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Thread: Poor Performance When Hot

  1. #31
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    Quote Originally Posted by markm View Post
    I don't recall the fuel Tony runs, but to run good in heat you must run a good quality race fuel with a 10-1 BBC.
    Is that to prevent detonation or some other reason? I don't have any detonation. I'm running pump gas 93 octane.
    Tony

    1955 Bel Air Sport Coupe

  2. #32
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    Tony

    1955 Bel Air Sport Coupe

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  4. #34
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    Quote Originally Posted by 55 Tony View Post
    Is that to prevent detonation or some other reason? I don't have any detonation. I'm running pump gas 93 octane.
    How do you know for sure and there is more to it than that. Not going to go into details because some on here love to jump on my shit if I don't get it perfect. There is a lot of consistence to be gained with good fuel.
    Last edited by markm; 06-14-2018 at 11:09 AM.

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    I'm pretty good at hearing a knock or ping, my exhaust is not loud enough to cover up the sound. But since I think a few mentioned it, I'll try turning my timing back 2°. Actually I've been busy but I want to check the timing cold, then check it again when real hot. With an electronics background I doubt a faulty MSD dizzy could advance the timing, but it could retard it. I'm grasping at straws but that is a constant with other things changed over time.
    Tony

    1955 Bel Air Sport Coupe

  6. #36
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    Quote Originally Posted by markm View Post
    Not going to go into details because some on here love to jump on my shit if I don't get it perfect. There is a lot of consistence to be gained with good fuel.
    What??? Here???
    Tony

    1955 Bel Air Sport Coupe

  7. #37
    Registered Member chasracer's Avatar
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    Wow- Anytime you heat up the surrounding air around an engine, it is going to have some effect on the performance of that engine. The engine's ability to shed temperature is not strictly related to coolant temperature as you appear to believe. Oil temperatures, exhaust heat and coatings, air flow around the engine all contribute to the engine's ability to shed heat.

    As to the alcohol comment, I have to hand it to you - I busted out laughing at your remark. Methanol fuel has an extreme affect on the temperature and performance of our engines. On racing fuel with adequate octane to support our compression ratios, we would have the same cooling issues to deal with that Tony is talking about but running Methanol, I can hot lap any of our cars 7,8,10 shots, doesn't matter, by the time we complete the run and get back to the lanes, our engine temperatures have dropped to 155 or so just due to the fuel.

    And again if you really raced you would understand why Pro Stocks, Comp. Eliminator cars and others go through the process of chilling their engines. A cooler engine at the starting line is going to net you a better ET and MPH - each and every time.
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  8. #38
    Registered Member chevynut's Avatar
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    Quote Originally Posted by 55 Tony View Post
    That is not correct. Also I was way off with my 10:1 to 11:1. Looks more like 12.8:1 for max power.
    What's not correct? Adding fuel when there's no oxygen for it to combine to creates zero additional heat energy. Believe what you want. Seems like you start these threads so you can argue with people who reply and try to help you. It might help if you learn something about physics and thermodynamics.

    When you prove you have a problem and give us more data, maybe we can help you. This is sounding just like the "boiling gas" thread.
    56 Nomad, Ramjet 502, Viper 6-speed T56, C4 Corvette front and rear suspension


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  9. #39
    Registered Member chevynut's Avatar
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    Quote Originally Posted by chasracer View Post
    Wow- Anytime you heat up the surrounding air around an engine, it is going to have some effect on the performance of that engine. The engine's ability to shed temperature is not strictly related to coolant temperature as you appear to believe. Oil temperatures, exhaust heat and coatings, air flow around the engine all contribute to the engine's ability to shed heat.
    Sure, everything "contributes" but most of the heat of combustion exits the engine through the exhaust and the coolant. If the engine can't reject enough heat through the cooling system the coolant temperature rises. If you turn off the water pump the temperature immediately soars. This proves that minimal heat loss occurs from the engine surfaces. Any other heat loss is minimal but it helps the engine reject heat though it's not necessary with an adequate cooling system. You could insulate the engine and oilpan and if the cooling system had the capacity to control temperature nothing would change.

    Underhood temperatures have very little or no effect on combustion chamber temperatures. If you have a marginal cooling system, every little bit of heat rejection helps. A theoretical adiabatic engine would be 100% efficient as all the heat would be converted to mechanical energy and not wasted out the exhaust. Besides, the argument is moot because Tony isn't not having a coolant temperature issue. That was my point in the first place.

    As to the alcohol comment, I have to hand it to you - I busted out laughing at your remark. Methanol fuel has an extreme affect on the temperature and performance of our engines. On racing fuel with adequate octane to support our compression ratios, we would have the same cooling issues to deal with that Tony is talking about but running Methanol, I can hot lap any of our cars 7,8,10 shots, doesn't matter, by the time we complete the run and get back to the lanes, our engine temperatures have dropped to 155 or so just due to the fuel.
    Laugh all you want because you clearly don't understand what's going on. Here's what I said..... "The engine is creating just as much heat with alcohol as it did with gasoline." Are you disputing that? To create X horsepower you have to burn Y BTUs/hr of fuel. It doesn't matter what the fuel is.

    As to what happens on the return to the pits, that's a different discussion altogether.

    And again if you really raced you would understand why Pro Stocks, Comp. Eliminator cars and others go through the process of chilling their engines. A cooler engine at the starting line is going to net you a better ET and MPH - each and every time.
    The colder the coolant is, the more heat is lost to the coolant and the less heat is used to push the piston down. You need to cool the engine at the beginning of a run so it doesn't overheat and/or detonate at the end of the run. If a cooler engine develops more power then why don't they run refrigerated water in them in the pits and put 32F water in them before the starting line?
    Last edited by chevynut; 06-14-2018 at 02:44 PM.
    56 Nomad, Ramjet 502, Viper 6-speed T56, C4 Corvette front and rear suspension


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  10. #40
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    If a cooler engine develops more power then why don't they run refrigerated water in them in the pits and put 32F water in them before the starting line?

    They (the Pro Stock guys) do, I already posted that in this thread. Well, maybe only 40°F. Others who don't do it either don't have the resources or they are just going for consistency not max power. It's a matter of money and effort.

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