Sorry guys, It is pinned. Nice thread.



Mike, how did you come up with the right fuel ratio on the diagram?

 

You should fit an EGT probe as close to the exhuast port pre-turbo exhuast housing as poss.



I have had it pre and post on my Impreza, but just going through all the same tuning bits on the FD at the moment, so plenty of learning to be done.



Single turbo headers are a lot easier to insert the probe than the OE twin pack.



Dan

 

well once you look at the diagram and drive around with a/f monitor you can see it going into each section



mike

 

Oh with the stock computer right? So it sees 14.7 on light load cruising right?



C

 

yep, thats right. its in closed loop 14.7 +/- whatever the 02 corrects to. we had ours cruising at 15.5:1ish



they have it running at 14.7:1 because thats where the cat is most happy (i think), its bad for the cat to go leaner than 14.7:1, or have misfires. thats one of the reasons they are so rich stock is to keep the cat from running too hot. the cat is not affected by rich mixture, it catylises oxygen, the more oxygen the hotter it gets



mike

 

how is this wide band with the lsu-4 sensor



http://www.motec.com/products/plm/plm.htm



is it any better than the previous mentioned ones?



just wondering because I read this form the merced import site



"News Flash: The LM-1 w/ the Bosch O2 Sensor won't work with turbocharged Rotary engine. You have to use the NTK O2 Sensor. That is unless you have a 1" bypass tube welded in line for the sensor."

 

But those reading are also affected by the air pump, adding more oxygen dont u think?



I guess is ok to run the car for cruising around 14.7. I ran 14.0 coming to CA, didn't sound like it was hesitating.

 

we're running like 15.5-14.5 going down to la, cruising.



mike

 

Can anyone explain about how a/f tuning and timing tuning work in conjuction with the spooling of the turbo?I was reading a/f and timing is directly related to how the turbos going to spool.I imagine this is another variabale ontop of egt temps and a/f ratios one needs to consider when tuning.



Thanks

 

not nesecarily true from my understanding.

i did not know how to put it to words before, but recently Matt (hitman) had a good explination of this on the haltech mailing list. it went something like this...

the same amount of fuel being combusted to make up a certain a/f ratio will have a diferent egt reading due to timing. if you have the timing advanced the heat is going to be held in the motor heating it (internals of motor) up. if timing is to far retarted, the internals will run cooler, but the heat will be seen in the exhaust (higher egt's) you need to find the happy medium for your motor.

did my explaination of HIS explination make any sence? LOL [/quote]

My original post, which was obviously edited, mentions the importance of timing.