Do SSI's "require" a dual-in muffler? or is single-in an option?

Just back from the second run - this time with dry roads. The more than ample butt says.....

Yes, I can feel an improvement in the acceleration from a stop and through the gears. It feels like the power comes on harder and is smoother through the rev range. The first time I jumped on it in first gear, it pulled past redline before I knew it (butt pucker), when previously power started to fizzle above 6K.

Again, I want to make it clear that this is very subjective. The change is not daylight and dark and others may not even get the same results. The best way I can describe it is like a really good tune up on an engine that needs one. The dyno should reveal the real story.

My total cost was with SSI's, Dansk muff, oil line, gaskets was about $1200. It took about 10 man hours to complete plus still have a couple hours clean up in garage. I can now honestly say that I'm really happy with the results.

Jam, you will need a 2 in muff.

Other than sound, do you think there would be a difference between the 1/1 and 1/2 Dansk sport mufflers on your car?

Ernie, not sure of the question. SSI's require a 2 in muff.

Thanks Mark. That's what I thought.

I'm currently getting an SSI/Dansk combo put on my 79 as well...except my Dansk is 2/2.
Thanks for posting about your experience. Sounds interesting and I'm definitely excited about your updates. Can't wait to give mine a try...although it'll be a while. :rolleyes:

jam

well...i cant say enough good things about my exhaust backdate on my 78. I have early HEs and a Triad Dual In/ Dual Out muffler. I noticed a huge difference right off the bat. still mild mannerd under 3500...but from about 4 to 6500 RPMs, its like night and day. It pulled so much harder than the stock setup...maybe my cat was clogged. I know that my original muffler sounded like it was filled with a hand full of bolts when i took it off and shook it; so that could have been part of the problem too. Anyway, things got even better after tinkering with the timing and the A/F mixture. Now if i could just shift a little cleaner with that pesky 915...

Mark,

Sorry for the confusion in my post. I was focused on the muffler. For my 89, I was considering replacement of the cat with either a Dansk or Fabspeed Euro Premuffler, followed by a sport exhaust. From the research I have done, I'm settled on either a Dansk or Fabspeed, but cannot decide on single vs dual outlets. Everyone will tell you that the duals produce a nicer sound; however, though I would like a good sound, the reason for going to a sport exhaust is performance, not for sound.

So, to rephrase my question: Assuming that I go with a single inlet muffler (Dansk or Fabspeed), would you pursue the single or dual outlet muffler?

Also noticed that you chose a Dansk muffler. Mind sharing your logic on that choice (which I believe was a good one).

Ernie,
First I'll say that I'm not an expert, but, here are some things I've gathered from reading the forum along with my experience.

- Typically, a dual out muffler will be louder and give a deeper tone.
- You may or may not get resonance problems with all aftermarket mufflers, but there seem to be more res complaints with dual out.
- Many people here have reported that the Fabspeed muffler is a Flowmaster in diguise. I had a Flow 1 in 2 out on my car for about a year and loved the sound - it is pretty loud, though.
- Dual outlets look a lot better than a single IMO.
- I honestly don't know if there is a performance increase with a dual out. You'll usually get as many opinions as people you ask, unfortunately. I've never seen dyno results one way or the other.

So, to answer your question, I guess I don't have an answer :( - sorry. My opinion, is that you choose your muffler by the amout of sound you want or can tolerate, and by the look you want.

I went with the Dansk stainless single out for a couple of reasons. I'm becoming an old fart and wanted a quieter exhaust and SSI recomends it as a match for their headers. Hope that helps.

Mark

I was thinking about your tranny rebuild the other day. How do you like it? I am nervous to spend the money and not have a big differnece. Can you shift into 3rd more quickly now?

How are you avoiding the smog Nazis in Redmond? Is your car old enough now?

My subjective impressions, without any data, on a 3.0 78SC, with Leistritz 2 in 1 out muffler, was that:

1. The powerband was broadened, before the SSIs, the push would come at around 3,000 RPM, now it seems to start much earlier. Also, the engine seems to rev more easily over 5,500 whereas it felt as though it was running out of breath beforehand.

2. Engine runs slightly cooler, also eliminated minor rattle from stock heat exchangers

3. Whole Exhaust weighs materially less than the stock system.

As everyone points out, this is one of the more affordable improvements to this model of 911, but as always, the bigger question is what comes next!

Mark,

Can you post a picture of your engine bay with the SSI's? How did you run your heat tubes? Imathinkin about gettin' a set, but I noticed they are all point outwards, unlike the stock exchangers pointing straight up. Did you change Tins?

