Excuse me if this has already been brought up, but I haven't seen anything on it.
I have a 99 Civic EX (EJ8) with a blown Y8 motor. A bad input shaft bearing on the tranny threw everything off noticeably for 30-50k miles, and at 205k, one of the rod bearings went kaput. I have a couple of other vehicles now, so the Civic has become the project car.
I have been considering putting an iDSI motor from a Honda Fit or Jazz in the Civic and then doing a bunch of aerodynamic modifications. I would really like to get a 1.3L motor from an overseas Jazz (why don't they sell these over here, hmmmmmmm?) but would settle for a 1.4L or 1.5L. Has anyone done this or anything like it yet? If so, what have been the biggest difficulties? Axles? Mounts? Wiring?
Dealing with emissions could be difficult. Why not get like a 1.7L honda D engine or something and turn it into a stroker or something? With that engine, I think you could have a custom camshaft fabricated so that the intake valve closes a little late in order to reduce the effective displacement but still allowing for you to have the same stroke which would give you more torque over an engine like the 1.6 or 1.5L D series engines.
The reason why I'm saying this is because while I too had the same idea, I later realized that it makes more sense to have a car with a decent amount of torque in the low RPM range than to have it scream in order to get going anywhere. Also since the newer engines have more strict emissions, you may not get as much performance and fuel economy out of it as one would like.
My plans are to take the head from a D15Z1, combine it with the ECU of a D16Y5 and put the head on either the block of a D16Y5 or block of a D17A1 and use that combo in a '96+ Civic. Even better, after being done with smog, I can swap back in the D15Z1 ECU and use it with that same engine. I'll also attempt to boost the compression ratio in order to increase the efficiency of the engine. I might play around with the fabrication of some cams or whatnot, but we'll have to see..
That's a good idea, *************, but I question the concept. Honda has pretty thoroughly proven that the best fuel economy comes from sacrificing torque and having to rev way up to get it. I assume that this is because you then cruise more efficiently, not having to turn a torquey engine so much, instead turning an easier-to-turn engine.
Personally, as much as I want fuel economy, I would usually choose a little extra low-end torque. That's what I love about my VW. It's also great for hypermiling; it's easy to beat the car's rating when you've got a lot of torque waiting to be used...though at over 150% of my car's rating I'm probably still not beating a Civic VX's rating.
Well the problem is, we don't have any dyno charts of the VTEC in action so we don't really know what kind of torque numbers Honda put out at 1000 - 2000rpm. Keep it mind that since the VX supports lean burn, if you could get the engine to be really torquey under high load at low RPM (not in lean burn), then when you're cruising on the freeway and the demand is low, the ECU can lean out the mixture. Increasing the compression ratio or at least the dynamic compression ratio should also make lean burn that much more effective since you'd have more fuel closer to the spark plug. The only Difference between the Honda D or EW engine with the 1.3L engine from the mid 80s and the 1.7L Honda D engine from '01-'05 is the stroke! Which each successive 100cc of displacement increase, there has been a 10ft-lbs of torque increase. Also for each increase in displacement, there has been an increase in compression ratio. The reason they're able to increase the compression ratio at the very least is because of the longer stroke which distributes the heat over a larger area.
An oversquare engine allows for more and larger valves in the head of the cylinder, lower friction losses (due to the reduced distance travelled during each engine rotation) and lower crank stress (due to the lower peak piston speed relative to engine speed). Because these characteristics favor higher engine speeds, oversquare engines are often tuned to develop peak torque at a relatively high speed.
This can be a negative trait, since a longer stroke usually results in greater friction on the cylinder walls, more stress on the crankshaft, and a smaller bore requires smaller valves which restrict gaseous exchange. An undersquare engine usually has a lower redline than an oversquare one, but it generates more low-end torque.
So really, Honda engines actually do produce quite a bit of low end torque, it just depends on what kind of Honda engine we're talking about here.
Anyways what I was trying to get at with the custom camshafts was that you could make the engine more like a Prius' atkinson cycle engine, so that while the engine has a high geometric compression, in reality it's not that high and the purpose of that is to increase torque.