M50 vs M52 intake flow comparison

[freerider]

I found this very interesting.

http://www.bmw-m.net/techdata/m50vsm52.htm

I put the M52 intake manifold on the flowbench today. Below are the results and the previous numbers I got from an M50 intake. All measurements were made on the 300cfm scale and at 28" of water. The unused runners were blocked off, so the numbers represent the flow from the throttle body opening to the port face.

..............M50..........M52
cyl 1.....284cfm.....188cfm
cyl 2.....276cfm.....191cfm
cyl 3.....288cfm.....201cfm
cyl 4.....288cfm.....195cfm
cyl 5.....276cfm.....194cfm
cyl 6.....284cfm.....191cfm

M52 left and M50 right port opening size comparison. The max. dimensions for the M52 is
45mm x 23mm. The M50 is
55mm x 25mm.

I will post my dyno graph from yesterday and you can clearly see how the car chokes at higher rpm with the restrictive intake.

 

[moranor@axis]

for some reason i stumbled upon this same thread the other day... i cant even remember what i was looking for, but i remember thinking why would they put such a rubbish manifold on the 328i...

 

[freerider]

for some reason i stumbled upon this same thread the other day... i cant even remember what i was looking for, but i remember thinking why would they put such a rubbish manifold on the 328i...

It was done to restrict output and for emissions controls, same reason there's a baffle in the airbox.

 

[Diablo Jnr]

All the 2.8 german cars of the time made more or less the same power because of emmision laws of the time, so the 328i had to be pegged back

 

[moranor@axis]

damn the marketers...

 

[freerider]

Here you can see just how bad the intake chokes the engine after 5000rpm

 

[moranor@axis]

the drop in torque is quite drastic... after 5k

 

[freerider]

Yeah, you can feel the power just falls away after 5k when you driving.

 

[LPM320]

Hi guys.

While on this subject, i recently bought a m50 intake for my 328i, what i basically need to know, is it a bolt off-bolt on mod? Is remapping absolutely neccessary after doing this mod?

I also got the m50 throttle body with this manifold, do i use this throttle body, or the existing 328i throttle body?


Thanks

 

[Diablo Jnr]

Yep, low down, the 328i pulls really well but as the graph shows, it dies at top end. With the M50 manifold, my car only starts pulling around 4000rpm and just gets stronger from their, not ideal if its your daily run around though

 

[freerider]

Hi guys.

While on this subject, i recently bought a m50 intake for my 328i, what i basically need to know, is it a bolt off-bolt on mod? Is remapping absolutely neccessary after doing this mod?

I also got the m50 throttle body with this manifold, do i use this throttle body, or the existing 328i throttle body?


Thanks

You will need to either fabricate some parts, or purchase something like this http://www.turnermotorsport.com/p-1...it-to-install-obdi-manifold-on-an-m52s52.aspx

You are also going to use your existing throttle body.

 

[Bayn46]

Nice find. I definitely feel a very abrupt power kill at the top end which is why I barely bother revving it that high. Nice to know why.

I'm guessing there would be a bit of a sacrifice down low though but would it be enough to make the top-end gain worthless :thinking:

 

[Raybimmer]

How often do I drive at 5000 rpm daily ? If torque was the same with M50 manifold then ok , but I do not see reason to spend Saturday swopping manifolds- then my 325i will be similar to a 323i .

 

[moranor@axis]

the whole point of having a petrol car is it wants you to rev it... otherwise you may as well get a diesel :Zzz:

 

[freerider]

I dont think there is a day that goes by that the rev needle doesnt visit the red on my cars.

Its always been like that and it will more than likely always stay like that

 

[LPM320]

Thanks for the advice guys...

Freerider: You say that parts have to be fabricated, do all parts listed in the tms package have to be fabricated , or only certain parts?

 

[freerider]

Thanks for the advice guys...

Freerider: You say that parts have to be fabricated, do all parts listed in the tms package have to be fabricated , or only certain parts?

you just need to modify the fuel rail mounting brackets and then there is some plumbing that needs to be dont wrt pipes and fittings under the intake. I just prefer to keep things looking neat and organised, and also want to avoid vacuum leaks etc, so will rather go with the kit, and avoid a hack job looking finish.

 

[Raybimmer]

As a daily drive I prefer torque and thats why the 328i is better than the 325i .The red line is addictive , find the 328i runs to just over 60 in first , 100 in second , but the rush from 50 to 90 in second is awesome . Maybe someone needs to import and then get measurements and then we can make kits up locally . Anybody done any testing of on the road performance - acceleration to certain speeds and the overtaking acceleration ?
Maybe fitting the 3.46 diff and intake manifold from my 325i will do , that thing revs quickly , but runs about 185km/h at 5000 in 5th , has run to limiter in 5th .

 

[Major]

Just keep in mind that people report a drop-off in torque in the everyday driving RPM range with the M50 swap and nothing else. It's great on top, but if you don't have a heavy foot you'll feel a loss. You should get a remap.

 

[sclass]

My 328i Coupe is such a joy in town/traffic,press and go!It would be even better with manual 'box (auto box is to fussy). Almost no point revving to 6k RPM (let alone 6.2k redline). My daily commute to work is a 7km freeway drive and stop/go traffic once in town, and I never need to hit 3 RPM!I'm between 1.5k and 3k for 90% of the time so the M52's torque characteristics are perfect...most of the time!When I want to drive it like I stole it I do feel a little let down...I personally won't do the M50 swap,I'd rather to mods that'll give me more of the same.Decat,exhaust,cold air intake (is it worth it?). I'd rather not be revving the rings off a 15year old engine, but that's just my preference. I fully understand why someone would want to do the swap though.