Nice run! little beast.
I'm going to try a sportwerks .26 (a.k.a. mach 427) it pulled 40k in my buggy.
It's modified and has a bigger carb. than what it came with, want to see what it can do in a lighter car.
I still have the old faithful flash 21 in the pocket and another flash p/t rally both 35 plus based engines. they are little monsters as you know.

Yes, the onld 21 flash was a beast. I have one sitting up waiting on another roller.

Whats up everyone? I haven't been on here in a while and haven't had a chance to go out and test but heres a video i shot about a month ago with my new Murnan motor. It only has a quarter gallon of fuel through it so not much gearing. I've made some changes and found some more power so hopefully ill be able to test soon and get that 120mph pass.

+ YouTube Video

I would use the HPI k-5.9 Nitro motor.
For the transmission HPI 3 speed is good.
But the 3 speed from engineDIY might be better.
They make a kit to mount 2 separate Nitro motors side by side.
also RD innovation makes a super charger that will add up to about 27% power/boost.

I don't know about you. But for me when I get to the RC meet while most electric car owner are charging up batteries for an hour Im on the track running my nitro car and having fun.
I have electric RC cars. And I hate charging batteries. When you spend all day at the event you don't want to spend most of the day charging.
I see people there with 4 or more chargers working their buttons off just to keep up with full batteries. And the cost to have a set up to do all that cost 3 or 4 times your car cost.
A good 4 port lipo charger will cost you a good $300 and for 4 7200mah 50c 4s batteries will cost about $150 each.
now you have about a $1000 in batteries and charger.
I can buy a nice RC car for that.

Just my 2 cents

Why do people think that bigger is alwas better?

That HPI motor may have torque but no top RPM. 3 speed sounds nice but is heavy, that is why all competition cars are runnen 2 speeds which is with competition engines more than enough. And why would you use any crappy supercharger with vague powe gain claims if you can get more air with just more nitro in the fuel?
And why not modify the engine?

If you give advise then please, know what you are talking about.

Well let's see do I know any thing. YEP I do know this, more displacement in a fuel based motor means more power. More power means more speed.
And how do you get more displacement. By making the chamber larger. By using a bigger motor, or bigger cylinder/piston and rod plus crank rotation.

Ok I guess I do know something.
Does bigger always mean better. Nope.
Is electric better than nitro. Nope
Is nitro better than electric. Nope.

The fella ask for an opinion. I gave an opinion on what he can do or look into.
it wasn't facts.

Now that last statement about you get more air with more nitro in your fuel. Well ser your wrong.
you run 20% nitro in your rc car. At tuned it runs great. Now you run 30% nitro and you tune it and it runs even better. Right.
Right.
First of all your not pumping more air in the chamber. You still have the same air intake but more combustible nitro and less oils per volume. All fuel based motors are just air pumps. You didn't change any thing but fuel.
so this motor has a carb. Let's say it has a venturi of 8mm, and the horn is 13mm. This will only let so much air to go through it.
now we put a bigger carb on it. Let say we goto a 9mm venturi with a 15mm horn. Now more air will flow through and once you tune it for this more air you guess it more power..
So look at it this way. Get a coffee straw and suck water through. You don't get much.
now get a soda straw and suck water through it. Way more water.
so I guess i am wrong bigger is better, and more power..

This is coming from a guy who races real cars and build real top fuel motors.
Thats my 2 cents.

I have my bag of popcorn ready....
Just finished my "really thin pancakes".

Yep, you know it all.... So you know that what makes a good engine is more than only a displacement.
As with 4 stroke engines you can modify the cam shafts for more performance you can do the same with 2 strokes with the port timings and with the crank shaft timing. The HPI engine is a cheap Chinese produced egine so by default the engien is lower timed so the engine will stay alive. Of course you can open up the crankshaft, raise the ports and drill up the carburator but with the 1st run the engine will shatter in pieces due the chosen weak materials.
As you are probably known with tuning parts like 7068 aluminum rods to even titanium and special light weight pistons (wich with 2 stroke are almost impossible) we do not have such option parts for a cheap build HPI engine.
Competition engines are first of all much higher timed, many of todays onroad competition engines can hit almost 50.000rpm while the HPI will not even reach the 40.000 rpm but maybe 35.000rpm. But second of all, the used materials are well chosen to withstand all the high G-forces at such a RPM range and there is even room to do more with open up the timings.

On youtube amoung bashers there is a buggy .28 challenge going on, who can reach the highest speeds. For one of those guys I have done an old Novarossi based .21 (!!) offroad engine. I did gave it an onroad competition spec timing with a tiny bit more degrees timing an managed to gave it 2 extra small exhaust ports. He did reach the 100km/h goal he wanted and that with still the stock 9mm carburator and pretty normal 25% nitro. That is more than all .28 setups up on today in that challenge have done.

So yes, I know a bit about engines too but maybe that is because for about 10 years I was involved with the devellopment of such RC engine. Not only as testdriver played with timings but also with a clear insight of material choices and designs of shapes and other stuff..

Should I get my own popcorn? Or can you share, Im broke, used all my money on tires...

You bet. I'm still using tires from the last worlds....

I can't wait they hit on 80% nitro, or which clutch is better, then, which chassis is best...I love fender lizard chatter!

Fastest on track with roar rules is what counts...Anything else is for the movies....

I would pay $20 to see this guy and his pullstart HPI engine race Roelof with a race .21

You never really know what's faster until you race them.

does it really make that big of change to it?

Well Hell lets slap a 5.7 hemi in one of those little bad boys and see how that works.