warming car up

Discussion in 'InsideTopAlcohol.com Tech Questions' started by dragster156, Nov 3, 2019.

  1. dragster156

    dragster156 Member

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    Since the cars use so much fuel today and even at idle they really hammer the new oil with alky and start contaminating it. Even though it can go a race how many people (roots application if that matters) if the car would call for a 70 main in the BV on the run start and warm it up with something much leaner to keep things less contaminated (ie 85-90 main)

    There is no reving the engine. It's simply a start up and run through gears to get things up to temp. Max rpm might be 2300 or so, but as said most of the time just 16-1700 idle.
     
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  2. Mike Canter

    Mike Canter Top Dragster
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    Just to let you know that your main jet size doesn’t come to play when at idle and oil contamination is caused by rich barrel valve adjustment. The barrel valve uses the slot in the spool with the excess fuel going back through the idle return check valve. If you are contaminating oil with alcohol then you need to change your barrel valve leak down percent by a couple smaller. You can keep leaning it out as long as you don’t get a hesitation if you quickly rev the motor off of idle. If it blubbers off of idle it is too rich, if it hesitates it is too lean. It should be nice and crisp and aggressive sounding
     
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  3. dragster156

    dragster156 Member

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    Now that you mention it I remember being told that last year. Just slipped my mind.
    I will make the adjustment and see how it goes.

    Appreciate the heads up.
     
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  4. aj481x

    aj481x Member

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    A way to get a faster, cleaner warmup. Start motor, then have driver squeeze fuel shutoff until engine comes up to around 2500 rpm. If you are going to do any rpm tests put it back on full fuel.
     
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  5. Mike Canter

    Mike Canter Top Dragster
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    I agree in what you are saying about using the fuel shutoff but it is obvious his BV is out of adjustment so I would adjust it correctly first then use the fuel shutoff trick
     
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  6. dragster156

    dragster156 Member

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    I agree and have done the fuel shut off thing. Just wondering if there was a diff method.
     
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  7. lucky devil

    lucky devil Member

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    Have an oil heater in the tank or in the pan , ensure that the oil is up to 100f first , I would agree with squeezing the fuel shut off too.
     
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  8. GregM784

    GregM784 Member

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    When i start mine, the pump immediately comes back about 1/2 way. It'll idle @ 1900-2000, i trim it until it's about 2300-2400 and let it build heat. While it's trimmed, it's also in high gear to warm up rear end/trans.

    Make sure it's full on when you do any transbrake/RPM testing.
     
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  9. dragster156

    dragster156 Member

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    I only heat the oil in the early spring months and later fall months. In the 90-100 summer heat I do not bother. Should I still??

    Yes I will just do the fuel trimming with shut off. Keep it simple
     
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  10. GregM784

    GregM784 Member

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    I don't. the oil builds heat pretty quick. I can watch the oil pressure gauge for it to drop to it's normal hot range and my crew chief watches oil temp. Just make sure the oil is to temp before you rack it. :)
     
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  11. Will Hanna

    Will Hanna We put the 'inside' in Top Alcohol
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    In my tuning experience, the barrel valve adjustment should be to hit a target cylinder head temp at staging (and part throttle stage flow if you have clutch car or part throttle converter leave). The trend over the years is to have a cool head at stage, so the idle flow is going to be on the rich side if you are doing that.

    As mentioned, I have trimmed the fuel shutoff during the warm up to accomplish this. Usually trim it just enough to bring it off idle.

    Every roots car I have tuned, I've been able to get a clean idle that doesn't get the heads too hot, so I rarely have to trim the fuel shutoff to warm it up.

    I run a pretty rich idle mixture with a screw car, so almost all of them I've had to trim back. The thing you want to be careful with a screw is to not trim it too far. If you get it too lean at idle, you will heat the blower up and potentially cause damage. I always reach under the back of the blower and feel the case where the rear plate bolts to the case to see if there are any signs of heat. There should be none. If so, give it some more fuel at idle until it quits feeling warm. If you have a dash and flow meter, you can trim it to a target gpm.

    During normal temps, I idle for 90 seconds with the fuel shutoff trimmed. Cooler temps will take 120 seconds. I make sure that I can feel heat in the oil line going to the filter before I turn the fuel back full open.

    I never touch the throttle with the fuel trimmed. When it's back open, with a clutch car, that's when we bring it to stage rpm.

    I usually bring the motor up myself as well and do a good throttle gap. Why? Because it sounds cool. That said, I'm not a fan of gapping the throttle off idle.
     
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  12. lucky devil

    lucky devil Member

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    I ALWAYS warm the oil regardless of ambient Temp , it is the life blood of the motor and something I have always done , it helps get rid of Methanol in the oil too
     
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