R/C Tech Forums

Go Back   R/C Tech Forums > General Forums > Nitro On-Road > Onroad Nitro Engine Zone

Reply
 
Thread Tools Search this Thread
Old 01-06-2004, 04:45 PM   #31
Tech Initiate
 
Join Date: Jul 2002
Location: Singapore
Posts: 45
Default Re: Re: Re: Re: Re: Re: Re: fuel consumption and hp

Quote:
Originally posted by Top Gun 777
We have to move spray bar closer to center of hole, reshape bottom end needle ( most important step-right shape-made three needles before got right shape), and it will be moved in till right tunning for idle.
Right now I am preparing drawings to make conversion kit for common carbs. Hope will be done very soon
Thanks TG.What do you think if there is a tunable tune pipe.Someone from this forum ever mention about making this type of pipe.Lets say I shorten or lengthen it by about 10mm to 20 mm.What difference does it make?
IronMan is offline   Reply With Quote
Old 01-06-2004, 06:43 PM   #32
Tech Master
 
modellor's Avatar
 
Join Date: Aug 2002
Location: Northern Ireland
Posts: 1,447
Default

Increasing the length of the pipe will help produce more power at the top end while shortening the length will produce more torque.

But with the .12 engines the differences are barely noticeable unless the engine is really tuned to perfection.
modellor is offline   Reply With Quote
Old 01-06-2004, 09:28 PM   #33
Tech Elite
 
stefan's Avatar
 
Join Date: Aug 2001
Location: Bavaria, Germany
Posts: 3,273
Send a message via AIM to stefan
Default

Sorry, but my experience is that the longer pipe gives you more torque while the shorter on gives more rpm's.
stefan is offline   Reply With Quote
Old 01-06-2004, 09:40 PM   #34
Tech Fanatic
 
EVOLUTION's Avatar
 
Join Date: May 2003
Location: Everywhere,yet Nowhere!
Posts: 978
Default

Quote:
Originally posted by modellor
Increasing the length of the pipe will help produce more power at the top end while shortening the length will produce more torque.
I too thought it was the other way around.
EVOLUTION is offline   Reply With Quote
Old 01-06-2004, 09:43 PM   #35
afm
Tech Master
 
afm's Avatar
 
Join Date: Nov 2003
Location: lima-peru
Posts: 1,807
Default

Quote:
Originally posted by stefan
Sorry, but my experience is that the longer pipe gives you more torque while the shorter on gives more rpm's.
Sorry, but I agree with Modellor, lets not confuse header to pipe lenght, which gives you what you are saying. Actual pipe size goes the way Modellor says. My experience with Picco and Sirio engines, which are a mid-lenght conrod engines and so have a bit more torque, have their pipes very long (difficult to fit in most cars) because they try to enhance top-end. I remember that the Picco pipe was the hot ticket for the Mugen MT12 engine (long conrod).

AFM
afm is offline   Reply With Quote
Old 01-06-2004, 09:51 PM   #36
Tech Champion
 
Manticore's Avatar
R/C Tech Charter Subscriber
 
Join Date: Aug 2001
Location: Heaven
Posts: 9,999
Default

http://www.rbproducts.com/rbww/faqrb...erformance.htm

read it carefully and check out what does "pipe length" mean there.
Manticore is offline   Reply With Quote
Old 01-06-2004, 10:05 PM   #37
afm
Tech Master
 
afm's Avatar
 
Join Date: Nov 2003
Location: lima-peru
Posts: 1,807
Default

Quote:
Originally posted by Manticore
http://www.rbproducts.com/rbww/faqrb...erformance.htm

read it carefully and check out what does "pipe length" mean there.
Manticore, that's what I was trying to set clear, i totally agree with you, and if we go to:

http://www.rbproducts.com/rbww/pipe_...foldlength.htm

It tells you how to measure that lenght, and in their pipe product description it tells you the min. and max. lenght suggested for each pipe. But what Modellor and I are trying to explain is that on the pipe's designed size by itself, Longer = Top end, Shorter = Torque.

AFM
afm is offline   Reply With Quote
Old 01-06-2004, 10:19 PM   #38
Tech Master
 
x_man's Avatar
 
Join Date: Jun 2003
Location: Planet X
Posts: 1,861
Default

Quote:
Originally posted by afm
Manticore, that's what I was trying to set clear, i totally agree with you, and if we go to:

http://www.rbproducts.com/rbww/pipe_...foldlength.htm

It tells you how to measure that lenght, and in their pipe product description it tells you the min. and max. lenght suggested for each pipe. But what Modellor and I are trying to explain is that on the pipe's designed size by itself, Longer = Top end, Shorter = Torque.

AFM
I thought it was the other way round, where longer pipe will gives more resonating volume, lower resonating time(lower pitch sound) and backpressure, shorter pipe will have less resonating volume higher resonating time(higher pitch sound) and less backpressure hence better reving engine(top end).
These pipes of course, that i am comparing are with the same stinger outlet diameter.
x_man is offline   Reply With Quote
Old 01-07-2004, 12:25 AM   #39
Tech Fanatic
 
Join Date: Mar 2003
Posts: 783
Default

Quote:
Originally posted by afm
But what Modellor and I are trying to explain is that on the pipe's designed size by itself, Longer = Top end, Shorter = Torque.

