Which engine to use?

[GT-squared]

Ok, so since getting my missing crankshaft pin spring thanks to some of you guys on my last thread, my freshly ported/polished 4.1 is almost ready to go.

So, here is my debate. I've got my K4.6 out anyway waiting for a new roto-start assembly coming in tomorrow at my LHS. What do I install?

The modded F4.1 or the stock K4.6? Which is going to be the more powerful engine? Has anyone had the chance to try both personally. The other will simply sit aside as a spare or go into my next project if ever.

Opinions?

 

[Shaun]

I'm not sure myself which would better but i know i watched a vid of purenitro's modded 4.1 and the front wheels barely touched the ground lol it was insane after the mod!!!

 

[GT-squared]

HHHmmmmm. Going to be a hard decision I think.

Oh, and if it makes a difference, it's going in a stock Savage 25 chassis.

 

[Mickey]

i would try both but i think the modded 4.1 should have better top end

 

[Larsenracing]

To tell the truth, one of the best engines I have ever ran was the F4.1 It liked to run at a worm temp but it ran great and had nice power for what it was. I'm far happier with the way that ran over the 2 Axials my savages have in them right now. But not for long they will get new motors actually the one will get the Picco and the other will get the Mach 427 I modded.

 

[Grumpy1822]

I don't know who modded your 4.1, but most modders net about 20% hp gains. That 4.1 in Robins vid is an exception. That was beffore he was known and he had way too much time on his hands lol. That thing is also modded to the extreme. Longevity was not one of his concerns. I'm putting words in his mouth though, better ask him directly.

Back to the question at hand, a 4.6 will walk all over a 4.1 with a 20% gain. No w Robin can mod your 4.6 for you and give you some real noticeable results and keep it going for a while. He specializes in those engines.

 

[GT-squared]

Well, I modded the 4.1 myself, and no, I didn't go crazy. I did all the stages that were in the .pdf in the sticky, but I didn't got over 165 degree rotation. I didn't want to get into modyfing the block much.

So, if a K4.6 will still be the more powerful engine, I'll keep the 4.1 as the spare. I don't really care about a big difference in top end, but power(or I should say torque) is really what I'm after. I like to be able to pop a wheelie without effort when I want. The stock 4.1 couldn't do that. It should definitely run hard on the top end however since it will flow a LOT better now with the mods.

Since there's no replacement for displacement, I guess the 4.6 it is for the win!