17
votes
4answers
40k views

Why does a Turbocharger only produce boost when the engine is under load

As per the Title. Why does a turbocharged car only produce significant boost whilst the engine is under load. Is is something to do with how much exhaust is being produced or is there some kind of ...
17
votes
2answers
676 views

What does a flywheel do and what is it connected to?

I understand roughly how an engine works and that there is a crankshaft which is able to turn the flywheel using internal combustion. I have just realised that I have got absolutely no idea how the ...
17
votes
3answers
18k views

Why is my motorcycle losing power when accelerating?

I ride a Honda Rebel 250 motorcycle and over the past few days I find that the bike is losing power when accelerating fast. When I twist the throttle to accelerate quickly (in any gear) I hear the ...
17
votes
9answers
182k views

When do brake rotors really need to be replaced?

I need to replace my rear brake pads. A mechanic suggested I also replace my rotors because they are rusted around the edges. The rotors are in fact quite rusted, however, there is no rust on the ...
17
votes
2answers
678 views

Does resting your foot on the clutch wear it out?

Does driving with your foot always resting on the clutch (not pushing) generally wear it down?
17
votes
4answers
20k views

What are the benefits of low profile tires?

I have yet to find anyone that knows of any benefits of low-profile tires. All of the pros that I've asked have said there is no benefit. Naturally, the number of pros that I have available to ask is ...
17
votes
1answer
530 views

LTFT and STFT values are off and don't make sense

Car is a 2015 BMW M5 and it has an aftermarket CAI and a catback (slip on) exhaust. No other performance mods or tunes. About 6-7 months ago, I bought a Kiwi OBD-II reader, simply out of curiosity ...
17
votes
6answers
58k views

What is causing this terrible grinding/groaning noise when I come to a slow stop sometimes? (but not always!)

Update 11/9/2013 After a good bit of driving, the noise reoccurred. I took it back to the mechanic and we decided it must be the brake pads. They're pretty worn out, and like I said before, they're ...
16
votes
8answers
2k views

Will having a radiator full of engine oil do damage to the motor?

I've got one question; I was looking over this car that I was going to buy and there was engine oil in the radiator. I asked the guys why it was in there and he said he didn't have enough coolant to ...
16
votes
11answers
66k views

Wheel stuck or fused to drum

1997 Chevy 1500 My right rear wheel is stuck or fused to the drum. I can get the lugnuts off, but no luck getting the wheel off. I took it to a tire place and they couldn't remove it either, and said ...
16
votes
5answers
4k views

Why not use gasoline on diesel engines or vice versa?

I've read gasoline engines use sparks to ignite the mixture, but diesel engines use just compression which can't be done in gasoline engines due to high compression ratios which can cause engine ...
16
votes
10answers
170k views

How do I loosen stuck lug nuts in order to change a tire?

How do I loosen car tire lug nuts (so that I can change a tire) when they are really really stuck? I have tried turning the provided wrench, even standing and jumping on it. This worked for 4 of the ...
16
votes
4answers
2k views

When does it make sense to replace a camshaft?

Preamble (Rant) I was reviewing this question in which the OP presents a repair quotation that includes replacing the "intake camshaft" to fix an engine that had overheated. To me this ...
16
votes
5answers
10k views

Adding a additional battery to car

I have purchased a brand new Toyota Innova. I need to install a a mac mini, 2 laptops and make this car a mobile office. I need to know if I can install another car battery in parallel, and will ...
16
votes
5answers
2k views

Aluminium engine vs Cast Iron engine

What is the advantage that the aluminium engines provide over the cast iron engine apart from the fact of rusting and weight reduction. Manufacturers like to boast about their all new aluminium ...
16
votes
6answers
34k views

Does a timing chain need maintenance?

Does a timing chain (as opposed to timing belt) need any specific maintenance? In particular I'm talking about a BMW Z4
16
votes
5answers
5k views

My Car Squeals When Braking Even Though I've Had My Front Rotors Machined and Back Rotors Replaced and all new brake pads. What could it be?

I own a Toyota Soarer SC300 (1994), 2JZ motor non-turbo 3 litre engine. The engine is probably irrelevant, but provided for prosperity. Anyway, the front rotors were machined and are within the legal ...
16
votes
2answers
1k views

Should a mechanical “click” Torque Wrench be set to zero when not in use?

