[kiler07]

Hello everyone
My car bmw e92 n55 PWG with upgradeturbo.
21.5psi tappering to 18psi at redline, 7-8* timing advance.
My tuner recomanded ngk 97506 plugs with 0.018" gap.

On 0.018" gap : once is perfect


once is horrible:


I had problem with my idle rpm on 0.018" then i tried stock gap on new plugs - idle was ok, low/mid load was ok but on WOT multiplemisfire:


On cyl3 i have bigger correction from other cyl's, why i should do now ? Now i have 0.022" gap, on 50-70% throttle had -8*correction on cyl3 (not always but still), tried swap coils with other cyl, still correction on cyl3.
Maybe my injectors going died ? On coldstart sometimes i hear popcron from my exhaust (a little misfire, specially on 0.018"Gap, on stock less). I can replace one injector (cyl3) to test ? Or just swap injectors with new gasket and if correction will jump to other cyl then replace all ?

Thanks

[Kevin39]

Can you post the data log?

[Tunafish]

You should provide the datazip files for help.. Your logging should start in 3rd gear at 2500 to 6500 with traction control off and floored with shift into 4th held for a couple of seconds..

Without a log then we can make uneducated guesses all day long.. But with the little information you have given i going to say octane is the issue. There has not been many injector failures in the n55..

[kiler07]

https://datazap.me/u/kiler07/

https://datazap.me/u/kiler07/04b-4c-2?log=1&data=4-21

On my profile a lot of logs, 0.4b is current map.


IC wagner evo 3
DV Gfb+
DP 3"
BMS intake
98RON fuel
105k km mileage

[Tunafish]

The one log you provided looks good except cylinder 5 on the 3rd gear pull (didnt look after this since there are little reference points).. Check the plug.. Shouldnt be throwing the codes you have though..

[kiler07]

Originally Posted by Tunafish

The one log you provided looks good except cylinder 5 on the 3rd gear pull (didnt look after this since there are little reference points).. Check the plug.. Shouldnt be throwing the codes you have though..

When i change my turbo, then install ngk 97506 with 0.018" gap. Had a hestination on low/mid load but on WOT once perfect, once horrible and i saw this on times 100-200 when logging. Once 8.4s, second time 8.9s, power isnt stable.

Then i bought new plugs 97506 and plug with stock gap - result, multiple misfire, check engine etc. Now i have 0.022" - same thing, 50/70% throttle, 1/1.2bar boost and i see -6/-8*corettion on cyl3.

What i should try now ? Stock plugs? Replace injectors ? On logs hpfp is strong, coils have 28kkm, new plugs.
On facebook group they recomanded stock plugs with stock gap. My tuner recomanded replace injector cyl3 and stay with ngk 97506 0.018" gap.

[Tunafish]

Like i said before.. Its octane 98 ron is the same as 93 octane.. That will support upto 18psi depending on outside temp..

You need to increase your octane or decrease your boost or decrease your timing.. You can throw parts at it all day long but without the right fuel you will be throwing that money away..

If you cant source better fuel, then methanol will help and is a option to boost octane ..

[kiler07]

Originally Posted by Tunafish

Like i said before.. Its octane 98 ron is the same as 93 octane.. That will support upto 18psi depending on outside temp..

You need to increase your octane or decrease your boost or decrease your timing.. You can throw parts at it all day long but without the right fuel you will be throwing that money away..

If you cant source better fuel, then methanol will help and is a option to boost octane ..

hmm interesting, my tuner tell me this timing isnt hard for 98ron fuel, and this boost.

How much ethanol i can add to tank to boost octane ? E15/20 mix ? (fuel has 10% alcohol)

[Tunafish]

I think e30 is the max for stock fuel pump but this will be the weak point on running e and will have to be monitored.. By the one log that I seen it was a cool day at 48f and didn't see any issues except for the number 5 plug..

This didn't cause the errors you have and I haven't seen a log of major timing correction. If you would like to provide we could get an better educated guess..

With the info I have I know that 18psi is generally considered the limit with the type of timing you are running, and assume that the logs that gave the timing correction to throw the codes happened on a hotter day which will show if you are on the edge of your octane limit. Again this is assuming with the information provided. I see no issues with the one log you posted expected cly 5 which is probably plug.

[kiler07]

But 18psi from stock turbo compare to upgrade or swap big turbo it not the same.

stock gap, 1 pull, multiple misfire, screenshot post before
https://datazap.me/u/kiler07/cel?log=0&data=4-21

0.018" gap, all perfect, car makes 8.4s 100-200
https://datazap.me/u/kiler07/04b-4c?...48-49-50-51-52

0.018", big correction cyl3, car makes 8.8 100-200
same weather condidtion like up, its log after log with 2-3km slowly drive on highway
https://datazap.me/u/kiler07/04b-4c?...48-49-50-51-52

Few days later i make again 100-200 and once 9.2s, after 8.5s, same point shift etc.

Sometimes when i hard pull from 2gear and shift 3 gear - misfire (car shift like m4 or m2, shot to exhaust hard), sometimes before redline - no codes or etc after that, its effective and nice but not healty to engine

[Tunafish]

Yeah 18psi is 18psi no matter where it comes from.. But looking at the two logs only thing I notice is stft is adding fuel when you have the timing corrections which would make sense the cars shutting off the injectors making a lean connection.. I still would boost the octane before changing out any parts..

[kiler07]

How i can boost octane ? I have acess only for 100RON fuel or add some ethanol to tank. The octanebooster is shit i think.

[Tunafish]

Run 100Ron that should do.. Log and see.if it makes a difference..I think you are right at the edge so the extra 2 Ron might be enough.

[kiler07]

Tomorrow i can tank 100ron fuel and 10L ethanol, that will be around e25 mix with 100ron fuel. Or just mix with 98ron fuel ?