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A/F ratio tuning
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Fasteddie313  



Joined: 29 Sep 2013
Posts: 2224
Location: MI

PostPosted: Mon Mar 08, 2021 1:14 am    Post subject: Reply with quote

You need to pay attention to the duty cycle of the frequency valve to set idle AFR, or unplug your oxygen sensor..
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MikeDanger  



Joined: 21 Nov 2002
Posts: 636
Location: Denver

PostPosted: Mon Mar 08, 2021 6:32 pm    Post subject: Reply with quote

Fasteddie313 wrote:
You need to pay attention to the duty cycle of the frequency valve to set idle AFR, or unplug your oxygen sensor..


Well its not idle thats the issue, its when Its at part throttle. Next time maybe Ill try the O2 disconected.
Seems No matter what change I make it seems to Not change the mid range very much, its always fluctuating between 14-15. But goes to 12 on full throttle. Im able to change the idle AFR and WOT AFR, but even though I kept enriching the CIS and the WUR, some times it even got LEANER on mid throttle (but would still go rich on WOT) How is that possible?

What am I missing?? I thought maybe a leak, but most hoses have been changed, and I checked for leaks at idle both with a Propane gas, and Starting fluid (intake/head/injectors)

On the other hand maybe I dont have the Vac line hooked to the right spot? (connected to the port on the throttle) maybe Vac line is leaning it out?


Can anyone tell me what the Running warm Control pressure should be?
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MikeDanger  



Joined: 21 Nov 2002
Posts: 636
Location: Denver

PostPosted: Mon Mar 08, 2021 6:39 pm    Post subject: Reply with quote

Carrera RSR wrote:
MikeDanger wrote:
Its a little tough to tune, when you have to jump out, open the hood, get back in..... and repeat several times.

Any suggestions from this point?


Put it on a dynometer with a tuner who knows his onions and can adjust with clear view of performance gains/losses with each adjustment. Can also keep an eye on AFR and adjust at the same time with load on the engine. Yes it costs money, but will have a quicker outcome and limit the change of grenading the motor


That would be a good Idea, but at the moment I have almost zero money to spare, and any I can spare is for finishing the intercooler install.

But also Im eventually planning to install EFI, I just want to get this safely driveable, not perfect. (and then maybe get the dyno for the EFI tuning)

All i really need to do is figure out how to richen the part-throttle A/F even On a dyno that would be a pain.

at this point im going to swap out the other 2 WUR's I have and see what difference it makes, to rule the WUR in or out
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Carrera RSR  



Joined: 08 Jan 2010
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Location: Somerset, UK

PostPosted: Mon Mar 08, 2021 9:18 pm    Post subject: Reply with quote

The fuel is inherently difficult to tune on CiS. Every positive action has a negative one somewhere else. Hence my comment regarding others using specially adapted adjustable WUR's. There is also a programmable WUR out there. You're pissing in the wind without some specialist knowledge and dyno time. Or switching to EFi sooner than later. With CiS, its full of compromises. Optimised AFR at every rpm, ignition advance and boost pressure is the unfound holy grail which is what drives people to EFi on modified turbos
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Fasteddie313  



Joined: 29 Sep 2013
Posts: 2224
Location: MI

PostPosted: Mon Mar 08, 2021 10:44 pm    Post subject: Reply with quote

MikeDanger wrote:
Fasteddie313 wrote:
You need to pay attention to the duty cycle of the frequency valve to set idle AFR, or unplug your oxygen sensor..


Well its not idle thats the issue, its when Its at part throttle. Next time maybe Ill try the O2 disconected.
Seems No matter what change I make it seems to Not change the mid range very much, its always fluctuating between 14-15. But goes to 12 on full throttle. Im able to change the idle AFR and WOT AFR, but even though I kept enriching the CIS and the WUR, some times it even got LEANER on mid throttle (but would still go rich on WOT) How is that possible?

What am I missing?? I thought maybe a leak, but most hoses have been changed, and I checked for leaks at idle both with a Propane gas, and Starting fluid (intake/head/injectors)

On the other hand maybe I dont have the Vac line hooked to the right spot? (connected to the port on the throttle) maybe Vac line is leaning it out?


Can anyone tell me what the Running warm Control pressure should be?


What your missing is that the lambda system will keep you fluctuating 14-15 at idle and midrange..
Lambda also has a WOT switch to enrichen at full throttle..

BTW.. 14-15 in midrange is very good..
WOT should be 11.0-11.5
I’d say 12 is a bit too lean on WOT with no intercooler..
Even with a good intercooler I’d try to keep it just under 12 in boost..
What afr are you aiming for?
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MikeDanger  



Joined: 21 Nov 2002
Posts: 636
Location: Denver

PostPosted: Tue Mar 09, 2021 7:53 am    Post subject: Reply with quote

are there any videos of someone driving with both the AF and boost gauge in the view? so i can compare??

thats another thing, hard to drive around while staring at the gauges!



I can enrich the WOT/FullBoost with the "brass plug" port I thought 12 was pretty good

I just want to make sure I don't burn up the motor/blow HG.

