Engine Mods
 

I just started getting interested in engine modifacations i have seen a couple of people doing the engine modifacation to the crank and other places. i just wanted to know if anyone could point me in the right direction(how to's)(and do not's) Websites and pictures will be very helpful, thanx

Re: Engine Mods
 

I will try to get web links for you where you can find very valuble info to understand engine, will posted later.

Read R/C Car Action February 2004.There is some information.

Goto the RCzone on rccaraction website and talk to "MaverickRacer" He's very, very knowledgable (sp?) about modifying nitro engines. He also mods engines for alot of people and apparently is very good.

The first thing to do before starting modding is to learn what actually happens inside an engine and what characteristic each modification has.

This link is a favourite with a lot of people to learn more about engines and modding. It is primarily about RC boats but the same principles are applied to cars also.

http://rcboat.com/past.htm

There is no point watching someone modding an engine and then trying to recreate what they did. For one you dont really know why you made the change and that particular change may not suit your requirements. Different changes can be needed for different tracks (depending on whether you just need out and out speed, really low end punch or a mixture of both).

Re: Engine Mods
 

Agree with Modeller. If you will just copy what people does, you will be always "chasing the tail" It is much better to understand how engines are designed and build, what is impacting their beheyvior, what events are following each others and then try to improve one or other thing in chain of events.
Here is web links will help you in some way:
http://www.bmaps.net/info/pipes.html
This is one of my favorit article and without understanding this events you can't do any modding-poilishing and porting will not make anydiffernce: http://www.control-line-team.de/moto...echnik_en.html
http://members.bellatlantic.net/~vze2p5sj/engine4.htm
http://rcboat.com/anttech.htm
http://www.rc-sa.co.za/engine.htm
http://geocities.com/CapeCanaveral/G...67man_pipe.htm
I hope these web links will help you and some other guys to understand engine's designs and find your way to work with engines.
Good luck in modding and if you have questions please feel free to ask, I will be happy to help.
Edward

thanx for all your responses very!!!!!!!!!!!!!!!!!!!Helpful!!!!!!!!!

Those were very detailed articles on boat engines, and combat airplane engines, but where are the ones about CAR engines? Specifically on tuned pipes and stuff on cars.

It's not about cars, planes or boats, it's about how engines in general work.

Once you understand that you can come up with the mods you need.

I'm no engine guru to start with.
 

I'm still learning the trick of the trade and would like to share any information that I can find thru the internet .Hopefully someone who understand better can help to explain certain topics.OK I start with crankshaft balance .

Some notes on crank balance:

If you want to get fussy, and allow for the port being moved, balance on a "wheel" type balancer. This can even help on a stock type crank. (see some of the Russian engines, .15 size for examples). The amount of counterbalance needs to be in the 50~65% range of the weight of the piston,wrist-pin,(ring, if used) and 1/2 the weight of the rod. To test this, measure the weight of the reciprocating parts on a good gram scale, and make up bob-weights in this amount to add to the crankpin, before you put it on the balancer.The crankpin should "stop" at the 12 O'clock position. On a single cylinder engine: If you add weight to the counterbalance, or lighten the reciprocating weight. you DECREASE the PRIMARY shaking imbalance (vertical= Cyl. bore axis), and INCREASE the SECONDARY imbalance (crosswise= across the lugs).
For this reason, IT'S IMPOSSIBLE to balance a single Cylinder engine, without a secondary Balance shaft, as used in some auto engines. Adding weights (heavy slugs) to the counterbalance is done to change the resonant frequency at which you get a "Harmonic" or strong vibration level. You want this at a lower than full rpm number. Most of the ST X-40's used in Formula-1 Pylon and Fast Rat had cranks that needed this changed to resonate in the high-teens (RPM). Sometimes you could see the engine "shake" in this range, on the test stand. I never put a strobe light on one to see what one would look like while running. If the engine is balanced to "resonate" at full RPM, IT USUALLY COMES APART

