I am new, and I got questions

[Auto_newb]

Ok here's the thing, I only recently got into cars (I used to be a gun freak, but meh, I gotta take a break from all that). If you guys can help me, I got a load of questions to ask:

1. What does final drive ratio mean?

2. What are street dampers?

3. If FR means front engine, rear drive, then MR means middle engine, isn't that where the seats are?

4. What's a double wishbone suspension?

5. What's a carburetor do? What's it look like?

6. How does a carburetor differ from fuel injection systems?

7. Why do I always see people with those fat exhaust tips? What's so great about it? Does it increase performance?

More coming soon ....

[ales]

1. What does final drive ratio mean?

There is a gearset in a car's differential. The ration of those gears is the final drive ration.

2. What are street dampers?

Shock absorbers (aka dampers) that are comfortable to use on the streets, in everyday traffic? Race shocks are firmer and don't offer as comfortable a ride as with softer shocks, but they do offer noticeable performance advantages.

3. If FR means front engine, rear drive, then MR means middle engine, isn't that where the seats are?

Well, you don't see rear seats in a mid-engined car.

4. What's a double wishbone suspension?

One of the types of suspension. Basically, two horisontal A-arms on each side. Most race cars have those, and in open wheel series you can see them easily - F1/CART/IRL, etc.

5. What's a carburetor do? What's it look like?

It provides fuel and air to the engine (and mixes them at a precise ratio). Use google picture search engine to find a picture.

6. How does a carburetor differ from fuel injection systems?

Carburetors are mechanical while injectors are electronic.

7. Why do I always see people with those fat exhaust tips? What's so great about it? Does it increase performance?

For looks. The tip itself adds no performance advantage. Usually the whole exhaust is made bigger to present less restrictions to the airflow, or rather exhaust gas flow, from the engine.

[Neutrino]

Originally Posted by ales

1. What does final drive ratio mean?
6. How does a carburetor differ from fuel injection systems?

Carburetors are mechanical while injectors are electronic.

small correction here since the early fuel injection systems used mechanical injectors

[SaabJohan]

Carburetors use a venturi, this will accelerate the air and cause the pressure to decrease. This will suck the fuel in (often assisted by a pump) and vaporise it, at least partly.

A fuel injection system will use injectors to inject the fuel. Usually there is one injector per cylinder, they can be placed in the combustion chamber, intakerunners or the intake manifold. The amount of fuel going to be injected is "calculated" mechanicly or electronicly so it's going to match the airmass the engine will consume.

Rear double wishbone suspension from a Sauber F1 car. The carbon fibre wishbones are fitted to the gearbox, the shockabsorbers are activated by pushrods:

http://www.bubeck-modellbau.de/image...u_bild3_gr.jpg

[Auto_newb]

The black things are the double wishbone suspension right? What is this design that makes it so great?

Sorry I still don't know what you mean about the final drive ratio

Thank you all for the answers, I read every word!

[454Casull]

MR does mean an engine between the two axles (or between the rear axle and the front spindles, if you will). The engine is situated behind the driver.

People get fat exhaust tips because they look better than stock, make louder noises, or are generally stupid.

A double-wishbone suspension setup is advantageous because the suspension accurately locates wheels on bumps, body roll, squat, etc.

Final drive ratio is the ratio between the final gear (a big ring gear in the differential) and the last gear in the gearbox, IIRC.

[Auto_newb]

Does fuel injection maximize the car's performance while still using the least amount of fuel?

How does nitrous oxide allow more oxygen to be crammed inside a cylinder?

Does the fuel injection happen JUST before the intake valve?

How does a car burn oil? (I don't really understand this )

What do the letters and numbers on the tire mean? (I forgot about this one)

What's a head gasket and what's it do?

[Sluttypatton]

1) Yes, fuel injection is capable of mixing fuel far more precisely than any carburetor. I say "capable of", because there are some horrible fuel injection systems out there that wouldn't match up with a good carburetor. But in general, fuel injection will maximize power, while minimizing fuel consumption.

2) Read this

3) Not always but yes, it is a common myth that fuel is injected directly into the cylinder...this is untrue. Fuel can be injected at various points, the ideal place is pointing directly at the back of the intake valve. Another system known as "throttle body injection", has fuel injectors built into the throttle body, so that fuel is injected before the manifold. The problem with this is that different amounts of fuel can reach different cylinders, making it somewhat less precise (defeating the whole purpose of fuel injection...precision). The type that uses multiple injectors, usually aimed at the intake valve is known as "multi-port fuel injection", and is superior to "TBI".

