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dwightlooi

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  1. dwightlooi

    DIY Engine Start/Stop workaround

    Background Many cars now come equipped with Start/Stop. Many consumers hate having their engines turn off automatically at a stop light and coming back on when they release the brake pedal. They hate it because it reduces the life of the starter, degrades the battery, may increase wear on the engine and REDUCES REFINEMENT of their vehicles -- having the motor shudder to a stop and shuddering to life repeatedly is decidedly less refined than a smooth imperceptible idle. They hate it because it saves an imperceptible amount of fuel in most driving conditions. Most manufacturers equip cars with a Start/Stop disable button (except in atrocious cases like the 2017 Terrain which doesn't even have one). But, in order to have very slightly better EPA MPG numbers, they usually make the buttons "non-latching". That is, you can manually turn Start/Stop OFF but every time you start the car it reverts to ON. They do this so that the vehicle's MPG and CAFE numbers are calculated with Start/Stop ON. Had the button been "latching", it'll be calculated as the average between when it is OFF and when it is ON. Myopically, manufacturers almost universally choose very marginally better EPA fuel economy ratings (~0.1 mpg), and kissing up to environmental extremists in government, over customer satisfaction. Solution There are several commercial aftermarket solutions to defeat Start/Stop. But, for people who want to do it yourself, here's a solution which turns start stop off every time you start the car. This solution works with ANY car with a start/stop button, and it fully retains the functionality of the start stop button. (1) First, you need to go buy yourself a timer relay. It'll cost you about $17 and you can get one here (not affiliated to me but it's a product that works):- https://www.amazon.com/Timer-Delay-Relay-Hours-Cycling/dp/B00PD65UGA (2) Secondly, you need to find the wires that go to the START/STOP button. It'll be the wires that shows a closed circuit when you push the switch (and only when you push the switch). (3) Find your fuse box. There should be a terminal which is ON (only) when the car is running and OFF when the car is not running. Find it, and use that to power your Timer Relay so that it gets power (only) when the car has been started; it doesn't get power when the car is off. (4) Read the instruction manual and program your Timer Relay. Mode#7 -- Delayed Interval (Single Cycle) -- if you are using the relay I linked to DELAY (t1) 3 sec INTERVAL (t2) 1 sec (5) Wire your Timer Relay to where your Start/Stop Switch harness plugs into the vehicle's electrical system or splice into the switch's wires -- it makes no difference functionally. Once you have done the above the following will happen every time you start the car:- Timer Relay receives power Timer Relay waits 3 secs (t1) Timer Relay presses the Start/Stop Button for you and holds it for 1 sec(t2) Timer Relay releases the Start/Stop button Timer Relay does nothing for the remainder of the duration the car is running. Basically, the Start/Stop Button is getting pressed and released automatically 3 secs after you start the car, turning start/stop off. If you want to use start/stop, you can hit the button to turn it back on. The button continues to work to turn start/stop off or on as much as you like; the relay simply presses it once every time you start the car so you don't have to. Viola!
  2. dwightlooi

    Return of the 2-Stroke Engine

    NVH should be no better or worse I guess... Maximum engine speed will be worse though. It'll be worse because the pistons are heavier (longer skirt needed to cover the exhaust ports), and also because you no longer have a dedicated exhaust stroke (at high speeds there will be less time for the intake air to push the exhaust out). This is why through flow side port engines -- including the Opposed Piston designs like the Fairbanks-Morse 38D8 1/2, Junkers Jumo 205 and more recently the Archates stuff -- tend to be diesels which do not rev that high anyway. It should be manageable up to 5000~6000 rpm or so using a rising rate supercharger (like a centrifugal blower). This is never going to be an Honda F20C, that's for sure.
  3. dwightlooi

    Return of the 2-Stroke Engine

    The original illustration was removed for some reason. Here it is again.
  4. dwightlooi

    Why Bi-Turbo V6es ALWAYS suck.

    LOL... It sits in a terrible location that is unreachable, unserviceable and very far from the exhaust ports! Basically, it's behind the engine, below intercooler and above the transmission. VERY long pipes connect the turbo to the exhaust ports below the engine. If you straighten out the pipes the turbo is about as far from the engine as the front seats in a car. For emissions purposes, Subaru even stuck a small catalytic converter between the exhaust ports ahead of turbo for the further pair of cylinders. Another main catalyst is, of course, located after the turbo. It all amounts to a mess that is both inefficient and a nightmare to work on. Also, with the intercooler above the turbo and fed by a hood scoop, when the car is stationary, all the heat rises up to heat soak the Intercooler. Congratulations! BTW, if that pre-cat breaks all that debris goes turbine...LOL! (See photos) That is why all the STi WRXes always have inferior turbo response compared to the Inline-4 Lancer Evolution. It takes 4,000 rpm for the STi to make full boost and it is rather placid 14.7 psi.
  5. dwightlooi

    Why Bi-Turbo V6es ALWAYS suck.

