i meant the diameter of the extech adjustable clutch flywheel is smaller than the regular mugen flwheel

after seeing the X-Dyno results on these even after modified its clear Sirio has fallen short like they do with almost all of their off road engines. Ill stick with the VSPEC.

+1 Mr. Joe

+1
this engine is a huricane

+111111 ,,,,, all i got to say that this motor is by far one of the easiest motor to tune if that , i broke in my buddy's motor for him 2 tanks heat cycled at 240deg , a 3rd tank sitting on the starter box (heatsink uncovered) , 4th tank
small burps around the backyard (no needle adjustment still) ,5th tank hsn lean out to 213deg and balls to the wall with it
7 tanks on it and needle settings still pretty close to stock how i got it out the box, ready for supercross this sunday @ rc amdness , enfield ct.

????? I never do unterstand these comments were someone get's caught up in the dyno numbers. Last week my Extech powered XT8 was running along side a VSpec powered truggy and I would gain on the straight on him. The extech has a smooth strong low end depending on what pipe your running compared to the vspec that's spinning tires, but when he's pulling in to pit I'm still making laps.

In the last 2 years I've ran Go motors, Vspec's, MR Ninja's, Novarossi's and Extechs and by far the best motor has been the extech in terms of fuel economy and power.

also, whatever you do, you never seem
to get them overheated

I know what you mean. Alot of people like to get caught up and jump on the "dyno is just for numbers bandwagon. Trust be told the dyno tells you exactly and consistantly what power your engine is making. It also tell you where its making all of its power. This is very usefull. The bes thing about a dyno is that it tells you the most important thing about an engine. Area under the curve.

Ive also noticed that just about everyone has XXX engine that blows past XXX engine. How do you know how well that engine is setup, running and tuned? you dont. Any engine can be slow. Its making them fast is what takes skill.

The Vspec is the best off road .21 ive ran into. It makes .28 power and actually holds the power in the top end. It also likes to spin RPM and sips on fuel. If course i can take the same engine and put some crap fuel in it with a JP3 and the wrong clutchbell and get dominated by a RTR engine.

The extech is OK at best. The RACE PREPPED EB Mods one only made 1.38HP on the xdyno(the same dyno EB has) Other than that this engine holds the power for a little bit in the upper RPM range it doesnt do it as well as even a stock VSPEC. for 450 it just seems your paying for a name. That money could be spent much much better. You dont haft to listen to me i understand you have your pride and all.

XRC just released the dyno of this engine. I'm sure thats where German got the information. I also have an X-Dyno and would be glad to test it myself. I haven't messed with ANY settings that BK put on my Dyno so I know its right and un molested just as he designed it. Although my Dyno tends to read lower then XRC and others that have the X-Dyno its consistent and thats all that matters to me as I use it for R&D.

I know if Derek or BK did the test for XRC you can guarantee the test was done right and I would trust the results 100%. And there usually the ones that do the X-Dyno testing for XRC mag. And with BK being the one who designed and produces the X-Dyno I dunno how you can even question his results!?!? He has no biased twards anyones engines... And unlike some he's not on here pushing a product because hes sponsored or his friend modifiys these engines etc. No pun intended BTW. That is one thing thats bad about forums is the biased comments, and then when there questioned or someone disagrees the bad attitude that follows.... I dunno why everyone just cant be civil and not have to feel like they have to argue it seems... if you like the engine and you feel it helps you win races then thats great! Thats what its all about! Everyone has there preference on what engines they like and dislike, so why even argue over it?? Just run what engine you like and be happy and have fun racing! No need to try and talk down to others that dont share your opinion.... And im not calling anyone out, so I dont need the "hey u hurt my feelings coments " Im just telling it like I see it on these forums all too often.

I'm sure the EX Tech is a great engine that will win races, but so are alot of other engines in the right hands. I'm not here to argue in anyway shape or form as argueing on the internet is as pointless as smacking yourself in the face IMO My point is we all shouldnt be so biased... Be open to discusion and dont hate on others. You'll find that it gets you alot further then arguing and having a biased attitude.

What dyno are you referring to, and if so were both motors done on the same dyno under the same conditions? Because if they weren't this argument is pointeless, when I raced sand drag quads there were constantly people posting there dyno sheets from dynos all over the U.S., but unless you run them on the same dyno there are to many variables to make comparison to.

I run the extech and i love it its a beast to say the least and i finally thinks its broken in cause now it will idle all day long! I also have run Rb engines in the past and they are great as well. I have also hear that the C6BB did not Dyno well? These dynos are crap compared to track time and expierence! I know my extech has plenty of bottom and pulls the straight just as fast as any engines where I race and its not the modded one! Just like when i ran the C6BB it was always one of the beasts at any track I went too. The dynos are not a accurate way to rate engines!

Do the none tuned versions of these do well in a truggy?