Headers - I know nothing!
 

I have been thinking of getting a set of headers for my 78SC for a couple of reasons.

1. The extra power would be nice
2. I've removed the heater & have no need for the heat exchangers, so was thinking a set of headers would allow for better air flow around the bottom of the engine and hence better engine cooling. Is this a correct deduction?

The car is for street use only, so I'd need some that will give a power bonus & won't overly terrorize the neighbours.

I don't think I necessarily need stainless as corrosion not so much of an issue, but not opposed to SS either, cost is more of a factor than bling.

I'm thinking I'd retain my standard 2 in, 1 out 3.0L muffler - do I lose the power benefit from doing this?

Any advice on a suitable set would be greatly appreciated

RarlyL8 Motorsports

Brian is well known and respected on this board and Pelican carries many of his products . . .

If you love sound I think you'll be happier with a matching 2/1 sport muffler. Doesn't have to be expensive - a fabricated Dynomax or Magnaflow will do.

My headers work best on modified engines. For a stock engine the least expensive option would be backdating to pre '74 and removing the exchangers. Lots of cheap Asian products out there as well.

^ out of curiousity how do the exchangers effect exhaust flow/noise? thinking of removing mine

Are there any benefits to heat exchangers other than heat?

emmissions

Could someone be more specific and suggest a setup, headers and muffler for those of us that are not hard core track guys and are building street cars that cant be too loud but like the sound and the perf benefits.

I'm probably partial... SSI + M&K 2/1. Not too loud and still sounds like a Porsche.

What every you buy, dont buy OBX. My headers were cheap... and they cracked at the welds in 5 months and 2 track days. I got no refund and no service.

BTW, your current muffler, 2 in 1 out, suggests that you already have a non stock exhaust. SC's came with 1 in 1 out with cross over pipe between the heat exchangers. So what is it you have now?

I initially took the stock heat exchanger sheet metal off the pipes and had 'factory' headers ;) Engine running temps dropped ~10 deg. F.

There are 2 kinds of headers: short and long. Shorts end right after the collector and you can mount megaphones to them. You can make short headers into long headers by adding extensions. Long headers and short headers usually have the standard 2 bolt flange and will accept a multitude of aftermarket mufflers. The exceptions are B&B and Triflow setups that use their own flange types. If you buy one of their setups you will be stuck with their muffler or be visiting a muffler shop to modify.

LONG Headers (pic courtesy of : kt911rs):
http://forums.pelicanparts.com/uploa...1317688271.jpg

SHORT (courtesy of:Parts junkie):
http://forums.pelicanparts.com/uploa...1316875060.jpg

Custom setup (courtesy of JB). Note the 4 bolt flanges on the right hand side allow fitment to all air cooled 911s 66-97:
http://forums.pelicanparts.com/uploa...1314739673.jpg

SHORTS with extensions (courtesy of Randy W):
http://forums.pelicanparts.com/uploa...1310588932.jpg

As for sizing it depends on the purpose of the car. For a 3.0 stock street engine you should be looking at 1 5/8" headers. That is the diameter of the pipe that attaches to the exhaust port. Standard sizes are 1 1/2", 1 5/8", 1 3/4". Bigger the motor bigger the header. Your stock 3.0 can get away fine with 1 1/2" for a street application as well.

As for material most are mild steel. Some will also come in stainless. Really expensive custom sets can be made in Titanium. Its a very ugly environment down there so they do take a beating. I might consider having the set jet hot coated, but there are different opinions on that. Most agree that wrapping them is not a good idea for longevity. Most 'header' paint I have used has failed miserably on track so I don't bother anymore. The stainless will turn color so don't expect them to be all shiny and new for long.

that about covers it...

best regards,

Michael

IRL: As for noise levels that is controlled by the muffler and not the headers. Sure there is a small noise increase with the headers, but the overwhelming contributor is the muffler. There are many muffler makers here that make great products that fit your Porsche perfect. There are also several DIY attempts and successes that can be found in the searches. Most muffler threads have some kind of YouTube sound clip that you can listen to.

My personal preference is M&K. Excellent quality and service. Also it cuts your muffler weight back there down by about 50%. The sound is great, but I lean to the noisier sound side being a track oriented fellow. There are a few exhaust clip collection threads that you can find and listen to lots of various setups.

And don't rely fully on You Tube. Actual sound is much louder than the video. Here's my GHL muffler (2/1) which sounded great in the video but was unbearable in actual (loud + droning like crazy). Do a search... plenty of info here on the subject.

PORSCHE 911 3.2 w/ SSI GHL - YouTube

Dug up the old OBX is crap thread ;)

http://forums.pelicanparts.com/porsche-911-technical-forum/509747-obx-headers-cracked-apart.html

-m

Having looked at the several pix of cracked headers...the most common cause is bad welds...not enough penetration.
But....I can remember making headers for various engines over the course of many years...and the hardest thing when constructing them was to get the ends of the pipes to come together without any side deflection.
The closer to a perfect match, the better.
During the heat/cool cycles, and deflection before welding is amplified and puts extra strain on the welded pieces.
This is why you spend the money for quality parts.
Bob

Many thanks for the comments guys.

The idea of removing the heat exchanger part of the existing exhaust is interesting, the reduced running temp would seem worthwhile (no power boost though :( , but I'm intimidated by the fear of breaking studs in the removal process, so would probably replace with new rather than adapt existing so I would have to re-do in the near future.

I'll do a search on back dating the system to pre-74 and see what I can find.

Hadn't appreciated that there may be a weight advantage also, it is my intention to put my SC on a diet and every little helps.

Thanks again

Actually, Glen, when I removed my heat exchanger metal I left them connected to the car. I used a cutoff wheel, tin snips, a drill, and a dremel with small cut-off wheel. Took a bit of time and for sure would be much easier with the whole system off the car, but it was done in 1/2 an afternoon. Sure made it easier to take the whole system off later, though!

-Michael

You can also look at George's European headers, very good quality and proven results.