NEW DYNO RESULTS - UPDATE as of today 01/23/03
02-07-2003, 08:01 AM
#72
Senior Member
Join Date: May 2001
Posts: 1,305
Likes: 0
Received 0 Likes
on
0 Posts
ok i was thinking u meant physically breaking...
yea ur basically ****ed as far getting around the maf... unless u built some sort of secondary sensor or something 2 control a piggy back and 5th injector... but that sux for tuning, and the fact that the ecu has no idea what 2do with more current.... maybe u could flash the ecu 2 deal with the new Maf signal?
yea ur basically ****ed as far getting around the maf... unless u built some sort of secondary sensor or something 2 control a piggy back and 5th injector... but that sux for tuning, and the fact that the ecu has no idea what 2do with more current.... maybe u could flash the ecu 2 deal with the new Maf signal?
02-07-2003, 08:33 AM
#73
Senior Member
Join Date: May 2001
Posts: 1,436
Likes: 0
Received 0 Likes
on
0 Posts
Trust me, we've got a workable solution that's being tested as I type this smile.gif A few parts donations from my spare parts bin, some wiring on Bat's side and a handful of dyno re-tuning should likely get him back out in the world without the 250hp limit (next step would likely be somewhere around 400WHP, but ehh, I think his injectors and pistons will have quit by then)
I do belive we can do this while still being on stock ECU and not needing any additional piggyback equipment aside the stuff he already has. (Static fuel pressure regulator, stock MAF sensor, S-AFC, 440cc injectors, etc)
I do belive we can do this while still being on stock ECU and not needing any additional piggyback equipment aside the stuff he already has. (Static fuel pressure regulator, stock MAF sensor, S-AFC, 440cc injectors, etc)
02-07-2003, 08:55 AM
#74
Senior Member
Join Date: Aug 2001
Posts: 1,290
Likes: 0
Received 0 Likes
on
0 Posts
Bat!
Did you end up getting my email regarding teh 1.8L ECU?
You should install it into your Tibby and defently will run more richer tahn the 2.0L ECU!
Let me know smile.gif smile.gif
Did you end up getting my email regarding teh 1.8L ECU?
You should install it into your Tibby and defently will run more richer tahn the 2.0L ECU!
Let me know smile.gif smile.gif
02-07-2003, 09:33 AM
#75
Senior Member
Join Date: May 2001
Posts: 1,436
Likes: 0
Received 0 Likes
on
0 Posts
Richer doesn't matter, because it will still suddenly stop when the MAF hits it's maximum flow limit... The 1.8L ECU has every reason to be a BIGGER problem in Bat's case than the 2.0L ECU because the fuel mapping tables were designed for a smaller motor on the same MAF sensor.
If the MAF is maxing out, no amount of ECU fixes is going to make it better.
If the MAF is maxing out, no amount of ECU fixes is going to make it better.
02-07-2003, 02:19 PM
#76
Senior Member
Join Date: Jul 2002
Posts: 135
Likes: 0
Received 0 Likes
on
0 Posts
but red, with CNK's piggyback ecu, it is set up for MAP and you replace the MAF in the car with a MAP sensor. so this wouldn't be clamping the signal, right? as far as my understanding, i would assume that the MAP sensor wires into the piggyback which translates it to the stock ecu for fuel demand. i'll ask chris just to be sure, but you made it sound like (i guess the alpine does this) its trying to get around the maf, when it's replacing it.
02-09-2003, 12:39 AM
#77
Senior Member
Join Date: May 2001
Posts: 1,436
Likes: 0
Received 0 Likes
on
0 Posts
If you're on the stock ECU, there's no method I know of ANYWHERE to convert a MAP signal to anything useful by a MAF system. They measure two entirely different things, and there isn't any accurate way to translate between the two.
MAF is completely dependant on airflow and nothing else. Air is half of what makes the car run, and the MAF measures the airflow directly.
MAP is completely dependant on pressure, and nothing else. Air is STILL what makes the car work, but the MAP sensor is unable to see air flow. Thus, the programming on the computer must be RADICALLY different because you must always assume the motor is always volumetrically stock in order for a MAP-based computer system to correctly manipulate fuel.
You can't just rip the MAF sensor off and replace it with a MAP, unless you're ripping the entire stock ECU out and fully replacing it. There is no other alternative...
MAF is completely dependant on airflow and nothing else. Air is half of what makes the car run, and the MAF measures the airflow directly.
MAP is completely dependant on pressure, and nothing else. Air is STILL what makes the car work, but the MAP sensor is unable to see air flow. Thus, the programming on the computer must be RADICALLY different because you must always assume the motor is always volumetrically stock in order for a MAP-based computer system to correctly manipulate fuel.
You can't just rip the MAF sensor off and replace it with a MAP, unless you're ripping the entire stock ECU out and fully replacing it. There is no other alternative...
02-09-2003, 02:34 AM
#79
Senior Member
Join Date: May 2001
Posts: 1,436
Likes: 0
Received 0 Likes
on
0 Posts
You are suggesting that an FMU be bolted to the car and set for higher fuel pressure, but also have it hooked up so that it only starts raising fuel pressure after the manifold (air) pressure reaches a certain boost level. So for example, at 10psi the little "switch" kicks in and the FMU starts in...
There are two nasty problems with your solution; both require that you fully understand how FMU's work.
FMU's are one of two types: static or rising rate. A static FMU is one where you set the pressure (say 65psi) and it STAYS at 65psi no matter what. Doesn't matter if you're at 20 inches of vacuum or 30 pounds of boost, the static FMU is 65psi. Rising rate FMU's raise fuel pressure by a fractional amount based on the boost your engine is eating. A 2:1 FMU would raise fuel pressure 2psi for every 1psi of manifold pressure.
Thus, your idea would never work with a "static" FMU. You cannot turn it off or on based on manifold pressure; fuel is ALWAYS going through it. This limits your option to a rising rate FMU, which would only affect fuel pressure if you're feeding it boost.
In this sceneario, here are your two problems:
#1. HUGE surge of fuel pressure at the predetermined switch point. Your FMU is sitting there minding it's own business, when suddenly (when your switch happens) it's seeing 10 pounds of boost. It instantly kicks your fuel pressure into the stratosphere; a 6:1 rate would slam another 60psi into your fuel rail. So as you're accelerating and your motor is building more boost, right when your boost needle swings past the magic 10psi mark (or whatever your setting is), the car suddenly drowns in fuel.
Ok, so why not use just a smaller rate on the FMU? That leads to the next problem...
#2. Feeding more boost by ONLY increasing fuel pressure requires a LOT of fuel pressure. If you want to run another single pound of boost, you're going to need somewhere between six and twelve more pounds of fuel pressure. Thus, you are going to need a very high ramp rate on your FMU to make sure that, after the MAF has stopped responding, you can continue to feed the engine enough gasoline to not burn it up.
So, you have to keep high pressure IF that's all you're relying on to feed the car after the MAF dies, but you cannot just "switch on" the pressure because it needs to ramp smoothly from AFTER the point that the MAF dies.
If the MAF dies at 10psi, then you need to ramp fuel pressure basically at an 8:1 ratio STARTING with 10psi on the manifold. I don't know if you understand what I'm saying, but a rising rate FMU will just perform simple multiplaction: You switch it "on" with your trick, it sees 10psi on the manifold, it will suddenly send 80psi more fuel.
What you NEED it to do is have it see 10psi on the manifold, and send ZERO more fuel pressure BUT you need it to start raising 8psi of fuel for every 1psi of manifold pressure after 10psi.
No such part exists anywhere in the world.
There are two nasty problems with your solution; both require that you fully understand how FMU's work.
FMU's are one of two types: static or rising rate. A static FMU is one where you set the pressure (say 65psi) and it STAYS at 65psi no matter what. Doesn't matter if you're at 20 inches of vacuum or 30 pounds of boost, the static FMU is 65psi. Rising rate FMU's raise fuel pressure by a fractional amount based on the boost your engine is eating. A 2:1 FMU would raise fuel pressure 2psi for every 1psi of manifold pressure.
Thus, your idea would never work with a "static" FMU. You cannot turn it off or on based on manifold pressure; fuel is ALWAYS going through it. This limits your option to a rising rate FMU, which would only affect fuel pressure if you're feeding it boost.
In this sceneario, here are your two problems:
#1. HUGE surge of fuel pressure at the predetermined switch point. Your FMU is sitting there minding it's own business, when suddenly (when your switch happens) it's seeing 10 pounds of boost. It instantly kicks your fuel pressure into the stratosphere; a 6:1 rate would slam another 60psi into your fuel rail. So as you're accelerating and your motor is building more boost, right when your boost needle swings past the magic 10psi mark (or whatever your setting is), the car suddenly drowns in fuel.
Ok, so why not use just a smaller rate on the FMU? That leads to the next problem...
#2. Feeding more boost by ONLY increasing fuel pressure requires a LOT of fuel pressure. If you want to run another single pound of boost, you're going to need somewhere between six and twelve more pounds of fuel pressure. Thus, you are going to need a very high ramp rate on your FMU to make sure that, after the MAF has stopped responding, you can continue to feed the engine enough gasoline to not burn it up.
So, you have to keep high pressure IF that's all you're relying on to feed the car after the MAF dies, but you cannot just "switch on" the pressure because it needs to ramp smoothly from AFTER the point that the MAF dies.
If the MAF dies at 10psi, then you need to ramp fuel pressure basically at an 8:1 ratio STARTING with 10psi on the manifold. I don't know if you understand what I'm saying, but a rising rate FMU will just perform simple multiplaction: You switch it "on" with your trick, it sees 10psi on the manifold, it will suddenly send 80psi more fuel.
What you NEED it to do is have it see 10psi on the manifold, and send ZERO more fuel pressure BUT you need it to start raising 8psi of fuel for every 1psi of manifold pressure after 10psi.
No such part exists anywhere in the world.
02-09-2003, 03:52 AM
#80
Senior Member
Join Date: May 2001
Posts: 1,305
Likes: 0
Received 0 Likes
on
0 Posts
well tehnically u could have a solienoid hookedup 2 a boost guage that would read the 10psi and then u could have a restrictor that could control the amount of positive pressure that the FMU sees...
well **** now that i think of it that doest make much sense
what we really need is some sort of electronically controlled FMU which will see booost and know when to tell the FMU to send more fuel
this could easiy be done with a computer controlled regulator,they arlready do it with gas on the angel air system for paintball so im sure it wouldnt be 2 hard to do it for liquid
well **** now that i think of it that doest make much sense
what we really need is some sort of electronically controlled FMU which will see booost and know when to tell the FMU to send more fuel
this could easiy be done with a computer controlled regulator,they arlready do it with gas on the angel air system for paintball so im sure it wouldnt be 2 hard to do it for liquid