Tuning with wide band a/f ratio

[kicknurass4fun]

Hi
To start this off I have searched quite a bit to make sure there wasn't already a thread on this. If there is and i couldn't find it i am sorry. I am just curious as to what you guys with wide band o2s are tunning a/f ratio to. I am running 19psi with a garret to4be v-trim turbo. I have a smaller front mount but it gets the job done. What kind of a/f ratios would you guys recommend me tunning for? Thanks

 

[project_tsi]

Most modified DSM's like to run at a 11.7-11.9 A/F ratio at WOT at the top of 3rd.

 

[kicknurass4fun]

Thanks thats about what I thought. I have been tuning for 11.5 to be on the safe side. Would I notice a difference if I lean out the a/f? Maybe I will lean it out a little bit to 11.8. I will watch my knock and make sure there isnt any!!! If there is any knock can I turn the timing down a little bit with the cam angular sensor? Or should I not do that. Thanks

 

[99gst_racer]

Thanks thats about what I thought. I have been tuning for 11.5 to be on the safe side. Would I notice a difference if I lean out the a/f? Maybe I will lean it out a little bit to 11.8. I will watch my knock and make sure there isnt any!!! If there is any knock can I turn the timing down a little bit with the cam angular sensor? Or should I not do that. Thanks

Yeah, just take out fuel until you knock. 11.5 is safe, but if you can get to 11.8 without knocking, go for it. I doubt you'd be able to get much leaner than 11.8 on pump without knocking though.....

 

[cbellsondsm]

Yeah, just take out fuel until you knock. 11.5 is safe, but if you can get to 11.8 without knocking, go for it. I doubt you'd be able to get much leaner than 11.8 on pump without knocking though.....

But if it does start knock could adjust the base timing with the cam angular sensor to get rid of the knock? Thanks

 

[project_tsi]

But if it does start knock could adjust the base timing with the cam angular sensor to get rid of the knock? Thanks

No, the CAS is for adjusting base timing. You need a program, like Link, or equivenent to adjust timing at certain RPM's under boost.

 

[94Jettameowpsst]

Doesnt your cas directly correspond to your timing at wot as well though? I was knockin hard core and when i adjusted my cas accordingly, i had signifigantly less knock.

Secondly, if you did lean it out to say 11.8 from 11.5 wouldnt it theoretically make it richer since you retarded the timing anyways? (less hot spark) Idk im just asking?

 

[project_tsi]

It will only help at WOT if your way the hell off of base timing.

 

[kicknurass4fun]

Well think about it. If the car goes off of base timing with the CAS it wiill also go off of WOT with it to. So if you want your timing to be a degree or so lower/higher all over the rpm range at WOT and you adjust the CAS a degree or so lower/higher using a timing light. Then the timing will be a that much lower/higher at WOT. The only problem I see with that is the car also uses the CAS for the injector timing. So you are not only messing with the timing but also when the time at witch the injectors open. This is just what i kind of put together when i thought about how the whole system works(no one told me this). Which is why i posted a topic on tunning. So if any of this is wrong please let me know. Thanks

 

[project_tsi]

You are wrong. I just tried explaining it to you.

 

[kicknurass4fun]

No, the CAS is for adjusting base timing. You need a program, like Link, or equivenent to adjust timing at certain RPM's under boost.

You explained it to me as if i want to go in and change it at certain rpm points. I am simply saying that if you change your base timing from 8* to 6* with the CAS then your timing will be 2* lower through the whole rpm range at WOT. The ecu just bases its timing off of where the CAS is set expecting it to be set at the proper base timing.

 

[Drift_SM]

do our dsm's have both wide bands and short bands?......i know some cars do. Is it better to use your a/f gauge on wide band or short?

sory its off topic...

 

[project_tsi]

You explained it to me as if i want to go in and change it at certain rpm points. I am simply saying that if you change your base timing from 8* to 6* with the CAS then your timing will be 2* lower through the whole rpm range at WOT. The ecu just bases its timing off of where the CAS is set expecting it to be set at the proper base timing.

