still4given

Hi Bob or Dub,

I have a couple of Magnum 52 engines. I'm wondering if you guys make a tuned pipe for this engine. It turns pretty good R's with it's stock muffler. I thinking in might really run with a good exhaust system.

Thanks, Terry

bob27s

My Feedback: (19)

Yes, certainly.....

You want to use the standard OS/TT Jett-Stream 40-60 size muffler.

Basically the same muffler you have on the Jett engine, just drilled for the correct muffler bolt spacing.

The Mag 52 really enjoys the tuned exhaust. The engine turns quite nicely

Bob

still4given

Hi Bob,

Thanks for the quick response. I was going through my box of old parts and found one of the full length tuned pipes I used to run on my YS 45. How do the full length pipes compare to the Jett pipes in performance? Maybe I should try this first.

Thanks, Terry

bob27s

My Feedback: (19)

A full pipe will almost always give you more power boost. Not a great deal more, probably another 200-300 rpm on average. Their advantage is you can tune for a specific rpm and torque curve. Set the pipe shorter for more rpm with smaller props, or longer and turn bigger props slower (up to a point). The Jett mufflers are fixed geometry with a know rpm range... you select props that match the engine rpm to that range.

Disadvantage of a full pipe is you have to tune the system to match the application.

Chances are if the header and pipe were already cut to length and setup for the YS45. Just bolt it on, and start with a 10x6 prop. See how the engine behaves and the measure what rpm it turns. Then go up one prop size, and down one prop size. See how the engine behaves.

For existing pipe systems or the pre-tuned systems, I usually recommend prop selection for tuning - just like with the jett muffler.

Example - If you go up a prop size, and the engine holds similar rpm and behaves/needles/transitions well - the pipe was set "too long" for the 10x6. In which case, leave it set there and run the bigger prop - or another prop that turns the same rpm. If you find the engine struggles, is tempermental, then the bigger prop is too much load, the engine cant get on the pipe properly - pipe is considered too short. In which case, you drop back a prop size.

Bob

still4given

Hi Bob,

Thanks for setting me straight on that. I had to buy a new header to go with the pipe. The old header wouldn't have fit my Magnum anyway, so I guess I'll have to tune it myself. I think I read somewhere to cut the header down 1/4" at a time until you reach the optimal size. I guess that means you have to decide on which prop you want to spin before you start whacking. Do you think shooting for 16,000 on the magnum 52 and a 10x6 prop is too optimistic? I might as well go for best since I have to tune it myself.

Thanks again, Terry

bob27s

My Feedback: (19)

I think that is a reasonable target.....

there is a tuning proceedure on the jett website. Works nicely.

Basically, select the prop you wish to tune for. In your case a 10x6.
For pipe setup, utilized a prop that is one size larger. Say a 10x7 (or a 10x8).

Break in the engine first with a 9x6 on it (if it were new) for at least 20 minutes.

Then install the 10x7

Cut the header 1/4" at a time. Warm up the engine, find peak rpm (briefly), shut the engine down. Repeat.
Keep cutting until the rpm gain is minimal. Then trim 1/8" off of the header each time. Note the rpm.
When the engine ends up no longer gaining rpm, or runs cruddy and drops rpm when trying to find peak... the pipe is now too short for the 10x7. (Don't force it ... if it won't run, richen up and shut it down... dont burn it up)

Pipe is too short as set with that prop. But it turns out that it will be set just about perfect for the 10x6. Install the 10x6, find peak rpm, back off 400-500 rpm from there. That is where you fly it.

Bob