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-   -   Conversion to Gas? (http://www.rcuniverse.com/forum/engine-conversions-92/8196438-conversion-gas.html)

Merlin Man 11-29-2008 11:45 PM

Conversion to Gas?
 

Hi,
I have a SuperTigre G4500 Glow Engine ( 45 cc ) and I have heard the these can be converted to Spark/gas.


I was wondering if any one has heard of this conversion, how much it might cost and whether or not it is successful.


Any info would be appreciated.

Cheers,

Merlin Man.

oldtimer2 11-30-2008 12:04 AM

RE: Conversion to Gas?
 
Hi, Try this web site: http://www.airpowertechnologies.net/APT_Services.html they advertise conversions for Mokis & Super tigers.

Ram Jet 11-30-2008 01:06 AM

RE: Conversion to Gas?
 
I suspect your engine will produce more power but run MUCH hotter and the opportunity for your gasoline falling upon a hot exhaust causing a fire would be greater. My father had a methanol burning open wheel dirt track race car years ago and I bugged him constantly to attempt to run it on gasoline There are more BTUs of heat produced from gasoline than alcohol per unit of weight). It should have produced more power. He finally gave in, changed the carburetor jetting (leaner) and yes, the engine produced more power. Unfotunately, it also onverheated and the engine temperature exceeded the capacity of the cooling system which was designed for alcohol. I think your engine is a two cycle and may benifit from additional cooling fins on the head or a heat sink. If it's a four cycle I doubet your exhaust valve and seat will survive.

Bill

av8tor1977 11-30-2008 01:45 AM

RE: Conversion to Gas?
 
Yes, gasoline has more BTU's than alcohol. However, the correct mixture for methanol is twice that of gasoline. Therefore, even though methanol has less power potential unit for unit than gas, you are burning twice as much and therefore make MORE power not less. The inherent cooling effect of methanol in the inlet tract further increases power. And lastly, if an engine is purpose designed to run methanol, it can be built with a higher compression ratio, which increases power further yet.

Methanol powered engines make more power than gasoline.

The problem with your Super Tiger engine is that it will need to be converted to a roller bearing on the rod so as not to have to run so much oil in your fuel. Super Tiger recommends 10% oil in their large engines, while normal gasoline engines run from 2 to 3%. If you ran 10% oil in a gasoline setup, you would probably encounter problems with carboning up the engine.

AV8TOR

Starfighter 11-30-2008 04:40 AM

RE: Conversion to Gas?
 
Hi. My name is Ken Wilson (Starfighter).

Have converted both a ST 2500, and a OS BGX to gas. Both used a Walbro carb and CH ignitions. Both engines run FINE, w/o the problems alluded to by others. Any engine will overheat if not properly cooled, and the gas conversion does not increase the potential for this occurrence. (The ST 2500 turns an 18 x 8 prop @7850rpm using gas. Sold the BGX.)
* You DO NOT need to convert the engine to a roller bearing. You do have to run 10% oil with the gas because the engines do not have roller bearings, but no problem, and NO problems with any carbon bulid up. Use a high quality oil.
* You do not need to use a Walbro carb with the ST 4500, or the OS BGX as the stock carbs will meter gas with proper adjustment w/o problem. If using stock carb, get the Cline pump/regulator, or a Perry to ensure consistent fuel pressure as you cannot use muffler pressure when using gas.

The cost is reasonable for the ignitions, and the results are satisfying.

Another suggestion: The ST on ignition using FAI fuel (80% Methanol, 20% oil) is a MONSTER. Truly a BEAST in power output, even better than running gas/ignition. This option combines the reliability of ignition, with the use of a familiar fuel.

This is my opinion, and it is based on years of experience (modeler for 50yrs., flying R/C for 40yrs.). I rarely respond to these posts, and only when I can provide correct information.

Charley 11-30-2008 09:44 AM

RE: Conversion to Gas?
 
Apt site is interesting. Know anybody who uses their products?

CR

Charley 11-30-2008 09:57 AM

RE: Conversion to Gas?
 
