you cannot run pulleys without dampeners... the crankshaft twang when unchecked will weaken and eventually destroy the crank.

 

Try but the Evo doesn't have a dampner so to speak. Just a lil piece of rubber that keeps the slight vibration from bothering you. I have been running this crank pully for a couple years now, it is fine. People have been running them on DSM for a lot longer. Just make sure that it is balanced properly.

 

i believe some people in the upper echelons of dsm racing broke cranks when they went to pulleys...

 

It still would be nice if they put a dyno graph w/ and without to see the difference.

 

The stock pulley has rubber for a reason which is to absorb vibrations which kill bearings, not to keep vibrations from bothering you. I have seen people on stock motors throw rod bearings using aftermarket crank pulleys.

 

Listen man, you need to realize that optimizing an engine package is not all about power. Its about NVH, cost, reliability, packaging, emissions, as well as power. That being said, there are things like the crank dampner (crank pulley) that may seem like under-engineered, over-weight parts, but in fact they have tons of development time, design time, and endurance testing time completed before production. Rest assured, everything on the 4g63 is that way for a reason. And do you think manufacturers would be f-ing around with DI, all kinds of cylinder swirl mapping, variable volume intakes, etc if they had 10 free hp sitting under their nose? LOL. No.

Ive talked with various engine gurus at OEM companies about the crank dampners actually, and they all said they weigh as much as they do to protect the seals and other engine components and are VERY IMPORTANT.

Take it for what its worth.

And btw, 42k is nothing for an engine. If you avoid seal or bearing failure after 142k, drop me a line, id be interested then.

 

I agree somewhat. In reality most cars have some parts over engineered, there is sometimes a margin for improvement, although at the end, it is most likely to reduce engine miles. The trade of will be, Are you willing to give up a few thousand miles for a few ponies?

 

The pully debate is quite a weird one. Some tuners SWEAR by them and they do infact show an improvement in power and low end power. Some swear that they will kill your engine so fast, their is no middle ground. I ran one on my DSM for years and on my Evo for 2 years, worked great, aided in spoolup AND low end and added about 10WHP across the board with a 15WHP spike twords the end.

 

Ok, but the topic was that if Mitsu COULD have produced more power reliably they would...obviously that is not the case now. If we are going to talk about noise etc etc then you can't say that there is nothing else Mitsu could have upgraded to make more hp reliably because there obviously is.

 

I read a very long tech article on pulleys quite a while back, forgive me if I don't explain it too well. Basically there will be a certain frequency of vibration that will cause damage to the engine. These frequencies aren't very large in range, and usually only occur at a certain rpm. The dampeners are there to eliminate these certain vibrations in these rpm ranges. In order for these frequencies/vibrations to cause damage the engine would have to stay within their range for an extended period of time. Since this isn't common, except for maybe in road racing, then aftermarket pulleys generally won't cause any damage. This is why people running with pulleys for many thousands of miles aren't seeing any ill effects, because these "harmful frequencies" are rarely seen in day to day driving. Also when drag racing you will be within their range for a very limited amount of time, thereby not running long enough at these frequency vibrations to cause damage. Oh yeah, I didn't specifically state that this happens in the upper rpm's, but I think you would have gathered that anyway. If I remember right every engine is different as well as to what frequencies would be damaging, so you can never be too sure. These damaging frequencies could even occur above redline, so you would have to worry about it even less then. At any rate the rpm range for this is VERY short.

In my opinion, after reading that article which outlined pretty much what I said above, running aftermarket pulleys is a minimal risk. Now if I were running any kind of road racing, time attack, etc. then stock pulleys would probably be the way to go.

I hope I helped clear up some things for people concidering aftermarket pulleys.

 

So what is RPM and Frequency the stock damper is tuned for?

If you don't know then the article is kind of pointless. What if it is 3500 RPM on the Evo? That would mean you are often in this range and doing damage.

Ask any good engine builder and they will tell you the importance of a good damper.

Whoever said some shops love them and others hate them you need to remember that some shops know what they are doing and others don't.

 

Actually I don't think the article was pointless, because it can point you in the right direction. If the information is out there, then I'm sure it could be found, regarding what rpm these "damaging harmonic frequencies" occur.

I'm no engineer, so I have no freaking clue. I just don't worry about it. Personally I think everyone is just too paranoid, and often do other things to their cars that could be far more dangerous.

Do what you will, I'm keeping mine.

 

Good point timzcat but again many people have run them for years and so have I and only gotten positive results.

 

Exactly. Also remember some shops build cars to extract power and advertise numbers. They can rebuild the motor more often then you can get a hair cut. I have had a DSM for years , now the EVO and I would never run a pulley without a harmonic balancer (dampner) etc.

 

Your kinda missing the point. Any OEM can make more power with a particular engine. Take the GM small block: a more aggressive cam yields a ton more high-end power. You can make the same argument for any engine. But the thing is, there is always a trade-off. With an aggressive cam, you get a crappy idle, less low end torque, and you may run into emissions problems at low speeds. Everything is a tradeoff.

Those saying underdrive pulleys give more power are acting like their is no tradeoff...that putting on an aftermarket damper is just free horsepower. Im sure mitsu could have comprimised fuel economy, idle quality, low end torque, etc to make more power up top to please some customers. But there isnt anything on that powertrain that is under-engineered to the point where it can be modified for more power without any reprocussions.