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24
votes
6answers
2k views

When is a cold air intake system beneficial?

Cold air intake must be one of the popular mods there is, and one subject to the most controversy as well. Manufacturers of such systems advertise 5-20 HP gains, yet there are claims that this mod ...
18
votes
6answers
1k views

Will higher octane fuel improve towing power?

According to Will higher octane fuel improve gas mileage? higher octane fuel does NOT notably improve fuel efficiency. Will higher octane fuel, increase power while towing? I looked online and ...
14
votes
5answers
69k 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 ;) ...
13
votes
6answers
542 views

What is the difference between torque and horsepower?

A very basic question - what is the difference between torque and horsepower? Its all over Google, but I am really confused and can't get any satisfactory answers. I'll tell you my confusion: Torque ...
12
votes
4answers
29k views

Engine power specification at different rpm?

Car companies advertise power of an engine at different rpms. Car 1: 80 PS at 6000 rpm Car 2: 85 PS at 6500 rpm What does the power at different rpm mean? Does it mean Car 1 has better power than ...
10
votes
6answers
83k views

The battery is fine but my car will not start not even a clicking sound

When I turn the key in to start all the lights on the dashboard go out completely and when I turn it back to the off position the dash lights back up. What could the problem be if the battery is okay? ...
9
votes
1answer
244 views

How does intake manifold runner length effect the power curve of a car?

Recently I learned that a number of things such as the cam profile, compression ratio and the intake manifold runner length and volume can all effect the power curve of the engine. Here is an ...
7
votes
6answers
60k views

How many amps should my car pull while it is turned off?

I've recently started having a bit of trouble with my car. I typically drive my car to and from work each day. A couple weeks ago I went on vacation and when I returned, my car battery was as dead ...
7
votes
1answer
204 views

What should one do to reduce the HP lost at the wheels on an automatic transmission?

I have a 1990 Toyota Supra Turbo 4 speed auto. I've done some research about automatic transmissions and manual transmissions and what are the positives and negatives of each. (For example, MT is said ...
7
votes
2answers
98 views

How can head port volume affect the power curve of an engine?

Recently I learned that even more things other than the ones already mentioned here can effect the power curve that is produced by the engine. Here is an example of one. I understand that there are ...
7
votes
1answer
159 views

Rattling sound and loss of power

My brother's '85 Toyota Camry with ~190k miles started making a funny rattling sound and lost about a quarter of its power. The rattling seems to come into play when it's under load, like when he's ...
7
votes
0answers
32 views

No power but battery, alternator, and connection are good

This involves a company truck, 08 Chevy Silverado. I am not a mechanic or DIY nor do I play one on TV. The problem I am having is that every 2 or 3 months this truck will not start and completely ...
6
votes
3answers
790 views

Will an auxiliary battery hurt a vehicle's alternator?

I am going to be road tripping and living out of my SUV for a while. I need a way to power a tiny portable cooler/fridge 24/7 and would like to be able to power my cell phone, laptop, and maybe a few ...
6
votes
1answer
684 views

Measuring Horse Power and torque without a dynamometer

I know I can take my car to a workshop and have a Dyno Run and can read the HP and torque figures from that. What I want to know, is there an alternative way to know the HP and Torque figures without ...
6
votes
5answers
14k views

How does cold, dry weather affect horsepower?

It's now properly winter over here in Australia, and the butt dyno is very favourable of the cold, dry air. It's like a free cold air intake for everyone, right?? I can think of two scientific ...
6
votes
3answers
251 views

lack of acceleration mazda 3 sport

I have a mazda 3 sport diesel on a 07 plate it has 133000 on clock, I bought this car a couple of months ago and have noticed a lack of power in the lower gears. it struggles to overtake unless I have ...
6
votes
2answers
88 views

Car battery appears good but car won't start

My 2005 Nissan won't start today. Battery is relatively new(about one year old) and I can turn the lights on, front headlights, and it appears fine. However, when I tried to start the car by turning ...
6
votes
1answer
72 views

Where can I find a power adapter to run a car stereo from a wall outlet?

I have a car stereo head unit that I'd like to repurpose as a radio for my garage. Given that, I'm looking for some kind of power adapter / transformer that I can plug into a wall outlet and splice ...
6
votes
4answers
2k views

Why does the power output peak and then drop as engine speed increases?

