1QwkSport2.5r

Yeah, I hear ya there. I like my engines to rev, so that's why I haven't converted any of them yet. Someday I'll run one or two on diesel.

eddieC

My Feedback: (2)

Just TELL your club members that you're ordering a batch buy and, if they want in, the order closes on xx/xx/2013/14.
We order ours so as to pick it up at Toledo, have been using Ritch's Brew lately but have used Red Max and others. They can make almost any blend you can think of; 2-stroke, 4-stroke, FAI, etc. You might want to add $1 per gallon for handling to cover the gas for whoever is picking it up. You will save plenty on your fuel doing this! I haven't bought LHS fuel in decades.

fujiman

My Feedback: (133)

HELP!!!!!!! Ok all you super tigre experts, I have been looking in-vain for 3 super tigre s90k engine gasket sets. I want to lower the compression with an extra head gasket on 3 of my engines. Any ideas where the heck I can find some, have tried every place I could think of that possibly had any. A real bad thing happened when super tigre sold to China, no parts and VERY bad service for sure!!!!!!!!! If any of you guys know a source please post here or PM me with info. Thanks, fujiman

1QwkSport2.5r

Some guys cut their own with a super sharp hobby knife and cut an aluminum soda can apart. But why would you want to lower the compression ratio? Would you rather be burning 10-15% nitro versus 5%?

jeffie8696

Check with Great Planes service department.

aspeed

I make my own shims rather than wait forever for mail, and shipping services and fees. I use a compass with a knife on it. It scores it and then you fold it back and forth until it pops apart. Anything over .005" is kind of hard, and it isn't easy to get a close tolerance. Actually any brand shim will work with the same piston bore.

fujiman

My Feedback: (133)

Thanks guys for all your help and suggestions!!!!!!! I'm trying to lower compression on my Italian Super Tigre 90's so I'm able to use a little more nitro in the fuel instead of buying several nitro content fuels. I have been successful in lowering the compression on some of my Fox Hawks .60's which are over compressed also. I found that ST .51 head gasket/shim fit perfectly. It's rather difficult to match up head gaskets with other brands of engines because sizes aren't always given. If any of you guys know what brand of eng. shims would work please reply. Your vast knowledge and experience always comes thru!!!!!!! Thanks, fujiman

AGNI 5

Italian ST G20/23,stored for like 3 years. It was recently commissioned in a 2 metre pattern plane. started immediately on the application of the starter. Checked for idle and it was near perfect flight. 5% nitro fuel and OS F plug. Those who still own the Italian ST hang on to them. Why ? Recently I had a need for a .40 and naturally selected a ST but unfortunately the are all CHIN. COM made. All the years I have never run in a ST on the , they were fitted on the model and flown. The CHIn made is nowhere the quality of the Italian job. No compression out of the box and will not start without application of the starter ,after some one litre of fuel there was some improvement. Hand starting was still dicey.( Subsequent starts with the G20/23 was reverse flip and the motor is mounted inverted).If the CHIN .com made ST go out of production nothing to worry about. Hope production will resume in Italy or in another country where people have pride in their workmanship.

aspeed

If you look up similar motors online, they will have the bore and stroke shown on many motors. The bore is usually given first and will be the inside diameter if the shim. If the outside diameter is too big it is easy to cut with scissors and good glasses to see better.... As far as the chinese motors are concerned, I don't think they are that bad, although all of mine are Italian. My old G.15 didn't even have a tapered bore, so they weren't perfect either. Any other civilized country will be much more expensive to manufacture and buy, and it would be a hard sell.

hsukaria

I've owned a Chinese G51 for 7 years and has seen the highest usage of all my engines. It has been a super reliable and dependable engine. I believe it is due for a new piston ring now. I switched from 15% down to 5% nitro and that helped solve the throttle transition from being sloppy rich. I don't know how it compares to the Italian G51, but it has been excellent for me. But now I don't see even the G51 offered for sale anymore, as mentioned previously. It might be better to get the G45 anyway since they are true ABC and cheaper.

