Will a CEN 7.7 fit on losi lst
 

Have a losi lst with a .26 and looking to make this thing fly i was thinking i would like to put a CEN 7.7 engine onthere will this work and just drop in or any one have any ideas on a great motor to put on this truck 4.0 horsepower or more

RE: Will a CEN 7.7 fit on losi lst
 

Forget about horsepower numbers. They truly are meaningless if they're coming from the manufacturer. On the Cen engine... Just because its bigger doesnt mean its better. I think your best bet on any Losi Monster truck is a stout .28, FOC conversion with gear flip mod, Reverse delete, and some really good steering servos. This would make a rock solid, fast, wheelie giving monster truck. I personally havent ran a 7.7, but I would imagine its not much of a revver. A .28 will outrev that 7.7 by a far more usable margin. I personally dont see an LST benefiting from any engine larger than .30ci displacement. Real world power numbers for that .26 its got now is probably in the 1.2-1.6hp range. A good, high end .28 will see 2hp or a tad better.. maybe 2.5hp?

What exactly do you want the truck to do? Wheelies all day long or be fast and give up the wheelies on command?

RE: Will a CEN 7.7 fit on losi lst
 

ok thanks im looking for it to go fast no wheelies what about the hpi 5.9 .36

RE: Will a CEN 7.7 fit on losi lst
 

Stay away for the 5.9 its a crappy engine.

Lrp .28 and .30(2)? are great engines, the picco .28 is another good engine but more for the advance user. I can't believe I'm about to say this but if your just looking for speed then a brushless conversion would be in your future.

RE: Will a CEN 7.7 fit on losi lst
 

Gearing also helps. If anything thats the first thing you'll want to change out before trying a new engine

RE: Will a CEN 7.7 fit on losi lst
 

Trying to make an LST go fast is going to take more than just regearing it. These things are pigs and it takes a copious amount of power to get them moving fast. A good engine is a must, swapping out for the tallest clutch and spur combo available, and then using the transmission gears from the Brushless conversion kit to be stupid fast (for an MT) and FOC kit.

This would be the way I'd go if I wanted to build an LST for speed. The Mach .26 will get it moving decent, but if top speed is the objective (and it is) then that engine wont cut the mustard. A very good .28 or .30 will be needed.

RE: Will a CEN 7.7 fit on losi lst
 

Depending on what .28+ BB engine you get. The bigger the cc the less top-end they tend to have (unless you have a $200+ high end engine). To compensate for the bottom end torque you get with a bigger cc engine you change the gearing. (kinda why you might put a higher tooth clutch bell on a buggy with a .28 engine)

Example: Axial .28 Spec 1 is a bottom end engine with little to nothing for top end. Mach 26.SS however has greater top end but wouldn't get anywhere off the line over a .28

Axial .28 Spc1 Bottom end
Mach .26SS Mid-Top
Mach 427 Bottom-Mid and still has more top end then the .28 Spc1
Point being, bigger doesn't always mean faster and just because you slap in a .30 doesn't mean squat. If your gearing is stock a bigger engine will get you to your gearings top end a little faster.

Yes im aware of what kind of energy is needed to move a LST (still have pictures of my .28 Axial then Mach 427 then Picco .28 Aftershock on my profile)

LRP z.28 is one of the engine most people buy when they want "real" power without spending over $200. Not sure if losi's 454 and the z28 are the same engine inside[:-]

An electric conversion kit + single speed gearing + Forward Only Conversion + ESC&Motor& the Batteries to power it = well into $400-$500 range (more then a high end engine)

RE: Will a CEN 7.7 fit on losi lst
 

First off, displacement has nothing to do with if the engine makes more top end power or bottom end power. The biggest factors that influence the powerband are the number of ports, the size of the ports, the timing of the ports, the size and shape of the crank port, the size of the crank induction channel, the compression ratio, and on and on and on. Whats more, the exhaust has a big influence on where the power is generated also. You can have two identical .28 engines side by side with two completely different exhaust systems and see a major difference in how they perform. The trapped compression ratio along with exhaust timing would be a dead giveaway as to where the engine will make its best power. Even more; You could put a 3-port engine with larger ports and better timing against a 6 port engine with more smaller ports and the 3-port could very well outperform the 6 port engine. Generally, more ports means more top end but that isnt always the case. The M26SS engine uses a high compression head button (same head button the Teal Mach 427 uses) and 3 port sleeve. I dont know the port timings for that engine off hand, but the one I had was far better down low then any of my Mach 427 engines using the same fuel and exhaust. My teal 427 was stolen before I could ever get it broke in and really opened up, sadly.

The LRP .28 spec 3 and the 454 have the same bore, stroke, carburetor, number of ports... but again, I dont have either to check the port timing to know if they're timed the same or not. They're made by the same factory, so its very possible the only differences are cosmetic.

