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Bore and stroke for reliability?

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TrackpadUser

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Post Sun Feb 15, 2015 4:56 am

Re: Bore and stroke for reliability?

When you take part in a tournament from the challenge and competitions sub-forum, you usually end up having to balance performance and costs. And quite frankly in most tournaments, if you use no quality everywhere you will get wrecked.

If you ask me, I don't see what is fun to put all sliders at +15 all the time, but putting some of them at +5/+6 depending on the situation can wield good results w/o raising the price too much. You just have to think about what would make sense in your situation, and it doesn't take that much to make a big difference on the performance, notably when it comes to the top end.

So yeah, while having a ton of quality on a cheapo econobox doesn't make much sense, bringing the sliders up a little on a sportier or luxurier car does make sense. Back when I made econobox engines they rarely had quality, except maybe +1/2 on the top end for the engine made to be used in a hot hatch.
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BurningBridges

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Post Sun Feb 15, 2015 6:27 am

Re: Bore and stroke for reliability?

I think game quality will play a role in the game, and in the sandbox, and a small quality boost may not drive the price to astronomical heights. But to me it's not interesting from a engineering and industrial perspective to produce over-expensive cars. Or on other words, everyone who can design a great, inexpensive car can also make an expensive one, but not vice versa. A car that costs 10 times as much would be much harder to succeed in the market, so in the end the most affordable will win, or those with a special prestige. There are examples but they did not succeed because they invested lots of money, but because they had special skill. For example the Italians around Modena have an antique craftsman tradition that is hard to repdoduce in other parts of the world, especially in the mass produced American market. So it was less a question of money, but of people.
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autofrank

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Post Mon Feb 16, 2015 4:04 am

Re: Bore and stroke for reliability?

Also, smaller engines are more reliable than larger ones in the early stages. More size means more mass and therefore more strain on engine components. 300ci and larger will suffer more reliability at higher RPM - so adjust the quality scale up to get better results for now.
Personally I'd like to see manhours and MTBF return rather than production units and reliability score of 0-100.
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Jakgoe

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Post Mon Feb 16, 2015 8:30 am

Re: Bore and stroke for reliability?

autofrank wrote:Also, smaller engines are more reliable than larger ones in the early stages. More size means more mass and therefore more strain on engine components. 300ci and larger will suffer more reliability at higher RPM - so adjust the quality scale up to get better results for now.

Smaller engines are generally more reliable overall. In the early game years, the 40s and 50s, you do not have access to many parts, and this is especially noticeable on the bottom end. You have to compensate by A) Decreasing engine size, B) Making the engine massively oversquare, or C) Lowering the RPM limit.
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Post Mon Feb 16, 2015 8:59 am

Re: Bore and stroke for reliability?

I usually play from 1960 to 1980 and all my engines are currently 1:1 to 1:1.1.
I have a simple technique to find a good right bore / stroke. I usually adjust the stroke until it matches the rpm (the rpm depends on the CAM profile I want to use, usually 70). I just move it to the point where the reiliability starts to decrease. That becomes the rpm limit.
With the bore you have more flexibility, depending on the displacement you want. I adjust it after the stroke so that it matches my rpm range and until I get the best hp/kg.
The later the year, the longer stroke becomes feasible, and more hp/kg.
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TurboJ

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Post Wed Jul 22, 2015 12:10 am

Re: Bore and stroke for reliability?

It's an old thread, but I have noticed something interesting about engine reliability.

If you use both block and head of cast iron, your will have better reliability than an iron block with an alloy head. Also both made of aluminum will result in better reliability.

I don't find this very realistic. The most popular way of building an engine between '60s and '00s has been iron block + alloy head. Some of the most reliable/durable engines
of all time have been built like this - such as the Mercedes OM600-series, Saab H-engine and the Audi 5-cylinder. So I think this should be changed so that the material itself
has a reliability coefficient, but not the combination of materials.
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Sayonara

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Post Wed Jul 22, 2015 12:31 am

Re: Bore and stroke for reliability?

The earliest aluminium head + iron block engines did have issues, generally in the way of head gasket failures due to the differential expansion rates of iron and aluminium.

It hasn't been a problem for a long time, so I'd say that the actual problem is that the reliability penalty is too high, especially in the 90's-00's period.
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TurboJ

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Post Wed Jul 22, 2015 12:48 am

Re: Bore and stroke for reliability?

Yeah, that would make sense.
The penalty should be negligible in the later years but I do agree the first developments could have a more noticeable penalty.
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Post Wed Aug 26, 2015 6:22 pm

Re: Bore and stroke for reliability?

Sayonara wrote:It hasn't been a problem for a long time, so I'd say that the actual problem is that the reliability penalty is too high, especially in the 90's-00's period.


I agree with this. There were lots of problems in the 80's but in the 90's aluminum heads on cast iron blocks were common and Honda revved them to the moon. The head gaskets never leaked, unlike the 80's Dodge Daytona which had horrendous head gasket issues.
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Post Fri Aug 28, 2015 6:42 am

Re: Bore and stroke for reliability?

Any word on whether or not the devs will make an adjustment to this?

I'd really like to build some motors with differing metals, like basically every real life car maker does, but the reliability penalties are just too severe, and that's not fun (or, again, realistic).
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Trifler

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Post Fri Aug 28, 2015 10:59 am

Re: Bore and stroke for reliability?

Another thing is that at the moment, even when you can mix metals reliably, it strongly encourages you to do the opposite: to use an aluminum block and a cast iron head. This is because it gives a small horsepower bonus for a cast iron head, and the vast majority of the weight and emissions reductions come from the block. I'm not saying this isn't realistic, but it makes me wonder why so many auto makers chose to go with cast iron blocks and aluminum heads then.
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Post Fri Aug 28, 2015 12:32 pm

Re: Bore and stroke for reliability?

Trifler wrote:Another thing is that at the moment, even when you can mix metals reliably, it strongly encourages you to do the opposite: to use an aluminum block and a cast iron head. This is because it gives a small horsepower bonus for a cast iron head, and the vast majority of the weight and emissions reductions come from the block. I'm not saying this isn't realistic, but it makes me wonder why so many auto makers chose to go with cast iron blocks and aluminum heads then.


Cost.
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Trifler

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Post Fri Aug 28, 2015 1:03 pm

Re: Bore and stroke for reliability?

Slim Jim wrote:
Trifler wrote:Another thing is that at the moment, even when you can mix metals reliably, it strongly encourages you to do the opposite: to use an aluminum block and a cast iron head. This is because it gives a small horsepower bonus for a cast iron head, and the vast majority of the weight and emissions reductions come from the block. I'm not saying this isn't realistic, but it makes me wonder why so many auto makers chose to go with cast iron blocks and aluminum heads then.


Cost.


Not a good enough reason IMO considering they (mostly) only did it on the cars with small engines.
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Slim Jim

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Post Fri Aug 28, 2015 3:01 pm

Re: Bore and stroke for reliability?

Ok... how about iron block for strength, and aluminum head for weight savings? :P Of course, I'm just speculating... it is an interesting question though.
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Trifler

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Post Fri Aug 28, 2015 3:19 pm

Re: Bore and stroke for reliability?

Slim Jim wrote:Ok... how about iron block for strength, and aluminum head for weight savings? :P Of course, I'm just speculating... it is an interesting question though.


:)
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