15 votes
Accepted

Why nitrogen and not carbon dioxide is used in critical tire applications?

Nitrogen is inert and doesn't affect rubber or the steel rim. Carbon dioxide is highly reactive and affects both the rubber by causing swelling in the rubber. It also would cause corrosion in iron ...
Old_Fossil's user avatar
  • 3,962
15 votes

Why is it that when supercharging, it's preferred to compress the input, rather than pull a vacuum on the exhaust?

The power of an engine is not determined by the difference in pressure between the combustion chamber and the exhaust. Power is determined by how much energy one can put into the combustion chamber ...
fred_dot_u's user avatar
  • 4,465
13 votes

Should the inflation pressure for low profile tires be the same as for regular tires?

In almost all circumstances you should use the manufacturer's numbers as your guide. They are aware of the requirements of their wheels, and they do understand that a low profile requires a certain ...
Rory Alsop's user avatar
  • 18.6k
13 votes

Tire pressure with load and heat

As long as you are running Light Truck (LT) tires, you should be just fine. Manufacturers take into account the tire pressure is going to go up due to heat buildup. This is why you check tire ...
Pᴀᴜʟsᴛᴇʀ2's user avatar
13 votes

Why is it that when supercharging, it's preferred to compress the input, rather than pull a vacuum on the exhaust?

OP's question states: It should follow that turbocharging should be equally effective pumping air out the exhaust, than in the inlet. No, it is not as effective. You can't reduce the pressure to ...
Weather Vane's user avatar
  • 2,189
12 votes

Why nitrogen and not carbon dioxide is used in critical tire applications?

Nitrogen makes up around 80% of Air - therefore its more readily reclaimed and separated than the smaller amounts of other gases in air. I.e. the process for reclaiming nitrogen from air could be ...
Mauro's user avatar
  • 2,655
10 votes

Difference between fuel pressure and fuel rail pressure

On a car with fuel injection there can be two fuel pumps, one high-pressure and one low-pressure. The low-pressure pump moves the gas from the tank up to the high pressure pump. The high pressure ...
Ukko's user avatar
  • 885
9 votes

Direct Injection Injectors - How do they prevent blow back into the fuel system?

In cylinder pressure is in the 200 psi range. GDI fuel pressure is varied from 500 up to around 3000 psi. This alone is enough to keep fuel blow-back to a minimum. Carefully engineered injector pintle ...
Fred Wilson's user avatar
  • 11.6k
9 votes
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Direct Injection Injectors - How do they prevent blow back into the fuel system?

I will try to answer this as best as possible. There are a few factors that come into play here (Mainly the manufacturer of said engine). Direct injection petrol engines work much like a diesel. You ...
cloudnyn3's user avatar
  • 3,333
9 votes
Accepted

Why is it that when supercharging, it's preferred to compress the input, rather than pull a vacuum on the exhaust?

IMO this is not a stupid idea, however it doesn't actually make sense for multiple reasons: A naturally-aspirated Otto or Diesel engine by itself doesn't expand the gas even to atmospheric pressure. ...
leftaroundabout's user avatar
8 votes
Accepted

Should the inflation pressure for low profile tires be the same as for regular tires?

tl;dr: it depends. Usually bigger wheels + thinner tires = higher pressure. So, should one keep the pressure to what's recommended by the manufacturer regardless of the tire dimensions? Sort of. ...
Bob Cross's user avatar
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8 votes

Does free revving a diesel engine to 4000 rpm (1.6 crdi- hyundai) cause any damage?

Short answer - no. It's perfectly okay. And , it's also perfectly okay to be annoyed. It's one of those things mechanics like to do (no offence to anyone). Similar to endlessly hitting refresh on a ...
chilljeet's user avatar
  • 2,196
8 votes
Accepted

Why does a tire have the same air pressure when mounted on the car and when not?

The very short answer is this: for a gas at constant temperature, the product of pressure and volume is constant. This is the ideal gas law - close enough for this purpose. When you load a tire, it ...
Floris's user avatar
  • 206
7 votes
Accepted

Does high air pressure throw off wheel balance?

No. Balance is caused by even weight distributed around a tire. If there is more weight in one spot the tire will "wobble" when spun. Inflating a tire more may alter the diameter, but the weight of ...
Sir Swears-a-lot's user avatar
6 votes

Showing Oil Pressure When Engine Cold and Not Running

You could be correct with a bad sensor, or possibly, a corroded connection (vibration making the contact) or a broken wire or a faulty contact in the ignition switch. That's the fun (!!) with ...
Solar Mike's user avatar
  • 34.6k
6 votes

Why is it that when supercharging, it's preferred to compress the input, rather than pull a vacuum on the exhaust?

