4efte maximum boost level with a ct9

Discussion in 'The Welcome Section' started by Charith, Mar 9, 2019.

  1. Charith

    Charith Fresh Recruit

    Hey guys i drive a standard automatic 4efete with standard ct9 turbo, rx7 top mount and a adjustable waste gate (Starlet Gt 1993)
    Can i gain 1 bar boost with this set up if so what do i need to do
    Is it ok to run 1.2 bar boost with this set up ?
    Thanks in advance
  2. SKINY

    SKINY Registered User +

    You will need a boost controller, fuel cut defender and a fuel pressure regulator at least. A wideband guage will be handy too, then you just need someone to set it up :)
    Fizturbo likes this.
  3. Charith

    Charith Fresh Recruit

    Thanks for the info
    Do you think getting a ecu for this setup is better or just a fcd, fpr and a electronic boost controller will just do the job fine
  4. SKINY

    SKINY Registered User +

    Cheapest option there is to get a plug n play ECU, theres a few about, Jam, Blitz, Sard etc. They lift fuel cut, speed limiter, more fuel too plus few other features. Likes off a link or e-manage exudes is going to set you back best part of a grand fitted and setup, the pnp ECU,s can be got from 3/400£ :)
    Charith likes this.
  5. Calum122

    Calum122 Registered User +

    Pretty sure the CT9 is way out of its efficiency range by that point.

    When you compress air, you cause it to heat up. A turbo is designed to compress air to a certain pressure. Pressure is directly proportional to heat pV=nRT (Ideal gas law).

    Therefore, just because the pressure goes up, doesn't mean you actually have more oxygen to combust. The turbo must operate at that sweet spot, cranking the boost up past its efficiency range will result in a drop of power.

    The stock CT9 is good for around 0.8 bar, before you just start adding heat, and not oxygen.
    SKINY and Fizturbo like this.
  6. Fizturbo

    Fizturbo Paid Member

    Welcome Aboard.

    As above standard ct9 will puff out unless go ct9 hybrid,cheapest option is fcd unless upgrade to aftermarket ecu,won't need fpr aroun 1bar but be good upgrade along with walbro fuel pump, the rx7 top mount will do the job.

    Last edited: Mar 9, 2019
    SKINY likes this.
  7. Charith

    Charith Fresh Recruit

    But dose those jam ecus supports an automatic engine i have seen them a lot in manual transmission cars. Have you guys heard of a ecu called aem ?.. is this a ecu or a piggy back ?
  8. Charith

    Charith Fresh Recruit

    So a a standard ct 9 with a fcd and boost controller will not get upto 1 bar..?
  9. Charith

    Charith Fresh Recruit

    Looks like i won’t be able to get 1 bar out of a standard ct 9
  10. SKINY

    SKINY Registered User +

    I believe they do buddy, Think Jay is/was running one in his autobox.
    You can run 1 bar on a ct9 but they run outa puff around 6000 rpm, mine was running just before fuel cut at .85 and its pretty sharp, when I fit the fmic the power powerband in the midrange increased and it pulls a tad longer into 62/6300 rpm now.
    Greddy Profec A spec I use
  11. Calum122

    Calum122 Registered User +

    You could ask the turbo to produce whatever boost pressure you like, but as I say, eventually you will just be adding so much hot air into the mix, that the amount of oxygen molecules that will actually be available will be less than if you ran it within its efficiency range.

    I would baseline the turbo at 0.8 bar, then up the boost by other means, I.E. Front mount intercooler, bigger downpipe, hybridised turbo etc.


    It's your basic gas fluid dynamics in action.

    The faster the molecules move around the closed system, the greater the pressure.

    Kinetic energy of molecules in a closed system can be "felt" as temperature. The greater the kinetic energy, the greater the temperature.

    Since temperature at a molecular level is discrete, we can only "feel" the average temperature, which is probably where a lot of misconceptions are misinterpreted.

    This is why bigger turbos are better at producing more boost, since they are not adding as much heat into the compressed air, therefore results in greater number of combustible molecules.

    The easiest way to picture it is, how much better does your car operate on a cold winters evening, compared to the middle of a heat wave in the summer. The colder, denser, air, provides more combustible molecules when compressed to 0.8 bar of boost, than what you get on the summers day. Due to the Idea Gas Law.
    Fez and SKINY like this.
  12. Fizturbo

    Fizturbo Paid Member

    Get up to 1 bar be pushing its limit turbo won't last long depending on its condition , most common problem housing crack & oil seals tend to let go...