No, other than base timing, your timing is pulled or added based on a few factors, octane level, knock, amount of boost, and your A/F ratio.
Just because your base timing is 7* BTDC, and your timing at the top of third is 17*, changing your base timing to 10* will not yeild you 20* at the top of third, it doesn't work that way.

 

[project_tsi]

do our dsm's have both wide bands and short bands?......i know some cars do. Is it better to use your a/f gauge on wide band or short?

sory its off topic...

The correct lingo is wideband and narrowband. And no, DSM's do not come w/ any type of wideband. Our cars only come w/ narrowbands. 1G DSM's have 1 02 sensor to run off of, but 2G DSM's have 2 02 sensor, one pre cat, one post cat.

 

[kicknurass4fun]

It wont read out on a palm like that but technically it will be sparking at that degree. Assuming there is no knock and every thing is tuned properly. I talked to SBR about it. The car will base the timing off of the maps inside of the ecu but changing the CAS will change the over all timing through everything. If i have any knock and i turn the CAS even the littlest bit counter clock wise it will make sum of the knock go away. There for it must be retarding the timing. I'm not saying i am 100% correct. I just am pretty sure that adjusting the CAS will change the timing at which the car bases all timing off of. Any one else know. Thanks

 

[Raph]

i tuned for 12 on a Autobahn run last monday.. but then i tuned back for 11.4 to be safe..

yes,there was a slight difference in response with the 12 AFR..(i had shell v power 100 octane in the tank,so it was fine)


running 11.4 AFRs now

Tuning is fun!

 

[cagri]

Yes CAS change will apply at all times, if you set your timing to 8 degrees base, and at max airflow at 7000 rpm ecu is programmed to run at 16 timing then it will run at 19 timing if there are no knock events. Your logger will still show 16 timing since ecu has no idea that you set the base timing to 8 and it assumes base timing of 5 degrees.

 

[kicknurass4fun]

Yes CAS change will apply at all times, if you set your timing to 8 degrees base, and at max airflow at 7000 rpm ecu is programmed to run at 16 timing then it will run at 19 timing if there are no knock events. Your logger will still show 16 timing since ecu has no idea that you set the base timing to 8 and it assumes base timing of 5 degrees.

Thanks, thats exactly what i thought and was told from a respectable shop. Its Funny how some way I lost points on this one.

 

[wkd4g63]

i run mine at..... 11:1 to 11:3 a/f ...... id rather be safe than sorry. Also depends on what kind af gas you have access to , all we have is 91 pump..... just add some c-16!

-JP

 

[Staytuned]

Don't set yourself a desired A/F ratio and think that is where you have to be to make the most power. Power comes from boost and timing control. Lean yourself out till you see some knock then add a little fuel. You might be at 10.5:1 or like me at 11.7:1 thats not as important as timing and air flow (boost). Do not lower timing so you can run leaner. People have seen very little gain from a leaning out, even at 2 whole A/F points.

 

[gSx_r1der]

I have been advised to run 10.7-8 on my stock 7-bolt, with a 16g at 20psi. I have a zeitronix wideband doing the dirty with the tuning. I dont think that this would be too dangerous, although I am running rc 1000s so maybe thats why....

 

[wallyman]

From my experiances i would say run around 11.2. Then i would advance timing until knock then take a little timing away.

 

[kicknurass4fun]

Thanks for the help guys!!! I will definitely keep that in mind when tunning. I aways thought you don't want to run your car any richer then 11.5 but i guess i was wrong. I set my base timing to 5 degrees and i am running 20lbs of boost with water injection and a good front mount so i shouldn't see to much knock. I haven't tuned the car since those mods but i am getting ready to and when I do I will aim more for running a little bit on the rich side (11.2 when needed) rather then turning the boost down. Thanks again!!!