quote:

ORIGINAL: meef rustler

Throw it in the trash. Trx engines are garbage. Buy an os .18 or a dynamite .19T or something. Those engines are near the size of the Trx 3.3, but way easier to tune and they are not overpriced pieces of trash.

quote:

ORIGINAL: chris6414

Agree, a right at the limit HS will begin to run lean as the tank emties. Same with helos and planes. If the tank lines inside are more than one season old or you have this truck used, then by all means change all the "in tank" lines. A small pin hole inside the tank will begin to suck exhaust gasses if the hole is exposed when the tank begins to empty and lean the mix. Even with a pin hole in the tank, the tank will hold vacuum and pressure as the hole is "in the tank" Those small bubbles may not be seen in the opaque fuel line. If your real lean, then the fuel coming in will begin to vaporize and actually produce pulses of back pressure in the fuel system. As it vaporizes at the hot carb throat, that pressure can push fuel back through the carb further leaning your run or it wil vaporize in the cyclinder too early and mess with the timing of the burn and cause erratic running. I would replace the lines first and see where that gets you. Before the next run go 45 degrees richer on the HS and then tune her back in. Hopefully you get her back to her scalded dog self and shred some turf(or asphalt).

quote:

ORIGINAL: Oacker

The fuel I am running is Sigs, who normally makes airplane fuel, but has a couple different RC car blends too.  This stuff is 50% castor - 50% Klotz synthetic with 10% nitro.
 

quote:

ORIGINAL: nitroexpress

quote:

ORIGINAL: Oacker

The fuel I am running is Sigs, who normally makes airplane fuel, but has a couple different RC car blends too.  This stuff is 50% castor - 50% Klotz synthetic with 10% nitro.
 

Sounds like you are trying to run Champion "10".  A good airplane fuel, but inappropriate for car engines.  20% total lubrication is way too high.  And why cheap out with the 10% nitro level? 

quote:

ORIGINAL: Oacker

quote:

ORIGINAL: nitroexpress

quote:

ORIGINAL: Oacker

The fuel I am running is Sigs, who normally makes airplane fuel, but has a couple different RC car blends too.  This stuff is 50% castor - 50% Klotz synthetic with 10% nitro.
 

Sounds like you are trying to run Champion ''10''.  A good airplane fuel, but inappropriate for car engines.  20% total lubrication is way too high.  And why cheap out with the 10% nitro level? 

I've seen people go round and round about the oil content, and I just don't care to do it.  Granted, I am CHEAP, thus I buy inexpensive fuel... but there are too many red herrings in this hobby if you ask me.  The bottom line is airplane fuel is not all that different than car fuel aside from marketing and a couple percent more or less oil.  To the professional racer there is probably a difference... to the back yard basher, I doubt it.   I have had terrific luck with this inexpensive fuel (not necessarily low quality fuel thought)  thus far... no issues with wear inside the engine - crank rod and sleeve are all good.  I did have to replace the rear bearing which is common in the 3.3, but have had no issues since replacing it.  After almost 5 gallons I did a re pinch on the sleeve to bring the compression and performance back up to like new.  Also, no issues with tuning until now. 

For what it's worth, my brother in law's revo is running traxxas top fuel 20%... he swears my revo is faster with the 10% nitro, though I can't tell the difference myself.  This is not to say there are no other mitigating factors that would cause this scenario to play out, ie tuning, piston/sleeve fit, etc etc. 

I did run a half a tank of traxxas fuel through recently just to check if my fuel was the issue and i basically had the same results just at different needle settings.

Well, I said I wasn't going to do it, but as far as oil content goes... one thing I will say is that it makes sense to run  higher total oil content with lower nitro content.  From what I understand, nitro brings additional oxygen to the combustion cycle, thus allowing for more fuel to be entered into each combustion stroke which generates more power.  With a lower nitro content, you have less fuel going through each combustion cycle... in order to keep the VOLUME of oil the same through each stroke, you would need then a higher total oil percent.  What exactly these ratios are I do not know.  All I know is that I have run this fuel in two different 3.3's without issue.  Tuning is definitely different... but once it's tuned your good to go.  All that said... I do not think 20% oil content is necessary, though I personally dont see a problem with it.  Heck, isn't traxxas fuel like 17 or 18%? 

