Oppinion is needed m88/3 headers vs s38-b38 thanks - The Unofficial BMW M5 Messageboard (m5board.com)

First e28 M5 · 6th April 2009, 09:55

Hello guys,
I am working on my project E30 M3 with 3.8 swap with 6 speed trany.

My question is:
Since S38 B38 has smog pump and meets the World Emission Standards I am sure that the Headers are design to work with that. Means on other hand that they are redused performance wise?

If I get M88/3 Headers wich are made to work with no cats means real BMW Motorsport Headers and put them on S38 B38 will I get some few extra Hp or the 3.8 are design to work best ???

Please give your oppinion.

Thanks
Anri
www.EuroClassicMotors.com

Ferrari-Bmw · 6th April 2009, 22:48

I am no expert but i have heard that B38 headers are designed for S38B38 engine,, and therefore the M88/3 header are not so good ,, because of sound pulse and other technical detail..

but i could be wrong

The M88/3 header are pure art,,,,, (( the M88 M1 header are stunning

))

roortube · 7th April 2009, 00:31

I'm no expert either, but the boys at M Gmbh are...they used the B38 headers on the B38, so I'd do the same. If you're now using an air pump and are concerned with possible restriction it should be easy enough to remove the ports in the header runners and smooth over them.

MM-5 · 7th April 2009, 09:18

The cylinderhead exhaust flow is 85% from inlet flow in S38B38, so it is a little too big compared to natural aspirated engine needs (70-75%). The primary pipes diameter in S38B38 headers are not very big, but big enough for most natural aspirated S38B38 engines with powerlevels below 400 hp. But the airpump airpipes restrict the exhaust flow and can be cut off if airpump is not needed.

I think the manufacturer has put those airpipes and quite little primaries and secondaries for reason (to get better balance for exhaust vs. inlet flow).

The S38B38 secondary pipes are very little and this engine benefits from bigger secondary pipes when modified. My own S38B38 headers are going to be modified so that secondary pipes are 2,5" (63,5 mm) outer diameter with original primary pipes.

The smaller the primaries and secondaries the better torque and power at lower and midrange rpm levels. This is one reason why manufacturers make little smaller exhaust pipe diameter than optimum for high rpm power. It´s usually better to use too little exhaust pipes than too big. Then You only lose little top end power and not the broad torque curve.

I would need maybe those M88/3 headers because I´m going to use nitrous oxide in my engine. But I first try with these modified S38B38 headers. Nitrous oxide enhanced power needs much bigger and better exhaust flow, because the engine burns much more fuel.

Best Regards, Janne.

First e28 M5 · 7th April 2009, 16:52

I agree we are not smarter than the creators from BMW Motorsport GmbH !

I am asking like a upgrade because of the World Emission Standards. For example my E24 M6 is 1988 and its S38 B35 not M88/3 so the headers are those stupid regular headers I will change it soon with M88/3 for good and its going to be upgrade. Next example on S38 B36 its very popular to put cam gear from B38 3.8 and hop up the engine with litle bit.

So since there allways small upgrade to hop up these nice engines. Still I need more oppinions if M88/3 are slightly better than B38 ? or they are the designed to work best.

Thanks
Anri
www.EuroClassicMotors.com

MM-5 · 8th April 2009, 07:40

If your engine is stock or nearly stock I would fit S38B38 headers without the airpump airpipes if they are not needed. It´s better compromise and You get wider torque curve. If You need more high rpm power, then use M88/3 headers if they have those 48 mm primaries.

But the choice is yours and this is only my advice.

Best regards, Janne.