EW, the tranny is doing great. No grind in any gears any more. It's still a 915, but shifting doesn't require "planning" any more. The car is 25, so no more smog in WA!!!!!

tsniu - great summary. Your results match mine.

Chad, the elbows on my stock HE's pointed outwards, in about the same position as the SSI's. Had to shorten the stock flex hose on one side to get it to connect to the header, but all the other tubes connected without problem. I still have the blower in the engine compartment (but not for long).

Mark,
You will not regret getting rid of the blower and backdating the heat. cleans up the engine compartment so nice and mine still provides enough heat to toast you.

Al

Mark, I've had my SSI/Dansk2/1 for almost two years now with no regrets. My G.F. really appreciates the instant heat response and those little red knobs seldom get lifted up all the way. BTW, I noticed on your gratis photograph that your 2/1 exits out on the right? How did you manage that?

Harlan, that's just a glamour shot from the file. It still has the 2 out in that pic. No new pics lately, the weather has been ummmmm....well, you live here.

My guess -- I could picture them providing a 12 to 20 HP improvement, mostly in the upper half of the rev range. I doubt that changing to SSI's will get you anything near 30 lb-ft of turque -- that would be a REALLY BIG improvement. I suspect that you might get a few more lb-ft across the rev range.

It will be interesting to see the before and after dyno graphs.

I don't know where the quoted figures are coming from on this post. Convention has it that SSi's will provide an extra 18-20 hp for 2.7 to 3 liter cars, but the diameters ae not optimized for the 3.2 and larger cars...so the gain expected should be 13 hp or so. Dual vs single "out" mufflers are 0-3 hp gain. Anxiously awaiting dyno confirmation here...but I'll bet I'm close.
As many have said, you can get nearly the same numbers by the combo of Euro premuffler in lieu of cat, plus chip and gutted or dual out muffler...nice thing about this combo is that you can re-insert cat quickly if ( ahem...) "needed"...like emission inspections. My car is going on the dyno in the Spring after hybernation....so far on a DynoJet 248C, my stock car with "generic" chip, drilled airbox, dual out/gutted mufler and cat....gave me 200 rear wheel hp ( 1985 3.2). Since then I've added premuffler and SteveW chip....I can't wait to see the numbers. I won't be surprised, however, if the top end numbers are not improved ( maybe lower?)....but mid range torque that you feel every moment of every day ( even coming out of turns on track days) is certainly improved.
----Wil Ferch

Kemo I've just received my 2/2 Triad exhaust and I have done the backdate to early heat excahangers too so I can't wait to try it (probably April as I'm re-furbishing the engine and the tranny). As well as the performance gain what does it sound like, a lot harder I imagine?
bones

I think SSI's are outstanding quality and a nice upgrade for the SC. For the 3.2 it's hard to justify- Wil said it all. Especially since the heater system needs to be reworked to get it plumbed back to normal.

Ernie,

If you're on the fence between the single or dual out, many have said the dual out Dansk is pretty loud with the SSIs. I'd go single out and i'm sure the growl is still there.

If you stay with the factory heat exchangers (I would) and go with a premuffler, check out Fabspeed's site and listen to the new video & sound clips they have of their mufflers. There's a noticeable difference in sound between their single and dual out 3.0/3.2 muffler that uses the factory heat exchangers and a premuffler. Single out sounds more like a 911. Dual out has more of a V8 type rumble to it. Kinda pricey though!

IMO, i'd get a painted, aluminzed sport Dansk. Saves you money (about half the price) and should last just about as long. Mufflers other than the Flowmaster/Dynomax/Magnaflow solution are just crazy expensive!!!!!

Harlan,

http://forums.pelicanparts.com/uploa...1075222922.jpg

Mine's on the other side too................ ;)

I agree about the 3.2/SSI issue, it is a complete waste of $$, IMO. Really expensive loudness, that's about it. :rolleyes:

As for Dansk mufflers, I am pretty sure that all of their "sport" muffs are polished aluminum, which model are you refering to? I have a painted Dansk 2 into 1 that is supposedly a stock '74 replacement, (~$200), it is w/o question the worst POS muffler that I have ever heard in my life. I am returning it under warrantee and getting something else, but under decel w/ my SSIs it sounds like a bunch of hobos in the backseat bending tin and pounding on empty coffee cans. I am not kidding. If this is the muff that you are talking about, for God's sake don't recommend it. :cool: