I feel as though if Mitsubishi cared that much about NVH, they'd have put more money into noise suppression and cabin isolation. The Evo is quite a harsh car compared to many others on the market. Mitsubishi wasn't trying to make the Evo an average consumer car, they just needed a car to homologate for their rally team with the added benefit that sports enthusiasts would love and buy the car.

Again, it seems like a lot of added expense for very little benefit if the only concern is NVH, especially considering many on this forum with BS deletes did not notice much of a change in NVH after the removal.

 

its almost like we are arguing about how deleting the A/C compressor is bad for your engine.

 

Does anything think that the WRC cars ran balance shafts?

 

I don't think that's a fair comparison. I think the big argument here is, are 2nd order vibrations causing accelerated wear on components? If they are not, then sure there is no need for BS. However if they're causing even a 10% increase in wear, I see the BS as a worthwhile component to keep in your average high-mileage daily driver engine. This does not apply to racing engines that will be torn apart every year anyway. At that point it really doesn't matter and I'm all for removing the BS for simplicity.

 

If balance shafts reduced wear I think every MFG would use them. Warranty claims hurt the bottom line and reliability problems hurt the brand. Also Mitsu doesn't use them any more.

 

Mitsubishi's WRC spec sheets never listed them as being removed, however I can't find any concrete data that they where retained. Maybe we can ask Tommi? :P

 

I already pointed out that Mitsubishi did not use balance shafts in every 4G6x, nor did they use them in every 4 cylinder they produced. It is on the same lines as why they didnt give us the 8 disc clutch in the rear diff that the rest of the world recieved....Americans are candy *** whiners. "Its noisy, it clunks, its vibey"

Entirely overcomplicated the reason for deleting them it seems. This isnt a bridge, it wont go and doesnt go galloping Gerty. I am also not going to post pix of engine parts from inspection. Sharing knowledge on this site has only ever cost us money, never really brought anything of benefit. Suffice it to say the wear you seem to expect isnt there, a race engine would exacerbate the issue not hide it because of lower mileage usage.

I have seen the inside of a WRC Evo engine...including the CNC outside they machined to save weight.

 

Mitsu doesn't use a BS in the newer 4B engines because the aluminum block does a better job of dampening these vibrations. It may be a different story in our iron block 4Gs.

 

That's an unfortunate way to view the community that supports you so whole-heartedly.

 

This is why there are "supertooners" and everyone offers a 2.2L stroker now. I literally gave business to everyone else because I shared how to do it correctly.

 

If that was your only take away from that entire paragraph then my work here is finished.

 

I respect your experience and you clearly know what you're doing, I'm just asking for a bit more hard evidence than what you're offering. I have yet to see solid evidence supporting either side of this argument and that is the whole purpose of this thread.
In a perfect world we would have two engines, built the same way by the same person, one with a BS and one without. Then examine wear on both of the engines. This would go much further to support the claims being made in this thread aside from "I've built 1000s of engines without balance shafts and have not noticed accelerated wear". I'm only interested in building engines that will last nearly as long as the OEM factory build. If balance shafts have an impact on that I don't want to remove them. I admit that I have not seen evidence to suggest removing them shortens life, but I've also not seen any solid evidence that they do not which is the point of discussion.
If you actually where to post some comparisons in engines that you've personally built, that would go much further than simply stating something is fact without any deeper explanation.

 

What your asking is for proof that deleting the balance shaft doesn't cause wear, but what about flipping that around. What proof is there that it does? Like I said before, there are plenty of balance shaft related engine failures. Where are all the folks with engines that failed because of deleted (properly) balance shafts. For me the score has been and is still deleting the shafts improves reliability not hurt it.

 

I'm open to proof from either side of this argument. That's the whole point of posting a discussion thread. Saying something is fact without going into detail about why that is does not benefit our collective knowledge in any way. I just want to hear some solid evidence supporting either side of the discussion. Not looking to argue for the sake argument.

 

Just to add on top of this whole conversation, the Mazda skyactiv-g 2.0L motor doesn’t not have bs but the 2.5L does. It’s just because the larger displacement motor created more unwanted vibration at certain RPMS that’s why the engineers put them in for the 2.5L. They are not designed for the entire rpm range . They are just belt , gear or chain driven and forced to spin at all rpms. I wouldn’t concentrate too much about where the piston is positioned compare to the bs other than if your checking if it’s installed correctly or installing it back or changing the belt.

When I removed the bs on my 2003 Sentra ser spec v many years back , I only felt vibration at 3500-4500 rpms area only . And it was not that bad with stock motor mounts .