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26
votes
5answers
3k views

What are the benefits of a lightweight flywheel and why aren't they lightweight already?

This previous question explains what a flywheel does and why it is needed. That explanation means that the flywheel needs a certain amount of mass to do its job. However, an "upgrade" for many cars ...
25
votes
3answers
7k views

Static vs. Effective compression: Why does higher effective compression not require higher octane gas?

Background I've been trying to do a lot of research on boost lately because I'm planning on running a moderate turbo setup on my daily/light-duty-autox car in the future. I'm trying to get into the ...
24
votes
3answers
121k views

What does a water like drop coming out of the exhaust of the car signify?

Sometimes while driving in the traffic, I come across a car or two which would be dripping water-like drop from it's exhaust steadily in a break of 4-5 seconds. I tried to ask a couple of people at ...
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 ...
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 ...
13
votes
4answers
49k views

What would be the most likely cause of engine sputter?

Most of the time my 2001 Honda Civic sounds like this... Vrooooooom. But some times when I start driving it sounds like this... Vrooom putt pa putt pa putt pa vrooooom. When it's in the "putt pa ...
12
votes
3answers
8k views

Is high octane fuel a requirement for high-compression engines?

I own and use a 2005 Chrysler Crossfire SRT-6 as my daily commuter vehicle. I'm not interested in trying to eek out a few extra miles on a tank, I want to keep the vehicle and its engine running as ...
12
votes
4answers
2k views

How to troubleshoot excessive timing retard?

I've seen numerous cars that for one reason or another, retard timing excessively at wide open throttle - getting worse over time. Seat of the pants impression is that power drops off steeply as RPMs ...
11
votes
3answers
563 views

How do you get more horsepower out of a 1979 Mazda RX7?

Moar Horsepower? The 1979 Mazda RX7 - Desireable Track Car It seems this platform is very popular in club racing today. You see them as prized possessions at SCCA gatherings to simple track days. ...
11
votes
1answer
98 views

How does a dynamometer work?

I don't have much to add here. Pretty simple. How does a dynamometer work? How are Horsepower and Torque measured as separate figures during a single dyno run? There are quite a few components and ...
10
votes
2answers
463 views

Performance Exhaust — what, how, why?

I've seen performance exhaust pipes on sale for cars and motorcycles, and my questions are these: What does it do? (better performance [and how so?]? better mileage? cooler sounds?) Is/how is it ...
10
votes
1answer
543 views

What is a 6 Pack and will it add performance to my engine?

What is a 6 pack in the hotrodding world? Does it improve performance of my engine?
10
votes
2answers
14k views

How much power (HP) do the components on the engine belt generally use?

In general, how much power (HP) to the components on the the engine belt actually use? I'm trying to come up with an estimate of how much horsepower an engine wastes on things like the AC compressor, ...
10
votes
1answer
65 views

How do you plan an engine build?

What must be accounted for when building an engine for performance applications? How do you methodically plan a build? Take for instance a stock Small Block Chevy. Budget I understand with an ...
9
votes
2answers
192 views

What are Performance Camshafts?

I read the following question recently: What is it about performance cams that make engines produce more power when they are installed? I know there are a few components for cars that have "cam" ...
9
votes
4answers
37k views

Differences and Recommendation between Steel and Alloy Wheels for Winter?

There are many discussions regarding steel vs. alloy wheels in Winter on multiple forums. It would be good if someone could lay out full facts and help scale these differences (questions below). For ...
8
votes
2answers
73 views

Does an Engine Strut Bar have any effect on performance?

I just bought a 1988 foxbody and I'm currently working on restoring it and then maybe in the future do some engine improvements. I've had many people tell me to avoid this, as my car isn't going to ...
8
votes
1answer
240 views

Consequences of a Dirty Intake Manifold

This is similar to, but not the same as my question Effects of Dirty Piston Heads and Intake Valves. Basically, I often see people talking about taking the intake manifolds off older cars to clean ...
7
votes
5answers
152k views

What is the meaning of BHP and torque in bikes or cars?

