FI Discussion Thread for the Boost Atheists
12-16-2007, 05:17 PM
#1
FI Discussion Thread for the Boost Atheists
You asked for it. You got it.
Since the other FI threads are either for dead product, defective product or aimed at one particular issue or another, let this be a place to talk about the semi-on-topic stuff that clogs those threads.
The topics du jour have been:
1) MAF range/tubing size
2) Idle bleeds
3) JAB/OMP bleed
etc.
Since the other FI threads are either for dead product, defective product or aimed at one particular issue or another, let this be a place to talk about the semi-on-topic stuff that clogs those threads.
The topics du jour have been:
1) MAF range/tubing size
2) Idle bleeds
3) JAB/OMP bleed
etc.
Last edited by MazdaManiac; 04-18-2008 at 05:24 PM. Reason: ©® 2008 MazdaManiac
12-16-2007, 05:29 PM
#2
The Professor
wouldn't it just be easier to create a thread for each of those topics and then link them all back to one "FI miscellaneous" thread page?
trying to throw a bunch of topics in one giant thread is just going to make searching that much harder than having clearly titled threads devoted to specific topics.
trying to throw a bunch of topics in one giant thread is just going to make searching that much harder than having clearly titled threads devoted to specific topics.
Last edited by staticlag; 12-16-2007 at 05:35 PM.
12-16-2007, 06:52 PM
#3
wouldn't it just be easier to create a thread for each of those topics and then link them all back to one "FI miscellaneous" thread page?
trying to throw a bunch of topics in one giant thread is just going to make searching that much harder than having clearly titled threads devoted to specific topics.
trying to throw a bunch of topics in one giant thread is just going to make searching that much harder than having clearly titled threads devoted to specific topics.
This thread is to tie them all together to practical applications.
We have 1/2 dozen or so FI options on the market that all have to deal with these issues.
This thread is where we put them to the test.
12-16-2007, 07:21 PM
#6
Finally Boosted!!!!!!!
The OEM MAF sensor has a voltage range of 0-5 volts and is mounted in a 3-3/8" id tube. When mounted in a pull-through setup it is estimated to reach it's maximum 5 volt reading at around 47 lbs/min of airflow.
12-16-2007, 07:50 PM
#8
With the flash recalibration you are using (and the idle air bleed that is associated with it), you will probably be good out to 450 or more since a fair amount of air is diverted around the MAF in the Pettit system.
12-16-2007, 08:42 PM
#9
a question from a beginner. The mop line. I was advised by someone much more knowledgeable than I to place a check valve on it also. Seems like the seals at times in the nozzles themselves are not up to snuf and on FI can actually bleed backward? i hope i am explaining that correctly. It was said that actual air bubbles in the mop could be seen going the wrong way. That means no oil available for injection?
Theory?
oldscdragger
Theory?
oldscdragger
12-16-2007, 08:43 PM
#10
Quick question...never really thought about this...and just so I don't clutter up the train of thought...
The voltage seen by the PCM is what is important correct? Based on the voltage and the ID of the tube (obviously being calibrated) you then determine the amount of air?
Correct?
The voltage seen by the PCM is what is important correct? Based on the voltage and the ID of the tube (obviously being calibrated) you then determine the amount of air?
Correct?
12-16-2007, 08:44 PM
#11
Dongbag extrordinare
Join Date: Nov 2004
Location: Away from the fruits of my labor
Posts: 1,090
Likes: 0
Received 0 Likes
on
0 Posts
Would it be allright if I took some pictures of my setup (particularly the routing of hoses) and asked some "newbie" technical questions?? I've been running F/I for @4k now and am still not completely sure about which hose does what, or purpose that is served.
If this thread isn't the place for that, could someone direct me to the right location??
If this thread isn't the place for that, could someone direct me to the right location??
12-16-2007, 08:46 PM
#12
Would it be allright if I took some pictures of my setup (particularly the routing of hoses) and asked some "newbie" technical questions?? I've been running F/I for @4k now and am still not completely sure about which hose does what, or purpose that is served.
If this thread isn't the place for that, could someone direct me to the right location??
If this thread isn't the place for that, could someone direct me to the right location??
Don't worry ppl will respond...
12-16-2007, 08:54 PM
#14
The mop line. I was advised by someone much more knowledgeable than I to place a check valve on it also. Seems like the seals at times in the nozzles themselves are not up to snuf and on FI can actually bleed backward? i hope i am explaining that correctly. It was said that actual air bubbles in the mop could be seen going the wrong way. That means no oil available for injection?
Quick question...never really thought about this...and just so I don't clutter up the train of thought...
The voltage seen by the PCM is what is important correct? Based on the voltage and the ID of the tube (obviously being calibrated) you then determine the amount of air?
Correct?
The voltage seen by the PCM is what is important correct? Based on the voltage and the ID of the tube (obviously being calibrated) you then determine the amount of air?
Correct?
By scaling the tube up in size, you increase the amount of air that would be needed to make the same reading.
