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What are the AFR ratio's you want for a 931 ?
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morghen  



Joined: 21 Jan 2005
Posts: 8868
Location: Romania

PostPosted: Sat May 06, 2017 6:05 am    Post subject: Reply with quote

I can confirm that the AF allen screw does change the overall mixture, not just the idle mixture.
The plugs on my 931 were grey/white...that's lean and the idle was lumpy.
I adjusted for more fuel and the plugs are brown + black...idle is steady and pedal response is improved.

I have to get a wideband kit for this car as well soon.
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Carrera RSR  



Joined: 08 Jan 2010
Posts: 2309
Location: Somerset, UK

PostPosted: Sat May 06, 2017 5:27 pm    Post subject: Reply with quote

But it will be linear through the whole range. Rich idle means super rich at WOT. The WUR is the place to change idle mixture from top end. Boost enrichment device is where you can manage mid range when coming on boost.

Or go EFi
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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
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morghen  



Joined: 21 Jan 2005
Posts: 8868
Location: Romania

PostPosted: Sat May 06, 2017 10:13 pm    Post subject: Reply with quote

Yeap, that's right.
I'm going to install EFI on my red 924...not sure weather this year or the next...but I do plan to in the near future.
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Dutch924-racer  



Joined: 23 Jul 2007
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Location: The Netherlands

PostPosted: Sun May 07, 2017 5:07 am    Post subject: Reply with quote

Idle is now about 14, on boost also arounnd 14.

Cruise stays about 17. Is that a problem ?
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Carrera RSR  



Joined: 08 Jan 2010
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Location: Somerset, UK

PostPosted: Sun May 07, 2017 5:57 am    Post subject: Reply with quote

Idle and cruise should be 14.7 or slightly richer. Wot on full boost should be 12 or richer. Most stock 931s will be circa 10 to avoid det
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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
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Then www.924board.org/viewtopic.php?t=31252


Last edited by Carrera RSR on Mon May 08, 2017 7:35 pm; edited 2 times in total
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ideola  



Joined: 01 Oct 2004
Posts: 15548
Location: Spring Lake MI

PostPosted: Mon May 08, 2017 8:57 am    Post subject: Reply with quote

Dutch924-racer wrote:
Idle is now about 14, on boost also arounnd 14.

Cruise stays about 17. Is that a problem ?


Something is definitely amiss. I would start by looking for air/boost/vac leaks in the intake tract. You should be getting a steady 17Hg of vacuum on fully-warmed-up idle. If it's less, you have a leak somewhere and need to find it.
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