    Nope, but they should for a mid-engine sports car. I think ford wasted a good opportunity with the Ecoboost V6 Ford GT. These have a lot of height in the engine bay if you don't mind seeing the engine in the rear window. The Audi R18 Le Mans race car is a hot vee single turbo 3.7L V6. But that is (oddly enough) a DIESEL Le Mans race car, and that doesn't constitute a "production" engine. The C8 is unlikely to use a hot vee single setup since it is a V8 and that is as good as an I4 which is good enough.
  6. dwightlooi

    Why Bi-Turbo V6es ALWAYS suck.

    As explained in the original post, a Hot Vee SINGLE TURBO design will provide uninterrupted exhaust flow to the turbine. A twin-scroll turbine housing will be preferred for intake breathing efficiency. Hot Vee Singles are rare because the exhaust collector bridging both sides and a single larger turbo means the turbo sits really high and interferes with the desired hood line. It has been done though... the Duramax 6.6 is an example of a Hot Vee Single Turbo. It makes 445 hp @ 2,800 rpm and 910 lb-ft @ 1,600 rpm (it's a diesel). Note: Notice how tall the entire turbo setup is and why it may be a problem in a sports car or a sedan. However, a Hot Vee Twin Turbo design like Mercedes' M276 DELA30 (3.0L Twin Turbo; C400/C450/C43 AMG) provides no advantage apart from packaging (which is itself debatable). I find Mercedes' coining of the term "Pulse turbocharging" ironically laughable as it describes the interrupted exhaust problem of V6 bi-turbos so succintly. IMHO, conventional flanking turbos can be located just as close to the exhaust ports as a turbos in a Hot Vee, and flanking turbo designs like GM's LGW (3.0L Twin-Turbo; CT6) performs just as well.
  7. dwightlooi

    Why Bi-Turbo V6es ALWAYS suck.

    That is what they claim. Ask yourself two things. Firstly, how much of that is due to Multiair itself and how much of that is due to everything else Fiat put in the engine -- say Direct Injection or using tiny displacement engines (like their 1.4L). Secondly, how does cutting off the action of the intake valves partway through the cycle accomplish all those things better than VVL systems that... well... offer long and shorter duration valve actuation with advance and retard of the timing?
  8. dwightlooi

    Why Bi-Turbo V6es ALWAYS suck.

    Oh, there is plenty of restriction. Whether you are choking the engine with a throttle plate or by reducing the intake valve openings, you are choking the engine. If that is not the case, you'll have unintended acceleration ,which will be very bad! The only time there is no restriction is in a Diesel Engine. In a Diesel Engine, there is no throttle and the valves always open fully. The engine simply injects more or less fuel to make more or less power. This is half the reason why diesels are so efficient -- you are never choking the diesel engine. But, it runs very lean when you drive gently and running very lean makes a lot of Oxides of Nitrogen which -- unlike Carbon Dioxide -- is actually bad for the air. This is why you have nitrogen storing catalysts on modern diesels. Because these cats get poisoned by sulfur, that is also why low sulfur gasoline is a must for some of these diesels. Or, you can inject piss into the engine -- Mercedes Benz's Bluetec is simply a nicer name for Urea Injection. What Multiair and Valvetronic (not VANOS) do are that they eliminate the vacuumed space between the throttle and the intake ports. This makes throttle response technically superior as there is no plenum to bring up from vacuum to atmospheric pressure. I am not sure it makes the engine more efficient although the engine holistically might be for a host of other reasons.
  9. dwightlooi

    Why Bi-Turbo V6es ALWAYS suck.

    And, the reason is simple... When you open the throttle, the naturally aspirated motor has to fill the volume between the throttle body and the intake valves -- aka the plenum -- from vacuum to atmospheric pressure. This is normally very fast. It can actually be faster than the throttle plates can move if you have the throttle plate(s) mounted at the intake port. Remember the the S65 4.0L M3 engine with the individual throttles in the velocity stacks for each cylinder? Or, heck, remember the individual side-draft carburetors on the intake ports of motorcycle engines? The Turbocharged engine has to first do the same thing and fill up the volume to atmospheric pressure, make exhaust energy, spin up the turbines to spin the compressor, start increasing that volume to the working boost pressure. That takes significantly longer. To make matters worse, the volume between compressor and the intake ports is also a lot more voluminous on a turbocharged engine. It usually goes from one side of the engine to the other and includes additional volumes like the intercooler.
  10. dwightlooi

    Why Bi-Turbo V6es ALWAYS suck.

