Going multi-port

Discussion in 'High Tech for Old Iron' started by uwasbuick, Feb 11, 2012.

  1. uwasbuick

    uwasbuick NO, IT'S NOT A CHEVELLE!

    I have been reading some of the other posts about fuel injection, both multi-port , and TBI. I am intrested in building a multi-port, sequential fuel injection system. I have done some nosing around, and figured it could be done for a "reasonable" price. My question is... What is the formula for figuring out what size injectors to use? I know I'm still in the planning stages, but am really intrested by the challenge of modernizing my old iron! It will be on a 462 ci with either a TA212, or TA413 cam, '71 stage 1 iron heads that have been cut, have the high flow valves, and a mild port matching job, with hopefully the TA SP1 intake. Not sure about the compression ratio, but guessing around 10:1. And yes... A TH200-4r and low 3:08 gear for the milage. Any ideas?

    Thanks, Josh
     
  2. pmuller9

    pmuller9 Well-Known Member

    There are plenty of online calculators.
    The calculations are based on the following.

    The Brake Specific Fuel Consumption (BSFC) is the amount of fuel it takes to make one horsepower per hour.
    For a naturally aspirated engine it is around 0.5 lbs per hour

    So if you figure the engine will produce 450 hp, then the engine will use 450 X 0.5 or 225 lbs of fuel per hour.

    Since there are 8 injectors then each injector will use 225/8 or 28 lbs per hour. (rounded)

    But injectors should only be operated at a max duty cycle of 80% so 28/.8 = 35 lb/hr

    Round up to the nearest avialable size.

    This is based on a fuel pressure of 43.5 psi. You can adjust the fuel flow up by raising the fuel pressure if needed

    There is a big difference between a TA212 and a TA413 cam.

    With 3:08 gearing you will want plenty of low end torque. The low 1st gear in the TH200-4r will help also

    If you are going for gas mileage then you also want to keep the valve overlap at 0 degrees or less.

    The TA212 would be a good choice.

    Because of the relatively short advertised intake duration of the TA212 cam, the compression ratio needs to be 9.5:1 or lower

    Paul
     
    Last edited: Feb 12, 2012
  3. TheSilverBuick

    TheSilverBuick In the Middle of No Where

    I ran the TA-212 cam for around 10,000 miles with iron '70 heads opened up with larger valves and 10:1 cast pistons with shorty headers and the SPX intake. I ran a set of 3.08 gears out back with a 26" tall tire and a 5-spd manual with .64 overdrive. I ran into pinging problems at lower rpm at low elevation, and eventually broke some ringlands pulling hills outside of Vegas on hot days in overdrive. Over all I was happy with the combination, but probably could of used either shorter gears or better head/piston combination to stave off detonation. Or my tune may of simply been too lean and lead to too much detonation. I calculated my compression at 9.6:1 with the pistons .030" in the hole and standard Felpro head gaskets. I was averaging 19.5mpg on the highway, repeatably. Oh yeah, the car is 3,800lbs.
     
  4. uwasbuick

    uwasbuick NO, IT'S NOT A CHEVELLE!

    So do you guys think the TA413 is going to be too big for the rest of the combination? Silverbuick, you actually poped some of the ring lands on your cast sluggs? That makes me a little weary now, I was going to run some .030 over hypereutectic pistons I bought years ago. with clearences tighter for those, detonation is a REAL concern! Do you guys have anything to moniter your exhaust gas to prevent leaning, or detonation? Thanks, Josh
     
  5. Nothingface5384

    Nothingface5384 Detail To Oil - Car Care

    42lb injectors would do ya ok with power and duty cylce to spare down the load if combo gets more wild



    if you need a fuel pump and regulator i have a 1300hp fuelab and matching regulator for sale if interested
     
  6. DaWildcat

    DaWildcat Platinum Level Contributor

    Quick question...shouldn't any detonation be considered "too much"?

    Devon
     
  7. Tyler Northcutt

    Tyler Northcutt Just an old pile of parts

    Yes, and all to often by the time you hear it the damage has already been done.
     
