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My education continues.
I keep reading about SSI's. I need a bit of definition here. Is this short form for Stainless Steel Heat Exchanges? And how does that relate to the exhaust manifold?
Can someone just run though the exhaust system for me, and what the ideal "current" upgrade is? My VG E has Stainless Steel Heat Exchanges, but having never had an air-cooled car before, I'm not sure what that means, other than it is a very nice upgrade.
thanks in advance
larry
Larry, "SSI" is the brand name of the best stainless heat exchangers made. They are a stainless reproduction of the factory exchangers, so are a very good upgrade simply because they don't rust like the originals do. They don't add any power to our earlier cars, but are a power gain for later cars that came from the factory with a more restrictive exhaust.
PWD,
Thanks for the info, it is starting to make sense to me now. My car has Stainless heat exchanges, which is good. I don't know if they are made by SSI or not, but I guess that the mfg is less relevant to me as a purchaser of an existing car than the fact that the car has the stainless exchanges.
It sounds like the Heat Exchanges are part of the exhaust system. Are they part of the exhaust manifold? Where do they fit in the car? If we get really basic here and say that there is the engine block, then the exhaust manifold, then the exhaust pipe, then the muffler, where does the Heat Exchange fit in?
larry
SSI happens to be:Quote:
Originally posted by larry47us
PWD,
Thanks for the info, it is starting to make sense to me now. My car has Stainless heat exchanges, which is good. I don't know if they are made by SSI or not, but I guess that the mfg is less relevant to me as a purchaser of an existing car than the fact that the car has the stainless exchanges.
It sounds like the Heat Exchanges are part of the exhaust system. Are they part of the exhaust manifold? Where do they fit in the car? If we get really basic here and say that there is the engine block, then the exhaust manifold, then the exhaust pipe, then the muffler, where does the Heat Exchange fit in?
larry
Stainless Systems, Inc.
20 Pamaron Way
Novato, CA 94949
Work: 800.227.1486
Work: 415-883-2000
Other: http://www.StainlessSystemsInc.com
They are based on the 1967 911S exhaust, but (according to SSI's web site) they are true equal length headers, which means you get a little more power but one of the pipes blocks access to a mounting stud so getting them on or off is more difficult.
SSIs are both the heat exchanger and the exhaust header (the exhaust header pipes run inside the heat exchanger compartment). One end bolts to your cylinder heads (at the exhaust ports) and the other connects to the muffler.
I'm not certain how one would tell SSIs from another brand, except for a blocked exhaust stud access hole. SSIs are things of beauty, at least until you overfill your oil tank, but that's another story.
I've been told that stainless steel makes the car sound different.
Neunelf:
Thanks for the info. Now I understand completely.
Ian: Since I don't know how a stock early car sounds, I won't be the wiser (or dumber) when I actually hear mine fire up this spring.
It still amazes me that for 30 some odd years, I have lusted after a car, and even though I have never driven one, I now own one, and will take possession in April (if all goes well and the creek don't rise.)
Gonna be one hellova SPRING!!!! :D:D:D:D:D
larry
They are a much better header system than stock. If that makes the cars sound different then you have your answer. I can't really tell but my mechanic says it is different and can only be attributed to the headers.Quote:
Originally posted by Ian Morton
I've been told that stainless steel makes the car sound different.
Tom
AFAIK, each SSI has a stamped serial number on it, so it is easy to identify.Quote:
Originally posted by NeunElf
I'm not certain how one would tell SSIs from another brand, except for a blocked exhaust stud access hole.
http://members.rennlist.com/tweedt/ssinum.jpg
TT
Now that I understand the subject matter, I have been able to ask specific questions to my wrench about how my car is set up. I do have stainless heater boxes (exchanges) and that includes the exhaust manifold (or header) since this is all one unit.
