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dwightlooi

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dwightlooi last won the day on March 22

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550 Kind of a Big Deal

About dwightlooi

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    OSV Member
  • Birthday 09/10/1973

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    Belmont, CA
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    Cars, guns, technology, design, politics, cooking, etc.

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  1. Cadillac is lost on styling. Their new stuff looks "Mazda Inspired". But, they have also shown a lot of inconsistencies and indecision, hence who knows if the next vehicle will go back to the previous gen cues, stay the course or go in a totally new direction.
  2. (1) Valve and spark arrangement in modern Hemi pushrod cylinder head. (2) Flat Deck 6.6 Duramax turbo-diesel pushrod cylinder head. (3) Rocker and bridge arrangement on 6.6 Duramax turbo-diesel engine (4) Junkers-Jumo 213A engine showing off -- Direct Injection, Twin Spark, 2-intake / 1-exhaust valves per cylinder and a variable drive ratio supercharger (hydraulically coupled)
  3. Splayed or not, one rocket actuating one valve is no problem regardless of how the valves are oriented. But if you use a bridge to open both valves, they have to be parallel and the rod/rocket has to be perpendicular to the bridge. Otherwise as the rocker depresses it'll skew to one side of the bridge and open one valve more than the other -- like stepping on one side of a see-saw. The Hemi head is generally taken to mean ANY two valve head design where the intake valve is on one side and the exhaust valve is on the other side. This is irrespective of whether the roof is actually a dome or more of an oval. All the modern ones are oval allowing the flat decks on the sides to form a squish deck with the top of the piston to allow higher compression ratios. Twin sparks are very common with two valve and three valve designs -- OHC or Pushrod. If you want a REALLY HISTORIC example, go Google Junkers-Jumo 213A. That is a Supercharged 35 liter SOHC 36v inverted V12 cylinder engine used in the late WWII Focke-Wulf 190-D9 fighter -- it features three valves per cylinder, twin sparks and Bosch Direct Gasoline injection to generate 1,750hp @ 3,250 rpm (2,100 hp with 50% Methanol-Water injection in emergencies).
  4. Actually, no. Not really. You cannot have four push rods per cylinder and still have room for the intake runner to reach both intake valves. The Chrysler Hemi design simply allow for the intake and exhaust valves to be opposed instead of side-by-side. The purpose of that being the theory that two opposed valves and a hemispherical combustion chamber is more knock resistant and hence capable of higher compression and output than the heart shaped combustion chamber with side-by-side valves. However, with the current generation of Hemi vs non-Hemi V8 engines, this theory does not seem to yield real world performance superiority.
  5. Simple Answer: Yes it CAN. The Duramax 6.6 Turbodiesel in the current generation and previous generations are a Pushrod 32-valve V8. Complex Answer: The push-rods go from a cam in the valley of the vee to the inner side of the cylinder heads. These obstruct where the intake passages in an OHC engine would normally be. The intake passages hence goes around the pushrods offset to the right or left of the cylinders in the space not obstructed by the rods (and their channels). There is barely enough space to serve ONE intake valve per cylinder. If you put four pushrods in an engine you'll obstruct all the approaches to the cylinder from the intake side! Doesn't do you any good to have increased valve areas if you squeeze out the intake ports and runners does it? So how does the diesel 6.6 do it? Well, it still has two rods per cylinder. Each operate two tandem valves using a bridge between the valves. The inner and out valves on the left are both intake and the inner and outer valves on the right are both exhaust. This is possible because the roof of the head is flat and all the valve stems are parallel, allow one rocker to open both valves via the bridge. It is meaningful because it is a DIESEL engine and it doesn't rev past the mid-3000 rpms anyway so one single intake and one sn=ingle exhaust passage is enough to not be the airflow bottleneck. Had it been a pentroof combustion chamber like that found on gasoline engines, the bridge design would be impossible and having a single passage serve two valves would have defeated the intent of using more valves to increase the airflow potential at high rpms.
  6. The thing is that you can have a Hybrid with 30~50 mile electric range (12~20kWH battery) or you can have a pure electric with 200~300 mile range. They'll weigh about the same. That additional 60kWH in battery capacity is going to cost you about 700 lbs in vehicle weight. If you'll like an ICE it is going to cost you about 700 lbs too for the engine, cooling system and transmission. If you want both, be prepared for a 5,500~6,000 lbs car (The model S is already 4,900 lbs).
  7. Tesla quality -- interior wise -- has NEVER been at the level of a luxury car much less a $100K luxury car. In fact, Hyundai puts them to same.
  8. Type S = Type SUCK Extra money for a lousier ride in a car that goes no faster.
  9. LOL... a great American... uh... Canadian... novel worth of posts later it comes down to this. Oldhurst442 lives in Canada and is worried about corrosion in used cars. Because of import laws, he doesn't have access to cars from south of the border. Doesn't change the fact that a certified 3 year old will have ZERO CORROSION and ZERO ACCIDENTS or it could not have been certified. BTW, I am sure canada has no restrictions of Quebec folks buying cars from British Columbia.
  10. There is this thing called SHIPPING. It costs $400~600 to ship a car to Northern CA from Southern CA, AZ or NV. About $800~1000 to ship it from the mid-west including Texas. About $1300 from the east coast including Florida. The last two cars I bought, I bought online sight unseen and have them shipped. With the exhorbitant rent and labor costs, buying from local dealers adds about $3000~6000 to the price of a $40K used car. So I buy out of state and pay a few hundred bucks to get it shipped in. If you are so fussy about salt and snow you can get yours remotely too.
  11. I got the 2014 CTS VSport Premium from Texas with 26K miles and not a scratch in 2017 for $33K ($40K off the $73K as new price tag). That's 55% off. You cannot convince me that buying new and driving that first 26K miles at a cost of $40K is a good deal compared to driving the next 70K miles for $18~20K. It has 69K miles on it now and I'll probably keep it for another year to year and a half.
  12. The beautiful thing about the market place is that we do not have to rely on oldhurst442 for a healthy supply of used cars. I have never, ever, had a significant issue with my used cars. I buy at 3~4 sell at 6~7. Usually, they never see the inside of a workshop and if they did it is usually under warranty anyway. I don't even buy particularly "reliable" makes and models (apart from the two Acuras). The last 6 were 2017 Acura MDX, 2014 CTS VSport, 2011 Jaguar XF 5.0 Supercharged, 2008 Acura TL, 2005 M-B C55 AMG and 2000 Audi S4.
  13. Go buy a new car and lose lots of money then. It's a free country -- even Canada is in this regard. We need people like you to buy new so we have used cars to benefit from. I'll never buy new. If I have a billion dollars, that 2014 Boeing 787-9 with 20,000 flight hours will look pretty good especially if it has GEnx engines that was just overhauled.

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