Ive got several offroad machines and 1 NTC3 on the way. My question is, what is the difference between an engine made for onroad and one made for offroad? I see an awesome 1.8HP engine Id like to buy however it says its for offraod. To me, they look the same. Maybe RPMs? Power Curve?

Any ideas?

PS - I think Im getting the Sirio .12 Outlaw... Would that be about the fastest engine for it?

offroad you want more torque down low but hence not as much rpm also acompanies this, where as onroad you want more rpm/hp=speed hence torque down low is less required (no doubt still wanted) its where priorities lay.

like in real vehicles

on most onroad tracks you rarely get full speed though so still torque is pretty high in the priorities.

link the engine here so we can check it out.

im certainly no expert (or even close, or even good) and i tend to agree with u, hence there is no great difference between on and offroad rc engines ie most are used for either (unless i'm nieve) compared to say real car engines.

its when you compare say a diesel (ie offroad) with and nitro onroad that u see a difference

http://www2.towerhobbies.com/cgi-bin...?&I=LXCKX9&P=0
This is the Sirio .12 Outlaw.

http://www2.towerhobbies.com/cgi-bin...?&I=LXDRC0&P=0
This is the Sirio .15 AF with 1.7 (Not 1.8 as I mentioned earlier)

According to their website - http://www.teamtrinity.com/nitro/eng...irio/sirio.asp - the .12 has 1.45hp 40,000RPM and the .15 has 1.7 39,500RPM. The .15 is also a little cheaper but that doesnt matter much.

Anyone see anything wrong with putting that .15 AF into the Nitro TC3?

if you are going to race go with the .12 since it is better on fuel, and weighs less... plus i think to be ROAR legal, it has to be a .12... but if you are just playing aroud and stuff.. get the .15.

the higher the RPMS the faster the turn and the faster your car will go, that's great for onroads, and for offroads, you want torque most of them, however I like fast power so I'm taking a onroad 21 and putting it into a offroad

Since the .15 has more HP, wont that allow me to run a lower gear ratio to produce more speed than the .12?

Given the same ratio, the .15 should get up to speed faster than the .12, right? That should mean that I could lower the gear ratio a little more with the .15 which would make the car faster but still allow it to keep the acceleration.


Right?

--Does anyone have any other suggestions for the engine on this car? Im not going to race with it - I just want it to be fast.

I'd go w/ the .15 and if you want more top end you want "taller', or lower numerically (higher) gears. Theoretically, yeah, an engine w/ more torque, but same R.P.M. capability should provide quicker accelleration, if you have adequate traction, w/ the same gears. If you have a wheelspin problem, taller gears will help cut that down, because the engine won't be as close to peak torque R.P.M. until the car gets going faster. If you also want it to handle, the .15 is prob. the best choice, because a .21 makes for a top-heavy 1/10 scale, and you'll find that tire selection becomes more critical. The Fusion just blows the tires off w/ the slightest touch, and does donuts in the blink of an eye Actually, it's pretty cool, but gets to be a P.I.A. buying tires, (you have to get the belted radials, so they don't fly off the rims as easily) and sometimes, like now when it's colder, it's really hard to get it to hook-up. And, the colder air means more power, which exacerbates the problem...Sure does sound nice tho, just like a hi-po dirt bike, when it's shiftin', and on the over-run....Over-all, I'd say it was worth it, 'cuz when the adrenalin's flowin', and she's singin' at top speed, it's wicked cool[8D] Just don't hit your foot! Friend of mine did, w/ his LD3, and went to the emergency room, and when we told 'em "He got hit by a car", none of them would believe us, 'till we said an R/C car