My concerns about FMU settings w/ the Procharger
09-06-2003, 11:28 PM
#1
Registered User
Thread Starter
Join Date: Feb 2003
Posts: 1,962
Likes: 0
Received 0 Likes
on
0 Posts
My concerns about FMU settings w/ the Procharger
Okay......i've been biting my tongue about this for a while now, but i can't keep silent anymore..........this is my concern.........so far there have been 3 supercharged Z's that have experienced engine problems......2 serious problems, and one undiagnosed so far.
Per the Aeromotive manual, the scale setting on it should be the same as the maximum boost level.......so the little yellow dial should be at 7 or 8, since this is a 7 psi kit
The disturbing thing is that every FMU i've ever seen, or heard about on this forum has been set at 10 or above.......and frankly, i see this as a ticking time bomb
I don't care if i get flamed for speaking out about this, but i really don't want to see any more engines get damaged
To qualify my statements........i've been running UNTUNED for 1750 miles with no problems,and my scale setting is on 8..........my exhaust is stinky, but my engine is doing well
Flame away
Per the Aeromotive manual, the scale setting on it should be the same as the maximum boost level.......so the little yellow dial should be at 7 or 8, since this is a 7 psi kit
The disturbing thing is that every FMU i've ever seen, or heard about on this forum has been set at 10 or above.......and frankly, i see this as a ticking time bomb
I don't care if i get flamed for speaking out about this, but i really don't want to see any more engines get damaged
To qualify my statements........i've been running UNTUNED for 1750 miles with no problems,and my scale setting is on 8..........my exhaust is stinky, but my engine is doing well
Flame away
09-07-2003, 12:18 AM
#3
Banned
Join Date: May 2002
Location: Smackahoe Blvd
Posts: 13,063
Likes: 0
Received 0 Likes
on
0 Posts
Basically, the tuners are setting the car too lean, is that what you are saying? If that is the case.........KABOOM!!!
In any FI application, proper fueling is the most important thing. The worst thing that will happen from running rich is that you will foul your plugs, but run too lean for an instant and it's all over. People keep saying it's the compression, but that is totally untrue. There are plenty of supercharged Stooks running around with little or no problems.
The second most important thing is controlling detonation. As long as you can control your mixture and detonation, I think you could run 14lbs of boost with little problem.
In any FI application, proper fueling is the most important thing. The worst thing that will happen from running rich is that you will foul your plugs, but run too lean for an instant and it's all over. People keep saying it's the compression, but that is totally untrue. There are plenty of supercharged Stooks running around with little or no problems.
The second most important thing is controlling detonation. As long as you can control your mixture and detonation, I think you could run 14lbs of boost with little problem.
Trending Topics
09-07-2003, 07:01 AM
#8
Sponsor
Sport Z Magazine
Sport Z Magazine
It seems to me it is worth it to ATI to jump in here and make a broad statement about what is the range that is acceptable for the settings. Just have an air intake or tuned ehaust cannot change the settings that radically. Our Z's cannot be that much different in their settings.
I know with each Z that has a problem, the less likely I am to buy an ATI SC. This is sad for me to say because I really want that unit but how can I buy one with contined problems showing up?
The company ATI has a lot to loss by just sitting and watching our motors blow up. Thry have got enginers. If I were them, I would have flown one down to investigate each problem car. In the long run, they would fix the problems, get our respect, and increase sales.
Something is wrong. Cars like the JIC car have something like 5K on it with no problem yet others blow at 300 miles.
I know with each Z that has a problem, the less likely I am to buy an ATI SC. This is sad for me to say because I really want that unit but how can I buy one with contined problems showing up?
The company ATI has a lot to loss by just sitting and watching our motors blow up. Thry have got enginers. If I were them, I would have flown one down to investigate each problem car. In the long run, they would fix the problems, get our respect, and increase sales.
Something is wrong. Cars like the JIC car have something like 5K on it with no problem yet others blow at 300 miles.
Last edited by zland; 09-07-2003 at 07:05 AM.
