Whats The Diffrence.

[Joehpi1]

Whats the diffrence between a engine size 12,15,18 and which is better for what. I have a 18 on my RS4 3 and some one had told me that a 12 would be better. So I'm confuse.

 

[Mr T-Maxx]

The numbers refer to the size of the engine. More often than not measured in cubic inches.

therefore....

.12 = .12 cubic inches of displacement
.15 = .15....etc....etc.

As to what is best...that is a personal preference.

hope this helps,

Mr T

 

[Revo Rancher]

If you have the 18 SS stick with that unless you plan to do ROAR racing. In nitro touring car most ROAR races require a .12 motor unless they have an outlaw class. That .18 that comes with the SS is a pretty powerful motor, more than enough to get you started and placing in TC races.

 

[Candyman]

Let me start by saying there are many many "rules" in this area. But let's go with the basics. The number (.12, .18, .15) is the engine displacement in cubic inches. So, the higher the number, the more displacement. Typically, more displacement equals more power. Typically. But that is not always true. There are tons of other factors like crank design, porting, carburetor etc. As far as which is better for what, well that depends on the car and where it's running. Many high-end competition level .12 engines will actually run a touring car faster and quicker than a middle grade .18. It all depends on how it's built.

 

[Pinblaster]

One thing you have to realize is that most RTR's come with those big engines (.15 and .18's) to get your attention in the sale adds. They tell you they are ready to race at the track and will get you first place in no time. However they fail to inform you that those motors are not legal to race in 10th scale ROAR and IFMAR races. Some clubs will let you run them in RTR's until you start winning races and ppl start complaining, then they will pull out the rules and tell you to put a legal .12 in it. Also most of the RTR's come with low end .15's &.18's (usually P/S) poor quality factory rejects that the RTR builders use to keep cost down. Same with the electronics on most RTR's. If you take the time to compair the spec's on the RTR 15/18's with the spec's on the OEM engines of the same size, you will see a big difference in HP. Also you have to consider power to weight ratio. While the bigger engine might have a tad more HP it also has a tad more weight that it has to push. Next you have to think about getting that extra power to the ground. If you run an off road stadium truck on a dirt track with loose dirt, getting power to the gound isn't so easy. So you end up being slower with a bigger motor that spins out at every turn, than the guys running smaller engines that don't over power their rig and passes you every time you spin out.

 

[Diver6127]

Also remember, the torque from these bigger engines will get the car out of line due to the centrifical forces from the flywheel as well as the crank. The car will ahve to be setup to compensate for this. .12's are typically mid-high performers with snappy holeshots (provided the clutch engagement is setup correctly). Also, CG is affected from the bigger cooling heads so lateral stability is compromised.

In a nut shell, the .12's are the true racers. .15's are still roar legal, but in a different class. .18's are strictly outlaw. For both .12 and .15's, there is a 3 port limit. Over that and you're running outlaw.

Remember, bigger is not necessarily better. Case in point, my schumacher Fusion21 had a BB .21 engine in it with a 3 speed. It was rated to hit over 70+mph,and it did on a regular basis. When compared to my brothers NTC3 with an RB V12 3port (.12) side by side in a drag and on a laid out track, I was out handled as well as beat every single time in the holeshot. Given enough room and I would win, but in a real race situation, that was never the case.

 

[Revo Rancher]

Wow, Diver, that was an interesting story. Guess I will stick with .12's for my TC.

 

[sl0eg1n]

while setting up your car for a race you always want your car to be fast in the infield as opposed to the long straight.