Exhausts for dummies

[Benno]

So my escort failed its wof on holes in the exhaust system. I had previously put a bandage on there, and got through again with some exhaust putty but have decided that I should get it sorted properly. There is rust in both the pipe and rear muffler, so it's probably not worth just patching up. I'd like to learn a bit about it and make an informed decision instead of just taking it to an exhaust place and getting whats cheapest. I did a search and couldn't find much explaining exhaust systems in detail. I already have a set of Coby extractors fitted. I don't want something loud and droning, but wouldn't mind a bit of an exhaust note as long as it was a reasonable volume and didn't drone too much while at cruising speeds.

I will be keeping the 1300 engine in it for the forseeable future, but would like to potentially upgrade to a 1600 in the future. It currently has the factory (1.5"?) system fitted. After looking through some build threads, it seems that 2" is the way to go. There was a noticeable difference in both economy and performance after I fitted the extractors, am I likely to notice anything similar with a new full system?

What is my best bet for a muffler? It currently has a main muffler, then either a small secondary muffler or resonator. Is sticking with two the best bet, or would a single larger one be better? Is the muffler better to go closer to the engine or rear of car? Any types or brands better/cheaper then others?

Is a flexi-joint necessary? If so, i guess it would go straight after the extractors to counter any engine movement?

Any ball park figures as to how much I should expect this to set me back?

Cheers

[camo_78]

i have 2 1/4" on the mk5 sport with a single muffler.its not loud but as NZford can tell you,it has a nice note.im far from an expert on exhausts though,i took it to Mark at pitstop hornby(ive known him via friends for a few years),and basically said"i want something more performance orientated but not obnoxiously loud, and NO fart cannons",cost me 425 inc GST all up

[kpr]

reso up front and a half decent muffler at the back is the usual, and works. pipe size from a performance point of view; usually a short distance after the extractors end, will be "tuned length." from there pipe size doesn't really matter. long as it flows more than whats in front of it.

guessing the oulet/ collector on extractors will be 2" or smaller ? if you wanted to get fancy you could try:

extractors -> 250-300mm of collector pipe -> step up to 2 1/4" pipe to reso muffler location -> reso -> more 2 1/4 pipe to rear muffler location -> rear muffler, with a bit of length after it will make it quieter.

rear muffler will be the biggest restriction. so use a 2.5" muffler if its anything other than straight through, which you wont want.

ah and you can chuck a flexi in there if you care,

[Styles]

Here're my thoughts, and I'm no pro on exhaust stuff.

I'd agree with 2" being fine, probably oversized for a 1300, but still more than adequate for a 1600. Or go with the diameter of the collector/end pipe of the extractors.

How much difference in performance and economy would be minimal. Don't be too surprised if your economy drops because you're giving it more welly cos it sounds better!

For mufflers I'm a fan of straight through mufflers, which probably are a little louder, so you need more/bigger mufflers, but they tend to have a nice smooth tone rather than being harsh. I have Borla mufflers, but they're expensive. You can probably get away with a hot dog/bullett/glass pack/"resonator" up front and as large a muffler at the back you can fit. If you go with straight through I'd recommend using as big a muffler up front (and rear) as you can.

For rear drive/longitudinal cars a flexi joint isn't strictly necessary, I wouldn't stress about it too much, as long as the system is well supported.

Do a bunch of googling and take what you read with a pinch of salt.

I guess the best people to ask/refer to are fellow esky owners (which I am not), mr camo_78 up there seems pretty happy with his, and he's presumably near you, perhaps check his stuff out!

[tehnzbrad]

got a quote from pitstop for $420 for a full 2.25" exhaust with one coby.... if that helps and yeah a flexy joint will help because the bottom curve of the cobys crack... and get really weak and give lots of leaks.