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Brando
 
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Fuel pressures and afr

So I gut a leask worm up regulator and wanted to instal it. Got me a set of fuel pressure tools that I could use to make the adjustments.
My system has one fuel pump, and it's an 044 Bosch up front (911vin car)
First of all, my afrs for my current wur are as follows:
Idle. 12.1
3krpm 15.5
Slight load up a hill. 15.7
Full boost. 11.1
And these are approximate.
Then I installed the adjustable wur and attached the gauges to check pressures.
My system was in spec at 87 psi. And my control ales was I. Spec at first but then I felt like my Chinese gauge set went south and no longer gave good readings so my made sense. It looked at first like my wur wasn't heating but I had voltage to the plug. No change in control pressure with time. Bad gauges maybe.
So screw the adjustment part. I'll just use the wur as us but the adjustments were very similar to my old one. Only real change was full boost dipped way rich inti the 9's which my car just cut out.

Why does everyone else have better afr's during cruise and idle than me?
I get high EGT numbers at slight load like going up a hill or sustained 90mph driving (1550*) because my afr is super lean when driving like that. Dangerous.
Thanks.
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Old 03-06-2014, 07:21 AM
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i am in the mid 15's at cruise. well i was. i need to check that again since i now think i have my air leaks fixed.
what do you have for a WG? mine had an air leak past the valve guide. i also had intake leaks

when i had an air leak i could run my idle as rich as upper 11'slow 12's and no surging,
hint hint.
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86 930 42kmiles [__] RUNNING:[__] NOT RUNNING: ____77 911S widebody: SOLD
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Old 03-07-2014, 04:56 AM
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Porsche did a pretty good job selecting a CPR for the 930. it has control well beyond the factory tune. It also has a press fit pin that you could carefully measure and adjust pressures but it is a bit complicated unless you mod the pin. Everytime one of those things come into this shop the afr's are whacked. I run the stock CPR and boost at 1.2 bar with near perfect afr's. the only non-stock item in my fuel system is the two 044's. Too many people use this BL unit and there is something else wrong. I'm straightening an 89 out in here today and the client wants to retain the BL unit although I couldn't get it tuned right. I swapped a brand new CPR on it yesterday and tuned the mix and it was almost perfect for the little time I spent on it, but he wants the BL back on today. These cars are easy to mod, headers, turbo etc. but with solid tuning, the simpler the better.
Old 03-07-2014, 05:24 AM
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what do you consider perfect AFR's?

idle
cruise
boost

do you understand the BL WUR?
if you just move the pin on the WUR that changes both boost AFR AND cruise AFR.
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86 930 42kmiles [__] RUNNING:[__] NOT RUNNING: ____77 911S widebody: SOLD
88 BMW 325is 200K+ SOLD
05 BMW 330CI 130K:: [__] RUNNING: [__] NOT RUNNING:
08 VOLVO V70 190K:: [__] RUNNING: [__] NOT RUNNING:
90 B2200[__] RUNNING:[] NOT RUNNING:__2000 MER E320 WAGON [] WRECKED:[]RUNNING:
Old 03-07-2014, 06:22 AM
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I understand all of it pretty well. These old 911's are the way I make my living. Also I didn't say I recommended fiddling with that pin. What I said was with these machines, in some cases, it is best left alone and we should solve certain issues within the parameters of the original engineering...or go EFI if that doesn't suit one's needs. We should remember what Porsche did themselves when extracting reliable power from these cars in the beginning. I have built and tuned EFI and turbo systems on everything ranging from a twin turbo 69 Camaro(I know lol) to 1000hp Supras, but when it comes to these ol' girls unless you want 500+ and a perfect idle you can get along fine with the stock components sans minor tweaking and some bolt on's. And BTW my idea of a perfect Afr scenario is one that doesn't blow your engine and leaves little to no HP/torque on the table. Mine runs 14.2-14.5 idle 14.6-15.1 part and 11.7-8's steady to the red, makes 437 hp at the wheels and has stock fuel system with the exception of 2 044 pumps. Turbo is gt3582r cheap headers, custom IC. a 2 stage manual controller and a spec 3 clutch making sure it all gets to the ground. Oh, almost forgot, a new factory CPR.

