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Thread: EOIT on a TSP 228R. Is my thinking right??

  1. #1
    Tuner in Training FC3S Murray's Avatar
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    EOIT on a TSP 228R. Is my thinking right??

    I need a little clarification:

    I know you all recommend that a camshaft that has 0 degrees of overlap doesn't need EOIT adjusted but the 228R is a pretty aggressive cam with zero overlap. Both EVC and IVO happen at the exact same time...so theoretically there isn't any overlap but not a whole lot of time to spray fuel on the backside of that intake valve.

    The attached EOIT calculator says I need to make my new TRUE settings 6.17

    I read that you want to start spraying about 10 degrees before the IVO event? So somewhere around 6.07 EOIT.

    I have ran an EOIT of 5.29 the last year and noticed a smoother idle and less fuel smell BUT when I re-read these threads for shits and giggles, that just seems contradictive because the exhaust valve would still be open for about 34.5 cranskshaft degrees when the injector starts spraying. Right?? Car runs fine but I sometimes wonder if it is wrong but the error is so minuscule that it really isn?t even noticeable

    I just was curious of anyone's thoughts on this aggressive "zero" overlap cam and what EOIT would benefit it most.
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    Last edited by FC3S Murray; 04-24-2021 at 03:45 PM.

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    Senior Tuner kingtal0n's Avatar
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    I can't follow which tables you are adjusting. The stock setting is 5.55 so I am not sure how you get 5.29 and claim it "better" - better than what? Its even earlier than stock

    Need more info to know what you've adjusted

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    That cam has 49 degrees of overlap at .006 lift.

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    Tuner in Training FC3S Murray's Avatar
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    Quote Originally Posted by kingtal0n View Post
    I can't follow which tables you are adjusting. The stock setting is 5.55 so I am not sure how you get 5.29 and claim it "better" - better than what? Its even earlier than stock

    Need more info to know what you've adjusted
    If you look at my attached EOIT excel spreadsheet you will see that I chose to run a setting of 5.29 over the oem setting of 5.55 due to the fact that my cam starts its Intake Valve Open at 277 degrees. The EOIT calculator says the new normal should be 5.29

    It has worked well so far but like I stated in my original post it doesn?t make sense.

    That cam has 49 degrees of overlap at .006 lift.
    When I run the numbers using 0.050 it says it has 0 overlap.

    Which is it?

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    bit of a read on the understanding of the gen3 eoit

    https://forum.hptuners.com/showthrea...8aAjxIEALw_wcB

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    Tuner in Training FC3S Murray's Avatar
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    So after looking at some more cam event calculators with my specific camshaft specs I am going to try an EOIT of 5.89 and 6.0

    That ends fuel spray at 331.5 & 340 degrees of crankshaft revolution.

    I think 6.17 is going to be too aggressive based off of the EOIT calculator.

    I will datalog some results once the weather straightens out again to see which one is best. I will post it here.
    Last edited by FC3S Murray; 04-12-2021 at 09:02 AM.

  7. #7
    Senior Tuner kingtal0n's Avatar
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    I think you are using 0.050" of lift calculations from your car instead of .006" lift seat to seat.

    All cams have some overlap even OEM camshafts, from 0.006" seat to seat.

    so this was a red flag in your details to me.


    About the end of injection spray, the ideal method is during idle you spray to the back of the intake valve before it can open, this will allow it time to heat and boil from the valve just as the valve is opening. 5.8 to 6.0 is typical values I suppose to achieve this near idle and cruise.

    You do NOT want to spray into an open intake valve around idle and cruise, because liquid fuel may wash down the cylinder walls, causing lost compression and ring/cylinder wear at an accelerated rate.

    What the factory did for GEN4+ and all stand-alone computer modern design will do, is allow different end of injection timing for idle/cruise VS wide open throttle.

    Only Gen3 does not allow this. So there is no way to get ideal end of injection for idle/cruise while also having it spray after the overlap period at wide open throttle for fuel savings in a Gen3 setting. I would err on the side of caution using numerically lower numbers that keep the spray away from open intake event for the safety and longevity of the engine. Until you get a Gen4 or stand-alone application of course.

