RX8 Performance Turbo Build
02-03-2016, 10:19 PM
#79
I think over the summer I'm going to see if I can't get my hands on an adaptronic ecu and make use of the MAP sensor it has. The car runs fine with the cobb but the 9000 foot long intake path with the maf at the front kind of has me bummed over throttle response and closed loop operation (more oscillation of AFR fuel trims constantly over/under compensating than I'd like to see).
1) Hunting down and correcting even the smallest of vacuum leaks as much as possible
2) Getting the P1 injector sizing dialed in to +/- 2% STFT steady state (I still get random highs/lows now and then but they are the exception)
3) Bump up the idle to 1000RPM
It will swing up/down a little briefly when coming to a stop and then it is pretty rock solid worst case within +/- a few AFR points, ie: 14.5-14.9. Turning on the AC or other accessories like the rear defroster or HIDs that increase engine load will make it just a tad worse briefly but it will settle down, just takes slightly longer...
Once this was done I worked on the MAF calibration in the closed loop areas and I have very little STFT anymore and nice cruise results.
Also +1 on Brettus suggestion for a honeycomb.
Last edited by slash128; 02-03-2016 at 10:42 PM.
02-04-2016, 08:31 AM
#81
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I have a long intake and initially had fairly severe AFR oscillations at idle. I all but eliminated it by:
1) Hunting down and correcting even the smallest of vacuum leaks as much as possible
2) Getting the P1 injector sizing dialed in to +/- 2% STFT steady state (I still get random highs/lows now and then but they are the exception)
3) Bump up the idle to 1000RPM
It will swing up/down a little briefly when coming to a stop and then it is pretty rock solid worst case within +/- a few AFR points, ie: 14.5-14.9. Turning on the AC or other accessories like the rear defroster or HIDs that increase engine load will make it just a tad worse briefly but it will settle down, just takes slightly longer...
Once this was done I worked on the MAF calibration in the closed loop areas and I have very little STFT anymore and nice cruise results.
Also +1 on Brettus suggestion for a honeycomb.
1) Hunting down and correcting even the smallest of vacuum leaks as much as possible
2) Getting the P1 injector sizing dialed in to +/- 2% STFT steady state (I still get random highs/lows now and then but they are the exception)
3) Bump up the idle to 1000RPM
It will swing up/down a little briefly when coming to a stop and then it is pretty rock solid worst case within +/- a few AFR points, ie: 14.5-14.9. Turning on the AC or other accessories like the rear defroster or HIDs that increase engine load will make it just a tad worse briefly but it will settle down, just takes slightly longer...
Once this was done I worked on the MAF calibration in the closed loop areas and I have very little STFT anymore and nice cruise results.
Also +1 on Brettus suggestion for a honeycomb.
02-04-2016, 09:40 AM
#82
I have the basic AEM boost gauge/EBC combo gauge, which works enough to get the turbo running haha. An actual EBC is definitely in the acquisition pipeline of the future.
I have a long intake and initially had fairly severe AFR oscillations at idle. I all but eliminated it by:
1) Hunting down and correcting even the smallest of vacuum leaks as much as possible
2) Getting the P1 injector sizing dialed in to +/- 2% STFT steady state (I still get random highs/lows now and then but they are the exception)
3) Bump up the idle to 1000RPM
It will swing up/down a little briefly when coming to a stop and then it is pretty rock solid worst case within +/- a few AFR points, ie: 14.5-14.9. Turning on the AC or other accessories like the rear defroster or HIDs that increase engine load will make it just a tad worse briefly but it will settle down, just takes slightly longer...
Once this was done I worked on the MAF calibration in the closed loop areas and I have very little STFT anymore and nice cruise results.
Also +1 on Brettus suggestion for a honeycomb.
1) Hunting down and correcting even the smallest of vacuum leaks as much as possible
2) Getting the P1 injector sizing dialed in to +/- 2% STFT steady state (I still get random highs/lows now and then but they are the exception)
3) Bump up the idle to 1000RPM
It will swing up/down a little briefly when coming to a stop and then it is pretty rock solid worst case within +/- a few AFR points, ie: 14.5-14.9. Turning on the AC or other accessories like the rear defroster or HIDs that increase engine load will make it just a tad worse briefly but it will settle down, just takes slightly longer...
