13b rew Single Turbo tuning - misfire under low load
 

Hello!

I have recently finished my single turbo conversion and started the mapping. Did some low load pulls on the highway tonight and noticed a few issues with misfires. The engine runs fine from 2000 rpm to 3500-4000 where the turbo starts spooling. When the turbo starts to spool is when i get the misfires. The AFR is 10.5-11 in that range.

Note that this is under low load and very little throttle. Super low knock readings too (0-1).

Im thinking at bad coils and spark plugs. Or maby its running to rich in that area?

Engine specs:

13b REW
Stock porting
2 extra dowelpins in every housing and plate
3 mm, 2 piece rotary aviation apex seals
Solid corner seals
Premix 1,5 % with blocked OMP
Balanced rotors,e-shaft and clutch
FMIC
Stock coils
TB70 turbo: 70 mm inducer on compressor and 75 mm inducer and 1,15 A/R on hot side
Brand new sparkplugs BUR9EQ
850cc pri and 1680cc sec injectors
3,5" DP
60 mm wastegate
Apexi power fc with datalogit

Before i started the car up a few weeks ago i checked all the sparkplugs, coils and spark plug wires and they was working fine.

Maby it is the settings with the injector overlap and transition for the secondarys?
Currently running pre/sec transition = 40% and transition (ms) = 1,500

In my opinion the car would run fine at AFR 10,5-11 on low load without misfire.

You have to excuse my poor english but im from Sweden :nod:

Best regards

Olle Lindén

Olle,

Welcome to the forum. Your English is actually better than some of the native US people that post on here looking for help. How sad that is...

Anyway... I am going to move this thread to the Power FC forum as most of the tuners hang out there. I'm also changing your thread to provide a little more info.

Good luck.

Right when your turbo's come online you break past the 40% injector duty cycle and the secondary injectors kick on typically. Given the fact that you have 1600cc's for secondarys it sounds like you could fair to lean it out a bit in that area of the injector map. What is your leading timing and timing split in that area of concern?

If you don't mind post your map.

ive discovered a different error with the whole car that causes the missfires. the engine is leaking oil from the rotors in to the combustionchamber. this is what causes the missfires. The engine can't burn the exessive amount off oil that leaks in. i will pull the motor next week and have a look. It seems to be the front rotor. the sparks are oily on that one and are normal on the rear one.

check my other thread in the 3rd generation archive to see the whole problem. Search for "heavy smoking 13b rew - need help!".

Thanks for all help anyway!

Best regards

Olle

Those injector transition settings are not going to work well with your injectors though. You are right about that.