I know there are two different exhaust system for 1.7 and 2.0 (not mentionning the late 75 with cat that fits both 1.8 and 2.0) ...
Why did factory decide to change the old system (1969-1972 - 1.7) for the new one (1973-1974 - 2.0) ?
There are no obvious upgrade to the exhaust, same diameter, about the same length.
Trying to understand ... has this something to do with the sideshift change ?
Full Version: Trying to understand Exhaust system.
Are you referring to the difference between 70-74 vs. 75-76
Not totally clear on your question.
Not totally clear on your question.
As I see it;
1. 1.7-1.8l exhaust system - 4 tubes, back to muffler - up until 1974. (1.7 70-73, 1.8 74)
2. 2.0l exhaust system - 4 larger tubes with a different bend at the back - 73-74
3. 2.0-1.8l exhaust system - 2 to 1 branch pipes, single pipe back to catalytic (or pipe) multi piece muffler. 75-76
It is my understanding that the 2.0, dual tube, heat exchangers are larger in diameter and flow better.
Does that help? (feel free to reward me by sending a set of SSI 2.0l heat exchangers my way ,
)
1. 1.7-1.8l exhaust system - 4 tubes, back to muffler - up until 1974. (1.7 70-73, 1.8 74)
2. 2.0l exhaust system - 4 larger tubes with a different bend at the back - 73-74
3. 2.0-1.8l exhaust system - 2 to 1 branch pipes, single pipe back to catalytic (or pipe) multi piece muffler. 75-76
It is my understanding that the 2.0, dual tube, heat exchangers are larger in diameter and flow better.
Does that help? (feel free to reward me by sending a set of SSI 2.0l heat exchangers my way ,
)
Thanx for the pics
(Not talking about the 75 - 76 that are complettely different and fit both 1.8 and 2.0)
I have been told the (1973-1974) 2.0 exhaust has the same tube diameter as the 1.7 exhaust... Am I wrong ? ...
If they have the same diameter why did they change for the new exhaust for the (1973) 2.0 ?
(Not talking about the 75 - 76 that are complettely different and fit both 1.8 and 2.0)
I have been told the (1973-1974) 2.0 exhaust has the same tube diameter as the 1.7 exhaust... Am I wrong ? ...
If they have the same diameter why did they change for the new exhaust for the (1973) 2.0 ?
for 70 to 74 pipes
1.7/1.8 sytle has most narrow ID
2.0 has wider ID than above
2.0 SSI has wider ID than above - widest of all 3 styles.
most say the 75 to 76 style was for emissions purposes - not performance purposes?
jim
1.7/1.8 sytle has most narrow ID
2.0 has wider ID than above
2.0 SSI has wider ID than above - widest of all 3 styles.
most say the 75 to 76 style was for emissions purposes - not performance purposes?
jim
I knew I had seen a great write up on this subject. Here it is in great detail!!!!
http://www.914world.com/bbs2/index.php?sho...c=73563&hl=
http://www.914world.com/bbs2/index.php?sho...c=73563&hl=
I know this thread ...
Both 1.7 and 2.0 (not the 75-76) seem to have the same ID.
This doesn't answer the question, why did they made the shape of the exhaust different ? I mean it is shorter and has a different bent
Has this something to do with the sideshift gearbox ?
.
Both 1.7 and 2.0 (not the 75-76) seem to have the same ID.
This doesn't answer the question, why did they made the shape of the exhaust different ? I mean it is shorter and has a different bent
Has this something to do with the sideshift gearbox ?
.
this is the first time I've heard this on stock H/Es...
1.7 and 2.0 (pre-75) have different ID, UNLESS they are Stainless steel... then 1.7 and 2.0 have the same ID.
stock 1.7 < stock 2.0 < Stainless(1.7 or 2.0)
this is what I've heard for several years now... tho, all I've had is 1.7 stock and SS to compare... stock 1.7 was quite a bit smaller ID than the stainless 1.7
the thread linked above only looked at SSI H/Es... which is why they all had the same ID... no stock H/Es
1.7 and 2.0 (pre-75) have different ID, UNLESS they are Stainless steel... then 1.7 and 2.0 have the same ID.
stock 1.7 < stock 2.0 < Stainless(1.7 or 2.0)
this is what I've heard for several years now... tho, all I've had is 1.7 stock and SS to compare... stock 1.7 was quite a bit smaller ID than the stainless 1.7
the thread linked above only looked at SSI H/Es... which is why they all had the same ID... no stock H/Es
Sorry I thought that thread went into greater detail, but was just talking about SS HE's.
