Questions tagged [performance]
The performance tag has no usage guidance.
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Overhauling EJ25 with arround 250k miles. Does it make sense to replace the main bearings and rings?
Doing a head gasket/timing job on an Subaru EJ251. As I type this I have it down to heads on a bench and a short block on an engine stand... but now I'm wondering if I shouldn't just take it all the ...
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What are the consequences for having a mismatched inner diameter for an exhaust system
I’m installing my new exhaust system including Headers 60mm inner diameter at exit, down pipe 60mm inner diameter throughout, front pipe 80mm, and cat back 60mm
My question is…
I’m I going to regret ...
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There's no replacement for displacement
I grew up with the saying "There's no replacement for displacement" when referring to engine size, performance, etc.
Does that saying still hold true today?
It's getting harder and harder to ...
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CB400SF Hyper Vtec Spec 3 Sluggish performance @ 5000 rpm onwards
my 2005 CB400SF is experiencing sluggish performance at 5000rpm onwards. I deemed it sluggish because the sound is not as "smooth" as before. It behaves like how a rev limiter would. Vtec ...
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Brakes slowly locking up while driving
Hello everyone I have a 2001 Honda Civic dx that I just bought as a commuting vehicle to replace my wrangler. The only problem with it is that the brakes slowly lock as you drive it. I was told it was ...
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What kinds of tuning can ruin a car's ability to pass emissions testing?
Suppose I want to tune a car for performance, like doing an ECU re-map for a Toyota Supra.
Could this affect the car's ability to pass emissions testing? If so, how?
And in general, what kinds of ...
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Does the engine oil affect the top speed of each gear
I have an R15v3 with 4.5km mileage, just recently I had no choice but to use semi synthetic oil because the shop I bought the oil from gave the wrong product, now I feel that my engine "roars&...
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ECU tuning exhaust - why?
When a sports exhaust is fitted to a car apparently a re-tune of the ECU is required. For a simple example consider a regular unmodified normally aspirated petrol car which then has a sports exhaust ...
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How to design an exhaust pipe to increase scavenging at specific RPMs
Good day all.
I'm looking for advice on an exhaust design problem. It is easy to find videos explaining exhaust scavenging, but how do you control it? Surely there must be some physics that can be ...
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Performance brakes on the front axle only. Bad idea?
Here is the back story. I have a 5yo Jeep Wrangler Unlimited Rubicon.
I do a lot of long-distance driving as well as off-roading whenever possible.
My vehicle is mostly stock with the exception ...
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What causes a vehicle/engine to lose power over time? [closed]
Considering normal everyday use. What factors may cause a generic vehicle/engine to lose some of it's power over time? I recently did a dyno test and noticed that my torque output has decreased ...
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Improve performance on Golf 1.6 diesel [closed]
I have a 2011 1.6 TD golf estate.The car looks fantastic as it's has darkened windows and Audi alloys but has terrible acceleration,so can this car be chipped to improve the performance?
I will even ...
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wheel offset and effect on car geometry
I have a Subaru WRX which is about to have Brembo calipers and disks.
The OEM wheels at 17x7J and 55 Offset do not clear the Brembo calipers.
After spending days measuring clearance from wheel hub, ...
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What is the purpose of this hole in cylinder head?
What is the purpose of this hole in cylinder head bottom?I dismantled cyl.head and change a new one but when I opened the cooling water, water is coming out to this hole.Is there a possibility that ...
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Why are high performance electric cars promoted as requiring no gearbox?
Why are high performance electric cars promoted as requiring no gearbox? Moreover, why don't they have gearboxes ("a gearbox" in this context implies a gearbox with multiple selectable gear ratios)?
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How often and for how long a motorbike (Honda CBR 919 RR Fireblade) needs to run in order to be healthy?
I love my motorcycle but I have been thinking about coming to work by bicycle sometimes.
