Show full size 924Board.org
Discussion Forum of 924.org
 
 FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   RegisterRegister 
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 
 Technical FAQ924 FAQ (Technical)   Technical924 Technical Section   Jump to 924.org924.org   Jump to PCA 924 Registry924 Registry

What are the AFR ratio's you want for a 931 ?
Goto page Previous  1, 2
 
Post new topic   Reply to topic    924Board.org Forum Index -> 931 Tech.
View previous topic :: View next topic  
Author Message
morghen  



Joined: 21 Jan 2005
Posts: 7832
Location: Romania

PostPosted: Sat May 06, 2017 7:05 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.
_________________
red 924 and not red 924
Back to top
View user's profile Send private message Visit poster's website Yahoo Messenger MSN Messenger
Carrera RSR  



Joined: 08 Jan 2010
Posts: 1551
Location: Somerset, UK

PostPosted: Sat May 06, 2017 6:27 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
_________________
1980 931 - forged pistons, Piper cam, CGT turbo, 951 ducted FMIC, custom intake, Mittelmotor dizzy & cam pulley, H&S exhaust, GAZ Gold, Fuch'ed, Quaife LSD
Now www.924board.org/viewtopic.php?t=34690
Then www.924board.org/viewtopic.php?t=31252
Back to top
View user's profile Send private message
morghen  



Joined: 21 Jan 2005
Posts: 7832
Location: Romania

PostPosted: Sat May 06, 2017 11:13 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.
_________________
red 924 and not red 924
Back to top
View user's profile Send private message Visit poster's website Yahoo Messenger MSN Messenger
Dutch924-racer  



Joined: 23 Jul 2007
Posts: 1004
Location: The Netherlands

PostPosted: Sun May 07, 2017 6:07 am    Post subject: Reply with quote

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

Cruise stays about 17. Is that a problem ?
_________________
937 trackday car
Series 2 engine
951S turbo and intercooler
937 DITC
Fast road camshaft
Forge recirculation valve + boost controller
Back to top
View user's profile Send private message
Carrera RSR  



Joined: 08 Jan 2010
Posts: 1551
Location: Somerset, UK

PostPosted: Sun May 07, 2017 6:57 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
_________________
1980 931 - forged pistons, Piper cam, CGT turbo, 951 ducted FMIC, custom intake, Mittelmotor dizzy & cam pulley, H&S exhaust, GAZ Gold, Fuch'ed, Quaife LSD
Now www.924board.org/viewtopic.php?t=34690
Then www.924board.org/viewtopic.php?t=31252


Last edited by Carrera RSR on Mon May 08, 2017 8:35 pm; edited 2 times in total
Back to top
View user's profile Send private message
ideola  



Joined: 01 Oct 2004
Posts: 15499
Location: Woodstock IL

PostPosted: Mon May 08, 2017 9:57 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.
_________________
15 981 GTS | 88 924S SE | 82 931 Holbert | 82 931 Rallye | 81 937 | 81 Euro 931 | 81 Weissach | 80 US 928 | 80 US 931 '941' | 80 US 931 | 80 931 GTR | 79 Sebring | 78 D-Prod Replica | 78 w/D-Prod kit | 78 Poli-Form | 78 Limited Edition | 77 Martini
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic    924Board.org Forum Index -> 931 Tech. All times are GMT + 11 Hours
Goto page Previous  1, 2
Page 2 of 2

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum


Powered by phpBB © 2001, 2005 phpBB Group