I have been looking at the power bands for my car (2000 Opel Agila 1.2) recently, as I want to work out when it is best to change gear and stuff, as I have no life! This is the approximate graph I ...
6
votes
3answers
208 views

Loss of engine power when using headlights

i have a nissan march 2003 (K12). when i turn on the headlights, it loose its engine power. alternator and battery are ok. anybody knows what would be the cause? thank you in advance. additional ...
6
votes
1answer
399 views

Citroen C4 - Poor idle and low rev performance?

I have a Citroen C4 1.4 with 1360cc 16V KFU / ET3J4 petrol engine with 120.000 km. This problem appeared 3 - 4 years ago at around 40.000 km. When the engine is cold / hot there is a flat spot ...
6
votes
1answer
194 views

how do i know if my lead-acid battery has been resurrected?

The OEM battery in my 2008 Jetta SE 2.5L has been nearly fully discharged one month back (had insufficient surface charge after a prolonged use without the engine running, but leaving it idle for 20 ...
5
votes
5answers
2k views

What good is it for an engine to have lower CCs and higher BHP?

I was watching "The Perfect Road Trip 2" by Top Gear, where at some point Richard Hammond is driving a Mercedes A45 AMG. He says that the car develops a whooping 355 BHP, and all that comes from a ...
5
votes
3answers
239 views

Need to source PD-pump for small engine dyno school project

I am making a dyno to measure go-kart engine torque for a high-school project. I would like to use a water brake by varying input/output through a water pump and have read that this should be a ...
5
votes
3answers
1k views

Larger cylinder volume, but less power, how?

KTM Duke 200 which has an engine of 200 cc, and, on the other hand, Royal Enfield Bullet 350 with a 345 cc engine. I.e. Enfield has 150 cc more than the Duke. But KTM produces 25 BHP of power, whereas ...
5
votes
3answers
4k views

Does accelerating faster worsen fuel efficiency?

I've often heard that accelerating harder makes for bad fuel efficiency, but have yet to be given a sound explanation of why. Naturally this makes me question this advice. Now obviously when you ...
5
votes
1answer
114 views

Honda Shadow VT750 louder exhaust noise, low power

Recently, my motorcycle got smashed by my girlfriend (who was driving behind me) in the rear. As a result of the impact, I got propelled into the rear of the car in front of me. Both fenders are ...
5
votes
1answer
90 views

Engine weakening for Bajaj pulsar 220F

Everyone knows that apparently a bike looses it's power with age. But I refuse to agree to this. Shouldn't proper care allow your bike to maintain its pickup over the years? I own a 2014 Pulsar 220 ...
5
votes
1answer
76 views

What is the general rule, if one exists, for determining the difference between crank horsepower and wheel horsepower?

If a vehicle has a known crank or wheel horsepower rating, is there a method that can reasonably estimate what the other horsepower value should be? If so, what is that method? For example, if a ...
5
votes
2answers
6k views

Problems with Power Door Locks

I have a 2009 Honda Accord with approximately 95k miles. About 2 years ago, I began having periodic trouble with the rear driver's side door lock. All other doors would lock/unlock with the power ...
4
votes
2answers
96 views

What's an acceptable battery power drop on light load?

After an overnight rest in the warm weather (above 16 degC), unlocking my 2008 Jetta 2.5L SE, my OEM battery with the minimal "welcome" electronics -- remote open of the driver door a few seconds ...
4
votes
2answers
229 views

Can I use any portable powerbank to jump start a car

Say I have some ordinary portable powerbanks I use for my smartphone, I wonder if all of them are able to jump start a car with flat battery as long as I have a correct connector (e.g. clamp). Or ...
4
votes
1answer
38 views

Re-wiring Harness in Jet Boat w/ Ford 460

I'm replacing the wiring harness on my jet boat. It has a Ford 460 in it. The boat has five gauges on it. A tachometer, oil pressure, amperage, fuel gauge, and water temp. There is also a toggle ...
4
votes
1answer
211 views

Battery high voltage

I measured my "cigar socket / outlet" with a multimeter. Instead of 12v it had 19v. Is this normal? Is it my voltage regulator, alternator, battery that has problems? Car: Peugeot 307, 2.0 XSI 2003 ...
4
votes
1answer
163 views

Could 1.9 Nm be enough to accelerate 130kg electric go-kart?

