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Discussion Starter #1 (Edited)
hey again,

i was wondering, does anyone know how much fuel exactly is needed under boost? ill never be running more than 6psi max at any given time under boost.... also, i have a 3.0bar regulator if that helps...i jsut need to know to get my engine timed properly.

thanks
 

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i have 49 psi and idle and jumps to around 60-65 psi under boost, which is 19 pds. for 6 pds of boost i would say a 3.0 bar regulator will be fine. I also run a NA fuel pump which is more psi so your already ahead of the game.
 

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This makes NO sense.. OEM base boost should be approx 8psi Measured with a genuinely accurate Gauge or Halfway thru the yellow on your dash gauge.
You aren't even up to 'broken' APC system levels.
Up untill 16 psi Boost you need NO additional fueling beyond what Saab has provided.. Period.
A higher pressure Regulator causes an overrich idle and washes essential oil off of the cylinder walls... Fool Territory Mate.
Water injection and/or a decent Fuel control ECU is a far better route.
Costs Money Though :)
Wanna really know what's happening in there ?
install a wideband o2 sensor and the facility to read it in real time... results would surprise you.
 

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Basre said:
This makes NO sense.. OEM base boost should be approx 8psi Measured with a genuinely accurate Gauge or Halfway thru the yellow on your dash gauge.
You aren't even up to 'broken' APC system levels.
Up untill 16 psi Boost you need NO additional fueling beyond what Saab has provided.. Period.
A higher pressure Regulator causes an overrich idle and washes essential oil off of the cylinder walls... Fool Territory Mate.
Water injection and/or a decent Fuel control ECU is a far better route.
Costs Money Though :)
Wanna really know what's happening in there ?
install a wideband o2 sensor and the facility to read it in real time... results would surprise you.
I run a modified APC (16-17 psi) with a 3.0 bar FPR. No problems so far. Not much difference between a 2.8 vs 3.0 bar FPR, just a little safety up top.
 

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Maybe that explains it...

I notice my N/A 900 has a 3 bar FPR. I also notice the resistance of the AMM is about 700 ohm rather than the recommended 380 ohm. It has no O2 sensor. I wonder is the AMM set so high 'cos the FPR is pushing more fuel than necessary. And, does that mean that I'm using excessive fuel at idle or WOT since the airflow meter is not used for these bits?

Anyway, would it be a worthwhile thing to swap the 3 bar FPR to the LPT (which does have an O2 sensor) and but its standard one into the N/A?

Thoughts?
 

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Discussion Starter #6
ok well i switched the AMM, i used the one from my n/a set up, and the car just starts then dies, so i switched it back to the AMM that was in the '85 turbo and it works, but it just idle's high, its gets higher but wont idel more than about 1700rmp when it gets to normal operating temps. any other ideas? woudl a leaking fuel rail cause any of a difference in anything in terms of operation of the engine?
 

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I'm sorry but Am actually trying to help here... but your statements are basically undecipherable. Switched Amm's, Leaking Fuel Rail, 30Ohms Idle at 1700? Individually all have meaning when in detailed/descriptive context.. but total Gibberish in your statement.
One really needs to understand just what the problem is, in clear detail before any meanigfull diagnosis is even possible.
Obviously you must Fix the basic problems like Idle and 'barely' Base Boost before you need worry about Fuel enrichment.
Look at yr Exhaust pipe end.. it SHOULD be brown grey on any car that runs a Catalytic.. Variation from this indicates genuine problems.
Seriously suggest a Workshop Manual... Bentley is quite good.. but $50 usually :) but frankly Yer dead without it .
In it there are Tuneup procedures and a Base Boost Diagnosis.. Follow it to the Letter.. and you should get your car up to 10/11 psi (OEM levels).. The perf difference is Major... well worth the effort expense.
 

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Basre said:
I'm sorry but Am actually trying to help here... but your statements are basically undecipherable. Switched Amm's, Leaking Fuel Rail, 30Ohms Idle at 1700? Individually all have meaning when in detailed/descriptive context.. but total Gibberish in your statement.
One really needs to understand just what the problem is, in clear detail before any meanigfull diagnosis is even possible.
Obviously you must Fix the basic problems like Idle and 'barely' Base Boost before you need worry about Fuel enrichment.
Look at yr Exhaust pipe end.. it SHOULD be brown grey on any car that runs a Catalytic.. Variation from this indicates genuine problems.
Seriously suggest a Workshop Manual... Bentley is quite good.. but $50 usually :) but frankly Yer dead without it .
In it there are Tuneup procedures and a Base Boost Diagnosis.. Follow it to the Letter.. and you should get your car up to 10/11 psi (OEM levels).. The perf difference is Major... well worth the effort expense.
Basre,
Do you believe it is bad to run a 3.0 FPR vs the stock 2.8 FPR?
I think the difference is negligible especially at higher boost levels??
 

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Discussion Starter #9
Ok first of all, I don’t have a T16 from the factory; I turned my N/A to a LPT. I know its running rich because it's almost dieing when you give it too much gas at once. More or less, my question was to aim towards making the timing of my car for an FMU a lot easier. Secondly I never mentioned 30Ohms, I don’t even know what this means. I know it has to do with the AMM but it means nothing to me. I switched my AMM because I wanted to see if it would lower my idle, but instead it just dies.

My high idle speeds are due to the fact that my engine is running rich. It does not surpass 1700rmp at idle. I would have figured maybe a leaking fuel rail would have caused a problem somewhere, but that had nothing to do with it, ive switched it with one that is not leaking, and still the same problem.

Maybe this was my mistake by not making it clear that I DO NOT have a factory T16, but my 900 is a mod I have created to be an LPT, but my question overall was just to know a ball parked figure, nothing specific, but just how much fuel was needed under boost?!
Like I said, my reasons were because I wanted to install a fuel management unit(FMU) simply because I did not want to buy the larger injectors from a T16, when I had a FMU laying around.

I know what the problem is. How do i fix it is what im working on and thats why i turned to this forum, just like everyone ealse on this site. The car has not been running long enough to be able to determine the color on the exhaust tip to see visually if it's running rich, but i know it is for obvious reasons that i have observed and from other experience i have had with this issue, not only on my car, but friends cars as well.

I got the injectors anyways, since this was just too hard of a question and just too much tampering, so I got annoyed and just picked them up. I said I had a 3.0 regulator because I figured it may help in the determining some figures, but obviously it did not. But now I am confused as to why you think a lower 2.5(isnt this what they all come with, or used to?) or 2.7 bar reg would be better to have than a 3.0bar reg? I can't understand why....

anyways, I know you are trying to help, but don't try to be too nice....it was just a simple question that maybe someone knew, but I don't have a clue how this got so complicated. I did not want to go into detail because i know this was just a question that someone could have simply answered. But regardless, all this is done for now, i have gotten all the figures i need from another post....
 
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