Again some one might be able to eleborate this further.
Thanks

I am 100% agree with Stefan. What is the difference between RC cars engines and other type engines. Actualy nothing. Every application required adjustment of varibles ( timing, balancing, pipe length etc). General principals are totaly the same.
In Pipe wise, just can tell you, in air modeling and boating is use single period resonance tuned pipe and in RC cars ( due to the car's sizes) it is two period ( two cycle), means you need to devide all varibles in half ( lenght etc). Single cycle pipe is much more efficient and when pipe kicks in it sounds as exploded "bomb". I have tryed my boat's .15 pipe on car -it was amesing, but it was hanging out of body like cucumber ( 6 inches) and it is totaly illigal. LOL, but was working realy great.
But because it is, two period pipes, we need to take to concidiration-wave is loosing its power on second return ( when most charge happened), so our goal is to save power of that second return wave as much as possible. If it is loose it will not be that efficient.
So here is thing to think about ( and make experiments).
:nod:

Re: I'm no engine guru to start with.
 

Hey very interesting point. Somewhere of the beginning of my present here in forum I mentioned about dynamic balance ( but someone call me irrogant idiot for it). This is what about. In many cases we just think about static balance ( when we work with engine on working table) try to weighing piston wrist pin and conrod. But when engine is working specialy at high RPM we have place dynamic balance, when wight are shifting from one position to other. In my opinion there can be real solution to get rid of unbalnce and made balance perfect. but there is ways to decrease it a lot.
Here in your post is mentioning some Russian engines with uncommon design of the shaft, it is absolutly tru. We can move some part of engine to one or other side which will help us to fight with this problem. On my new upcomming engine, I am using this trik- I have moved induction port to one of the side. We did it always in the past, no one Russian engine has induction port on the center. This design been use sometimes from mid 1980's
It is impossible to use the same way of improvement on existing common RC cars engines ( one of the point why I decided to make my own device). I am not saying existing engines are bad, I just think about this problem differently.:nod:

Re: Re: I'm no engine guru to start with.
 

Thanks TG for your response.You mentioned that you move the induction port to one of the side.Then the transfer and exhaust port timing position do you change that too in relation to your induction port design/position.

Re: Re: Re: I'm no engine guru to start with.
 

I moved induction port to one of the side, I did it phisicaly, but induction timing stays where it is designed to be-opening and closing. about timing on exhaust and transfer-I always do alter them to my numbers.;) :nod:
Phisical position and timing-I can move port in any way, but still can keep timing on induction even as stock existing engines. Just dreaming-if I have space under the car for carb-it will be almost ideal situation, but unfortunately we don't have room under car.

OS .12 LD and OS .15 LD
 

Your explaination here reminds me of this OS engine.Unlike most engine now which the piston stroke is in the vertical manner.The OS LD(LayDown) piston stroke moves horizontaly.The carb is on top of crankcase.My point is I believe the induction port position of this engine is different.I have one of this engine and will open it up to confirm.Have you seen this engine or any comments from you?

Re: OS .12 LD and OS .15 LD
 

I haven't seen any of that OS engine, just on OS web site and can't realy tell you if it is the same. But that engine still has the same design as everyone else. The vertical or horizontal position is only metter, how you install on the model. OS have try to install it horizontal to lower down SG, but it is probably dangerouse due to the cooling and it takes a lot of horizontal car space, so most likely it will create car design problem. I don't realy know what else they ( OS ) had in mind to put engine on that position, if they try to move induction port to other position- it was ( in my opinion) right attempt, but again, too many things are together ( car-engine), so probably didn't work ( cooling, car's space etc). THis is why it was just dream to have space under the car.
Also regadless where induction port is located, it designed to have right timing.:nod: Just try to immaging cranck according to that design and you will understand how many benefits can be gain from there.:nod:

You're correct :lol: This engine can only fit into the Kyosho superten FW04.Maybe can also fit into the newer version pure ten FW05.This car design and layout is the same but only different in scale.