AFM
I thin you were addressing to the divergent cone shape.
So maybe you can not state it longer and shorter (pipe length terms), just different language problem i guess.
GoldFinger is offline   Reply With Quote
Old 01-07-2004, 05:54 AM   #40
afm
Tech Master
 
afm's Avatar
 
Join Date: Nov 2003
Location: lima-peru
Posts: 1,807
Default

Quote:
Originally posted by x_man
I thought it was the other way round, where longer pipe will gives more resonating volume, lower resonating time(lower pitch sound) and backpressure, shorter pipe will have less resonating volume higher resonating time(higher pitch sound) and less backpressure hence better reving engine(top end).
These pipes of course, that i am comparing are with the same stinger outlet diameter.
For everybodys benefit go to the following web pages, which in my modest opinion have the most complete explanation on Tuned pipes. Eventhough they are from planes and boats, the theory is the same for all 2 storke engines. After reading them things will be as clear as water.

http://www.bolly.com.au/book/Book.js...er=6&Section=1
http://www.hpt-sport.com/direct.htm (go to pipes)

Hope it helps

AFM
afm is offline   Reply With Quote
Old 01-07-2004, 06:17 AM   #41
afm
Tech Master
 
afm's Avatar
 
Join Date: Nov 2003
Location: lima-peru
Posts: 1,807
Default

Quote:
Originally posted by GoldFinger
I thin you were addressing to the divergent cone shape.
So maybe you can not state it longer and shorter (pipe length terms), just different language problem i guess.
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
afm is offline   Reply With Quote
Old 01-07-2004, 09:32 AM   #42
Tech Elite
 
EdwardN's Avatar
 
Join Date: May 2003
Location: SoCal
Posts: 2,144
Trader Rating: 1 (100%+)
Default

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).

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.
__________________
DISCLAIMER: Since 90% of my posts may be BS, and since my posts may be either insanely idiotic, incoherent, and/or not even close to a rational thought, please accord my posts no more than 10% of credibility.
EdwardN is offline   Reply With Quote
Old 01-07-2004, 09:49 AM   #43
Tech Master
 
modellor's Avatar
 
Join Date: Aug 2002
Location: Northern Ireland
Posts: 1,447
Default

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

Sorry everyone.
modellor is offline   Reply With Quote
Old 01-07-2004, 10:10 AM   #44
afm
Tech Master
 
afm's Avatar
 
Join Date: Nov 2003
Location: lima-peru
Posts: 1,807
Default

Quote:
Originally posted by Top Gun 777
.......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 kick in later at higher RPM range will give us much higher top RPM level, but engine first has to reach that level 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).

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.
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
afm is offline   Reply With Quote
Old 01-07-2004, 10:38 AM   #45
Tech Elite
 
EdwardN's Avatar
 
Join Date: May 2003
Location: SoCal
Posts: 2,144
Trader Rating: 1 (100%+)
Default

Quote:
Originally posted by afm
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.
Agree with you 100%.
I am talking about length of tuned pipe ( total lenght) wich is dictating by RPM of our engines ( applications).
Over the years Tuned ( Resonance) pipe went through whole type of development and reshaping. In 70's pipes looked very thin and very long cons, hole on the stinger was arround 8.5-9 mm, Later was add middle straight piece, which actualy gave a lot of more benefits, later it start getting fatter and cons became shorter, stinger hole was going smaller too-7mm-6mm. etc. So the whole evolution came through the development. What we have now is lates best possible, but still lenght of the pipe dictate when charging porcess will began ( poweer add). Shape was chaging to improve efficiency. On the beggining it was adding 5-8 %, later 10-15 and now is about 18up to 25%. Now on control line speed models ( .15 engine) stinger size is 4.5 mm. much slmaller then we have on our RC cars. Those pipes are working on only one way-highest possible RPM during the fly, so not everything frome those designs can be apply to our application, but I am sure some of them easy wilol work ( right now experimenting on it too). BTW, I saw new Mugen pipe on Robby Collins car-that is blasting pipe.

AFM
__________________
DISCLAIMER: Since 90% of my posts may be BS, and since my posts may be either insanely idiotic, incoherent, and/or not even close to a rational thought, please accord my posts no more than 10% of credibility.
EdwardN is offline   Reply With Quote
Reply

Similar Threads
Thread Thread Starter Forum Replies Last Post
engine mods rjmods.net Web Links 2 12-22-2006 01:54 AM
Engine Mods Jammin'Trey Onroad Nitro Engine Zone 116 11-01-2006 05:45 PM
ENGINE MODS? zrchobbies Electric Off-Road 11 08-29-2006 02:21 AM
Need some help with engine mods...... jamiekulhanek Onroad Nitro Engine Zone 6 08-22-2004 11:23 AM
F/S or F/T - Kyosho V1R with RB X12 engine and mods dg2b R/C Items: For Sale/Trade 0 02-21-2003 06:41 PM



Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are Off



All times are GMT -7. It is currently 02:46 PM.


Powered By: vBulletin v3.9.2.1
Privacy Policy | Terms of Use | Advertise Content © 2001-2011 RCTech.net