dalaw

Not sure if the rotary is entirely efficient since its fuel economy is pretty bad.

nookiemonster

^^^ True, but maintenance is so low, particularly on NA rotaries, that it pretty much balances out...well almost I suppose.

I get about the same gas mileage as my friend's G35 coupe. Sports cars aren't known for fuel economy anyways, and if that's a deciding factor for you, then you shouldn't be buying one.

dalaw

haha, sorry i forgot that you have a rx-8, i shouldnt be saying bad things about the rotary.

nookiemonster

Hahah no it's all good. I know the goods and bads of the rotary, and to be honest the RX-8 kinda frustrates me with fuel economy sometimes, but I need to quit pushing the pedal so close to the floor

I'm open to subjective criticism...we all know that every car has strong and weak points so eh...

Metallica454

iTrader: (1)

Effeciency isnt only based on fuel mileage. Simple design, low maintencance, with good hp numbers. The smoothness of these engines are also exemplary. A rotating mass is so much smother than 4-8 pistons bouncing up and down violently.

Drakkar

well i just stated a fact about the sohc design i didn't say that that they were the best design for high rpm's i said that they were capable

S2000man01

iTrader: (1)

oh i was under the wrong impression there

Mirage

iTrader: (4)

WRONG! WRONG! WRONG!

Here is the truth about DOHC & VTEC!
(It must be true, I found it on the internet!)


"SOHC and DOHC stand for Single or Dual Over Head Cams. A SOHC makes it harder for the engine to reach higher revolutions per minute, or RPM's since it only has one cam. A DOHC gets twice the compression because both cams work together on the upstroke and down stroke. DOHC is generally better because it lowers the tension needed to reach the higher RPMs since it pulls and pushes from both sides. RPM is another term used often. RPMs tell the driver the amount of time it takes the engine to complete its four stroke combustion* and is usually located on the left side of the odometer. The higher the RPMs can go without the needle in the red zone, the faster you go more quickly. This is called redlining. When the engine starts to redline, it's telling the driver that parts may begin to bend, stretch or break, so slow down. Hence the red color; red was intended to give the notion of danger, or stop. The higher the RPM, the better air flows through the engine; the better the air flows the engine, the better compression you get, which in turn, builds up more horsepower. VTEC is Variation valve Timing and lift Electronic Control. At a certain amount of RPMs, VTEC kicks in and makes the car speed up a little."

usafstud

iTrader: (2)

from my experience, rotaries are horrible in reliability.

the seals will eventually crap out. many people, two i know, have got their rotaries on fire

btw, my friend worked on must of the rotaries at XS Engineering

Metallica454

iTrader: (1)

Holy crap dude, I have never seen anyone so far of the truth.

S2000man01

iTrader: (1)

holy crap that article is so off it's not even funny. let's begin here. i assume you posted it cuz it was so wrong it's funny. lol
kind of yes. but he doesn't explain why.
wow. compression has nothing to do with how many cams a car has. compression is this: volume of open space in combustion chamber at BDC / volume of open space in combustion chamber at TDC. oh, and one cam does intake valves, the other does exhaust valves. he's on crack with the whole upstroke/downstroke thing.
uh.... what?
i couldn't even make up something this retarded.

did a 3rd grader write this? lol. seriously where did you find this post?

Drakkar

well v tec really doesn't "kick in" it just opens another exhast valve that makes it so the engine breathe better, this also makes the engine sound "louder" but other than that and what everyone else said ur good. lol

dalaw

WTF?

RPM = revolution per minute, nuff said.

nookiemonster

Apex and corner seals wear out on 13B-T and 13B-REW engines. You can thank the turbos for this. Pistons and rotaries, all the same, wear out sooner in a FI application.

Rotaries, particularly run very hot. With a turbo, it's even hotter, so you burn off the seals and lose compression. However, in a NA application, rotaries have been known to last over 200,000 miles without a rebuild. Everyone pays attention to the turbo cars, and of course the turbo cars are higher maintenance. Particularly, the sequential twin turbo FD3S. Imagine how hot a turbo would get, when it's being spooled by another turbo, and everything mounted onto a 1.3L rotary engine. Imagine the heat from that setup. These are the cars, yes FD's, that are VERY VERY high maintenance.