It actually pulls surprisingly well for only 7Psi


is there any way to adjust the labmda?
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MikeDanger  



Joined: 21 Nov 2002
Posts: 636
Location: Denver

PostPosted: Tue Mar 09, 2021 8:00 am    Post subject: Reply with quote

Carrera RSR wrote:
The fuel is inherently difficult to tune on CiS. Every positive action has a negative one somewhere else. Hence my comment regarding others using specially adapted adjustable WUR's. There is also a programmable WUR out there. You're pissing in the wind without some specialist knowledge and dyno time. Or switching to EFi sooner than later. With CiS, its full of compromises. Optimised AFR at every rpm, ignition advance and boost pressure is the unfound holy grail which is what drives people to EFi on modified turbos


I wasn't planning on putting this much effort into the CIS, I just don't know when Ill get to the EFI install, I have to build the wiring harness and acquire a few other bits and peices.

(and my daily driver died (bmw 540i touring) so I also need to save money to get another wagon ;-(

The weird thing I noticed now after, messing with the WUR so much. The A/F at mid throttle is now flickering, where as it didnt at the start of this thread. Not sure what to make of it.

I wonder if there are any hidden spots for vacuum leaks I make have missed?

Remember initially I was getting 9! mid throttle initially.

The saga continues! (come on Nasdaq!!!!)
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Fasteddie313  



Joined: 29 Sep 2013
Posts: 2224
Location: MI

PostPosted: Tue Mar 09, 2021 8:22 am    Post subject: Reply with quote

MikeDanger wrote:
are there any videos of someone driving with both the AF and boost gauge in the view? so i can compare??

thats another thing, hard to drive around while staring at the gauges!



I can enrich the WOT/FullBoost with the "brass plug" port I thought 12 was pretty good

I just want to make sure I don't burn up the motor/blow HG.

It actually pulls surprisingly well for only 7Psi


is there any way to adjust the labmda?


https://m.youtube.com/watch?v=POVuP3VRAlg

https://m.youtube.com/watch?v=UoVKeAE8rRA

Heh
Wouldn’t try that without an IC
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MikeDanger  



Joined: 21 Nov 2002
Posts: 636
Location: Denver

PostPosted: Tue Mar 09, 2021 8:36 am    Post subject: Reply with quote

Ok I just found a leak at the #3 injector, I sprayed Starting fluid and carb cleaner at the injector and the engine bogged. could that be enough to throw the A/F off that much?
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MikeDanger  



Joined: 21 Nov 2002
Posts: 636
Location: Denver

PostPosted: Tue Mar 09, 2021 2:11 pm    Post subject: Reply with quote

Fasteddie313 wrote:
MikeDanger wrote:
are there any videos of someone driving with both the AF and boost gauge in the view? so i can compare??

thats another thing, hard to drive around while staring at the gauges!



I can enrich the WOT/FullBoost with the "brass plug" port I thought 12 was pretty good

I just want to make sure I don't burn up the motor/blow HG.

It actually pulls surprisingly well for only 7Psi


is there any way to adjust the labmda?


https://m.youtube.com/watch?v=POVuP3VRAlg

https://m.youtube.com/watch?v=UoVKeAE8rRA

Heh
Wouldn’t try that without an IC


Unfortunately those dont show a steady Mid throttle.
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MikeDanger  



Joined: 21 Nov 2002
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PostPosted: Tue Mar 09, 2021 3:23 pm    Post subject: Reply with quote

Pulled the 3rd injector found this:


Also is there supposed ot be an O-ring between the injector spacer and the head?
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MikeDanger  



Joined: 21 Nov 2002
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PostPosted: Tue Mar 09, 2021 4:08 pm    Post subject: Reply with quote

Is there a way to disconnect the o2 up top? not in the mood to jack up the car and climb under.
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MikeDanger  



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PostPosted: Tue Mar 09, 2021 4:54 pm    Post subject: Reply with quote

well heres another fly in the ointment.
I just figured out the WUR im using it out of an s1 (mine is an s2) I had 3 WUR's I guess the one i grabbed to make adjustable just happened to be the S1, how much could that be playing a factor?
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Carrera RSR  



Joined: 08 Jan 2010
Posts: 2194
Location: Somerset, UK

PostPosted: Tue Mar 09, 2021 6:37 pm    Post subject: Reply with quote

MikeDanger wrote:
well heres another fly in the ointment.
I just figured out the WUR im using it out of an s1 (mine is an s2) I had 3 WUR's I guess the one i grabbed to make adjustable just happened to be the S1, how much could that be playing a factor?


Doesn't matter....theres no real difference
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1980 931 - forged pistons, Piper cam, K27/26 3257 6.10 hybrid turbo, 951 FMIC, custom intake, Mittelmotor dizzy & cam pulley, H&S exhaust, GAZ Gold, Fuch'ed, Quaife
Now www.924board.org/viewtopic.php?t=34690
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Carrera RSR  



Joined: 08 Jan 2010
Posts: 2194
Location: Somerset, UK

PostPosted: Tue Mar 09, 2021 6:38 pm    Post subject: Reply with quote

MikeDanger wrote:
Pulled the 3rd injector found this:


Also is there supposed ot be an O-ring between the injector spacer and the head?


Vacuum leaks will not be tolerated with CiS. Screws everything.
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1980 931 - forged pistons, Piper cam, K27/26 3257 6.10 hybrid turbo, 951 FMIC, custom intake, Mittelmotor dizzy & cam pulley, H&S exhaust, GAZ Gold, Fuch'ed, Quaife
Now www.924board.org/viewtopic.php?t=34690
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