Pep exhaust question?

[BEN S]

The thread on the mini 500 keeps referring to a "pep" exhaust, that I guess means peppy?
What is it? Does it really work to increase the horsepower and is it a factory authorized rotax part?
And MOST importantly is there one for the 503?
What is the drawback if any, like reduced engine life?
Thanks guys
Ben S

[All_In]

Hi Buddy!

I'm not sure what a PEP exhaust is.
I suspect it is just a tuned exhaust for a certain RPM range.

These folks http://www.paraflite.net/muffler.html advertize "The 503 (dual carb) TUNED muffler brings the 503 from 52 to 62 hp. The price is only $425 plus shipping"

[BEN S]

Oooh Snap!
Don't know if it's hype or not, but for the price if it comes close to the claims I'm getting one!
Anybody know if these are safe for the engine or is it going to fry my 503?

[BEN S]

john, reviews on tuned exhausts not looking good!

[DennisFetters]

Ben, the PEP stands for Performance Enhancement Package, and it will only work on a Rotax 582 and in a helicopter application. I developed it to move the lower end of the power band up to the 90% rage of the rotorsystems operational RPM range, giving you much more torque to recover from a low rotor RPM situation, which was it's primary function and reason of design.

As an added benefit, it stabilized the EGT's so that swapping out the jetting due to density altitude changes was not necessary.

Also as a benefit it increased the overall power from 65hp available to 78hp, which was handy as a boost to get you out of a tight situation, since we didn't increase the gross weight limitation.

It turned the Rotax airplane engine into a helicopter engine, with no ill effects.

[BEN S]

Thank you Dennis,
What do you thnk of this company's claims for the 503? Since you designed one I figure that would make you more than qualified to tell if it's bull or not.
Ben S

[DennisFetters]

Originally Posted by BEN S

Thank you Dennis,
What do you thnk of this company's claims for the 503? Since you designed one I figure that would make you more than qualified to tell if it's bull or not.
Ben S

I couldn't see what company you were referring to. I would be happy to look it over if you provide me the link.

[BEN S]

John posted it on post #2 above, I'd relist it, but I still haven't got this iPad figured out yet!
Ben S

[DennisFetters]

Originally Posted by BEN S

John posted it on post #2 above, I'd relist it, but I still haven't got this iPad figured out yet!
Ben S

Ok, I missed that, I was looking for something you posted.

Well, hard to say since I have no experience with these people, but they are stamped-out sections in the pictures, the way real manufacturers build pipes. That's a good sign.

All the Rotax engines on the bikes and snowmobiles use tuned pipes to get the horsepower. The 582 is a 110hp engine in a snowmobile.... running at 8500 rpm and tuned pipe. For aircraft, Rotax de-rates the engines by lowering the RPM and chocking off the power with the aircraft muffler.

You could get more performance out of the 503 using the tuned pipe, if it's jetted correctly. If you have an oil-pump and don't use mixed fuel and oil, and don't just run the pi$$ out of the engine all the time, I don't think you will have any problems and you would have a significant increase of performance. Jetting correctly is the key.

[BEN S]

I have been doing some reading on the tuning of rotax pipes and the consensus is to leave the engine alone for reliability. I dont need the extra ponies bad enough to possibly fry my engine. The "Proper" jetting seems to be elusive according to the the reviews I am seeing.
Ben S

[All_In]

Hi Buddy!
The problem with internet reviews is you cannot tell the experts from the ???.
I would make some inquires of the company as to how they tested there tuned exhaust and to see a copy of the dyno test over the entire PRM range and I ask how to jet yours for where you fly.

Then for the price (you could resell it) I would test it checking the plugs etc after each flight. As long as I do not see a major difference keep on keep'n on if the power is almost the same as a 582?

PS:
It would answer what it would be like to have a 582 and if it was worth the cost too? Should the exhaust start causing problems.

[BEN S]

Too true my friend,
I get nervous with the whole changing jets thing probably because there is some PFM contained within them!

[Rotor Rooter]

Ben,

The page SynchroLite ~ Exhaust has information related to tuned exhausts.


Dennis is best qualified to say how his PEP [Performance Enhancement Package] differs from the basic tuned exhaust.


This is some information on the Helicycle;
The Helicycle has a tuned exhaust and tuned input. This is similar to the Mini-500 PEP kit. To me, this is being done to increase the maximum power, which intern results in a higher maximum Break Mean Effective Pressure and a higher efficiency. If this increased available power were to be utilized, there will be a reduction in reliability. Perhaps Schramm's thinking is that tuning the engine and then derating it will increase reliability. He was talking about a 500 to 750 hour life.

This paragraph came from BUY: Engine - Reciprocation - 2-stroke.


Hope that this is of some help.

Dave