My father had an NA FC3S before he bought his FD3S. This particular car was sold to my uncle who still drives it even now. It has over 140K miles with no rebuild. The Renesis is expected to far exceed the NA rotaries of the past.

bgoetz

iTrader: (1)

wrong intake valve on SOHC and both the Exhaust and intake valves on DOHC

S2000man01

iTrader: (1)

you're thinking vtec-e. vtec-e closes an exhaust valve at lower rpm for better fuel efficiency and emissions, and opens the valve up at higher rpm for more power.

regular vtec on a dohc car when it "kicks in" actually is increasing the lift, timing, and duration of the valves on both the intake and exhaust side. and in fact, the intake valves start opening before the exhaust valves are completely closed.

on a sohc vtec, it only changes the lift and duration on the intake side.

again, vtec-e closes an exhaust valve at lower rpm.

and 3 stage vtec, which combines the vtec-e, and the sohc vtec.

jakejham

i heard you have to check the oil after every other fill up or something on the FD. is this bs? or is this pertaining to the loss of compression as well

Mirage

iTrader: (4)

I already told you where I found it, the Internet!

This article is Exhibit A in the case against trusting anything you read on the web.

For your enjoyment, I will post the entire text, but first get some aspirin and maybe a stiff drink because you're going to need them after reading this:

************************************************** *******

Domestic or Import:
Is it really a debate?
By Alexis Carmicheal

The domestic/import debate has been plaguing the car scene for years. Care enthusiasts around the world are in constant arguments about which category has the best or fastest cars. Before the argument is discussed, there will be a few terms of frequent use. Horsepower and torque are just the first of many. Horsepower is a determinant of how fast a car's engine can really be. The higher the horsepower, the faster the vehicle will go. Torque is the total amount of pounds that the engine puts on the wheels. SOHC and DOHC stand for Single or Dual Over Head Cams. A SOHC makes it harder for the engine to reach higher revolutions per minute, or RPM's since it only has one cam. A DOHC gets twice the compression because both cams work together on the upstroke and down stroke. DOHC is generally better because it lowers the tension needed to reach the higher RPMs since it pulls and pushes from both sides. RPM is another term used often. RPMs tell the driver the amount of time it takes the engine to complete its four stroke combustion* and is usually located on the left side of the odometer. The higher the RPMs can go without the needle in the red zone, the faster you go more quickly. This is called redlining. When the engine starts to redline, it's telling the driver that parts may begin to bend, stretch or break, so slow down. Hence the red color; red was intended to give the notion of danger, or stop. The higher the RPM, the better air flows through the engine; the better the air flows the engine, the better compression you get, which in turn, builds up more horsepower. VTEC is Variation valve Timing and lift Electronic Control. At a certain amount of RPMs, VTEC kicks in and makes the car speed up a little.

In general, import cars rule the scene in the matter of speed. They offer more of a variety when it comes to choosing the vehicle. Domestics have less of a variety. Ford is the dominant domestic, while Honda, Acura, Nissan, and Mitsubishi are among the imports; however, who is to say one is better over the other? Do these import cars have better gas mileage? Is it true that imports are more fuel efficient and economical? Some say domestic are just better quality. Both have merit and individual good qualities. This paper will investigate both domestics and imports and determine which is more appropriate for what demographic. The comparison will include the main players of each side. The end result will be informative, if not amusing.

Foreign vehicles, also known as imports, are as enjoyable as any other car on the market. What makes these cars so enjoyable? Well for starters, many of them are compact, as in tiny, and easy to drive. Handling is usually good due to the smaller size. Some take corners as if the vehicle were on rails. The warranties are often better and more thorough. The engine type varies, body styles can be altered to the consumer's liking, and they are priced reasonably cheap. Gas mileage is better, and a full tank of gas that costs less than ten dollars tends to make customers happy. The engines in foreign cars are generally smaller and faster than that of domestics. It is even rumored that Ford had to ask Honda for help when designing the Focus engine. A major manufacturer of foreign cars, is Honda. Honda also makes Acura, but Acura is simply another company created when Honda came to America. Acura does not exist in Japan. Keep in mind, these are imported cars, they just have manufacturers and dealerships in America, as an extension. The cars of Honda generally have a good Consumer Report rating. According to Consumer Report, customers of Honda are on average quite satisfied, as are Acura owners. Nissan and Volkswagen have been participants also, but not as popular with the public. As of 2002, Nissan and Volkswagen will be releasing their fury into the market soon. Let's examine some of the most popular cars of Honda: the Civic and the Acura Integra. These two have the same framework for the body, just a different exterior. These two come in two and four door varieties with the base models starting at $23,995 and go up or down, depending on the consumer and the region. These cars come in automatic and manual transmission, with the faster models being available only in manual transmissions. Both base models have about 110-120 horsepower.

