Hot answers tagged performance
14
tl;dr: They do. It's just harder to tell how much.
The longer answer is that they do and that effective compression is failing you as an approximation for actual effects.
Think about detonation (AKA premature ignition of the fuel-air mixture). Normally we consider two causes: compression (the change in the space enclosed by the cylinder as the piston ...
8
The problem is, the crossfire isn't just high compression, I believe its supercharged as well. Forced induction motors like octane - the high pressure, high compression, and most importantly high combustion temperatures make you more prone to detonation.
There are enough electronics in the engine (knock sensor for one) to realize that something is amiss ...
5
Performance exhaust pipes increase power by getting the exhaust gas out of the engine faster. It does this by eliminating the restiction by using larger pipes or less sound absorbing/reflecting material. An analogy is the aerator on the faucet it slows down the output or flow out of the pipe similar to a muffler. Gas mileage is improved by getting more of ...
5
Firstly, the comments made by others are correct. The power used by each of the components listed will vary on a component by component basis and even on an installation by installation basis. The power used by each component will also vary depending on the speed that it is running at. Also the number and type of components will vary from car to car.
With ...
5
On my most recent car before my current car, I put in a K&N air filter.
I believe I saw a minor improvement in horsepower, but it could also have been the placebo effect.
As to your questions:
You can save money with a K&N as long as the following are true:
You clean/oil the filter at the recommended intervals
You don't live in an excessively ...
4
One of the reasons that a turbo setup with the equivalent effective compression is more forgiving of low octane gas than than a static compression setup is that you're not at that compression ratio all the time. Take that honda, for example. At 9:1 static ratio, you can run 87 octane all day as long as you don't push any boost at it. When you do start ...
4
NOTE: the below assumes that you aren't talking about ECU-controlled cars that explicitly pull timing intentionally at high revs. In the spirit of checking the easy answers, you should check the map in the ECU.
If you're looking for measurable factors, there are two critical items that might trigger detonation and, therefore, convince the engine to pull ...
3
This is one of those eternal debates that have very few definite answers.
My view is:
Try lower octane gas, if you notice either knocking or decreased performance then you should stick with the higher octane fuel.
Try midgrade first, then if everything is good, try regular. My mother had a Mazda Miata that recommended Midgrade but would run fine on ...
3
I am looking @ Page 96 of 1999 Toyota Avalon Owner's Manual. This page shows Dash buttons with labels & some nore. This is what written on that page for ECT.
"PWR" (Power) mode for powerful acceleration
ECT
PWR "PWR" mode indicator light on the instrument panel shows the driving pattern selector button is in "PWR" mode.
3
Factory turbocharged cars typically run very little timing on the top end (high RPM/high load) - so what you're seeing via logger may most likely be correct. Additionally to further confound the issue the factory also tunes A/F to a very conservatively rich value @ WOT. Those two factors alone will make a car feel "soft" at higher RPMs.
That's part of the ...
2
In addition to good answer by @Bob:
There are some tricks that can be used to ease the problem:
A knock sensor for detecting premature detonations (and adjusting boost pressure). E.g. Saab APC allows safe use of lower octane fuels.
Injecting water to cool the combustion chambers (instead of excessive fuel)
Per cylinder exthaust thermometers (and ...
2
this sounds just like a clogged fuel filter to me.
The car starts fine because the fuel has had time to percolate through the clogged filter but once that fuel is used up the engine starts starving for fuel because the flow through the filter is not great enough to run normally.
Since it occurs randomly it will be hard to test this. But I would try ...
2
... I'm curious about if such fuel is safe to use in your typical
stock engine on a passenger car
If they've added lead, no. I suspect that it's very unlikely that anyone is selling leaded gas at a common access pump (at the race track, maybe).
If no lead, then it's quite likely fine but a waste of money for most cars and drivers. Cars (especially ...
2
Have a read of this question on the benefits of premium fuel and this one on what you should choose for your car, as it all depends on your engine and its tuning - a high compression engine can usefully use higher octane petrol, but a lower compression engine will just run badly (or fail to run).
Conversely, some higher compression engines can downtune in ...
2
A lot of performance Japanese cars are tuned for higher octane fuels from the factory, and will often pink badly on anything less than 97. I suspect the "Racing Fuel" will have other additives as well. If your car is tuned for 93 it would probably still run on 100, but certainly won't run well. (out of interest, what ratings are "regular" and "mid" - here we ...
2
The higher the octane, the less power per gram the gasoline contains. Use the lowest octane your car needs.
expanding on my answer: It's safe...ish to use on stock engines. The fuel burns cooler and may clog your catalytic converter. You certainly won't see any better power or mileage from it, unless you're tuned for 100 octane. It's sold solely for ...
2
The quickest way is probably to phone a Seat dealer and ask. Usually recalls are "Any vehicle with a VIN in the range X to Y" - so all you need to do is find that range and make sure the car you're looking at isn't in it...
The VOSA Database also has a list of all official recalls on UK market cars or parts, and doesn't list any for a 2008 Leon.
2
Assuming this isn't a daily driver, make sure it is legal locally to burn and start with small doses (2% mix) then add a little more every fill until it doesn't run properly. Then come back and tell us how it went! :) Also, this may foul plugs, ruin O2 sensors and lead to high carbon build-up, but all in the name of progress right?
2
What does it do? (better performance [and how so?]? better mileage?
cooler sounds?)
It depends. One of the goals of a performance exhaust is usually to create a tuned system:
A tuned exhaust system is an exhaust system for an internal combustion
engine which improves its efficiency by using precise geometry to
reflect the pressure waves from ...
1
If I remember correctly you can't generally blend plant-based oils with petrol (gasoline for our US readers) and expect them to burn in the same way, although you can do so with Diesel. This is because petrol is a much lighter oil than Diesel, wheras plant oils, while lighter, are much closer to Diesel.
Ethanol is lighter still ( in fact, after methanol, is ...
1
If you are mixing other fuel , you need make changes in compression ratio and that will depends on the type and amount of the mixed fuel. Other wise your new fuel mixture will not be explode properly then it will emit more carbon and smoke.This will make two problems
More polution- this may illeagl
Ruin engine life- More carbon will cause more friction for ...
1
I wouldn't rule out a bad MAF so quickly - there was a generation of VW and AUDI MAFs that slowly went south without any indication from the ECU that they were doing so and IIRC the ECU managed to compensate for the dying MAF for a while.
Also, if the ECU thinks you might be boosting at 15psi and using a conventional gauge suggests you're boost 7psi, you ...
1
Huh? Baring that, as Rory stated, this really doesn't make sense, what do you intend to do?
Would this be a separate test unit outside of the vehicle, or would the electric motor be providing power along with the vehicles gas/diesel engine? Is the transmission still connected to the clutch, driving the wheels?
If it's outside the car (motor drives one ...
1
i-VTEC is definitely camshaft based - it does have the ability to vary the intake came quite a bit. Honda has submitted the patents for AVTEC but has not yet put them into production.
1
I'm generally suspicious of get rich quick schemes. I've been holding off on chip-like improvements to my car until I'm really convinced that the software is all there and it's a 2004 model.
On the other hand, remember that even a small turbo motor will benefit from attention to the intake and exhaust components. Remember that the engine is an air pump: ...
1
Modifications almost always affect the warranty. The warranty is based upon a standard car used in typical circumstances. If you go outside of those (either by modifying things or using the car atypically (like racing it)) then the warranty is in jeopardy. It comes down to how generous the dealer/company happen to be the day that you need work...
That ...
1
I realize this question has been answered, but keep in mind that any carbureted engine can bog down under throttle and cause a lack of acceleration.
If it can be backed off and regain acceleration, then I'd suggest carb tuning. If the engine revs, but no acceleration then it's a slipping clutch.
1
In addition to the other answers above:
If the air/fuel ratio is too far to the rich side, you can actually get rich knock... So, make sure it's correct, don't just add more fuel blindly.
Vibrations/noise in the engine bay can trigger false knock readings that will cause timing retard. I've seen more than one car that was tuned and working fine, right up ...
1
Temporarily running a higher octane fuel will allow you to determine whether your fuel octane is insufficient for the performance of the engine and/or it's current tune. (For instance the timing may be too advanced for a low octane fuel). You could temporarily run 100 octane unleaded race gas and then compare your timing retard values.
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