BHP = Brake horse power. It says that it is brake horse power but it is generally relates with high pick up (your bikes reaches top speed in lesser time). So what does this actually mean?. Torque = ...
7
votes
4answers
398 views

Assuming identical and sufficient ABS, and ignoring aerodynamics, are tires the only factor for braking distance?

I had my first accident two days ago (minimal injuries so don't worry about that), and it's got me thinking about a lot of different aspects to driving and cars, such as braking. Had my braking been ...
6
votes
4answers
206 views

Cheap vs Expensive Fuels [closed]

What is the difference between the cheapest fuels in a place like Tesco's and the 'high quality', highly priced competitors? Is there actually any noticeable difference in available power, engine ...
6
votes
3answers
335 views

Does Max Power RPM Equal Max FE?

I was looking over the specs for a 98 Mazda 626 2L and noticed that it says the max power is at 5500 RPM. Will the Max Power RPM also be the RPM at which the engine is most efficient assuming ...
6
votes
3answers
16k views

How to extend the life of the dual mass flywheel in a diesel engine?

I am looking for ways to improve the life of the dual mass flywheel (DMF) in my 2005 Ford Focus tdci. I have heard that they can wear out quite quickly on the Ford Focus if they are driven in city ...
6
votes
1answer
74 views

Why do modern vehicles omit a temperature gauge?

I'm more specifically interested in performance vehicles. My current car has gauges for coolant temperature, oil temperature and oil pressure. The coolant temperature gauge is there so you can tell ...
5
votes
6answers
39k views

Racing Fuel (100 Octane Rating) - Better than Premium?

Earlier today while driving out East on Long Island I stopped to fill my tank with gas, and at the station, all the pumps had the usual Regular, Mid, Premium on one pump, but on the 2nd pump which ...
5
votes
3answers
92 views

What is a good strategy for adding performance upgrades in phases to a 2013 Mazda 3?

I have a 2012 Mazda3 s (manual transmission, base engine) to which I'd like to begin adding more performance-oriented parts once the OEM parts begin to degrade. However, I am not the kind of person ...
5
votes
1answer
87 views

How to increase horsepower? [closed]

How can you increase horsepower on an engine through general modifications without modifying the internals of the engine? Are there benefits or tradeoffs from doing so? What kind of things could I ...
5
votes
1answer
17k views

What are the differences between a wet motorcycle clutch and a dry motorcycle clutch?

What are the differences between a wet motorcycle clutch and a dry motorcycle clutch? More specifically, what are the differences in applications performance reliability maintenance/repair
5
votes
4answers
18k views

Random RPM jump when accelerating hard

I should state first off that I'm not much of a car guy when it comes to the actual mechanics behind them. I just wanted to check if there's anything going wrong with my transmission. I drive a 03 ...
5
votes
2answers
87 views

How much horsepower to expect from a cold air intake in Dodge Ram

It's a 1999 Dodge Ram 1500 4x4, Laramie SLT, automatic transmission, 5.9l magnum engine, and crew cab (222k mi). I have a friend who could put a cold air intake on it, with a new hood. But I have ...
5
votes
4answers
4k views

What could be the reason and solution to a sudden drop in mileage?

Got my Suzuki Swift Diesel serviced two months back, and all of a sudden the mileage dropped from 20kmpl to 12kmpl and that is confusing! After i returned to Service shop, the guy said that there is ...
5
votes
0answers
104 views

2012 KTM Duke 200 - Low acceleration in low rpm

Recently my bike (KTM Duke 200) is suffocating to deliver enough power between 2000-3000 RPM. I took the bike to a service station and they told me that its an engine problem, low compression and ...
4
votes
2answers
9k views

Audi A4 2007 2.0T boosts but poor performance, fuel economy

My 80,000 mile 2.0TFSI Turbo Audi has lost a lot of performance but produces no check-engine-light (CEL) or codes. One month ago an independent garage looked at it and did $2200 of work including ...
4
votes
1answer
17k views

How much does displacement affect performance?

I'm interested in learning more about the steps that can be taken to increase the performance of an engine. I'm curious how much displacement affects performance. For example, compare the following ...
4
votes
3answers
45k views

What is ECT Mode for? - Toyota Cars?