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    When you have a cam with lots of overlap it best to spray after the exhaust is shut. It sucks not being able to take advantage of the evaporative qualities of the fuel hitting the back of the valve, but unburned fuel out the exhaust pipe sucks even more. Higher exhaust heat, less trapped fuel/air charge in the cylinder, i could go on. you ill need to retune your transient fuel. But there is no reason to leave it the way the factory does it because now we have different operational parameters. You changed the cam and threw the original operational theory of the engine out the window. You will loose some VE down low. i usually set it to 6.1. I try to target the crank angle that is creating the most velocity in the port to get the mix as mixed as it can be. With the 6.1 setting I can get rid of most of the unburned fuel smell even on cars that no longer operate on a public highway (hint hint). There is some torque loss that it think is felt from the less efficient vaporous, cloud vs the larger droplets from the later injection time without the evaporated fuel. My next step for that would be better to use an injector that mists when it injects as opposed to spray like the gen 3 and gen 4 injectors do. (think spray bottle settings) That would be more beneficial. Ive though about having injectors flowed at 80-100 psi to see if the spray pattern improves or gets worse. Id love there to be a patch to change the EOIT to rpm based like in the gen 4's for the gen 3, but thats wishful thinking.

    Chris
    Last edited by Rocko350; 04-18-2021 at 03:56 AM.

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    Senior Tuner kingtal0n's Avatar
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    Quote Originally Posted by Rocko350 View Post
    When you have a cam with lots of overlap it best to spray after the exhaust is shut. It sucks not being able to take advantage of the evaporative qualities of the fuel hitting the back of the valve, but unburned fuel out the exhaust pipe sucks even more.
    This is only true if the fuel can evaporate before it hits the back of the cylinder and runs down the cylinder wall, cleaning all the oil off and increasing the wear and tear of piston ring, causing lost compression over time. I've seen this condition in older engines that are run in this condition for many years. It doesn't happen immediately.


    Higher exhaust heat, less trapped fuel/air charge in the cylinder, i could go on. you ill need to retune your transient fuel. But there is no reason to leave it the way the factory does it because now we have different operational parameters.
    The factory set the injection for a time-delay based on what their models shows that it takes fuel to evaporate from the intake valve fully at specific intake air and engine coolant temperatures. Their goal is more to ensure smooth engine operation by making sure all of the fuel has vaporized or at least as much as possible before the valve cracks open, dribbling liquid fuel down the side of the cylinder.



    You changed the cam and threw the original operational theory of the engine out the window. You will loose some VE down low. i usually set it to 6.1. I try to target the crank angle that is creating the most velocity in the port to get the mix as mixed as it can be.
    I agree it is Ideal, but only if there is sufficient temperature and velocity to actually get the job done. At idle and when cold this may not be enough for this type of injection strategy. Also very high flow rates at wide open throttle from large injectors using Alcohol can be very potent. The cam reduces the pressure of the intake so it also becomes more difficult to boil off the liquids. Together this can spell eventual doom for the cylinder wall and piston ring seal if enough liquid fuel is washing them down repeatedly for many years using a late injection.



    With the 6.1 setting I can get rid of most of the unburned fuel smell even on cars that no longer operate on a public highway (hint hint). There is some torque loss that it hink is felt fro the less efficient vaporous, clud vs the larger droplets from the later injection time without the evaporated fuel. My next step for that would be better to use an injector that mists when it injects as opposed to spray like the gen 3 and gen 4 injectors do. (think spray bottle settings) That would be beneficial. Ive though about having injectors flowed at 80-100 psi to see if the spray pattern improves or gets worse. Id love there to be a patch to change the EOIT to rpm based like in the gen 4's for the gen 3, but thats wishful thinking.
    Chris
    Its a great place to be for gen4 and any stand-alone because they utilize a map which can retard injector spray for low rpms and advance for low rpm cruise situations where port velocity is higher and temp is higher. Or for large volume injections of alcohol at WOT when you don't care about fuel smell or fuel savings and would rather protect the cylinder wall from washing down with liquid alcohol so you retard the spray back to closed valve. Advancing to try and skip the overlap period is only for short pulses of fuel at moderate-light engine loads where the vehicle is cruising along with low pulse width and desires maximum economy with no risk to the cylinder wall or piston ring.

    But the gen3 cannot do that and so I Cannot recommend such type of settings.
    Last edited by kingtal0n; 04-15-2021 at 07:17 PM.

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    When using this calculator, do you input @0.050" or @0.006" valve event numbers?

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    use .006 events as they affect the overlap, my cam was 5 deg at .050 but 57 at .006 so can be a big difference

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    Quote Originally Posted by 07GTS View Post
    use .006 events as they affect the overlap, my cam was 5 deg at .050 but 57 at .006 so can be a big difference
    Thanks

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    Quote Originally Posted by FC3S Murray View Post
    So after looking at some more cam event calculators with my specific camshaft specs I am going to try an EOIT of 5.89 and 6.0

    That ends fuel spray at 331.5 & 340 degrees of crankshaft revolution.

