silencer questions

[CR480R]

Does the the length of pipe between the pipe and silencer have an affect on power? Also I was curious if silencer length and core diameter have much affect? I ask this because I was wanting to adapt a longer(quieter) silencer onto my LT. I also have a fmf powecore that I wanted to adapt onto my tecate, and wondered if It would hurt to shorten the stinger a bit? FTZ sells silencers with an oversize core. Would this be similar to running a 500 silencer?

[yamaharider02]

i belive i read sumwhere that the lenght of the silnecer makes a diffrence.. the longer the more low end power, and the shorter the more top end power.

[HardIzzle]

yea yamaharider right but i think it goes by inchs

[CR480R]

anybody know of a good place to find info on this subject ?

[nd4speed]

Tuning for Specific Powerbands


Component: Cylinder Head

Low To Midrange: 9.5:1 compression ratio, squish band 60% of bore area

Midrange and High-Rpm: 8:1 compression ratio, 40% squish

Component: Cylinder Ports

Low To Midrange: Exhaust port 90 ATDC, transfer ports 118 ATDC

Midrange and High-Rpm: Exhaust port 84 ATDC, transfer ports 116 ATDC

Component: Reeds

Low To Midrange: Dual-stage or .4mm fiberglass petals.

Compromise: Thick carbon fiber petals

Midrange and High-Rpm: Large area 30-degree valve

Component: Carburetor

Low To Midrange: Smaller diameter or sleeved down carb (26mm for 80cc, 34mm for 125cc, 36mm 250cc)

Midrange and High-Rpm: Larger carb (28mm for 80cc, 38mm for 125cc, 39.5mm 250cc)

Component: Pipe

Low To Midrange: Fatty or Torque

Midrange and High-Rpm: Desert or Rpm

Component: Silencer or Spark arrestor

Low To Midrange: Short, small diameter

Midrange and High-Rpm: Long, large diameter

Component: Ignition Timing Advance timing

Low To Midrange: Stock timing

Midrange and High-Rpm: Retard timing

Component: Flywheel

Low To Midrange: Add weight

Compromise: Stock flywheel

Midrange and High-Rpm: PVL internal flywheel

Component: Fuel

Low To Midrange: Super unleaded 93 octane

Midrange and High-Rpm: Racing fuel 105 octane

[ONLY2STROKES]

not all of this info is correct..for low-mid you run a 93 m.o. fuel???for mid-high r's you retard the timing???

[CR480R]

is that from eric gorr's site?

[zillaguy89]

yeah....some of that I agree with and some I don't. Like every tom dick and harry can't just go pick up a PVL or Motoplat ignition for thier quad, nor can everyone afford it. So they lighten the stock flywheel instead...Plus....running 105 octane fuel in a stock engnie is just pissin money away...and the porting numbers.....I'm no porting whiz, but 84 degrees ATDC on a honda 125 is not gonna be the same as 84deg. ATDC on a yamaha 250.

Your initial question.....the lengts of stinger tubes and silencers do make a difference, but probably not enough of one to make a big enough difference to write home about...

just my 2 shillings

[CR480R]

Yeah I do alot of "sneakin" around on my LT, and was considering a larger silencer off of something else like a fmf turbine core or fmf Q. I just dont want a serious decrease in power.

[zillaguy89]

i hear that....i know the FMF pipe I had on my zilla was louder than all hell with the Powercore silencer....