E46 M54b25 manifold conversion for 2.8 twin-vanos

Z3cade · Post by **Z3cade** » Wed 29 Sep, 2010 20:26

Hi guys i have just ordered an M54b25 inlet manifold with disa for a project to do one weekend over the winter...
I know from reading rubber-duckys thread that i will need the adapter plate also for the throttle body, which im in the throws of ordering....

I was just wondering if anyone else here has done this conversion and would they have any tips, info on the job?

The part im abit worried about is fitting the Throttle body as its not a straight fit?

Any help/ideas would be great, ta

w4tkins · Post by **w4tkins** » Wed 29 Sep, 2010 20:53

Hi this is what I wanted to do to my 2.0l but found out it doesnt fit

Here is the kit off ebay for the job. They sell fitting instructions and have a good website:

Bm conversions

Keep us upto date on your progress

w4tkins

yalden · Post by **yalden** » Wed 29 Sep, 2010 21:07

Watkins, that kit looks to be for the single-vanos varient of the 2.8, not for the M52TUB28 (twin vanos).

Z3cade, I believe the M54B25 or M54B30 inlet manifolds both have the larger ports so you should be fine there.

The inlet manifold should be a straight replacement for your existing one, however the throttle body will require an adapter plate (as sold by Turner Motorsport, which incidently should be available within the UK from Simpson Motorsport - 01594 841299).

Courtesy of Rubber-Ducky and the search facility

Rubber-Ducky wrote: The basic removal process is:

1) Remove airbox, MAF sensor and inlet piping.
2) Remove DISA, throttle body and idle control valve.
3) Unbolt fuel rail (4 x 10mm bolts) and pull it out with the injectors still attached.
4) Unbolt manifold (9 x 11mm nuts and 1 x 16mm nut under the throttle body).
5) Undo the various breather hoses in order to free the manifold from the engine.

Fitting the TB to the M54 manifold is a bit of a pain. I used the Turner Motorsport adapter plate, but I couldn't get the M52 TB to fit with it so I had to grind part of the TB down and mount it using only 2 diagonal bolts, keeping it orientated the same way as before. This provided sufficient clearance for the idle control valve.

You can see how much bigger the M54 manifold is compared to the M52TU one:

Here's the two DISAs (M52TU on the left, M54 on the right):

The halfway point:

M54 manifold with Turner Motorsports adapter plate fitted:

Throttle body with the corner ground down to provide sufficient clearance for the idle control valve:

Other than the mounting of the TB, fitting is the reverse of removal. I had to adjust the throttle cable slightly, but that only took a couple of minutes.

I'm really pleased with the results for 100 odd quid and imagine it will only get better as the ECU recalibrates itself over the next few outings.

Next step is a remap, I guess...

aceman · Post by **aceman** » Wed 29 Sep, 2010 21:15

I think Portymaster has done this conversion via CAutomotive including the remap. Maybe worth giving him a PM if he doesn't see this thread first.

PORTMYSTER · Post by **PORTMYSTER** » Wed 29 Sep, 2010 22:18

Hi Z3cade, I have had mine done with CA Automotive as Ace man mentioned but they did the work and I have no skills to do the work myself so I would not know what to mention on this. You could ring Roy at CA automotive as he may have an answere as he knows BMW's like the back of his hands. As my original manifold was machined and the butterfly on the T.body so the original parts joined back together.

I would say that once complete get the car remaped as this then makes everything work together and should bring the car to 230bhp and the responce and power is instant, just wish I had the schrink cams and valve springs done whilst the T.body and manifold was off and Roy said I would be looking at 250BHP and keep up to stock M's till 120mph.

Z3cade · Post by **Z3cade** » Wed 29 Sep, 2010 22:27

thanks guys yeah the throttle body only sounds like the fussy bit.
I will keep it up dated on when i give it ago

.......
Shouldnt be to bad.....

Any ideas of power/torque gains without a remap? it does seem abit restricted at high revs to me as standard and hopefuly this will free it up abit.

Z3cade · Post by **Z3cade** » Wed 29 Sep, 2010 22:33

PORTMYSTER wrote:Hi Z3cade, I have had mine done with CA Automotive as Ace man mentioned but they did the work and I have no skills to do the work myself so I would not know what to mention on this. You could ring Roy at CA automotive as he may have an answere as he knows BMW's like the back of his hands. As my original manifold was machined and the butterfly on the T.body so the original parts joined back together.

