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  • Keeping your Boosted Colt alive

    Got my car tuned by Steve Knight Racetech today and he had some words of advice which I think are worthwhile being passed on.
    I'm sure there be some comment from all the 'experts' who apparently know-it-all but I'll stick with a professional (Mitsubishi) tuners advice thanks very much...

    Anyway:
    • Put cable ties around the boost feed hoses into the fuel pressure regulator on both ends. If the boost line blows off the fuel pressure regulator the engine WILL lean out and blow. (Photos below)
    • Got Boost? Increase the viscosity of your oil. With increased boost goes increased load, increased load = thinner oil film on your bearings increasing the liklihood of seizure. With 20psi Steve told me he recommends running 20w-50w or 15w-50w at least to protect the big end. Standard boost = OEM recommended oil viscosity. Also says to run standard Mitsubishi filters.
      NOTE: The recommended oil viscosity mentioned by Steve is applicable to the Australian climate only. Sub zero temps (<-10C etc) over in the EU or Japan would obviously need to be considered when choosing your viscosity. The Ralliart Colt Manual page 12-4 refers to this but again take boost into consideration as well.
    • Leave the standard Mitsubishi rev limiter where it is. It's a small turbo and the engine/turbo combination is not designed for heaps of boost at high revs. The boost tapers for a reason.
    • Keep the fuel up to the Colt when increasing boost. Detonation is the killer of all turbo engines; bigger fuel pump, bigger injectors whatever... Don't let it lean out and watch the injector duty cycle!
    • Running E85 don't use synthetic oil, use a mineral based oil as the E85 isn't compatable with synthetics.

    He seems to think that the stock internals of a colt engine could feasibly handle >25psi if you keep the fuel up to it. He has tuned Evos and Sigmas with standard internals up to 28psi with no failures.
    This advice coming from a guy who worked for Mitsubishi Oz doing engine tuning and development work for over 10 years. Did R&D with Ralliart/Mitsubishi Japan on numerous models and raced Mitsubishis for years.
    SKR is the first tuner I've been to who actually takes the boost feed from the line going to the fuel pressure regulator. Every other tuner I have seen takes a feed from the intake manifold. Makes sense really, if you're not seeing the boost pressure to the fuel pressure regulator the you may be getting an incorrect reading and increasing the danger of a lean-out condition.

    NOTE:
    This is advice only - I'm not going to stump up for your shitty holed engine block if a rod decides to let the daylight in. You're all big boys & girls, work it out.
    Exercise caution with your tuning and be realistic about what you (And your engine) can achieve.

    Side note: On one of the shelves down at SKR was a very pretty piece of forged rod with a forged piston attached that had exited the inside of some poorly tuned Evo. The cause? You guessed it, DETONATION!!!

    Input from some Singapore colters.
    This is advice only from one of the forum members and isn't backed up by any specific tuner as such. It's still valid info I feel as those Sg guys have blown a few colts up yet they also have some of highest output colts on stock internals, 300hp using a hub dyno. Make your own decision but it is essentially backed up by their results.
    So:
    1) Do not exceed the standard Mitsubishi rev limit set by the factory unless you have upgraded the rods and other supporting internals, they are plasticine and will fail.
    2) Do not exceed 400nm (hub dyno) with stock internals, anything above this dramatically increases the likelihood of letting the daylight into your engine.
    I think there's also some of the Sg guys running stock clutches at this power level with no probs - don't quote me though and it probably requires a delicate left foot to keep it alive.

    Some linkys to around 3 pages of Dyno Printouts with corresponding mods listed at the bottom from the Singapore Colters courtesy of Espionage8 - Thx mate!
    http://www.rcolt.com/showthread.php?...ght=espionage8
    If you want to know the wheel hp, divide the HP figure by the TCF factor written on our dyno charts. That's the transmission correction factor. Espionage8's TCF is 1.2 therefore if u divide my hp by 1.2 he has about 245whp. The auto colts in Singapore have a tcf of 1.25 so u gotta divide their figures by that tcf amount to get their whp.


    (Indirect) Input from Martin Donnen of Willall Racing fame
    NOTE: THIS IS GUIDANCE ONLY!!! But it is from a reliable source as per the HPI article.
    http://www.rcolt.com/showthread.php?...hat-does-it-do
    Martin talks about how high boost at low RPM contributes to bending the rods which in turn loads the piston differently to what it was designed. This then causes the piston end bearing (Gudgeon, little end etc) and pin to basically seperate at the weakest point. The bent rod may even cause the piston skirt to hit the crank and contribute to smashing the piston apart; next step is the rod thrashing around and Hello!! daylight.
    Make your own mind up, but I think it's a good description of what's been happening.
    So the solution? Get a bigger turbo!!
    Obviously there is a limit as to how big you can go on stock internals but a stock WRX spec TD04 or a hybrid TF035-15T is about as big as you wanna go. TF035-15T is as yet untested but the Singapore Colters are getting up to 300hp (Hub dyno) on stock internals with the TD04.
    http://www.rcolt.com/showthread.php?...s-in-your-Colt

    AFRs and Duty Cycle

    Showing the difference between AFRs at higher revs. Check the lower graph at the extreme right of the page for the area in question.