Last edited by Nuen Werke; 03-07-2014 at 10:01 AM.. Reason: spelled "no" WRONG...DUH!
Old 03-07-2014, 08:23 AM
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Brando
 
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I do not understand the wur, I mean I do but I don't, I'm not too proud to admit that.
Simple question is this:
Why are my afr's off? You think it's a leak? Could the heater circuit cause it? What?
Old 03-07-2014, 10:48 AM
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Quattro did you log your AFR's after the adj. CPR install? If so please list them, preferably one with you holding her in 3rd at 5k for a few seconds and see what that reading is.
Old 03-07-2014, 11:04 AM
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Brando
 
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Quote:
Quattro did you log your AFR's after the adj. CPR install? If so please list them, preferably one with you holding her in 3rd at 5k for a few seconds and see what that reading is.
No they were similar to my original wur but rich boost afr so I switched back to the original non adjustable wur.
Old 03-07-2014, 11:15 AM
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Same issue with this 89 slant in here.
Old 03-07-2014, 03:30 PM
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The BL mod makes it very easy to adjust cold, warm, and "full throttle" pressures. It takes some time but it isn't rocket science. Sure, a brand new WUR/CPR would be close to perfect. But, most of us can't get our hands on those for a price that is commensurate with our cars.
Old 03-07-2014, 05:45 PM
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Brando
 
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I'm sure the adjustable regulator will work. I don't really want to get into a debate about that....just want to get some idea about the reasons for my issues?
Old 03-07-2014, 06:11 PM
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Brando, isn't your lean cruise AFR due to too high warm control pressure? You could lower that via your new WUR then set idle AFR to 13.5 by way of the fuel head mixture plunger, and raise full enrichment control pressure until you get your desired full boost AFR. Is that what you are asking about?
Old 03-07-2014, 06:22 PM
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Brando
 
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It's not exactly what I was asking but it's good usable info that I need. Thanks. I'll do that when i get it back into the car.
Old 03-07-2014, 06:26 PM
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No problem, Brando. Can you write again what specifically you are asking about? I can't exactly understand by your first post, but would like to.
Old 03-07-2014, 07:27 PM
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Brando
 
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Sorry, I was out of town doing my pelican stuff on the phone. That's not fun. And I already dont spel gud.

Anyway, I guess my questions are confusing because I have two issues I'd like to tackle..
1) my afr's are odd. They're as seen above and I wanted to fix that with a new and adjustable wur but my gage set only complicated things. And the newer adjustable wur acted very similarly to my origional wur other than the full throttle enrichment stated above. Do I have a leak that might cause the odd afr or has others seen this type of anomaly? My sustem is simple with no aar or decel and everything is pretty new..I can't figure out how it would be leaking..
2) I have the instructions from leask but would LOVE some input/pointers in adjusting it. Like little ideas as to how it worked for you etc..
thanks
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Old 03-07-2014, 07:39 PM
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Quote:
Originally Posted by Nuen Werke View Post
I understand all of it pretty well. These old 911's are the way I make my living. Also I didn't say I recommended fiddling with that pin. What I said was with these machines, in some cases, it is best left alone and we should solve certain issues within the parameters of the original engineering...or go EFI if that doesn't suit one's needs. We should remember what Porsche did themselves when extracting reliable power from these cars in the beginning.
Firstly, there are a lot of people who understand these cars here on this board so you are not alone.
Secondly, I would agree that a stock, well functioning wur is fine for a stock engine at stock boost. Anything that increases mass flow through the engine requires compensation in the way of increased fuel delivery. An adjustable wur is a legitimate way to accomplish this. It's not preferred method for fueling big hp builds but it has been proven time and time again for mild to moderate mods. Tuning a Turbo engine with an adjustable wur isn't any different conceptually than changing jets on a Camaro carburetor, only CIS is much more effective across the spectrum of engine running conditions than a carburetor is.
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Old 03-08-2014, 03:27 AM
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Many moons ago, I started a thread to collect data logs. I figured it could be a real useful reference for us DIY idiots...at least provide some objective data as a repsonse to that age old question "what are ideal afrs"

Only one person responded...and my 'genius' idea of a database here has exactly ONE data point: mine.

