Just got my Baja 5b, how can i make this thing quieter?

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Z.hb71 said:
Anything alcohol based fuel will destroy rubber and attract moisture period. That's why we don't like ethanol.
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Yup, and I'm poking holes in your comment because me adding nitromethane has nothing to do with ethanol.
I even have pure gas!

?
 
Nitro is used with methonal, primarily to help combat the heat it produces. I'd love to see you run more then 20% and not have catastrophic failures, on these engines. Even top fuel dragsters are lucky to get more the one pass before they need tore down and rebuilt. The boys may be drinking the anti alcohol cool aid, but they arnt wrong. I'll assume you know what your doing and doing the supporting mods for it.
When the old man ran unlimited offshore, we found the difference between multiple runs, and lucky to make one was was a 2% difference. He settled on a 12% nitro mix, 15% was doable but much more engine wear. 2.3l black max mercury. Wish we had today's tech back then, I'm sure we could have pushed it a bit farther. I'll also reccomend klotz oil, as it's one of the few that can blend properly into alcohol based fuels, castor will blend as well, but would give a build up of a yellowish varnish.
Z.hb71 said:
Anything alcohol based fuel will destroy rubber and attract moisture period. That's why we don't like ethanol.
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Zed, most "rubbers" today used in fuel systems are made to withstand alcohol, they will still degrade, but it's not an over night thing. Heat will be more of an issue with straight gass with nitro, hence the alcohol.
 
Seandonato73 said:
Nitro is used with methonal, primarily to help combat the heat it produces. I'd love to see you run more then 20% and not have catastrophic failures, on these engines. Even top fuel dragsters are lucky to get more the one pass before they need tore down and rebuilt. The boys may be drinking the anti alcohol cool aid, but they arnt wrong. I'll assume you know what your doing and doing the supporting mods for it.
When the old man ran unlimited offshore, we found the difference between multiple runs, and lucky to make one was was a 2% difference. He settled on a 12% nitro mix, 15% was doable but much more engine wear. 2.3l black max mercury. Wish we had today's tech back then, I'm sure we could have pushed it a bit farther. I'll also reccomend klotz oil, as it's one of the few that can blend properly into alcohol based fuels, castor will blend as well, but would give a build up of a yellowish varnish.

Zed, most "rubbers" today used in fuel systems are made to withstand alcohol, they will still degrade, but it's not an over night thing. Heat will be more of an issue with straight gass with nitro, hence the alcohol.
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Fair enough, I don't know if that's true with the cheap rovan seals though. And even then,it still attracts moisture while sitting so purging is a good idea.
 
The most i have been able to control on a small two stroke engine is 4 -5 large cap fulls of pure nitro per 2 gallons of gas.

Most of that has been a limit of cooling, ability to add more fuel, and of course exhaust flow.

I went near 50/50 once, and much like the article, i lost control of the engine.
Destroyed the spark plug, and i ended up needing a new top end (chain saw).
 
But when it all comes down to it.
Nitro is fun.
Must tread carefully, and the biggest pita is the storage of that crap.

It's one of those things, learning will cost you some money.
But it's entertainment value is priceless.
?
 
Just Fishing said:
But when it all comes down to it.
Nitro is fun.
Must tread carefully, and the biggest pita is the storage of that crap.

It's one of those things, learning will cost you some money.
But it's entertainment value is priceless.
?
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Storage, yeah we "accidentally" dumped some of dads nitro mixed fuel into our old yz250..... ran like hell for about 5 minuets then locked the cylinder tighter then a frogs arse. Didnt do that again.
 
That's actually what gave me the idea in the first place.
Dirt biker friend of mine would use rc car fuel in his dirtbike to give him an edge in races.

I added some to a chainsaw when i needed more power to make it through the last log of a tree i wanted out of my yard.

It worked great, but permanent damage! ?

Been playing with it ever since i found 100% pure was available.
 
Seandonato73 said:
Storage, yeah we "accidentally" dumped some of dads nitro mixed fuel into our old yz250..... ran like hell for about 5 minuets then locked the cylinder tighter then a frogs arse. Didnt do that again
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Did you blow it up or did it cold sieze? Just curious, when I was young and stupid I cold seized my air cooled CR 500 when I opened it up WOT coming down a side road on a real cold fall day. Was an interesting ride that cost me a back tire and puckered my ass!
 
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Bizzer said:
Did you blow it up or did it cold sieze? Just curious, when I was young and stupid I cold seized my air cooled CR 500 when I opened it up WOT coming down a side road on a real cold fall day. Was an interesting ride that cost be a back tire and puckered my ass!
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No it melted down, we were running with a bunch of friends, ran low on fuel, not enough cash to fill all the bikes at the station, the house was just out of the way. Younger brother was getting his arse kicked pretty hard so he topped off (from reserve) with the nitro mix. Had been riding the entire day. You know back when you could have fun....
 
