OHV = OverHead Valve = pushrod directly actuates valves.

As opposed to OHC = OverHead Camshaft = cam directly actuates valves.

Wikipedia is your friend.

I'd say I've got the OHV,then.

I agree. My dad's 83 vw westy weighs a lot and has something like 84 horsepower. The only time this is a slow vehicle is when you start out on a steep hill. It's adequately powered and maintains 70mph easily.

People think they want power but they don't realize you don't need much. In Europe small cars can come with 1.2 liter engines. In the US, if you want a vw rabbit, you get a 2.5l 5 cylinder. Isn't this overkill?

horse power is always peek horse power and that peek is around 5,500 - 6,000 rpm on most civic engines, the peek torque on the other hand ranges between 3,000-4,500rpm, the cars that get better mileage tend to have better torque and at lower engine speeds like the crx hf had peek torque at around 2,500rpm and because of that feels like a very powerful car even tho the peek horse power was around 60hp.

Regardless of whether you have all the cams on one shaft,or an individual cam shaft for each valve,they need to turn at 1/2 the crankshaft r.p.m. in a 4 cycle engine to stay in time.That being said,reducing valve train mass does help efficiency.It will take less spring pressure to control valvetrain motion resulting in reduced friction, and fewer total parts.

Yeah, you know that made my brain itch when I typed it, read that somewhere recently, hadn't thought about it carefully. Maybe that's what it was, the reduced mass, due to driving pairs of valves off one lobe and needing less leverage or something.

lol exactly, i was hauling around about 400 lbs of dirt + me and another adult around in my 2.2L s-10 and acceleration was no different. sure its only got like 96 HP at the wheels but it has a buttload of torque:thumbup:

chevette engine specs:(1.6L all iron everything)

bore and stroke: 3.228 x 2.980
82.0 x 75.7 mm

compression ratio: 8.5:1

net HP/@rpm: 70 @ 5200

max torque@rpm: 82 @ 2400

i belive 0-60 was in the 17 second range

"From my observations what makes these vehicles so fuel efficient? 1) Lower HP"

This shouldn't be oversimplified. For example, compare the VX and CX ('92-'95). The VX has 31% more power, and still gets 13% better mpg. Why? Because the CX was built to be cheap to buy, and the VX was built to use less gas.

The VX has a bunch of subtle tricks to boost FE, like roller cam followers to reduce engine friction.

A good technical listing of various VX FE ingredients is in this pdf.

"i own a civic VX and I have to say its not that bad."

The VX has 18% more torque (and the same weight) as the Fiat 124 Spyder I used to drive. That was considered a sports car. What's happened is that our expectations have changed. Trouble is, we can't really afford our new expectations.

I think that performance/acceleration is not really the issue. The REAL issue is WEIGHT. Someone before mentioned the Rabbit. Now the Rabbit may be considered to be a small car. BUT, this 'small car' happens to weigh a whopping 3000 pounds! 15-20 years ago, even a midsized car like a Honda Accord or Ford Taurus didn't weigh THIS much. HP is simply high because it NEEDS to be. 170HP sounds like alot for a small car. And, as anyone who has ever swapped a GSR motor into a CRX can tell you, it IS - if the small car only weighs around 2000 pounds. But a 3000 pound car needs this kind of HP just to be able to accelerate somewhat decently. The same goes for most any car out there. Although HP has skyrocketed, it has really not outpaced weight by very much over the years. And, once again, as anyone who has done a GSR swap on a CRX can tell you, mileage did not suffer as a result of the swap. This suggests that WEIGHT is a bigger problem than HP.

One more thing. Someone mentioned drag. This is another problem, ESPECIALLY with small cars (which tend to be MUCH less sleek these days than larger offerings). If you look at a 15-20 year old small car vs a new one, the new one is guaranteed to be taller and chunkier than an offering from the late 1980s or early 1990s. Perhaps the extreme example of this is the CRX, which was known for its GREAT mileage (especially in HF form). But even a VX looks sleek and aerodynamic compared to the overly tall small cars you see today. THIS is probably a big reason why small cars are just not very economical these days. And, because small cars tend to be MUCH less sleek these days than larger offerings, this is probably also a major reason why so many small cars just can't beat the fuel economy numbers of (much sleeker) midsized sedans by much of a margin these days.

The Aveo for fuel economy sucks. We had a rental Aveo for a month while our Ion was getting put back together after getting hit by a paving truck. For a car that size and a smaller motor, it should do better than that. My '06 Ion 2 manual has seen 2 tanks run to 37+ MPG. The Ion is bigger and heavier and also .6 Liters more displacement than the Aveo and yet gets better MPG.