The standard 2.0 pipe 73-74 is larger and the muffler is larger. The 1.7 1.8 HE's go up at the end to meat the smaller muffler. The 2.0's can go straight to the larger muffler.
Maybe I am getting closer to answering your question. If not sorry!
Click to view attachment
The standard 2.0 pipe 73-74 is larger and the muffler is larger. The 1.7 1.8 HE's go up at the end to meat the smaller muffler. The 2.0's can go straight to the larger muffler.
Maybe I am getting closer to answering your question. If not sorry!
Click to view attachment
QUOTE(johannes @ Jun 8 2009, 12:28 PM) 
Am I wrong ? ...
Yes.
The stock 2.0L exhaust is larger in diameter than the 1.7L ...
However, the aftermarket stainless exhausts made by SSI have the same diameter tube for both the 1.7 and 2.0 ...
Andy
Things are becomming clearer ...
Could I wrench a full 1.7 exhaust on a late (1975) 1.8 engine or will I get troubles with the gearbox ? I ask that because 1.7 Exhausts are cheaper than 2.0, easier to find and would be an improvement to my late 75 restrictive exhaust.
Could I wrench a full 1.7 exhaust on a late (1975) 1.8 engine or will I get troubles with the gearbox ? I ask that because 1.7 Exhausts are cheaper than 2.0, easier to find and would be an improvement to my late 75 restrictive exhaust.
QUOTE(johannes @ Jun 8 2009, 01:16 PM)
Could I wrench a full 1.7 exhaust on a late (1975) 1.8 engine or will I get troubles with the gearbox ? I ask that because 1.7 Exhausts are cheaper than 2.0, easier to find and would be an improvement to my late 75 restrictive exhaust.
As long as you use all the pieces that come with the 1.7L exhaust, you can swap them over.
The best solution would be to get a set of SSI heat exchangers ...
Andy
any of the exhaust systems will match up to any /4 engine...
but all the parts from the engine back have to match...
H/Es, Muffler and muffler hanger...
with andy, get some SSI H/Es and go from there, make the rest of the pieces match what you get.
if you don't care about heat, the 75+ J tubes could be modified to become a poor man's header by pretty much any muffler shop.... all they would have to do is weld extended pipes on, and slap 1-2 small straight through mufflers.... ideally 4 to 1 pipe... but you could go with a glasspack on each side... straight pipes, chebbie style
but all the parts from the engine back have to match...
H/Es, Muffler and muffler hanger...
with andy, get some SSI H/Es and go from there, make the rest of the pieces match what you get.if you don't care about heat, the 75+ J tubes could be modified to become a poor man's header by pretty much any muffler shop.... all they would have to do is weld extended pipes on, and slap 1-2 small straight through mufflers.... ideally 4 to 1 pipe... but you could go with a glasspack on each side... straight pipes, chebbie style
You recommand SSI H/Es because of the larger ID ? are they lighter ? Do they last longer ?
Are SSI H/Es available new at a reasonable price? I have seen prices at AA (mad) ...
I care about heat ! ... I live in France and it's only warm a few month here.
Are SSI H/Es available new at a reasonable price? I have seen prices at AA (mad) ...
I care about heat ! ... I live in France and it's only warm a few month here.
QUOTE(johannes @ Jun 8 2009, 01:16 PM)
Could I wrench a full 1.7 exhaust on a late (1975) 1.8 engine or will I get troubles with the gearbox ? I ask that because 1.7 Exhausts are cheaper than 2.0, easier to find and would be an improvement to my late 75 restrictive exhaust.
I've got a 1.7 SS system with Bursch muffler on my 1974 engine/gearbox converted to 2.1 litre.
Here's a pic of the engine pending a quick tidy up which I did this winter.
The only major bit that is different between 1.7 and 2.0 is the bracket at the back of the gearbox. As you can see, mine has been butchered to fit, not done by me but I have to admint to not fixing it up!
Jon
QUOTE(johannes @ Jun 8 2009, 01:45 PM)
You recommand SSI H/Es because of the larger ID ? are they lighter ? Do they last longer ?
Are SSI H/Es available new at a reasonable price? I have seen prices at AA (mad) ...
I care about heat ! ... I live in France and it's only warm a few month here.
Larger ID and Stainless Steel. No more rust! and better heat as well ...
They've been out of production for over 10 years. So, good luck with finding a new set.
Used, they can be had for a reasonable price here in the US, shipping to France shouldn't be too bad.
QUOTE(SirAndy @ Jun 8 2009, 10:55 PM)
Used, they can be had for a reasonable price here in the US, shipping to France shouldn't be too bad.
Yea, I got mine on ebay in the US for $225 plus $125 for shipping. That was fine for me last year when the sterling to $ exchange rate was a bit better!!
