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29
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
8k 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
139k 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
22k 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
134 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
56k 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
3k 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
621 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
40k 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
4answers
110 views

What is gained with “performance” spark plug wires?

When heading to the store to pick up a new set of spark plug wires, I found three products at this particular shop: Product #1: Price: Cheap Boots: EPDM Core: Suppression Insulation: EPDM Max Temp:...
11
votes
2answers
16k 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
126 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
305 views

40MPG at 100MPH?

Around 1987-1988 I had a Ford Fiesta/Festiva. I was in the Army and regularly made weekend trips, driving from southern California to Central Washington a trip of about 1200 miles. I would leave in ...
10
votes
2answers
555 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
607 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
75 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
277 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
96 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
82 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
492 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
178k 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
420 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
233 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
432 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
22k 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
3answers
95 views

Please help with my Intake for Opel Corsa 2014

I have an Opel Corsa D 1.4 turbo. I have bought a Conic Air Filter, but I need to know what I can do to make a better installation. I don't think that I have a good one, because is too close to the ...
6
votes
1answer
92 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
42k 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
99 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
137 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
3answers
50k 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 ...
5
votes
1answer
109 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
2answers
61 views

Why isn't the Pikes Peak Hill Climb used as a benchmark for automotive companies?

I know this is in exactly a technical question but the outcome of automotive companies actually doing this would bring technical benefits that I don't think we're currently doing towards right now so ...
5
votes
4answers
23k 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
120 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
6k 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
125 views

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

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
21k 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
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 ...
4
votes
1answer
96 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
160 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
77 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
402 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
65 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
347 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
182 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
405 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 ...