Pipe design is complicated by the many variables. The art of pipe design is to combine the lengths, angles and diameters of the pipe to suit the characteristics of the engine, especially the exhaust timing and end use.
Some examples are;
Small volume - high heat - narrow operating range (peaky)
High volume - lower power (if too big) - broad range
Steep angles - 'peaky' - high power
Shallow angles - broad range - moderate power
Smaller or larger diameter stinger - lower or higher pressures and heat.
There are a multitude of ways of quoting pipe length. The most accurate method (and most rarely used) is to quote the distance from the piston face to the Mean Reflection Point (MRP). The MRP is the average point of the reflected wave forces. Many people quote a length of plug to the high point, which is easy when pipes have a clearly defined high point ... most modern pipes have a flat or mildly curved center section which is used to "tune" the operational power band..smoother, wider etc.etc.

AFM

Why don't we read agian articles on the web sites I posted on the beginning of this thread.
Generaly-longer pipe kick in earlier and give us benefit at lower RPM, but it will not bring us to highest possible RPM. Short pipe will ki9kck in later at higher RPM range will give us much higher topr RPM level, but engine first has to reach that leve when pipe will start making charging ( resonance effect).
At any lenght of pipe, it will not start working till engine reach RPM on which pipe is tuned. If engine isn't able to reach that level, pipe will never bring any benefits ( resonace charging).
:nod:
Start from longest possible pipe and run it, after that start shortening it, till you will find the best effect-don't forget at differnt load engine will go to level differently-more load takes more time to get there.;) :D

That is correct. This arguement is my fault. Typed my first post back to front and didnt realise.

Sorry everyone.

Totally agree with that TG, that is why there are so many pipes out there in the market, and each manufacturer and it's different models of pipe try to enhance different "power bands", but if you don't tune them correctly to your engine and application, they are worthless.
But lets not confuse the pipe's lenght by itself with total exhaust lenght, that is why i think that the best explained method is the one given by RB Products and it is called "pipe to manifold lenght", which will give us the effects you so well explained.

Sorry if i got confused between those two concepts that started this argument (pipe lenght vs total exhaust lenght), that in the end has been very productive for everyone.

AFM

Quote:" BTW, I saw new Mugen pipe on Robby Collins car-that is blasting pipe".
Top Gun

Where can i get info on that pipe TG, is it similar to the new Novarossi 52606 Efra/52607Turbo, which in turn are similar to Novamega's TPO6 2170 Efra/2172 Outlaw????

AFM

I asked Robby last Sunday, it is not ready for public, so I don't think they will revile any info on it. It looks similar to all Novas pipes, but it is not made by Novarossi, somebody else did it. They got other modify version, but didn't work that well. Sorry, can't help you with that.
I send them email, but didn't get respond yet.

Thanks a lot TG, guess will have to wait. But don't forget to post here as soon as you get info back.....you see i'm the "pipe man" jajajajajaja...because I believe it's most important engine tuning accesory.

AFM

;) :D
I will post anything I got from them. May be this Saturday will have more info.;) :nod:

Was it this pipe?

Seems exactly like this!!!!!!!!! Is it on sale already?

I don't know, but it's on their website

http://www.mugenracing.com/whatsnew/msrcomppipe.htm

Unfortunately it is not available for public yet.:cry:

No way man i saw my lhs selling them yesterday.:)

Thanks for info. Will check tomorow too, I want to that pipe badly!!!!!!!!!!!!!!:nod:

looks like a NovaMega pipe. must be different on the inside. Too bad it's a 2 piece, I'd hate to loose my coupler in the middle of a race.

Stefan,I sent you a PM. :blush:

Well guys, been doing some research and I think we have our new generation of pipes for the recent crop of Nova based engines. The thing goes like this:

Novamega:
2170 In-line set M12 Efra TPO6
2172 In-line set M12 Outlaw TPO6

Novarossi:
52606 In-line set Efra .12
52607 In line set Turbo .12

Mugen Seiki Racing:
S01001 MSR Standard .12 pipe
S01002 MSR Outlaw .12 pipe

And I bet they all perform the same in each model.

AFM

TG, you got PM

Thanks,

Steven Muller
MPP Team palmaris Racing

Re: Re: Re: Re: fuel consumption and hp
 

what ? you got caught again huh? told you not to use fake id with a woman's picture on it, you never listen.

that is probably true. i did notice the difference in run time when i remove the restrictor on the carb. on the same engine.

same carb. ?

Re: Re: Re: Re: Re: fuel consumption and hp
 

so what is the one main change you can do to the engine to make it more efficient. i know there are probably many things you can do, but what change, or combination of change that will contribute the most to the gain in hp but at the same time won't increase fuel consumption too much.


i did modify the needle once but accroding to my friend who tried it, he didn't really notice any changes in engine performance so i put it aside. i probably didn't do it right or i should had tested it myself. by the way, what do you think the "mid. range" screw really does ? to me it adjust the spray bar position, relative to the low end needle, but i don't really know what it does to the engine. the only thing i can think of is this adjustment controls how soon the low end needle leaves the spray bar completely. if i were on the right track, what would be the advantage/disadvantage of having the low end needle leaving the spary bar completely sooner/later ?

me.

p.s. saw you modify the exhaust timing the other day, i guess one can learn something new everyday. thank you

Re: Re: Re: Re: Re: Re: fuel consumption and hp
 

Setting your clutch correctly can have just as big an effect on fuel consumption as it does on acceleration.
Moving the spraybar within the carb venturi affects when the low speed needle completely unseats from the bar. As such, you can move the powerband slightly by moving the spray bar if you also move the lowend needle in the same direction.

