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-   -   dynamite big red engine in LST. under powered? (https://www.rcuniverse.com/forum/losi-monster-trucks-319/11637734-dynamite-big-red-engine-lst-under-powered.html)

RCaddict80 03-28-2017 04:50 AM

dynamite big red engine in LST. under powered?
 
hey guys..i just recently purchased a "like new" losi LST with the mach .26 engine.this thing is practicly brand new, still in the box with all origional paper work..ect.. however its been sitting for the past 8 years so the engine was gummed up super bad so i just decided to get a new engine for it..i already have a new LRP Zr32 in my savage only on 5 tanks and im telling ya that engine is way too much power! so i decided to go with a .28. so i purchased the dynamite big red engine which is rated at 3.4horse power. i havnt began the break in process yet because im waiting for decent outside temps..however now im worried that this truck is not going to perform very well and is going to be underpowered. i shouldve went with the losi 454 or LRp28. does any one know if the big red engine is powerful enough to make it pull wheelies? will it move the truck around pretty good? or will it be struggling to perform? the factory engine is rated at 2.75hp so it has to be better than factory engine huh? thanks guys

1QwkSport2.5r 03-28-2017 05:21 AM


Originally Posted by RCaddict80 (Post 12320882)
hey guys..i just recently purchased a "like new" losi LST with the mach .26 engine.this thing is practicly brand new, still in the box with all origional paper work..ect.. however its been sitting for the past 8 years so the engine was gummed up super bad so i just decided to get a new engine for it..i already have a new LRP Zr32 in my savage only on 5 tanks and im telling ya that engine is way too much power! so i decided to go with a .28. so i purchased the dynamite big red engine which is rated at 3.4horse power. i havnt began the break in process yet because im waiting for decent outside temps..however now im worried that this truck is not going to perform very well and is going to be underpowered. i shouldve went with the losi 454 or LRp28. does any one know if the big red engine is powerful enough to make it pull wheelies? will it move the truck around pretty good? or will it be struggling to perform? the factory engine is rated at 2.75hp so it has to be better than factory engine huh? thanks guys

Forget about factory horsepower numbers. They're meaningless. That Big Red .28 will likely not pull more than 1.5-1.8hp on a dyno. That isn't to say it won't do wheelies. If your truck has the stock transmission, it will wheelie. Easily. You can save some weight if you convert the transmission to Forward Only. It will wheelie easier to the point of almost uncontrollable. I had a 6-port SH .28 (same engine as LRP Spec 2 .28) in one of my LST2s and it was a wheelie monster. I did the gear flip mod to take the wheelies down some and add some top speed to it. Much happier that way.

The Big Red is basically the same engine as the LRP .28 Spec 3 and Losi 454; literally. Made in the same factory. If you want to get some good top end out of it, put a Novarossi 9886 tuned pipe and Novarossi 41017 manifold/header on it. The Losi HT pipe (stock pipe on LST2 and XXL trucks) is very similar to an 053 low-mid pipe and is great for gobs of low end torque but absolutely kills horsepower and top end speed.

FWIW - those stock LRP .32s are about as powerful as a good .28 like the Novarossi Legend 28-8 ($180 engine).

McFlyz 03-28-2017 04:29 PM

I was going to say the same thing about those numbers. 3.5 hp is a ton of power and the dynamite big red with a upgraded carb & head was rated at 1.9hp. Not sure how they got those numbers. Regardless of the numbers that engine was a good strong puller in my friends 1/8 scale Buggy so you should be fine in a lst 2. Keep us posted on how it works for you.

1QwkSport2.5r 03-28-2017 05:06 PM

FWIW - a good strong modified .28 will pull right around 3hp on the dyno. Bone stock, probably just a hair over 2hp.

McFlyz 03-28-2017 06:06 PM

I have never seen a .28 pull even near that HP. Never listen to numbers given by the company. Cars, motorcycles, rc engines and so on, they give you a certain hp number then you dyno it and not the same, not even close. This list is from this site with hp numbers on a dyno. Hope this helps.

