Have anyone tried to do any modification to model engine and turn ASP into Saito?

The intend is not to make a fast engine faster, a good engine better, but trying get a slower engine to decent performance, all in the lights of getting the best bang of the buck..! At a low risk of course.

Please share your experience and advice. Thanks

umm, that is about as likely as turning a 2 stroke OS into a 4 stroke YS. they are different engines, the parts are different, and even if there is ANY overlap of common parts, it isn't a single part that makes it perform like a saito, it is the entire engine. besides, an asp 70 is closest to an os 70, not a saito.

besides, have you looked at the price of individual parts? it won't take long before you are WAY over the cost of the better engine anyway.

Hi Smoke,

My term of modification is not inter-changing of parts but more like lightening the piston, upgrade bearings and drill, bore, tap whatever possible to make the engine runs better...etc..

Different break-in procedure...etc...

Changing of parts can also be part of it like, use a saito exhaust on a ASP or using 70size exhaust on 52 size engine...etc...

Try it and let us know how it turns out.

Usually, the manufactures spend a lot of money and effort into developement of any given engine, but I guess there is always room for improvement.

doubledee

AB:

All the hop-up methods that work on the engine in your car will work on the model four stroke engines. The problem is that most have been incorporated in production.

You can get some improvement by cleaning the ports for better air flow, but not a lot. The cam profiles are already about as radical as you want, go wilder and the idle goes to pot.

You can't raise the rpm safely, as the parts aren't designed for it, and your max rpm, if you don't worry about overloading the rest of the engine, is limited by valve float.

It's best, if you want more power from a 4s engine, just to buy a more powerful 4s engine.

Bill.

I agree with Bill.

You could replace the ring with one that is lapped flat to seat better on the piston land, hone the cylinder, adjust the ring end gap, polish the ports and lap the valves with a water base compound.

It would a a lot easier to buy a more powerful engine and do the above when it is worn out to bring it back to life

That's our main advantage... we can install just about any engine we want in our planes... so hopping an engine up is not an economical option... unless your main objective is to hop up that engine

Guys, guys,,,

We would like to hear ideas, new, fresh out of the box thinking. Sure, I can go end buy a YS 140.... But,,, what about making a Magnum 91 perform way better? What about the personal satisfaction from acheving the objective.

I would like to know results from a person that has tried.

By the way: Hope this tread does not disapear in to oblivion, two week ago I tried with one regarding the modification of the can gear.

Bill,

If the piston was too big for the bore, you could always file the crown of the piston a bit, then hammer it into the cylinder. Then nail the head back on if the threads don't match.

-David C.

The point has been made...
What do you define as "better"...? More power?
The engines on the market today do exactly hat they are supposed to do.
It is not impossible to get a Magnum .91 to perform like a 1.20... powerwise... but there is a trade in... that trade in is user friendlyness...


Four strokes are no different from two strokes... there are .91 two strokes with 2 hp and there are .91 two strokes with 5 hp.... which one would fly your plane best you think?