There is no direct path from the intake to the exhaust, at least one set of valves will be closed at all times. The exhaust valves open and the piston pushes the exhaust out of the cylinder, then the ...
GdD's user avatar
  • 16.9k
5 votes

Showing Oil Pressure When Engine Cold and Not Running

When you start most vehicles and motorcycles are not an exception to this, all of the display lights are lit indicate that they are all working. If something is not "ON" then it's very possible that ...
Rowan Hawkins's user avatar
5 votes

When does the spark plug ignite the air fuel mixture?

The power stroke (the bang in the series: Suck; Squeeze; Bang; Blow) begins after top dead center (TDC) past the compression (Squeeze) stroke. The spark does ignite the air/fuel mixture prior to the ...
Pᴀᴜʟsᴛᴇʀ2's user avatar
4 votes

Tire showing low pressure after few KMs of ride

I think you have pressure loss on your bead, pressure sensor or Schrader valve Regardless of the tire holding N2 or straight atmospheric gasses, all of the same principles apply to pressure loss. ...
DucatiKiller's user avatar
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4 votes
Accepted

Fuel Rail Pressure dropping & engine shutting down - Whats the cause?

If the fuel rail pressure is dropping then either something is obstructing fuel flow intermittently, or your fuel pump is having issues. I'd start with the cheaper things to look at: Fuel cap: As ...
GdD's user avatar
  • 16.9k
3 votes
Accepted

Diesel, fuel pressure drops at speed

The volume regulator at the high pressure pump would surely be a good candidate for the mentioned symptoms. Normally the volume regulator seems normal when accelerating (because he is mostly open, so ...
Martin's user avatar
  • 8,448
3 votes

What pressure should i run in my winter rally tyres?

Generally speaking, reducing the pressure will be a dangerous idea - underinflated tyres don't stop anywhere near as well, and steering will be more of an issue. It's actually supposed to be quite a ...
Rory Alsop's user avatar
  • 18.6k
3 votes

Low-side and high-side pressures lower than expected after AC repair

Your car AC is perfect according to you, except one thing that you have mentioned!! "The compressor clutch cycles about 12 seconds on, and 12 seconds off. (I'm not sure what's an exceptable ...
user30612's user avatar
  • 257
3 votes

Low-side and high-side pressures lower than expected after AC repair

@RyanV.Bissell I am impressed with how much attention you gave to this task. Last year, I took my VW to authorized dealer to replace the compressor and they overfilled it. After that, they did not ...
Evren Yurtesen's user avatar
3 votes
Accepted

Tyre Valve Pin Too Far In

You could buy a similar length new valve stem (about $1), and swap out the cores to see if that helps the situation. If it doesn't, you'll have to get the valve stem replaced. Quality control on ...
SteveRacer's user avatar
  • 12.4k
3 votes

Tire pressure with tires on vs off the car

The air pressure in tires are affected by temperature, which is why one measures and adds air when the tires are cold, undriven. When inflated, the shape of the tire will change slightly, as it ...
fred_dot_u's user avatar
  • 4,465
3 votes

Does high air pressure throw off wheel balance?

It won't affect wheel balance, but high tyre pressures will give you a much harder ride, so any bumps & stones etc.. even smaller ones may well be felt through the steering wheel and come across ...
Orb's user avatar
  • 5,067
3 votes

Why is it that when supercharging, it's preferred to compress the input, rather than pull a vacuum on the exhaust?

Since the question doesn't specify any type of engine... Funnily enough, there are engines which pull a vacuum on the exhaust. They are steam engines, so the vacuum is created by simply adding cold ...
user_1818839's user avatar
3 votes

Why is it that when supercharging, it's preferred to compress the input, rather than pull a vacuum on the exhaust?

Pumping air into an engine requires work, but each joule spent pumping in pre-combustion air will increase the amount of work that is produced downstream by more than a joule. The effective power ...
supercat's user avatar
  • 291
3 votes
Accepted

What happens when the air-fuel mixture ignites but the piston/crankshaft briefly can't move?

I coped this text from this website This stroke is where the spark plug ignites the air/fuel mixture, creating very high cylinder pressure which rise very quickly. Peak cylinder pressures near TDC (...
HandyHowie's user avatar
  • 25.2k

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