I never pay too much attention to HP numbers but for those who really cares... It's a bit old but a good reference


Issue # Company Engine Size (ci) Ave. HP Ave. TQ Low (HP/TQ) Top (HP/TQ) Corr. Factor Peak HP Peak Torque Peak RPM Price
111 O.S. 12 TR 0.120 - - - - - 0.65 @ 30,000 rpm 25.00 oz-in @ 23,250 rpm 39,350 rpm $130
111 Trinity 427 Monster HP 0.260 - - - - - 1.02 @ 24,250 rpm 48.00 oz-in @ 19,250 rpm 38,100 rpm -
112 Mugen Seiki X12 SE 0.120 - - - - - 0.88 @ 21,500 rpm 28.80 oz-in @ 30,000 rpm 42,500 rpm $290
112 O.S. 12 TR-T Outlaw 0.120 - - - - - 0.73 @ 31,500 rpm 25.96 oz-in @ 27,250 rpm 41,000 rpm $160
112 O.S. VZ-B V-Spec 0.210 - - - - - 1.47 @ 24,250 rpm 61.20 oz-in @ 22,500 rpm 41,500 rpm $320
112 RB Concept V12 Rody 3T 0.120 - - - - - 0.95 @ 34,250 rpm 28.80 oz-in @ 28,750 rpm 44,750 rpm $375
112 Rex R12S5 Outlaw 0.120 - - - - - 0.84 @ 34,750 rpm 26.88 oz-in @ 26,750 rpm 41,250 rpm $385
112 Rex ReR5 5-port turbo 0.120 - - - - - 0.84 @ 34,750 rpm 27.00 oz-in @ 26,750 rpm 41,250 rpm $320

1QwkSport2.5r 03-28-2017 06:57 PM

Neal at the Nitro shop just did a dyno test of a modified Picco or Nova .28 on some different manifolds and pipes. Turns out a short conical manifold and 9886 pipe on an already stout modified .28 pulls over 3hp. Bone stock was somewhere in the 1.9-2.1hp range. So no, this wasn't the company saying it. If a modified engine is pulling close to 3hp, you know damn good and well a stock "budget" engine sure as heck isn't pulling close to 3hp.

RCaddict80 03-29-2017 05:06 AM

thank you for your replies and comments.i got alot of good info out of you folks!! yeah i always knew thoes figures are rubbish.and as far as the decision i made on the engine purchase....i now own three 1/8th scale nitro monster trucks. and 6 nitros all together. i own like 20 rc trucks all together. in the last year i have bought a new os18crvx for my rc10gt2, lrp32 for my savage, and now the big red for my lst. i might have to replace the engine in my t maxx this summer. but my point is...i pick these trucks up for next to nothing and i totally rebuild them and put new engines in them. i cant exactly afford to put $250-300 italian engines in my rc trucks!!if i only owned 1 then have the best modded engine avalible. but since i have multiple nitro mts that also means im not using the same one over and over again. so the $200 LRP32 and the $140 dynamite and the $100 OS 18 engines are about where my budget lies.

RCaddict80 03-29-2017 05:10 AM

so what you guys are telling me is that dynamite big red engine will be plenty of power for the stock LST? it will have the power to move it self out of the way and maybe do a few wheelies? only experience i have with big blocks is the MGT 8.0, HPI4.6, and LRP32. and out of all thoes the LRP32 is way stronger than any of them.even the 8.0 is not as strong in stock form IMHO.well i hope i made the correct decision with the big red. if not,,i supose i could always swap the big red out for the LRP32 LOL

1QwkSport2.5r 03-29-2017 06:03 AM

The Big Red will push an LST around fine. And in regard to your comment on a $250-300 engine - the Novarossi Legend 28-8 is $180 shipped if you get it from Novarossidirect.com. I was a devout SH/Mach/LRP/XTM engine fan for a lot of years... After I bit the bullet and bought some Picco and Novarossi engines and really compared the minute details between them and the SH/Mach engines did I find how much better the Italian engines are. Novarossi is cheaper than Picco these days, but are every bit as powerful and more than the cheapies. Do a search on YouTube for Novarossi legend LST and you'll see some videos of the bigger XXL getting pushed around by one of these nicer engines.

In the end, the Big Red will do the job though. When you're ready for an engine that tunes easier and runs stronger than the Big Red, try a Novarossi. They've never been more affordable - they're cheaper than the LRP!

geepfreek 03-29-2017 07:18 AM

I had a LST back in the day and the Mach 26 and when it was tuned right it would scoot! I was never into just doing a bunch of wheelies so my low end was richer than others set theirs. Will it do it? Yes. Is it a strong enough motor to move this big truck?Yes. As well as you want it? That's your perception. I enjoyed the heck out of mine.

