kebauc

Quick question, we have a shockwave (great fun), and a major reason for buying it was price. Started out on 20% fuel, but that really eats up the fuel budget after a few gallons. We bought some 5% fuel, and are having a hard time getting the car started. Do we just need a hotter plug?

I am fairly new to nitro, but been around R/C for a while (my first car was an optima mid).

RoadBurner

Different fuel different needle settings, probably just needs to get tuned right.

AllAboutFunHobbies

Go back to 20%, You'll be alot happier and it will run alot better.

TThib

Hhhhmn... 5% is kinda low. Will that even work?

I haven't been around nitro all that long, but I can't remember anyone ever running anything less than 20%.

firebird78

u was prolly runnin it rich with the 20% so it will eat up more fuel...

taylor152806

never ever go lower. just up

rc rock

i think thats way too low...
the lowest i ever run is 16% once or twice a year when i'm low on cash..

Swamp3r

My lhs said if you want to have fun never run lower that 20%.

ranger4x4

yea these guys are right. 20 % minimum. if you do get it to run it probably won't last long before it does some damage. i have heard alot of people say that these engines are designed with 20% in mind.

twomanytoys

If you cant afford the fuel then you are in the wrong hobby. You should be getting a good 12-15 min of run time. 20% is absolute min if you want fun. 5% no mater what you do it will be a terd and really hard to tune. And yes the lower the nitro content the hotter the plug you need.

Kemo

Nitromethane is an oxidizer. You COULD run it, it just wont be as potent as it would be with 20%. You have to use correct shims just right to run correctly. Since it is a much lower nitro %, you are either going to have a lot more oil, or more methanol. You wont do any damage to it unless you know what you are doing.

Too many people consider themselves experts when it comes to fuels... they do not understand what the ingredients in fuel really do.

Cam_132

20%... the engines were made for 20 at the factory... 30 (or 33) could blow your engine

Kemo

LOL... you are incorrect.

Majority of mid quality and lower quality engines come shimmed for 20% nitro from the factory. The higher end engines come shimmed for 30%.

If you run 30% in a engine shimmed for 20%, you will NOT damage your engine. It will not run correctly, and it'll be a pain to tune.

It will NOT blow your engine. Members need to stop making false assumptions. If you do not know for sure, then do NOT type it.

Cam_132

ok i did not know that thank you.

ehroof

To a point he was correct, most engines (especially the redcat engines and thats the forum he is in) come shimmed for 20% and if you do run 30%, you can overheat the engine since if not tuned properly, it can run hotter than 20% and that can ruin the engine, so he was not really wrong in what he was saying

TThib

You learn something new everyday... that is a good thing.

Of course, telling someone they are wrong can be done in a more personable manner... Adds alot more merit to the correct info you are giving.

ehroof

i agree, its not nice to demeen people, this is a help forum i thought

Kemo

No prob.

Nitro is just a fuel oxidizer. Now, if he was running a fuel with less than 10% oil (unless its all caster and no less than 8%), then it would be damaging to the engine. Too much oil can also be a bad thing. Anything higher than 14% is considered too much these days. Since more attention is given to the lower priced engines, high oil fuels are slowly disappearing (in car blends). What happens with too much oil? Overheating can easily happen when trying to dial in the best performance. With more oil, performance generally drops. People tend to tune incorrectly by overly leaning to squeeze out more power. Doing so then damages the engine.

pede_187

very true. . . . and normally the engine won't last as long on 30%

Kemo

Not true... When shimmed correctly it will not shorten engine life.

Chubbysdad

My Feedback: (1)

Very True. I agree with Kemo. If shimmed correctly 30 percent actually can make y our motor run cooler. Thats all i use. byrons gen 2 30 percent.

Redcat Nick

I would say for 80% of the people in here 20% is all they need

kebauc

Thanks for the input Kemo. We did get the engine to turn over a little better today by preheating the engine and using the standard plug. I will have to get a variety of plugs and experiment a little more.

As far as most of the comments are concerned, perhaps I should explain myself a little more. I tend to enjoy my hobbies differently than most people. My full time job is a mechanical engineer, and I take the same approach here. I know the conventional wisdom is to run 20-30% nitro in buggies. I also took the time to compute the exact fuel/air ratio that various nitro % needs. Its really interesting stuff. When I clean up my calculations i may share them.

Kemo

You still have your oil content, that stays the same regardless. The only thing you are sacrificing for the extra nitromethane is methanol.

More power, and about 7-10 gallons of life in many big blocks, why NOT run 30%? (i'm not jabbing at you, its food for thought for others)

jumpanddrop

im sure many people get more then 7 gallons out of an engine