I have a standard click torque wrench. I was told I should set it to zero when not using it in order to keep the accuracy high. Is this true? Secondly, I have not been doing this since I purchased ...
16
votes
1answer
448 views

What is the difference between a 180° V4 and a true boxer motor?

Reading this thread which talks about V4 motors, I am wondering what exactly is the difference between a 180° V4 motor you'd find in a Subaru and a true boxer (or horizontally opposed) flat 4 ...
16
votes
1answer
29k views

How can I repair cracks in leather seat?

The leather on the side of the driver's seat has some minor cracks. I am using conditioner to help prevent this in the other seats but these cracks already exist. Is there a product or patch of some ...
16
votes
1answer
9k views

Is this what is making my car sound like a racecar?

Recently, my car (2000 Mercury Grand Marquis) started sounding like a racecar: the engine became very loud. There's clearly something going wrong with the exhaust system. I'm trying to understand ...
16
votes
5answers
9k views

Manual transmission at stop: 1st with clutch in, or neutral with clutch out? -OR- Throwout Bearing wear

When sitting in traffic or at a long red light, is the Best Practice to have the car in 1st gear with your foot on the clutch, or in neutral with your foot off the clutch? Some say that you should be ...
16
votes
5answers
56k views

What causes battery terminal corrosion?

I put a new battery in my car about 8 months ago. After a problem starting a couple days ago, I found that there was massive corrosion under the battery terminals, so I cleaned them out and ...
16
votes
4answers
1k views

shifting stops when critically low on gas

I have a 1999 Dodge Dakota. It is a V6, 3.9 Liter, auto transmission. I have a weird problem that no one has been able to answer for me. HOW I CAME TO REALIZE THE PROBLEM: One day I was driving ...
16
votes
5answers
32k views

Is it OK to mix oil of different viscosity in a Wankel engine?

I have a Mazda RX-8 (with a Wankel rotary engine). Mazda advises North American owners to use 5W-20 oil. The engine was just replaced 200 miles ago by the dealer so it currently has 5W-20 in it. ...
15
votes
13answers
77k views

How long should I let me car warm up in the winter?

I have been reading mixed reviews about how long to let your car warm up before driving in the winter months. Most of the articles say that the best way to warm it up is to let it idle for 1-2 ...
15
votes
6answers
2k views

Why or why not increase engine efficiency by running the car “fuel-lean” (using a turbo or supercharger)?

Everyone wants their cars to use less fuel, right? I read the following passage about running the car fuel lean from this website: Run the engine fuel-lean, that is, use excess air. It is well ...
15
votes
5answers
2k views

Is there a reason keyless ignition cars do not shut off when it can no longer detect the keyfob?

There's been some security-related questions being asked here and on sister sites concerning keyless ignition automobiles and how to defend against some security risks. This brings up a related ...
15
votes
4answers
39k views

what is difference between DOHC and SOHC?

I want to know the SOHC and DOHC configurations. On what factors an engine manufacturer decides to go with SOHC or with DOHC, what should I choose? DOHC or SOHC?
15
votes
8answers
28k views

My car's coolant temperature reaches almost 100 C / 212 F in a fast pace

Today, after a very hot day, I saw that my coolant was almost reaching 100C/212, I pulled over, stopped and took a look over the hood. The very little water that remained in the coolant tank was all ...
15
votes
2answers
12k views

Why would a new gas cap cause the “check engine” light to shut off?

This happened to a friend of mine: The "check engine" light came on in his truck (Toyota). He replaced the gas cap and the light shut off. Then I also had a "check engine" light come on in my 1994 ...
15
votes
3answers
1k views

Why are there multiple CAN buses in vehicles?

There are a number of questions on the CAN bus but none (so far as I can tell) that explain why there are several CAN buses in a vehicle. From what I understand many different nodes can be connected ...
15
votes
4answers
5k views

Is downshifting on hills harmful for non-trucks? [duplicate]

Possible Duplicate: Does Downshifting (Engine Braking) Cause Extra Wear and Tear? Since the days of taking drivers ed (many years back). I was told that when you encounter a steep or ...
15
votes
3answers
12k views

When car is standing still, I smell Diesel exhaust. Why?