    I think 6.17 is going to be too aggressive based off of the EOIT calculator.

    I will datalog some results once the weather straightens out again to see which one is best. I will post it here.
    Did you ever get a chance to data log this? I would like to see your tune also.

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    dont focus too much on meeting exact degrees according to your camshaft as there can be some more in it we cant see, on the gen4 eoit the stock settings calculate out the be right for my camshaft delay but yet i had to delay it 35 deg further to get more fuel in the chamber, thats why i just use the wideband/trims as as it will show richer when more fuel is going on or not based on actual events

  15. #15
    Senior Tuner kingtal0n's Avatar
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    That is something I Never did understand when people throwing around EOIT terminology

    For example when they say " I Set my EOIT to just after overlap " To me that means the injector is going to spray right through overlap period.


    In other words, you need enough time AFTER overlap has ended to BEGIN spraying the injector (Start of Injection time) and be able to finish that before the intake valve closes (EOIT) so you need EOIT + Some number of degrees to get the full injection inside the cylinder and it can't be very long or you run right up into overlap again. Depends on the RPM, but pretty much guarantees that with this setting it will spray at WOT through overlap period every single time. Which is why I don't like doing it in gen3 applications.

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    after about 3000rpm overlap shouldnt be an issue as it should be doing its job and getting more air into the chamber not out the exhaust, just get it better for idle then gen3 ur done cant do any more

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    Senior Tuner kingtal0n's Avatar
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    Quote Originally Posted by 07GTS View Post
    after about 3000rpm overlap shouldnt be an issue as it should be doing its job and getting more air into the chamber not out the exhaust, just get it better for idle then gen3 ur done cant do any more
    The problem isn't the fuel washing out the exhaust,


    the problem is the intake valve is open while the injector is open,

    causing a stream of fuel to spray down the back of the cylinder, washing off the oil, increasing wear and tear of the engine

    presumably the reason the factory doesn't do it this way

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    Quote Originally Posted by kingtal0n View Post
    The problem isn't the fuel washing out the exhaust,


    the problem is the intake valve is open while the injector is open,

    causing a stream of fuel to spray down the back of the cylinder, washing off the oil, increasing wear and tear of the engine

    presumably the reason the factory doesn't do it this way
    my understanding is its just for emissions the way factory has it, if it were for cylinder wash then DI and carby engines wouldnt last long, if the fuel dosnt get the cylinder walls im sure the flame front will dissolve up any left over oil anyway

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    Senior Tuner kingtal0n's Avatar
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    Quote Originally Posted by 07GTS View Post
    my understanding is its just for emissions the way factory has it, if it were for cylinder wash then DI and carby engines wouldnt last long, if the fuel dosnt get the cylinder walls im sure the flame front will dissolve up any left over oil anyway
    Carbs don't inject a pointy spray of ethanol directly at the valve. Air flowing into the carb draws fuel in gradually, constantly, it happens non stop so the fuel is spread out over the entire 4-stroke cycle and not injected suddenly within 1ms at the last instant all at once like a fuel injector.

    DI injections operate with something like 2000psi to forcefully atomize the fuel at extremely high pressure, and it is directed away from the cylinder walls and into a small chamber as the piston is approaching TDC.

    Factory injector timing over valve is set to provide vaporization time for the fuel to evaporate from the valve. Fuel is injected as a liquid to the valve and then the engine has some time for the valve to boil off the fuel before the valve opens.

    There is no comparison here. I've seen the results of fuel washing down cylinder walls and although it can take 20k to 40,000 miles to show up it does kill compression and ruin the cylinder walls. Speaking from 20+ years of experience

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    Quote Originally Posted by kingtal0n View Post
    Carbs don't inject a pointy spray of ethanol directly at the valve. Air flowing into the carb draws fuel in gradually, constantly, it happens non stop so the fuel is spread out over the entire 4-stroke cycle and not injected suddenly within 1ms at the last instant all at once like a fuel injector.

    DI injections operate with something like 2000psi to forcefully atomize the fuel at extremely high pressure, and it is directed away from the cylinder walls and into a small chamber as the piston is approaching TDC.

    Factory injector timing over valve is set to provide vaporization time for the fuel to evaporate from the valve. Fuel is injected as a liquid to the valve and then the engine has some time for the valve to boil off the fuel before the valve opens.

    There is no comparison here. I've seen the results of fuel washing down cylinder walls and although it can take 20k to 40,000 miles to show up it does kill compression and ruin the cylinder walls. Speaking from 20+ years of experience
    im not worried about a 1ms PW of mist from an injector 3-4" above the valve in the port at idle causing any issues being delayed a little