Re: Re: Re: Re: Re: Re: fuel consumption and hp
 

Data my friend;

http://www.rcnitro.com/rn/articles/carburetor.asp

This is a good short article on the subject with some nice cut away pics which are really helpful ! ;)

Now I'm getting confused.:confused: :confused::weird: After reading the article it seems that I have been tunning my engine all wrong. They say that the low-speed needle is the one that is on the slide valve. Is that so and if it is what have I been doing for over an year and a half. I use the brass needle to tune the low-speed mixture and it works well. Can someone please explain me one more time which needle is about what, pls. I really am confused.

Data - I was using the same carb. You know how it is. When you get a good carb you keep it.

Speed De - The low speed needle is the one on the slide bar. The brass one on the opposite side is the spraybar adjustment. It is not actually a needle (the low end needle enters it) but instead alters the postion of the powerband on the engine. A lot of people use the spraybar to adjust the low end without realising that they are altering how the engine performs.

Data, in our engines is everything in siquence and there is no one particular thing which can be modded to increase power. We just have to make sure ( when we do modding) everything is right and on time.
About the carb modding-it will not add a lot of top end power ( we are talking about carbs which initialy done well-Novas, Sirios etc), but we can inrease respond, we can encrease efficiencyduring the accelaration, decrease unneccesary fuel loss on not wide open moments etc.
About the timing altering you saw-it is unique today, I hope you got point what I did there. I am sure very soon someone will copy it and I am OK with that.:D
Will be at CP this Saturday, we can talk more.:nod:

CRANKSHAFTS
 

TG
What are the advantages and disadvantages of full circular crank's counterbalance vs delta or semidelta shaped ones (RB).
At one point, and i think still, the MT12's and REX MR12 have full circular, and Novamegas up to the 2103 also.
Can you explain please???
AFM

Rotating mass!

Isn't only a matter of rotating mass... is a matter too of aerodinamics and the way the mix of air and fuel travels behind the crankshaft (that's why lately many crankshafts are cut with a very agressive ramps.

Carbs 101.
 

The 'brass screw' isn't a needle. Is the main jet of the carburetor. After this lines, there's a complete text describing how our carburetors work. Seems that many people gets puzzled with all the needles and how to adjust them. I suppose a minimum knowledge on where's the high-end needle, low-end needle, spraybar or main jet and idle speed screw.

The screw in front to the 'brass screw' (located at the side of the carburetor and usually flush to the surface of the carb body) is really the low-end needle. And it plugs into the main jet without obstruding completely to allow a little of fuel to pass when the needle plugs into it to allow the engine to idle.

The dimensions of the jet, their position relative to the venturi, and the dimensions, ramps and shape of the low-end needle dictates the fuel curve of the carburetor (or how much fuel enters by each cfm of air drawn into the engine at a relative carb opening).

At idle speed, the engine is controlled by the low-end needle and how much air pass into the engine via the position of the barrel. But when you start to move the barrel to allow to pass more air, in fact, you're moving too the low-end needle, allowing at the same time to pass more fuel too.

Depending at which opening of the barrel, the jet is totally uncovered and the carburetor starts to being mandated by the adjustment of the high-end needle and how much fuel permits to pass this last adjustment rathern than being governed by the low-end needle. This can be varied (and the powerband of the engine too, but slightly) by screwing or unscrewing the jet and readjusting the low-end needle. But be careful screwing the jet too further into the ventury can lead to mix and temperature problems (in fact, you're leaning the mid rpms, where the engine operates at partial opening of the carb, this can lead to problems and erratic operation) this is why on almost all the engine booklets warns you about to not touching this adjustment.

The position of the jet, relative to the venturi changes too the position on where in the vortex of air when enters into the carb and varies too how much or how finely is the fuel sprayed into the air that enters (fuel is converted into a mist for being burned, a drop, no matter how little is doesn't burn and can create many and serious problems). This last can lead up to a conrod breakage (common) or piston breakage (not common but seen some) due to hydrolock.

In my opinion not too much differnce, beside mixing ( which not realy proven yet). As long as it is balanced more or less close, the shape realy doesn't metter, that shape , which you see on the pic ( world champion in speed air modeling), of delta is done to create counter weight. Some people will talk about cranckcase volume, but it has been proven years ago, any cuts on web ( conter weight) don't make crancase volume bigger at all.
I preferd delta-it is asking less thikness of counterweight on opposite side of cranck pin area, which is realy realated to crancase volume.

Thanks, will experiment on the track with both types of crank on the same engine (exchanging), and post my "real world" results later.
afm

ok, maybe you can explain this sequence/timing thing to me sometime.

but i think it is kind of dangerous, one wrong cut and that is it. i will leave this mod to the experts.

good, then i can pick your brains at point blank.

I will, may be this weekend at CP

It is dengerouse, one very small wrong movement and everything will go to trash. Leave it to modifyers, they know what they doing, you just have fun driving.

See you Saturday.;) :nod:

Hey guys I want to know what everyone is using to cut there ports (like increasing exhaust timing) so there will not be any burrs left on the inside of the sleeve. I am using a fine grinding bit in my dremel. Anybody using something that leaves smoother cuts? Or is there a good technique for removing burrs?

I am using fine cut diamond needle files only ( longer, but for sure straight). After cutting I am using hone ( bought in Automotive store) for cleaning burrs. I always do it with hone-it is not realy scratching chrome, but remove all hangings easy.

hone
 

Edward I bet you using a wheel cylinder hone arent you! :D

:nod: All I know about modding engines is to leave it to the experts. I just love the results, thanks Edward! :nod:

Definately a lot of Palmaris Racing guys on this forum. Things keep going as they are and myself and TopGun will have to start organising Palmaris Racing cup events:lol:

Guess you have to go where the power is:nod: