TECH TALK - ask your technical car questions

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baumaxx1
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Re: TECH TALK - ask your technical car questions

Post by baumaxx1 »

@steelsnake-who in the world is Ralph Wiggum?
"Slow" kid from The Simpsons. #-o
Hm, I'm having trouble thinking of any. Care to name a few?
Ford Taurus, Cadillac Allante, there are probably others. Muscle cars were awesome, but it's never been quite the same since. Watch Jeremy Clarkson's motorworld for an idea of why people bag American cars, lol.
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Re: TECH TALK - ask your technical car questions

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Striker94 wrote: @the stig-was it you who put the rank there in the first place? I sent you a PM and you never replied.
never put the tag on your name, can't remember getting a PM from you, I think you have to look further to find out who gave you the name, and no I don't know who did it.

It's not only the handling that is often the problem with American cars, it's also that the american carbuilders think that size equals luxury, so a big car in their minds is luxurious, and while they are often huge on the outside you get very little USEFULL size on the inside, and they have no clue on what luxury then really is, cause they way to often use very cheap materials to build the car so it looks and feels very cheap.
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Re: TECH TALK - ask your technical car questions

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yeah, you've got a good point there... Often they can seriously mess up their thoughts. Big CAN equal luxury, if blended with the right elements of colors, materials and so on. This is what the designers failed on.

You know what the funny thing is? The longest truck is american, the biggest truck is american, I'm pretty sure the biggest car is american, and americans have the biggest biles AND cars AND trucks. AND they have the biggest ships in the navy...

I mean, IMO if you wanted luxurious interiors go to an Audi... (it's not quite as expensive as a Rolls-Royce :wink: )
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Re: TECH TALK - ask your technical car questions

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That's because most American think that bigger is better... wich in most cases isn't but he...
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Re: TECH TALK - ask your technical car questions

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Call me an idiot, but here's a random question-why don't they made supercar engines from titanium/aluminium etc.?

I mean, I don't know much about engines, but why not? A titanium engine would be stronger, lighter and more heat-resistant than a steel one...
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Re: TECH TALK - ask your technical car questions

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Striker94 wrote:Call me an idiot, but here's a random question-why don't they made supercar engines from titanium/aluminium etc.?

I mean, I don't know much about engines, but why not? A titanium engine would be stronger, lighter and more heat-resistant than a steel one...
... they do make engines out of different materials. Cost is a factor, but it shouldn't be an issue with supercars. It all depends on the car.
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Most cars these days have engines with aluminium blocks and heads**. Many other components are also available in aluminium.

Titanium is used for valve springs in exteme race applications (and maybe other parts, not quite sure), but it's not an ideal material for most components for a number of reasons:

1. It work-hardens, which means it becomes harder and more brittle as it gets pounded around inside the engine. Therefore titanium is not very durable.
2. It's a poor conductor of heat. Aluminium is a very good conductor.
3. It's very difficult to machine.

Finally, the cost of making a whole engine from titanium would be astronomical.


** except diesel engines, which are made from cast iron.
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baumaxx1
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yeah, aluminium alloy is very common.
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i thought aluminum warped with alot of heat.
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viper16 wrote:i thought aluminum warped with alot of heat.
The cylinder liners are steel, most of the time.

If they are alu, it's usually a silicon/aluminium mix. The silicon works to dissapate the heat but isn't in such a quantity that it weakens the aluminium.
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I've heard of engines being made with carbon fibre (such as the Koenigseggs), but what components of the engine are those? I can't imagine being able to mould carbon fibre to such fine tolerances as required in the pistons and whatnot.
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Re: TECH TALK - ask your technical car questions

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titanium itself is not superlight, aluminium is alot lighter, Titanium is not as stiff as alloy is, it flexes more and for that it's a good material to use for springs, it's better for springs then steel because the spring action is smoother then that of steel.
And like said before there are more reason it's not usefull to use as a engine material, even if it where only the costs.
It's also used on exhaust systems on expensive cars like the McLaren F1, and even that is very expensive.

Carbon and other composites are used for a while now in combination with steel and alloys, by making Metal mmatrix composites. They are already used in engines and also in brakes, almost always in sportscars cause it's alot more expensive then normal metals.
but it's also used in other thinks like mountainbikes or other high end sports equipment.
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viper16 wrote:i thought aluminum warped with alot of heat.
Hence aluminuim alloy.
titanium itself is not superlight, aluminium is alot lighter
yeah, it's usually for components such as exhausts. Exhausts don't have to be super thick, unlike engine blocks, so titanium can be used here. It allows for thinner walls, and less material is used, hence the lighter weight. Titanium is not light...
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baumaxx1 wrote:yeah, it's usually for components such as exhausts. Exhausts don't have to be super thick, unlike engine blocks, so titanium can be used here. It allows for thinner walls, and less material is used, hence the lighter weight. Titanium is not light...
Yep, the lighter weight plus poor heat conductivity is ideal for an exhaust.
xHaZxMaTx wrote:I've heard of engines being made with carbon fibre (such as the Koenigseggs), but what components of the engine are those? I can't imagine being able to mould carbon fibre to such fine tolerances as required in the pistons and whatnot.
Carbon fibre can be used for the airbox, valve covers and timing belt covers, but I can't think of anywhere else you would put it. Carbon composite is different.
steelsnake00 wrote:The cylinder liners are steel, most of the time.
Manufacturers are starting to move away from that now. The technology is available to create a durable honed finish on the bare aluminium block, like the plasma spraying that was mentioned a while ago in another thread.


As for warping, all metals will warp when they get hot enough. The trick is to not let that happen.
Iron is harder to warp, but aluminium is easier to cool because it's a better conductor of heat.
Aluminium is also much easier to weld if it cracks.
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Re: TECH TALK - ask your technical car questions

Post by boganbusman »

Heh, I found this on another forum, figured I should post it here too :mrgreen: It's nice when you can explain difficult concepts with very few words.
Understeer is when you hit the wall with the front of the car and oversteer is when you hit the wall with the rear of the car.

Horsepower is how fast you hit the wall, torque is how far you take the wall with you.
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The understeer-oversteer thing was explained by Top Gear on its episode.



EDIT: Here is the video.

Ignore the animals. :lol:
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Re: TECH TALK - ask your technical car questions

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That is awesome. I've heard so many "what is understeer/oversteer/horsepower/torque" questions and I try to go into long explanations that just confuse people. I will definitely use that in the future. 8)
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Re: TECH TALK - ask your technical car questions

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Okay, I know it's possible to shift gears in a manual transmission without using the clutch (revving the engine to the right RPM at a certain speed), but what I don't know is if its damaging to any components of the drivetrain or if it's completely benign. Also, I don't really know, nor can I think, of any advantages to doing so - I just know it's a nifty trick. :P

It's pretty easy to do so in the Miata, in gears 1st through 4th, though I'm unable to shift up into 5th without using the clutch. :-k
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It won't damage anything if you have perfect timing. However if you repeatedly miss the shift then you will cause excessive wear/damage to the synchroniser assembly, as well as the dog teeth on the gear.

And there are no advantages, because you can shift faster by using the clutch. I've never tried to do it really, and I don't care to either. Remember that the clutch is a consumable, your gearbox is not :wink:
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Re: TECH TALK - ask your technical car questions

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boganbusman wrote:And there are no advantages, because you can shift faster by using the clutch. I've never tried to do it really, and I don't care to either. Remember that the clutch is a consumable, your gearbox is not :wink:
I learned to do it in case of ever having a clutch failure when a large distance from my destination. Cheaper to limp the car home than put the hazards on and have it towed 300 miles.
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Re: TECH TALK - ask your technical car questions

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It's rather uncommon for the clutch to suddenly fail, so I'll take my chances . . .
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I have done it through clutch failure in a manner of speaking. The Master cylinder on my MK1 broke and the fluid went on the floor while I was at work. Luckily it was only a short journey.
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Okay, here comes another retard question; Why are Ceramic Brakes so good? I've read in a few magazines that many "supercar manuafacturers" are putting ceramic brakes as an option (or standard) on their cars. What is the advantage, and how does the ceramic brakes achieve the advantage over regular brakes?
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Ceramics are very good at dissipating heat and have a very high heat-tolerance, so that the brakes cool down quickly, making them much less prone to brake fade. Not to mention ceramic discs significantly lighter than traditional iron discs.
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However, because they are designed to work at higher temperatures they tend to require vastly increased braking pressure from the driver when cold, and have very little in the way of pedal feel.
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