Bmw M50 Headers

[cwbaader]

Intro, my name is Chuck and I am building an E36 for SCCA racing. I have used PipeMax in the past, but don't have a motor apart. Has anyone run PipeMax on the stock M50/S50 motor that can share numbers? Thanks

[mag2555]

Is every E36 built for SCCA racing built the same (i.e.) I think folks who might help you need some motor details, no?

[cwbaader]

Yes. SCCA class I intend to run is ITR, which dictates a 2.5L motor with stock cams.

[digger]

its $75 worth the $$$

[Hairyscreech]

A lot of the relevant infonis the same as the m20. Bore, stroke, etc cams are quite mild but the spec is on the internet, valve sizes are also out there, I don't have the info to hand but have looked it all up in the past. Google will give you all you need.

Are you looking at non-vanos or later m50tu lumps?

[cwbaader]

I quite successfully ran a set on my 325e motor and assumed the lengths to be similar. But this is a single vanos TU motor with vastly different intake and exhaust volumes that is why I was wondering if anyone had actually measured the motor and run the numbers. I've seen the Burns header, but (I assume due to packaging) there is no collector after the 3 to 1 merge. That is where I was able to make the most gains with my M20.

[digger]

I quite successfully ran a set on my 325e motor and assumed the lengths to be similar. But this is a single vanos TU motor with vastly different intake and exhaust volumes that is why I was wondering if anyone had actually measured the motor and run the numbers. I've seen the Burns header, but (I assume due to packaging) there is no collector after the 3 to 1 merge. That is where I was able to make the most gains with my M20.

in simplistic terms the primary length and collector length is mostly dictated by the rpm of peak hp, the pipe size is dictated by the amount of peak power.

i dont think these would be the same on a low rpm and low hp 325e so i would not assume it will be similar

[Hairyscreech]

Just noticed you were reffering to the m20 eta lump, certainly ignore that as a base line, I was referring to the m20b25 i motor when I said they are not too dissimilar to the m20 numbers
The primary length on the m50tu is about 320-330mm, its tuned for about 6000 rpm when you include the port length(working from the top of my head, can go back and check numbers if needed), the intake is about 45mm diameter if it were a round tube.

The exhaust lengths needed are as digger says dictated more by the desired rpm than anything else, a stock cammed m50tu is aimed at peak power around 6000rpm so the lengths are very similar to the m20 stuff aimed at similar rpm.

Power wise the m50tu is only 193hp, about 15 more than the m20, it is another underachiever in stock form and the VE is not drastically different around peak power.
The key to the m5x engines being better is greater area under the curve.
I can go and dig my data out later this week but if I remember right the ideal pipe diameter pipemax spat out was about half a pipe size up from the m20. (As in between 1-1/2" pipe and 1-3/4" pipe for example, not +1/2 the pipe diameter).

I have actually measured all this and run the numbers months back, still have a bare m50 head in the shed, I will have to dig out the numbers as I haven't looked at anything of that sort for months.
Otherwise as noted, the bore, stroke, firing order, cam durations, valve sizes, VE and port lengths are all out there on the internet and they are accurate within sensible margins of error.

[cwbaader]

Actually have built several m20 motors, for ITS, and for ITA. MAX RPM For the S motor is about 6800. For the A, 5600 They made 180 and 155 on a dyno jet. Don't remember the torque on the S, but the A made 180.

[digger]

Just noticed you were reffering to the m20 eta lump, certainly ignore that as a base line, I was referring to the m20b25 i motor when I said they are not too dissimilar to the m20 numbers
The primary length on the m50tu is about 320-330mm, its tuned for about 6000 rpm when you include the port length(working from the top of my head, can go back and check numbers if needed), the intake is about 45mm diameter if it were a round tube.

The exhaust lengths needed are as digger says dictated more by the desired rpm than anything else, a stock cammed m50tu is aimed at peak power around 6000rpm so the lengths are very similar to the m20 stuff aimed at similar rpm.

Power wise the m50tu is only 193hp, about 15 more than the m20, it is another underachiever in stock form and the VE is not drastically different around peak power.
The key to the m5x engines being better is greater area under the curve.
I can go and dig my data out later this week but if I remember right the ideal pipe diameter pipemax spat out was about half a pipe size up from the m20. (As in between 1-1/2" pipe and 1-3/4" pipe for example, not +1/2 the pipe diameter).

I have actually measured all this and run the numbers months back, still have a bare m50 head in the shed, I will have to dig out the numbers as I haven't looked at anything of that sort for months.
Otherwise as noted, the bore, stroke, firing order, cam durations, valve sizes, VE and port lengths are all out there on the internet and they are accurate within sensible margins of error.

for 6000rpm youd be wanting about 750-800mm primary off top of my head according to pipemax, collector will be probably be circa 450,900 or 1800mm depending on which harmoinc you choose

[cwbaader]

Actually used two collectors on same headers both motors. 33 x 1.5 priamarys. Used Jere Stahl headers and the two pipes were not equal under the car. So I used a 9" and a 18" x 2 3/8" collectors to a merge and out the side of the car with 3" oval. Excellent power band.
For m50tu I wonder???

[digger]

post up the particulars of it,

bore, stroke, CR, rod, peak hp rpm , valve sizes, cam duration and lift ICL and LSA at the topend part of the curve with vanos ret inlet or whatever it does and the hp and tq

[digger]

guessed a few inputs should be close

[digger]

one thing is that the more duration the longer the length predicted (2" longer primary per 20* extra duration), and the slighty smaller the pipe size....

[Hairyscreech]

Had 5 mins while at work.

Valve size:
Intake - 33.00mm Head Diameter, 5.97mm Stem Diameter, 106.10mm Length
Exhaust - 30.50mm Head Diameter, 5.96mm Stem Diameter, 105.65mm Length

CR:
10:1

Cam specs:
in 228*, 9.0mm; exh 228*, 9.0mm
Lobe centre is 101 degrees.
Vanos throws a big question mark as it moves the centre line 12 degrees.
Going to be a guess at the .050 duration and the lash.

Inlet port is 53x30mm IIRC.
Port lengths are about 95mm



The rest of the short block dimensions are the same as the M20.