912 Big Bore

[BigJohn]

Have 6.5hrs on the New Test Engine (Named 1622 Big Torque Zipper) Amazing performance thus far. Ended up pitching Prop 1.5 degrees over Stock 912 ULS seeing an increased climb VY 400-500 greater than stock. Seeing increased TAS of additional 10-12mph. Still able to climb at 500' min at over 14000'. No increases in CHT, Oil Temp or Water temp, 4000' hard climb VX today showed max water temp 203. Max Oil & CHT temp 194.

I make no income from these Engins only a Tester to test performance, I will report all findings Good, Bad or Ugly.

Contact on these engines are as follows:

Sales,
Jay Stewart. 775-388-2046
Wayne Flemington (Southland Rotax. S.Ca)951-255-9144

Technical,
Hal Stockman 775-934-5714
Wayne Flemington 951-255-9144

Units available and proven presently:All are Bolt on to 912ul or 912uls

1484 Zipper High Torque 105hp
1484 Zipper High Power 114hp

[BigJohn]

Total of 10.1hrs
Oil consumption is near non existent last 3 hrs,
Increased needle Jet to 2.76 and Main Jet to 176
This produced lower EGT' down here near sea level and provided needed fuel air mixture which is now calculating HP at just over 120hp
Will most likely settle in on a main jet of around 172 once warmer weather moves in during summer. Time will tell, CHT' are lower than stock engine but I did some cowl modifications which I contribute this to however the larger more powerful engine is not causing any heating issues, Hard climb and high cruise are never over 206.

[BigJohn]

13.2hrs on the new Conversion and all is checking out very good, Good CHT's, never above 209 even in hard Climb, EGT's are within normal operating and Oil is staying below 200. The climbs in relation to the regular group I fly with is significantly better than when stock and out climbing all that I had been flying with , Top speed has increased as previously mentioned. The innitial Climbout fuel consumption is up as would be expected with the needed larger Jets whoever when flying with the group at our regular cruise speeds I am 200rpm lower than before and after leaning with the Hackman still keeping EGT's within average ranges I am burning approx 3.2gph, this is at a slower cruise of approx 98mph. I am leaving on a short trip out of state on family business so won't be flying or testing anymore after today until mid April. Will report more then after more hours.

[BigJohn]

Just returned from my trip and back in the Air, now have 17.5 hrs on the engine and it shows no negative signs, oil consumption is minimal at 4 oz in the past 7hrs, EGT's on climb out are in the 1300's with cruise in low to mid 1400's at sea level to 3000'. Fuel burn on climb with larger jets is approx 9.5 with cruise around 5.5, However with leaning from Hackman the cruise fuel burn at 3000' msl is below 4.0. If I pull back to Eco at approx 55% power I am at 3.2 on consumption.

I have been tweaking on the Carbs and lowered the needle jets one notch. And find this setting works better down near sea level will be doing high altitude testing this next week.

I am overly pleased with the engines performance thus far, This engine was originally tested new prior to breaking with 160 main jets and tested out at 115hp on Dyno, I am confident with larger jets and now some hrs on it that it is more than that HP , I calculate it with fuel burn and RPM' to be around 120HP.
I have been flying with another plane with a stock 912uls and a plane with the 1484 Zipper High Torque 105 hp and find the Zipper 105hp far superior to the stock 912uls, I am extremely impressed with this conversion.

[BigJohn]

Update on the Testing of the 1622 Big Torque Zipper Big Bore Conversion for the Rotax 912 Engines.

Just over 20hrs and have all the Jet Settings working great, Currently using a Mid Range Jet of 2.76 and a Main Jet of 176, The Niddle Pin Setting is in the Middle, All is running great and very well balanced. EGT Temps are in the Upper 1300's on full throttle climb and increase to low to mid 1400's once pulled back to a cruise of around 5200 RPM, Leaning brings the Egt's into Balance in the Mid 1400's and lowers the fuel burn at Cruise down to around 4gph. Cht's and Water are holding around 200 on a full climb.