RCaddict80 03-30-2017 05:04 AM

thank you for your relpy, i dont exactly like to pull wheelies all the time. in my opinion if aan engine is strong enough to make a truck pull wheelies then you know its planty powerfull enough for that specific truck and its not going to put alot of stress on that engine while running it in that specific truck. yes i had no idea the rossi engines was that cheaply priced.i have no experience with them.only sh, o.s, HPI, TT, thoes types of engines. i do have another savage roller laying around that needs front and rear diffs.maybe ill put the big red in that and buy a rossi engine for LST

1QwkSport2.5r 03-30-2017 06:21 AM

3 Attachment(s)
The Nova is a sweet engine. I will be breaking mine in this weekend possibly.
Some videos I pulled from YouTube -
Big Red LST2: https://youtu.be/Cno3CVUL-ic
LRP .28: https://youtu.be/eMS0yWJJuAk

Novarossi Legend 28-8 in an LST XXL: https://youtu.be/SH9TMB4tNIo (note the engine exhaust note compared to the other videos. You can tune the Rossi much sharper than you can any of the SH variants. This is one of those minute details you can't read about or see with the naked eye. The Rossi does use turbo glow plugs which are a little more expensive than standard plugs, but they take more abuse, last longer, and make more power.

Another from the same guy. https://youtu.be/Ihuc7OX6kdQ

Pictures below of my pair of LST2 trucks. Nova Rex Legend 28-8RT in one and Picco P3 .28 in the other. The Picco P3 is discontinued; replaced by the Picco Boost line. I got the P3 NOS from my LHS for $184 which is a steal. I found a NOS piston/liner for $50 too, so I have backup parts for it. After experiencing these engines, I'll never buy another SH based engine. I guess I'm an engine snob now. ;)

RCaddict80 03-31-2017 07:25 AM

very nice engines...looks like you got your fuel lines attatched wrong

1QwkSport2.5r 03-31-2017 08:27 AM


Originally Posted by RCaddict80 (Post 12321910)
very nice engines...looks like you got your fuel lines attatched wrong


I disconnect the fuel line from the carb and connect it to the pressure fitting on the tank when not in use so fuel doesn't stay/get in(to) the engine. I run the engines absolutely dry at the end of the day. I also set the piston to BDC so the ports are open and allow the crankcase to air out so to speak. Any residual fuel residue inside the crankcase will eventually cause rust to happen.

McFlyz 03-31-2017 08:39 AM

After run oil (marvel mystery oil) 3-5 drops in your engine it will never pit or rust I have a 27 year old nitro motor that still runs due to that oil.

1QwkSport2.5r 03-31-2017 09:21 AM


Originally Posted by McFlyz (Post 12321933)
After run oil (marvel mystery oil) 3-5 drops in your engine it will never pit or rust I have a 27 year old nitro motor that still runs due to that oil.


If there is any fuel residue inside, covering it with oil seals it in and can make it worse. If you use a fuel with a good dose of castor in it, you probably won't deal with much rust. Fuel with mostly or all synthetic oil will wreak havoc on the steel parts.

RCaddict80 03-31-2017 12:52 PM

AAAH, i definatly always put engine BDC, but never thought about close looping the fuel system. great idea man

1QwkSport2.5r 03-31-2017 02:31 PM

If the tank is near empty and the fuel line is clear of any fuel, it likely won't feed into the engine, but I don't take any chances.

McFlyz 03-31-2017 03:16 PM


Originally Posted by 1QwkSport2.5r (Post 12321942)
If there is any fuel residue inside, covering it with oil seals it in and can make it worse. If you use a fuel with a good dose of castor in it, you probably won't deal with much rust. Fuel with mostly or all synthetic oil will wreak havoc on the steel parts.

Since when does synthetic oil cause issues with metal like rust. I have used it in every dirt, street bike, RC car and personal vehicle and never had a issue from synthetic oil. Just the opposite, it's causes very little wear on metal to metal parts. Protects metal and will not break down like a conventional oil will under heat and stress loads. I have never had and internal engine piece rust from synthetic oil.

1QwkSport2.5r 03-31-2017 03:48 PM


Originally Posted by McFlyz (Post 12322031)
Since when does synthetic oil cause issues with metal like rust. I have used it in every dirt, street bike, RC car and personal vehicle and never had a issue from synthetic oil. Just the opposite, it's causes very little wear on metal to metal parts. Protects metal and will not break down like a conventional oil will under heat and stress loads. I have never had and internal engine piece rust from synthetic oil.