I would say that once complete get the car remaped as this then makes everything work together and should bring the car to 230bhp and the responce and power is instant, just wish I had the schrink cams and valve springs done whilst the T.body and manifold was off and Roy said I would be looking at 250BHP and keep up to stock M's till 120mph.

Thanks portmyster, if you dont mind me asking how much did it come to to have the original machiened and remaped?

w4tkins · Post by **w4tkins** » Wed 29 Sep, 2010 22:38

yalden wrote:Watkins, that kit looks to be for the single-vanos varient of the 2.8, not for the M52TUB28 (twin vanos).

Z3cade, I believe the M54B25 or M54B30 inlet manifolds both have the larger ports so you should be fine there.

The inlet manifold should be a straight replacement for your existing one, however the throttle body will require an adapter plate (as sold by Turner Motorsport, which incidently should be available within the UK from Simpson Motorsport - 01594 841299 begin_of_the_skype_highlighting 01594 841299 end_of_the_skype_highlighting.

Nice one Yalden :Thumb:

Does this mean our 2.0l can have this larger inlet madinfold fitted for extra bhp???? Also do you need a larger throttle body or your exitsting one?? You got me excited now.

Sorry z3cade for jumping in

PORTMYSTER · Post by **PORTMYSTER** » Wed 29 Sep, 2010 22:42

For all the lot around £1000 quit pricey I must admit but I felt I knew my car too much to sell and get the M// so my project continues to increase the performance. Exhust and simota all helps it to breath so worth investing if not already.

I would say that the rev limit is higher by an extra 500rpm and allows you to realy fly at the top end but still keep aload of torque its a guess as I have not a print out but stock is 205 so the torque will be 250 so real punch and on a previous run the gentleman who owned a TVR cerbra 4.4 was impressed by the way it went so I think you will be happy.

Z3cade · Post by **Z3cade** » Thu 30 Sep, 2010 19:16

Reading rubber duckys thread again am i right in thinking he didnt use the m50 adapter plate in the end??? as he says he used the plate but couldnt fit the t`body (with it) so does that mean he just grinded the t`body to clear the idle valve so he could use two of the original holes to mount it?? he also says doing this aloud for the t`body to sit square (oriented)
As if you mount it with the plate it would be off square as the holes are at an angle........

Im confused.... I just need to know as i dont want to order the adapter plate if i dont need it.....

Is rubber ducky still on here?? as id like to ask him a few questions i think

yalden · Post by **yalden** » Thu 30 Sep, 2010 21:43

Ok, I've done some research...

You don't need an adapter for the manifold to fit the engine, the M50 manifold adapter is there for the single-vanos conversions, not dual-vanos.

Because you have an M54 2.5 inlet manifold you can't effectively use the Simpson Motorsport adapter to bolt the throttle body onto the manifold - you'll have the same issues as Rubber Ducky experienced.

The adapter is made to suit the 3.0 inlet manifold, which shares the same inlet design but has a different throttle body mounting point - because the 2.2/2.5 and 3.0 M54 engines use different throttle bodies!

Based on this you can either sell your 2.5 inlet and buy a 3.0 inlet and the adapter, or take your 2.5 inlet manifold and original throttle body to a specialist machining outlet and get them to fabricate the relevant adapter, which should be straight forward.

w4tkins wrote:Does this mean our 2.0l can have this larger inlet madinfold fitted for extra bhp???? Also do you need a larger throttle body or your exitsting one?? You got me excited now.

Yes mate, I'm tempted to give it a go for the punt of £100! Our TB is the same size as a 2.8 so should be ok, I'm not aware of any available upgrades but I'm sure you could get it bored out and a new butterfly machined if you wanted!

As per my above comments, the easiest solution is to get a 3.0 inlet manifold and the adapter, but we could get the inlet from a 2.2/2.5 M54 and cusom fabricate an adapter!

Z3cade · Post by **Z3cade** » Fri 01 Oct, 2010 08:08

yalden wrote:Ok, I've done some research...

You don't need an adapter for the manifold to fit the engine, the M50 manifold adapter is there for the single-vanos conversions, not dual-vanos.

Because you have an M54 2.5 inlet manifold you can't effectively use the Simpson Motorsport adapter to bolt the throttle body onto the manifold - you'll have the same issues as Rubber Ducky experienced.

The adapter is made to suit the 3.0 inlet manifold, which shares the same inlet design but has a different throttle body mounting point - because the 2.2/2.5 and 3.0 M54 engines use different throttle bodies!