My motorcycle is a 1998 Honda CBR 918RR Fireblade
I currently use it every week day. On Mondays, after being ...
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Optimizing temperature and spark for horsepower
I recently completed a heads+cam project on my car to increase horsepower. I ended up falling about 50hp short of my goal, and am looking for every little knob I can turn to eek out that last little ...
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What transmission can I join to a 2JZ GTE to support 600 bhp in a Lexus IS300?
I've been researching various transmissions that are popular to connect to a built 2JZ GTE engine. It looks like a popular choice is a Magna PT V160 6-speed manual. However, I'd like to know if there ...
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What could be the problem with my Range Rover going off when driving? [duplicate]
What could be the problem with my Range Rover going off when driving? I need to stop and restart it over again at times it doesn't pull after restarting , I need to wait for some few minutes before ...
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Issues after installing performance headers in civic ek
I own civic ek sedan with D16Y4 engine with auto transmission. I have installed performance headers 4-2-1 after installation I faced an issue during low rpm (during heavy traffic), engine started to ...
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Poor performance
I have a 2005 chevy avalanche 5.3L 4wheel drive. The vehicle starts and runs good and you wouldn't think anything was wrong with it while driving. That is until you step on it. If I were to spin my ...
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Is there a difference between unleaded and premium unleaded fuel?
As far as I'm aware the octane rating is the important thing so in th uk, using super unleaded(97) or v power(99 i beleive) gives the superior performance.
I have seen 'unleaded' which says its 95 ...
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Does having no oil/thinner oil make an engine feel more revvy/lively?
I saw a comment which said if you run with no oil this would make a car sound and feel more revy and lively etc(though it wouldn't last very long). Is this true?
Personally when I've been low on oil ...
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High Idle in Tata Manza, occasionaly
I have noticed that the diesel car idles high (1400-1600 RMP) in Idle. This is occasional and some times the engine check light comes on and goes off.
scanned the system, but was not able to find ...
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Honda Dio performance reduced after 9000km
I see a drastic performance reduction on my 2017 Honda Dio gearless scooter which has just completed 9000km. I just went back to the service center and the guy there, after riding my scooter said the ...
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Performance Modifications for the EJ253 - Throttle Body Spacer?
I've got a 2007 Subaru Forester school-bus, with a EJ253 N/A mated to a 4EAT A/T.
So I've done some mild Googling, and came across This Great Post.
Deep in there is this gem:
THROTTLE BODY ...
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2011 Chevy Impala was inactive with dead battery for 3 months! I have tons of problems now! Help!
In late December 2017, I discovered my 2011 Impala wouldn’t start.
My boyfriend and I jumped it with our other vehicle and it worked. We disconnected the cables and left it running for a while. We ...
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High or low octane and mileage? [duplicate]
I understand that you want to use the octane that your car calls for.
Higher octane cost more at the pump. Ethanol aside, are there instances in climate or the terrain where a shift in octane level ...
user22295
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Sienna lurching, loss of power
OK drove my previously functioning 2000 Sienna, it was driving fine/like normal for a minute, then it started "lurching" when I hit the gas. Felt like it was losing power or starved or something, it ...
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Increase bike speed with acceleration
I enjoy bike riding very much and thats the only medium I use to commute. I have a 200cc bike and it is pretty decent in performance and speed.
Now here is what happened. Recently I watched a video ...
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Does cooler air improve turbo performance?
When modifying NA cars I've always been advised to try and protect the intake from heat soak from the engine bay because the engine performs better with cooler air. This makes sense.
I now have a ...
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760li M performance G12 overheating brakes issue
We recently got BMW 760li M performance G12. It has the M blue brakes system, see image below.
When driving in extreme mode (it is for officials, almost always in rush mode) the brakes do not ...
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Polishing internals?
How should I polish the internals of an engine to create a smooth and carbon free surface?
I am just wanting to polish the internals with little to negligible amounts of metal being removed.
I was ...
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Is it more efficient to drive with the windows down or the AC on?
