QUOTE(914_teener @ Oct 6 2023, 01:03 PM)
theoretically the 75 1.8 suffered no power loss over the 74 1.8 despite the "log" manifold design (for want of a better word) and the toilet S bend trap exhaust design that looks like a 19th century british sanitary engineer cooked it up.
Got to make it to NZ. Almost got there but landed in French Polynesia. I won't repeat the joke about the French flag there.....
Anyway...having had both SSI's and the stock 2.0 exhaust...I found the stock acutally gave ...at least by the "butt" feel...better low end torque. May plan was to exothermically paint them for heat savaging purposes...like they used to do for the Hot Rods to increase the flow characteristics. Maybe a project for later...but I found that the steel stock exhaust was better and that because the SSI's stress relieve at different rates....a property of SSI...had a tendency to crack and were absolutely hell to take off and reinstall if needed because of it.
My "Worldly" thoughts.
NZ is east of us in north antarctica.
its a dangerous place full of active volcanoes.
but you definitely should try and make it there.
i have a lot of kiwi friends - great people.
i haven't been there for 30 years but still remember going there fondly.
all jokes aside regarding the contortions of 75 log manifolds, which is sort of half true,
i honestly think the VW mufflers on 70-74 1.7 and 1.8 cars were no great shakes.
i always admire the beautiful curving heat exchanger pipe set up on my 1.8 but the beauty ends abruptly in the section of tree trunk VW called a bus muffler.
Those VW mufflers were a product of german TUV noise regulations more than anything else. poor old VWs (and also porsches) concentrated engine noise (in the VW case noise is perhaps flattery and clatter is a better term) and the exhaust outlet in one distinct peak as the test car went past the certifying microphone. this may have been slightly less of a problem in the 914 as the engine and exhaust outlet were just that little bit further apart to get two peaks on the microphone. the rear engined cars had the real problem and set the parameters for the muffler design.
or to say it in fewer words the VW muffler is all about noise reduction not exhaust flow.
the 75 and 76 cars were no longer bound by having to use an off the shelf VW part.
they got their own exhaust system with the cat etc.
its entirely possible that despite the contortions involved in all the 75/76 pipework that the mufflers themselves are actually better for exhaust flow than the old standard pre 75 mufflers.
i think somehow the 75 mufflers made up for the log manifold and u turn pipe and the playing field levelled enough for a 75 1.8 to pretty much not lose any of its precious few horses.
i am not sure but there might be a separate reason for the 75 2.0 L losing power over the earlier 2.0s. don't know enough about them. but perhaps still running D jet meant that they could not be made to meet emissions the same way the smaller cars could - L jet might have helped the smaller cars.
it is interesting that porsche chose to adapt L jet for the 2.0L 912e that used up the remaining stock of 2.0L engine short blocks. those 912e cars had to meet calendar year 76 emissions for california and USA. using L jet would seem to suggest that D jet could not be made to pass emissions without some serious compromising of power.
porsche and VW used a trick in USA emission laws to sneak the last of the D jet cars through in 76 MY. basically they had to stop making them by the end of 1975. they could qualify as 75 emissions cars that way.
