Hot answers tagged

41

The main advantage to a lower flywheel mass on race cars is that the reduced mass allows the engine to rev more freely. The overall weight loss to the car is really not the key thing, it's letting the engine vary RPM really quickly. Being able to change RPM quickly can mean faster shifts, getting to a power band more quickly, etc, etc. It also makes the ...


37

It signifies that the car is running absolutely correct. Here is the reason why: A gasoline (petrol) molecule is made up as such: C8H18 (or 8 Carbon atoms and 18 Hydrogen atoms) Energy is obtained from the combustion of it by the conversion of a hydrocarbon to carbon dioxide and water. The combustion of octane follows this reaction: 2 C8H18 + 25 O2 → ...


28

tl;dr: They do. It's just harder to tell how much. The longer answer is that they do and that effective compression is failing you as an approximation for actual effects. Think about detonation (AKA premature ignition of the fuel-air mixture). Normally we consider two causes: compression (the change in the space enclosed by the cylinder as the piston ...


23

cdunn's answer is spot on. To add a bit (especially for cars), in a race car you often want to be dropping from something like 7000 rpm to maybe 5500 rpm (or an even higher band, depending on the engine) in a split second to make an upshift. Especially at higher engine speed, that's a lot of energy to bleed (and goes as a function of the weight of the ...


17

My knowledge of motorcycles is limited so I could be wrong, but it sounds like the clutch is slipping.


17

I agree with your praise for this car, I had one back in the day and I have never loved a car as much since. To get more from this Wankel powered beauty, it's all about two things: Getting it to breath better Replacing parts that won't take the higher RPM The good news is that the only part that needs to be replaced, is the RPM gauge sender on the face ...


12

tl;dr: No. This sort of vehicle dynamics question best addressed by Racing Car Vehicle Dynamics What follows is a basic discussion at the high school physics level. As you will see from the reference text, high school physics is insufficient to statically model the complete vehicle system. A dynamic model is required to agree with easily obtainable ...


11

The problem is, the crossfire isn't just high compression, I believe its supercharged as well. Forced induction motors like octane - the high pressure, high compression, and most importantly high combustion temperatures make you more prone to detonation. There are enough electronics in the engine (knock sensor for one) to realize that something is amiss ...


11

The flywheel keeps your engine spinning The inertia of a flywheel is in direct proportion to the mass of the flywheel. Newton's first law of motion states, "An object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force" With that in mind, motorcycle engines ...


11

Physics dictates that rotational inertia impedes acceleration... which is why a lighter flywheel is considered to be a performance mod Less rotating mass = more acceleration, if all else is equal But rotational inertia helps an engine idle stably which explains why manufacturers don't go for lighter flywheels from the get-go If they opt for a lighter ...


10

Firstly, the comments made by others are correct. The power used by each of the components listed will vary on a component by component basis and even on an installation by installation basis. The power used by each component will also vary depending on the speed that it is running at. Also the number and type of components will vary from car to car. With ...


10

A six pack usually refers to the Chrysler (Mopar) carburetor setup which is three-two barrel carbs on an intake. You'll most often hear of it as a 440 Six Pack, the 440 referring to the Big Block Mopar engine displacing 440 cubic inches. Here is an image of such a setup: The interesting thing about these is they are setup sequentially, where the main ...


8

Gasoline is made in large batches. Each batch has a number of attributes that should be met; Octane, specific chemistry, volatility, contaminates, ethanol content, and others. The output is dependent on the crude that went into the refinery and the processes the refiner has at hand to process it. Refineries vary in there capabilities. There are over 60 ...


8

NOTE: The following example assumes output in lb-ft & horsepower. Dynamometers can also measure torque output in Newton Meters or Kilowatts just as easily, or any other measure of torque and power, for that matter. First off, let's get everyone on the same sheet of music. When it comes to vehicles, there are two basic types of dynamometers: engine & ...


8

bit of a braindump... Hard to get more specific without more specific requirements... Is this a drag car, track car, street car, daily driver, etc. Basically this will lead you to - where do you need power and how much do you need. "Speed costs money, how fast do you want to go?" Just about everything is a balance of top end power vs bottom end power. ...


