getting away with it but its a risk i am not willing to take so i got the cheaper non-decatable milltek manifold.

[Ant FR]

1992, the h-j reg change over time.

I just hope it is ok on cruise and not too boomy. I paid the same price as the Janspeed for my milltek,

[chrisflyer]

Hi,

I see you have gone for the janspeed were you aware the GT manifold is built by janspeed specially for GT and is a better manifold as agreed by Janspeed.