I'm not sure if this is a feature on Toyota cars alone, but I currently drive a '99 Avalon XLS and in addition to the D3 mode which I know disables overdrive, right above the radio near the top of ...
4
votes
1answer
91 views

2011 Infiniti G37 - Throttle Response Issue

When I step on gas in my G37 the throttle response is a bit lagged. It has increased ever so slightly over the past 6 months. Can someone explain what the cause of this might be and any preventative ...
4
votes
1answer
69 views

Ford TDCi 1.6: more performance in cold weather

For some time, I've had a problem with the performance of my Ford Focus 1.6 TDCi (Diesel): when accelerating hard in the 3rd or 4th gear, there was a performance drop and I sometimes had to go off the ...
4
votes
1answer
381 views

How much longer than a copper plug will an iridium plug last (on average)?

I've been hearing a lot about iridium spark plugs lately. I have read claims that these plugs are more durable than copper plugs due to iridiums high melting point and anti-corrosive properties, but ...
4
votes
0answers
58 views

What will upgrading the Camshaft do to my BBC 454?

I have been told that upgrading the Camshaft in my GM 454 will increase performance. What will this do exactly and what will the engine actually gain? 10069286 block casting 454cu '90-'91 MY, Mark ...
4
votes
0answers
297 views

Power loss in Nissan Primera SVE. Possible causes?

I have a Nissan Primera SVE (2002 model). Mileage is about 200000KM. Had its timing chain replaced at the end of 2013 because it was "stretched". Since then, I haven't had any problems (up until now). ...
3
votes
3answers
322 views

Are there any negative sides to using multiple air filters?

My question is actually quite simple. Do you get any performance/sound/feel differences while driving with multiple air filters? For example, the stock filter that's built into most engines: and an ...
3
votes
2answers
3k views

Wheel offset effect on performance

When it comes to upgrading wheels and tires, drivers tend to have two different goals in mind: Improving their vehicle's handling/performance Improving their vehicle's appearance A lower positive ...
3
votes
1answer
975 views

Using an open vs closed clutch cover on a motorcycle with a dry clutch

A common modification I've seen on motorcycles with a dry clutch is to replace the closed clutch cover with an open one. Besides the visual and auditory differences, will I notice anything else ...
3
votes
1answer
32 views

Sporadic speedometer, and performance lags when speedometer not engaged

I have a 2000 Honda Accord, 2.3L L4 with a 5-speed manual transmission. Recently, the speedometer has been sporadic- sometimes accurate, sometimes bouncing around, but mostly sitting at 0. I replaced ...
3
votes
5answers
116 views

1980s motorcycles and engine size: still good performance?

A buddy of mine is considering a fix it upper road bike for fun and to learn (prior dirt bike rider). I still go by the rule of thumb that 600cc is iffy for beginners but a lot of used 1980s bikes are ...
3
votes
5answers
4k views

Why does my automatic 2002 Honda Accord EX V6 seem to struggle when shifting gears?

It's happening more and more these days where I will hit the gas while at a complete stop. My car starts moving, but not as fast as it should based on how far I have the pedal down. Anymore, I can ...
2
votes
2answers
109 views

Replacing Spark Plug with Laser Iridium NGK Spark Plug

I have 2012 KTM Duke 125 at 10 000 miles (16k kilometers). I am the third owner of bike for 2 years. Whenever i twist the throttle fastly, motorcycle is chocked up. So i thought the problem could be ...
2
votes
2answers
2k views

Should I get a reusable/washable air filter for my Kia Soul?

I've got a 2010 Kia Soul, and I was wondering if I should get a reusable/washable air filter, such as the K&N 33-2960. The reasons I would think to get such an air filter would be: Save on the ...
2
votes
1answer
3k views

What (if anything) does the Sport button on a Mini Cooper do?

There is a button next to the stick shift labelled Sport. It feels like it just re-maps the throttle so the pedal is more sensitive, but does it really change anything about the performance, ...
2
votes
3answers
96 views

Alternate fuel for motor cyce

In some countries, Government mixes ethanol with petrol & diesel and distributes it to their consumers. This will save some of their imports. My question is Can I blend petrol with Zatropha ...