OS 12 LD
 

Just checked design on that LD engine-they have moved 90 degree to left side, but again, I have no clue what reason push them to do so. If just follow lei down position, well that means they did it not in porpose,so it will not give any benefit , but if they put engine to that position because of the induction port-again, it was right attempt, but they didn't finished ( for any reason-ley down engine doesn't have enough cooling, so they stop massaging idea).
http://www.osengines.com/parts/ev11170-11540.pdf

WO~WO~WO~WO~WO~

TOO MANY HELPFUL INFORMATION THERE......:lol:

THANKS ALL GUYS!:lol:

Wow, too much secret info was released!!!!:D
HIDE IT!!!!!!!!!!!!!!!!!!!!!!:lol:

TG u got PM
 

fuel consumption and hp
 

guys,

got a question regarding fuel economy. what changes on the engine that will affect fuel usage of an engine the most? assuming all other variables (type of fuel, clutch setting, exhaust system etc.) being the same. trying to balance hp and fuel consumption.

thanks,

data

I would say that the increasing the diameter of the carb opening or boring out the crank would give most increase in fuel consumption. The difference between my RB X12 with a EFRA legal crank and the same engine with a Novarossi T5 crank is about 2 mins worth of run time. With the T5 crank I get approx 5mins 30secs and I constantly ran with the stock crank for well over 7mins 30secs.

Re: fuel consumption and hp
 

Wow, you saw my engine was running by Jose on CP two weekends ago and was there 9 minuts ( three tanks in row), now you are asking what to do? :weird: :sneaky:

Re: Re: fuel consumption and hp
 

damn! ed you never miss a chance do you ? :p no, i didn’t see jose’s run two weeks ago, but i will ask him about it. i actually didn’t ask "what to do", i simply want to know which area affects fuel consumption of the engine the most. so what are you going to tell me, if anything at all ?

didn't find anything r/c under the tree, been a bad boy i guess. got a bottle of smiroff and a bottle of wild turkey thou, bring some martini glasses next time when you come to the track and, you still owe me one bottle.

Re: Re: Re: fuel consumption and hp
 

They're selling to the underage again are they? :lol:


TG,

Remember what you said to me about never keeping info away from the needy? :sneaky: :eek:

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

Hi Evo. And I don't keep info from anybody, I think.
To answer Data question, want to go little bit deeper. Fuel economi is basecaly efficiency of engine. We can produce power by burning all fuel or we can partly use it to cool engine down.
I know we need cool engine or it will overheat. But is there other way arround to cool engine. Many ways are there-right timing on all events, fuel quality, compression ratio etc.
One more realy important thing is carb design too. What I am meaning by that, is what is mixture ratio carb makes at any opening point. We will have much more power output specialy on acceleration if it stays in the same ratio-air/fuel. If you look on the carb-close it and slowly open-you will see when bottom end needle is living spray bar. From the moment when bottom end needle leave spray barour engine is running on top end needle setting, but we tune that needle when air is open completely. What I am talking about is-ones bottom end needle left spray bar, but air not open completely our air fuel mixture ratio is on fuel side ( reach)-this is exactly place where we are loosing run time and acceleration.
I have already moddify couple of carbs and realy happy with that.
Data, do I owe you bottle or to Ah10? :confused: I think I owe to Ah10 ( but can be mistaken):weird: :D

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

TG how do you go about making the bottom end needle leave the spray bar and at the same time the carb is fully open. Thanks

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

Top Gun, I dont think you owe me any alcohol! hehe but I wouldnt mind if you make me a fast 21 engine! hehe

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

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:nod:

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

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?

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.

Sorry, but my experience is that the longer pipe gives you more torque while the shorter on gives more rpm's.

I too thought it was the other way around. :eek:

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

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

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). :weird:
These pipes of course, that i am comparing are with the same stinger outlet diameter. :)

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.

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