4) Cars are not meant to burn oil, and have mechanisms to stop them from doing so. The pistons have oil control rings to keep oil from entering the combustion chamber, and the valves have seals to keep oil from getting in that way as well. However, nothing is perfect and even new motors allow small amounts of oil into the combustion chamber, where it is burned along with the fuel. As engines get older, these mechanisms begin to deteriorate, and allow greater amounts of oil to enter the combustion chamber, leading to the blue smoke you see coming from the tailpipes of older vehicles.

5) I will use my tires "numbers" for an example. My tires are 205/40/R17:
the 205 is the treadwidth in millimeters, the 40 is the "series", "profile", or "aspect ratio" of the tire, and tells us how tall the sidewalls are. The aspect ratio is a percentage of the treadwidth, meaning if you wanted to know how tall my sidewalls are you could find out this way; (.4*205=82), my sidewalls are 82 millimeters tall. The R means that the tires are of radial construction (rather than bi-ply), and the 17 means that the tire is meant of 17 inch wheels.

6) The head gasket creates a seal between the cylinder head and the block. This prevents coolant from spilling into the combustion chambers, oil from contaminating the coolant (or vice versa), and maintains compression in the cylinders. In order for a motor to run it needs four things; fuel, oxygen, compression, and spark. Without a head gasket, the cylinders would leak compression and the motor would either run very poorly, or not at all.

And to clarify a final drive ratio, the transmission is simply a unit consisting of a number of gear ratios, after the transmission, the power goes through a differential, which is a last set of gears, with the purpose of sending the power to the wheels. The ratio of the big gear to the little gear in the differential is the final drive ratio (because it is the "final" gear ratio in the "drive"line). So if a car has a final drive ratio of 4.09 (the UK Kas with power steering do) it means that the final gear set that the power goes through before hitting the wheels has 4.09 teeth on the big gear to every 1 tooth on the small gear. I hope that clears some things up.

[ales]

3) Not a myth. While this is not widely used, some engines do indeed have the fuel injected directly into the combustion chamber, e.g Mitsubishi GDI (Gasoline Direct Injection) engines

[Sluttypatton]

Yeah, I had heard of that, but last I heard it was still under development. So I opted to keep it simple as to not overload him and just confuse him. Almost no motors use direct injection, and none of the few that do, are on the road as daily drivers. I think, for now, direct injection is purely in the research stages.

[Sluttypatton]

Sorry, I was wrong about them not being used in road cars. Apparently they are used in Galants, and Legnums?. I stand corrected.

[Neutrino]

Originally Posted by Sluttypatton

3) Not always but yes, it is a common myth that fuel is injected directly into the cylinder...this is untrue. Fuel can be injected at various points, the ideal place is pointing directly at the back of the intake valve. Another system known as "throttle body injection", has fuel injectors built into the throttle body, so that fuel is injected before the manifold. The problem with this is that different amounts of fuel can reach different cylinders, making it somewhat less precise (defeating the whole purpose of fuel injection...precision). The type that uses multiple injectors, usually aimed at the intake valve is known as "multi-port fuel injection", and is superior to "TBI".

you are corect except for one car...the new bmw 7 series with direct injection were fuel is injected straight in the cylinders instead of the intake manifold

http://www.bmwusa.com/

go to that lonk then to 7 series and then chose 7 technology for more details

[Sluttypatton]

You learn something new every day, thanks for the info.

[SaabJohan]

Fuel injection directly into the cylinders was first indroduced by Mitsubishi, this is a couple of years ago. I know that Volvo also used that Mitsubishi engine, but it must have been at least five years ago that engine was introduced, and even earlier in Mitsubishi cars.

Audi is also using direct injection in their LeMans racer since it gives a better fuel economy. But if we look at an F1 engine they have the injectors placed in the plenum, one for each intake since that gives the best air-fuel blending.

Ferrari F1 engine:
http://www.alfapower.nu/albums/album58/acq.jpg
http://www.alfapower.nu/albums/album58/abx.jpg

Audi LeMans engine:
http://www.mulsannescorner.com/Audi-SP2.jpg

[Neutrino]

ok this might sound stupid but what about having the injectors push in both fuel and air like in the case of direct port nitrous were they inject both nitrous and fuel

and if you can combine this with direct injection you would not even need intake valves