2.5 Horsepower for quicker starts and higher speeds
True ABC construction for long engine life and efficient power
Nitro Star S-25 instruction
manual
Click here for important S-25 engine update information!
ENGINE EXPLODED VIEW CORRECTION
In the S-25 engine manual that comes with the Savage 25, the part numbers
listed in the rear of the manual (see the far left panel below) are incorrect.
Click
the picture below to see the correct part numbers. The full exploded
view on the fold-out page (see the far right panel below) has the correct
numbers already.

Now available from HPI Racing is our
Nitro Star S-25 engine!This powerful new engine has 20% more displacement
than our Nitro Star 21BB engine!
The Nitro Star S-25 is a .25 cubic inch (4.1cc) big block
engine that features a machined billet aluminum heatsink head for extra
cooling, dual bushing aluminum connecting rod, true ABC chrome sleeve
construction for durability, and a simplified dual needle 7mm slide carburetor
for easier tuning with a composite body for better performance at higher
temperatures.

| |
21BB |
Nitro Star S-25 |
| Size |
.21 |
.25 |
| Horsepower @ RPM |
2.3hp @ 30,000 |
2.5 @ 29,000 |
| Maximum RPM |
|
38,000 |
| Heatsink Head |
cast metal |
Machined Aluminum |
| Case |
silver |
Black Heatsink Coating |
| Carburetor |
metal |
Composite |
| Carb Adjustments |
high, mid, low |
simplified to High and Low |
| Connecting Rod |
single bushing |
Dual Bushing |
| Construction |
ABC |
ABC |

Nitro Star
S-25 instruction manual
HPI Nitro
Star engines have a 2 year limited warranty. Read our Nitro
Star Engine Warranty.