M52 manifold swap

[Slam]

been gathering bits, some of you may remember my post about finding the 3.0 engine at work well I've taken the manifold and it now sits in my garage. The engine had been there so long there was a nest in the throttle body hole. Anyway my free manifold has already mounted up to £100 new disa valve new gasket throttle body adapter and new vacuum blanks. Now the interesting part will be when I remove the existing manifold as in my history folder there is an invoice for £1000 for modified inlet manifold and big bore throttle body. The car as it is does not seem to peater off at high revs so I may be wasting my time and money but it will have the larger disa valve whether that makes any difference who knows.

 

[windym]

Do you have the m52 or the m52tu engine?

Andy

 

[Slam]

My car is the TU engine.

 

[Ryan]

I've been looking into changing my M54 B22 for the B30. I'm just curious as to how much difference it would make??? Any ideas on the improvement before one goes investing £100 for manifold and new gaskets?

 

[Slam]

I think it's about 10-15 bhp

 

[Sean d]

I've been looking into changing my M54 B22 for the B30. I'm just curious as to how much difference it would make??? Any ideas on the improvement before one goes investing £100 for manifold and new gaskets?

By all accounts on dyno it can be 20 plus on a 2.8 but its all top end power and you may even lose some lower end

 

[Mazza]

My car is the TU engine.

I didn’t know Sainsbury’s did engines

 

[andyglym]

By all accounts on dyno it can be 20 plus on a 2.8 but its all top end power and you may even lose some lower end

You need a remap to gain the lost lower end stuff mate post the manifold swap.

 

[t-tony]

You need a remap to gain the lost lower end stuff mate post the manifold swap.

@Antm72 had his done and when I drove it back to ours last spring it had oodles of low end torque made town driving much easier less gear changing.

Tony.

 

[andyglym]

@Antm72 had his done and when I drove it back to ours last spring it had oodles of low end torque made town driving much easier less gear changing.

Tony.

Thanks mate, interesting. All the reviews state that you lose low end torque, even the major sellers

 

[Dino D]

Thanks mate, interesting. All the reviews state that you lose low end torque, even the major sellers

I believe Anys one is a TU so a bit different effect as it’s dual vanos I expect.

 

[t-tony]

I believe Anys one is a TU so a bit different effect as it’s dual vanos I expect.

Not sure Dino, could be twin vanos. All I can say is how it drove for me comparing to my Z4 3.0.

Tony.

 

[gookah]

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[Slam]

It will be interesting to see what has been done to my existing manifold as it doesn't seem to run out of puff at present.

 

[Portmyster]

Hi slam, we never got chance to speak. Yes when I owened the car the company machined the existing manifold and the TB butterfly was larger too CA automotive did this a lot with the 5 series and did articles, still have the emails aoncould pass on. I would think that there should be no difference but you can swap back? The car when I owned seemed to keep going really well in the upper revs. The CA automotive stated engine was now par with 3.0 and they gave me good price to have cams and valves also, wish I’d have done this at the time. Think lighter fly wheel, pullies would work a treat on that engine.

 

[gookah]

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[Slam]

there are 3 sizes of DISA valve for the twin vanos TU engines.

View attachment 85653

M54B30 3.0 DISA 11617544805 / 750 2 275 fitted to the 3.0 engine, the largest DISA, with the full D Tube manifold

M54B25 2.5 DISA 11617544806 / 750 2 269 fitted to 2.2 (& 2.5) engines, medium sized DISA but with a full D Tube manifold

M52 2.8 DISA 11611440049 / 143 2 557 fitted to the 2.0 & 2.8 engines, smallest DISA and restricted oval tube manifold

if you have already had the manifold changed then it is easy to find out by removing the DISA valve (two bolts) and looking for the part number (in red) above.
As each different manifold has a different size DISA, and you cannot use a different size DISA in anything other than in the relevant manifold, you will know which manifold you then have.


View attachment 85656
Full D ports v restricted oval ports shown above



Also by looking at the above table,
it shows that if you have a 2.0 or a 2.8 you will get great gains with the 2.2/2.5 manifold, and an even bigger gain with the 3.0 manifold.

If you have a 2.2 you can fit the 3.0 manifold but wont see such a big difference, as your tubes are already fully ported, however the 3.0 manifold has slightly shorter length tubes and the DISA is larger again than the original 2.2 DISA, so there is some benefit to be had.

the reason I know all this?
I have a 2.8 twin vanos. I originally bought the M54B25 manifold thinking that was the actual 3.0 upgrade, not knowing at the time. (and also not having that pointed out by the seller either......)
The difference, after fitting it, was pronounced, and the car was brilliant after 4K revs with no noticeable difference in low end. I was well chuffed.
However once I became more knowledgeable about the upgrades, I realised it was not the M54B30 upgrade, so I always felt that it could be bettered
I finally got my hands on one of the M54B30 manifolds, and to be honest, after swapping it out, I did not notice much difference from the M54B25 version that I had already fitted (so 2.2 owners take note)


I have no experience of single vanos M50 upgrades, though I believe these give even more difference over standard..

I definitely have a 2.8 tu manifold at present but it has been ported out. I have a 3.0 to fit but not sure if it’s worth doing.

 

[gookah]

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[Slam]

Not even sure how it is possible to port it out other than maybe enlarging the hole for the bigger throttle body?
As you can see in the photos, one of the gains to be had, is by the changes of the profile from oval to full D- shaped Not sure how they could do this throughout the whole manifold if that profile is inside as well?

I wonder if the work they did was for the larger throttle body, maybe so that an adapter plate was not required?

The DISA socket can not be enlarged either, so it will still have the smallest DISA, and you wont be able to fit the 3.0 DISA in there...

I would be swapping the manifold just to see the difference in performance, and also to see what was done with the original

I have everything now needed to do the 3.0 manifold swap so I am very interested to see what they actually did for 1k. Portmyster who posted above you was the previous owner who had the work carried out has a lot more detail which hopefully he can pass on to me. Whatever they did though the car has a very strong top end and loads of low end torque still.

 

[gookah]

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