Ultimate Datalog Thread - post your logs here

Maybe it's useful for you guys...
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Old 03-08-2014, 05:51 AM
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Set your fancy AFR numbers aside for a short time... hook up your "chinese" fuel gauges again and get yourself four measurements to start with. System pressure, cold pressure, warm pressure and full throttle enrichment. You need these four numbers to make sure that you are at least in a good gross starting point. After that, you can dink around with the CO adjuster and tweak your pressures slightly for optimum AFR. But at this point it sounds like you are not confident in your WUR so your AFRs will never be repeatable.
There are all kinds of write ups here but you asked for tricks...
1. hook up battery charger
1a. hook up pressure gauges
2. unplug wur heater connector
3. write down system pressure and then cold pressure numbers, compare to spec
4. plug in heater connector, let pumps run for about 5 minutes, write down warm pressure
5. put 7 or 8 psi into the WUR boost nipple and you should see the fuel pressure drop (the trick here is to not over pressure the WUR and blow up the diaphragm... use a brake bleeder pump to add pressure very slowly), write down the full throttle enrichment reading
Once you have those numbers you will know how to attack the adj WUR. My guess, based on your original post, is that your "full throttle enrichment" measurement will be much less than the 2.9bar that is in the spec. That is an easy adjustment depending on which version of the BL you have.
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Old 03-08-2014, 06:03 AM
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Quote:
Originally Posted by jwasbury View Post
Many moons ago, I started a thread to collect data logs. I figured it could be a real useful reference for us DIY idiots...at least provide some objective data as a repsonse to that age old question "what are ideal afrs"

Only one person responded...and my 'genius' idea of a database here has exactly ONE data point: mine.

Ultimate Datalog Thread - post your logs here

Maybe it's useful for you guys...
Thanks for the re-post. Good stuff. I never did get around to hooking up my laptop to my Innovate setup (didn't have the right cable) so any monitoring I did was via my right eye while watching the road with my left. I like seeing this real-time stuff vs. from a dyno run.
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Old 03-08-2014, 06:24 AM
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Brando
 
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Quote:
Originally Posted by DSPTurtle View Post
Set your fancy AFR numbers aside for a short time... hook up your "chinese" fuel gauges again and get yourself four measurements to start with. System pressure, cold pressure, warm pressure and full throttle enrichment. You need these four numbers to make sure that you are at least in a good gross starting point. After that, you can dink around with the CO adjuster and tweak your pressures slightly for optimum AFR. But at this point it sounds like you are not confident in your WUR so your AFRs will never be repeatable.
There are all kinds of write ups here but you asked for tricks...
1. hook up battery charger
1a. hook up pressure gauges
2. unplug wur heater connector
3. write down system pressure and then cold pressure numbers, compare to spec
4. plug in heater connector, let pumps run for about 5 minutes, write down warm pressure
5. put 7 or 8 psi into the WUR boost nipple and you should see the fuel pressure drop (the trick here is to not over pressure the WUR and blow up the diaphragm... use a brake bleeder pump to add pressure very slowly), write down the full throttle enrichment reading
Once you have those numbers you will know how to attack the adj WUR. My guess, based on your original post, is that your "full throttle enrichment" measurement will be much less than the 2.9bar that is in the spec. That is an easy adjustment depending on which version of the BL you have.
Thanks, I'll try this again today, these are similar instructions if not exactly the same as I have, which are understandable.
But, as another question about that mityvac, it's a vacuum pump not a pressure pump, how do I apply pressure from a vacuum pump? I got one (a mityvac as prescribed) and I can't logically figure out how vacuum can translate into pressure? Am I stupid?
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Old 03-08-2014, 06:52 AM
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