Tuned Pipe Questions

[Mr T-Maxx]

Say you install a "low end" pipe ie: Jammin' JP1

1. Does the top end suffer? Or will you notice no difference in the top end, but better punch on the low end?

2. Would the combination of a "low end" pipe and a higher tooth clutch bell negate the intentions of both changes?

I'm not grasping the concept of a "low end" pipe vs. a "high end" pipe.


Show me the light oh great minds of RCNT (you too Ratzo).

Thanks,

Mr T

 

[Plaidfish]

if you take a low end pipe on a engine that has low end torque then you want to gear it up 1 tooth on the CB....otherwise you get too much power and the wheels just spin.....the pipe tune is just the way the engine can "push" off of the pressure that's being created in the pipe....that's a rather vague discription but it works for me w/o having to draw a funky diagram.......some engines are just standard mills that have been experimented w/ to death on pipe / mill combos so people just go w/ that.....it's a good idea to have a few pipes handy to try on a new mill to see what kicks th emost arse.......

 

[Mr T-Maxx]

Good stuff Plaid, but I'm not sure you answered the question or maybe you did.

Installing a low end pipe does or does not affect the top end? If so, How?

Thanks Again.

Mr T

 

[Plaidfish]

it will affect it because it's tuned to give you more........pressure? (for lack of better word) for the engine to "push" from.....think of the exhaust pipe as a solid wall for your engine's combustion chamber to "push" from...yes the lil explosion that's happening is where it gets the real push from but if the exhaust port were totally open then all that push would just go out the port like a big puff....but when it get's caught by the pipe and some of that force is redirected back towards the port it gives the "wall" for the next combustion to push off of more....the tune (shape) on the pipe dictates where this "wall" is strongest........I have the calcs they use for this somewhere if you really want to be bored......LOL

 

[niggle]

Good stuff Plaid, but I'm not sure you answered the question or maybe you did.

Installing a low end pipe does or does not affect the top end? If so, How?

Thanks Again.

Mr T

Yes, it is highly likely that you will see a reduction in top-end power if you fit a low end pipe. This may be a good thing or a bad thing.

If you have an engine that is designed to give strong low-mid range performance and drive on a tight, technical track then fitting a low-end pipe and a clutch bell with more teeth is the way to go. Chances are that you will be pulling strongly out of the hairpins and will be half way down the straight before your buddys' screaming 8-ports have got on the pipe.

On a faster track you may lose out with this setup because the screaming engines have a higher top speed and will open up quite a lead on you on the long straights.

If you have an engine with more top-end than you can usefully put down on the track, then fitting a "mismatched" low-end pipe can tame this power, give you more tractability out of tight corners and reduce your fuel consumption into the bargain, maybe you will need one or two less fuel stops in those long A-mains.

Performance 2-stroke engines typically have a lot of overlap in the inlet and exhaust port timings, in theory the fresh inlet charge coming in through the inlet port can flow right across the cylinder and out of the exhaust port, the cylinder is never properly filled before the compression stroke and maximum power is never achieved. What the tuned pipe does is cause a reverse pressure wave at the exactly the right moment to push the escaping inlet charge back into the cylinder through the exhaust port. The engine is "supercharged" and the compression ratio and power are increased.

The length of the tuned pipe (and exhaust header) determines the engine speed at which the peak supercharging effect occurs. The width and taper profiles of the tuned pipe determine the intensity of the supercharging and the "power band" in which it occurrs.

 

[Mr T-Maxx]

Wow....Thanks Niggle....very informative!!

Mr T

 

[Plaidfish]

Sorry if I dumbed down my explanation of that....it's hard to guage when you go techno weenie on people.....

 

[niggle]

Sorry if I dumbed down my explanation of that....it's hard to guage when you go techno weenie on people.....

No problem, it's all good.

BTW, I'd be interested to see the calculations that you mentioned. I've set up a spreadsheet based on the tuned-pipe theory/maths but the constants that are used are really applicable to 1:1 gasoline (petrol) 2-strokes. Apparently the exhaust gas speeds are somewhat different in small methanol fuelled (glow) engines and you therefore need different constant values. Turns out the gas speed constants for gasoline 2-strokes were determined empirically (by trial and error) and no-one has worked out what the constants are for glow engines (yet).

 

[Plaidfish]

I did alot of reading on this a few months ago as I am trying to mod cheap engines.....I found a site on 2-stroke moto-X stuff that was real cool on it....they had tried the carbon fiber pipes and found they were absorbing the pressure in the pipe walls.....

I'll see if I still have the site saved t-morrow....going home and don't have Internet there anymore...too distracting....LOL

 

[c3racing0082]

I got a rs4-3(2spd) with a o.s .12 cv-r(x) Want to get either the rd-logic tuned 1 pipe or the turbo2 version. Any huge diff in the two? I heard the tuned onepipe is good for low and mid TQ and a t2 pipe is good for top end? Either way i go it will peplace my stock pipe with a broken stinger.

Just a basher though

 

[seajj2]

I have a jp-2 pipe on a LST and man what a difference. They are both good pipes. Also depends on the engine combination.