One or Two exhaust pipes Jab 3300

[Thruster87]

Any advantages or disadvantages [noise,power output etc] with having one hoon size exhaust outlet [from the muffler] or the two smaller pipes.Getting close to putting the muffler on the Jab 3300 engine.Cheers T87

 

 

[Guest brentc]

The single outlet from Jabiru is a newer design and you'll also notice the 3 outlets go into the muffler as a group on each side, whereas on the older engines the pipes joined up earlier closer to the engine and went in as a single pipe, but out as two. The single exhaust model does supposedly assist the engine in producing more power, mainly because the curves are designed to be a smoother radius.

 

 

[xair1159]

Does the same apply to the 2200 engine? Late 07 / early08 some turned up here with single pipes and then later deliveries were back to the twin pipes.

 

 

[jetboy]

My 2200 was supplied with the 2 outlet pipes but not fitted. I chose to have a 2" single pipe centered at the midpoint of the muffler and exiting at a slant out the bottom. I got the welder guy to copy the hole pattern on the portion inside the muffler like the stock pipes. The original pipes had different number and pattern of holes each whether thats intentional or just production tolerances who knows.

 

The B22 Bantams seem to be fitted with just 1 stock tailpipe.

 

I dont know how noisy I am compared to stock, some observers have said it sounds and flies like a Hughes300 others say a big iron Cessna (but not as fast)

 

It runs a whisker over 3300 on climbout some days so the flows are OK

 

Ralph / CH701

 

 

[Thruster87]

Brentc, Any idea on the Diameter of the single exhaust pipe? and are they putting the outlet approx. center of the muffler or to the sides Cheers T87

 

 

[gofastclint]

Are you looking at just fitting a new muffler or a whole exhaust?

 

Your motor has even firing pulses per bank so 3 equal length pipes merging into one on both side will give you great scavengeing effect, and as both pulses from these 2 pipes is exactly opposite they can then merge into 1 for a secondary scavenge effect.

 

P plate drivers often fit large cannon style mufflers in an attempt to gain more hp only to be upset at dyno time when they see a large drop in bottom and mid range power (the same type of rpm we use in takeoff for the same size engine). A good and cheap muffler to fit would be a stock super bike muffler, as its quiet, very light and can handle the gas flow.

 

 

[Harthy]

Exhaust outlets

 

Guys,

 

At the risk of saying what you probably all know. A lot of care needs to be taken before altering exhaust systems on any engine.

 

The exhaust system can make or break the performance of any engine, more so on a two stroke engine.

 

As it has been mentioned, scavenging is what it is all about (Process where exiting exhaust gases create a low presure area that draw more exhaust gases from the cylinder and also add in filling the cylinder with a freash charge of air and fuel) . Getting the same amount of scavenging for each cylinder to obtain even output is important. Even output means a smoother running engine, which leads onto other benifits like more over all power and revs.

 

Manufactures spend heaps of money on research to obatain a good balance of economy and power and the exhaust system is one area that is done.

 

You have probably all heard of extractors before, When I was younger the talk was to put extractors on your car and it will go like a rocket. Well it will if matched correctly to your engine. If not, no difference could be noticed or even a decline in performance.

 

Each exhaust pipe leaving each cylinder need to be allowing the same amount of flow, and restrictions like bends also influence this. So correct length of each pipe is important.

 

The other problem is, different systems are set up to perform better at certain revs then others.

 

So we all need to be careful here.

 

One other thing I am sure you all know. 1/4 bigger in diameter outlet pipe size has doubled the flow area or output which ever way you would like to call it.

 

If over all performance doesn't worry you, then just plumb it up so you get them gases out of there.

 

I use to teach engine operation, and a quote I use to tell the young guys was, 'If you want to get power out of engine you need to get air and fuel into the engine and exhaust gases out, how well you do that determines the outcome'.

 

Hope you don't mind my 2 bobs worth,

 

Harthy

 

 

[facthunter]

4 & 6 cyls.

 

Flat 6 Cyl. engines have even pulses in each bank of 3 (Side). Flat 4's are more difficult , requiring pairing of each row. ie. opposite cyls fire evenly.

 

This requires a design of a "Cross-over" type which has more heat dispersal/insulation problems, and difficult to get equal length The exhaust system should be suspended from the engine and move with it, unless flexible connections or spherical faced joints are used . All in all, a hard thing to get right . Nev..

 

 

[Thruster87]

I'm fitting a NEW engine into a NEW Zenith 601xl.I was just wondering into the pros and cons of the single or dual exhaust outlets from the muffler, which are tig welded in place.Cheers