Best exhaust system for an 80 SC - for fast road use

[stv951]

I know there are many posts on this subject, but i guess there might be some new solutions. I also reckon that there should be interest in one thread with as many experiences as possible. We have a 911 SC 80 MY US spec, catalyst equipped. Car has the original exhaust and heat exchangers, which are all now pretty rusted. We are interested in a complete SS system that would gain us some power, and probably keep a cat+O2 sensor. Car is mainly used on the street for trips and curvy roads. Sound should be throaty, but not excessive, as we also travel with it and want to be w/o headaches !!!
I know about SSI, M&K, Dansk etc. What do you guys recommend ? Are there any sound clips for refference ?

[stv951]

Also, which are the best headers for an otherwise stock engine that would give more torque ?

[Brother]

Do you have to pass emissions tests?

SSI's and a dansk or MK exhaust. Single out of the muffler if you want it quiet or dual out if you can tolerate a little more noise.

[stv951]

No, we dont have to pass smog tests here. Is there a big difference in performance with and w/o cat ?
SSI heats exchangers is the way to go ?

[DanielDudley]

Like wine, you have to pull the cork out of an SC.

SSIs are the best. Dual outlet mufflers can be really, really loud and obnoxious at low engine speeds, when you would like a quiet cruise. A serious drone. Just pulling the cat doesn't cut it either.

You need scavenging to really get the benefits from an SC, unlike a Carrera, where you can just pull the cat.

Yes, you will feel the difference. It is a nice upgrade, and worth doing if you can afford it. Make sure the distributor is operating correctly, and is not binding on the advance.

There are lots of threads about SSIs, distributors, mufflers and etc, that you can access by using the search function. Cams are nice too, and they will get you about a far as you can take a stock engine without a rebuild, with the exhaust.

You will notice the difference.

Don't over think it. If a bit more snap would make you happy, do it.

[Oh Haha]

Here are a ton of clips to enjoy.

The ultimate exhaust sound clip thread!

[mb911]

I would suggest ssi's with a nice 2 in 1 out you will not be disappointed and will work fine for your needs

[carlosR]

I've got the 2 in 1 SSI's on my 77 2.7L and it sounds great and is plenty "zippy".

[RWebb]

there are no new "solutions"

you do not have a cat on an SC (do you?)

use SSIs, unless you live in a hot area and never need heat - not even to clear fog/condensation off the windshield. if the latter, get some headers to save wt. - they do not flow any better than SSIs as the latter are just a heat exchanger built around headers in quality stainless...

the extra hp will be limited unless you:
- replace the cams, induction system, and pistons - might as well clean up the ports and flow the heads; twin plug and boost compression, do a spark search.... then you will get close to what a NA 911 motor of 3L can do.

there is no cheap magic out there.

next step = turbo

For a muffler, I'd either replicate the factory unit or for more noise get a Monty (lots of data on performance) or Ben's M&K (less expensive I think, but with few data on performance)

many aftermarket mufflers HARM performance but the Monty is safe and the M&K should be safe

did I say there was no cheap magic?

[911Freak]

FWIW
After a lot of research and observing other SC's I went with BB 2 in 1 out

I have a cat in addition to a Euro pre-muffler (cat bypass)

When using the cat & BB I noticed a slight improvement over stock..

However when I use the BB & cat by pass (Euro pre-muffler) I noticed a bit more throttle response and my butt dyno thinks I've got more power

Neither of these set-ups are too loud or create obnoxious cabin noise.

The next steps are Cams and SSI's
Then full on top-end (P&C's, Cams, toss out the CIS)

Happy hunting!

[Ferraripete]

borla may no longer exist but, if you can find one for sale on the classified list...get it!

years ago i had a factory turbo look. i put a borla on the car and to this day, i have never heard a better sounding 3.2! the quality was not great nor was the customer service (thus the company exit) but the sound from the 3" single outlet was incredible!!!!

best,

pcb

[stv951]

Thanks guys,
Summing it all up, I guess its a straght forward way. As I was expecting, SSI heat exchangers are the way to go (pelican part number SSI-911-30L). Then, after reading many good points on M&K rear silencer 2 in 1 out, I will also choose this one for its sound and value.
What else is needed for a complete exhaust upgrade ? Hardware bits, oil lines etc. that might not be included ?

