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Posted by: trick-e Jun 6 2021, 02:44 PM

Looking for a little help.
I’ve a ‘75 (originally a 1.8) upgraded with a ‘73 2.0.
I need a muffler, but am a bit confused on which one.
The heat exchanger exits into a single throat, triangle flange.
I ordered a used Bursch for a ‘73 2.0, but it’s a dual-throat ‘in’ and the trapezoid flange. Reading other threads/classifieds, the one I received should be the correct one.

So, different heat exchangers for different years of the 2.0?

I’m running a 4-tip Monza that’s rusted out.

-TK

Posted by: 914werke Jun 6 2021, 03:16 PM

Sounds like although you mtr was backdated they kept the late HE's.
2 choices: Backdate your HE's to the preferred early style & use the exhaust that you apparently just bought
Or : Buy an late exhaust (works on either 1.8 or 2.0L)
Only caviot to option 1 is that there are other bits & pieces that complete your heating system that are necessary (warm air guides, j-tubes, branch pipes)

PM sent

Posted by: euro911 Jun 6 2021, 03:41 PM

There were three different styles of heat exchangers (HEs) used on the 914s over the years.

1. Early HE's came on the '70 ~ '72.5 ('early') cars. They had two orifices on each side, with upswept ends on the tail end where the trapezoidal flanges are.

2. ('73 ~ '74 cars) with 2.0L had a different style of HEs that were similar, but had larger diameter pipes and less upsweep on the tail end where the trapezoidal muffler flanges are.

3. '75 &'76 1.8L & 2.0L (considered 'late' cars) had a set of HEs (the single orifice with a triangular muffler flange type).


It appears that you ordered a muffler that fits the '73 ~ '74 2.0L HEs - so you would need to source a set of 2.0L HEs for it ... or ... if you plan to keep the 'late' ('75/'76) HEs, you'll need to get a muffler that fits the 'late' HEs.


EDIT: I see Rich beat me to the answer(s) while I was slowly typing

Posted by: trick-e Jun 6 2021, 06:41 PM

Thank you all for the clarification. Now I know, and will be selling a muffler soon.

Cheers!

Posted by: VaccaRabite Jun 7 2021, 06:16 AM

You can get the later style muffler, but you should consider backdating your heat exchangers. The later style take some power away, which you free up with a set of SSI exchangers (which you can buy brand new).

Zach

Posted by: DRPHIL914 Jun 7 2021, 06:18 AM

just my opinion but unless you have a very original OEM concours car, i recommend getting the better more open HE, get the 2.0 to match your muffler. those 75 he were the worst most restrictive set up and cost you some significant HP>

either way enjoy, but get some new HE those old ones probably leak anyway- you can test to make sure , dont assume.

Posted by: davep Jun 7 2021, 06:55 AM

Pretty much a reiteration of the above, but there are three exhaust SYSTEMS over the years. A system comprises the heat exchangers, the muffler and the muffler hanger plus all the gaskets and seal rings. The 1.7 and 1.8 engines used one system from 1970 through 1974 model years. The 2.0 engines used one system from 1973 through 1974 model years. The final system was for 1975 & 1976 (all engines) and could include a catalytic converter next to the muffler. Each system basically requires the complete set of parts; no mixing of parts between systems.

Posted by: VaccaRabite Jun 7 2021, 07:00 AM

This is a good point. Since your exchangers are older and you have the muffler off, get a borescope off Amazon and inspect them. Rust/burn out can't be seen under the air jacket from the outside. But holes in the header tube will pump carbon monoxide into the cabin if you have heat hooked up.

Even better is to smoke test or pressure test, but if the exchangers are attached to the car a borescope will likely tell you what you need to know.

Zach

Posted by: 914werke Jun 7 2021, 10:04 AM

Here you go (late Bursch)

Posted by: trick-e Jun 7 2021, 11:18 AM

Gosh, thank you for the help.
Would like to get better HEs and get every drop of power out of that 2.0, but it’s not in the budget right now.

Thanks Rich for help finding the right muller.