    SKINY likes this.
  13. Charith

    Charith Fresh Recruit

  14. Charith

    Charith Fresh Recruit

    How can i get in touch with jay ?
    SKINY likes this.
  15. SKINY

    SKINY Registered User +

    He will be along soon, probably arse up in a gt now lol
  16. Jay

    Jay Admin

    A bar of boost on a CT9 is fairly on the money in terms of peak efficiency, any higher the unit will get outside it's comfort zone but I've seen them run.

    There's a few things you need to upgrade to maintain it's lifespan and reduce the chances of engine failure.

    Think of the engine as a big air pump that mixes fuel into the air then ignites it at the right time to make power.

    First and foremost you need to understand that adding more air to the mixture requires you to add more fuel. If you add too much air without the required amount of fuel you will create a lean mixture. This is very bad for the engine as a lean mixture creates a fast, unpredictable explosion which can go off too soon and hit the piston on the way up. Think of throwing a cup of fuel onto an open fire - big flash and instant reaction.

    So before we add too much boost you need to have the fuel to support it and maintain a good, safe mixture.

    Worth mentioning at this point that adding too much fuel can offer problems too. Say your mixture is at the opposite end and is too rich. The explosion is now slower and nowhere near as powerful. Think of throwing a full bucket of fuel onto an open fire - it dampens down first then burns once it's settled down with little flash.

    The mixture is key. Too rich and you lose power or experience borewash (you can google that bit). Too lean and you start melting pistons and exploding rings with detonation/knock. So it's important you understand this before taking away the factory safety net of fuel-cut. I've seen a lot of folks fit a FCD, turn up the boost then suffer engine failure without realizing why. Some of them proceed to blow up another one or two engines before catching on.
    Fez and SKINY like this.
  17. gorganl2000

    gorganl2000 Registered User +

    sounds like you have pretty decent advice from the members
    i'd prefer you get a piggyback (EMU or EMB) than a plug and play ecu (blitz, jam, Sard, etc)...the piggyback can be tuned specific to your set up, plus you have an automatic which may be a little more difficult to get an aftermarket plug and play ecu anyways

    you will need the above supporting mods the others have told you about for engine safety----i must say i'd prefer you get a FMIC as well if wanting to run approximately 14 psi as i'm not a fan of tmic (even though you have the rx7 unit).
    given your stock engine, and what you have said, i'd probably run anywhere between 10 psi - 14 psi depending on how the turbo/engine reacts and how tune goes
    whatever you do, do NOT turn up the boost without the supporting mods
    decat?, exhaust system? uprated fuel pump (you don't know the age/health of the existing one)? fmic?, aftermarket exhaust manifold? piggyback/pnp/standalone? etc

    also, how has your transmission been maintained?---oil changes? does it carry a filter and does that need changing?....i'm not sure, but may be Jay and the others can help, will he need to think about a transmission cooler?
  18. Rev

    Rev Registered User +

    Fueling is your friend but as said so are supporting mods.
    After fueling and ecu power -
    Power mods on an auto are larger exhaust and downpipe , manifold or ported manifold,intake air from the front and the best FMIC you can find. Healthy compression will help also where carbon is present carbon clean inside engine will reduce knock , my advice is raise boost after mods and map with all mods in place..

    In addition to the good safety mods posted above it is worth mentioning the fast acting intake temp sensor will pull timing when heat is too much.( also gives responsive torque when cool air is present ) and don't overlook the radiator. There is a transmission radiator that partially covers the A/C radiator which completely covers the engine radiator.
    For real figures the power mods above gave paul's auto when Fueling with FPR at 3.1 bar + FCD set to 7 ( not recommending this fueling method for safety)
    with A/C ct9b turbo gave 176.5HP at 6615rpm .9 bar boost ie 13.14 psi
    Last edited: Mar 12, 2019
    Jay likes this.
  19. Calum122

    Calum122 Registered User +


    This is what I was alluding to earlier.

    Graham Bell's Forced Induction Performance Tuning.

    It's not as simple as turning the boost up for the above reasons that I described, but are reiterated in this book.
    Jay, SKINY and Fez like this.
  20. Rev

    Rev Registered User +

    To answer your question more directly No is the answer as 1.2 is at the compressor not the throttle body. Putting it another way the toyosport site says the ct9 48 compressor allows 2.2 pressure ratio ie 1.2 boost at the compressor. Will be less at the throttle body with say 1psi pressure drop translates to 16.7 psi boost for the ct9 max flow of 275cuft/min ( toyosport says .13kg/s) about 200hp at 20degc. Given the stock map sensor cannot read above about 16.75psi this seems reasonable.

    But the superior and safer way to get max flow from the ct9 is to raise the revs eg. like the jam type ecus do in this case typically the ct9 will hit its 275cuft/min. max flow limit at 7500 rpm and just 14psi.
    Last edited: Mar 14, 2019
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