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kenikh kenikh is offline
3 restos WIP = psycho
kenikh's Avatar
Join Date: Feb 2005
Location: North of Exit 17
Posts: 7,729
OK everyone, finally time for a real update.

Got the new turbo installed without drama this AM. It's a 965 vintage K27-7200 with a big billet compressor wheel on a #11 hot housing. First some impressions, then a question for those in the know on CIS tuning.

IMPRESSIONS: the turbo is more responsive and linear than the old 7006. Spools about 500 RPM sooner, as well. For better or worse, the turbo "hit" is much less dramatic. The 7006 sent my mind into an altered state. This is much more predictable, but is less exciting and less likely to induce psychotropic hallucinations from excessive acceleration. Not sure how I feel about that...

MY QUESTION has to do with AFRs. This sucker is definitely blowing more air and much earlier. My AFRs from 2000 RPM until fuel dump at 4500 are lean, as in 13.5:1 lean. That's a full point higher than the old turbo.

As a reminder, I have a Leask WUR and delay solenoid set to 4500 RPM.

Once the fuel dump hits, the pendulum swings the other way: I'm pegged at 10:1 AFR from 4500, all the way to redline. The car as a result feels sluggish at fuel dump, where it should feel like it is taking off like a rocket ship.

So, my best guess is that I need to lean out the warm control pressure, fatten the idle mixture a few clicks to get it back up to 12.5 and perhaps move the dump RPM up a couple hundred RPM.


Obligatory pics below.

Sent from my Nexus 6P using Tapatalk

- 1965 911
- 1969 911S
- 1980 911SC Targa
- 1979 930

Last edited by kenikh; 10-09-2017 at 02:49 PM..
Old 10-09-2017, 12:41 PM
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