    You must not be very good at noticing then! Even on the VW-Audi 1.8T (circa 2000) where the turbo is making a paltry 7~8 psi (very low by today's standard) you'll notice it. You'll notice it particularly during part throttle application. You put in 70% throttle and it feels like the throttle takes 2 seconds to roll from 30% to 70%. Even in a laggy engine, full throttle lag is never an issue because you know its there and you know the power coming. The problem with handling a turbocharged car through the corner is that when you apply part throttle mid corner it is as if you are working the throttle via a rubberband. It is non-linear and it is difficult to control. Instead of applying the throttle you need and rolling on more as you straighten out the wheels, you must apply the throttle eventually want a second or two ahead and time the torque rise match your corner exit. In a way, it's like doing differential equations while driving. In any case, if you have a V6 you are not getting a twin scroll.
  11. dwightlooi

    Why Bi-Turbo V6es ALWAYS suck.

    You do know that this is physically impossible, right? Turbos will have lag, period. Why? Because they build boost by pumping more air than the engine ingests and building up positive pressure. It takes time to go from vacuum to 15 or 20 or 25 psi just like it takes time to fill up a balloon. It is impossible to do that immediately just like it is impossible to make boost by revving your engine in neutral (where the unloaded engine can rev up faster than the turbos can move air into the manifold). Twin Scroll turbine housings do not eliminate lag they are there to solve an intake problem. You see, in a 4-cylinder engine when the exhaust valves on a cylinder opens towards the end of the power stroke, another cylinder still has its exhaust valve open towards the end of its exhaust stroke. To make matters worse, that cylinder also has its intake valves opening as the end of the exhaust period overlaps with the intake period. This means that the high pressure exhaust gases exiting the cylinder at the end of the power stroke will push into the cylinder ending its exhaust stroke and beginning its intake stroke. This hammers intake aspiration as well as rob the turbo of exhaust pressure that otherwise would be applied towards spinning the turbine! There are two solutions to this problem. The first is to have essentially no intake/exhaust overlap -- most traditional turbocharged engines do this. But, this means the engine won't breathe right above about 5000 rpm and it negates whatever advantage you might gain from a DOHC 4-valve head. The second is to segregate the exhaust flows from cylinders 1 & 4 and that of cylinders 2 & 3 -- that's a twin scroll, twin volute or simply divided turbine housing. You never see twin scroll turbos in bi-turbo V6 engines or inline 3 engines because it is unnecessary and USELESS -- exhaust periods on a 3-cylinder or a V6 bank do not overlap!
  12. dwightlooi

    Why Bi-Turbo V6es ALWAYS suck.

    It is an issue they pay a price to deal with. A price in smaller cabins. A price in a heavier engine. A price in a heavier car with unnecessarily long wheelbases. As far as the M256, that is an S-Class only engine for now and not even on US bound S-Classes. Looking at the C-Class engine bay it may take a platform change to fit it in the C-Class. Well, the C8 has a big displacement, Naturally Aspirated, Pushrod V8 for you with 500 hp (give or take)! And, it is probably the cheapest engine on offer. Expect at least 17/30 mpg (already achieved on the LT1 with AFM on) from it which is no worse than anything else making 500 hp either.
  13. dwightlooi

    Why Bi-Turbo V6es ALWAYS suck.

    Yes, and a supercharger has (practically) zero lag too. But that is not the point of this thread. The point is that a V6 bi-turbo is architecturally inferior to other turbocharged arrangements. Displacement or not, you'll have the same problems turbocharging a 4.7L V6 as you'll have a 1.8L V6.
  14. dwightlooi

    Why Bi-Turbo V6es ALWAYS suck.

    It is if you want to keep the entire engine behind the front axle for balance purposes... You'll either have to have a very long hood and wasted wheelbase length (which does not go towards a roomier cabin), or you'll have to stick the engine past the front axle and have sub-optimal balance. It is significant enough for Nissan to abandon the 2.6 RB26DETT for the 3.8 VR39DETT.
  15. LOL... I think you'll "like" the Lexus RX350L Hybrid 3rd Row. The top of the seat cushion is about 4 inches from the floor (which is higher than the regular RX350L due to the battery). You seat with your legs up like an "A".

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  • Gender
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  • Location
    Belmont, CA
  • Interests
    Cars, guns, technology, design, politics, cooking, etc.


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