Engine Porting
 

Ok i have been in the hobby for a long time and i know a lot but im always looking to learn more about rc
so im asking does anyone know any tips about porting a engine i know a lot about doing it but i would like to learn more
thanks

RE: Engine Porting
 

yes with engine porting you will use fuel quicker, the engine will lose accleration at low speed, it will have slightly higher rpm tho and a bit more on top end

RE: Engine Porting
 

no thats is wrong i have my RB S5 modded buy RBMods and that thing can last about 3min longer runtime and has lot more bottom end and top end you have to know what kind of mod to do

RE: Engine Porting
 

no accleration is decreased due to the enigne repsone being slowed down

RE: Engine Porting
 

ok i dont need help anymore because ill im getting is bull from person

RE: Engine Porting
 

cossie you have absolutlyno idea what you are talking about so stop giving wrong info.

RE: Engine Porting
 

cossie you have absolutly no idea what you are talking about so stop giving wrong info.

RE: Engine Porting
 

It is not unusual after you do a sucessful port job on an engine that you increased the fuel flow into the motor making it run slightly richer, so you need to retune the engine, a little bit leaner. After you have retune the motor it should be super responsive, unless you have really messed up the mod. As far as modifying your engine yourself don't do it if you can't afford to waste several piston & sleeves while you are developing skills with your dremel, leave the modifying to the pro's.

RE: Engine Porting
 

Doing a porting job can drastically change your engine's powerband characteristics. IMO, it's one of the most advanced things you can do in the gas r/c world. Most people don't do it right and they won't admit they did it wrong, much less realize they did.

From what i've heard, hand modified engines from people who know what they're doing tend to be VERY good engine and a night and day difference from stock. I wouldn't recommend anyone doing a porting job unless you have EXTENSIVE knowledge of how the engine works as well as the right equipment to do it. Also, be prepared to scrap the engine if it doesn't run properly.

RE: Engine Porting
 

:D
The whole idea behind porting is to round any sharp edges on the sleeve ports. Rounding sharp edges will allow fuel and air to move into the combustion chamber more effeciently. consequently porting the exhust port will allow the spent gasses to leave the combustion chamber more effeciently also. It must be done very carefully so as not to remove to much metal. If to much is removed it will screw up the sleeve and if a rough spot is left it will cause a scuff or a scratch on the piston causeing a loss of compression. :D I hope this will set ya all straight . Good luck:D

RE: Engine Porting
 

True engine porting has to do with both timing and fuel delivery. Quality engine porters can make a night and day difference between stock and hand modified engines. That's why they will do circles around stock engines and still manage to have better fuel economy. Also in some cases the powerband's characteristic can be drastically changed depending on the application, you might want more torque, or just a real peaky top end.

If all you want is to put more fuel in the engine, don't ever wonder why your fuel economy sucks.

RE: Engine Porting
 

i ported my trx pro .15 and that thing is way better than before but ill try it with engines that have cheap pistons and sleeves

RE: Engine Porting
 

well if porting doesnt slow down engine response then go and tell that to all the guys at mines the tuners of the mines skyline, which they didnt port so accleration and engine response would be quicker which killed the amuse super by 4 seconds on the track which had being ported and had more hp

RE: Engine Porting
 

Sure Whatever cossie. Can you explain that again easier to understand.
If you want to learn how to port an engine, there was an article a long time ago in RCCA magazine.

RE: Engine Porting
 

A skyline runs a 4 stroke engine with a turbo...it's not even close to the same as our little 2 stroke engines.. The person who ported the mine's engine probably had a lot of years in engine building and had the necessary equipment to do it right. All these people "porting" their engines just use a dremel and a DIY article.

AND, The reason why the Supra lost so bad was because it was obviously having trouble laying the power down, and it didn't help the LSD was blown or it was 2wd while the skyline was 4wd. If the LSD was still good, it'd of been interesting, but the skyline probably still would have won, just not as bad.

RE: Engine Porting
 

the skyline was not ported though

RE: Engine Porting
 

Still doesn't change the price of beans in anchorage alaska.

