lt250dave

if the pics dont show up in the post, i will put them in my gallery on RC universe. I have tried numerous times to "resize" my photos with no luck, but i will try again.

the pix are of the handmade tuned pipe i am making for my baja

lt250dave

more pix of the pipe i am working on

aluminum crusher

your pipe looks like it's gonna be SWEET.[sm=thumbs_up.gif][sm=thumbs_up.gif]

lt250dave

the begining of the pipe is 3/4 inch conduit flared to a piece of 2 1/4 inch exhaust pipe that was tapered. the end piece is 1/2 inch conduit, not pictured yet but will be done tomorrow. this pic is what it should look like with my Jetpro silencer installed

lt250dave

thanks for the info,,,,


let me make this very CLEAR,,,this pipe is NOT for sale.

this post is for reference ONLY and i am NOT in business

aluminum crusher

COOL I'll take one of those please

aluminum crusher

BUT THE MODS WILL CHESTTIZE YOU ANYWAY FOR THEY ARE THE RULER'S AND CREATOR'S OF THIS UNIVERSE. HA HA HA LOL

lt250dave

o well i figured it was worth a try, even if they do delete this post i know several people will see it

aluminum crusher

RIGHT ON MY BROTHER...KEEP[sm=thumbs_up.gif] ON POSTING

Timmahh

all i can say is. .BLOWME. . A kiss as they leaveing baby, .BLOWME. .a kiss goodbye.
of all the things. i.m sure to miss, .wont you just. .BLOWME, .BLOWME .a Kissssssss.
lol
looking nice. hows it working?

Tinn

badz

My Feedback: (1)

They aren't just deleting posts. It's a group of trolls causing havoc here and 1 MOD happens to be their lacky and RCU needs to get rid of that MOD and the trolls.

lt250dave

i will try to keep you updated, i just finished some of the welding and i should be able to have it running this week, hopefully by wednesday

Earth Surfer

It's not what I would call a "tuned pipe", because I am sure that the length is too short for the RPM these engines make (its a sonic wave speed thing). But, the way you cut the pipe to form the reverse cone is very crafty. I have never seen anybody ever make a reverse cone the way you did. You have some fab skills man--I can tell. Neet idea.

Acs_guitars

My Feedback: (3)

I agree with him ^^^ The fact is that without the proper internal volume and correct section lengths you will more than likely hurt performance... Even worse than the stock can muffler and far from a "tuned pipe". assuming you have not (sorry if you have) Search the internet for 2-stroke tuning and you can find a lot of info about tuned pipe building, even formulas to help determine the "tuned" factors.

I can't say you don't do good work though... keep it up and with the right info you could end up with a winner that will hopefully look better than the JetPro on a Baja (it looks like a tumor hanging off the back to me).[&:]

BuggZy99

My Feedback: (2)

might be good on torque with that size but again, like others have stated, theres alot of calculations to be done to obtain good performance.... if it was so easy we would all make our own.

lt250dave

I didnt mean to get the ball rolling on two stroke tuning, i have had several two stroke quads and have made several different pipes for my nitro vehicles and i do understand that its not as simple as i might have made it sound by the title of the post.

The only real theory i was going on with the size of the "prototype" i am trying is a high rev top end pipe for a two stroke is often very long and with very little diameter of the expansion chamber like the two stroke boat pipes, and the indoor arena-cross quads that need all the torque they can get have a very short very large diameter expansion chamber to give max torque at low rpm's.

In all honesty i did no research on it because if it runs killer i can say i got it right on the first shot, however if it runs like a herd of turtles i can say well back to the drawing board.

I really like the performance of the Jetpro but every time i ran for more than two tanks of gas i would have to get a 12" 3/8 extension and the torch to straighten the darn thing back out. I also purchased a X-can but it was obnoxiously loud and fell on its face on the top end compared to the jetpro, thats why i figured i would give this one a try. here is the last pic of my jetpro bent so far that the roll cage was moved 3/4" out of location and a pic of the pipe before i put the flange on it