Well I finally decided to take this thing into my back yard, this thing sure makes my yard seem much smaller. :ROFLMAO:

Due to sun in my eyes, and using a tree to try and block that sun.
I rammed into my fire pit (sorta a 55gal drum) at full speed.
left some good sized dents in the fire pit.

All went well for a few hours of fun, then at the end of the run I noticed the front looked like it has a little more angle to it.
And tossing the rc onto the ground i heard metal to cement contact.
then I noticed it, broken!

lol
so i have the front brace on order, a new chassis, and a new top support since that's also tweaked.

I do wonder what the bad neighbor thought of it...

I also had a ton of fun blipping the throttle and using it to control turns, used my fruit trees as an obstacle course on one side of the yard, and then a nice straight away on the other side.

I don't see my grass lasting too long.


The damage! :geek:
1618260517144.webp
 
might as well make the order... saves me money in the long run i suppose. :D

Right in the middle of building up an engine for the ol boat hauler.
Weighing in how much money I'm spending on projects right now. :ROFLMAO:

1618263126148.png

ETA,
while i'm at it, the springs this thing shipped with are stupid stiff
suggestions?
also shock oil weight, and anything else related while i have everything apart?

I removed all fuel, and it's airing out...
It gets the indoors work bench since the outside one has LS engine parts on it right now. :sneaky:
 
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Z.hb71 said:
Anything alcohol based fuel will destroy rubber and attract moisture period. That's why we don't like ethanol.
Click to expand...
I started with these weed eater style motors in RC boats 25 years ago before Zens, when Homelite's engines were the thing. I've seen the idiots use alcohol and nitro. Then wonder why it stopped running. Like taking steroids. You'll look good, then one day you need heart surgery or wind up dead before your time. I have one of those small aluminum clamp on mufflers. Its does a little bit. Some places I've run in the past, next to a neighborhood, requires them to run there. Like on my old 2 stroke motocross bikes. They sound waay better without one.
'' Exhaust gas from an internal combustion engine whose fuel includes nitromethane will contain nitric acid vapour, which is corrosive, and when inhaled causes a muscular reaction making it impossible to breathe. '' I heard one Top Fuel driver say one day, with engine parts, nitromethane can turn a solid into a liquid. Goodbye engine!
 
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jbl302 said:
I started with these weed eater style motors in RC boats 25 years ago before Zens, when Homelite's engines were the thing. I've seen the idiots use alcohol and nitro. Then wonder why it stopped running. Like taking steroids. You'll look good, then one day you need heart surgery or wind up dead before your time. I have one of those small aluminum clamp on mufflers. Its does a little bit. Some places I've run in the past, next to a neighborhood, requires them to run there. Like on my old 2 stroke motocross bikes. They sound waay better without one.
'' Exhaust gas from an internal combustion engine whose fuel includes nitromethane will contain nitric acid vapour, which is corrosive, and when inhaled causes a muscular reaction making it impossible to breathe. '' I heard one Top Fuel driver say one day, with engine parts, nitromethane can turn a solid into a liquid. Goodbye engine!
Click to expand...

You can use it. In 1990 we ran straight alcohol in the G2D Zenoah engines in the 1/4 scale cars. Ran fine. One guy who was a world class professional 1/8 scale driver would use nitro also. He was ballistic but he could also drive. The problems were the carbs. Back than we were limited the the stock carb only which had plastic parts on it. By the end of the weekend he was still running the same engine but the massive amout of nitro he had killed tons of carbs. Walk by the garbage can by his pit and there was loads of them in it.
 
alcohol helps reduce combustion temps, nitro plays very well there.
with gas, I'm using less then 5%
anything more and i'm really fighting temps.

Something i learned from watching burnout comps, some guys run off of alcohol as it really reduces engine temps.
When your running WOT, high RPM, lots of load, and not really moving overheating is a thing.
alcohol = lower engine temps.
They even found you can run a smaller radiator!

It really opened my eyes to why alcohol is used with Nitromethane.

And i'm sorta hoping i fry this thing, one hand i can rebuild the engine and do some porting/cleanup while it's torn down.
Other hand, i can just spring for a better engine.


and the rc is all fixed up.
I also cracked my steering servo saver arm... :ROFLMAO:
so i just bought an entire assembly, metal one this time around...

then while installing that, i managed to break off a steering ball joint, managed to extract that from the new steering set... :poop:
and then a few more days waiting on some new tire rods with ball joints.

drilled and tapped the chassis for the front brace, so it actually threads into the chassis, then top it off with a nut on the other side.

Now to see what i break next. :cool:
 
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