PowerHouse RC Performance

My Feedback: (1)

When I said the compression ratio doesn't change, I was reffering to the static ratio which I clarified. I also stated in a couple different posts that I adjust compression based on the application and need. You keep assuming I don't compensate and I keep telling you there is no specific ratio that an engine has to be compensated to. Again it depends on what you want to accomplish. Sometimes I increase, sometimes I decease and sometimes I don't touch it. As far as squish band, same thing applies, and when I need to make big adjustments, that is what the lathe is for. That's great you are an engineer. I myself have spent years casting, machining, porting, building, dynoing and racing snowmobiles and personal watercraft. I used to work for a company that made their own cylinders, pistons, carbs, pipes and heads from scratch and over those years, I was one of the few people who could design, machine, port, build, dyno, install, setup and tune a sled or ski to compete on the highest level. We have set multiple national and world records with our engines on grass, ice and asphalt. That probably doesn't mean a thing to you guys but that is where I learned a lot of what I do now and I also picked up the ability to apply similar techniques into different areas of mechanical engineering. I also was a crew chief on AH-64 Apache Attack Helicopters and again that may or may not matter to anyone but yet again I learned another form of engineering that I could take and use in my personal watercraft's jet pump because I was able to convert over to hydro dynamics by understanding how a turbine compresses air and made the pump compress water in a more efficient way and increased my average speeds by 7 mph which anyone that has boating experience that speed on water is a lot harder to gain than on land or air. As far as telling people to leave the forum, its a public forum and they have a right to be here. Besides, you have been hinted to leave and you are still here beating a dead horse, so why should they have to leave. It is fine that everyone has their own opinions and the people that have similar backgrounds are probably doing their own work anyway. No worries here, I don't have to prove anything to myself. I am happy with the way I build my engines and so are my many repeat customers so you can try all you want to prove everyone wrong and that's fine. Do what you gotta do if it makes you feel better about yourself. Personally I think 2 or 3 pages of arguing about compression is childish. There are other factors that make an engine run decent, not just compression. It is important and I DO adjust it as needed for the intended application (for those of you that assume I don't) but there are also other contributing factors that allow the engines to perform to a desired level.

lez1troubles

if you want a moded engine just go to AB mods, at least they have been at it for years and have a good rep.

PowerHouse RC Performance

My Feedback: (1)

I have been doing this for years and have a great rep. Just because I am new to RC Universe, doesn't mean I am new to the game. I was simply trying to find another avenue to get some more exposure and so far has worked like a charm. By the way, if you have something to post about a competitor, you should really show some respect for me and Adam and post it where it belongs, in his thread. He is a good guy and I don't think he would want people to hi-jack other theads as he wouldn't want my people to do that to his thread.

SManMTB

Ohhhh... ouch that must hurt.


Yeah being in the armed forces and so on is cool and all, kudos for that but since this is about engine modding it's down to what is actually done.
'Arguing' about compression is as far from childish as it gets when it comes to making power. It's key!

I've modded some stuff with varying results LOL. As for compression I've aimed to adjust trapped compression to about 9:1 as a starting point when exhaust duration have been raised. Higher compression always means more power if you can get away with it. Here is where the squish band comes into play.
If the engine didn't have any squish band at all it would detonate at a much lower compression ratio.

Technical question:

If you raise the exhaust timing, will the pipe need to be made longer or shorter in order to keep peak hp at the same rpm?

PowerHouse RC Performance

My Feedback: (1)

It depends on the overall timing is and what you want to accomplish. Depending on how high you raise the timing, sometimes a shorter pipe will have higher peak numbers but a lower overall average. I tend to go with the longer pipes as I can still get very respectable peak power and rpm while still retaining good overall averages throughout. But like anything, it depends what you prefer and how everything else is laid out.

SManMTB

It has to be made longer but thank you for the answer.

lez1troubles

Hey SManMTB, do you do your own mods?
Mr Mark, do you really think your in the same league as AB MODS, you said you were in the air force working on helicopters(Apache AH64) so why the change to model engines, I'm just wondering because the AH64 has turbine engines doent they? would'nt it have been a better move if you would have gone for tuning(moding) helicopter motors instead of waisting your time on model engines especialy nowdays with the recetion, there are quite a few heli mechanics needed and your talents would be more greatley appreciated if you were in the right field. This is'nt a dig so please doent take it to personal.

bkfamily1

My Feedback: (1)

SMan, were you picked on as a child? If you do not want to buy one of his mods, then don't. The only people in here that have actually used his engines seem to think highly of his work. Until you have first-hand experience with one of his mods, why don't you shut your smart mouth? From your very first post in this thread, you have shown all of us what an argumentative a-hole you are. Several people have tried to subtly say as much, but it does not seem to be getting through your thick skull. Is this easier to understand?

