Parasitic Loss

Discussion in 'High Tech for Old Iron' started by Briz, Aug 11, 2017.

  1. Stevem

    Stevem Well-Known Member

    Some folks spend a lot of money to loose HP when they fight to run only 180 degrees or even worse yet 160 degrees of coolant temp!
    The big oval track guys run 200 degrees coolant temp or more because heat is power and the internal combustion engine runs on hot expanding Gases!
    Just look at the break down of it.

    20% of all the heat generated gets radiated off the motor.
    20% gets dumped into the cooling system.
    25% goes out the Exh.
    35% is left to spin the flywheel!

    Gee , Turbo charging looks like a great thing, no? Lol!
    300sbb_overkill likes this.
  2. 300sbb_overkill

    300sbb_overkill WWG1WGA. MAGA

    I agree, especially with the cat pee they call gasoline nowadays, that stuff likes to be hot before burns! I think it likes to be vaporized before it burns to get a more complete burn.

    So yeah, if in Briz is running high octane fuel anyway he may be able to raise the coolant temp and pick up a bit more power if the air charge doesn't get hotter doing it and the engine stays out of detonation? Get a knock alert sensor if you try this.

    My little turd car an '02 Sunfire gets better gas mileage with the A/C running and the engine running hot than it gets at the factory 195*F where its set to run, its like 10% more so not to shabby! The temp creeps up at a stop light with the A/C on while the inside of the car also gets warmer at the light.

    Need to check and see if the other fan is coming on when the A/C is switched on, probably won't check it because of the 10% more fuel economy it gets when hotter though.:cool: I don't hear any pinging so chicken in a bucket(eff it).

    Would love to run high static compression with a relitively mild cam, but the octane needed to do that is just not affordably available! With a slightly raised compression street engine with the at the pump fuel available today 180* is a good compromise to help stay out of detonation.

    The aftermarket needs to come out with direct injection for the old engines! IIRC they claim 30% more power and fuel economy with D/I, imagine a BBB with it! Able to run at 200* @ 12:1 compression with cast iron heads and a mild cam without detonation!!!

    A roller cammed BBB with cast iron heads that only flow say 260 cfm @ .500" lift intake and around 170 ex. say same lift and a cam with .560" in. and ex. with a 1.6:1 rocker ratio, 114* LSA and 226* in. 238* ex. a relitively mild cam. The 12:1 compression would raise the low end torque tremendously with a cam like that with decent HP maxing out at a lower RPM because of smaller cam so it doesn't need to be revved the snot out of it to get to the max HP.

    (Just a side note, the heads would probably need to be made new with the direct injector able to be installed in it so the new heads would more than likely be aluminum, don't think a factory head would be easily converted to D/I.)

    Taking advantage of over lifting the cam past the max flow so it flows max after it hits .500" all the way over the nose and back to .500" lift to fill the combustion chamber more effiently, without the D/I the engine should be around 500 HP with around 550 ft lbs with race gas, add the D/I and its goes up 30% to around 650 HP and over 700 ft lbs of torque and using just 87 octane pump gas!! Throw a 200R4 overdrive behind it with a 3.08:1 rear gear it should make enough low end torque not to lug the engine in O/D @ 45 mph! The fuel economy would be 30% better as well, possibly 28 mpg w/od or possibly more if the higher compression is factored in?

    Now take the above engine and throw some boost at it, a jock strapped(girdled) factory block would be blown to pieces starting with 650 HP before boost and all with running 87 octane with the coolant temp @ 200 without detonation with both examples!!

    Why isn't anyone trying to make direct injection for the older engines?!!! As good as a new car's fuel economy and way better performance to boot!! Can't wait!
    Last edited: Aug 21, 2017
  3. Briz

    Briz Platinum Level Contributor

    She's @ 13-1 compression running 110. Went through about 5 gals Sat night. Have a custom ground solid roller cam purchased used at BG swap meet a few yrs ago. Think the card said it was like 660 lift. added 1.71 roller rockers. Had to butterfly cut the domed Aries pistons more to accommodate the valve travel.
    Really not looking to gain much more power just want what I got to be consistent and it seems to be doing that based on the time slips. Weather is always a ever changing factor in trying to figure out a dial in.
    300sbb_overkill likes this.
  4. 8ad-f85

    8ad-f85 Well-Known Member

    In the interest of parasitic loss and discussions about compression and heat...
    You can see way more than 28 mpg on engines that size at 7:1 but there's enough heat in the chamber to run the ragged edge of detonation.
    I suppose the explanation is partly to reducing pumping losses.
    No need for all that fancy busy-ness of DI.
    The engine doesn't care how the fuel is vaporized.
  5. 300sbb_overkill

    300sbb_overkill WWG1WGA. MAGA

    Have you ever considered getting one of those mini weather stations to see if you can make a cross reference guide to make a closer guess to your dial in time?

    Never used one so I can't give any advise for them. There might even be a smart phone app. that does the same thing in real time? I doubt the location would be at the track though?

    Here are a few;"weather%20stations"&kr=weather%20station
    8ad-f85 likes this.
  6. Briz

    Briz Platinum Level Contributor

    Had an app on my phone a few years ago that was supposed to do exactly that. You entered the info from the time slip into the app. It would connect with a local weather reporting station and then based on the info provided would make a prediction on the next runs ET. However during the time my engine was down it developed a glitch where it would no longer connect to any weather reporting sources.and the maker has not yet come up with a fix.
  7. 300sbb_overkill

    300sbb_overkill WWG1WGA. MAGA

    Thats what I thought about a phone app.

    This is what the first weather station in the link says it can do;

    "Altronics PerformAIRE weather stations are motorsports' most accurate and only patented air-quality computers. They monitor temperature, absolute barometric pressure, and relative humidity through their state-of-the-art electronic sensors. This information is transmitted into a microprocessor, where density, altitude, and predicted values are calculated and displayed. They offer incredible accuracy through exact scientific equations, formulated specifically for internal combustion engines."

    Even if its not as accurate as they say as long as it repeats it should be a very useful tool. The weather stations in the link don't depend on remote weather stations to relay what the weather is somewhere else, they're supposed to measure the weather where you're at in real time.

    If you get one let us know how you like it.
    Briz likes this.

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