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Discussion Starter · #1 ·
Now I have done a bit of research and I thought you guys might be able to help.

i have heard that the 325 manifold has a much wider air intake than the standard 328 one and that if I replaced my manifold with this, I could increase my BHP by up to 30.

Is this true? If so does anyone know where i can get a 325 manifold from, how much and are there any other parts that need to come with it.?

I saw one on ebay a while back for £80 was this a good price?
 

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Yes this is true, The germans used a restrictive manifold on the 328 to meet german emissions laws i think, i maybe wrong. But yes, if you fit a 325 manifold it will increase you BHP considerably.

You will need a new set of manifold gaskets, but i dont believe there is much more to it than that, hopefully somebody else can confirm this...

Keep an eye out on ebay, they sometimes are on there cheap, I would suggest a scrapyard, but they are no place for a lady...:D
Maybe someone at the scrapyard will remove it for you? other than that just keep an eye out on the bay.... :thumbsup
 

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Discussion Starter · #4 ·
Wont be buying it just yet ;)
Was just a heads up for future plans.

Also my car currently has a Gruppe induction kit on it, which is about the size of my head.
Is this any good, its carbon fibre, thats all I care about lol. (was on the car when i purchased it)
 

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http://www.team-bar.com/diy_m50manifold.htm

This tells you how its done, it is not as straight forward as one off and new one on but its not far off. Its probably an Idea to get the car remapped after you change the manifold, and if you are going to do this you might as well smooth out the throttle body first. You should be able to get up to 40Bhp.
 

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do it as a kit, buy all the stuff you need in one, so that manifold, throttle body, remap, cold air intake etc, collect all the bits and then arrange to have the car of the road for a few days and get it sorted in one, since you are going to goto that kind of effort its well worth doing a complete overhaul on all the fluids aswell, the power difference if done this way will be shocking as its a huge lump of extra power in one and it will be well worth the effort, might be an idea to upgrade brakes/suspension etc at the same time.
 

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Discussion Starter · #7 ·
Hang on im confused..

What is the M50 manifold?

I already have a 328, dont I need a manifold from a 325?
 

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M50 is the engine code for the early 6 cylinder engines. Your 328 engine is an M52. Just make sure you get the manifold from a 325i with the M50 2.5 engine. :thumbsup
Just to confuse you more there is a 2.litre M50 engine. Avoid that manifold coz its smaller. :confused
 

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Discussion Starter · #9 ·
LMao.. Ok thanks think I got that.

Man its not going to be fun finding this lol. When I ever get round to it!
 

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Like someone else said, when you are ready just buy the whole kit. It makes life so much easier having everything you need rather than hunting around for various bits. :thumbsup
 

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Also my car currently has a Gruppe induction kit on it, which is about the size of my head.
Is this any good, its carbon fibre, thats all I care about lol. (was on the car when i purchased it)
It's probably Gruppe M relica as the originals are stupidly expensive. Saying that, the reps are still £150-200.

Some of the figures being thrown around sound a little optimistic to me. If I was you I'd do the manifold first (forget the throttle body) and then get a remap.

If you want to go further than that, it would then be cams but I'd probably call it a day and start looking at the diff and sorting out the suspension.

Ian
 

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Get your car check first with a good service, there is no point trying to improve a car for instance when it may have lost 20% due to poor injectors, i.e. you can't polish a turd...
 

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Some of the figures being thrown around sound a little optimistic to me. If I was you I'd do the manifold first (forget the throttle body) and then get a remap.


Ian
I dunno, if you are going to the effort of changing the manifold, it is not much hassle to do the throttle body too. Its all about peak air flow and there is no point choking it at the TB? Just my opinion
 

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Does it choke it? If so what gains would you get for your money? 2-3bhp at most for £100+? I have changed TB's before and it made no noticeable difference. There are other things you could do to improve the airflow through the TB like bypassing the throttle body coolant or even deleting the ASC.

It's not all about peak air flow either. The manifold design and intake runner length has a big effect on the engines characteristics. The reason the M50 works so well on the M52is that it was designed for a smaller engine.
 

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Discussion Starter · #16 ·
Blimey im learning lots from this thread.. :D lol

Dont think its a replica, unless the replicas are worth about 700 -800 .. Its real as far as im aware/been told by a few people.
 

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Blimey im learning lots from this thread.. :D lol

Dont think its a replica, unless the replicas are worth about 700 -800 .. Its real as far as im aware/been told by a few people.

Come on then, don't be shy... Post the pictures up







Yes... and this time I mean of the induction kit:sarcastic



:thumbsup
 

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Discussion Starter · #18 ·
Lol oo but that means going out in the dark. I will try and get some tomorrow during the day :)

But its real carbon fibre, do the replicas have real carbon?
 

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when i owned a MG zr 1400 the i changed the 48mm TB to a 52mmTB from a higher spec model including the VVC head, so if i were to change the intake system on my 318is to a 320i , i would need a remap as i can get hold of a complete 320 intake system and cylinder head,Bearing in mind i'll have to use the 318 injectors,and full Janspeed exhaust system...Am i right ??

or would it be better to cam it an have a remap??
 

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when i owned a MG zr 1400 the i changed the 48mm TB to a 52mmTB from a higher spec model including the VVC head, so if i were to change the intake system on my 318is to a 320i , i would need a remap as i can get hold of a complete 320 intake system and cylinder head,Bearing in mind i'll have to use the 318 injectors,and full Janspeed exhaust system...Am i right ??

or would it be better to cam it an have a remap??
318 is a 4 cyl and the 320 is a 6 cyl so be care full what you go buying :)
 
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