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Old 04-22-2010, 07:09 PM   #51
procainestart
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Quote:
Originally Posted by casioqv View Post
It seems like nobody knows which potentiometer to adjust to raise boost- some places say F, and others say P.... Anyone have any more definitive info?
Note that all boost values noted below are for SAABs. You will have to take it on faith that the guy who wrote this is as reliable a source as you'll find on the internet.

Quote:
Originally Posted by KevinK, former Saab 900T owner, professional engineer
Most people/sites suggest that to crank up the boost you
just turn in the 'P' screw in the ECU. Unfortunately this myth
was supported by a Winkler article in Nines. Based on
extensive testing on my 83T over many years, I believe the
proper way is to turn in the 'F' , and then turn in the
adjacent 'P' screw a little as a fine tune. The 16V's, up to
M93, have essentially the same system.

The screws (ie., pots, potentiometers) are as follows:

P = Percent................ solenoid 'default' duty cycle

F = Full boost ............ max boost vs rpm map

K = Knock ..................sensor sensitivity

Below about 5-6 psi and under 3100 rpm (and at idle), the
solenoid valve is 95% open, bleeding off the waste gate
actuator to keep it closed. Once either of these limits is
exceeded, the solenoid valve changes to a 'default' duty
cycle, set by the 'P' screw. This partly closes the valve,
and reduces the rate at which pressurized air is bled off
the actuator.

This allows the WG to crack open and slow down how
quickly the boost rises, all to avoid pressure spikes and
severe overshoot.

THE 'F' SCREW sets the max pressure allowed before
the solenoid valve quickly changes from the default 'P'
duty cycle to a more closed condition in an 'active control'
mode. This feeds more pressurized air into the actuator to
open the WG more and reduce boost.

The pressure map for my 83T is flat up to 3100 rpm, and
from there it tapers down 2.5 psi by 5500 rpm. If I turn F in
fully, the controlled max limit is 12.5 psi up to 3100 rpm,
dropping to 10 psi by 5500 rpm ( the 16V max F map
should be higher).

I'm currently going easy on the 2nd trans with F set to 10
psi, dropping to 7.5 psi at 5500 rpm.

THE 'P' SCREW trims the rate at which boost rises. I
found that turning in the P too much results in excess
overshoot, and an annoying run-away boost climb with just
slight pedal depression in upper gears. However, if F is
turned in (increased) without increasing P, then the
P-default will open the WG before the higher F limit is
reached, and no significant boost increase is achieved. A
relatively low 'P' setting limits higher rpm boost.

Only tweak an in-tune engine with good plugs and wires,
etc. First step is to be sure the basic boost is set at the
actuator rod. Set it per the manual to about 45-50% of
your desired max running boost. If you plan on a lot of time
at high rpm, intake and exhaust should be upgraded.

For 8V turbos with CIS injection, you can add an IC, but
the stock fuel system does not provide enough richness to
support higher boost without detonation.

For pre M89, the trans has a small pinion bearing that fails
often at stock boost levels.

For US 16V engines, the 2.5 FPR should be upgraded to
2.8 (or 3.0) if mid-red boost levels are desired.

Mark/note your starting position of the screws. If you
already messed with the P, turn it fully in and back it out
1/3 turn. Increase boost by turning in F a lot and P a little.
Hard core will turn in F fully, but the P is the boost-rise
rate, and should not be turned in too much for reasons
noted prevoiusly. The P takes some time to get right, and
winds up being a 'little nudge' type final adjustment. All
knock sensor control is left in operation.

Don't mess with 'K'.

If you max out F and want more, a Radio Shack 430-ohm
resistor, across the pressure sensor terminals, will get you
about 3 more psi. I put in a Mad-Max switch on the
console to kick in the resistor when I want to go from my
10 psi setting to 13 psi. A 530 ohm resistor is closer to a
2 psi kick. I also moved my pressure supply for the
solenoid valve from the turbo to the throttle body, but
before the throttle valve. This tends to slightly increase
high rpm boost, when in 'P default' mode, and is related to
the 1-2 psi pressure drop (at high flow) at the very
restricting stock 16V intercooler and piping
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Old 04-22-2010, 07:29 PM   #52
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Quote:
Originally Posted by cargod78 View Post
with the APC system do you adjust the boost or does it just keep cranking it up till it gets knock?
The APC controls (a) the RATE at which boost rises (and drops at high RPM), (b) the TOTAL boost, and (c) pressure release upon sensing KNOCK.

To be clear, the APC does NOT simply let the boost rise until it detects knock, and it is not connected to either spark timing or fuel (Jetronic ECU).