SManMTB

Just backyard modding not for public use. It won't be either unless I have a Dyno.
To get ideas about what different mods do and how pipe shapes and lenghts do I can highly recommend to buy a software called MOTA.
Just search for it. It's

PowerHouse RC Performance

My Feedback: (1)

Good reply! I actually do modify engines of all kinds including fixed and rotary winged aircraft. I don't know Adams background so I can't say who has what but I can definately tell you I can hold my own against the competition. I am into the offroad segment of the model car world because I have been building and racing them for 25 years. I have had an offroad model car since I was 7 years old so it is something I have always been into. That's the biggest reason I like the car engines as well. I didn't take it as a dig so no worries.

SManMTB

If you call discussing engine mods argumentative then you can shove it. It was all basic simple questions.
Talking big is easy, answering simple questions in a clear way is much harder it seems.
Why are you all butt-hurt because of this? It doesn't concern you or your business if you have any.

edit:
Just for the record, please note who starts using personal insults in this thread. [8D]

savagecommander

since were on the technical topic, how do you come to that conclusion?

lez1troubles

Mr Mark, thanks for the quick reply, you've earned my respect for whatever it's worth and I'd like to wish you much succes with your tuning venture. May the power be with you, your a strong man. Good luck.
SManMTB, come on man leave him alone, and thank also to you for the tip. Stay cool dude.

PowerHouse RC Performance

My Feedback: (1)

Thanks buddy! I appreciate it. After 10 years in the service, a combat tour in Iraq and 5 years in law enforcement, not too much bothers me anymore lol.

SManMTB

No problems on this end. [8D]

savagecommander

lez1troubles

Looks like quite alot of us are ex-forces, I'm from the U.K and was with the army for 5 years, been around the world and it was'nt fun. Now I'm going to bed, it's one O'clock over here in Belgium and I would like to watch the U.S open at three, two hours of shut eye. Night night. Be good and piece N love to every one.

SManMTB

Sure no problem.

It has to do with the resonance in the pipe and when the plugging pulse comes back to the exhaust port. When the pipe+engine is in resonance the plugging pulse arives back to the exhaust just before it closes. This happens in a very narrow rpm band.

RPM: 20000 rpm
Pulse speed: 500 m/s
Exhaust #1: 170 deg
Exhaust #2: 180 deg

Exhaust port #1 is aproximately open for 1.42ms. With pulse speed of 500m/s, this gives that the pulse travels 708mm in that time. Remeber the pulse has to travel 2 ways in a pipe giving a pipe length of half that or 354mm.

Exhaust port # is open slightly longer or 1.5ms in this case. The pulse travels 750mm in this time. Divide by 2 and the pipe length is 375mm.

Remember that (perfect) resonance only happens for one length. So by this the pipe needs to be longer for the system to be in resonance at 20000rpm if the exhaust is increased from 170 to 180 deg.

This is the principle.

SLAYERDUDE

And his PC told him so!
Real world testing and years of experience modding race sled 2 strokes has nothing to do with performance.

Just get this and you too can be an expert!
10 easy payments of only $19.95 + tax, shipping and installation!!!

willclark77

My Feedback: (2)

I have a question if you don't mind. When you "add mechanical pinch" back to one, what's the life expectancy compared to an exact but new sleeve? I know it highly depends upon the application, but in general is it roughly the same as a new sleeve, add 50% more run time, just squeezing and hoping...?

SLAYERDUDE

I completely agree with your other post in this thread Will.
Here's a place with good info on pinching, I was starting to work on my own pinching system but decided to go this route because of price and quality.
I have heard many good things.
http://www.rayaracing.com/
If anyone does have a good way of repinching at home I would be very interested.

SManMTB

You really have a problem with facts don't you.
LMAO

If you want to save time and actually learn something it's well spent money. Where is the problem with that?

Oh and, do you always speak to people in third person? To me it looks like you're a dude standing in a field talking about stuff you have absolutely no idea about.

PowerHouse RC Performance

My Feedback: (1)

Ray does all of my pinching and he is one of the best. As far as longevity, that will depend on material quality as it does originally but I have gotten 6-7 gallons on repinched rossi's I normally got 9-10 originally. It will also depend on how you treat it like anything else. The pinch is worth doing for the money especially if everything else looks good inside and you need it to finish the season.

SLAYERDUDE

Ditto.
Except for your field is completely empty.[sm=lol.gif]

SManMTB

No software needed either SLAYERDUDE.

It's easy (for normal people).
In standard units.

Lt = (E x S) / N where;

Lt = tuned length in inches
E = exhaust duration in degrees
S = pulse velocity in ft/s
N = engine speed in rpm.