Ok ill step into the ring. I run on a small tight track and have raced against all the motors you have been talking about except the WASP. I dont have the STI but i do have 2 EVO 3's and they are more than capable of coping with a tight infield, and then have the ability to make a OS look like its standing still on the straight. After trouncing the field last year with my EVO 3 everybody else was sick of getting slughtered down the straight and through the infield so all bar 1 guy now have EVO 3's.

So i am sure that the STI will be even more capable of what you want.

Cheers Daniel

I ran my STI on quite a small track with no lack of power anywhere. With the right pipe (as well as what Robert said about clearance etc...), the STI can handle anything.

Dave

Thanks guys

Oh and about the whole crank pin issue. I read on 3Hobby.net that crank pins seem to be breaking on the EFRA legal STIs. I bought the IFMAR STI from Murnan and have yet to break anything.

Dave

yes i know you do thats why im faster than you LOL

mine was a ifmar sti

Maybe the breakage of cranks should be caused by something during the break-in... what temperature get the engines during the initial tanks?

After time, people still continue breaking Sirio crankshafts, but... what amazes me is that some people break them and some people not... something should be wrong with those break-in procedures.

People still use them like Novas, and run them at Nova temps... but those puppies like more heat (around 100ºC over air temp is a good ballpark figure).

Here are some links explaining various aspects of metal fatigue. I realize that these are rather academic, but they may prove helpful in discussing the breaking crankshaft problem.

- http://en.wikipedia.org/wiki/Fatigue_(material)

- http://materials.open.ac.uk/mem/mem_mftext.htm

- http://www.epi-eng.com/BAS-Fatigue.htm

- www.engr.ku.edu/~rhale/ae510/fatigue.pdf

i think its just when i rolled the car and crashed hard,i know ppl did it with a jp too. i think the crank is too hard,i break it in just like all my other motors. the motor is very fast but you just have to be careful with it,its just like real motors high HP you may have probs if your not careful,but i still like the thing it sounds so cool LOL

Anytime the engine takes a direct hit, there is always the possibility that the energy of the impact is going to ripple through the engine and break something.

Now that I think about it...

Depending on the circumstances, one might get the impression that a crank broke while it was just on the starter box, running on the track or involved in a minor impact, but it might be a result of metal fatigue, that was initiated by damage sustained in prior crash.

BTW Wally, How are you breaking in your engines?

yes this is what i think happened and i do the josh way and i found it realy works good,even when i change a piston and sleeve on a old motor,the motor is faster and is just better than before.

I think Wally uses the Cyrul method. I used Cyrul's method and am well into my second gallon of fuel on my STI.

Dave

yep and you dont hit anything hard ether and yes your motor is fast after we got the gearing wright

oh i will say here a nova motor with a micro piston i break in a little diff,i only run it on the box for 2 tanks then i go on the track,the sirio piston is cnc so it takes longer to break in

Any comments to RCPANAMA's post in the 720 thread regarding the STI? Agree? Disagree? Thanks!

http://www.rctech.net/forum/showpost...postcount=1368