Exhaust

Post by **crispy** » Tue Mar 02, 2004 9:46 pm

Hey guys,
It's nearly time for the exhaust to be made up and was just wondering what is the best size/ sizes to use and also what muffler to use?
Does the 2 stroke need more back pressure compared to a normal 4 stroke

thanks
Brad

Post by **stevec** » Wed Mar 03, 2004 10:21 am

You're opening up a can of worms there, Brad...

The exhaust system is what gives a two-stroke engine it's power. The first "muffler" is actually called an expansion chamber, and if this part is designed incorrectly, you'll have a top speed of about 5 mph. Behind the expansion chamber you must have a somewhat narrow outlet pipe, sometimes called a "stinger"; after that, it's just exhaust, and backpressure isn't much of an issue. I think 1.5" or 1.75" pipes, and a regular muffler is about it.

If you've got good fabrication skills for exhaust, including making cones of proper length and diameter, go for it; otherwise I'd suggest finding a shop that can make custom exhaust, and understands how a two-stroke engine works.

Post by **stevec** » Wed Mar 03, 2004 10:27 am

We're currently discussing expansion chambers under a different thread. Look under "LJ stories"...

Post by **crispy** » Wed Mar 03, 2004 6:02 pm

Yeah i thought it would be bit of a complex topic.
i know a good exhaust shop but im not too sure on what he like with 2 stroke suzuki's so i thought i'd get it from the guys that know first.

I realised that the first part of my exhaust from the manifold back to just past the expansion chamber is still in good condition- looks like it was replaced not so long ago.
But from there back looks to be the original with the little muffler right at the end and miniature pipe for it to exit.
So from the expansion chamber back do i just get the same as what was originally on there?
or can i go same size as what comes from the expansion chamber right through with an ordinary muffler in there?

Sorry about the long post and all the questions but if my exhaust guy has no idea i will hav to try to explain it to him, as there isnt many exhaust shops around where i live and dont know of many places that know much about LJ's here in oz for that matter

Thanks
Brad

Post by **Jimny** » Wed Mar 03, 2004 6:47 pm

No story is too long here, that is what we are here for. Ask how many no matter how long they are.

I'll let stevec reply. This is his department.

I'm going to move this to the Expansion Chambers thread so all LJ owners will view it if they have the same question.

I did it without deleting the wrong post this time!

Post by **crispy** » Thu Mar 04, 2004 1:06 am

yeah, cool no worries
thanks all :)

Post by **stevec** » Thu Mar 04, 2004 10:08 am

Yeah, the exhaust is basically in two sections: The expansion chamber section and the muffler section. The power is generated from the front section; the muffler and tailpipe can be replaced with just about anything that'll fit. I'd keep everything the same diameter as stock, though if you find a bigger muffler that fits in there, it shouldn't be a problem, and may quiet things down a little bit more.

Post by **crispy** » Fri Mar 05, 2004 5:06 pm

That's what i was hoping to hear

Thanks a lot for that

Post by **Jimny** » Fri Mar 05, 2004 6:14 pm

Let us know how it went Crispy.

Post by **crispy** » Sat Apr 17, 2004 1:05 am

Well i still haven't got a new back half of the exhaust made up, but i have bolted back on the original back half of the exhaust but i cut of the little muffler off.

It isn't really loud, may be even quieter than my sierra

After i get it rego'd then i'm coin to join on where i cut it off and put in a little resonator on then straight out