I did high altitude testing today and with leaning on the climb saw innitial Climb RPM at 5570 as altitude increased Leaning was required and never dropped below 5420 upto 18000 msl. Still had a climb rate of 270 to 300' min at 18000'. If I took out the leaning the RPM dropped to around 5180 still significant at that altitude. With Leaning on Straight and Level flight at 18000' I could get 5600 RPM with Leaning (Hackman). The best I had ever seen with the stock 912 was 15,600' once in the winter in the middle of Oregon and ran out of climb rate. Several times at around 14,000' I would run out of climb ability with the stock 912 100hp.

I will be testing different Props in the near future to see the effects. Currently using a 70" Warp 3 Blade.

I have no Negatives to report on this Conversion but there are plenty of Positives.

[WWhunter]

BigJohn,
I realize all your posts on here are for the largest displacement engine but I would like to know if the other guys that are flying the 105 h.p. versions have accumalated data like you have? I have a 1996 year engine I am thinking of putting the 105 h.p. kit on. I would prefer the 115 h.p. but the cost of everything needed is more than I can afford.

[BigJohn]

I fly on a continual basis with an individual that flys a Pelican PL I have flown this plane several times myself with a stock 80hp Rotax and now with the 105hp conversion, I can say that it is a different plane, He was able to out perform me in my stock 100hp when he had two on board and I had just myself, the plane now performs just under mine with the Big Bore by about 150 RPM, The compression is 9.7-1 so still low compression for Big Bore. I know he see's at least another400+ ft min climb, he is swinging a 72" Warp and the performance change is nothing less than fantastic. He has had to increase his Main Jet to a 170 but with warmer weather setting in looks like he will probably go down to a 165. He has not done all of the performance testing due mostly to experience but the time I have flown it shows standard oil temps of around 195 with virtually no oil consumption, water and CHT temps in the 180's, His EGT' have always shown high 1400's to low 1500's with both engines even with larger jets however the probes I feel are located to far down the exhaust pipes which could impact accurate readings. He currently has around 70hrs on the conversion with no issues. Fuel burn on cruise is under 4gal.Hr with the Hackman Leaner.

The 1484 High Torque 105hp Zipper Conversion is an excellent choice and I would strongly recommend for any one with the stock 80hp. Biggest Bang for the Buck.

[Av8r3400]

Exactly what kind of bucks are we bangin' here?

[WWhunter]

BIG BUCKS!!!

Speaking to Hal a month ago I figured it was going to cost me an additional $2,000+ to be able to upgrade to the high compression kit verses the high torque kit. I don't have the list available but the 115 HP kit will need a high torque starter, possibly an upgrade in the gear box, and a couple other items I can't recall right off the top of my head. I figured it would end up costing me $7,000+ if I went with the 115HP kit. Whereas the 105HP should run me around $5,000. This is still alot of money to gain 10HP. I have mentioned in an earlier post that I have the Extra-Performance high compression pistons in my engine already for a (hopeful) 95 HP over the stock 80 HP output. That comes out to roughly $500/HP gain over what I already have.
My thoughts were that I could just sell my 200 hour TT engine for a fair amount and invest that money plus the $7K into a NEW 912iS or a turbo'd 914. Granted I would have more money invested but I would also have a NEW warrantied motor with all the current updates.
Food for thought.

[BigJohn]

Exactly what kind of bucks are we bangin' here?

105hp 1484cc. 9.7-1 is $4200.00. Parts. Or $5,000 parts and install and would not need HD Staeter or gearbox slipper clutch. This is a Bolt on kit.

114hp 1484cc. 11-1 is $4300.00 Parts. Or $5100.00 parts and install and it recommended to have HD Starter and slipper clutch. This is a Bolt on kit.

115+ 1622cc 10.5-1 is $10,000. Installed and requires machining of Case and Heads. You have to send Hal your engine he tears down and back up, you may insure additional parts expense if items are found that need replacing.

I would recommend any to call Wayne or Hal for technical questions or Jay or Wayne for sales or pricing. I don't have anything to do with either, Just testing and reporting what I find and do. Phone numbers are on Mar 10 posting.