Last weekend I put the 83 JH code 1.8 I have spent the last 4 months rebuilding in my 79 Scirocco. Huge improvement over the 1.6, and it hasnt even been past 3500 rpm yet (100 miles on it). Everything inside the block is new. The timing belt cover was from the 1.6, the belt and the tensioner were replaced, and I took the best gears from both engines. The howl starts about 1000 rpm. You can adjust it out with the idle screw, but you always hear it somewhere near the perfect idle speed. The old 1.6 did it, and my brother in law's 83 Jetta (think it's a 1.7) does it also. The sound drives us both nuts. We thought it was the position of the tensioner, the 2 manuals we have show different views. I need to set the idle at 1200 rpm, because when you kick on the DPD A/C (dealer installed I think) the idle drops to 1000. I have the idle at 1000 now, not using the a/c. It just howls away. If I set the idle at 1200, no noise, but turn the a/c on and it howls away. The car is not smooth unless it idles around 1000 rpm, but the engine is still tight.
I am one of the few lucky ones that doesn't have to pass emissions, so I removed the EGR valve when I put the engine back in. Don't need a cat. The manifolds, double downpipe, and timing cover are from the 1.6. The exhaust system is stock, with the tiny hole at the bottom of the downpipe. All the exhaust systems I have seen on the net seem to deal with cats. I can probably have my brother in law fabricate a 2" or so flange on the downpipe and have a shop do the rest to the tailpipe, but i'd rather find something I can bolt in. I want to get the best mileage with the most power, as I usually drive it on the highway. Any ideas?