I'll apologize in advance for a fuzzy question. My problem consists of two parts. For starters, I'm trying to buy a DC engine for learning purposes and most of them only specifies the watt (which I ...
4
votes
1answer
255 views

97 Jeep Cherokee check gauges light came on and then my battery gauge dropped down to 9 didn't lose any power?

I'm so confused I had just left my house and got 3 blocks away and my check gauges light came on, then my battery gauge dropped down to 9v. My Jeep didn't lose power, and the radio, heat, lights and ...
4
votes
3answers
1k views

BMW e36 320i motor looses power significantly out of a sudden

I have a 1992 BMW e36 320i, when i start in the morning, or in cold weather, the cars functions normally and has a lot of power. However, after a little, or when the weather is hot, the car ...
4
votes
1answer
59 views

Power Steering Pump Leak…Wrong Fluid Used

I recently had to have the engine replaced in my '05 Toyota 4Runner. I got it back about 4 weeks ago and about a week ago I discovered a leak at my Power steering pump. When the engine is running the ...
4
votes
2answers
7k views

how fast does the alternator charge the battery?

It would appear that the common word of wisdom is that car alternators provide 50A of output. I actually looked at the supposed specs for my 2008 Jetta 2.5L on the internet -- a compact car -- and it ...
4
votes
1answer
42 views

ENG PWR REDUCED 2009 Chevy Cobalt LS

I have a 2009 Chevy Cobalt bought used a year ago from a dealership near me. It has about 81,000 miles on it and just recently started messing up. My coolant temp will start heating up to about ...
4
votes
1answer
88 views

Alternator/Battery power question

Good Afternoon, I have a 2014 Ford Focus SE that i use as my Work Vehicle. I work in Emergency Roadside Assistance. I have to run a laptop In the car in order to direct calls to other employees and ...
4
votes
0answers
87 views

SAAB 9-5 wagon throws P1549 Code (Boost control valve)

I called an ASE-certified mechanic. He charged some $60 for the visit and $60 diagnosis and really he didn't quite spot on anything. Left me where I was - work-wise , diagnosis-wise and ...
3
votes
3answers
64k views

Possible reasons for loss of power, engine shaking, and smell of liquid fuel (not burning)?

The car (Renault Megane 1998 1.6e hatchback) lost power (about 500rpm in a bursty rhythm) after I re-ignited on a traffic light, the engine started shaking, and I could smell liquid fuel. There was no ...
3
votes
4answers
373 views

Mondeo MK3 power consumption and damaged radio

I'm not quite sure if this is the best Stack for my question but I will try. So from some time I noticed that in my car when engine is turned off there is still quite huge power consumption which ...
3
votes
4answers
261 views

Why dual motor Tesla has more autonomy?

Maybe the question is more appropriate for Electronics Stack Exchange, I don't know. In the page http://www.teslamotors.com/models if we scroll down we see the several flavors Tesla sells its Model ...
3
votes
3answers
4k views

Does a car lose its pickup with age?

I bought a used 2001 Lexus ES 320 with 195K miles on it. It drives well, but I feel its pickup is not as good as I would expect from a 3.0L V6 engine. By pickup I mean the time it takes for the car to ...
3
votes
2answers
262 views

2006 Mustang GT: Left car for 1 week, no power when returning

I went on vacation for a week. The car was working fine before I left. I came back and there is no power. Can't turn on headlights or unlock/lock with remote, and the car gives a clicking sound when ...
3
votes
1answer
197 views

Will a 12 V cooler box significantly affect the performance/gas mileage of my car?

I have an Apollo brand 12 Volt Cooler/Warmer, designed to plug in to my car's 12 V cigarette lighter. I am wondering if the power this device uses will significantly affect my car's performance or ...
3
votes
1answer
224 views

MX5 lost power after spark plug change

I own a Mazda MX5 mk2 1.6L. I had severe problems with engine misfiring, caused by the valve cover seal, to leak. The oil that was leaking was concentrated near the spark plugs, and periodically it ...
3
votes
1answer
238 views

A Suzuki GZ125 marauder that won't power on at all

I've been having a problem with my bike. I went to go to work in the morning and it turned on ok. Left to run for a few minutes then cut out. It turned over again and same thing ... I tried a third ...