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MikeDanger
Joined: 21 Nov 2002
Posts: 774
Location: Denver
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 Posted: Sat Aug 28, 2021 11:57 am Post subject: CIS boost enrichment |
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I was thinking, seeing as how the the AFR gets too rich on boost, especially if you are running more than the puny stock 6psi. why not just disconnect the vac line going to the WUR?? its not like it will go lean.
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Cedric
Joined: 27 Aug 2004
Posts: 2805
Location: Sweden
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| Posted: Sun Aug 29, 2021 7:06 am Post subject: |
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In standard form you need it, at least on the row cars. With ic and turbo change its a different story, i had to disconnect mine to get god afrs.
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MikeDanger
Joined: 21 Nov 2002
Posts: 774
Location: Denver
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| Posted: Fri Oct 29, 2021 7:55 am Post subject: |
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| Cedric wrote: | | In standard form you need it, at least on the row cars. With ic and turbo change its a different story, i had to disconnect mine to get god afrs. |
Hrmmm, well it didnt work, was richer at idle/mid range, and still too rich under boost.
I think it's the boost enrichment switch on the throttle. Can I just cut the wire?
as soon as i got WOT im getting 10 to 9 afr.
also HOW does the throttle switch enrich the mixture? does it activate the frequency valve or the start up injector?
On the other hand maybe I should ADD boost? Im at 11psi now, and with the IC, the intake temps (measured just in front of the TB) are pretty much the same as the OAT.
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MikeDanger
Joined: 21 Nov 2002
Posts: 774
Location: Denver
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| Posted: Fri Oct 29, 2021 10:38 am Post subject: |
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I remembered I had a Spare TPS so i took the cover off heres what it looks like:
Can anyone explain it? and what it controls exactly? watching the contacts move as I rotate it, I can tell the middle contact (that goes to the right) is the one for the WOT position. but what do the other contacts do? they both OPEN after about 10 of rotation
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Carrera RSR
Joined: 08 Jan 2010
Posts: 2312
Location: Somerset, UK
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| Posted: Fri Oct 29, 2021 5:25 pm Post subject: |
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TPS switch is just an on/off switch. I have next to no understanding of DITC as I have an S1. But I think it just controls idle or open throttle curve? I may be wrong, but nothing else?
If you are having too much fuel, its nothing to do with the boost enrichment on the WUR, its the WUR set up from scratch you need to tune. Best get yourself an adjustable WUR, AFR gauge, intake temp sensor and a dyno session to tune it all up properly. Then, if you cannot tune out the mid range richness, maybe use some solenoid switch set up to cut enrichment until you need the fuel at the top end, or as Cedric did on his, pull the boost signal off the WUR. I went the controlled way and a solenoid switch cuts the boost signal until 4600rpm then opens so I get full fuel on full boost + WOT from 4600rpm onwards. I can tune when or not the boost signal hits the WUR to avoid going too lean. The WUR delivers more than enough fuel in the low half and needs all the help it can get in the top end. The ignition curve is also tuned to match fuelling and avoid detonation. But its all on a knife edge.
Currently my car is a touch rich at the low end and a touch lean at the top end, I've reached the limit of CIS controllability. The WUR and fuel dizzy are fully adjusted and opened up to full fuel flow, boost @1.1bar, fully adjusted ignition curve. So all that equals 270bhp on the dyno before 6000rpm. My work is done.
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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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Cedric
Joined: 27 Aug 2004
Posts: 2805
Location: Sweden
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| Posted: Fri Oct 29, 2021 9:48 pm Post subject: |
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It's a us tps,,and yes it affects the full load enrichment according to the factory documentation, always good to read there 
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Carrera RSR
Joined: 08 Jan 2010
Posts: 2312
Location: Somerset, UK
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| Posted: Fri Oct 29, 2021 11:24 pm Post subject: |
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Damn US v RoW differences  
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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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Cedric
Joined: 27 Aug 2004
Posts: 2805
Location: Sweden
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| Posted: Fri Oct 29, 2021 11:49 pm Post subject: |
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| Carrera RSR wrote: | | Damn US v RoW differences |
Hehe  , they really are completely different animals, actually with very little in common in some ways to the row cars.
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MikeDanger
Joined: 21 Nov 2002
Posts: 774
Location: Denver
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| Posted: Sat Oct 30, 2021 7:15 am Post subject: |
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well that is diagram is for an s1, yes the s1 has 2 separate microswitches but the s2 has what I picture above.
does anyone know how the "enrichment" happens?
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MikeDanger
Joined: 21 Nov 2002
Posts: 774
Location: Denver
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| Posted: Sat Oct 30, 2021 7:30 am Post subject: |
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| Carrera RSR wrote: | TPS switch is just an on/off switch. I have next to no understanding of DITC as I have an S1. But I think it just controls idle or open throttle curve? I may be wrong, but nothing else?
If you are having too much fuel, its nothing to do with the boost enrichment on the WUR, its the WUR set up from scratch you need to tune. Best get yourself an adjustable WUR, AFR gauge, intake temp sensor and a dyno session to tune it all up properly. Then, if you cannot tune out the mid range richness, maybe use some solenoid switch set up to cut enrichment until you need the fuel at the top end, or as Cedric did on his, pull the boost signal off the WUR. I went the controlled way and a solenoid switch cuts the boost signal until 4600rpm then opens so I get full fuel on full boost + WOT from 4600rpm onwards. I can tune when or not the boost signal hits the WUR to avoid going too lean. The WUR delivers more than enough fuel in the low half and needs all the help it can get in the top end. The ignition curve is also tuned to match fuelling and avoid detonation. But its all on a knife edge.
Currently my car is a touch rich at the low end and a touch lean at the top end, I've reached the limit of CIS controllability. The WUR and fuel dizzy are fully adjusted and opened up to full fuel flow, boost @1.1bar, fully adjusted ignition curve. So all that equals 270bhp on the dyno before 6000rpm. My work is done. |
I already have an IC/intake temp/boost/WB/boost controller and Dual Adjustable WUR
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Carrera RSR
Joined: 08 Jan 2010
Posts: 2312
Location: Somerset, UK
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| Posted: Sat Oct 30, 2021 8:00 am Post subject: |
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Have you tuned it on the dyno? With and without the boost line attached to the wur? What was the results?
_________________
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 |
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MikeDanger
Joined: 21 Nov 2002
Posts: 774
Location: Denver
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| Posted: Sat Oct 30, 2021 8:36 am Post subject: |
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| Carrera RSR wrote: | | Have you tuned it on the dyno? With and without the boost line attached to the wur? What was the results? |
dyno is not worth it for CIS, when I swap to EFI I will.
As I said, performance was worse with the, WUR line removed.
I actually installed a Vac checkvalve off a 944 (from the brake booster) and it was a little better, but the WOT switch just makes it way to rich.
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Carrera RSR
Joined: 08 Jan 2010
Posts: 2312
Location: Somerset, UK
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| Posted: Sat Oct 30, 2021 4:47 pm Post subject: |
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Sounds like the wur is over fuelling regardless of boost enrichment. Whack up the boost to the max and use up all the fuel. What can go wrong!?
_________________
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 |
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