8

Just like with any other internal combustion engine, there are two ways to increase power output: add more cubic inches of displacement; make the motor think it has a larger displacement. More Displacement The rotary engine (Wankel) is a different breed. You cannot just bore/stroke the engine like with other piston based engines, so you have to go a ...


7

What does it do? (better performance [and how so?]? better mileage? cooler sounds?) It depends. One of the goals of a performance exhaust is usually to create a tuned system: A tuned exhaust system is an exhaust system for an internal combustion engine which improves its efficiency by using precise geometry to reflect the pressure waves from ...


7

Torque is how strong your engine is and Horsepower is a measure of how fast it can use that power. That is why a Diesel engine with 400Nm of Torque cannot out-accellerate a petrol car with 400Nm of Torque. Horsepower is calculated by multiplying the amount of torque by the RPM of the engine (and dividing by 5,252. But that's not important here). Because a ...


7

You have a lot of big questions here, so will try to answer them for you, but be ready for the diatribe of the century ;-) There is a simple rule when talking about power/torque output which goes: There is no replacement for displacement. If you increase the size of the four cylinder (through whatever method) to match the size of the six cylinder, you will ...


7

The short answer is no. The engine is most efficient at the RPM when maximum torque is achieved. It's easiest to explain with a picture. Power is a function of torque and RPM. Maximum torque is achieved because the engine is able to move the maximum amount of air and fuel in and out of the engine. The power continues to climb even when the torque starts ...


7

Generally, in the automotive world, there are two different types of dynamometer (or dyno for short) which might be used: chassis dyno; engine dyno. I'll discuss the general procedures for each type of dyno. Every dyno operator has their own procedure and will operate it how they see fit. You have to allow for this mainly because it's their dyno, they paid ...


7

A cam... in its most generic sense converts rotary motion into linear motion or vice versa using solid egg-shaped actuators (lobes)¹. An engine camshaft... refers to the shaft which houses a series of cams that actuate the opening/closing of the intake and exhaust valves on a four-stroke engine. A performance camshaft... is just a camshaft whose ...


7

This question and answer from @BobCross is very illuminating and may help you in your decision making process. Have a look.


7

One thing which hasn't been mentioned here about why a lightweight flywheel may not necessarily be a good thing for the street is, just like brakes, the rotational mass of a regular weight flywheel will allow for better heat control which is caused by engaging/disengaging the clutch during normal operation. The mass of a regular flywheel will be more ...


6

Every gallon of fuel your vehicle burns produces a gallon of water out of the exhaust. If the weather is cold you will see it as steam. If the rear of the exhaust system is still cold even in warm weather it will be for a short time after start-up, you will see the drips. On a hot engine/exhaust you will not see any drips from the tail-pipe. If there are ...


6

Engine Remap One way of increasing the power from your engine, depending on the car is to get your engine "remapped". This effectively means that your cars on-board computer (or ECU) has had its software changed and as a result the engine is told to produce more power. It should also be noted that changing the software used by the car can also be referred ...


6

Mow much money do you have? :D In all seriousness: Swap in a later 13B engine and give it a fresh rebuild. Install a Racing Beat header and exhaust system. The Racing Beat intake is also pretty good. Mind you, this is setup for the upper rev range. Put a good carburetor on it, like a Holley 600 (mechanical secondaries). Do not remove the belt driven fan! ...


5

... I'm curious about if such fuel is safe to use in your typical stock engine on a passenger car If they've added lead, no. I suspect that it's very unlikely that anyone is selling leaded gas at a common access pump (at the race track, maybe). If no lead, then it's quite likely fine but a waste of money for most cars and drivers. Cars (especially ...


5

this sounds just like a clogged fuel filter to me. The car starts fine because the fuel has had time to percolate through the clogged filter but once that fuel is used up the engine starts starving for fuel because the flow through the filter is not great enough to run normally. Since it occurs randomly it will be hard to test this. But I would try ...


5

Reading around a bit on the dual mass clutch the friction plate between the two masses is the component that will often wear out as it is designed to keep from too much torque being sent through to the transmission, taking the hit itself instead (choice between burning up a couple hundred dollar flywheel or a transmission in the thousands of dollars). ...



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