headers ???

[playero]

Hi there. I was just browsing in ebay and saw a set of headers for a e36/46 at a very reasonable price. It looks like they might fit my '95, 525i, they claim it will fit a M50 engine. Does anyone can confirm this for me?? I will like to get this if they will fit, even if I have to modify them slightly. TIA, Dave.

[DanDombrowski]

The consensus on those headers for the e36 people is that dyno results show no gain. I was considering them until I read that, then I stopped looking to find out if they would fit.

[winfred]

they are just not that different of the design from the stock cast manifolds, just a slightly different version of the usa e36 m3 manifolds, to make a difference you need something that's a tuned length header ("basket of snakes") so you get a scavaging effect from the exhaust pulses

[playero]

Thanks guys, I will invest the money then into something else.

[Kobe Diesel]

Playero, not to steal your thread, but Instead of making a new thread, I thought I'd post my question about exh headers. But to quickly answer your question, maybe my question about headers might interest you as an upgrade...

Is there any advantage to porting exh headers to match porting on cyl head?
Are the headers restrictive in this sense or sufficient for the design? And what about hi-temp coatings?

Asking b/c Im planning to embark on a significant performance upgrade on my M20 and I thought this can help.

TIA

[Bill R.]

larger than the port on the head and any port matching to be done has to be done to the exhaust port on the head itself. But yes port matching will a lways provide a small gain, High temp insulating coatings will help too since the better insulated the header is the better will scavenge exhaust since hot air moves faster than cold air. Its usually a trade off. Insulating wrap,spray on coatings such as jet hot etc will improve scavenging but they typically shorten the life of the header since it retains more heat this way, especially mild steel headers. To me the gain is worth the loss of useable life on the header.




Playero, not to steal your thread, but Instead of making a new thread, I thought I'd post my question about exh headers. But to quickly answer your question, maybe my question about headers might interest you as an upgrade...

Is there any advantage to porting exh headers to match porting on cyl head?
Are the headers restrictive in this sense or sufficient for the design? And what about hi-temp coatings?

Asking b/c Im planning to embark on a significant performance upgrade on my M20 and I thought this can help.

TIA