Hi guys,

Quick rundown, I've got a 4G93T in my Lancer GSR, TD05-16G turbo, Evo 7 ECU, MAF, and injectors.
I use an OP2.0, and have a PLX wideband to watch the o2 stats (cant log it).

At the moment I'm running the standard Evo 7 JDM Fuel/ignition map.
The engine runs perfectly fine when you're thrashing it. WOT on 25 pounds of boost, never had a problem. However one issue I've never been able to fix is how easily it knocks in a particular situation.
The situation in question being, coming out of a tight corner (say, a 90 degree turn through a roundabout), you shift down to second, go through the turn, and plant it on the way out (maybe 3000rpm in second or so). And as soon as you start to open that throttle, not only does it not accelerate and feel sluggish, but the CEL flashes like crazy and it generates bucketloads of knock.

I've tried adding a bit of fuel and pulling some timing, but it didn't seem to make any difference.

Any ideas what causes this?
If you need any more info just ask

 

I dont know how the gas tank and fuel pump is set up in the 9's. I own an X. But the X's have a similar issue where the fuel pump cannot get fuel in it during a turn because the fuel has sloshed to one side of the tank causing the fuel system to suck vapor and lean out the combustion.

Does this happen on a full tank?
Can you log your afr or oxygen sensor voltage during the turn?

 

unfortunately I havent been able to log the PLX Wideband.
I need to figure out how to log the aux jack on the OP2.0, then write a formula for the PLX WB.
But, the AFRs drop like a stone. Ill double check tomorrow, but I dont think it's the cause.
My GSR is a 1995 CC chassis Lancer, the fuel tank has an internal baffle around the tank, and when you go WOT the rail return will close to keep fuel pressure at the injectors high, so I doubt I'm having fueling issues :/
Thanks for the idea though
And yes, it happens all the time

 

So are you transitioning from fuel-cut to WOT at the time when the knock occurs?

 

I think so. I was wondering if this could cause an issue.
The only way to accelerate out of a corner (after being on fuel cut) is to ease into it. If i gently press the accelerator for a couple of seconds, bring the revs up to say 4,000. THEN go WOT, it's fine and dandy haha

 

That was my next question if you still see knock when easing into it....
Here is my guess since we don't have data yet, but the rush of air when transitioning from fuel-cut to immediate WOT, may be causing lean combustion resulting in knock. I know in aftermarket ecu's they typically have a calibration that is a function of rpm and throttle rate so you could add more fuel to accommodate for sudden changes in the air volume.
Are you able to add more fuel in those load/rpm areas and note any difference?

 

I can certainly try it.
Will need to log some cornering/WOT transitions and add fuel in the effected cells
How much fuel would you expect to make a difference? I'm not sure how much is too much/not enough..

 

I did some quick testing.
If im in second, at ~2500rpm, and I go to WOT, the AFR drops to 10 (plx wideband doesnt read any lower). Once it gets to the high 3000's, and starts to come on boost, it pings like crazy.
That would be caused by too much timing advance right?

 

possible!.... without data we're just guessing

 

I really need to find out how to log the PLX Wideband with the OP2.0 :/
I made up a two pole 3.5mm to 2.5mm wire which plugs into the TX port on the PLX and the 2.5mm port on the OP2.0
Problem is, I havent got a clue what I need to do to be able to log from that. I'm no good at writing code etc etc