Once this was done I worked on the MAF calibration in the closed loop areas and I have very little STFT anymore and nice cruise results.
Also +1 on Brettus suggestion for a honeycomb.
I do have a honeycomb before the maf in a nice straight section of intake (about 10" long).
All in all my closed loop AFR's are in the 14.4-15.0 range so I'm not too far off your standard lol. Guess I have some more work to do!
02-04-2016, 12:43 PM
#83
Disco .... it really sounds to me like you could be worrying about nothing . If the engine is hesitating etc , get back to me and we can work on it .
If you think you can make use of some of the neat features the Adaptronic has then I can see why you would want to change . However ,there has not really been any discussion on here that has shown these features are woth having yet ....................to my knowledge.
As far as throttle respose goes ..... I don't really understand why you might think another ECU might make it any different than it already is. Can you clarify ?
If you think you can make use of some of the neat features the Adaptronic has then I can see why you would want to change . However ,there has not really been any discussion on here that has shown these features are woth having yet ....................to my knowledge.
As far as throttle respose goes ..... I don't really understand why you might think another ECU might make it any different than it already is. Can you clarify ?
Last edited by Brettus; 02-04-2016 at 01:29 PM.
02-04-2016, 06:44 PM
#84
Its more of a "grass is greener on the other side" issue than an actual issue haha.
I'm just curious to see if the adaptronic makes it any quicker to respond than current state (which by most standards is still really good). The MAP sensor is what has me the most curious and how that will affect operation as well as ease of tuning.
I'm just curious to see if the adaptronic makes it any quicker to respond than current state (which by most standards is still really good). The MAP sensor is what has me the most curious and how that will affect operation as well as ease of tuning.
02-05-2016, 11:31 PM
#91
Driving my unreliable rx8
Same here I've reduced max throttle opening and averaged the tables. Since I see positive pressure around 25-30% theottle. That gives better part throttle control.
02-07-2016, 11:52 AM
#93
It should, aside from the fact I have nothing to log boost with and there's no RPM compensation for loss of boost up top. So its gotta be done manually (by eye or video tape and and play it back in conjunction with cobb data) and adjust for peak boost. Which isnt a problem, as that's what I've been doing all along. Upping the wastegate spring, a 4 port solenoid, and then re-tuning the controller would definitely help reduce turbo lag for sure.
02-07-2016, 12:42 PM
#94
It should, aside from the fact I have nothing to log boost with and there's no RPM compensation for loss of boost up top. So its gotta be done manually (by eye or video tape and and play it back in conjunction with cobb data) and adjust for peak boost. Which isnt a problem, as that's what I've been doing all along. Upping the wastegate spring, a 4 port solenoid, and then re-tuning the controller would definitely help reduce turbo lag for sure.
does it have a 'start boost' setting ? IE. a setting that prevents the WG opening till it gets to that psi .
That is the setting that will improve your turbo response . It should be set just below target boost so that you don't get a spike.
Also .... you can log boost , to a point , with a load vs rpm log .
Last edited by Brettus; 02-07-2016 at 12:56 PM.
02-07-2016, 02:32 PM
#96
Dark Moderator
iTrader: (18)
It was recommended by Brettus, researched by me. Approved by all it seems lol.
Travis
02-08-2016, 01:50 PM
#99
If I set the crack pressure to a desired level (lets say 7 psi) but I only have a 5 psi spring in the waste gate, the boost will oscillate as the controller over compensates because its derivative setting is way too big. The actual settings vary as you can fine tune the crack pressure setting for a quicker spool but not too much oscillation, it becomes a trade off at some point.
The aem set up is super basic and it works to a point. To get into the fine tuning of boost profiles I'll need a smarter controller.
Last edited by discotech; 02-08-2016 at 01:52 PM.