Based on this you can either sell your 2.5 inlet and buy a 3.0 inlet and the adapter, or take your 2.5 inlet manifold and original throttle body to a specialist machining outlet and get them to fabricate the relevant adapter, which should be straight forward.

Thanks Yalden

Right i think the only solution is to either do the same as rubber ducky and grind part of the throttle body and mount it only using two screws, using the adapter plate OR Like you say try and get a custom adapter plate made up for my M52tu throttle body to fit the 2.5 inlet manifold.

I dont think selling the M54b25 manifold and replacing it with a M54b30 manifold would remedy the solution as i would still have the same problem. Trying to mount the M52tu throttle body to the adapter plate...

I wish i could get hold of a M52tu throttle body as it would save having to take my car to bits to try and get a plate made up....

yalden · Post by **yalden** » Fri 01 Oct, 2010 20:51

The 3.0 manifold has a different throttle body mount which I assume would suit the adapter as this is the intended application!

Z3cade · Post by **Z3cade** » Tue 02 Nov, 2010 22:39

Right i am currently at the half way point now with the inlet manifold off and ive changed all the pipes and bits from the 2.8 manifold to the m54 325 inlet manifold..
I should have the tuner motorsport adaptor tomorrow as simpson motor sport only got it in in today!! Been waiting weeks for it!!

If the postman decides to be nice and it comes through the letterbox tomorrow then i will fit the throttle body and get the manifold back on in the evening!!! Cant wait to find out what differents its going to make!!!!

CP00black · Post by **CP00black** » Tue 02 Nov, 2010 23:17

yalden wrote:Ok, I've done some research...

w4tkins wrote:Does this mean our 2.0l can have this larger inlet madinfold fitted for extra bhp???? Also do you need a larger throttle body or your exitsting one?? You got me excited now.
Yes mate, I'm tempted to give it a go for the punt of £100! Our TB is the same size as a 2.8 so should be ok, I'm not aware of any available upgrades but I'm sure you could get it bored out and a new butterfly machined if you wanted!

As per my above comments, the easiest solution is to get a 3.0 inlet manifold and the adapter, but we could get the inlet from a 2.2/2.5 M54 and cusom fabricate an adapter!

Im very much interrested. Have anyone tried this on a 2.0? If so what could one expect? Im guessing one should do air/exhaust and finally a remap with this mod? I really would appreciate some "guestimates" on gains..

..Im not very skilled but could probably manage this by myself. Not sure its worth it though? Id be happy if it reaches somewhere between 2.2 and 2.8 figures (170-192).

-P

Z3cade · Post by **Z3cade** » Tue 02 Nov, 2010 23:33

Im not 100% but i think it can be done for the 2.0 with the same parts?..
Maybe someone should try it!?
Should think you`ll see 10-15bhp increase, but more with a remap.

Just to add the parts are now more expensive than when rubber ducky did the mod.....

Z3cade · Post by **Z3cade** » Wed 03 Nov, 2010 19:13

Right its all done!!

You can tell the car can breath alot easyer now, wow....
Seems to pull very well at high revs 3500rpm +
Low end pull hasent changed from what i can tell but i guess with a remap
it will be much smoother and pull harder.

I would recomend the mod but just to warn you it can be very fiddly....

Tori · Post by **Tori** » Wed 03 Nov, 2010 20:32

Z3cade wrote:Right its all done!!

You can tell the car can breath alot easyer now, wow....
Seems to pull very well at high revs 3500rpm +
Low end pull hasent changed from what i can tell but i guess with a remap
it will be much smoother and pull harder.

I would recomend the mod but just to warn you it can be very fiddly....

To get the most from this add an exhaust and a induction kit, if you want to go the whole hog add a sports cat before you do a remap

Z3cade · Post by **Z3cade** » Thu 04 Nov, 2010 19:19

Tori wrote:
Z3cade wrote:Right its all done!!

You can tell the car can breath alot easyer now, wow....
Seems to pull very well at high revs 3500rpm +
Low end pull hasent changed from what i can tell but i guess with a remap
it will be much smoother and pull harder.

I would recomend the mod but just to warn you it can be very fiddly....
To get the most from this add an exhaust and a induction kit, if you want to go the whole hog add a sports cat before you do a remap

Id love to but funds are an issue at the min....
Ive already done the cold air feed mod to the standard airbox and also have a knn pannel filter fitted, which now with the M54 manifold the induction noise has increased! sucking more air i guess....
Not sure on an exhaust system as i dont like the boom in the car when driving....
I would consider a decat pipe if there is such a thing for the 2.8??