Regarding the shimming to use higher nitro, I would bring all the other engines down to 5% nitro instead of raising some engines to higher nitro for cost savings. The only 2-stroke I have not re-tuned to lower nitro is an OS 55AX. I use the 4-stroke fuel blend for it, and 5% nitro for all the other 2-strokes with good results. I would try re-tuning the OS 55 to 5% nitro, but it is installed in an Ultimate biplane that cannot tolerate dead-sticks and I can't guarantee that I won't get a deadstick during the re-tuning process.

tshirtmeister

Anyone running a Twin 60? I have two and lookin for the right plane. I havefrom the twin 60s to G34 rc and everything in between. Go SuperTigre

1QwkSport2.5r

Italian G51 with Bowman ring and 5% nitro - 10,800rpm on a APC 13x4W after 30 minutes of break-in of the new ring. Smaller props it ran right with my TT Pro .46. Hand starting or backflip starts with 1 quart of fuel after new piston ring. Picks up 450+rpm with the use of a flat spraybar from an S90. No experience with the Chinese ones, but I'm fine with that.

The liner of the Chinese version is slightly smaller than the Italian liners bore. Each version has its own size piston ring according to Frank Bowman.

The stock ST rings are rather hard and thus the lengthy break-in needed for them to behave. Throttle transition is always rich until the ring is bedded in really well. About the same as Enya and Fox. For the patient, they are a wonderful engine. For the guys that want ABN out of the box performance, stay away from ST.

hsukaria

Why would the flat spraybar increase RPMs that much? Is it narrower and increases flow area?

1QwkSport2.5r

Yes. I have pictures somewhere of the two spraybars. The G51 round spraybar would be shaved down at least 1/3 its diameter opening up the choke area by a good margin.

Edit: without any modifications other than using the S90 spraybar and needle I got a 450rpm gain on a 10x6 APC prop. Sorry I misspoke in my last post. The ring isn't seated all the way so it needs more time to find the definitive difference. I will do this in the spring when it gets warmer. 450rpm is a chunk of extra power for making such a small change in the setup.

hsukaria

But if you open up the venturi, you will have less suction from the carb. That might impact throttle response of fuel draw from the tank. That might be ok on the bench, but might affect you on a plane when doing stunts.

1QwkSport2.5r

While this may be true, I doubt it will have that much impact on fuel draw. The Venturi of the carb is already pretty small, so the area of the spraybar being opened up shouldn't impact draw much. The bore of my G51 carb is slightly smaller than the carb on my TT Pro .46 so it should be fine. Opening up the Venturi itself may pose an issue if combined with a shaved spraybar. I'll test it all out and post my results in the tach forum when I get to it.

hsukaria

that should interesting info.

aspeed

If you feel real industrious, you could run a control line needle valve and no venturi at all. Then you could see the real limit of the motor. You would need pressure, either a bladder or backplate pressure. I found huge differences in some motors like the Norvel .15 and AP and ASP .15, and almost no difference in the LA .15. I guess the breathing of the bypasses and other variables make the change worthwhile or not, at the expense of throttle response and sensitivity.

Hobbsy

My Feedback: (102)

Here ya go.

hsukaria

Wow!! That is a huge difference. How do I go about getting one of those flat spraybars?

1QwkSport2.5r

Get Italian carb parts. I haven't seen any pictures of a China made carb with a flat spraybar. Since some of these ST parts are hard to find, I'm going to use a carbide cutter in my dremel and shave it down to the same spec as the flat spraybar. The cats eye can use some work to make the discharge orifice more condusive to atomizing fuel better too.

1QwkSport2.5r

Hsukaria - here's a NOS flat spraybar. http://www.ebay.com/itm/141169267543?nav=SEARCH&sbk=1

hsukaria

Put a bid on it. Now guys, don't fight me for it, I am serious about getting this part!!!

1QwkSport2.5r

I put it on my watch list.

Hobbsy

My Feedback: (102)

HS, the SuperTigre 4500 carb and the 2300 carb have a similar set up, the 4500 has the thin sprabar. For Diesel conversion of the 4500 I just use a 2300 carb. It's a perfect match. It's a cool way to make a carb larger or smaller depending on your need.