When driving, is it more efficient (in terms of gas consumed) to use the air conditioner, or to drive with all of the windows down? While the air conditioner reduces efficiency through drag on the ...
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Honda civic 1997
PLEASE HELP!! I have a honda civic 1997 and I've just started these classes a couple towns away so I have a 45 minute drive 5 days a week for 3 weeks. I have been forgetting to put oil in it. My car ...
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Why do most performance cars have longitudinal engines?
Why do most performance cars have a longitudinal-mounted engine?
By performance cars I mean sports cars that typically develop at least 400hp and are usually coupes two seaters.
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Why has my 02 Forester lost power?
Engine has new head gasket-water pump-timing belt-new radiator. Now I have no power going up hills. Transmission does not shift in sync. Cruise control shuts off going up hills. Check engine light ...
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Captiva problem
My Captiva Diesel 2007 has a problem going on a distant journey. During short or town drives, it is fine.
When it turns to be a long journey, the car turns off after a while.
My mechanic tried a ...
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3 rings vs 4 rings pistons: which design is better?
The engine I'm rebuilding (Skoda Estelle/120, 70's, RWD, rear mounted engine) was manufactured with two different pistons, depending the fabrication years: one piston kind has 4 rings and a cut from ...
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Same engine but different intake manifold design: which one should I use?
The engine I'm rebuilding (Skoda Estelle '72, RWD, rear mounted engine) is the same from previous models, with slight different changes. One of the things they modified was the intake manifold which, ...
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Manifold vacuum vs performance
I've been reading around looking for data on how to interpret manifold vacuum. Why? Well, my original thought was that 0.0hg meant that there was no restriction in the intake system and would mean you'...
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Any means to add more batteries to an electric car?
A lot of the electric cars available today (except Teslas) have too small ranges. Inspecting them I see a lot of trunk that I might want to relinquish in exchange for extra range.
However I don't see ...
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Will eliminating factory catalytic converter have effect on emission testing?
I'm not exactly a car guy or know much about cars, but I would love to get some performance headers installed. The problem is that the headers that I found for my car state the following "Eliminates ...
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1992 Ford F-250 4x4 5.8l 408ci stroker tuning questions
I have a 1992 Ford F-250 4x4 w/a 5.8l blocked 408ci stroker attached to a ZF 5 speed tranny running 3.55 gears. On the engine sits a set of 64cc chambered, 190cc intake runner, 70cc exhaust runner, 2....
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What is the difference between Stage 1 & Stage 2 Performance chips for an '89 S10 Blazer?
I have an '89 S10 Blazer with a 4.3 L V6 TBI engine. The motor is all stock and I was thinking of putting in a performance chip in it to get some power out of the V6. I came across the terms stage 1 ...
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What are performance requirements for heavy (commercial) trucks? [closed]
As far as I understand it, DoT regulates heavy trucks on U.S. roads. But I've searched and inquired and I can't find any specific performance requirements that a truck must satisfy to be road legal. ...
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Performance Issue - 2009 Infinity FX50
Please, I need help. My care is shaking and this code is appear in comp test p0021 int/v tim cont-b2 1t
Please ..i clean the intake valve control timing on both side then after that this code ...
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Water like drop coming out of the exhaust of the car stops? [duplicate]
Earlier, water like drops come out of the exhaust of my car. I searched web, and it shows that its a good sign. But for last few months after a regular maintenance cycle (Oil, Oil Filter, Air Filter, ...
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Engine gradually loses power while driving highway speeds
When driving my 2006 Ford Fiesta continuously for 6 to 7 hours, maintaining an average speed of 100-120km/h, i can feel the engine gradually gives less power, and it shuts down after. There is no ...
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Resonance Chambers on Four Stroke
I've seen some full exhaust system which came with a resonance chamber on header pipe for four-stroke motorcycles, this header is shorter than the original one
As you can see the original one has a ...
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