Earlier in this thread there were questions about 9000 APCs. You can use an APC from any Saab 9000 Turbo that has a *distributor* (Jetronic LH2.2 or 2.4). If the head has no distr. and a red Direct Ignition cassette bolted into it (above the spark plugs), then you cannot use the car's APC on your Volvo. (It's actually a DI/APC system that controls both timing and boost; it cannot be run as a boost controller only.)
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Old 04-22-2010, 07:43 PM   #53
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Playing with the APC system is really fun! Mine seems to correlate with what procainestart said- it "spikes" to about 12psi, and then tapers to about 10psi at higher rpms with the stock adjustments.

Do you guys think it causes damage to the engine during the brief periods when the engine knocks, before the boost is reduced? Or is it important to always try and tune the APC to avoid all knock? It seems like the Saabs must have been designed to (and survive) running in a condition when the APC is constantly pulling back boost if the stock boost is over 12psi, and the driver were to put in low octane gas (for example).

Last edited by casioqv; 04-22-2010 at 07:54 PM..
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Old 06-21-2010, 05:55 PM   #54
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For a clean install
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Old 06-26-2010, 11:44 AM   #55
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As neat as it is, I hated the stock APC in my 86 9Kt, even after some of the run of the mill box mods to make it pull(less) boost in the upper rpm's. It's great for if your mother drives it or something to keep them from pinging it to death or such, but the plain mechanical system in my 745t felt so much better.
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Old 01-16-2011, 06:05 PM   #56
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Really, really excited to get my APC system installed!

Scored a mega-deal off eBay, and got a complete system for less than I would have paid PnP, + my time and gas.

So, the "C" port on the APC is to go to the cold side of the turbo? "W" to wastegate and the "R" to a port just after my AMM...what do you all do to make a port post AMM?

Thinking that I'll mount the APC on the shock tower, just next to the radiator overflow tank...seems the cleanest spot.

Where does the Pressure Transducer go?
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Old 01-22-2011, 02:22 AM   #57
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So, got my wires for my engine harness cleaned up...now it's on to wiring up my APC system.

Gonna locate the APC box on the coil mount bracket on the driver shock tower...where the chrysler ignition box would normally be.

Wiring seems fairly straight forward...I'll start asking more questions when I get closer.

For now, I'm wondering where the Pressure Transducer get's it's vacuum from. I didn't pull the system personally, got hooked up PHAT on eBay, so didn't have the first hand oppertunity to follow the vacuum hose to where it connected to. I assume it goes to the intake...get's its read out to send to the computer and the computer controls the 3-way valve, which is connected to the turbo cold side, wastegate and to a bung I'll have to make, post AMM?
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Old 01-22-2011, 02:41 AM   #58
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Quote:
Originally Posted by Mylesofsmyles View Post
I assume it goes to the intake...get's its read out to send to the computer and the computer controls the 3-way valve, which is connected to the turbo cold side, wastegate and to a bung I'll have to make, post AMM?
Correct- just T the transducer into your boost gauge line. I think there's a good safety benefit of this too, because if the transducer line pops of, gets chafed, etc. you'll notice immediately that your gauge isn't working before it overboosts.

You don't really need a bung, you can just drill a hole slightly smaller than the hose in the rubber AMM to turbo hose and shove it through.
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Old 01-22-2011, 02:51 AM   #59
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Quote:
Originally Posted by casioqv View Post
Correct- just T the transducer into your boost gauge line. I think there's a good safety benefit of this too, because if the transducer line pops of, gets chafed, etc. you'll notice immediately that your gauge isn't working before it overboosts.

You don't really need a bung, you can just drill a hole slightly smaller than the hose in the rubber AMM to turbo hose and shove it through.
i've got the aluminum 740 intercooler plumbing...i think i'll figure out a more permanent solution than just dropping the line as you're describing...maybe just find another hard elbow with a vacuum bung already there...someone must have made one for some car at some time, no?

kk, sounds like I'm not quite ready to install this...gotta take a few more prep steps, I guess.

gotta still plumb my new air box and intercooler, to see how that changes my intake tubing, first.
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Old 01-22-2011, 12:16 PM   #60
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Quote:
Originally Posted by Mylesofsmyles View Post
i've got the aluminum 740 intercooler plumbing...i think i'll figure out a more permanent solution than just dropping the line as you're describing...maybe just find another hard elbow with a vacuum bung already there...someone must have made one for some car at some time, no?
You could tap it 1/4 npt and add a brass nipple.

The IBC conversion does mention 'dropping' a line into the elbow,and the intercooled cars had the same setup with a factory cast hole.
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Old 01-22-2011, 12:37 PM   #61
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Quote:
Originally Posted by Redwood Chair View Post
You could tap it 1/4 npt and add a brass nipple.

The IBC conversion does mention 'dropping' a line into the elbow,and the intercooled cars had the same setup with a factory cast hole.
so just throw a line down the fishing well?
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Old 01-22-2011, 01:53 PM   #62
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hotdog down a hallway.

