ECU questions
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Thread: ECU questions

  1. #1
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    ECU questions

    If the mi16 engine is supercharged want it give a hp gain even if the ECU isn`t re-mapped ??

    I mean what i can imagine happens is that the air is more easily sucked in by the engine = better performance and engine should rev faster. ??

    I mean the Injectors are suppose to be capable of flowing enough fuel for 195 hp so that means that the engine can be boosed from 150 to max 195 hp before the ECU needs to be re-mapped and bigger injectors installed or changing the whole ECU

    Nitro, according to the sellers all is needed is the original equipment inorder to deal with the +40 hp gain. for more hp then things have to be changed.

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  2. #2
    Fellow Frogger!
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    Hey PugPower,

    A low boost supercharger application should be OK. Many supercharger kit manufacturers do a low boost (5-6psi) kit whilst retaining the factory ECU, and if there's a fueling issue, many put in a rising rate fuel regulator and/or up the injector size. If this is done well (ie a well-calculated upgrade) no ECU changes will have to be made.

    Sometimes the manufacturers don't bother at all with any ECU/fuel pressure/injector changes as most new cars run quite rich up the top end (as a safety margin for poor quality fuels in country areas) - so if you're running a 98 RON fuel and fairly low pressure, intercooled boost, it shouldn't be a prob.

    I wouldn't go around upgrading your Mi16 with say 10psi of un-intercooled boost. I'd even summise 7-8psi is risky as it's a fairly high compression motor.

    If the Mi16 has a MAP sensor instead of an AFM, you will have to replace it with a MAP sensor that reads above atmospheric pressure (most likely a 2 Bar map sensor).

    What supercharger kit have you seen PugPower?

  3. #3
    Fellow Frogger!
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    Nitrous is a different kettle of fish altogether. It would be relatively safe to go and put on a 40hp kit... as I stated before, the cars run quite rich under wide open throttle and at high revs. The nitrous is usually only activated via a switch when you floor it. Pinging is unlikely to occur with a small amount of nitrous as it enters the combustion chamber super-cooled, when the fuel mixtures are rich from WOT.

  4. #4
    1000+ Posts PeterT's Avatar
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    I think the Mi16 would definitely need a different ECU if supercharged. The 195hp barrier would be easily broken, meaning bigger injectors. Bigger injectors mean less injection time at low revs. Increasing the fuel pressure has minimal effect on flow. The flow rate is determined by the square root of the pressure. ie sq. root of 36 (2.5bar) is 6. Sq. root of 42(3bar) is 6.48. This is only an 8% increase in flow rate. A bit like pulling the choke on (if you are old enough to remember!)

    Haltech ECUs can be fitted with 1,2 or 3 bar map sensors. I imagine others are the same. It then becomes a very easy project to manage.

    '92 205 Mi16
    '90 Mi16x4

  5. #5
    Fellow Frogger!
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    Yeah, I just made played around with the javascript turbo calculator @ <a href="http://www.turbofast.com.au/tfcalc.html" target="_blank">http://www.turbofast.com.au/tfcalc.html</a>

    It looks like 6psi is going to be around 220 hp at least.

    PeterT - do you think that with a well calculated upgrade to larger fuel injectors would work at all using the original ECU (in the scenario where the boost is intercooled enough so as to not require ignition retard to stop pinging)?

    cheers
    Adrian

  6. #6
    1000+ Posts PeterT's Avatar
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    Given that a supercharger has boost linear to engine revs, it might just work. The problem would be a rich idle mixture, when there is little or no boost.

    '92 205 Mi16
    '90 Mi16x4

  7. #7
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    hi,

    Well the one i have seen is called Autorotor 3150 the rectangular one.

    <a href="http://www.enem.se/katalog/kompressor/index.asp" target="_blank">http://www.enem.se/katalog/kompressor/index.asp</a>

    The advantage with a supercharger is that it can be re-installed on the next car...

    It sure would be nice to double the power but then i would need to have half the engine changed with new race parts .... and that doesnt come cheap.

    I`ll let you know how things go..

  8. #8
    Fellow Frogger!
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    Sounds interesting PugPower, I'll have a look. Autorotor make some great superchargers, looked into them ages ago for my last car.

    PeterT - wouldn't the ECU's closed loop mode theoretically get rid of this problem?

    As far as I know, closed loop is normally upto 3500-4000rpm (and lower loads) and I thought if it was running rich, the ECU would see that and alter the fueling accordingly... I guess it would depend on the car?

  9. #9
    1000+ Posts PeterT's Avatar
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    Closed loop only works within a range eg 14.7:1 +/- 15%. If the mixture is outside of that range, the ecu won't lock on. But that type of mixture doesn't make horsepower either. 14.7 can only be tolerated under light to medium loads. You need around 13:1 to make good hp on a naturally aspitared injected engine, and far less with forced induction. Most modern cars would never see below 13:1. To give you an idea, the std. Turbo 3L Nissan motor ran about 11:1 on full boost.

    '92 205 Mi16
    '90 Mi16x4

  10. #10
    Fellow Frogger!
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    PeterT

    U can't use that particular engine as an example of a turbocharged cars a/f ratio.
    The nissan RB30 Turbo was designed to run rich
    Because the car was not designed with a intercooler.
    More to the norm is around a/f 12.5.1 of an intercooled turbo factory car.
    Also someone asked regarding bigger injectors & closed loop (The fuel management system will not cope with large injectors)
    U will completely screwup up your driveability & emmitions.


    Murat

  11. #11
    Tadpole
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    I suggest you fit a fuel enrichment system like the MF2 or the Pic5. I did this on my turboconversion and a friend of mine on his supercharger conversion. Keep track of the mixture with a A/F meter. Easy to to use and does the job.
    Compressed air...Yes!

  12. #12
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    thanxs

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