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400kw Gtr Fuel/tune Issue

Travis Trayhern

By Travis Trayhern,
in Engines & Forced Induction

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DVS JEZ Grand Master

DVS JEZ

Posted
Posted

My car blows black smoke on the dyno too. I run mine at 11.6 afr on 18.5psi.

U must remember even 12 is a rich mixture to help keep the combustion chamber heats down a little. So of course there will be smoke from incomplete burning.

The only thin i want to know is how the hell ur tuner can get a ruler straight afr line. That looks too suss unless he has high data smoothing on when he printed the sheet out

simpletool Mentor

simpletool

Posted
Posted (edited)
Polished combustion chambers cause less atomisation hence the 12:1 AFR and exess soot. Seen it on many cars with polished combustion chambers. The sards wont give you great atomisation either.

Ahh....so you're saying you end up adding more fuel than is typically needed to consume enough oxygen to get a 12.0 reading on the O2 sensors. The extra fuel just causes smoke as it's not a fine enough dispersion to burn properly - especially with the sards. Perhaps a higher rail pressure would help him? Or does this not help with Sards? Any experience?

Edited by simpletool
Travis Trayhern Proficient

Travis Trayhern

Posted
  • Author
Posted
Ahh....so you're saying you end up adding more fuel than is typically needed to consume enough oxygen to get a 12.0 reading on the O2 sensors. The extra fuel just causes smoke as it's not a fine enough dispersion to burn properly - especially with the sards. Perhaps a higher rail pressure would help him? Or does this not help with Sards? Any experience?

hmmm all very intresting indeed. i will open the plugs up to a 1.0

in saying that 12.0 is still abit rich what should i be looking for.

Mad-Max Apprentice

Mad-Max

Posted
Posted
hmmm all very intresting indeed. i will open the plugs up to a 1.0

in saying that 12.0 is still abit rich what should i be looking for.

well im no turbo expert but from what i can see it very much sounds like a fueling issue....

if your gap/spark is fine with no missing id be looking at the fueling system as its sounds like the sards have a bit of a problem with atomisation and 800cc sounds pretty huge to me.

have you/the tuner been able to lean this out at all?? could be that the injectors are too big

one good way to check the spark is to either unbolt or get another cas and spin it with the plugs out earthed to the engine and have a look for yourself.... this gives you the chance to sort this issue out i know how much of a bastard it can be!

id say 1.0 gap or .09 should be fine tho.

femno Grand Master

femno

Posted
Posted

FARK ME so many damn keyboard tuners! Awesome!

What does your tuner suggest the problem is? Does he think there even is a problem?

What EXACTLY changed since it started making the smoke? Start looking there.

T04GTR Grand Master

T04GTR

Posted
Posted

so this black smoke, has it just started with this build or has it just happened out of the blue? you could check your duty cycle on the injectors at the point it starts blowing soot.

and try playing with the injector end angle aswell. mayby you have got a unevan mixture (black smoke) because the injectors are squirting on an open valve and not a closed one..

another idea is to crank up the fuel pressure to reduce the duty cycle and improve atomisation. you have an 044 so 65-70psi base pressure is fine!

Travis Trayhern Proficient

Travis Trayhern

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the tuner and myself have exhausted all options and cant work it out.

we are pulling the injectors out to get cc just to check there all flowing the same.

car was running fine prior to turbos being repaired.

was doing some maintance and noticed my comp wheel on both turbos had some wear on the blades, so took of and had comp wheels replaced. when i was putting turbos back on a few things changed,

-std bov removed and replaced with blitz atmo bovs hole blocked in intake.

-catch can changed to a filter and pipe to intake removed and blocked

-HKS twin power ignition installed

trailer the car to dyno because after reinstalling everything noticed it running rich.

so there just for a quick touch up re-tune.

car is making power no power loss at all 360awkw@6500 straight up and running good afr's 12.5 -12.0

the car is just bellowing out black smoke and alot of it.

so what will cause good afr's readings but clearly excess fuel coming out without showing on the afr metre?

tuner is not comfy leaning it out anymore as there is clearly something up with the amount of smoke coming out.

Travis Trayhern Proficient

Travis Trayhern

Posted
  • Author
Posted

so there has been no power loss, actually getting a faster spool up by 500rpm when compaired to my last tune

afr are reading good 12.0 12.5

just shit loads of black smoke

femno Grand Master

femno

Posted
Posted

I have no idea how the HKS Ignition System works but spark is directly related to this issue. Does it have full voltage to it?

Try splitfires and standard ignitor etc. Back to basics. Its a longshot, but possibly the IGN system is faulty and not burning all the fuel that is going in, but burning just enough to make the power, and blowing the unburnt fuel out the back.

The AFR meter will only read burnt fuel.

I cbf reading above but how is INJ duty compared to the last tune exactly?

If higher than last time more fuel is going in, but if its making the same power and running the same AFR as last time, somethings up.

STATUS Grand Master

STATUS

Posted
Posted
I have no idea how the HKS Ignition System works but spark is directly related to this issue. Does it have full voltage to it?

Try splitfires and standard ignitor etc. Back to basics. Its a longshot, but possibly the IGN system is faulty and not burning all the fuel that is going in, but burning just enough to make the power, and blowing the unburnt fuel out the back.

The AFR meter will only read burnt fuel.

I cbf reading above but how is INJ duty compared to the last tune exactly?

If higher than last time more fuel is going in, but if its making the same power and running the same AFR as last time, somethings up.

yeah, i reckon it probably the TPI, i would run it without it like i posted above.

  • 4 years later...
crashsvg Contributor

crashsvg

Posted
Posted

i cant say for sure,,but i had some sard injectors 900 cc and the second i put them in they fowled my plugs..could not get the car idling much less tuned..had me doubting my tuning skill for a while lol..... replaced them with stock problem went away..i later installed some dw injectors..

those sard injectors seem to be a hit and miss imo

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