But the unit that I have on my 73E is not made by SSI. He isn't sure of the manufacture, but says that it is different than the SSI in that it has a "pre-heater" for cold air that allows the car to run better when it is cold outside, because the intake air is warmed by the heat of the manifold. He said that it is similar to the cold air flapper box on the early cars, and thinks that it is more period correct than the SSI units.
You got me, I am just glad that it is stainless so that I don't have to worry about replacing a rusty one!!!
(BTW, Tom, what does AFAIK mean?)
larry
I have a set of SSI with a stainless steel dual in single out muffler. Since I am restoring my 1971 911S I don't think the concours judges are going to like these. Plus the SSIs have no provision for the cold start for the MFI. Bottom line is I would like to sell the whole setup for 850.00.
Thanks
David
David,
so a SSI exhaust doesnt quite work on a 70s with MFI?
I have always thought that whennit was time to replace my exhaust i would go with SSI but now i am not sure if it would work.
The last I checked the SSI Website, I thought I saw that they now offer headers for carbureted cars (no pre-heater) and headers for MFI cars (with pre-heater). As Far As I Know, SSI originally offered only the carburetor version.Quote:
Originally posted by larry47us
Now that I understand the subject matter, I have been able to ask specific questions to my wrench about how my car is set up. I do have stainless heater boxes (exchanges) and that includes the exhaust manifold (or header) since this is all one unit.
But the unit that I have on my 73E is not made by SSI. He isn't sure of the manufacture, but says that it is different than the SSI in that it has a "pre-heater" for cold air that allows the car to run better when it is cold outside, because the intake air is warmed by the heat of the manifold. He said that it is similar to the cold air flapper box on the early cars, and thinks that it is more period correct than the SSI units.
larry
You might still have SSIs--check http://www.StainlessSystemsInc.com
Oops. I just tried their website. Maybe their server is down, maybe SSI just went bankrupt. I don't know. I took a look at Performance Products website and they offer SSI headers for Carbureted cars and for MFI cars (the same on the right side--different left side headers for MFI and carbs). They cost $439.50 each.
My 1965 Porsche 911 has SSIs and a Jet Hot ceramic coated (silver colored) muffler. Concours judges don't seem to mind.Quote:
Originally posted by charlestonius
I have a set of SSI with a stainless steel dual in single out muffler. Since I am restoring my 1971 911S I don't think the concours judges are going to like these. Plus the SSIs have no provision for the cold start for the MFI. Bottom line is I would like to sell the whole setup for 850.00.
Thanks
David
Thanks, kinda get lost with some of this acronym-ineous stuff.Quote:
Originally posted by NeunElf
As Far As I Know, SSI originally offered only the carburetor version.
larry
SSI makes thin and thick mounting flanges for early cars, or later SC's and 3.2 Carrera.
Also, the thin flange for early cars are available with, or without the pre-heat for MFI.
You will find the SSI's work very well with the MFI. They do have the provision for the warm air hose to the thermostat. They just don't have the provision for the big warm air intake to the mechanism that runs to the air cleaner which everyone removes because is is a POS!Quote:
Originally posted by scargo70
David,
so a SSI exhaust doesnt quite work on a 70s with MFI?
I have always thought that whennit was time to replace my exhaust i would go with SSI but now i am not sure if it would work.
Kurt, I respectfully disagree. I'm still running factory exchangers, with that hose intact. Not everybody lives in SouCal...and up here, it's an aid when running/starting up in cold weather. If your intake is functioning properly, it's heat is cut off when running warm. So, not "everybody" has removed it...;)Quote:
Originally posted by Kurt V
You will find the SSI's work very well with the MFI. They do have the provision for the warm air hose to the thermostat. They just don't have the provision for the big warm air intake to the mechanism that runs to the air cleaner which everyone removes because is is a POS!
I think POS is a bit strong and predict that the parts that have been deep sixed over the years will one day be in great demand for "pure" restorations. Paul has one of the nicest cars and correct engine bays you will ever likely see.
