Ok, that is resonable. I still would like to see the difference in engine lifetime between both. Oil pressure shouldnt be too far off from factory, especially if you use AMS's removal kit. (which I am)

 

This is correct. I stop taking balance shafts out of my own motors years ago. The vibrations you pick up are simply not worth it. Your dash and interior will pick up rattles. And even your exhaust will be louder. Those who say taking them out is not that noticeable are not very observant. Stock block record is over 600whp. How much HP can they cost? If you have a drag car take them out by all means. Most venders are gonna recommend taking them out because that is one less thing to fail in a high HP car.

 

I've always seen it not as a power issue, but a failure issue.

 

On a stock(ish) setup, I had removed the balance shafts and picked up more horsepower (5whp) and a lot more torque (20wtq). As far as I'm concerned, that was just one of the side effects of removing them as I did it to eliminate the possibility opf failure and for weight savings. At idle on that setup, I picked up more vibration in the upper mid to high range power, but at idle and everywhere else, no.

On my 2.3 liter setup, I balanced the rotating assembly prior to installing it and have had NO OVERLY EXCESSIVE VIBRATION. THis means that yes it vibrates a little, but not near the point that it's shaking anything loose. THe key to this is that I spent the money and time to do the swap right an didn't half a$$ it by trying to cheap out and not balancing the parts. ANd yes, the car is daily driven.

In closing, I think it's crap to hear the complaints about vibration when doing this. If you're that bothered by the possibility of feeling your engine, sell your evo now and by a lexus.

 

I'm not complaining about the vibration I'm feeling... I'm just trying to understand if it is normal and what causes it. And also, I think it might be helpful to people thinking about stroking and no balancer shafts to understand the motor should vibrate more... and how/where/when they will feel it.

So for people who have gone this route, I'd love to hear about where and when you are feeling this extra vibration. At idle? At a certain RPM? etc

 

There are going to be many varied opinions on whether removing them produces annoying vibration or not. Its just like talking about laggy turbo setups. Some can deal with it and some cant. My 2.4 sans BS that was in my yellow car was as balanced as an engine can get. including the clutch, flywheel, and after market harmonic balancer. I didnt think the vibrations the engine had were that bad till I built a 2.3 for the car WITH balance shafts. The before and after was quite stark. dash rattless disappeared. And more amazing was how the tone of the exhaust was much softer. I had pretty much the exact same thing happen in the blue car. Going from a 2.0 sans balance shafts to a 2.3 with shafts. The dash rattles were atrocious in that car. and completely gone with shafts.

Another important point to make is the amount of rattles you pick up is directly proportional to the type of engine mounts you have. stock rubber mounts are the most forgiving, which is what I always use. I have driven a car with hard urethane mounts that vibrated the rear view mirror so bad it was useless.

modding cars to go faster is fun if the car is still enjoyable to drive after you mod it. making sacrifices in driving comfort is very easy to do when making your car fast. before you know it your car can become a complete ***** to drive.

 

+1

All it takes is for you to snap a balance belt once and have it to take out the timing belt for you to realize its not worth it.


Could the extra vibration have been caused by balancing the aftermarket harmonic balancer? Many companies (ATI, Fluidampr, etc.) recommend not balancing the assembly with their harmonic dampner in place.


I don't use balance belts in any engine that I build and I don't find the vibrations to be any worse than most sports cars out there. In fact, I would say that my C5 vette is worse than the 2.3l at idle w/prothane bushings.

 

Good info 94' et al but....

Nobody is actually explaining how the vibrations manifest themselves. Specifically, do you feel it only at idle, or at higher RPM's? I happen to be feeling an extra amount of vibration or resonance between 3-4k rpm. It is a high frequency type of vibration... not a judder. I feel it in my fingertips and feet (I drive barefoot cuz always wearing flip flops). If I knew this vibration was normal and ok, I'm quite sure I'd forget about it as it is not annoying but just there.

So I'm trying to figure out if this is normal. Yes we all agree more vibration than stock 2 litre... but please describe this vibration.

 

It was already described as being twice the frequency of each cycle. You can rest your hand on the valve cover at idle and you can tell if the motor has balance shafts or not. One will vibrate your hand and one will not. The vibration is felt through the entire rev range. But it is most noticable between 3500-4500rpm.

 

most pronounced at 2500-4000rpm
I wanted my stroker with a balance shaft but the 2 shops I considered at the time AMS and Buschur will not built stroker with a balance shaft.
My advice to those considering a stroker but is unsure about the vibration issue is to test drive a car without a balance shaft first do not just listen to SUBJECTIVE comparison only.

 

reread my first post to you.

 

I would assume its possible to build a 2.4 liter with balance shafts, has anyone done this? Most of my DSM buddies get rid of the balance shafts but they are hardcore drag racers and 99% dont daily drive those cars. I only ask because I have a 2.4 liter block im dying to drop in the EVO but I drive it everyday. I happen to agree with 94AWD............I want my car to feel good as well as run well. Im the kind of guy that gets pissed when the CEL comes on, makes the car feel like a poop box.

 

I build 2.4 and 2.3s with balance shafts. The original shafts from the evo or from the 2.4 block will clear the longer stroke. (you have to use shafts with cutout to clear crank throw.) I recommend they be nitrided along with the crank. Makes them far less likely to fail.

 

you have absolutely NO idea what you are talking about...


jk

i feel strongly about keeping them... the 2.3's we have done with the shafts purr so nice...

cb

 

the mechanics of the inline 4 of all engines of different brands, companies and models will have vibration which is inherent of all inline 4's. that is why mitsu developed the balanced shaft and which was subsequently copied by porsche when they were still making 4 cylinder engines. inline 6 and V6-V8-V10-V12 are perfectly balanced in terms of engine harmonics that these engines don't need the balanced shafts. mechanical engineering 101.