Model engine synthetic oils are very different than the synthetic oils used in gasoline engines. The chemistry is very different. It is a well known fact that a full synthetic model engine fuel will not protect a nodel engine nearly as well as a castor/synthetic blend will. Your safety margin is much narrower on a full synthetic lube in model engines. The PAG synthetic oils used in model engine fuel were never designed to be used in internal combustion applications. It was originally designed for sealed refrigeration systems. Exposed to moisture and acidic combustion byproducts makes a nasty cocktail of crud that can wreak havoc on model engines.

McFlyz 03-31-2017 05:23 PM


Originally Posted by 1QwkSport2.5r (Post 12322035)
Model engine synthetic oils are very different than the synthetic oils used in gasoline engines. The chemistry is very different. It is a well known fact that a full synthetic model engine fuel will not protect a nodel engine nearly as well as a castor/synthetic blend will. Your safety margin is much narrower on a full synthetic lube in model engines. The PAG synthetic oils used in model engine fuel were never designed to be used in internal combustion applications. It was originally designed for sealed refrigeration systems. Exposed to moisture and acidic combustion byproducts makes a nasty cocktail of crud that can wreak havoc on model engines.

that's is just crazy and every thing i have ever read said to stay away from castor oil, it's the main issue. it's the nitromethane and alcohol that destroys metal. maybe back in the 50's the oil blend may gum up easy but the new synthetic oils do not do this at all. This is off another site and i just copied it, i have always done in this way and never had a engine gum or seize on me.

The oil content recommended by Saito and Horizon Hobby is 20%. Horizon Hobby state that oil that is a blend of castor and synthetic is acceptable. Saito instructions (that no longer accompanies engines sold in the US) say the following: “Since the four-stroke engine has high exhaust temperature and carbon is apt to accumulate when castor oil type lubricants are used, avoid using fuel containing them.” This seems to imply Saito recommends fuel with no castor at all.

It is not clear that 20% total oil content is really needed as 15-18% seems to work fine and is common with commercial fuels labeled for 4-stroke engines. It is really also unclear that all-synthetic, or a blend of castor-synthetic, is preferred; both are probably OK, however no more than 5% castor with the remainder synthetic oil is usually recommended. Byron 4-stroke fuel has a total oil content of 16% with about 3% castor and the remainder synthetic.

I have heard from some European Saito flyers who are mixing their own fuel with 10% total oil content. No adverse effects have been reported. However 15% to 20 % is a safer blend.

In summary, any commercial 2-stroke or 4-stroke fuel should be fine, provided you make sure the castor oil content is low, with mostly synthetic oil. The only difference between commercial 2-stroke fuels and 4-stroke fuels is the total oil content (4-stroke fuels typically have 2-3 % less total oil content compared to 2-stroke fuels).

1QwkSport2.5r 03-31-2017 10:56 PM


Originally Posted by McFlyz (Post 12322050)
that's is just crazy and every thing i have ever read said to stay away from castor oil, it's the main issue. it's the nitromethane and alcohol that destroys metal. maybe back in the 50's the oil blend may gum up easy but the new synthetic oils do not do this at all. This is off another site and i just copied it, i have always done in this way and never had a engine gum or seize on me.

The oil content recommended by Saito and Horizon Hobby is 20%. Horizon Hobby state that oil that is a blend of castor and synthetic is acceptable. Saito instructions (that no longer accompanies engines sold in the US) say the following: “Since the four-stroke engine has high exhaust temperature and carbon is apt to accumulate when castor oil type lubricants are used, avoid using fuel containing them.” This seems to imply Saito recommends fuel with no castor at all.

It is not clear that 20% total oil content is really needed as 15-18% seems to work fine and is common with commercial fuels labeled for 4-stroke engines. It is really also unclear that all-synthetic, or a blend of castor-synthetic, is preferred; both are probably OK, however no more than 5% castor with the remainder synthetic oil is usually recommended. Byron 4-stroke fuel has a total oil content of 16% with about 3% castor and the remainder synthetic.

I have heard from some European Saito flyers who are mixing their own fuel with 10% total oil content. No adverse effects have been reported. However 15% to 20 % is a safer blend.

In summary, any commercial 2-stroke or 4-stroke fuel should be fine, provided you make sure the castor oil content is low, with mostly synthetic oil. The only difference between commercial 2-stroke fuels and 4-stroke fuels is the total oil content (4-stroke fuels typically have 2-3 % less total oil content compared to 2-stroke fuels).


