SSI's or Headers? Cost/Performance Analysis.
 

time to remove my rusty 22 year old heat exchangers from my 83sc.

should i do SSI's or Headers?

I dont care too much about having heat, this will be a summer car, anyway.

what are the cost/performance aspects of one versus the other? thanks

Remember that heat may be an issue to someone else if you ever decide to sell the car. SSI's are very popular. I personally like the B&B system that I have since I get the benefit of headers and heat (but I changed the chip to adapt to the more open system).

The world is a very cold place...

With stock port size for a 3.0, the SSI's will make the same power as headers. (more or less)

You never know when you're going to want heat. Even on a track car it can be necessary sometimes.

Heat is nice. You never know if you'll want to take the car out for a spin in the winter or turn on the heat when the race track is cold.

I think headers give you a weight savings over SSIs. I have no idea what the difference is though. Does anyone know? Tyson? It would be nice to lose some weight in the rear of the car. Also I know with SSI's you have to change some oil lines. I don't know if that is also necessary with headers.

Correct me if I am wrong, but aren't SSI headers too? The definition of headers in my book is that there are steel tubes for every exhaust port vs. a single cast iron manifold, even if the cast manifold would have split runners. What you probably mean is the difference between racing headers with no heat and SSI with heat?

I doubt there is any increase in power over the SSI by going with headers. The price difference is not very much either. If you look around, you can find SSI used. I did in only a couple of months of looking.

George

It was a toss up because I have been told by loacal racers and shop owners that headers without exchangers do make a bit more power and they weigh less.

I decided on SSI's.

- They hold their value very well. It's not a big risk if for some reason you decide to sell later

- Even if it's 50 degrees out spending more than 60 minutes in the car without heat can be uncomfortable especially for a passenger.

- There have been plenty of times when I needed to defog the windshield, especially at the track. Header owners are sitting in the paddock and people with heat exchangers are out on the track.

From what I remember, headers are defined as equal length tubing for each exhaust port combined into a single collector. Which is what any stock heat exchanger is. Take them apart and you will see that there are three equal length tubes combined into one collector. Now, a header (without a heat exchanger shroud) does allows better cooling of each tube which will scavenge the exhaust better. Am I right here?

Anyone have dyno results before and after SSI or headers????

On the std mild steel heat exchangers (& many/most of the stainless steel versions) the primary pipes are not quite equal lengths.

Those on genuine SSI's are.

SSI's. More versatile, same performance. I have em'. I have heat too...

I'm in california, and have to smog test my '82 forever. I need to be able to switch back to the stock heat exchangers with a CAT every every two years for the smog test. If I put SSIs on my car, and backdate the oil lines so they will fit, can I put the original heat exchangers, CAT and muffler back on without going back to the stock oil lines?

Uh... have you guys running illegal (no-cat) exhaust sytems relaized that they have mobile sniffers deployed now? They can set up a trailer next to an exit ramp and it takes a pic of your car and license plate as you go past and wraps that up in a nice little bundle of evidence with the pollution record from the sniffer for prosecution.

Any ideas what they will do to you if they catch you deliberately breaking the law? I don't know what the penalty is, but they are likely to get mighty harsh....

I'm not worried about the lack of a cat on my 3.2 w/SSI's.

That's the nice thing about stuffing it into a '73.

Except for the cooling. Usually people coat headers or wrap them in insulation to keep the heat in. Higher temps in the exhaust increase flow - is the theory at least. We had recently discussed a similar topic... http://forums.pelicanparts.com/porsche-911-technical-forum/205189-ssi-heater-box-inlets-ok-leave-open.html

Cheers, George

No. You will need to convert it all back.

George

First of all, we certainly do not run these cars on the street, so there is nothing illegal here. We trailer and run these cars on the track. There is no smog laws on the track. Have you ever rund in the rain in December? You want heat, hence SSI.

But let's theorize here. What happens if you drive with a car that emits too much? If "they" really have a trailer set up there, they will send you a letter, that your car is out of spec and that you please have it smogged. I have yet to hear from anyone that they have started to do that on the onramps. I really doubt that the technology is there. How would you measure concentration of certain gases coming out of a tail pipe on a car that drives by at 30+ mph? The testing that's been done here is more about scaring people at this point. They may be able to pick up cars that are grossly polluting. Not the case with any well tuned 911, cat or not.

The only thing that exists and goes into the direction of the above sniffer trailer is a 1800 number where people can call the DMV and report cars that smoke. I know someone that had an older Porsche with worn valve guides that would sporadically blow some blue smoke in city traffic. He got reported. He got a letter from the DMV which notified him that his car may have a problem, advising him to have it checked out.

What is more practical than remote sensing, is trailers with a dyno and a sniffer on it. "They" pull you over, and test your car right there. There is potential for trouble. However, with bieannual smog checks, why would they bother. Especially since they would have to pay for the tests, not you. This state is broke. There is no worries that they can come up with the money, unless there is indication that there is huge populations of people that pull and re-install smog equipment every 2 years. I doubt that's the case.

George

"Remember that heat may be an issue to someone else if you ever decide to sell the car. " - Por_sha911 -

Typical, say something but contribute nothing! Another Pelican who knows little
but what polish to use.

pound sand.