At this point I am just going to run the engine.  I was able to keep it below 270 last night bashing about pretty hard, mostly in the 240 range, so I'm good.  It may not be running perfectly, but again I'm not racing... just bashing about.  

cheers.

quote:

ORIGINAL: proanti1

quote:

ORIGINAL: Oacker

quote:

ORIGINAL: nitroexpress

quote:

ORIGINAL: Oacker

The fuel I am running is Sigs, who normally makes airplane fuel, but has a couple different RC car blends too.  This stuff is 50% castor - 50% Klotz synthetic with 10% nitro.
 

Sounds like you are trying to run Champion ''10''.  A good airplane fuel, but inappropriate for car engines.  20% total lubrication is way too high.  And why cheap out with the 10% nitro level? 

I've seen people go round and round about the oil content, and I just don't care to do it.  Granted, I am CHEAP, thus I buy inexpensive fuel... but there are too many red herrings in this hobby if you ask me.  The bottom line is airplane fuel is not all that different than car fuel aside from marketing and a couple percent more or less oil.  To the professional racer there is probably a difference... to the back yard basher, I doubt it.   I have had terrific luck with this inexpensive fuel (not necessarily low quality fuel thought)  thus far... no issues with wear inside the engine - crank rod and sleeve are all good.  I did have to replace the rear bearing which is common in the 3.3, but have had no issues since replacing it.  After almost 5 gallons I did a re pinch on the sleeve to bring the compression and performance back up to like new.  Also, no issues with tuning until now. 

For what it's worth, my brother in law's revo is running traxxas top fuel 20%... he swears my revo is faster with the 10% nitro, though I can't tell the difference myself.  This is not to say there are no other mitigating factors that would cause this scenario to play out, ie tuning, piston/sleeve fit, etc etc. 

I did run a half a tank of traxxas fuel through recently just to check if my fuel was the issue and i basically had the same results just at different needle settings.

Well, I said I wasn't going to do it, but as far as oil content goes... one thing I will say is that it makes sense to run  higher total oil content with lower nitro content.  From what I understand, nitro brings additional oxygen to the combustion cycle, thus allowing for more fuel to be entered into each combustion stroke which generates more power.  With a lower nitro content, you have less fuel going through each combustion cycle... in order to keep the VOLUME of oil the same through each stroke, you would need then a higher total oil percent.  What exactly these ratios are I do not know.  All I know is that I have run this fuel in two different 3.3's without issue.  Tuning is definitely different... but once it's tuned your good to go.  All that said... I do not think 20% oil content is necessary, though I personally dont see a problem with it.  Heck, isn't traxxas fuel like 17 or 18%? 

At this point I am just going to run the engine.  I was able to keep it below 270 last night bashing about pretty hard, mostly in the 240 range, so I'm good.  It may not be running perfectly, but again I'm not racing... just bashing about.  

cheers.

20% oil content is WAY too high, especially for car engines. Plane engines run a lot cooler due to a prop being right in front of them. The parts never heat up enough to expand, so the extra oil is needed. Same is true for boats. An oil content that high in a car leads to pre-ignition, overheating, and crappy idle, they are just not designed for it. 18% is the max you should ever run in a car, which is still too high IMO. Traxxas Fuel is 16%. O'Donnell Race is 7% synthetic, which is what I run.

quote:

ORIGINAL: Oacker

UPDATE:

After days and days of fighting with this tuning issue... wasting fuel, scratching my head, and getting frustrated... I just slowed down for a minute and figured I must be missing something.  Something simple - and that I need to start from scratch.  I disassembled the engine completely and VOILA!! 