[FinallyGotOne]

I went with 74 911 OEM headers and Exhaust and the power difference is for sure noticable!
And I kept my heater and defroster this way,-glad I did!
Lines needed to be moved about/removed.

My 79 sounds really good, but not too loud, and runs very strong.

For gaining quickness- Lighten the car up before you do anything, check into different gearing. Any thing beyond that is $9,000 plus!

[SpeedracerIndy]

When I got my car it had stock headers, cat and Bursch 1 in 1 out muffler. It sounded great, just a little louder than stock. The I swapped the cat for a euro pre-muffler with the bursch exhaust. That was a slight kick in the pants, but not huge and it was slightly louder. Next, I swapped the stock headers for SSI, with a 2 in 1 out Bursch. The kick in the pants was very noticeable with the SSIs. The only problem is that I hated the sound of the Bursch 2 in 1 out. It sounded nothing like the Bursch 1 in 1 out I had previously and reminded me of someone spitting in a can. I then swapped the muffler for a M&K 2 in 2 out. All I can say is WOW! It's too loud for cruising around, but damn it sounds good. I have a plug that I put in one side when I'll be driving in neighborhoods or at night. It sounds JUST AS GOOD with the plug, just a lot quieter.

To make a short story long, you'll be VERY happy with SSIs and an M&K.

Plus, they look real purdy:



Don't forget, if you switch to SSIs, you have to switch 2 oil lines too. And the one that attaches to the thermostat is a pain in the a$$!

[mb911]

Originally Posted by SpeedracerIndy

When I got my car it had stock headers, cat and Bursch 1 in 1 out muffler. It sounded great, just a little louder than stock. The I swapped the cat for a euro pre-muffler with the bursch exhaust. That was a slight kick in the pants, but not huge and it was slightly louder. Next, I swapped the stock headers for SSI, with a 2 in 1 out Bursch. The kick in the pants was very noticeable with the SSIs. The only problem is that I hated the sound of the Bursch 2 in 1 out. It sounded nothing like the Bursch 1 in 1 out I had previously and reminded me of someone spitting in a can. I then swapped the muffler for a M&K 2 in 2 out. All I can say is WOW! It's too loud for cruising around, but damn it sounds good. I have a plug that I put in one side when I'll be driving in neighborhoods or at night. It sounds JUST AS GOOD with the plug, just a lot quieter.

To make a short story long, you'll be VERY happy with SSIs and an M&K.

Plus, they look real purdy:



Don't forget, if you switch to SSIs, you have to switch 2 oil lines too. And the one that attaches to the thermostat is a pain in the a$$!

Yeah the 2in 1 outs are 10 DBs less. I prefer them from a driver standpoint the 2outs are more for looks or for a big motor

[RWebb]

re: hardware

might try the search term "copper" + "NUT*"

there is a whole thread with vasrious idea on what is the best hardware to use -- I just used new stock stuff (see the PET for that) and either anti-sieze with Cu in it or Phillips Milk of Magnesia.

[stv951]

what about the cat on the car ?
Do SSIs bypass this or I need to buy a new one also ?

[stv951]

Are there two types of SSIs ? One with hesating and one without ?, or all these have heating ?
I wouldnt want to lose this

[snbush67]

Originally Posted by stv951

what about the cat on the car ?
Do SSIs bypass this or I need to buy a new one also ?

You lose the cat, there is no way to fit one in if you wanted to.

[snbush67]

Originally Posted by stv951

Are there two types of SSIs ? One with hesating and one without ?, or all these have heating ?
I wouldnt want to lose this

They have outlets for heat but you need to backdate your heater hoses. There is only one type. The only difference between the SSI's is the mounting flanges early were thin flange and later were thick.