And the fuel needs for a ringed four stroke airplane engine are completely different from the fuel needs are for a tight ringless ABC/AAC car engine with a tight pinch and no forced cooling. Castor will varnish with heat. A little bit is okay, a lot can slow the engine down. A little synthetic oil in the mix keeps this at bay. Castor oil will dry out over time and gum the engine up - takes 4-6mos to do this. After run oil prevents it, however that layer of dried castor oil will protect the metal better than nearly anything else. Synthetic oil doesn't dry out like castor does, but it does absorb moisture.

In the 20yrs being in this hobby, I've found the commercial fuels to not be up to snuff. Since I started mixing my own fuel, I've found a good balance between long term storage gumming (none) and good running characteristics. Most commercial fuels only have 1-2% castor and balance synthetic. I've found that a car fuel with a total oil content of 10-12% of which 6-7% is castor, my engines run cooler, faster, longer, and don't gum up. Another point many guys fail to notice is that leaning the engine to oblivion to get the last little bit of power from it will push the commercial fuel beyond its limit in regard to protection. One must understand the limitations of the fuel, but if the manufacturer doesn't publish what they put in the fuel, the average operator is in the dark. Last point I will make is this: The cheap engine manufacturers don't specify what kind of fuel mixture to use - the good engines will have instruction as to what fuel mixture (composition) is best. Picco specs all castor oil at 10% content for running and 12-14% for breaking in. Novarossi specifies to add 5%, then 3%, then 2% oil (50/50 castor/synthetic blend) to the standard fuel for breaking in (15% total content for first liter, 13% second liter, and 12% third liter) with the final composition being 4% castor and 6% synthetic for a total of 10% oil. Novarossi specifies to use their 1n1 oil for after run oil which is pure castor oil.

Enough about fuels and oils - the thread is getting way off topic. If what you use works for you and gives your engines 7-8+ gallons of use, use it. If not, switch it up and use something better.

RCaddict80 04-06-2017 11:58 AM

just a quick update guys..i got a chance to start the break in process on my LST with big red engine. started right up 2 pulls..but had to lean it out just to get it to move.lol factory settings are set so rich it dies as soon as you apply a little throttle. but all my worries are gone. i got 5 tanks through it and its plenty of power.even though its still running rich and about 190-200 degrees it will pull wheelies! it seems to be geared alot lower than my savage. i been looking at tring to gear it a little higher.but all is good

RCaddict80 04-10-2017 04:33 AM

hey guys another update on LST and in need of advice. i ran my LST over the weekend put a few more tanks through it..also switched fuels from blue thunder sport 20% to speedblend 20% oddonell. i run oddonell speedblend in my savage with LRP ZR32 and love it so i did the initial engine run in for big red with bluethunder than switched. it runs super awsome. great temps about 220 and end of tank about 240. this thing has loads of bottom end but it dosnt really rev out as nice as my lrp32. done my research and folks are talking about how the header pipe on LST is too long and thats why it dosnt have any top end. does anyone have any suggestions on how to improve my mid to top end power and speed?i understand its always a trade off and im willing to trade some of this bottom end.it has the bottom end to pull tree stumps! and wheelie on demand. i dont really want to start messing with the gearing just yet. integy makes a pipe special for the LST called the "high powered tuned pipe for LST/LST2/XXL" part number T7346. maybe that would do the trick? header pipe looks the same leingth in pics but may be bigger in diameter. any thoughts and suggestions are welcomed thanks

1QwkSport2.5r 04-10-2017 07:07 AM

The Losi HT pipe and LST header are good for gobs of bottom end punch, but are lackluster at best for top end. The HT pipe is similar to an 053 type of pipe - favors bottom end. Switch to a shorter header and better pipe. I run a mod Picco .28 (timed fairly high) with a Nova 41016 conical manifold and Dynamite 086HS pipe. The higher timing needs a shorter manifold (exhaust system overall, really). My other truck has a Novarossi Legend 28-8 timed a little lower; I use a Novarossi conical 41017 header and Novarossi 9886SS pipe which works unbelievably well. My suggestion: get a Novarossi conical manifold #41017 and Nova 9886 pipe. You will see the engine completely differently.

The manifold has more bearing on engine behavior and performance than the pipe itself does most often. The Big Red should have enough timing to make good use of the shorter manifold. Any pipes or pipe and header combos marketed for the LST trucks will favor the bottom end of the rpm range. I guarantee you the Nova manifold and pipe set will make you grin from ear to ear. I sure do! At the very least, try a different header. I'd run a GPS on it before a manifold and/or pipe swap, retune the engine (set it richer to start with - it's gonna need it), and re-test the top speed.


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