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

Fuel control via WUR + rpm boost switch
Goto page 1, 2, 3, 4, 5  Next
 
Post new topic   Reply to topic    924Board.org Forum Index -> 931 Tech.
View previous topic :: View next topic  
Author Message
Carrera RSR  



Joined: 08 Jan 2010
Posts: 1970
Location: Somerset, UK

PostPosted: Sat Jul 02, 2016 7:39 am    Post subject: Fuel control via WUR + rpm boost switch Reply with quote

Looking for some advice in tuning the fuel delivery. Running way too rich at WOT with AFR's in the high 9's and low 10's. Cruise and idle is in the 14's, usually bang on 14.7. Mid throttle and mid boost of 0.6-0.7 bar sees mid 12 AFR. So looking to lean off WOT without affecting the other results. Suggestions please as Google searching this forum has come up blank so far. Thanks
_________________
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
Then www.924board.org/viewtopic.php?t=31252


Last edited by Carrera RSR on Mon Jul 18, 2016 5:52 pm; edited 1 time in total
Back to top
View user's profile Send private message
Rasta Monsta  



Joined: 12 Jul 2006
Posts: 11378
Location: PacNW

PostPosted: Sat Jul 02, 2016 9:31 am    Post subject: Reply with quote

Adjustable WUR?
_________________
Toofah King Bad

  • Red (1987 924S) - Pro44/Spec944
Back to top
View user's profile Send private message Visit poster's website
morghen  



Joined: 21 Jan 2005
Posts: 8163
Location: Romania

PostPosted: Sat Jul 02, 2016 3:52 pm    Post subject: Reply with quote

I have the same issue. WUR's natural responce is that it enriches too much on higher boost. All that fuel will actually cause detonation. This is the limit of the CIS. If UTCIS would have worked as intended we would all have very good control over the mixture..but it just does not.
In a month or so I will test out a modified S1 WUR with adjustability added. The way i see it, that screw will limit the amount of fuel the WUR will provide.
If it does that, i might just keep CIS for a longer period of time.
_________________
Ruby-sh 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: 1970
Location: Somerset, UK

PostPosted: Sat Jul 02, 2016 5:31 pm    Post subject: Reply with quote

Rasta Monsta wrote:
Adjustable WUR?


And.....
_________________
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
Then www.924board.org/viewtopic.php?t=31252
Back to top
View user's profile Send private message
Carrera RSR  



Joined: 08 Jan 2010
Posts: 1970
Location: Somerset, UK

PostPosted: Sat Jul 02, 2016 5:41 pm    Post subject: Reply with quote

morghen wrote:
I have the same issue. WUR's natural responce is that it enriches too much on higher boost. All that fuel will actually cause detonation. This is the limit of the CIS. If UTCIS would have worked as intended we would all have very good control over the mixture..but it just does not.
In a month or so I will test out a modified S1 WUR with adjustability added. The way i see it, that screw will limit the amount of fuel the WUR will provide.
If it does that, i might just keep CIS for a longer period of time.


Whilst a rich mixture is said to cool combustion and avoid det, it can also increase the risk as well. Too much fuel can also increase EGT's. So I'd like to get AFR close to 12 on WOT. I have a Bosch manual. It explains all the CIS parts but not how to control fuel. FSM's and forum threads discuss fuel pressures to factory settings. I cannot find any discussions on pros / cons for turbos in getting fuel control on modified turbos across the throttle and boost range . So I'd like some further learning before I go down this road.
_________________
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
Then www.924board.org/viewtopic.php?t=31252
Back to top
View user's profile Send private message
CÚdric  



Joined: 27 Aug 2004
Posts: 1973
Location: Sweden

PostPosted: Sat Jul 02, 2016 7:00 pm    Post subject: Reply with quote

Bleed valve on the boost line to the wur

http://forums.pelicanparts.com/porsche-911-technical-forum/218814-made-adjustable-wur-step-step-got-pics.html

I suppose an adjustable wur like In the link above just offsets the curve.
_________________
┤80 924 Turbo
Back to top
View user's profile Send private message MSN Messenger
Carrera RSR  



Joined: 08 Jan 2010
Posts: 1970
Location: Somerset, UK

PostPosted: Sat Jul 02, 2016 8:37 pm    Post subject: Reply with quote

Thanks Cedric. This is the reason for my post. Adjusting control pressures via the WUR appears to move the curve up an down the Rev/boost range. Leaner at the top means very lean at the bottom end. So just sounding out the theory and experiences here
_________________
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
Then www.924board.org/viewtopic.php?t=31252
Back to top
View user's profile Send private message
morghen  