Sure enough... it was something simple that I completely overlooked.  There was a chunk missing from the seal on engine's front bearing causing an air leak.  I swapped front bearings and all is now well with the world... engine tunes perfectly and runs just like I remember. 

Cheers.

quote:

ORIGINAL: savagecommander

quote:

ORIGINAL: Oacker

UPDATE:

After days and days of fighting with this tuning issue... wasting fuel, scratching my head, and getting frustrated... I just slowed down for a minute and figured I must be missing something.  Something simple - and that I need to start from scratch.  I disassembled the engine completely and VOILA!! 

Sure enough... it was something simple that I completely overlooked.  There was a chunk missing from the seal on engine's front bearing causing an air leak.  I swapped front bearings and all is now well with the world... engine tunes perfectly and runs just like I remember. 

Cheers.

isnt the contrast between what people tell you could be wrong and what is actually wrong astonishing?

20% fuel is a bity slobbery, but the higher rpm the motor is run the leaner it gets, and the only thing protecting it is the oil. i had probably the equivalent of 200,000 miles on an old ninja .27, but the crank bushing was still tight and the piston couldnt be pushed out the top when i went to rebuild it- so i always run high oil content.

quote:

ORIGINAL: supertib

quote:

ORIGINAL: savagecommander

quote:

ORIGINAL: Oacker

UPDATE:

After days and days of fighting with this tuning issue... wasting fuel, scratching my head, and getting frustrated... I just slowed down for a minute and figured I must be missing something.  Something simple - and that I need to start from scratch.  I disassembled the engine completely and VOILA!! 

Sure enough... it was something simple that I completely overlooked.  There was a chunk missing from the seal on engine's front bearing causing an air leak.  I swapped front bearings and all is now well with the world... engine tunes perfectly and runs just like I remember. 

Cheers.

isnt the contrast between what people tell you could be wrong and what is actually wrong astonishing?

20% fuel is a bity slobbery, but the higher rpm the motor is run the leaner it gets, and the only thing protecting it is the oil. i had probably the equivalent of 200,000 miles on an old ninja .27, but the crank bushing was still tight and the piston couldnt be pushed out the top when i went to rebuild it- so i always run high oil content.

I call total BS that you had a Ninja .27 !

quote:

ORIGINAL: savagecommander

quote:

ORIGINAL: supertib

quote:

ORIGINAL: savagecommander

quote:

ORIGINAL: Oacker

UPDATE:

After days and days of fighting with this tuning issue... wasting fuel, scratching my head, and getting frustrated... I just slowed down for a minute and figured I must be missing something.  Something simple - and that I need to start from scratch.  I disassembled the engine completely and VOILA!! 

Sure enough... it was something simple that I completely overlooked.  There was a chunk missing from the seal on engine's front bearing causing an air leak.  I swapped front bearings and all is now well with the world... engine tunes perfectly and runs just like I remember. 

Cheers.

isnt the contrast between what people tell you could be wrong and what is actually wrong astonishing?

20% fuel is a bity slobbery, but the higher rpm the motor is run the leaner it gets, and the only thing protecting it is the oil. i had probably the equivalent of 200,000 miles on an old ninja .27, but the crank bushing was still tight and the piston couldnt be pushed out the top when i went to rebuild it- so i always run high oil content.

I call total BS that you had a Ninja .27 !

I'll go ahead and take this oppurtunity to do something you've never done to one of my questions- answer it directly.

now that i think about it, the motor may have been a .21- blue heat sink with a silver body, but i think i can remember the ''.27'' etched onto the top of the sink. either way it was a scalding hot mill, but it was some time ago. i have since sold that motor,along with many others. i stuck it in a buggy chassis and i could not find a spur small enough to labor the motor any so i turned it into a muggy or truggy or whatever.... * it had big tires* ...ran that motor hard on some 16% stuff everybody told me not to, with a mcoy #8, but it ran all the way up to when i sold it- probably about eight gallons.

any other questions you'd like me to answer kneel?