  8. pmuller9

    pmuller9 Well-Known Member

    Josh

    The 413 cam in meant to make power more towards the 5500+ rpm range.
    Unless the intake and exhaust ports (bowl and runner areas) have been worked to increase airflow
    the heads will choke off the power the 413 cam is trying to make at the upper rpm range.
    Then with the loss of low end torque because of the larger duration, the power band becomes very narrow.
    Here is the comparison between the TA212 and the TA413.
    Look at the resulting power chart at the end of the article.

    http://www.carcraft.com/techarticles/ccrp_0906_buick_455_engine_bolt_ons/viewall.html

    The second thing to consider is the 413 has 13 degrees of overlap which is not good for gas mileage
    or manifold vacuum for power brakes.

    The hypereutectic pistons will not give you the room to experiment with timing or A/F ratios without the fear of
    damage due to detonation.

    If you plan on using the TA212 cam you can minimize the chance of detonation by doing the following:

    Actual compression ratio not over 9:1
    Polish the combustion chamber so it is smooth with no edges or casting lumps that can become hot spots and cause pre-ignition.
    Use the TA high performance water pump with a good radiator and a 160 degree thermostat.
    Do not allow the engine to take in the hot air from the engine compartment.
    Either grab cold air from a sealed hood scoop or snorkel it in from in front of the radiator, behind the grill.

    If a larger cam is used then the compression ratio can be higher but the rest is still a good idea.
    It is easier to get 9:1 compression if the piston has at least a 30cc dish.

    Will you be using the stock exhaust manifolds or headers?

    Paul
     
    Last edited: Feb 13, 2012
  9. TheSilverBuick

    TheSilverBuick In the Middle of No Where

    Yeah, the pistons had about 35,000 miles on them though. Most that time with the TA 118 cam and 3.70 gears. So I kinda think it was the 3.08's that took away my ley-way with the AFR's being a bit lean while loaded up. My set up was set lean by me for attempting to get better fuel mileage, it just wasn't ready for pulling a 5%-6% grade for several miles in 100+*F temps. The overlap might not be good for mpg's but it might help on the sensitivity to pinging.

    On the fuel side. I ran a junkyard sourced Ford fuel pump from a late 80's truck for a couple of years before replacing it with the same pump sourced from NAPA just because I was going to run Drag Week and wanted a new pump. The junkyard one remains my backup spare. It's only a 5/16th diameter, but supposedly rated at 90psi, so turned down to 43psi it does okay so far. With a standard Aeromotive fuel pressure regulator the fuel system does good. I ran 32lb/hr injectors from late 2009 to last September. I upgraded to 45lb/hr ones after going to aluminum heads, more compression and a larger cam (roller) for piece of mind. I ran a couple soft passes down the track with the 32lb/hr ones and wasn't sure if when I really was hard on it if there would be enough capacity. I contemplated turning up the psi on the regulator first, but opted to simply swap injectors and now I'll use the 32lb/hr ones in my OHC L6.

    [​IMG]
     
  10. supremeefi

    supremeefi supremeefi

    Always use the smallest injector possible, and turn up the pressure.
    42's are good for 600+hp with no power adders. I made 621 witrh 42's no problems. If you're estimated power is going to be 500 or below I'd use 30-32's with 50-55psi of pressure.

    Any piston will go south once it expierences detonation, hyper pistons don't like rpms (6000+) but are good in moderate hp'd applications.
    But a good efi system will allow you to tune the spark curve for maximum hp/tq while being able to remove timing as the motor gets hotter.
     
  11. TheSilverBuick

    TheSilverBuick In the Middle of No Where

    I'll find out how much HP I'm making at some point this year when I go to a chassis dyno. Plus I leave room to upgrade the cam and start kicking out real horsepower. BUT I do expect to run out of fuel pump capacity at some point, but for now it seems good supplying fuel to the engine at WOT and 6,000 rpm.