09-07-2003, 07:19 AM
#9
New Member
Join Date: Apr 2003
Location: Earth
Posts: 5,563
Likes: 0
Received 0 Likes
on
0 Posts
The only thing that can account for these types of things is what the FMU is seeing for boost from the intake manifold.
Either people's SC/intercooler/intake piping is leaking from poor connections and untightened clamps or the output from the intake manifold is leaking. In my "check these things if you've got a procharger thread" I explain exactly how to check for the intake manifold output leaks in #6.
If you do discover leaks, and then fix them, you WILL need to get your car tuned again, until then disconnect a cog belt so your SC won't spin.
Either people's SC/intercooler/intake piping is leaking from poor connections and untightened clamps or the output from the intake manifold is leaking. In my "check these things if you've got a procharger thread" I explain exactly how to check for the intake manifold output leaks in #6.
If you do discover leaks, and then fix them, you WILL need to get your car tuned again, until then disconnect a cog belt so your SC won't spin.
Last edited by jesseenglish; 09-07-2003 at 07:21 AM.
09-07-2003, 11:19 AM
#11
Sure dude.. go ahead and run 14psi on the VQ stock motor... even with ecu timing retardation and fuel...you can see yourself what "little problem" you'll actually be seeing..
Originally posted by raceboy
The second most important thing is controlling detonation. As long as you can control your mixture and detonation, I think you could run 14lbs of boost with little problem.
The second most important thing is controlling detonation. As long as you can control your mixture and detonation, I think you could run 14lbs of boost with little problem.
09-07-2003, 01:13 PM
#13
Registered User
Thread Starter
Join Date: Feb 2003
Posts: 1,962
Likes: 0
Received 0 Likes
on
0 Posts
Guys, it's not the sliders that are the critical thing here.......it's the little yellow pointer.......for example.......DrBonz's scale setting is at 15.........this means his FMU is looking for a total of 15 pounds of boost........since he's only running 7 pounds of boost, he's only using the first 3 slider's!!!!!
This is what i'm talking about........whatever that pointer is set at will be divided equally among the sliders.......in Bonz's case each slider is worth 3 pounds of boost.......you can see how this can be a problem.......he has the SAME fuel setting for 1-3 pounds of boost.....and the SAME setting for 4-6 pounds of boost.....then when he gets to 7psi it jumps into the third slider, but never gets above the third slider!
This is what i'm talking about........whatever that pointer is set at will be divided equally among the sliders.......in Bonz's case each slider is worth 3 pounds of boost.......you can see how this can be a problem.......he has the SAME fuel setting for 1-3 pounds of boost.....and the SAME setting for 4-6 pounds of boost.....then when he gets to 7psi it jumps into the third slider, but never gets above the third slider!
Last edited by elektrik_juggernaut; 09-07-2003 at 01:39 PM.
09-07-2003, 05:42 PM
#15
New Member
Join Date: Apr 2003
Location: Earth
Posts: 5,563
Likes: 0
Received 0 Likes
on
0 Posts
EJ,
I understand where you're coming from on this, and theoretically that is how it should work, but my experiences tell a different story.
My scale setting is at 11 and I see the 5th light light up if I run it up to 5000RPM. That would mean I had 8.8 pounds of boost at 5000 RPM if your explanation was true. When I know for a fact that the tuner was only reading 5.8 pounds of boost.
I understand where you're coming from on this, and theoretically that is how it should work, but my experiences tell a different story.
My scale setting is at 11 and I see the 5th light light up if I run it up to 5000RPM. That would mean I had 8.8 pounds of boost at 5000 RPM if your explanation was true. When I know for a fact that the tuner was only reading 5.8 pounds of boost.
