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Optical

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Posts posted by Optical

    Twin scroll garrett fail

    in Engine Related

    Posted

    On 5/06/2019 at 7:36 PM, Loren said:

    I think the 0.82 would be too laggy for me... probably really good for a track car though.

     

     

    Interesting thread Loren! Did you end up with a divided or single entry uppipe flange?

    I remember RAC doing tons of testing years ago and ended up somewhere similar to where you are now.

     

    I made the .82 choice years ago when Tony had a 0.63, or some aftermarket 0.72 size housing he found. Compared to Tony's car, my 82 housing was bogging in third on tight corner exits and didnt provide enough top end to make up the difference on the straights, so i'd drop back about car length on every tight corner which added up to 2-3 seconds/lap. So it was either shift to second gear and lose time on the 2-3 shift, or bog in third. The 63 was faster simply by being able to stay in third. So I went back to the 63...

     

    • Like 1

    EJ25 Hybrid questions...

    in Engine Related

    Posted

    Ive been running a stock 257 shortblock with EJ20k/v4sti heads for nearly 10 years at about 260kwatw.

    This engine hates small turbos. Also not having boost is not as dramatic as on the 2L as the off-boost torque is so much higher. The engine likes a big turbo (bigger than a VF anyway) but ~400bhp is about the limit. This engine has also done hundreds of track laps, as long as you keep at least oil temps down it seems to be pretty happy.

    • Like 4

    VF34 upgrade options

    in Engine Related

    Posted

    A friend of mine (QWERTY on here) has a bolt on turbo he used to use lying around. Was making about 260kwatw

    Cant remember exactly what it was but i'll send him a message. Was one of those popular a while back turbos based on the small trim GT30r wheels. MD321 perhaps?

    Link G4+ onboard knock setup

    in Electrical

    Posted

    Datalog the S*** out of your engine and it will give a pretty good profile of your baseline noise when the engine is known to not be knocking. The Link knock system is based on filtered signal amplitude and rpm, so if you have a baseline noise profile across the rpm range then anything spiking above that is considered knock and you can do something about it like retard timing, drop boost etc. Whether it is knock or not is another question - sometimes it is, sometimes it isnt and the ECU cant tell the difference. Just have to know your engine noise levels well enough to make a decision on what to do.

    Average Torque Performance Tune?

    in Engine Related

    Posted

    It's pretty close to linear. I'm in the process of tuning my flex fuel setup... Process has loosely been:

    Complete 98 tune

    Add 30% to 4D fuel map and 4* to ignition 4D map at 85% alcohol, interpolate tables back to zero%

    Add 20 alcohol to tank, tweak fuel and ign maps

    Add 40% alcohol and tweak

    etc

    EJ20G running like ****e

    in Engine Related

    Posted

    Can weld it

    The key isn't supposed to take any load - it's job is primarily to align the crank sprocket trigger to the crank. The pulley bolt when done up tight clamps the sprocket to the crank nose

    I'll have a go at fixing it at least!

    EJ20G running like ****e

    in Engine Related

    Posted

     Optical said:
    it appears the ECU is pulling all the timing out of the engine.

    Well I finally figured this out and it aint pretty.

    Indeed the timing was being pulled out - due to the crank pulley bolt being loose and the woodruff key taking the crank sprocket load. Keyway in the crank nose is flogged out and woodruff key munted. Result is around 20 degrees lag between crank and cam timing and resultant cam trigger timing.

    13020372_10154155065631518_1920081284_n_

    EJ20G running like ****e

    in Engine Related

    Posted

    Thanks for input guys

    Engine was replaced a while ago with a lowish mileage one which seems healthy. I also put the ej20k ignition system into it so spark is healthy at least. Never a single misfire or similar (was terrible on the old ej20g coils)..

    Intake pipe has already been plugged up and crank case breather system doesnt run into the intake any more. IAC hose is new and leak free.

    I did have a fault code 43 - pressure exchange solenoid and map sensor arrangement. Map sensor wasnt plumbed to pxs right so have sorted that and cleared the code. Still behaves the same...

    Could be an air leak, Idle doesnt hunt and I cant see anything obvious.. I will check the pipe under the IC - IC is a bit wobbly so maybe it has flexed and cracked. Then onto the AFM, should be an easy swap with someone to check. Im hoping it's simple something like that!

    Seems odd that it pegs at 4000rpm though, i'd have thought the ecu would be causing that, but without a fault code it's hard to know.

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