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CorsePerVita
Joined: 25 Jul 2008
Posts: 1992
Location: Redmond, Oregon
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 Posted: Sun Aug 10, 2014 2:35 pm Post subject: Well, I found my terrible mileage issues. |
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My mileage has been absolutely horrid lately with some quirky running issues. Installed a wideband system so I can finally pinpoint and log my mixture. My first observation at highway speeds with random cutting out and flooding out... Just a LITTLE on the rich side.
Ok, a lot.
So I went ahead and recorded my logging data and plugged my laptop in and recorded 15 minutes of driving. My average fuel ratio for a while was 10-12. I eventually got it a bit more desirable and it is now happily at 14.5 idle with a 13.5 highway with a 12 under load. Feels WAY more responsive, plugs look more normal.
I may lean it out just a hair more, but man, you barely BARELY need to tweak on the mixture to make any difference. Keeping my allen wrench and 8mm wrench on me so I can drive again tomorrow.
What a difference! Nice to see how the O2 levels out on idle, not having to deal with any major dips. I'm not seeing any crazy hiccups in the O2 measurements maintaining load or anything. So that thus far seems to tell me that I'm not dealing with intermittent fuel pump issues. Here's a few screenshots of before and after.
My most recent adjustment
My first adjustment (obviously more rich)
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- 1977 Porsche 924 2.0 N/A (Trackday Project)
- 1979 Porsche 924 2.0 N/A (The other daily)
- 1980 Porsche 931 (Daily)
- 1987 Lamborghini Jalpa
- 1999 Ducati 900SS |
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morghen
Joined: 21 Jan 2005
Posts: 8880
Location: Romania
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| Posted: Sun Aug 10, 2014 6:08 pm Post subject: |
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AFR tuning has never been easier 
I installed a permanent wideband and gauge in my red turbo, its a great thing to have on an old car.
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CorsePerVita
Joined: 25 Jul 2008
Posts: 1992
Location: Redmond, Oregon
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| Posted: Sun Aug 10, 2014 10:21 pm Post subject: |
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| morghen wrote: | AFR tuning has never been easier
I installed a permanent wideband and gauge in my red turbo, its a great thing to have on an old car. |
Yep this is a permanent solution and not just a tail sniffer. That said, I realize I should be even a bit more lean than this but for now, it works much better than it was.
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- 1977 Porsche 924 2.0 N/A (Trackday Project)
- 1979 Porsche 924 2.0 N/A (The other daily)
- 1980 Porsche 931 (Daily)
- 1987 Lamborghini Jalpa
- 1999 Ducati 900SS |
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CorsePerVita
Joined: 25 Jul 2008
Posts: 1992
Location: Redmond, Oregon
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| Posted: Mon Aug 11, 2014 11:34 pm Post subject: |
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Another morning tuning session on the way to work. Plugged in the laptop the whole drive to work and played with the mixture on the way. Thus far, very happy with the results. The 931 is starting to really feel great. Very responsive now, doesn't feel like I'm pouring 50 gallons of gas down her throat when I get on it.
Pulls harder, pulls more efficiently. And I'll be damned if I'm not getting better mileage (by a lot).
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- 1977 Porsche 924 2.0 N/A (Trackday Project)
- 1979 Porsche 924 2.0 N/A (The other daily)
- 1980 Porsche 931 (Daily)
- 1987 Lamborghini Jalpa
- 1999 Ducati 900SS |
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morghen
Joined: 21 Jan 2005
Posts: 8880
Location: Romania
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| Posted: Tue Aug 12, 2014 3:24 am Post subject: |
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Oh so this is a 931 we are talking about.
Carefull 14.5 is too lean you will get detonation if you push it hard.
I follow these rules(CIS simply behaves like that if you set the right mixture):
cruising at 0.2 vacuum = AFR 13.5
any boost increase = richer mixture instantly
2200 RPM @ 0.2 bar = 12.5 AFR
3500 RPM @ 0.8bar = 11.5 AFR
4000 RPM and above @ 1.1 bar = 10.5 AFR
Thus far everything is fine and i've driven fast a few times.
I also get solid 8L/100km mileage with sporty driving, thats 29-30MPG depending on how fast i go.
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CorsePerVita
Joined: 25 Jul 2008
Posts: 1992
Location: Redmond, Oregon
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| Posted: Tue Aug 12, 2014 3:27 am Post subject: |
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| morghen wrote: | Oh so this is a 931 we are talking about.
Carefull 14.5 is too lean you will get detonation if you push it hard.
I follow these rules(CIS simply behaves like that if you set the right mixture):
cruising at 0.2 vacuum = AFR 13.5
any boost increase = richer mixture instantly
2200 RPM @ 0.2 bar = 12.5 AFR
3500 RPM @ 0.8bar = 11.5 AFR
4000 RPM and above @ 1.1 bar = 10.5 AFR
Thus far everything is fine and i've driven fast a few times.
I also get solid 8L/100km mileage with sporty driving, thats 29-30MPG depending on how fast i go. |
14.5 is when the car was at a dead stop idling.
Currently cruising is around 12.5-13.5
On it is closer to 11.
WOT is pretty close to 10.
So my numbers are pretty darn close.
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- 1977 Porsche 924 2.0 N/A (Trackday Project)
- 1979 Porsche 924 2.0 N/A (The other daily)
- 1980 Porsche 931 (Daily)
- 1987 Lamborghini Jalpa
- 1999 Ducati 900SS |
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Cedric
Joined: 27 Aug 2004
Posts: 2608
Location: Sweden
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| Posted: Tue Aug 12, 2014 4:55 am Post subject: |
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S2 engine with 2664G4.10 charger and s1 WG spring.