Joined: 21 Jan 2005
Posts: 8163
Location: Romania

PostPosted: Sat Jul 02, 2016 9:50 pm    Post subject: Reply with quote

This looks different.


http://www.928motorsports.com/parts/cisreg.php

I'm wondering if there is a way to limit the travel it does to upp the control pressure.
_________________
Ruby-sh 924
Back to top
View user's profile Send private message Visit poster's website Yahoo Messenger MSN Messenger
morghen  



Joined: 21 Jan 2005
Posts: 8163
Location: Romania

PostPosted: Sat Jul 02, 2016 10:10 pm    Post subject: Reply with quote

Anyway, now thinking about another way to control this.
The thing you have to do is lift up the bimetal so more fuel goes to the tank instead of staying there to make the air plate lift higher.

So...boost pushes the bimetal down...(if no boost is applied no enrichment).
How about an inline boost controller to limit the boost that the WUR gets?

Say you're runin 1bar at the manifold and 1bar at the WUR means 10AFR.
Well lets try to reduce 1bar at the WUR to 0.8bar.
So we need a pressure restrictor inline between the manifold and the WUR.


EDIT -Here is what i'm thinking:
idea by m0rghen, on Flickr
_________________
Ruby-sh 924


Last edited by morghen on Sat Jul 02, 2016 11:13 pm; edited 1 time in total
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: 1970
Location: Somerset, UK

PostPosted: Sat Jul 02, 2016 10:55 pm    Post subject: Reply with quote

morghen wrote:
This looks different.


http://www.928motorsports.com/parts/cisreg.php

I'm wondering if there is a way to limit the travel it does to upp the control pressure.


Makes a WUR which isn't boost controlled to one that is. We have this in our WUR's already and leaning out too far. Would work in conjunction with the AFR guage

Every thread I am reading is trying to richen the mixture at 1.0bar plus, not lean it off. I've run my car upto 1.3bar and still get 9.8-10 AFR. I also get det easier without octane boosting.

Quite like the idea of bleeding off boost to the WUR to limit the boost enrichment. I only sold a turbosmart boost controller last year damn it. Could rig up another boost gauge to ensure I avoid cutting off boost completely.

Some days I wish I did go EFi.
_________________
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
Then www.924board.org/viewtopic.php?t=31252
Back to top
View user's profile Send private message
morghen  



Joined: 21 Jan 2005
Posts: 8163
Location: Romania

PostPosted: Sat Jul 02, 2016 11:27 pm    Post subject: Reply with quote

Or a simpler one i think: a small flow restrictor that bleeds out the boost before the wur.
Ofcourse bleeding boost = enriching but since the WUR responce isnt linear this should still be effective.

idea2 by m0rghen, on Flickr
_________________
Ruby-sh 924
Back to top
View user's profile Send private message Visit poster's website Yahoo Messenger MSN Messenger
morghen  



Joined: 21 Jan 2005
Posts: 8163
Location: Romania

PostPosted: Sun Jul 03, 2016 5:51 am    Post subject: Reply with quote

more refining

idea3 by m0rghen, on Flickr
_________________
Ruby-sh 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: 1970
Location: Somerset, UK

PostPosted: Sun Jul 03, 2016 7:32 am    Post subject: Reply with quote

Is the solution throwing Brian Leask $600 for a modified adjustable WUR and rpm enrichment device?

If so I'll be looking for a stateside buddy to sell me and post a WUR direct to mr Leask on my behalf in the near future.
_________________
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
Then www.924board.org/viewtopic.php?t=31252
Back to top
View user's profile Send private message
Dutch924-racer  



Joined: 23 Jul 2007
Posts: 1059
Location: The Netherlands

PostPosted: Sun Jul 03, 2016 3:16 pm    Post subject: Reply with quote

you might contact Mittelmotor, I asume they run above 0.9 bar with their GTS replica.

Or convert to KE jetronic:


_________________
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: 1970
Location: Somerset, UK

PostPosted: Sun Jul 03, 2016 6:15 pm    Post subject: Reply with quote

I have already contacted Mittemotor for their suggestions. Awaiting a response.

I'd bypass the KE and go full EFi if I wanted the to go through the pain of converting to anything. The romantic in me wants to keep CIS and the original look. The head wants more control, cleaner burn and more reliable hp.
_________________
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
Then www.924board.org/viewtopic.php?t=31252
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 + 10 Hours
Goto page 1, 2, 3, 4, 5  Next
Page 1 of 5

 
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