    I had the intake air temperature sensor pulling timing, but it was not enough to offset the 4,000 feet drop in elevation. New code for MegaSquirt is being written to let the timing be adjusted in real time by the barometer readings like the fuel is. Not to many people run into this issue, primarily those that live at high elevation. Basically it's set up at normal intake temperatures, at home at 6500ft, WOT max timing is set for 33* (which pulls down to 28* when the intake temps get over 180*F, likewise for coolant but at a higher temp) but at WOT at <2000ft elevation it'd ping, but if the timing calculations could take into account denser air from the barometer then it could pull timing to ~30* or something. Similarly for cruising. If I cruise at 44* timing (@2200rpm) at high elevation, when I get to denser air it might only want 40* timing. Less air and less air pressure supports more timing advance because the flame front travels slower. As far as I know none of the systems modify timing based on elevation, but most due on temperature, intake and coolant.

    I 100% agree! Promotes better atomization. Standard fluid dynamics or something. For better atomization go for a larger pressure differential and more orifice/nozzle passages.
     
  12. BRUCE ROE

    BRUCE ROE Well-Known Member

    Sequential injection will require cam sync and an ECU with 8 injector drivers. A special distributor
    can provide cam sync. What parts are you thinking of using? Bruce Roe
     
  13. S2X01

    S2X01 Well-Known Member

    All of this makes me happy.....good stuff to know!!
     
  14. uwasbuick

    uwasbuick NO, IT'S NOT A CHEVELLE!

    I was planning on using the mega squirt 3 With eight channels because my idea was to go distributerless also when I went to the sequential fuel injection. So, is there no provision for a MAP sensor with the mega squirt then? I thought it was the duties of the MAP sensor was to moniter Manifold Absolute Pressure and that tells the ecu to adjust timing curve? Also for more fuel atomazation, I was thinking about installing the fuel injectors with a slight upstream pitch, but wondering if this would create a flow issue for the air flow to the cylinder. I really can't see the combination i was going to use being more than 500 hp. , so I was thinking 32-36 lb injectors. And I wasn't really sure what to do about the fuel system yet(I hadn't made it that far). Will I be able to use my stock gas tank? I've seen fuel injected specific fuel tanks, but didn't know if it was required? Thanks for the offer Mike on the fuel pump set-up, but I'm nowhere near ready for that. Thanks alot for the input guys!! Josh
     
  15. TheSilverBuick

    TheSilverBuick In the Middle of No Where

    ALL MegaSquirts come with a built in MAP sensor. Then if you want to install either the MAPDaddy upgrade or simply run a second MAP sensor for barometric corrections then there is an input on the board for it the second sensor. The MAP VE tables have the x-axis as RPM and the Y-axis as Manifold Vacuum divided by Atmospheric Pressure (MAP/Baro). The fuel and ignition are mapped this way. With no second map sensor it gets an initial reading when the vehicle is started as the Baro reading, otherwise it gets a real time number. Because guys like me can drive from high up on the mountain to low down by sea level without shutting the car off a real time number is preferable, but a closed loop O2 sensor feedback can work too.

    The curve I mentioned earlier about timing is more complex. Because air doesn't just change pressure, it changes density too with elevation a few adjustments to the fuel table have to be made besides simple more air pressure means more fuel is needed, because the air density is more. Anyways MegaSquirt has a baro table that lets the fuel trim be tweaked non-linearly based on the Baro reading. Each vehicle's curve can be slightly different due to cam, intake and exhaust designs.