The Honda Civic currently has many versions: DX, EX, HX, LX, and SI. The Civic has generally 120 horsepower and comes with good safety ratings. It is a car that parents might purchase for a sixteen year old because of the ratings and reasonable price. However, a Civic is the easiest car to modify and make faster. The SI is the one with the most horsepower of the five. The 2002 Civic SI will carry a high output 2.0-liter, DOHC four-cylinder engine. This i-VTEC ("i" for intelligent) power plant produces 160 horsepower and 132 pounds of torque-the most ever for a Civic. The base model Integra is right up there with the Civic: same frame, different body style. Three 1.8-liter DOHC four cylinder engines are available. A 140 horsepower version goes into the LS and GS coupes. The GS-R gets a 170-hp variant, which uses Honda's variable valve timing and lift electronic control (VTEC) technology, borrowed from the high dollar NSX sports car. In the Type R coupe, the four-cylinder VTEC engine is rated 195 hp at a rapid 8,000 rpm. In the Type R, modifications have already been made to engine so that the owner does not have to. It is quick. The price tag of the Integra ranges from $19,000 to $30,000 depending on the dealer and the make of the car. The Type R will have a higher price due to the modifications already performed on the car.

American made cars, also known as domestics, have a loyal fan base. On average domestic cars are cheaper. The general opinion of the public was that domestics use much more gas when being pushed more and therefore, more expensive to maintain. The Ford Mustang has a past and a future. The Mustang has made a name for itself in the automotive industry. Ford has always had success with this car unlike some of the events in the past few years. Mustangs are also available in numerous variations: the Mustang LX, the Mustang GT, the Mustang Cobra, and the Saleen Cobra. The Mustang Coupe has a standard 3.8 Liter V6 engine with 190 horsepower at the wheels. The Mustang GT has a 4.6 Liter V8 with 260 horsepower at the wheels. The Cobra has 320 horsepower in a V8 engine. The Mustang is Ford's counterpart to the Civic, only it offers a lot more power. The GT starts at $17,820 and the Cobra starts at $23,360. The Cobra is limited and rare, as is the Saleen, since Ford produces only so many every year. The after market for the Mustang is limited, although they are probably fast enough as it is. Mustangs are good for people who desire speed at a low price.

The Ford Focus is another way Ford is tryin g to keep up with the times. Miscellaneous reviews rave that it stops with authority, responds without hesitation, and, with the upgrade 2-liter Zetec engine, delivers enough punch to stay close to the leaders of this pack, notably the Honda Civic EX, and the Acura Integra. The Focus price range, including destination charges, opens at $12,280 for a basic ZX3 hatchback. In 2002, Ford will release the SVT Focus, which has 170 horsepower and redlines at 7,200 RPMs. This is a highly anticipated newcomer simply because the base model Focus was a bit slow, and left enthusiasts hungry for power.

All in all, which car is purchased all depends on what the consumer wants and needs. Different companies offer better warranties and certain companies claim to have better drive train. Over the years, the public had formed a general opinion of which cars were better. Foreign cars seemed to have an edge over American made muscle cars. Besides guzzling gas and having numerous defects, Americans became sick of muscle cars and all their glory. After turning to imports, customers realized that imports required just as much care as domestic. Both imports and domestics still have their loyal fans. There will always be Ford fans and their will always be the import fans. So which one is better? Who knows. Once again, the consumer decides what he wants. As of right now, imports dominate the market, and the after market. It all depends on the wants and needs of the future vehicle owner.

*The process of an RPM works like this: Air goes into the intake. As the cam opens, and the as the piston is going down, it will fill the cylinder with a combination of gas and air. The valve then closes, then the spark plug fires, and the gases inside the cylinder explode. The piston starts coming back up and compresses the gases, turning the crank causing the exhaust valves to open and release the gases to the exhaust manifold. This is one RPM. For the slower readers, engines basically go through 4 strokes: suck (the intake of air), squish (the compression), bang (the spark plug igniting the gases), and blow (gases out the exhaust).

************************************************** *******

nookiemonster

Damn...can we get cliff's notes?

ravolutionazx

are we writing essays today?

Mirage

iTrader: (4)

You don't want cliff's notes, you want to read the whole thing. It's priceless.

S2000man01

iTrader: (1)

i am now dumber after having read that article. is there someplace i can comment or is it on a forum or what? i need to un-dumb myself and purge that crap from my brain.