In my 2003 Opel Vectra, the cabin air smells of Diesel exhaust while stopped at e.g. a red light. The exhaust smell goes away when driving, and it also doesn't come back if I turn the ventilation off ...
15
votes
8answers
53k views

What causes brakes to pulsate right after rotor and pad replacement?

I have a 2002 Infiniti Q45. I replaced the front rotors and pads on Sunday. It was the first time I've done this on a car, though I have done it countless times on various motorcycles. I was careful ...
15
votes
4answers
55k views

Symptoms of Lean or Rich carb settings on a motorcycle

I have a 1981 Yamaha XS650. I recently put in K&N stock replacement filter (ie, they are in the airbox and conform to the size of the original), however they may be leading to a leaner mixture ...
15
votes
2answers
550 views

Why did Ducati decide to use the desmodromic valve train rather than a more tradition valve train?

Ducati's use a unique method to open and close their valves. It's called the desmodromic valve train. The desmodromic valve system does not use springs to close the valve, it uses the cam and has a ...
15
votes
1answer
3k views

What is happening when a two-stroke engine is said to be “four-stroking”?

Many years ago, I was involved in a hobby of building and flying model aircraft. The aircraft used alcohol-fueled 2-stroke engines with glow plug ignitions. When these engines ran rich (and always at ...
15
votes
1answer
6k views

Where can I find my car's colour code?

I'm currently shopping around for a touch-up pen to repair some very light scratches on my car. I've found out that our local hardware automotive store can mix the exact colour for any vehicle. ...
15
votes
1answer
757 views

How important is time-based servicing vs. distance-based servicing?

For years I have been driving a very old car, and servicing it every 10,000 kilometres even though it took me almost a year to drive that much. Now I have a newer car which I care about more. It's ...
15
votes
1answer
115 views

Dynamometer Question - How is it operated and what are they doing?

When guys are doing dyno runs they to do it in a gear, interact with the keyboard and then do it again in another gear. It seems they do multiple runs in multiple gears. In this post Paulster ...
15
votes
1answer
2k views

How do I find the correct pins in a CAN-BUS connector?

This question might be too technical for this forum, but I'll give it a go. I have a 2012 BMW R1200R motorcycle with CAN-BUS. I'd like to make an Arduino interface to the connector on the bike, but I ...
15
votes
2answers
9k views

Is Anti-Seize a lubricant, abrasive, or both?

I'll flesh my personal bias at the outset - being a heavy diesel mechanic for a time, and mechanically inclined my entire life, I use Anti-Seize wherever I can. If it has threads and it's not part of ...
14
votes
6answers
567 views

How to keep wheel ramps from sliding?

I have a very smooth garage floor. When I try to use my wheel ramps for the quick and easy way to raise a vehicle, they will often slide, sometimes just one, but other times both. They will sometimes ...
14
votes
6answers
3k views

Turbo equivalent on electric motors

Is there anything functionally equivalent to a turbo for electric motors? Obviously, I am not asking for something that reuses escape gases to force the entry of air, because there are no escape ...
14
votes
5answers
65k views

What does the 'cc' mean on a motorcycle?

I'm relatively new to motorcycles, my flat mate taught me how to drive his two Royal Enfields around New Delhi, and for the past year and a half I've been taking care of them as they break down ;) ...
14
votes
4answers
7k views

Car crash: when does a car catch fire?

Which kind of crash does it need for a car to catch fire? I'm asking because I was discussing about an accident where a car crashed into a full-grown brown bear. Is it realistic under normal ...
14
votes
3answers
418 views

How does the car's ECU detect a misfire?

I was wondering what the specific mechanism used by car ECU's to detect misfires is, or are if there is more than one method.
14
votes
4answers
2k views

Why do 5- and 6-speed transmissions typically need different gear ratios?

My 2013 Subauru WRX has a 5-speed manual, and I long for it to have a 6th gear when cruising on the highway. A friend has a 2012 Subaru STI with a 6-speed manual, and I noticed his car runs through ...
14
votes
3answers
32k views

How is “outside temperature” measured in a car?

Most cars have a display for outside temperature, and I have been wondering how it was measured... In other words, where exactly is the sensor and how reliable is it?

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