It is my understanding (and I've heard many tales about this subject) is that there was a factory notice about these and something along the lines of a "removal of the unit" bulletin. Please don't hold me accountable for this tale because as far as I can tell it may be pure fiction and I don't surely don't want to anyone to believe what I say without the real facts on the subject. If someone like Roger Grago wants to chime in it would be appreciated. I do think something was in the air so to speak because you just don't see these anymore and cars like Paul’s beauty are an anomaly.
What I do know is what John Daniels at SSI told me in his own words. Apparently Chuck Stoddard directed him NOT to include that extra mini-heater box assembly when he was designing his heat exchangers way back when.
Chuck Stoddard was NOT a fan of the setup and had his reasons according to John. When the SSI's came out none of the left hand MFI exchangers have ever had any way to run warm up heat to the flapper/snorkel box attached to the air cleaner.
I have an OEM NOS original left hand exchanger and a very nice original right side one as well. They are stored with my flapper and other associated parts for it. I do not run it because I choose to use the SSI products, as they have always been a superior piece imho. They are capable of more hp, as they are a better header design than the originals.
The original MFI boxes are going to be gone one day and there won't be any more to be had unless Porsche follows BMW's lead and comes out with their own version of Mobile Tradition. Don't hold your breath because Porsche are not looking back anymore; they are just trying to survive (My bets are that VW is going to eat them one day; it's just a matter of time).
When the day comes to put the car at 100% I'll whip the originals out and in a half a day have it back just like it left the factory.
One other thing I've noted is that the '72-'73 rear tin that I have found has in at least 2 cases had what appeared to be a well thought out cap for the hole where the aluminum flex pipe for warm up heat would normally flow. I don't know if this was a factory part or something from the "shade tree" mechanic but they were definitely there and none were "jack-leg" rigs by any means.
FWIW,
Tom
PS: if you decide to throw yours away send them to me. I'm starting a collection.;)
Are they out of business? The link listed earlier in the thread appears to be dead.
But I think we should also clarify that the "pre-heater-flapper-box" unit that fed from the left exchanger to the air cleaner housing was only found on the 72-73 MFI cars (also on all of the later Euro 2.7 RS MFI engines up till 76 I believe). These cars also had the warm air supply from the left exchanger to the MFI pump thermostat.
The 69-71 MFI cars only had the warm air hose from the left exchanger to the MFI pump thermostat. No "pre-heater-flapper-box" to the air cleaner, as an example my 71S motor:
http://home.xshelton.com/~doug/images/motor.jpg
Can't seem to find any pictures of the 72-73 MFI "pre-heater-flapper-box" thingies since it sems most have removed them :rolleyes:
I guess I'm kinda slow.
I thought one of the "true" advantages of SSI's is that they allow post 74 Porsches get the performance advantage of the tuned exhuast that the early cars had as a stock feature. The fact SSI's are more corrosion resistant is just icing on the cake. For us early car owners, I would not expect much of a performance change between the stock and SSI exhaust systems since our headers are already "tuned".
Ok Tom,
Since I was called out, I will weigh in on this one. Please forgive me as I am going to have to rely on memory as I can't find the very old Porsche Service Bulletin. Around 77-78, Porsche issued a bulletin recommending removal of the air cleaner intake preheater on 72 and later MFI engines due to road debris ingestion issues. Also the intake preheating benefit was negligable except in extreme sub-zero conditions. The main reason for the intake preheater was for emission reduction on initial start up.
I removed the set up when I built my 2.7 RS engine almost twenty years ago. I installed SSI's and used the rear tin from a carburated engine (no hole). The set up has worked very well for me. Hope this helps.
All the best!
Roger Grago
PORSCHE Newport Beach
R Gruppe #27
Here's one for you.
Tom
Now, here's a man with a memory. I knew that it wasn't a rumor or that I dreamed it up. Thanks, Roger.Quote:
Originally posted by rst73
Ok Tom,
Since I was called out, I will weigh in on this one. All the best!
Roger Grago
PORSCHE Newport Beach
R Gruppe #27
Best,
Tom