Why do so many people opt for .12 engines as opposed to .15 with regards to 1/10 touring cars? Surely a .15 with a tuned pipe is more powerful & will run the car faster, right?

Because nobody makes a good .15 and they aren't legal for racing.

if your looking for more powerful 1/10 scale engine for like the parking lot, look for a .18. i know os has a good one.

So in theory I can go as high as .21 if I wanted to, as long as the engine mounted correctly on the chasis? Even though it would be well to high for cometition regs, right?

.12 is perfect for touring car though. Its smaller , lighter weight , uses less gas and revs really high.

Generally a larger motor is harder to get to rev as high is going to weigh more and use more gas. But there are some screamers out there in all sizes.

.21 you will be using a lot of gas. Youll be tearing through tires , gears and more and it will be hard to drive. But will be fast.

If you want to be smart but you want insane speed. Get the new os 18TZ the thing has 2hp = monster in a smaller package.

All your advice is appreciated, thanks guys.

after researching all day today, i noticed a lot of .12 are more powerful (hp wise) than the .15's. but companies reccomend the .15 for offroad use, and .12 fo on-road. my guess is the .15's are based on torque, such as a real truck meant for towing is.

check out novarossi.com to compare the specs on these. it's very easy to at this site, which is why i reccomended it, not because i favor them or think they have the best engines...

Actually that was going to be my next question. Have I bought a .15 engine thinking that I would get a speed increase, when in actual fact, the .15's are designed for torque & not hp?

I do see some touring cars with .15, but I presume that there angines out there that are designed for hp, not torque, just have to pick wisely I guess!

I'm gonna check out the site for further info anyway, thanks.