    Example being. Here in Ely the atmospheric pressure averages around 85kPa. So WOT puts the fueling at the top of the table, 100% (85kPa/85kPa) which requires a different amount of fuel than driving at sea level at 101kPa, because 100% is 101kPa/101kPa not the same as 85kPa/101kPa. This is simple barometric correction for fuel. It's pretty flexible and works well. For spark though there is a problem with not having a non-linear or even linear scaling by Baro. Because at 85kPa and WOT, 100%, the engine may tolerate 35* of advance because the less dense air makes less cylinder pressure and has a slower flame travel speed, so when corrected to sea level and go WOT it's now at 101kPa, more dense air, more cylinder pressure and suddenly 35* at 101kPa/101kPa (100%), makes the engine ping. No good. Same goes for cruising timing. At 85kPa baro the air is less dense the engine can tolerate 45* of timing because the lower cylinder pressures, where as 101kPa the air is denser and the engine may only tolerate 42* of advance for the faster flame front travel and any higher will mis-fire. Basically cruising at a 30% manifold/atmospheric differential at high elevation is different than cruising at a 30% manifold/atmospheric differential at low elevation because of air density. The pressure is being accounted for, and for fueling the density is accounted for on pretty much all EFI systems, just some are real time and others off an initial reading.


    On the fuel system. I'm using a ~$100-$120 Ford fuel pump stocked on the shelves at NAPA with an Aeromotive fuel pressure regulator. I'm using my stock gas tank with a priming pump (stock 455 mechanical pump) and a surge tank. The system has been bullet proof for ~35,000+ miles since 2009. If you are going to be spraying fuel against the air flow it will definitely have a negative effect on airflow. Roughly 14psi of air pressure pushing it's way down the intake and then having roughly 43psi of fuel spray pushing it back up the intake. The engine will certainly run, and probably pretty decently, but there will be a lot of power left on the table in terms of air flow. At least I'd think so.
     
  16. BRUCE ROE

    BRUCE ROE Well-Known Member

    Distributerless is cool. Mine runs a crank trigger and waste fire, which means every plug
    fires every crank revolution. But you still need a cam position sensor to run sequential
    injection; if not in the distributer, then where? Bruce Roe
     
  17. TheSilverBuick

    TheSilverBuick In the Middle of No Where

    I run a crank trigger too with thoughts of going distributorless. As far as I know the only way to go sequential requires a sensor off the cam to locate cylinder #1. This can be done a couple of ways, but all involve the distributor. One is using a Grand National cam sensor, it'll drop right into the 455's distributor hole in the timing cover, just the distributor gear needs to be swapped out for a 455 one. Another method is to use an electronic distributor with all but one of the reluctor and pickup teeth ground off. And a method I'm contemplating using on my OHC six is to use a points distributor and grind smooth all the point lobes except one and use a set of point contacts to trigger when #1 comes around. It's worth mentioning though, going to a distributorless or wasted spark ignition system does not require the system to be sequential. If I do go distributorless I won't be going sequential and the distributor or cam sensor will be in my engine just to turn the oil pump.
     
  18. pmuller9

    pmuller9 Well-Known Member

    You may have mentioned this before and I missed it but why not go sequential on the fuel?

    Paul
     
  19. TheSilverBuick

    TheSilverBuick In the Middle of No Where

    Pretty much requires an upgrade to MS3. I know there are ways to do sequential with the MS2 I'm running but I'm not sure if it'll do sequential on a V8, or even if it does it would likely cannibalize my IAC valve outputs to pull it off. Upgrading the MS2 to an MS3 isn't that difficult or too expensive, but value of HP versus cost and R&R'ing my wiring harness isn't worth it to me. Personally, I would only do sequential IF I ran either a wide band O2 or EGT sensors on every port for the tuning and use the sequential for balancing AFR's. I plan on doing this with the OHC six because the funky shape of some of the ports and because the possible intake designs and very uneven runner lengths. The phasing with the closing of the intake valve is cool, but at my HP levels I really don't expect a ton of HP gains to be made. Plus that work is best determined with a dyno, which to date I've yet to go to. One guy I know made a shade over 1,000HP N/A with a BBFord and batch firing (EMSPro/MegaSquirt 1), and with sequential (MS3) picked up around 30HP iirc. My gains I'd expect to be less.
     
  20. pmuller9

    pmuller9 Well-Known Member

    I was thinking more along the lines of fuel phasing at low rpm for the sake of gas mileage.
    It works out better if the fuel is injected just before and during the begining of the intake stroke and not during the end of the intake stroke when reversion can occur past the intake valve and back up the runner.

    Paul
     

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