As far as electric conversion - I never said anything about converting to electric. The Losi Brushless conversion kit has different transmission gears with (IIRC) more teeth than the stock LST/LST2/AFT transmission gears. The XXL has 1 tooth more than the stock LST/LST2/AFT, and the BL gears have 1 more tooth than the XXL gears. If you have an engine that makes enough high end torque, an LST with the BL gears (and if there's room, do the gear flip mod), Max spur/clutch ratio, and low profile road tires, you would have a faster LST than if you had a stock .26 geared to the max only. Yes, you might get more speed just by regearing... BUT to get more speed, you need to add more power, and more gears to take advantage of the power. In order to add more power, one almost always needs to add displacement.

The problem with RTR engines is they are not timed as well as the high end race engines. They will not turn the rpm a good high-end engine will. What I meant by a good engine is one that is timed and ported to make top end power, and lots of it.

I'm not questioning your logic, but I will say speed costs money and a RTR sport engine is not going to produce the gusto needed to go that much faster even with the best gearing possible. They just run out of steam. IMO, all of the engines you listed among many others, are just that. Sport engines. They are sub-$200 engines that anyone can break-in and run and get decent performance from. They are not anything close to a Novarossi, Picco, JL, etc. in top end performance.

RE: Will a CEN 7.7 fit on losi lst
 

Not 100% if the .26ss and teal 427 came with a HC head button (it was a aftermarket add on). Unless Losi/Dynamite started selling the M26 engines with the HC head. The teal 427 had a slightly bigger & "better" carb then the orange 427, which was why they sold those in the muggy and not the lst's. When I had my 26ss I can guarantee it didnt come with a HC head
2nd timing. Each engine has its own timing and we know this, but show me a few .28 or bigger that has a high USABLE RPM band under $200. A .12 is more known to reach into the higher RPMs over a .28+ but it still is a .12 Small block. Yes a .28 can hit 38,000 but odds are its going to be a "purpose built" engine (race engine). Most RTR engines don't use advanced timing or modified ports for that matter
Yes cc does have something to do with it, so does timing and the exhaust ( LST's have HT pipes and those are great pipes), GEARING (clutch, tranny and final drive), tire size etc.

K.I.S.S.[&:]

We're not talking about the logistics of each engine to engine, Im talking from Personal experience.my .26ss had less ports then my .28 and the .26ss had way more top end(but that was just my two engines not a $400 Nova Rossi). The cheapest way to get more "speed" is to change the gearing and maybe wheels&tires. If you have the extra $$ for a new engine killer.

RE: Will a CEN 7.7 fit on losi lst
 

the 454 and z28r are the same internally(sleeve, piston, head button) but have a different carb.
the z28r carb is insulated, where the 454 is not. some have reported ''boilling fuel'' problems with the 454 but i did not with the 2 i owned.

RE: Will a CEN 7.7 fit on losi lst
 

Head button for M26SS and Teal Mach 427: http://www.horizonhobby.com/Products...ickAccessories
Head button for Mach .26 and Orange Mach 427: http://www.horizonhobby.com/Products...ickAccessories
Here's a thread that talks about the two different 427's and their differences. http://www.rcuniverse.com/forum/m_72...mpage_2/tm.htm
There isnt much info out there about the M26SS. I never measured the carb on my M26SS, but It really was a more stout engine than my orange 427.

As far as the budget .28's that have a high usable powerband... That takes experimentation with pipes and fuels to get decent power, but usually the timing of the ports needs to be modified to get that kind of power and rpm from a RTR sport engine. What I meant by a good .28 engine is spending $300+. That is if someone really wants to go fast.

Comparing big block rpm to small block rpm is apples to oranges. I'm well aware some .12's and .15's will get into some crazy rpms but without there being a good tachometer to test car engine rpms, its all heresay and speculation. I'll agree to disagree with you, and thats cool..

RE: Will a CEN 7.7 fit on losi lst
 

LRP Spec 3/Losi 454, and XXL gearing, with stock LST2 wheels and tires makes for a very fast MT.. Cheap and simple. Faster than most MT's really need to be going on pavement.. Fun though.. :)

RE: Will a CEN 7.7 fit on losi lst
 

yeah with the xxl tires(like running on gravel!) i have+19/26 endbell it moves out with a .25.have not topped it out yet..............

RE: Will a CEN 7.7 fit on losi lst
 

That Losi 454 is a sweet priced motor!
and I did not know they were the same
I have a Truggy and Muggy with the Mach 427 and put a JP-4 pipe on my Truggy and wow!
the throttle just snaps on my Truggy now..
cool info on this thread about motors and timing
anyone have a suggestion about doing some porting or polishing on a stock Mach 427 vs. the power of having a LRP or 454 motor?

thanks! ;)