S2000man01

iTrader: (1)

what's really sad is this was probably some kid's research paper from the sound of it.

i'd have given him an F and sent him back to the 4th grade.

S2000man01

iTrader: (1)

highlights, and cliff notes
aside from my previous quote:

he had to look up determinant
huh... i thought the car's curb weight would have had something to do with how many pounds are put on the wheels. who knew?
.... not really.
huh... that's a new one
lol ok
the only imports i know of that you can fill the tank for less than 10 bucks are the 2-wheeled kind.
the engines are faster? i guess technically that's right. i mean an S2000 engine spinning at 9000rpm is technically spinning faster than a corvette's at 5500rpm right?
sure. and al gore pioneered the internet.
actually some hondas like the civic and accord have more american parts in them than some fords
their fury? does that mean nissans and VW's will have laser guided mounted surface to surface missiles to "eliminate" the competition?
.... hmmm. chassis codes are your friend.
how much crack do you have to smoke in order to get that effect?

people get sick of glory?
cams open? and the piston comes back up before the spark ignites my retarded friend, and it compresses it BEFORE it fires also. lol. i also didnt know the crank causes the exhaust valves to open.
2 points of irony here. 1, the phrase here which he pasted form howstuffworks.com contradicts the order of events he just explained previously, which were apprently for the non-slow readers.
2, he actually said "for the slow readers" when he himself is probably the tortoise of them all.

Metallica454

iTrader: (1)

The Mustang is Ford's counterpart to the Civic, only it offers a lot more power. The GT starts at $17,820 and the Cobra starts at $23,360.

OMFG!!!!! Mustang is Ford's counterpart to the Civic? Then what is the Focus? If a Cobra started at $23K, I'd be all over it!

I would like to know who wrote that. Someone needs to walk up to him, slap his face and say, "No, no, bad ricer."

82801BA

Another advantage of SOHC....
Comparing rpm by rpm, SOHC makes more power and torque at low and mid rpm all the way to the maximum power of SOHC.

I've seen my friend's Si making 86hp at 5000rpm, while mine runs at 105 at that point already...

Is this why some ppl mod the car and beat the Si?

UTICivic

iTrader: (3)

hehe

S2000man01

iTrader: (1)

huh? your post doesn't make sense.

I assume you meant an advantage of DOHC? rpm for rpm, a dohc will make more power all the way if you set the engine up the same way for argument's sake.

82801BA

No, in reality, DOHC engine makes less output than SOHC engine.
Think, in general, better compare it with non-VTEC for fairness.....

A SOHC F22A4 Accord engine makes 130hp at 5200rpm, while a F22B Prelude engine makes 160hp at 6000rpm. It has a 30hp difference across 800rpm. But also take into account that F22B has intake air bypass(which helps top end with shorter intake runner. In an Accord engine, that means 10hp) while F22A4 doesn't.

In term of VTEC, we have D16Y8 SOHC engine with 127hp at 6600rpm and B16A2 Si engine for 160hp at 7600rpm. Majority of power of B16A comes above 4800rpm. But most Si are around 140 at the wheel and most D16Y are making 110. However, D16Y has a more flattened curve than the Si anyway. So rpm to rpm, stock to stock, SOHC engines makes more power at any specific rpm, up to where the maximum power is set at.

I just found an Si dyno with only 82whp at 5000rpm, can't believe that. I have my EX peak set at 5300rpm for 117whp. And SOHC engine also has weight/inertia advantage over DOHC. A SOHC engine breath better(I really don't know why, but I've heard a lot about it) at low rpm therefore also generates higher torque than DOHC engine at the same range.

S2000man01

iTrader: (1)

everything you are saying simply doesn't make sense.

you're comparing apples to oranges. if you could compare 2 of the exact same engine, one being a dohc, the other being an sohc, the dohc will make more power at any given rpm. why? because the dohc can be far better tuned for optimum efficiency, due to the fact that a seperate cam runs the intake valves, and another the exhaust valves.

and, looking at a stock dyno chart for both the D16y and the B16a, they have almost the exact same torque curve both starting at about 80lb/ft around 2500rpm until just around 5000rpm, when the B16 jumps far above the D16.

and where did you hear that an sohc engine breathes better? lol. that's just simply untrue.

everything you're trying to tell us the exact opposite of what gives a dohc an advantage in the first place.


SI dyno (note the stock torque curve)



http://www.importtuner.com/tech/0403it_edelbrock/#
D16y dyno (and this is with an aftermarket throttle body)