Scaling the tube down would decrease the amount of air needed for that voltage.
Scaling the tube has other consequences - such as accuracy of the sensor and sensitivity.
Would it be allright if I took some pictures of my setup (particularly the routing of hoses) and asked some "newbie" technical questions?? I've been running F/I for @4k now and am still not completely sure about which hose does what, or purpose that is served.
If this thread isn't the place for that, could someone direct me to the right location??
If this thread isn't the place for that, could someone direct me to the right location??
If you do it in the Pettit threads, I'll get excoriated for trying to answer them.
12-16-2007, 08:55 PM
#15
12-16-2007, 08:59 PM
#16
Yes there is another oem check valve on the uim. If it was me i would purchase a better ones.
The maf voltage is only important if you are using it to run the engine? Those of us with the Int X really dont need the maf to run just the engine--correct?
It would be interesting as how the maf toward traction control etc is reacting when the int x is used and a smaller than oem intake is applied.
What are suggestions/theories out there about the vacuum hoses and a drawn through system?
thought on the VDI also?
oscd
i
The maf voltage is only important if you are using it to run the engine? Those of us with the Int X really dont need the maf to run just the engine--correct?
It would be interesting as how the maf toward traction control etc is reacting when the int x is used and a smaller than oem intake is applied.
What are suggestions/theories out there about the vacuum hoses and a drawn through system?
thought on the VDI also?
oscd
i
12-16-2007, 08:59 PM
#17
Yes. The MAF will determine the amount of actual airflow based on the voltage when passing the air through the OE tube.
By scaling the tube up in size, you increase the amount of air that would be needed to make the same reading.
Scaling the tube down would decrease the amount of air needed for that voltage.
Scaling the tube has other consequences - such as accuracy of the sensor and sensitivity.
By scaling the tube up in size, you increase the amount of air that would be needed to make the same reading.
Scaling the tube down would decrease the amount of air needed for that voltage.
Scaling the tube has other consequences - such as accuracy of the sensor and sensitivity.
outside of the complications...
could you not run a dual tube/maf solution and simply take the combined readings?
dual smaller tubes would keep the accuracy and still increase the capacity...
12-16-2007, 09:04 PM
#19
"MuNcH-E"
Join Date: Apr 2007
Location: Pembroke Pines
Posts: 627
Likes: 0
Received 0 Likes
on
0 Posts
I like this thread.
Thanks Ray and Jeff it all makes more sense to me know.
Basically with the right tune I should be able to go with a smaller pulley for more boost and still be in a safe range for the MAF to be working properly.
Thanks Ray and Jeff it all makes more sense to me know.
Basically with the right tune I should be able to go with a smaller pulley for more boost and still be in a safe range for the MAF to be working properly.
12-16-2007, 09:17 PM
#20
Finally Boosted!!!!!!!
You should still be in a safe range for the MAF but you need to make sure and keep your air temps in check. That may/may not be possible with the intercooler that ships with the kit.
12-16-2007, 09:19 PM
#21
The maf voltage is only important if you are using it to run the engine? Those of us with the Int X really dont need the maf to run just the engine--correct?
It would be interesting as how the maf toward traction control etc is reacting when the int x is used and a smaller than oem intake is applied.
It would be interesting as how the maf toward traction control etc is reacting when the int x is used and a smaller than oem intake is applied.
Early adopters of the Pettit systems lost their traction control and their auto trans shift authority because the MAF was excluded from the installation.
I don't know how accurate those numbers need to be for those systems, but seeing as how closely calibrated everything else on the RX-8 is, I can't help but think there is some functionality being lost by having the MAF show bad/inaccurate numbers.
Most of the vacuum driven accessories on the '8 are attached to check valves and vacuum reservoirs, so where they get their signal from isn't too important, as long as they get vacuum often enough to function.
The VDI and SSV require vacuum to drive their actuators, but they can be opened and closed a bunch of times on the vacuum held in the reservoir, so unless you are only driving in boost (wouldn't that be fun) you will "recharge" those accessories pretty regularly.
You can mask that with meth, but that is a very dangerous (and pointless) game.
12-16-2007, 09:20 PM
#22
Twink, you say "outside of the complications" and then present a hypothetical that is a complication, IMO, on top of what we have going now. If we discover that we can, in fact, use the current MAF in pass-through(?) systems up to 400-450 h.p. with the factory-sized duct then we can be reasonably assured that our idle managment will be as smooth as stock. If we increase the size of the intake tube then we will be discovering, at some point, just how low of a velocity air can travel through that tube and still be properly metered by the sensor.
12-16-2007, 09:22 PM
#23
EDIT:
In a FI application, what is the relation when it comes to the distance between the filter's location and the turbo itself...
12-16-2007, 09:26 PM
#25
The air in an FI system is moving at hundreds of feet per second.
That is why I laugh when people talk about "lag" caused by the intercooler plumbing being too long.
Its about volume, not length.