Custom Pipe Design

[Rubbersalt]

Looks like I'll be build a new pipe for my friends blaster soon. I've done plenty of math/research/made a pipe before on my yt175 with good results. The thread for that is on here at 3wheelerworld.com
So, I decided I'd share with the world, some of the information. Everything is going to be based off of my brother, N8tsNastyBlasty's Port design.

So before i post up pics, I'll mention something I noticed with all blasters. It's a stretch to reach 35hp without big bore/stroking. Most dyno's i see are 30-35hp. My program has estimated power ratings relative to displacement/rpm/compression. It's a long stretch to reach 52HP with a 200cc engine runnin 10,500rpm. The biggest factor is heat, at 52hp with 10500 on a 200cc engine, your looking at exhaust temps close to 712c. This probably doesn't mean much until you realize the blaster shouldn't push over 500c. When the exhaust temps are high, so are the piston, cylinder, rod, and everything else . To much heat and you'll seize your piston(you can get them thermally coated). I have a feeling that the cooling fins on my brothers and my friends blasters will have the cooling fins extended... So, with all that being said, I'm going to toss up a couple of ideas.

First is first, A drag racing pipe set up that is good for drag racing and then COOLING DOWN, it will be so much heat, you can only run short runs.

!!!All designs are for ported engines!!!

Peak power produced at 10,500RPM, 36mm Carb recommended, 50HP peak, narrow power band. 160PSI comp - I dunno about the gasoline part - pushing the limits at 160psi.

The next pipe is more of what I would consider a trail pipe. It's got a very very wide power band that peaks at 8500rpm. It's setup with no triple port exhaust, but a port timing of 185exhaust and 125 transfers. Port/pipe are set to the target RPM range. 30mm Carb recommended. Low heat, 475C. 135psi comp

This next pipe is for Nate, Set up for his port job(triple ports, ect), his peak RPM, and a nice Wide power band. Heat is on the brink of 500C. 145psi comp

 

[N8tsNastyBlasty]

my comp was around 160-165 last time we check wasnt it? but to reach the 50hp we r gonna need methanol. Mine sounds like it hit around 10000 rpm! i need a tach but evryone at the dunes said it sounded more like a shee than a blaster when it was rapped out. I just thought it sounded awesome! lets get the pipe built soon!!! after i build my bug motor im doing more port work on the blasty's

 

[Rubbersalt]

Funny story about that thing sounding like a shee.. Me and Preston heard you coming, looked over and it was a shee lol.

The porting program says your close to 50hp at 10500. Of course, thats with the perfect pipe/port work/ignition timing/everything else I'm sure. 145psi gave 38hp to match.

 

[Paulie B]

Interesting. I'm tuned in for this one I:I

 

[blasterfreek30]

Interesting. I'm tuned in for this one I:I

same here man, i was thinking of something like this today

 

[N8tsNastyBlasty]

hopefully we'll all be "tuned" in when it's all said and done.lol (pun)

 

[Rubbersalt]

I got my computer set up here(near the blasters) with all the software and programs and information I'll need. Just need a few measurements and ideas before i get to work on it.

Looking at the frame, we may modify it to fit the pipe, Less bends in the pipe the better, and i see a way to soften the bend in the fattest part. That is the most crucial of the part of the pipe.

For the most part, pipes size are determined by 3 things.
First - BMEP - how much power are you going to make, more power=more heat=shorter engine life
Second - RPM range - Where do you want your power to hit, how wide of a powerband
Third - exhaust port size - The bigger the port, the wider the pipe.

The first 2 determine the length. Higher rpm=shorter pipe, higher heat=longer pipe.

Sound waves hit the reflector cone and bounce back, the goal is to get it back at the piston when the port is still open. At certain rpm ranges, the port is closed, or doesn't close fast enough.

Heat makes the sound waves travel faster. The more heat your pipe makes, the longer it needs to be so the sound waves arrive at the same time.

Thick metal pipes retain heat making the power more consistent, but they are heavy.

Stingers width is crucial. Wide stingers allow more sound to go out of the pipe, they also make pipes run colder. Narrow stingers do the opposite.

Now - stingers can be internal. This quiets the pipe significantly and helps retain the sound waves while exhausting the same amount as a stinger stuck on the end of the pipe.

Just some random info for you guys.

 

[blaster7]

man I'll take one laughs,no really sounds great bud,I'll be watching for the results and then I'll make one,at least try any ways.

 

[yzrider]

wow, u guys are rlly knowledgeable, haha

 

[scotj77]

tuned in. hopfully it won't be a looney tune. lol

 

[brandoz28]

awesome stuff guys!!! can't wait to see how this comes out

 

[N8tsNastyBlasty]

After we end up with a pipe i find most suitable for my builds i may make dies and try stamping out a few, but this is in the distant future. Also im considering fooling with adjustable pipes like some or the aftermarket 250r stuff.

 

[1995blaster]

or the adjustable lrd like i have. but i have noticed almost no change in power when adjusted maybe throttle response. but if so didnt register on the ass dyno

 

[Awk08]

very good stuff !!!!!
but are you guys sure you can hit 10,500 rpm with a stock, unbalanced crank ????
i'd have to see tach numbers.

 

[Paulie B]

If you guys are tuning for 10k rpms look out. Im sure it will make alot of hp but have zero torque and a bible paper thin powerband. Please reasure me

 

[Rubbersalt]

The main issue isn't the cranks, but the rings and connecting rod. ASt 10500, the powerband would be somewhat wide for nate's design. But 10500 is pushing it hard.

Ring flutter becomes a major concern at about 10k rpm. Longer rod or thinner piston rings help the issue. I forget why thinner rings help, but the longer rod helps the angle of rod - >piston during the strokes. This puts less stress on the side of the piston and rings.

For spywell build, I'll probably due a 9500RPM design, he should be shifting before 10k rpm.

The 2 biggest factors for limiting power on these engines is the cooling and the ring. So.. these pipes produce alot of power, more than you see from the other guys. We plan on extending the coolign fins. I've even thought about going as far as making a 5mm spacer and sticking a banshee rod in there. Also turnign the jug into a water cooled jug but i have no water pump yet :\

 

[Paulie B]

The thinner ring provides less friction and drag then the regular one.

 

[Paulie B]

The thinner ring provides less friction and drag then the regular one.

*Edit* at home now and off the droid so it's easier to type.
The thinner ring is a fairly common mod for small (23-31cc) Zenoah based weed wacker motors. These motors I'm pretty familiar with lol
The way these motors were designed in the beginning was for durability but ever since the large scale RC market got a hold of them they have been re-designed for higher rpm and more power.
They went from a 2 ring design, to one 1mm ring to the modern day .7mm ring.

 

[Racer51]

To bad you cant make a blaster water cooled that'd probably fix it?you might have to do what o'connor did with his crank it terms of HP over torque. What bore are you planning on doing? The real problem your faced with is if you want this thing to have the life spand of a gnat, or to be as healthy as a horse waiting for another 300ft beating and still be able to rip off the head of the other guy trying to keep up with you.

 

[Paulie B]

Run alcohol cooling problem solved.