BRZedit Cam Tuning Info

[mad_sb]

Greetings Everyone.

I managed to find another local dyno that charges much better rates than the last place i went.. so i decided to give them a shot today and work on some cam tuning. This is on my stock 2013 FR-s. I have just over 1,000 miles at this point and am still on the temporary tag No intake mods (other than sound tube delete), no exhaust mods etc. Just a catch can, opticoat, and a lazer jammer.

A little background to explain the test setup first. My car has seemed to run on the lean side since day one. After my first tuning session i noticed the WOT afr's were hit an miss.. sometimes they were spot on (right after a flash) sometimes they were too rich to register (richer than 12.1:1) on the factory wide range sensor. After doing a lot of logging it turns out i was stacking up heavy long term fuel trims (between +5 and +10). I believe this is a common issue with these cars and is most likely responsible for the aftermarket intake bogging issue many people experience.

Anyway. Over the past week i have rescalled my Maf to get the trims under control and made a few changes to the open loop transition setting so it drop into openloop based on the fuel map not any of the timers etc. This is a typical subaru setup found on latter model rex's and lgt's etc. I had not had time to dial in the fuel before the cam tuning and more details of the whole trims issue will be posted in another thread.

The base map i used for the cam sweep testing includes my maf rescale with several degrees of timing pulled out for safety during the testing. All pulls were done in 3rd gear to keep the run times short on my fresh motor

I started with setting the exhaust cam to the middle of the adjustment range (25 on BRZedit) and moved the Intake cam from full advance (40) across the whole rpm range to middle position (15) to full retard (-10)... here are the results:



Next I blended the intake cam settings based on the above to get the best power and moved the exhaust cam from full retard (0), to middle (25), to full advance (50)....



I then blended the exhaust cam setting and pasted the intake and exhaust cam maps into the map i drove in on. This map has not been tuned for power yet, just basic maf scaling with about the same timing curve i came up with last time on the dyno. Here are the blended settings vs the stock map with the advance multiplier set to 1.0.. this a good bit richer than stock...



Here you can see the comparison of fueling between the stock map on my car and run 11 from the above plot:



I had to get off the dyno at this point, but i did tweak the fuel to a consistent 12.7 - 12.9 wot before i left the parking lot for the drive home.

The dip is much less noticeable now and it pulls very hard from just over 4k. I think I am done tuning on the stock setup for now. I'm going to post up the maf scale info in another thread tomorrow. I'm sure there is more that can be pulled out of the setup by phasing the cams together in some spots (advancing or retarding them together).. I'll play around with that once i do some intake and exhaust work.

[Jesse]

thanks for the post, good work

[efactor84]

Seems like I need to get myself BRZedit too, instead of canned tunes like ECUTek and Unichip.

[arghx7]

Please post screenshots of the actual cam timing maps you used--before and after. They're 3D lookup tables, and when you say you fixed them at a certain value it's not clear what that really means.

Please post logs of your pulls so we can see how you changed the open & closed loop transition. The delay timers are for fuel economy & emissions, so yes there's potential response and torque to be gained by changing them.

[mad_sb]

Originally Posted by arghx7

Please post screenshots of the actual cam timing maps you used--before and after. They're 3D lookup tables, and when you say you fixed them at a certain value it's not clear what that really means.

Please post logs of your pulls so we can see how you changed the open & closed loop transition. The delay timers are for fuel economy & emissions, so yes there's potential response and torque to be gained by changing them.

Closed to Open loop along wtih maf scaling with be another thread.

I can post screen shots of the cam timing tables but essentially from 80g/rev and up i just pasted the stated values for teh above testing. On the dyno you go wot as soon as you start the pull and load jumps up to 1.0 or higher. Afterwards I smoothed out and blended the transitions from lower load to the final values in higher load.

[86drift]

Nice work. I look forward to seeing your post about the fuel trims.

[mad_sb]

stock cam timing maps:


Fixed Cam Timing Example:


Final Cam Timing Maps from this session:

[arghx7]

Thank you for posting these. I'm curious about the units for the exhaust cam timing map. The normal strategy is for the AVCS to be retarding the closing timing of the exhaust valve, thus increasing overlap. However, the units are positive for the exhaust side. Does a higher # really indicate more advanced timing? It depends how the software is written. All the Subarus I've tuned had only intake AVCS, so I never paid attention to how the exhaust cam phasing maps were set up.

Now, if only we had cylinder pressure + intake and exhaust pressure transducers. Then we could see what's really going on with the scavenging effects and blowdown pulses.

[sierra]

Great work! It makes you wonder where this motor will end up getting power wise NA?
I love it almost stock and it gives me a real buzz but my old ticker can handle more.
Bring it on!

[Xero-Limit]

You're going in the right direction here. I would recommend trying smaller increments as you get time; a few degrees can make a difference. When you're making these changes bear in mind the timing of the fuel and the spark as well. You're now changing the point of the combustion cycle at which you have greatest overlap (and the amount), but that may no longer be the place at which you'll develop best torque if you spray the fuel and fire the spark at the stock points. Keep this in mind with the AFR as well--when overlap gets extreme power will not always be at a theoretical 12.7 AFR.

[mad_sb]

Originally Posted by moto-mike

You're going in the right direction here. I would recommend trying smaller increments as you get time; a few degrees can make a difference. When you're making these changes bear in mind the timing of the fuel and the spark as well. You're now changing the point of the combustion cycle at which you have greatest overlap (and the amount), but that may no longer be the place at which you'll develop best torque if you spray the fuel and fire the spark at the stock points. Keep this in mind with the AFR as well--when overlap gets extreme power will not always be at a theoretical 12.7 AFR.

Appreciate the tips , I am aware the cam timing changes required fuel and spark as it affects cylinder fill and dilution, but admittedly i had not given a lot of thought to the best power afr change due to overlap.

Paying for dyno time sucks I could have spent the whole day just tweaking cam timing. Anyway this gives the other BRZedit guys a place to start from and then tweak. My intake and overpip / front pipe should be here next week so I'll be back to the dyno again before long.

[diodelphi]

my stock car has 10% LTFT .
if i plan to go for stage 2 (changing the header , front pipe and catback) should i rescale the maf before going to stage 2 tune?