Jon
Thank you for the
That is the kind of price I can afford ...
QUOTE
Yea, I got mine on ebay in the US for $225 plus $125 for shipping. That was fine for me last year when the sterling to $ exchange rate was a bit better!!
Jon
Jon
That is the kind of price I can afford ...
I had the 75-76 style HE's on my car when I got it then converted over. The car ran noticeably cooler and smoother. The SSI's almost put out too much heat. The difference in heat output is amazing.
If you find a set in the states let me know. I can help you out with the shipping if you can wait until I get back to Kaiserslautern 3 or 4 months from now (I don't pay any customs or taxes). I might be able to convince my wife to forward them on to you before I get back.
If you find a set in the states let me know. I can help you out with the shipping if you can wait until I get back to Kaiserslautern 3 or 4 months from now (I don't pay any customs or taxes). I might be able to convince my wife to forward them on to you before I get back.
Thank you for your help proposal. This could make it ! ...
http://cgi.ebay.com/ebaymotors/ws/eBayISAP...em=270403178145
...
http://cgi.ebay.com/ebaymotors/ws/eBayISAP...em=270403178145
...
you might even find a deal, too... I think I got mine for $125 + shipping when someone converted their street car to headers. keep your eyes peeled
those definitely seem like a good deal man, esp. with the shipping help offered above!
those definitely seem like a good deal man, esp. with the shipping help offered above!
QUOTE(tat2dphreak @ Jun 8 2009, 01:29 PM)
if you don't care about heat, the 75+ J tubes could be modified to become a poor man's header by pretty much any muffler shop.... all they would have to do is weld extended pipes on, and slap 1-2 small straight through mufflers.... ideally 4 to 1 pipe... but you could go with a glasspack on each side... straight pipes, chebbie style
cat. smogged 2.0 busses have these also. they are cast ase i recall
QUOTE(orange914 @ Jun 8 2009, 04:29 PM)
QUOTE(tat2dphreak @ Jun 8 2009, 01:29 PM)
if you don't care about heat, the 75+ J tubes could be modified to become a poor man's header by pretty much any muffler shop.... all they would have to do is weld extended pipes on, and slap 1-2 small straight through mufflers.... ideally 4 to 1 pipe... but you could go with a glasspack on each side... straight pipes, chebbie style
cat. smogged 2.0 busses have these also. they are cast ase i recall
They're NOT cast. The Cap'n
QUOTE(Cap'n Krusty @ Jun 8 2009, 04:19 PM)
QUOTE(orange914 @ Jun 8 2009, 04:29 PM)
QUOTE(tat2dphreak @ Jun 8 2009, 01:29 PM)
if you don't care about heat, the 75+ J tubes could be modified to become a poor man's header by pretty much any muffler shop.... all they would have to do is weld extended pipes on, and slap 1-2 small straight through mufflers.... ideally 4 to 1 pipe... but you could go with a glasspack on each side... straight pipes, chebbie style
cat. smogged 2.0 busses have these also. they are cast ase i recall
They're NOT cast. The Cap'n
o.k., time & age thing
. i do remembr sealing issues and had to surface the flanges, still had issues with the sealing surfaces that were unevenly thin
The SS HE's that are for both the 1.7 and 2.0 have the same internal volume.
I suspect the change was so that Porsche could use the Porsche 2.0 liter muffler (looks alot like a 911 muffler of the same era) versus using the VW bus muffler which is what was on the 1.7 and 1.8 motors.
Rich
I suspect the change was so that Porsche could use the Porsche 2.0 liter muffler (looks alot like a 911 muffler of the same era) versus using the VW bus muffler which is what was on the 1.7 and 1.8 motors.
Rich
The VW bus muffler was maybe too restrictive or too loud when adapted on the 2.0 engine
.
.
There were a lot of emissions changes going on at that time and the changes might be emissions related. The larger muffler volume allows more expansion space for the exhaust gas and might reduce backpressure slightly to reduce an exhaust gas emission.
The larger pipes and muffler also provide a slight increase in power. Remember, the power of the 1.7 engine was falling due to emissions controls, and the the 2.0 was an attempt to get power back up to the early car levels.
Or, maybe they changed the muffler due to noise restriction changes.
It could be they met three goals with the change- more power, reduced emission, and a sound change.
The larger pipes and muffler also provide a slight increase in power. Remember, the power of the 1.7 engine was falling due to emissions controls, and the the 2.0 was an attempt to get power back up to the early car levels.
Or, maybe they changed the muffler due to noise restriction changes.
It could be they met three goals with the change- more power, reduced emission, and a sound change.
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