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How to: SQUISHBAND your engine

charge

Veteran
hi haen, your method does help. thanks a lot!

Anyway, I can't feel much difference after shaving 0.6mm off. Just a bit more torque in overall. Still like the rush of my racing cam at high rpm.
 
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goff_d_p35

Guest
What is the overall performance of having 1mm shaved off the bottom of the block? a higher CR would mean what??

when the 1mm is shaved, is it best to use stock gasket, or the three bond. and if you still want to keep the use of the gasket, should you go 1.1mm?? I'm thinking of getting it done, but i am not sure what the full benefit is.

I would really like to understand.
 

haen

Super Veteran
@charge : glad to hear it works for u.. next.. go for big valve head bro (promo mode : ON :) ) or use the TK Racing Valve..
 

charge

Veteran
hahaha, I really want the TK valve. Haen, how can you read my mind knowing that will be my next upgrade??!!

Justkir, just wondering, your ABM cam is low cam or high-cam?
 
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goff_d_p35

Guest
Please, Someone answer my full question??


What is the overall performance of having 1mm shaved off the bottom of the block? a higher CR would mean what??

when the 1mm is shaved, is it best to use stock gasket, or the three bond. and if you still want to keep the use of the gasket, should you go 1.1mm?? I'm thinking of getting it done, but i am not sure what the full benefit is.

I would really like to understand.
 

haen

Super Veteran
hey goff 1 mm = 0.5 mm block shave + 0.5 mm from lower block gasket removal, overall performance please ask traxx for tat.. higher CR means more power, at the expense of heat, vibration, sometimes engine and parts durability.. but if all correctly mixed it won't pose much a problem..
 

traxxas-modifier

Super LOLO
Staff member
goff_d_p35 said:
What is the overall performance of having 1mm shaved off the bottom of the block? a higher CR would mean what??

when the 1mm is shaved, is it best to use stock gasket, or the three bond. and if you still want to keep the use of the gasket, should you go 1.1mm?? I'm thinking of getting it done, but i am not sure what the full benefit is.

I would really like to understand.
bro shaving off will increase compression ratio.
increased compression ratio means ENGINE IS MORE EFFICIENT.
MORE POWER/TORQUE at the same amount of fuel used.

its like a firecracker,
considering same amount of gunpowder used:

-if a firecracker were packed TIGHTLY very tight..
it will give a BIG BANG

-while a firecracker were packed loosely, it will just give
a "puff" bang hehehe

that same principle on highly compressed engine.
as what haen said, highcompression tends to make our engine runs more hotter... but since our engine is LIQUID COOLED... no problem..
again this mod is for tough guys only who wants to get try major mods... :)
besides, if something goes wrong, parts are easy to obtain :)

so a highcompression engine will give more torque/power.
changing it to more highspeed sprocket will give more topspeed.

but for me, i love the jolt it produces, a small throttle twist, you feel the responsiveness of your engine
especially on traffic :)

VROOM VROOM! hehehe
 

charge

Veteran
I have cold start issue, need to close the choke for 1 minute for the bike to warm up. I guess the pilot jet is too small for my modified carb intake. Now the pilot air screw is only turned to 1 1/5 compared to Yamaha's recommended 1 5/8, else I will have start up problem.

I do feel the low rpm response increased. Going steep uphill with 4th gear is possible now. However, the top speed is around the same too, it doesn't help me too much at the high rpm.
 
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goff_d_p35

Guest
Thanks Traxx. I'm thinking of having it done. i know i will need to change the exhaust, cdi, pilot jet, and valve springs. but i want the ( O.M.G. feeling that your going to fall off the back of the bike.)
 

traxxas-modifier

Super LOLO
Staff member
charge said:
I have cold start issue, need to close the choke for 1 minute for the bike to warm up. I guess the pilot jet is too small for my modified carb intake. Now the pilot air screw is only turned to 1 1/5 compared to Yamaha's recommended 1 5/8, else I will have start up problem.

I do feel the low rpm response increased. Going steep uphill with 4th gear is possible now. However, the top speed is around the same too, it doesn't help me too much at the high rpm.
bro i dont have cold startup issue :)
in fact my choke is removed already
(from carb tip) so no choke installed.
one click or two clicks start in morning :)


maybe you need to increase your pilot to #22.5
yes 4th gear gives a better power now. hehe

@goff
if you want the feeling of fall off the back.
go for vixion! this mod wont fall you off
and dont expect too much.

this mod just gives better than stock setting..

i suggest when you do this mod, be prepared for anything that will happen...
at your own risk as they say , hehehe

again, any mods that will make add power than stock setting
is good :)
 

charge

Veteran
traxxas-modifier said:
bro i dont have cold startup issue :)
in fact my choke is removed already
(from carb tip) so no choke installed.
one click or two clicks start in morning :)

maybe you need to increase your pilot to #22.5
yes 4th gear gives a better power now. hehe
That's great bro Traxx!!
May I know what is your needle position? Mine is at the topest 'tick', if going down to center or lower 'tick', the throttle response will be sluggish :(
Hmph... another question is, I heard from a friend that pilot jet allows more air into carb. Should it be more air, or more fuel? I am confused @_@
 

traxxas-modifier

Super LOLO
Staff member
hi bro

i use pilotjet #22.5
neddle jet is on middle clip.

pilot jet controls fuel from idle to 1/4throttle
so it allows fuel and not air.

if you want more air intake go for highflow airfilter
like k&n or other highflow filters you want.
 

charge

Veteran
Yo traxx, I ady have the airbox removed and the air intake portion of the carb is polished. It currently looks like a small funnel :p

and thanks for clearing my doubt bro!
 
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goff_d_p35

Guest
Hey traxx, Question?? If i remove the two gaskets Top of block and bottom of block, will I achieve an increase in compression?
 

Azzurri

New Member
1st thing you have to know is, gasket is a mechanical seal that fills the space between two objects, generally to prevent leakage between the two objects while under compression.
2nd if you remove it, can it increase compression while your block already leaking? huhu
 

Azzurri

New Member
@haen right! Man u're always be the pro hehe :D

@charge
The "Porting and Polishing" Myth

It is popularly held that enlarging the ports to the maximum possible size and applying a mirror finish is what porting is. However that is not so. Some ports may be enlarged to their maximum possible size (in keeping with the highest level of aerodynamic efficiency) but those engines are highly developed very high speed units where the actual size of the ports has become a restriction. Often the size of the port is reduced to increase power. A mirror finish of the port does not provide the increase that intuition would suggest. In fact, within intake systems, the surface is usually deliberately textured to a degree of uniform roughness to encourage fuel deposited on the port walls to evaporate quickly. A rough surface on selected areas of the port may also alter flow by energizing the boundary layer, which can alter the flow path noticeably, possibly increasing flow. Flow bench testing shows that the difference between a mirror finished intake port and a rough textured port is typically less than 1%.

The reason that polished ports are not advantageous from a flow standpoint is that at the interface between the metal wall and the air, the air speed is ZERO (see boundary layer and laminar flow). This is due to the wetting action of the air and indeed all fluids. The first layer of molecules adheres to the wall and does not move significantly. The rest of the flow field must shear past which develops a velocity profile (or gradient) across the duct. In order for surface roughness to impact flow appreciably, the high spots must be high enough to protrude into the faster moving air toward the center. Only a very rough surface does this. :D
 

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