[gandgracing]

Have seen some other R's that have the TRX 11 inframe pipe and they have shortend the silencer. Whats the benefit? Thought about this do to ESR building a 3" silencer instead of the 2.75".

 

[2R's]

short silencer's ( in general ) make for more bottom end ..

 

[BLACKeR]

yep.

 

[gandgracing]

I called ESR about their new silencers and they aren't for the inframe. They also said that a shorter stinger will make more top-end.

 

[blasterman88]

shortining the silencer makes for more top end. it also helps reduce EGT temp

 

[gandgracing]

thats the R I saw with the shorty. Guess i'll leave mine alone if it makes more topend.

 

[BLACKeR]

im curious about it making more topend. FMF's shorty silencer is advertised as making more bottom end. and in application is used typically for tight tracks, and XC. pro circuit also makes a shorty silencer for low to mid RPM's.

 

[gandgracing]

It seems to me that it would be more for top end, but I have seen some threads that all say its for bottom end. If I could find a straight answer that it helps bottom end then I would give it a try.

 

[86 Quad R]

It seems to me that it would be more for top end, but I have seen some threads that all say its for bottom end. If I could find a straight answer that it helps bottom end then I would give it a try.

buy an old silencer like the one that your currently running, shorten it, and do a "seat of the pants" comparrison. that quad i built for my son has one on it but, i honestly couldnt tell a bit of difference in it as apposed to mine. ofcourse, we're talking about two different engine setups.

 

[2R's]

my answer/post is based my information & studies on the smaller motors my daugter races ..
experienced builders have stated this .. & I have seen horsepower & rpm charts ...

1 example is the FMF system offered & we have for her KTM 65 the "powercore silencer" is shorter than stock & is well known for making more bottom end power ,even when is used with a stock head pipe

 

[BLACKeR]

there are definitely discrepancies. both pro circuit and FMF advertise their shorter silencer as more responsive in the low end or making more low end power. however i found this tidbit from eric gorr.

"Silencers come in all sorts of shapes and sizes. A long silencer with a small diameter enhance the low to mid power because it increases the bleed-down pressure in the pipe. A silencer with a short length and a large core diameter provides the best bleed-down pressure for a high rpm engine. Too much pressure in the pipe at high rpm will radically increase the temperature of the piston crown and could cause the piston to seize in the cylinder."

http://www.geocities.com/rssarma/articles/eric.htm

maybe Neil can weigh in on this.

 

[Michael88R]

I would say that comparing a big bore drag pipe & silencer to FMF and Pro Circuit is not apples to apples. The whole purpose of the centermount pipes is to get the heat out quicker on those big bores. So shorten it down and its even quicker.

 

[fourtrax250r]

a shorter silencer lowers egt. hotter gases flow faster which helps top end. especially for drag racing you want a hot expansion chamber and a longer silencer will heat it up more.

 

[fourtrax250r]

and center mount has a shorter stinger not a shorter silencer

 

[blasterman88]

Fourtrax is 100% correct..... you also have to remember stinger length of the actual pipe as well, and essentialy you are changing the stinger length with the silencer. the FMF and pro circuit MX pipes could be set up compltetly different!