Thoughts on my AFR plz

[zeb930]

Motor is newly rebuilt stock 3.3 with K27 7200, fullbay IC, freeflow exhaust, HKS boost controller. One mode for street 1.0 bar and one for track 0.8 bar.

For 1.0 bar mode I see the following AFRs (Autronic wideband air/fuel meter)

idle 14.5
cruise around 15
WOT at boost onset dippes to 10.9-11.0
Slowly rises to 12.1-12.2 at 6000rpm
At 6800 12.6 (a bit high I know but fairly ok for CIS yes???)

With 0.8 mode I see 10.7 at WOT and 12.2 at 6800rpm (the mode I will use on trackdays)

Am I safe here? Always best octane gas, and fullbay IC..

Thanks/ zeb

[A930Rocket]

Like pretty good. I'd use 100 octane at the track. Expensive but cheaper than a rebuild.

Are you EFI or CIS?

[gogomobil]

very good numbers, to be on the safe side and if your car is CIS make sure that the spray pattern of all 6 injectors is within spec. I need to do this on my car too because I want to make sure all cylinders get the same amount of fuel.

[zeb930]

CIS and i run shell v-power 99 octane. (I think you have some other octane meteringsystem in US though) but the v-power is the best standard fuel you can get over here. Thanks!

[zeb930]

Originally Posted by gogomobil

very good numbers, to be on the safe side and if your car is CIS make sure that the spray pattern of all 6 injectors is within spec. I need to do this on my car too because I want to make sure all cylinders get the same amount of fuel.

Thanks! Good idea about the injectors.. I THINK I am safe because I checked the AFRs (before I mounted the HKS boostcontroller) at standard boost and they where a bit higher WOT 11.4 and 12.9-13.0 at 6800. And I have run this for 3 whole summers including a couple of track days.

Then I mounted the HKS BC and fiddled with the CO screw until I got the numbers I posted in my first post. HOPE im safe..

[mark houghton]

Originally Posted by zeb930

Thanks! Good idea about the injectors.. I THINK I am safe because I checked the AFRs (before I mounted the HKS boostcontroller) at standard boost and they where a bit higher WOT 11.4 and 12.9-13.0 at 6800. And I have run this for 3 whole summers including a couple of track days.

Then I mounted the HKS BC and fiddled with the CO screw until I got the numbers I posted in my first post. HOPE im safe..

There's a very good post and a lot of discussion on the topic of balancing injector flow. It's a good DIY project, and one that I intend to do maybe this winter...just for peace of mind. Do a search and you should be able to find it.

The fear of having a bad injector is that the affected cyclinder could be running in the danger zone on boost and you would never know it if just looking at the AFR's coming out of the exhaust...which is just a composite average of all 6 cylinders. I becomes even more critical if boosting beyond .8bar.

[zeb930]

Originally Posted by mark houghton

There's a very good post and a lot of discussion on the topic of balancing injector flow. It's a good DIY project, and one that I intend to do maybe this winter...just for peace of mind. Do a search and you should be able to find it.

The fear of having a bad injector is that the affected cyclinder could be running in the danger zone on boost and you would never know it if just looking at the AFR's coming out of the exhaust...which is just a composite average of all 6 cylinders. I becomes even more critical if boosting beyond .8bar.

Thanks! Ill look it up..

[zeb930]

Just went for a ride.. Cant believe how much better the midrange gets with the boostcontroller.. amazing!!

0,5 bar at 2900rpm and full 1,0 bar at 3150rpm..

Having the BC connected to both top and bottom line on the wastegate really makes wonders for the midrange.