RE: Engine Porting
 

Sleeve porting considerations:
Power band requirements will dictate the optimal port timing. High RPM corresponds with high ports.
• Pipe design is crucial to working with port timing. A narrow power band can use a pipe that makes high peak torque values and longer port durations are possible. A wide power band demands a less aggressive pipe and requires lower ports to work suitably.
• Exhaust port durations are the key timing factor to determine first. Regardless of pipe, the exhaust timing will establish the first reference point in time or ratio for the events to occur. Transfer ports are secondary due to the design of the pipe, and variables from pressure in the crankcase.
• Blowdown time is the next factor to consider in timing. The higher the RPM, the more time is needed, and the less time is available for the transfers to pass air/fuel in. Again, the pipe and crankcase pressure will determine the minimum blowdown for a given RPM.
• The above stated, Transfer timing can be adjusted with more flexibility when tuning factors such as crankcase pressure and pipe design. More is better in this case up to a point where blowdown is compromised at higher RPM.
• Aiming the flow can become a critical factor in power. Roof and wall angles have a “sweet spot” where the flow is balanced to provide the best input pattern avoiding excess losses out the exhaust.
Transfer Port Air Flow:

Twin streams of incoming charge emerge from twin transfer ports flanking the exhaust port, and angle back across the piston crown and slightly upward, joining into a single stream at a point approximately two-thirds of the way back from the exhaust port. This stream is deflected upward by the rear cylinder wall, and then it sweeps up to the top of the cylinder to be directed back down the forward cylinder wall-moving the residual exhaust gases out of the exhaust port as it advances in that direction. There is some turbulence generated by this activity, which is unfortunate because turbulence promotes the very kind of churning and mixing that should be avoided. But the turbulence is minimized when the flow is symmetrical, and there will therefore be less dilution of the fresh charge trapped in the cylinder at exhaust-port closing. Skewing either transfer port to one side, or lifting the upper edge of one slightly higher than the other will badly upset the scavenging pattern. Still and despite the fact that high horsepower numbers make good conversation, power range is going to be an extremely important consideration until such time as we have transmissions providing infinitely variable ratios. So the best scavenging system is one that has bulk flow capabilities while maintaining a high degree of flow control.
The proper direction of the scavenging streams is important for reasons beyond the reduction of turbulence and fresh charge/exhaust products mixing. Cylinders need very wide ports to avoid excessive timing durations, which mean that the ports must be crowded together too closely to entirely avoid the dangers of "short-circuiting" the charge. Having a high delivery ratio avails the engine nothing if the mixture streams emerging from its transfer ports are allowed to divert from their intended path and disappear out the exhaust port. This danger increases as the transfer ports are crowded closer to the exhaust port; too, a degree of crowding is almost inevitable. It should be understood that this proximity is acceptable only when determined effort has been made to direct the scavenging streams sharply towards the rear cylinder

RE: Engine Porting
 

Porting a motor can have a dramatic effect on an engines performance. It is not necessarily increasing the port size though. Best of all it adds performance but costs nothing, unless you screw it up in the process.

Porting is just one part of engine modification. With my motors I do usually start with port matching. This matches up the paths in the case with the opening to the ports in the sleeve. Changes can either be done to the case or the sleeve depending on the problem. This almost never means changing the actual size or location of the port face in the sleeve. The port face is the actual surface opening in the chrome inside of the sleeve. Modifications to the brass on the outside of the sleeve are the most common.

Then modifing the path that the air fuel mixture travels around the sleeve is second. Thinning out the area at the bottom of the sleeve where the air/fuel mix travels from inside the sleeve around the bottom then up into the ports, and finally into the combustion area.

Then lastly changing the exterior shape of the port to increase port volume, and or increase air/fuel mix velocity.

The last holly grail of engine modification is working with the engine timing and overall port surface volume. This can provide the most gain in engine power, specifically the duration of intake timing.

You can see in this picture how the bottom of the sleeve has been thinned out to gases to move around it faster, and also the groove that has been cut into the edge of the port to increase port volume, while increasing the speed though which gas will pass when entering the combustion chamber. If the entire face of the port had been thinned out the velocity of the gasses would have been decreased and even though the port was larger less gas would flow through it due to the decrease in velocity. Darn can't seem to get the pic uploaded

Rick RBMods