Questions to those who map.

RX7 · Post by **RX7** » Sun Nov 08, 2009 3:25 pm

Got my datalogit that plugs into my Apexi Power FC ecu this week.
I have the innovate LM1 for the wideband with the clamp holding it in the exhaust.

Tried to do some runs through the rev ranges at different throttle settings as on full throttle it works fine but anything else when I try and go into the 2nd turbo it just stutters and the boost isnt smooth at all (there is a pause about 4.5k until 5k when the 2nd turbo kicks in but this is normal).

Sadly I couldnt do any 3rd gear runs but tried some 2nd and found that when it was logging on the map watch view (showing the AN1 - AN2 Wideband on Avg, 20msec hold off and 20 max value) and the ghost setting on it made some of the cells red but didnt put a figure in this. Is this because its out of the AFR range (mine is set from 9 through to 20) or because the logging cell wasnt there long enough to get a figure When I saved the log and reopened it the red cells have disappeared and there are no figures at all in them.

Second thing is when I did log the run today I noticed that a number of the cells are showing AFRs of circa 9.90. I am guessing this is massively overfueling and its in the cells from N14 and N16 on rows P08 and P09. Would this be a good assuption ? Am going to do some 3rd gear runs before making any adjustments, will this provide some better indications ?

Sorry am new to all this but loving it and working my way through the tutorials on RX7club.com. The amount of data it logs is phenomenal, Dunk all those mickey takes about you logging all the time.....I take them back now !!!

Cheers for any help,
Gareth

Gerry H · Post by **Gerry H** » Sun Nov 08, 2009 5:55 pm

Twin turbos and leading/trailing sparks, you'll be needing someone who's clued up on rotaries in a big way.

Datalogit is good software for the Apexi and light years better than the hand controller.

duncan · Post by **duncan** » Sun Nov 08, 2009 6:27 pm

Gareth - I would work at some set rpm/load points to start with to get the fueling right rather than trying to play catch up on a moving feast like a full throttle run. Especially 2nd gear runs happen so quickly that you cant do anything too precise with afr's - made even worse by the transport time to the tailpipe.

It helps if someone is doing the driving while you are doing this or if you can get it on the dyno to get to these points in absolute safety.

ScoobieWRX · Post by **ScoobieWRX** » Sun Nov 08, 2009 6:51 pm

Logging Rules!!

Doesn't take too long to analyse your logs when you know what you're looking at and deduce where you're having problems based on how the car feels when you''re driving it. Put your own natural driver logging together with the ECU logs you're pulling and you're away. Sounds like you're having fun anyway.

Sounds like the delay in one turbo kicking in as the other runs out of puff during part throttle is causing your overfuelling. There is in effect a flat spot for 500rpm worth of no increase in airflow even though there should be a constant increase of airflow as the changeover happens. The ECU is expecting x amount of air flow during the turbo changeover and squirts the correct amount of fuel in but there is not enough airflow due to this turbo delay to make correct AFR therefore you get a rich state and hence your 9.9:1 AFR.

Are twin turbo's not set up so that as the first one starts to run out of puff the second turbo is already kicking in so as not to cause a drop in air flow/boost?? Could be the turbo maps need fettling for seamless changeover at whatever RPM they are set to do that. Maybe try to map the second turbo to kick in sooner due to perhaps lag on the second turbo causing your 500rpm delay or try to get the first turbo to boost for a bit longer to give the second turbo a chance to kick in.

It's just a stab in the dark so I'm very probably completely wrong. I'll get my hat and coat!!

gary@apt · Post by **gary@apt** » Sun Nov 08, 2009 9:00 pm

gareth come and see me ill see if i can help you

duncan · Post by **duncan** » Sun Nov 08, 2009 9:15 pm

gary@apt wrote:gareth come and see me ill see if i can help you

Perfect call :thumb:

RX7 · Post by **RX7** » Sun Nov 08, 2009 9:37 pm

Cheers guys. I'll see about trying some 3rd gear runs at different throttle points and see what happens.

Francis, no you cant set one to spool up whilst the other is running out of puff. Sadly they dont work like that, on most peoples turbo maps there is a flat spot during the transition point.

Gary cheers for that, I will be ringing you this week to get the MOT booked in. Will come armed with the logs

ScoobieWRX · Post by **ScoobieWRX** » Sun Nov 08, 2009 10:08 pm

I knew there was a simple answer