help in upgrade

[pedcam1356]

hi i got stuck becouse I'm new to rc but imgoing in to this hobby to the full i bought a mta4 having a .28 engine ...

as i turned this truck all in metal alloy titanum and added a rollcage to this truck is heavy the .28 is still doing good but i would like to change and as I've been trough some researches i found 3 engines to choose from i guess these are close to best i think but i need help to choose the right one for the truck and I'm hope you can help me on this and as everyone I'm looking for the best acceleration and top speed .... so here are the models and specs

HPI Nitro Star K4.6 HO Engine w/Pull Start HPI15204

Displacement: 0.28 cu in (4.59cc)
•Bore: 18.6mm
•Stroke: 16.9mm
•Practical RPM: 3,100 - 39,500
•Maximum Horsepower: 2.95 hp @ 38,000 rpm
•Maximum RPM: 41,000
•Carburetor Bore: 9.0mm with 8.0mm and 8.5mm reducer
•
•
Associated AE 8.0 Engine: Monster MGT 8.0 ASC25480

SPECS

• Displacement: .50 cu in (8.0cc)
•Specs such as horsepower, bore and stroke were not provided by manufacturer
•I've serched some say around 15000rpm max

Axial 32RR-1
Size
.32cubic inch/5.2cc
Maximum RPM
37500 RPM
Bore
19.5 mm
Stroke
17.5 mm
Construction
ABC (Aluminum Brass Chrome)

Heat-sink Head
Axial black anodized

Carburetor
9.0mm composite slide carburetor (includes optional 8.0 & 8.5mm venturi’s)
Carburetor Adjustments
3 Needle, Flush Settings
Case
Black aluminum, rear exhaust

Connecting Rod
Dual bushing

Sleeve
6P

Starting system
Pullstarter

Recommended Glow Plug
Cold-5 power plug

 

[olds97_lss]

Personally, I'd drop the axial from the list and look at a couple other contenders.

Order of output power (from what I've gathered)
LRP28S3 - decent high revving big block that lacks a bit on the low end, but good mid/high end torque. Have ran 2 personally, one in a 1" extended savage, one in an LST and it was a good engine for both of those. Wheelied whenever in 1st gear, thirsty, held tune pretty well. Getting good life out of both. One probably has 5+ gallons through it and still runs strong, the other probably has 4 or so through it and runs great. Got rid of the lst and put the engine in a bb converted revo... total overkill, but is cool to see 2nd gear wheelies.

Picco 28 - got one in a drawer for when one of my LRP's gives up on me. More power than the LRP, bit finicky of a tune from what I've read, but a really strong engine with really long life.

LRP30 - like the 28, thirsty, but more torque overall. Haven't had one myself, but have watched many vids of this engine throwing around LST's and savage's like rag dolls.

 

[pedcam1356]

even if the items you mentioned they are lower in rpm and cc ?

 

[olds97_lss]

Yes. As the saying goes, size does not always matter...

Just like the 4.6 liter in my grand marquis puts out 215hp whereas the 4.6 liter in the mustang gt puts out 300+.

Honestly, if you spend the money, you can run a 21 that will smoke any of these engines. It's how you use what you have. Porting, timing, materials, tuning... these all make a significant difference in performance and longevity.

The HPI K4.6 HO is also a .28 and out of your list, the only one I'd consider buying. However, the others I mentioned I'd buy instead if that too.

I haven't found many that cared for the big engine in the latest MGT (8.0). Kind of like the honker in the genesis.