Quote:

ORIGINAL: Starfighter

Hi. My name is Ken Wilson (Starfighter).

If using stock carb, get the Cline pump/regulator, or a Perry to ensure consistent fuel pressure as you cannot use muffler pressure when using gas.
Hi Ken,

I ran a Saito 1.5 on gas with the stock carb one summer. Was able to use muffler pressure by putting a short piece of silicone tubing from the muffler to a filter and Tygon from the filter to the tank.

Quote:

Another suggestion: The ST on ignition using FAI fuel (80% Methanol, 20% oil) is a MONSTER. Truly a BEAST in power output, even better than running gas/ignition. This option combines the reliability of ignition, with the use of a familiar fuel.
Does the big Tiger need 20% oil with methanol? I thought it was a lower percentage but I'll bow to experience every time.

Quote:

This is my opinion, and it is based on years of experience (modeler for 50yrs., flying R/C for 40yrs.). I rarely respond to these posts, and only when I can provide correct information.
I ran 16:1 gas to oil mix in the Saito. It did run hotter than on 5% glow fuel and power was down around 200 RPM but that was negligible to me. I had a shim under the jug, however. Never did run it on gas without the shim.

I have a ST 3000 with CH ignition. Was thinking of running it on gas. Do you think the 16:1 mix would be OK?

TIA,

CR

Merlin Man 11-30-2008 04:40 PM

RE: Conversion to Gas?
 
Hi All,

Wow! Thanks to all for this great feedback.

Starfighter, your answer provides a good deal of positive info and I was wondering if you would recommend any particular Ignition unit ?

I have sent an email to the website you mentioned Oldtimer 2 and am looking forward to their reply.

Thanks again,
Cheers,
Keith Knowles, (Merlin Man ) Australia.

the mother of invention 12-03-2008 02:15 PM

RE: Conversion to Gas?
 
You don't have to convert anything on the big Tigers. Run E85 from the gas station at 1.99 a gallon and put in 12-18% oil depending on the model you have. The S2000,2500 and 3000 run on 18% oil (15% synthetic 3% castor) and the S2300, 4500 run on 12% oil (10% synthetic 2% castor). Just change your glow plug to an OS F and it will run like a top even inverted without on board glow driver. It is the best fuel for you Super Tigers. I have been running this and checking head and exhaust temp with laser thermometer and with that mix the temps are identical to glow fuel.

Starfighter 12-03-2008 03:26 PM

RE: Conversion to Gas?
 
Hi. Just read the forum again.

Re. preferred ignition unit: I use the CH Ignition unit (aluminum case) and the RCExl by CH Ignition w/o problems. I also recommend the units sold by RC Extreme Power, (Milton Thompson). These are excellent as well (suspect they are RCExl too.). You can find both on the Web, and here @ RCU.

Re. the comment about using muffler pressure w/gas: I have to say that while it worked, if the tubing ever fails and raw gas hits the hot muffler... well I hope you have a fire extinguisher handy. You'll need it.

Re. the comment about less oil in the FAI fuel: Yes, you can run straight FAI, or a less oil mix (approx. 12%). I recommend that you run a synthetic oil FAI fuel, no castor. A great synthetic is Klotz Techniplate.

I hope this helps, and good luck with the engine.

Ken (Starfighter)




Starfighter 12-03-2008 03:51 PM

RE: Conversion to Gas?
 
Hi Charley:

Re. the 16 to 1 mix for Gas: Yep, that's a good mix to use. You will not damage the engine at all. Just make sure that you do not run it lean, OK?

Ken (Starfighter)

captinjohn 12-03-2008 08:32 PM

RE: Conversion to Gas?
 

Quote:

ORIGINAL: Starfighter

Hi. My name is Ken Wilson (Starfighter).