Actuallly I prefer the tap and barb install, cleaner, more permanent, less chance of fail.
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Old 01-22-2011, 02:57 PM   #63
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Quote:
Originally Posted by Mylesofsmyles View Post
so just throw a line down the fishing well?
Sort of but not really according to the factory instructions.
See step#21

http://www.k-jet.org/files/installat...structions.pdf

Quote:
Originally Posted by badvlvo View Post
hotdog down a hallway.
It was actually pretty hard to stuff the hose in there.

Quote:
Originally Posted by badvlvo View Post
Actuallly I prefer the tap and barb install, cleaner, more permanent, less chance of fail.
+1

Doing it right always pays off in the end.

Of course the cost of the drill bit and 1/4 npt tap would pretty much ruin the nightly beer budget.
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Old 01-22-2011, 03:59 PM   #64
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Quote:
Originally Posted by Mylesofsmyles View Post
i've got the aluminum 740 intercooler plumbing...i think i'll figure out a more permanent solution than just dropping the line as you're describing...
I don't think there's anything on an APC that can or should be connected to the intercooler pipes. The transducer should take a signal post throttle-body, and the "vent" (rightmost port on solenoid valve from the top) should connect before the turbo where it's exposed to ambient pressure.
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Old 01-22-2011, 04:00 PM   #65
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I've got an APC black box if anyone wants a spare PM me. $20 + shipping and its yours.
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Old 01-22-2011, 05:32 PM   #66
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Quote:
Originally Posted by casioqv View Post
I don't think there's anything on an APC that can or should be connected to the intercooler pipes. The transducer should take a signal post throttle-body, and the "vent" (rightmost port on solenoid valve from the top) should connect before the turbo where it's exposed to ambient pressure.

right...good point. the intercooler pipes are post turbo, and this needs to be pre-turbo.

think I'm going to do what Ken's suggesting and drill a hole and permanently mount a bung.

i don't know why that seemed so tough to begin with.


Also want to confirm that the instructions in the first post of this thread are right...in terms of wiring.

Though it doesn't specify where to wire the leads from the knock sensor to.


As for the knock sensor...is it best to run a separate knock sensor or can I just piggy back the leads to the existing sensor on my B230FT
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Old 01-22-2011, 05:35 PM   #67
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APC hacking




Electronic "knock hat" listen to your engine while driving, the Saab APC has a circuit that listens for engine noise to verify that the knock sensor is functional, added option to listen in with a headphone. Here i connected a piezzo speaker so the engine noise could be heard on my video.

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Old 01-22-2011, 10:31 PM   #68
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i can't really say i know what i was hearing but cool for you for posting those vids!

what was going on in the first one?
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Old 01-22-2011, 10:45 PM   #69
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Quote:
Originally Posted by Mylesofsmyles View Post
i can't really say i know what i was hearing but cool for you for posting those vids!

what was going on in the first one?
I was scratching and tapping the knock sensor to simulate engine noise
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Old 01-22-2011, 11:42 PM   #70
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Quote:
Originally Posted by Mylesofsmyles View Post
think I'm going to do what Ken's suggesting and drill a hole and permanently mount a bung.

i don't know why that seemed so tough to begin with.
I still have those brass nipples we took off your B21F manifold.

Drills and the taps are here too,check in some time,and we'll get it going.
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Old 01-23-2011, 02:47 AM   #71
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I still have those brass nipples we took off your B21F manifold.

Drills and the taps are here too,check in some time,and we'll get it going.

coolio dude...should be smooth with your attention to detail at hand. I think that's the last of my riddles.

oh, and where to run the leads to the knock sensor to...meaning what are the pin outs for the knock sensor....

never mind, found the leads, still intact.
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Old 01-27-2011, 05:11 AM   #72
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Originally Posted by Mylesofsmyles View Post
never mind, found the leads, still intact.
Yea, the wiring instructions usually don't mention the knock sensor wiring, because it's a shielded cable and works best if you pull the whole thing and use it untouched. You can piggy back off the same sensor with the adapter sold for knocksense, but it's easier just to get a longer bolt and have two.
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Old 01-27-2011, 01:03 PM   #73
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Easier or smarter? Doesn't seem too hard to piggyback the existing knock sensor.

Any drawbacks to this?
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Old 01-27-2011, 03:45 PM   #74
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Quote:
Originally Posted by Mylesofsmyles View Post
Easier or smarter? Doesn't seem too hard to piggyback the existing knock sensor.

Any drawbacks to this?
Not if the wiring is still shielded properly (although if it weren't it would *probably* still work). If I were to go that route, I'd buy a knocksense harness from Borris- otherwise you'd have to either find the correct connectors or permanently cut into your stock EZK harness:

http://www.viatrack.ca/

I just used an old Volvo exhaust stud, nut, and washer in place of the stock bolt to piggy back a second sensor.
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Old 01-27-2011, 05:53 PM   #75
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So its totally cool to double up on the sensors?
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