Thread: so, how balanced are SR20's?

To start out, I've had expererience with many Honda's and Toyota's, and my SE-R (with approximately 70 thousand miles) is nice and torquey, but above 5K rpm, it isn't very smooth. Not that it's very loud, and it's not about the motor mounts..it's just in the higher RPM's, it feels like the internals are not in sync with each other and the engine's vibrations basically vibrate everything in the car compared to other 4 cylinders.
It somehow feels like the SR20 wasn't meant to and doesn't like to be revved too high..It's just not as refined as a B series or even a typical Camry engine. Is this a sign of deeper problems (rods/ rod bearings?) or is the SR just not up to par with other motors as far as rod/stroke ratio, crankshaft balance, etc.. is concerned. I'm obviously exaggerating the problem and it doesn't seem like the engine's gonna implode, I'm simply paying more attention to the detail. just curious how you guys feel about this and how you'd compare it? Is my motor just an oddball(at 70K miles)?

The SR20 doesn't have any balance shafts. From what I'm reading, the B series Honda motors don't either...

I've driven an RSX type-S before, and know what you mean about the Honda engine smoothness. The SR20 is down-right harsh compared to a BMW straight 6.

It's normal. Everything is fine. Nothing to worry about. Enjoy the torque. =]

it depends on a lot of sh*t... if they don't have balance shafts like ben says they will be much more vibraty...

we could figure out the balancing if you really want lol

but it would be hard to do without having one apart for measurements

what is the "lot of sh!t" you're talking about? If the B series don't have balance shafts as well, why does the B16A rev like a freakn sport bike and is so smooth while doing it and a regular Non-Vtec B18B could chill at the 7200 rev-limit all day without a hiccup. It may be the rod/stroke ratio, but what else? why does it seem like I get more worried about taking the SR over 6.5K on a regular basis?

There are plenty of things other than balance shafts that influence vibrations man. And for the record VTEC has nothing to do with it. rod length and crank throw, alont with cylinder firing timing and order all have a ton to do with it, as well as how the crank counterbalance weights are set up...

I redline my daily, and I don't have a problem, yeah theres more vibrations but maybe something else is wrong with your car??? I've never been scared to take my car to 7500 before. maybe some bad bushings in your suspension?

IF we really wanted to figure out the balancing it would be a lot of work.. trust me on that one..

But I wouldn't worry about it.. it's obviously balanced well enough to last 200k miles + more

That was my point... a non-vtec B18B or a B20 (CRV) compared to an SR20 is an apples to apples comparison. What are the inhererent faults to an SR20? obviously, the rod/stroke ratio of a B16 is ideal, but you'd also think that .5 liters of displacement per cylinder which is ideal would be a benefit to the SR. what can we do about crank counterbalance weights that aren't set up right?
what alternatives do we have as far as aftermarket parts for the block without balancing and blueprinting the whole engine for several thousand $$.

LiketheMovies..I take mine to redline just about everyday..and I've had it for 3+ years..but my very first impression was that it didn't feel as smooth as my previous cars and driving my friends integra this past week made me realize it even more.

also... 200K is good, but my old honda has 340K on it, I took it to the drag race track just about every 2 weeks, I drove it very high spirited daily..and my parents still use it to this very day as a daily commuter without any evidence that it ever lived through the abuse I dished out on it.

I'm just trying to have a semi-technical discussion about the SR20's inner balance, and a way to negate all its weak points.

yeah its not as smooth as other engines but it still enjoys to be reved high, it likes it even more with aftermarket cams such as the jwt s4's mine gets reved out to the 7750 rev limiter all the time, mainly cuz in first and second gear it will just pound off of it when i punch it, but its a whole different ballgame, it really depends on the setup, the sr has pretty big bores and a decent stroke to go with it, it makes a difference.

Now the VE motor with the 4CW crank is probably quicker reving and smoother because of the lighter crank and internals, but most people that are going to rev up to 9k use the 8CW crank found in the de/det motor due to the fact that its more balanced, may not rev as quick but its safer for high rpm due to the extra balance.

i honestly dont think that the b16 is all that, yes it revs high, but it has 1.6L and makes no torque, the sr20 is more than par, as far as far as turbo a sr20de, it has LOT of potential before needing to be reuilt, reving high isnt ALL THAT, and dependig on the setup, reving high ISNT always needed, nor does reving high mean more power, after a cetain point ifthe motor isnt reworked for that higher revs and more air flow you arent going to see anymore power than stock rpm limit.

personally, my sr20det is roation assembly is balanced,bueprinted,lightened, my reving is VERY smoothe and the boost is SEEMLESS. and my setup isnt seeing anything higher than STOCK rpm rev lmit, and its built for way higher than stock limit, but my setup just doesnt call for HIGH rev, but that is prfectly fine.