Have converted both a ST 2500, and a OS BGX to gas. Both used a Walbro carb and CH ignitions. Both engines run FINE, w/o the problems alluded to by others. Any engine will overheat if not properly cooled, and the gas conversion does not increase the potential for this occurrence. (The ST 2500 turns an 18 x 8 prop @7850rpm using gas. Sold the BGX.)
* You DO NOT need to convert the engine to a roller bearing. You do have to run 10% oil with the gas because the engines do not have roller bearings, but no problem, and NO problems with any carbon bulid up. Use a high quality oil.
* You do not need to use a Walbro carb with the ST 4500, or the OS BGX as the stock carbs will meter gas with proper adjustment w/o problem. If using stock carb, get the Cline pump/regulator, or a Perry to ensure consistent fuel pressure as you cannot use muffler pressure when using gas.

The cost is reasonable for the ignitions, and the results are satisfying.

Another suggestion: The ST on ignition using FAI fuel (80% Methanol, 20% oil) is a MONSTER. Truly a BEAST in power output, even better than running gas/ignition. This option combines the reliability of ignition, with the use of a familiar fuel.

This is my opinion, and it is based on years of experience (modeler for 50yrs., flying R/C for 40yrs.). I rarely respond to these posts, and only when I can provide correct information.
I have a SuperTiger .90 that I am going to run on ignition. I will have 2 fuels to try and will run first test with 20% oil and 80% methanol , then less than 5 minuets later I will run it on 20% oil (Klotz) with 80% gas. Capt,n

aatorix 12-06-2008 08:29 AM

RE: Conversion to Gas?
 
Merlin Man Do I understand you to say that you can essentially put gas in the tank for a ST 2300 and go ???? I mean I know you gotta change tubing and stuff but that seems too good to be true, and you know what daddy said about that. No spark plug, no ignition, no worry about timing and such ??? I must have mis-read.

captinjohn 12-06-2008 09:26 AM

RE: Conversion to Gas?
 

Quote:

ORIGINAL: aatorix

Merlin Man Do I understand you to say that you can essentially put gas in the tank for a ST 2300 and go ???? I mean I know you gotta change tubing and stuff but that seems too good to be true, and you know what daddy said about that. No spark plug, no ignition, no worry about timing and such ??? I must have mis-read.
aatorix, If you read the entire thread you will get a better picture of what can be done in a SuperTiger 2300. The rod does not have to be converted to needle bearings as long as you use 20% oil in the gas. More oil gives more power as you have a better piston seal. Now AV8TOR gave a idea that too much carbon would build up using high amounts of oil. As long as you use oils like Kltotz that will not happen. Bottom line is yes you can run the S.T. 2300 by just adding a CD ignition and using 20% oil. Like with any engine avoid lean running, drop your top RPM about 200 RPM with HI-speed needle. Best Regards Capt,n;)

tkg 12-06-2008 10:55 AM

RE: Conversion to Gas?
 
A 2300 will run fine on 10% oil, the 90 ST will need 15% or more

captinjohn 12-06-2008 04:16 PM

RE: Conversion to Gas?
 

Quote:

ORIGINAL: tkg

A 2300 will run fine on 10% oil, the 90 ST will need 15% or more
TKG Thanks for the hint. I was going to start at 20% on the Supertiger .90 on gas/ignition. Maybe 18% is whe I will start. Thats using Klotz oil. Best Regards Capt,n;) P.S. Right now we just got 18 inches of snow...and they say 6 more inches to come. No testing engines

tkg 12-06-2008 09:55 PM

RE: Conversion to Gas?
 
Quote:

ORIGINAL: captinjohn


Quote:

ORIGINAL: tkg

A 2300 will run fine on 10% oil, the 90 ST will need 15% or more
P.S. Right now we just got 18 inches of snow...and they say 6 more inches to come. No testing engines
Wimp, our test stand for the 40cc plus engines is out side. You haven't lived until you stood in the prop blast of a 150cc twin when its 0 outside.

captinjohn 12-06-2008 10:44 PM

RE: Conversion to Gas?
 

Quote:

ORIGINAL: tkg

Quote:

ORIGINAL: captinjohn


Quote:

ORIGINAL: tkg

A 2300 will run fine on 10% oil, the 90 ST will need 15% or more
P.S. Right now we just got 18 inches of snow...and they say 6 more inches to come. No testing engines
Wimp, our test stand for the 40cc plus engines is out side. You haven't lived until you stood in the prop blast of a 150cc twin when its 0 outside.