09-07-2003, 05:53 PM
#16
Registered User
Thread Starter
Join Date: Feb 2003
Posts: 1,962
Likes: 0
Received 0 Likes
on
0 Posts
But if these FMU's aren't functioning as they should, then we have an even bigger problem.....something as critical as this component NEEDS to be accurate or we're all entirely screwed........and at 400 bucks a pop, this thing should be working exactly the way it's supposed to
I realize i'm yelling "fire" in a crowded theater, but maybe there really is a fire here.........i just don't wanna see any more engines blow
I realize i'm yelling "fire" in a crowded theater, but maybe there really is a fire here.........i just don't wanna see any more engines blow
09-07-2003, 05:56 PM
#17
The scale setting needs to be set so that the last band is entered at about 5.5 psi. I set mine using a metered air supply to achieve this, and I have verified that mine gets into the last band somewhere approaching redline. My scale setting ended up at about 13. I tried setting the scale to 5.5 and to 7, and in each case the fmu went through the bands too quickly, such that it had already entered the last band somewhere around 3 psi.
This scale setting is something that should be set individually on every car, the same goes for the slide adjustments. I think most should end up at the same approximate scale setting, but there will still be some variation. This whole fmu setting ordeal is not something that can be guessed at. If you want the car to run properly and safely, you have to tune the car using a wideband o2 sensor.
I don't know why the scale setting is not ending up anywhere close to what the Aeromotive manual says. Maybe there is something different about the ones supplied to ATI for use in their kit. I do know that ATI presets the fmu with their recommended starting points for both the sliders and the scale adjustment. Mine was set at 13 when I received it, and after playing with it I ended up right back at where it started. All bands are used properly at this setting, verified by driving and by using a calibrated pressure gauge to test the fuel system and fmu.
This scale setting is something that should be set individually on every car, the same goes for the slide adjustments. I think most should end up at the same approximate scale setting, but there will still be some variation. This whole fmu setting ordeal is not something that can be guessed at. If you want the car to run properly and safely, you have to tune the car using a wideband o2 sensor.
I don't know why the scale setting is not ending up anywhere close to what the Aeromotive manual says. Maybe there is something different about the ones supplied to ATI for use in their kit. I do know that ATI presets the fmu with their recommended starting points for both the sliders and the scale adjustment. Mine was set at 13 when I received it, and after playing with it I ended up right back at where it started. All bands are used properly at this setting, verified by driving and by using a calibrated pressure gauge to test the fuel system and fmu.
09-07-2003, 06:37 PM
#18
New Member
Join Date: Apr 2003
Location: Earth
Posts: 5,563
Likes: 0
Received 0 Likes
on
0 Posts
Originally posted by GaryK
This scale setting is something that should be set individually on every car, the same goes for the slide adjustments. I think most should end up at the same approximate scale setting, but there will still be some variation. This whole fmu setting ordeal is not something that can be guessed at. If you want the car to run properly and safely, you have to tune the car using a wideband o2 sensor.
This scale setting is something that should be set individually on every car, the same goes for the slide adjustments. I think most should end up at the same approximate scale setting, but there will still be some variation. This whole fmu setting ordeal is not something that can be guessed at. If you want the car to run properly and safely, you have to tune the car using a wideband o2 sensor.
Only thing I want to add, and I've mentioned it before. Ensure that your tuner is knowledgeable with the Aeromotive FMU's operation and that he knows you don't want your max AFR leaner than 12:1
09-07-2003, 06:58 PM
#19
Registered User
Thread Starter
Join Date: Feb 2003
Posts: 1,962
Likes: 0
Received 0 Likes
on
0 Posts
IPT is at 8, Bonz is at 15, GaryK is at 13, and jesse is at 11......if these units are going to be trusted to handle the most important aspect of this kit, they should be operating the way they were supposed to.
09-07-2003, 07:05 PM
#20
New Member
Join Date: Apr 2003
Location: Earth
Posts: 5,563
Likes: 0
Received 0 Likes
on
0 Posts
I agree with you completely that they should be close and I will be sure to bring this up with Aeromotive and ATI when I call them tomorrow.
I still truely believe that most of the variation we're seeing is from installation irregularities and individual tuner preferences.
I still truely believe that most of the variation we're seeing is from installation irregularities and individual tuner preferences.