How have you choosen to adjust your fueling in your runs?
Hook up RPM as well, makes things a lot easier !
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1980 924 Turbo
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CorsePerVita
Joined: 25 Jul 2008
Posts: 1992
Location: Redmond, Oregon
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| Posted: Tue Aug 12, 2014 5:10 am Post subject: |
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| Cédric wrote: | S2 engine with 2664G4.10 charger and s1 WG spring.
How have you choosen to adjust your fueling in your runs?
Hook up RPM as well, makes things a lot easier ! |
I see that you've got your tachometer hooked up to yours. I'll admit I'm not entirely sure how to do that just yet. I've been adjusting mine after the car is completely warmed up at operating temperatures. It looks like I'm fairly close.
What method are you using to adjust yours?
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- 1977 Porsche 924 2.0 N/A (Trackday Project)
- 1979 Porsche 924 2.0 N/A (The other daily)
- 1980 Porsche 931 (Daily)
- 1987 Lamborghini Jalpa
- 1999 Ducati 900SS |
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Cedric
Joined: 27 Aug 2004
Posts: 2608
Location: Sweden
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| Posted: Tue Aug 12, 2014 5:41 am Post subject: |
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| CorsePerVita wrote: | | Cédric wrote: | S2 engine with 2664G4.10 charger and s1 WG spring.
How have you choosen to adjust your fueling in your runs?
Hook up RPM as well, makes things a lot easier ! |
I see that you've got your tachometer hooked up to yours. I'll admit I'm not entirely sure how to do that just yet. I've been adjusting mine after the car is completely warmed up at operating temperatures. It looks like I'm fairly close.
What method are you using to adjust yours? |
I use the innovate LM2, and it has a lot of inputs, I have a boost sensor as well, but have been to lazy to implement it
I changed the WUR (the old one ran way to lean triggering my knock sensor) and just made a slight shim change in the distributor to get it sliiigtly richer. Other than that is has just worked fine, maybe its time to take it out for a spin with the WB, this log is pretty old...
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1980 924 Turbo
www.instagram.com/garagecedric/ |
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CorsePerVita
Joined: 25 Jul 2008
Posts: 1992
Location: Redmond, Oregon
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| Posted: Tue Aug 12, 2014 5:47 am Post subject: |
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| Cédric wrote: | I use the innovate LM2, and it has a lot of inputs, I have a boost sensor as well, but have been to lazy to implement it
I changed the WUR (the old one ran way to lean triggering my knock sensor) and just made a slight shim change in the distributor to get it sliiigtly richer. Other than that is has just worked fine, maybe its time to take it out for a spin with the WB, this log is pretty old... |
Interesting, I've only had to make a very minor adjustment at the distributor on mine. I haven't had to change anything on the WUR.
_________________
- 1977 Porsche 924 2.0 N/A (Trackday Project)
- 1979 Porsche 924 2.0 N/A (The other daily)
- 1980 Porsche 931 (Daily)
- 1987 Lamborghini Jalpa
- 1999 Ducati 900SS |
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Cedric
Joined: 27 Aug 2004
Posts: 2608
Location: Sweden
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| Posted: Tue Aug 12, 2014 6:25 am Post subject: |
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| CorsePerVita wrote: | | Cédric wrote: | I use the innovate LM2, and it has a lot of inputs, I have a boost sensor as well, but have been to lazy to implement it
I changed the WUR (the old one ran way to lean triggering my knock sensor) and just made a slight shim change in the distributor to get it sliiigtly richer. Other than that is has just worked fine, maybe its time to take it out for a spin with the WB, this log is pretty old... |
Interesting, I've only had to make a very minor adjustment at the distributor on mine. I haven't had to change anything on the WUR. |
My WUR was broken, so thats probably why I had to change it
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1980 924 Turbo
www.instagram.com/garagecedric/ |
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924RACR
Joined: 29 Jul 2001
Posts: 8804
Location: Royal Oak, MI, USA
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| Posted: Tue Aug 19, 2014 10:33 pm Post subject: |
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Going back to this - cool stuff, and considering that I have all this stuff (WBO2 and data logger) sitting in my racecar (the prototype) collecting dust most of the time... I might have to get butt in gear and hook it up to my 931, get the thing dialed in once I get it running basically right and broken in...
Cool...
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'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype |
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morghen
Joined: 21 Jan 2005
Posts: 8880
Location: Romania
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| Posted: Tue Aug 19, 2014 11:30 pm Post subject: |
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A bit OT but my car has developed a weird simptom lately.
When cold it runs lean..way lean...14-15AFR lean at idle and will ofcourse not rev up properly, sputter and behave like an ass before its fully warmed up. After that its spot on with everything.
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Rasta Monsta
Joined: 12 Jul 2006
Posts: 11723
Location: PacNW
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| Posted: Wed Aug 20, 2014 1:11 am Post subject: |
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| morghen wrote: | cruising at 0.2 vacuum = AFR 13.5
any boost increase = richer mixture instantly
2200 RPM @ 0.2 bar = 12.5 AFR
3500 RPM @ 0.8bar = 11.5 AFR
4000 RPM and above @ 1.1 bar = 10.5 AFR |
As has been proven on the dyno by Brian Leask and others, this curve goes rich too soon for maximum power delivery.
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Toofah King Bad
- WeiBe (1987 924S 2.5t) - 931 S3
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DZGunner
Joined: 18 Nov 2014
Posts: 191
Location: Great white north
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| Posted: Thu Feb 12, 2015 10:37 am Post subject: |
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| Is that gauge the same dimensions as the holes our VDO gauges go into? I'm looking at what appears to be the same innovative wide band and display as you have and just wanted to know if it'd be a drop in fit. |
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