I have had enough cold just today removing lots of snow and taking care of the Husky dogs. They love the snow and I have seem them sleep on snow in a blizzard when they could be in the Igloos I bought them. Go figure! Best Regards Capt,n[:-]

Merlin Man 12-10-2008 05:30 AM

RE: Conversion to Gas?
 

Hi,

I have just revisited this thread after a week or so and am amazed about the post by Mother of Invention regarding the use of E85. ( that's not to say that all the other posts haven't been informative and helpful ...they have and thanks very much )

I have not heard of this fuel E85. I guess that it may be Petrol with 85% ethanol ?? Is this it ?

I don't know for sure if we can get this mix here in Australia ? ( We have 10% Ethanol at Petrol Stations ... so far ? ) However, it may be available and if so I would like to know if anyone else knows of this and how well it works ?

This would certainly be the easiest "conversion" ever if all you have to do is change to this fuel, use an OS F plug and adjust the oil as you have stated.

M of Invention, does the ST 45000 give the same power as on glow fuel ?.... don't you have to change the fuel tubing ? ...... Do you run exhaust pressure ??

Thanks in advance,
Cheers,
Merlin Man.

aatorix 12-10-2008 08:56 AM

RE: Conversion to Gas?
 
Man, this thread is so fascinating as I have never done nor seen a gas conversion after 20 years in the hobby. I gotta try it. Are there any step by step guidelines or instructions on converting to gas / ignition ? The piece about just running a big ST just by putting gas and oil in it is unbelievable to me. Couldn't be simpler. How do you measure the oil percentages mentioned ? Thanks to everyone who has taken the time to answer my dumb questions. I'm thinking now about a ST 90 conversion. I have written to APT at this writing. No rersponse yet. Thank you.

foresterxt 12-12-2008 02:28 PM

RE: Conversion to Gas?
 
Quick question, where are you guys finding the clamp style hall sensor mounts (look like a hose clamp). Are they for sale our does everyone just make their own?

Thanks,

Dave


av8tor1977 12-12-2008 03:35 PM

RE: Conversion to Gas?
 
www.ch-ignitions.com

AV8TOR

foresterxt 12-12-2008 05:26 PM

RE: Conversion to Gas?
 

Quote:

ORIGINAL: av8tor1977

www.ch-ignitions.com

AV8TOR

Perfect! Thank you.

Merlin Man 10-09-2009 06:08 PM

RE: Conversion to Gas?
 

Hi All,

Well, it's nearly 12 months since this post was active and I have resumed my idea of converting the Supertiger 4500 to a cheaper fuel.

I was not able to persevere with the questions on using E85 with 12% oil as suggested by Mother of Invention.


I am still very interested in this idea ( since it seems sooo simple apart from anything else ! )


Quote:



Date 12/4/2008 5:15 AM

You don't have to convert anything on the big Tigers. Run E85 from the gas station at 1.99 a gallon and put in 12-18% oil depending on the model you have. The S2000,2500 and 3000 run on 18% oil (15% synthetic 3% castor) and the S2300, 4500 run on 12% oil (10% synthetic 2% castor). Just change your glow plug to an OS F and it will run like a top even inverted without on board glow driver. It is the best fuel for you Super Tigers. I have been running this and checking head and exhaust temp with laser thermometer and with that mix the temps are identical to glow fuel.




Does anyone know if there is any fither info re this type of "conversion" ?

Cheers,
Merlin Man.

av8tor1977 10-09-2009 06:25 PM

RE: Conversion to Gas?
 
You can certainly convert it... The trick is whether you want to convert it to run on less oil as well. You can just buy an ignition from, for example www.ch-ignitions.com and run it on a mix of gasoline and 12% oil. If you want to lower it's oil requirment as well, that takes more work. You have to change the rod bearing from a bushing to a roller bearing. For this, search info from Ken Lambert. Here's his website: http://lambertsrc.homestead.com/

Good luck,
AV8TOR


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