Hello All.
Jay Stewart here.
I would like to thank everyone from me and Hal to those of you who have purchased a ZIPPER BIG BORE KIT. A few over 50 Kits world wide now. I've enjoyed the posts. Instead of jumping in, there has always been a great reply to those with statements or questions probably better than me so I've been quiet. For anyone who really knows me that's close to impossible. I'm a Sales guy but the Kit has proved it's worth all by itself. I will not sell you something you don't NEED or don't WANT. BUT, if you are in NEED of high hour Cylinder rework or just Want more POWER and ZIP for you flying experience, you WANT and NEED a ZIPPER BIG BORE KIT.
So yesterday, Solo with half tanks, 8000DA, 5139 Field elevation. I have a Kitfox Classic 4-1200 Standard Configuration, with the 114HP ZIPPER CYLINDER KIT. Here's a picture of my EIS showing 15FPM Climb and three witnesses on the radio asking what was under the hood, a Hemi? Very impressive take off. LOL! NO! A ZIPPER BIG BORE KIT on my Rotax Engine.
You won't be disappointed.
Thank you again.
Jay Stewart 7753882046.
Oh! How could I forget to mention a GREAT 72" GA Three Blade Nickel Edge Taper Tip Warp Drive Propeller. Set at 12.5 Deg., Gives me 5400RPMs take off, 5200RPMs CHEAP Entertaining Cruise and 6150RPMs flat out WOT.
Jbird.
Oh! And another BTW I'm building a new Engine shortly with our NEW ZIPPER CAMSHAFT which will give me 120HP. A little more breathing relief for the other moving parts to the added HORSE POW! POW! POWER!
JBird
Thanks for the great info. I fly a Model 4-1200 on amphib floats with an 80 hp 912 and an IVO IFA prop, and overall am really happy with performance even with those two 14 ft long 230 lb floats hanging under it. But I've been thinking more and more about putting the Zipper kit in my 80 hp 912ul.
Am I correct that your 15 FPM means 1500 fpm? Did you see a much shorter takeoff and higher cruise? If so, how significant was it (I'm assuming you had an 80 hp 912 originally?).
Oh, and because you now have a high compression engine, are you burning avgas or premium autofuel?
Hate to say this, but the Zipper kit almost sounds too good to be true. Sorry for being so blunt, but to see a 34 hp gain (42% increase in power?) is pretty amazing.
Oh, and a question I've always wondered, if the 912uls requires a seperate airbox to get it from 95 hp to the factories claim of a hundred hp, how much are we losing on the other 912 if we just use filters off the back of the carbs? Has Hal taken any of that into account on his Zipper testing?
Paul,
I'm with Larry on this. My (flying) plane, which is a RANS S7 had the 95 HP Extra-Performance pistons in it when i purchased it. I installed the Zipper 105 HP kit due to not wanting to spend the extra money on an HD starter and a slipper clutch. These two items were suggested to be added to the engine if I wanted to go to the 115 HP kit. I also liked the idea of being able to use 87 oct. auto gas if needed. I use 91 oct. non-ethanol but I know how difficult is is to get once you travel outside of the corn belt. I'll save that crap for another discussion!
I noticed a considerable difference in performance after the piston/cylinder install. Had to add a couple of degrees in the pitch of my 75" Whirlwind STOL prop to use the additional power. I am happy with the kit and I would think you would welcome the additional power when on floats. Actually I have a set of the ugly Full Lotus floats with retractable gear for my plane, just haven't had the time to install them. I live in float country paradise and wish I had kept my Champ on floats. No beter flying in the world!!
Larry, thank you for the offer to ride in Mangy fox. That would be cool. I am curious about how that huge prince prop works, but almost wish you had a "more normal" prop on it for comparison, as I've heard some pretty marvelous things about the big Prince, even with a stock 912. I'll give you a call one of these days.
WWHUNTER, based on what you and Larry are telling me it sounds like I should just do it. I wouldn't mind going right to the 115 hp, but like you I might not want to mess around with the starter and gearbox, as going from 80 hp to 105 hp is already a huge power gain of more than 30%. I almost can't imagine that on my Model 4, especially if I continue to use my IVO IFA prop. But then again, one can never have enough power on a floatplane... and speaking of floatplanes, that Rans on FL floats would be a blast in MN, as you could leave them on all year. The FL floats work really well as skis in the winter. Oh, and even though the old Champs were great airplanes, you'd love the performance of that Rans (or better yet a Kitfox) on floats. They literally will fly circles around the old antiques on floats.
TahoeTim, I hadn't thought about the fact that the stroke is the same between the 912ul and the 912uls, but that certainly does explain well why the ul sees such a significant gain. In addition to my Kitfox, I also have a newer 912uls in my Highlander with the HD starter along with the slipper clutch, so maybe since I have amphibs for that one too, I should consider the 115 kit for that one as well? I'd be spending a few bucks for sure to do 2 planes with 912 Zipper Kit, but when considering the gain in power it really is a pretty good bag for the buck.
I had Hal install the big bore two weeks ago. I gained 280 RPM static went from 5,400 to 5,680 ground roll shortend by about 100 ft. climb out gained 150 FT. per minute. Cruise stayed the same. I did not change the pitch on the prop, wanted to get a good comparison. Fuel 4.6 gal per hr. same as before. Going to the hanger this mourning to put more pith in the prop to see how it performs. I have the same prop as Jay. I have the high power kit.
I have a 2003 KitFox Series 7 the heavy duty starter will not clear the engine mount. We pulled the engine thinking it would work, it was to long. The stock starter spins it over just fine. But it may not when it gets cold. KitFox changed the mount later on to allow the heavy Duty starter to fit. I have the new mount ordered and plan to install when the weather turns cold.
I'm going to sell the pistons and cylinder we removed from my 912ULS. Hal says they fit the 912 UL. They are in perfect condition 512 hrs. Comes with instructions. !,000 plus shipping.
Hope this information helps. John
Re: 912 Big Bore
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