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4EFTE Knock Sensor Placement and Power FC Tuning

General Tuning Discussion

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A few questions I hope you guys can help with. I am a gold member and have been working through the courses. I really need to get a build thread up also!

I have Datalogit and am logging AFR from my innovate MTX L wideband output. The car was an auto coverted to manual so it is running the variable tps although im not sure this will work/read the variable signal as the stock tps is just open/closed? So far Ive scaled Larger rx8 yellow injectors and input the lag vs batt voltage data from an rx8 website.

- I took 5 degrees ignition timing out of the whole map as im running 8.4:1 compression ratio and the numbers looked rather excessive for a tiny boosted engine?

- The car does run a bit lean after its heat soaked/hot restart although the stock compensations look ok

- The idle and cruise part of the map from stock(even with stock injectors) was quite lean and were no where near the rich INJ map which i am using as a target AFR table

- The numbers in the stock base map table in the idle and cruise areas are not linear as the revs increase, they seem all over the place. Is this normal?

- The engine is a fresh build so is only running in on 6 ish psi boost and the AFRs are good.

Any ones experience with the power FC on 4EFTE would be much appreciated

Does anyone have experience on a good place to mount my bosch knock sensor on a 4efte? I bought myself a Phormula Knock analyser kit and have mounted it into an m8 hole about 3 inches below the factory sensor. This was just so I can start listening to my engine and start listening for knock to back up the knock sensing in Power FC. I am finding it tricky distinguishing what is engine noise and what is knock. From listening to samples my understanding is that its a sharp tick noise that doesn't necessarily follow an rpm rhythm like engine noise?



Hi Dan,

Your sensor location is one of the better ones, I usually end up with it bolted to the head when tuning due to restricted access on customers cars. Have you tried inducing knock on light load at all and had it confirmed on the PFC?

The numbers in the table can vary depending on which display option you are using, personally I stick with correction as the AFR and Lambda values never match up with the real figures.

you are saying that the compensations look ok but the sensors are telling you different if they are ending up lean, sounds like it needs a little extra fuel when it gets hot

Thanks for the reply Chris. I have managed to get the idle and cruise part of the map close to 14.7 by using recalc base and just making percentage corrections this time around. I've also managed to get the intake temp corrections on target by adding a bit more fuel like you said but up to a certain point. Above 50 degrees after letting it heat soak for a while its still running lean even if i make a drastic change in the compensation table.

Once Ive got this sorted i will try adding some timing at light load and see if i can hear det