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4G93T MBT?


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So engine is a built 4G93T no cams.

1.8L stroker to 2.0L

Fuel : RON 98


Maximum boost 1.5bar or 150kpa absolute pressure ,250kpa from vaccum.

IGNITION AT 7200rpm 1.5bar is 7 degrees.

The vehicle at peak torque having 7-9 degrees advance ign vs the vehicle at peak torque 4-5 degrees at 4000-5500rpm feels like with less timing it has much much more torque and is dramaticaly noticed.The ignition is correctly locked so no offset.Why is this happening will attend to fine tune on a dyno so i am asking just to know whats going on right there.Is it possible to reach MBT with this type of fuel? The a/f is 11.5 after 1 bar. 

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I have never work with that engine before but I'm guessing is like a EVO engine, in that cause we have 97RON fuel here and I have never reach MBT at that pressure with that fuel, I would need a meth/water injection or something else. But the dyno will tell the story, if running less timing make more power be careful cause it could mean you have knock with the old map that have more timing (I dont know if you are running any type of knock sensor on your setup), if it is a stock ecu sometimes I have found that running to much timing make the sensor pickup knock and retard the all ignition map and make the car actually slower that a ignition map with less timing and no knock.

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Hello there, here is my timing map i am running on LINK ECU. Having an external knock control (plex monitor).

The problem is that sometimes picks up knock and i don't know if it is actually knocking


And here is the theoretical timing i made with calculations. Thermodynamics and Internal combustion engine.


The theoretical looks correct for me but i haven't try it yet. What should i do?

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So are you measuring power/torque on a dyno to come to these timing figures, or guessing ?


And detonation is easy....listen. Your Plex offers you headphone sockets for this purpose, as well as the electronic/visual aspect. If this isnt ok, then plain and simple old manual det cans are extremely effective.


Run it on the dyno and listen.

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I am guessing ,the main problem is i can't seperate knock from engine noise ,hydraulic lifters make a lot of noise i try seperating them from the actual knock but nothing sometimes it picks sometimes it doesnt.

Are you familiar with plex units? 


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5 hours ago, Fotis said:

problem is i can't seperate knock from engine noise ,hydraulic lifters make a lot of noise

Hydraulic lifters should have zero lash and be near silent.  If they are making that much noise you cant hear knock then there is either something wrong with them or the rocker geometry or cam profile.

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