    The lower graph in the first image shows how the AFRs are at 11.5 above 6000rpm - with 20psi of boost tapering down to around 15psi @ 6000rpm gives athe standard 275cc injector a duty cycle of 97.7%.
    The lower graph in the second image shows how the AFRs are at 12 above 6000rpm - with 20psi of boost tapering down to around 15psi @ 6000rpm gives athe standard 275cc injector a duty cycle of 80.7%.

    That's a 17% difference with just 0.5 difference in AFRs. Steve advised that anything above an 80% duty cycle he would fit bigger injectors as there's no insurance against lean out condition.
    Dont forget these figures are taken from my car fitted with a Walbro 225 fuel pump at the time of the tune. That means increased pressure and flow over the standard fuel pump. They're cheap and are definitely good insurance so get one sooner rather than later if ur modding ur car. They're basically a bolt-in mod but they do require some trimming of the plastic 'in-tank' pump holder.

    http://i1038.photobucket.com/albums/...AFRabove6k.jpg

    http://i1038.photobucket.com/albums/...AFRabove6k.jpg




    Pictures of cable tied Fuel pressure line:

    http://i1038.photobucket.com/albums/.../Cableties.jpg

    http://i1038.photobucket.com/albums/...m/IMG_1823.jpg
    Last edited by odysseyesm; 31-08-2012, 09:25 AM. Reason: Updates - SG info and dynos

  • #2
    Yeah agreed.

    I think i'm the first to have gone over 25PSI and didn't blow up + 137kW and injectors maxed. Steve put it really really rich to the point I was getting 2-300km per tank though. - but it was my fault that I went to Steve prematurely not knowing what i really want so he just tried to max it out i think. Or maybe he was lazy did't focus on mine with time attack on his mind.

    I've since learnt from him and did most of it myself and turned it down by a lot achieving optimal power and torque.

    Comment


    • #3
      During the initial tuning after fitment of the Forge wastegate it hit just over 25psi @ 3500 revs before he shut it off.
      I got a little excited when I saw that ramping up... Not so much the boost level but the AFR was at 13.5 - plenty of power but not for long!
      Checked the log and no knock recorded for that event.

      Comment


      • #4
        Thanks for the info dude, that's good info from a good source.

        Comment


        • #5
          Something else I just thought of, the last couple of runs we did there was a difference in the injector duty cycle that was very significant. One run got 130 odd Kw with a 97.7% duty cycle and two runs later Steve cleaned it up to a final figure of 135Kw @ 80.7% duty cycle.
          I didn't change over to the bigger WRX injectors, I'm still running the stockies. But what stuck with me was the small variation in AFRs high in the rev range and the impact it had on duty cycle and pulse width.
          I'll track down the two maps for comparison and highlight the area I'm talking about.
          Last edited by Corosith; 27-03-2012, 12:39 AM. Reason: stockies, not stickies!

          Comment


          • #6
            I noticed that too, Steve only had to make subtle changes to the AFR for the injector duty cycle to drop right back to an acceptable range - the wonders of tuning!

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            • #7
              Very nice.

              One thing to mention is that the fuel pressure regulator is pluged into a solenoid for cold starting. It's not connected direct to the intake manifold.

              It amazing how much easer it is to tune with logging boost and afr's.

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              • #8
                Great post man. Sticky for sure

                Sent from my GT-I9100 using Tapatalk

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                • #9
                  great stuff
                  maybe add to the list not to load the engine to much in higher gears+low rpm, most will allready know but not the newbies
                  also, where is the fuel pressure regulator? any pics?

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                  • #10
                    More info added to first post on AFRs and injector duty cycle.

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                    • #11
                      Hey guys, I dont know anything on tuning. What is the most ideal % of the injectors? does the stock ECU run them at say 60% duty?

                      Comment


                      • #12
                        Originally posted by Satio View Post
                        Hey guys, I dont know anything on tuning. What is the most ideal % of the injectors? does the stock ECU run them at say 60% duty?
                        See the bottom of the first post.

                        Comment


                        • #13
                          Originally posted by ELEGNT
                          build motor or keep ecu stock. simple
                          We'll see about the stock ECU, I think it's good for plenty more yet.

                          Comment


                          • #14
                            Debatable. Not until the assembly code can be further developed to increase the scalings without dodgy interpolation methods. Think alt maps and tephra big maps.

                            Sent from my GT-I9100 using Tapatalk

                            Comment


                            • #15
                              Originally posted by colTwes View Post
                              great stuff
                              maybe add to the list not to load the engine to much in higher gears+low rpm, most will allready know but not the newbies
                              also, where is the fuel pressure regulator? any pics?
                              Done - pics added.

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