TRX250R.ORG
Workshop => Carburetor, Intake, and Exhaust => Topic started by: hickwheeler on February 06, 2016, 03:15:28 PM
-
Well since my cm is not selling thinking about making it a standard mount. Question is should I use standard size stinger like ESR does or do I make it a true bb for my 330? So what are your guys thoughts.
-
What do ya need to do to make it non center? Is it a easy cut an reweld ?
-
I will get new stringer material. Then bend and weld in a new piece
-
Ok so the only difference is the stinger pipe that should be very simple.
-
At least I think so. Will not know for sure until I do it.
-
Wonder if it as simple as cutting the stinger pipe an just flipping it ? An some small modifications?
-
I think it needs more of a bend in it
-
Possible ya take it to a exhaust shop with a tube bender an get the bend ya need ?
-
I have a tubing bender
-
Your better of cutting it. It's difficult to bend pipe and not alter inner ID. Thats why mandrel bender are so popular/ expensive in any performance application, cause the inner ID does not change. Never seen a mandrel bender that small in diameter and I worked in exhaust shop for many years. There r other options to try for dirt guys.
-
I would use aluminum tubing, cause it's easier to manipulate with less pipe distortion/collapse. Try find something with a thick wall, that will let it stretch material an not get to thin. I would use a socket secured in a vice and heat, metric sockets will get u really snugg fit. I use to MAKE stuff work! Lol!!
-
I have a proper tubing bender. Not a pipe bender. Will be made out of steel so can be welded in place of piece I remove off pipe
-
Proper tubing bender makes the difference. You'll be good then. Most people don't know the difference.:buddythings0002:
-
Ya I have a pro tools 105hd with dies from 3/4" to 1 3/4"
-
Pm jerry hall he does this he recommended the bigger mod on my old trx11 pipe. I'm sure he could give some good advice.
-
I second Jerry Hall. He changed my stinger for my application.
-
If you have a b series you are more then fine. No big stinger mod is needed.
-
If you have a b series you are more then fine. No big stinger mod is needed.
This is only true if the power of your engine does not exceed a certain level and the period of time the engine runs at wide open throttle.
An engine used only for drag racing needs a lot of restriction to provide the engine with the correct back pressure for the short run at wide open throttle. The same engine used in a application where the engine runs at full throttle for more that 5 seconds will usually need less restriction where the exhaust exits the exhaust system. The heat continues to build in the exhaust system as the time at full throttle increases. Exhaust system internal static pressure increases as exhaust system temperature increases. It takes most two strokes exhaust systems at least 10 seconds to reach a temperature where the heat and static pressure reach it's max value.
Our motorcycle/ ATV industry is plagued with dynos that allow the power test to sweep through the usable RPM range on a 50 hp engine in less than 5 seconds. As the power level goes up, the length of time of a dyno run becomes shorter when run in inertial mode. Engine builders that use these dynos, are often innocently developing two-stroke exhaust systems that are more suited for drag racing only rather than pipes that are going to be run for longer periods of time.
Being slightly over restricted does not usually affect the power, it just causes the piston crown temperature to be higher than needed. If the stinger is severely over restricted to the point that there is a noticeable power loss, it will not usually raise the piston crown temperature.
The danger zone for pipe restriction is when you are near the limit of exhaust flow through the stinger and muffler that generates too much static pressure. The maximum allowable static pressure varies from engine to engine and depends upon how well your engine gets rid of the heat it generates. Cylinders with iron sleeves and light-weight pistons have trouble getting rid of the heat from key areas.
Keeping the stinger small is an easy way to produce good over-rev when there are mismatches in basic components that comprise your engine build.
The stinger inside diameter, stinger length and the flow characteristics of your muffler is what controls your pipe's internal static pressure. Static pressure is a function of the power the engine is developing.
The head pipe diameter is primarily a function of blow-down area of the exhaust port window. The internal shape of the exhaust port tunnel and to some degree the power the engine is making affects the needed head pipe internal diameter. Typically, as the displacement increases port size increases and the head pipe ID needs to be increased. Exhaust systems whose head pipes are too large will suffer from a loss in mid-range power. The loss in mid-range power depends upon the mismatch of head pipe diameter and engine build.