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28
votes
5answers
4k 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
133k 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
20k 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
125 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
53k 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 putt"...
12
votes
3answers
9k 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
612 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
5answers
39k 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 ...
11
votes
2answers
15k 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, ...
11
votes
1answer
118 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
545 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
581 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
1answer
69 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
239 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
2answers
71 views

What is the benefit of Forged Internals in an engine? Pistons, etc

I've heard of these for years and not fully understood the benefits, can someone elaborate? Frequently the vehicles with forged internals have serious boost pressures, but I've also heard of naturally ...
8
votes
2answers
77 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
369 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
169k 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
412 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 ...
7
votes
5answers
17k 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
4answers
223 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
394 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 you'...
6
votes
1answer
20k 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
6
votes
1answer
87 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
41k 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
95 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
2answers
111 views

What are the consequences of using an expired tire?

Based on this answer I know that the consequences are less security and low performance. But I would like to know if there is anything else and also explain those two issues and why do they happen ...
5
votes
1answer
99 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
4answers
21k 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
103 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
5k 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
121 views

2012 KTM Duke 200 - Low acceleration in low rpm [on hold]

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
10k 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
19k 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
48k 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
93 views

Remapping a used engine

I appreciate that a performance increasing remap is likely to increase the rate of wear and tear on certain components inside an engine bay. Is remapping an engine that already has 50k miles on the ...
4
votes
1answer
130 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
73 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
394 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
62 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
326 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
4answers
154 views

Increase my cars BHP?

I have a corsa, it's very slow and sluggish. It's my first car and feel like it could do with something to give it a kick. Here's my specs any reccomendations what I can do with it?
3
votes
3answers
372 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
4k 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
1k 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
37 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
147 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 ...