Earth Surfer

Every diameter, tapper and length of the sections of a pipe do a different job, and there is some pretty cheap software (and may be free) out there for designing pipes. The headersection and the defuser cone (the cone getting bigger) suck the exhaust gas out of the cylinder, and even help suck fresh fuel from the crank case through the transfer ports. Then the pipe goes into a straight belly section, and this section is used to time the sonic return wave to the cylinder just before to jam fresh fuel, that made it into the header section, back into the cylinder before the piston closes off the exhaust port on the up stroke. Then the convergent cone (the reverse cone) bounces back the positive wave back to the cylinder in realtion to the mean piston speed (which is related to RPM and stroke). The angles and lengths effect the timeing of the waves and suction, and the duration and magnitude of the forces. Agressive angles mean big forces, but low duration of the force, and visa versa. Porting, if done correctly is done to peak at a certain RPM that the user wants, and some pipe builders actually shorten the pipe so it peaks at a higher RPM than the porting in a effort to drag more RPM out of the engine--and it works quite often. If I may, I would like to give a prediction of what could happen if the pipe is too short. The return sonic wave reaches the cylinder too early, when the transfers are still open, and can force burnt exhaust gases down the transfer ports (what RPM this happens at has to be calculated). If you see burnt oil residue in your transfer port tunnels with your pipe, I would bet that is what is happening (that also happens with the stock can from what I have seen--but that is probably due to the can not bleeding down the pressure before the transfers open). I have had dirt bike engines with burnt residue on the transfer tunnels though, and they still ran very good at higher RPM's. Personally, I would not be suprised if your pipe runs better than a can, but I think your pipe, unsilenced will be even more loud than the x-can. End bleed pipes tend to be more noisy than side bleed pipes, and I have measured side bleed pipes with no silencer at 136 Dba when wide open. Your pipe may be 150 Dba (guessing)

But I still love the way you made the convergent cone. If I ever get my dyno finished (hopefully before I die), I may try my hand at pipe building, and that method of yours may be much easier to fabricate both cones, and a belly section from one straight piece. Production would probably be pretty labor intensive to make a lot of pipes that way, but for prototype testing, I really like the way you did that. Many pipe builders do what you did. They make pipes for testing that are straight, for ease of fabrication. Then after they get what they want, the bend the pipe to fit the chassie and try to keep the same tuned length. Thanks Dave man--like I said, that is a neet fab trick IMO.

hellya

I like the looks of your pipe too..... its tucked in and not sticking out like the jet pro or the samba

badz

My Feedback: (1)

lt250dave...if it doesn't perform well try tossing a cone inside like they have in alot of the nitro pipes, it increases backpressure and add's power....just a thought....i like the look ya got there hopefully it works out good you did a nice job on it.

lt250dave

thanks for the tips ESP, before i spend the time making another pipe (if this one doesnt work) i will surely look into pipe sizes and angles to try to maximize the space the baja has to work with.

I really didnt get to work on it today since i was busy with my real work [&o] but hopefully i can get the flange made tomorrow,,, ( i was just gonna cut the flange off the Jetpro but it was bad enough cutting the silencer off a $190 dollar pipe),,,, and take my buggy to work and get the pipe put on and make a hanger/ mounting tab so as to take the load off the head. i am gonna make a tab the goes to the down leg that runs from the top of left rear shock tower to the center of the chassis, right above the diff, so it will be easy to get to.

lt250dave

well i got the flange made today and welded it on. after all the time i put into this pipe i couldnt wait to fire it up. after blowing the pipe out for about 5 minutes to clear out any fab debris, i bolted it on and gave the rope a couple pulls and it came to life. I cant think of any good way to describe it, it doesnt sound like any pipe i have heard on a two stroke, its nothing like the Xcan and its nothing like the Jetpro without the silencer. it is truly different but dont get me wrong, it is LOUD. unfortunately night fall and the lack of 110 octane fuel got the best of me tonight so i will have to try it out tomorrow however it did free rev very well when i started it at work, it was very snappy and crisp sounding and went to top end with ease. I just hope it runs as good as it sounds

Acs_guitars

My Feedback: (3)

looking good.... Can't wait to hear how it goes!

aluminum crusher

Yeah can't wait to here how it goes can you post up a video with sound of the pipe.

lt250dave

My buddy and i are planning on taking out our Baja's this weekend if the weather holds out, he just bought a set of the CAW beadlocks and rock rings off ebay and mounted a set of the Maxx paddles. Those aluminum lock rings and rock rings really made the wheels stiff so it should help cure some of the rubbing issues and there is no way the wheels will invert now.

Now if he can just remember to charge the camera battery.

if we do get some video, i will need some help on posting it since i have never done that before.

lt250dave

i had figured on getting in some run time tonight to tune for the new pipe so i went to the local cycle shop and bought a gallon of VP racing C-12 and a bottle of Royal Purple two stroke oil, but wouldnt you know it has rained all day [:@], it is supposed to be nice tomorrow and part of saturday so maybe i can get some video. [sm=shades_smile.gif]


VP C-12

The best all around racing fuel made. Recommended for CRs below 15:1, satisfying the needs of 75% of today's race engines. One of the winningest fuels in racing history, including Modified Tour, GNN, D.I.R.T., Indy Lights, NHRA, AMA as well as other local and national championships across the U.S. and around the world.

• Color: Green
• Motor Octane: 108
• Specific gravity: .717 at 60° F

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