Couple quick questions before i hit the sack.
1)Im haveing custom exaust pipe made up for my car and was wanting to know what would be the best Dia. pipe to go with? (1.8L 4-cyl)
2) What does a compresion ration mean, like 8.5:1...what do the numbers stand for?
Quick questions don't always ensure quick answers.
1. Since I'm somewhat familiar with your car I can tell you that 2" is plenty big. The stock size is 1 7/8", if you're keeping the cat there's no reason to go any bigger.
2. The shortest but not best way is to explain is to tell you that 8.5:1 compression means that the cylinder has 8.5 times the volume at BDC as it does at TDC. Use some of the sites that have been offered in various posts for further explantion.
Hey, you said quick.