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Discussion: Ask those car questions you were always afraid to ask

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    Ask those car questions you were always afraid to ask

    Ok. We have a thread similar to this on another car forum, and think it’s a good idea.

    I don’t consider myself terribly knowledgeable in a technical perspective. Sometimes I have automotive or mechanical questions I can’t really find the answers to elsewhere, so I thought it might be a good idea to have a sort of ‘general automotive inquiry’ where anyone with answers can chime in. I often which I knew more about everything. It’s all in the spirit of learning, and knowledge is king. (ok, cash is king, but I don’t have that either…) At the same time, it can keep all questions in one big thread as opposed to having several small threads, and sometimes randomly reading through it, you might just learn something you never thought about asking.

    - Keep it automotive, motorcycle-related, or at least mechanical;
    - Keep it respectful (there are no stupid questions, dumb people think they know everything);
    - No drama llamas. You ask a question or you provide an answer, period;
    - ‘Google it.’ isn’t an answer;
    - Yes people should google their questions first, but this is more fun;
    - I hope there isn’t already a thread like this one, if so, oups.

    :::

    Bon, donc j’ai vu un fil de discussion similaire sur un autre forum d’autos et je crois que c’est une bonne idée.

    Je ne me considère pas comme très connaissant dans l’aspect technique de la mécanique. Je suis très curieux et parfois, j’ai des questions auxquelles je ne trouve pas toujours un réponse claire ailleurs, donc je crois que ça pourrait être une bonne idée d’avoir un genre de fil ouvert pour toute question que n’importe qui puisse y répondre. C’est tout dans l’esprit d’apprendre, et en même temps, on peut tout garder les questions dans un seul fil de discussion à la place d’entre avoir plusieurs petits. Parfois, simplement en lisant cette discussion, tu pourrais apprendre quelque chose sur lequel tu n’as jamais pensé y poser la question.

    - Gardons ça dans le domaine de l’automobile, la moto ou au moins en mécanique général applicable;
    - Dans le respects (il n’y a aucune question stupide, les stupides croient tout savoir);
    - Pas de drame s’il te plait. Tu poses une question ou tu réponds à une question;
    - ‘Google le’ n’est pas une réponse;
    - Oui, les gens devrait d’abord rechercher sur Google, mais ici c’est plus le fun;
    - J’espère qu’il n’existe pas déjà un fil de discussion comme celle-là, sinon oups.

    :::

    I’ll start.

    Why do manufacturers build naturally aspirated engines at a compression lower than the maximum allowable compression possible for a given fuel grade?

    Let me elaborate: Ferrari Testarossa with a 4.9L flat-12, compression ratio of 9.2:1

    Why? Still wanted to be run on regular? Even back then, premium unleaded fuels could handle 12.0:1, no? What would be the advantage of running such a low compression, especially on something like a Testarossa where there wasn't really much designed compromise to performance.

    Pics for clicks




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    Citation Envoyé par Snail Voir le message
    Why do manufacturers build naturally aspirated engines at a compression lower than the maximum allowable compression possible for a given fuel grade?

    Let me elaborate: Ferrari Testarossa with a 4.9L flat-12, compression ratio of 9.2:1

    Why? Still wanted to be run on regular? Even back then, premium unleaded fuels could handle 12.0:1, no? What would be the advantage of running such a low compression, especially on something like a Testarossa where there wasn't really much designed compromise to performance.
    -Reliability, you dont want to tune anything to run on the ragged edge of detonation on a mass produced vehicle, A Ferrari might not be "mass produced" like a Kia but still not a rare animal, they sold thousands of them.
    -Available octane in different countries, and fuel quality also makes up for alot of that. A good example of this is how many of us have gone to the US, filled up there and got better mileage on that tank? Less additives and useless crap. Better quality fuel.

    Back in the 90s, anything above 9.5 compression usually required premium(91+) to give an extra margin for detotanion and was considered a "premium" or "performance" engine.

    OEMs leave alot on the table in some cases.

    A good example from the 90s is the 240SX. Going with a standalone or a tune on the good ole 2.4L netted 30+ WHP. While other like the Hondas (D16, B16, B18) where already near what they could get OEM.
    You want to race with THAT?!?!?!?

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    Not technical related, not that i want to do it, but is putting yellow lamin-x on your headlights legal?
    Citation Envoyé par Gregster Voir le message
    Hang out with Gregster.. Buy classic cars. Hangout with PassatDub buy fancy hair products

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    Citation Envoyé par Red96EK Voir le message
    -Reliability, you dont want to tune anything to run on the ragged edge of detonation on a mass produced vehicle, A Ferrari might not be "mass produced" like a Kia but still not a rare animal, they sold thousands of them.
    -Available octane in different countries, and fuel quality also makes up for alot of that. A good example of this is how many of us have gone to the US, filled up there and got better mileage on that tank? Less additives and useless crap. Better quality fuel.

    Back in the 90s, anything above 9.5 compression usually required premium(91+) to give an extra margin for detotanion and was considered a "premium" or "performance" engine.

    OEMs leave alot on the table in some cases.

    A good example from the 90s is the 240SX. Going with a standalone or a tune on the good ole 2.4L netted 30+ WHP. While other like the Hondas (D16, B16, B18) where already near what they could get OEM.
    Interesting. That makes sense, except why would Nissan not crank up the compression just like Honda did? Wouldn't they be getting better fuel economy and power while still retaining the same real-world reliability Honda got?

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    Citation Envoyé par El pibe Voir le message
    Not technical related, not that i want to do it, but is putting yellow lamin-x on your headlights legal?
    nope
    Citation Envoyé par Royal-Motorsport Voir le message
    Talking about z's i had a teaser of what ScHyZo's z can do and damn

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    in this computer age, do you guys think car manufacturers have the ability to make cars fail "on purpose"?
    IHEARTENGLAND

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    Citation Envoyé par Snail Voir le message
    Interesting. That makes sense, except why would Nissan not crank up the compression just like Honda did? Wouldn't they be getting better fuel economy and power while still retaining the same real-world reliability Honda got?
    Oddly enough, the Nissan KA24 was a popular 4-cyl. truck engine back then... while the rest of the world got CA18DET and then the SR20DET, we got a crappy truck engine.

    Why retool and redo an engine when you can cheap out and just slap it in as-is...
    You want to race with THAT?!?!?!?

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    Citation Envoyé par El pibe Voir le message
    Not technical related, not that i want to do it, but is putting yellow lamin-x on your headlights legal?
    Not legal

    "The colour of the headlights must be checked at a road
    vehicle inspection agent by projecting the light beam
    onto a white screen. The light projected onto the screen
    must be white."

    Even those discolored, cloudy headlights are illegal.

    SAAQ Mechanical Inspection Guide
    https://tunerbattlegrounds.com/compe...52-jose-mendez Vote if you want to help a local, can vote daily. Thanks!

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    Citation Envoyé par Pri Voir le message
    in this computer age, do you guys think car manufacturers have the ability to make cars fail "on purpose"?
    I dont think anything electrical related can "fail on purpose" but in the last 15 years there definitely has been more parts that wear down faster on a engine in order to create more work/maintenance. The part in place is cheaper to manufacture/install and needs replacement sooner, win/win for them. Plastic timing chain guides on numerous motors are a good example of this.

    And then you have the newer cars moving to direct injection. Alot more expensive parts(high pressure pump, lines, injectors, etc...) and also will require cleaning on the intake valves eventually(more maintenance), all that for 1L/100kms maybe.

    In the end, the consumer lose and has to pay more.
    You want to race with THAT?!?!?!?

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    A higher compression street driven TR engine would probably need an engine out every 2'000km instead of 24'000km. Imagine how much worse their reputation would get

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    Citation Envoyé par boxcarracer Voir le message
    A higher compression street driven TR engine would probably need an engine out every 2'000km instead of 24'000km. Imagine how much worse their reputation would get
    hahahah damn, 24,000km??

    You really think upping the compression to about 12:1 would wear out items that much quicker? You might be right, but I'm just thinking of my Mazda3 with its 12.0:1 compression ratio (over seas, it's 13.0:1 because they have better fuels) Although manufacturing techniques certainly have improved over time, I strongly doubt it's better better built mechanically than a Testarossa.

    I'm thinking maybe the Ferrari had cooling problems and the compression would creep up during tracking?

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    With a direct injection engine, at what KM is it good to get the valves cleaned?
    Citation Envoyé par Gregster Voir le message
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    Citation Envoyé par El pibe Voir le message
    With a direct injection engine, at what KM is it good to get the valves cleaned?
    Depends... There is no real guidelines for this. Some people have needed it as soon as 50k kms, some around 100k kms. Regardless of brand.

    Short commutes and never beating on it seems to make things worst.
    You want to race with THAT?!?!?!?

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    Citation Envoyé par Red96EK Voir le message
    I dont think anything electrical related can "fail on purpose" but in the last 15 years there definitely has been more parts that wear down faster on a engine in order to create more work/maintenance. The part in place is cheaper to manufacture/install and needs replacement sooner, win/win for them. Plastic timing chain guides on numerous motors are a good example of this.

    And then you have the newer cars moving to direct injection. Alot more expensive parts(high pressure pump, lines, injectors, etc...) and also will require cleaning on the intake valves eventually(more maintenance), all that for 1L/100kms maybe.

    In the end, the consumer lose and has to pay more.
    But what about something like how apple slows down older phones to help battery life.

    Alot of new cars have wi-fi and bluetooth... u dont think manufacturers dont plant “bugs” to make electronics fail in purpose?
    IHEARTENGLAND

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    Citation Envoyé par Pri Voir le message
    But what about something like how apple slows down older phones to help battery life.

    Alot of new cars have wi-fi and bluetooth... u dont think manufacturers dont plant “bugs” to make electronics fail in purpose?
    Not legal thus apple getting slapped with a lawsuit, but then again dieselgate unfolded at VW who cheated on emissions for sometime. There is no company that engineer's failures in their designs, but the design tolerance margins are smaller now then they were in the past because QC and advanced manufacturing methods, with the volume of sales it's normal to have some failures that's why manufacturer warranties exists.

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    Citation Envoyé par El pibe Voir le message
    With a direct injection engine, at what KM is it good to get the valves cleaned?
    Bonne question ça.
    Cette année je me suis acheté ma SS avec D.I. et je me le demandais aussi. J'ai pas vraiment le gout de mettre une catch can non plus.
    Et qui fait ça dans la région métropolitaine et ça coute combien ?

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    Momentum le fait à Kirkland. Il me semble que c'est une histoire d'environ 400$. J'imagine que plus tu as de valves, plus c'est cher, mais c'est un ballpark.

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    A mon tour,
    j'ai un booster pack, tsé avec prise USB, lumière LED, compresseur,
    si je le laisse dans le char comme je fais toujours, même full charge,
    a -30c comme ils annoncent cette nuit, y peut tu geler comme une batterie ?

    Si oui mes voisins auront pas de boost demain lol

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    une bonne batterie d'auto en forme avec son plein voltage + ou - 12.60v ne gèlera pas à -30 même dans un banc de neige, en bas de 12 c'est autre chose

    beaucoup de booster pack on des batterie type AGM , je crois seulement que tu auras moins de cranking de disponible !

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    Citation Envoyé par bobby35 Voir le message
    une bonne batterie d'auto en forme avec son plein voltage + ou - 12.60v ne gèlera pas à -30 même dans un banc de neige, en bas de 12 c'est autre chose

    beaucoup de booster pack on des batterie type AGM , je crois seulement que tu auras moins de cranking de disponible !
    La seule chose à ne pas oublier, c`est de 1 fois au 1-2 mois, de s'assurer de remettre une pleine charge sur la batterie si on veut que elle dure longtemps!

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