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> Trying to understand Exhaust system., Why did factory change for 2.0 ?
johannes
post Jun 8 2009, 01:54 PM
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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 ?
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thompson-mfr
post Jun 8 2009, 02:11 PM
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Are you referring to the difference between 70-74 vs. 75-76

Not totally clear on your question.
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Cupomeat
post Jun 8 2009, 02:12 PM
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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 , (IMG:style_emoticons/default/happy11.gif) )
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thompson-mfr
post Jun 8 2009, 02:25 PM
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I love pictures! These pictures from Jimkelly thread.

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thompson-mfr
post Jun 8 2009, 02:26 PM
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Pictures of some I sold a while back 75-76 Heat Exchangers

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johannes
post Jun 8 2009, 02:28 PM
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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 ?
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jimkelly
post Jun 8 2009, 02:33 PM
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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
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thompson-mfr
post Jun 8 2009, 02:34 PM
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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=
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johannes
post Jun 8 2009, 02:37 PM
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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 ?

.
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tat2dphreak
post Jun 8 2009, 03:04 PM
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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
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thompson-mfr
post Jun 8 2009, 03:06 PM
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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!

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SirAndy
post Jun 8 2009, 03:15 PM
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QUOTE(johannes @ Jun 8 2009, 12:28 PM) *
Am I wrong ? ...

Yes. (IMG:style_emoticons/default/biggrin.gif)

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 ...

(IMG:style_emoticons/default/shades.gif) Andy
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johannes
post Jun 8 2009, 03:16 PM
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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.
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SirAndy
post Jun 8 2009, 03:20 PM
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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 ...
(IMG:style_emoticons/default/bye1.gif) Andy
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tat2dphreak
post Jun 8 2009, 03:29 PM
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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...

(IMG:style_emoticons/default/agree.gif) 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
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johannes
post Jun 8 2009, 03:45 PM
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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.
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jonat127
post Jun 8 2009, 03:50 PM
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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.
(IMG:http://i271.photobucket.com/albums/jj133/jonat127/P1110477a-1.jpg)

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!
(IMG:http://i271.photobucket.com/albums/jj133/jonat127/P1110473.jpg)

Jon
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SirAndy
post Jun 8 2009, 03:55 PM
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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.
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jonat127
post Jun 8 2009, 04:03 PM
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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
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johannes
post Jun 8 2009, 04:09 PM
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Thank you for the
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


That is the kind of price I can afford ...
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