follow ft86club on our blog, twitter or facebook.
FT86CLUB
Ft86Club
86SPEED
Register Garage Members List Calendar Search Today's Posts Mark Forums Read

Go Back   Scion FR-S Forum | Subaru BRZ Forum | Toyota 86 GT 86 Forum | AS1 Forum - FT86CLUB > Technical Topics > Engine, Exhaust, Transmission

Engine, Exhaust, Transmission Discuss the FR-S | 86 | BRZ engine, exhaust and drivetrain.


User Tag List

Reply
 
Thread Tools Search this Thread
Old 06-22-2016, 04:51 PM   #29
nelsmar
Senior Member
 
Join Date: Feb 2013
Drives: FR-S
Location: Phoenix
Posts: 2,603
Thanks: 733
Thanked 2,353 Times in 1,030 Posts
Mentioned: 345 Post(s)
Tagged: 3 Thread(s)
So here is an idea.... How about you un-screw the MAF at idle. Lift it up while logging and see if the load value changes... If you lift the MAF out of the intake pipe your IAT temp may change which would possibly alter a speed density volumetric efficiency value slightly... but not crazy significantly... However removing the MAF from the intake pipe on a MAF tuned car will make a significant change and the car will struggle quite a bit.

Upping the fuel pressure is going to be a massive waste. There is a very high likeliness that less than 20% of your fueling after 3,200RPM is from the port injectors. So if you are running 13.5AFR and trying to get to 12.5 which is 8% more fueling and you are running 20% fueling from port with 4 bar fuel pressure you are going to need something closer to 7-8 bar of fueling to hit that target. And thats if it is actually 20% fueling... The factory tune in the low end actually uses pure DI until iirc 5000RPM or 1.5 load value.

If the motec tune has anything similar to the OEM setup it will be the same. And I'm going to guess that since they were caring more about performance than economy they were not going to use the port injection very much. As you don't have enough engine load to justify a port injection to shorten the direct injection time to improve quality of fuel mixture. You are realistically probably 5-10% port injection after 4,500RPM or so. And since the DI system has its own pressure sensor it can compensate. The DI pump is simply going to stop increasing the fuel pressure once it hits a certain point and nothing will happen.

More importantly where is the o2 sensor that you used to determine 13.5:1? If it was in the tail pipe and you had an exhaust leak and a large exhaust tip it is easily acceptable to consider the 13.5:1 being an inaccurate reading. You should place the o2 closer to the engine to verify you have a good reading. Or maybe try reading with the motec unit.
__________________
When I grow up, I wanna be God.
My flickr - Canibeat
Local magazine scout
Old Setup: Vortech Supercharged 360WHP/262WTQ @ 11.5psi
My build thread - WTF happened to nelsmar's car thread
nelsmar is offline   Reply With Quote
Old 06-22-2016, 05:25 PM   #30
Crunk81us
Member
 
Join Date: May 2016
Drives: Toyota 86
Location: Australia
Posts: 39
Thanks: 8
Thanked 4 Times in 4 Posts
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quote:
Originally Posted by nelsmar View Post
So here is an idea.... How about you un-screw the MAF at idle. Lift it up while logging and see if the load value changes... If you lift the MAF out of the intake pipe your IAT temp may change which would possibly alter a speed density volumetric efficiency value slightly... but not crazy significantly... However removing the MAF from the intake pipe on a MAF tuned car will make a significant change and the car will struggle quite a bit.

Upping the fuel pressure is going to be a massive waste. There is a very high likeliness that less than 20% of your fueling after 3,200RPM is from the port injectors. So if you are running 13.5AFR and trying to get to 12.5 which is 8% more fueling and you are running 20% fueling from port with 4 bar fuel pressure you are going to need something closer to 7-8 bar of fueling to hit that target. And thats if it is actually 20% fueling... The factory tune in the low end actually uses pure DI until iirc 5000RPM or 1.5 load value.

If the motec tune has anything similar to the OEM setup it will be the same. And I'm going to guess that since they were caring more about performance than economy they were not going to use the port injection very much. As you don't have enough engine load to justify a port injection to shorten the direct injection time to improve quality of fuel mixture. You are realistically probably 5-10% port injection after 4,500RPM or so. And since the DI system has its own pressure sensor it can compensate. The DI pump is simply going to stop increasing the fuel pressure once it hits a certain point and nothing will happen.

More importantly where is the o2 sensor that you used to determine 13.5:1? If it was in the tail pipe and you had an exhaust leak and a large exhaust tip it is easily acceptable to consider the 13.5:1 being an inaccurate reading. You should place the o2 closer to the engine to verify you have a good reading. Or maybe try reading with the motec unit.
Its purely di, the pi is not used at all. never.

they didnt care so much about performance as opposed to longevity (toyota didnt want any cars blowing up on tv.. bad press)

you are right in assuming it was in the tailpipe, I will be doing it from the o2 sensor next session. though i do not think it was far off the mark as many others have tested with similar results.
Crunk81us is offline   Reply With Quote
Old 06-22-2016, 05:36 PM   #31
nelsmar
Senior Member
 
Join Date: Feb 2013
Drives: FR-S
Location: Phoenix
Posts: 2,603
Thanks: 733
Thanked 2,353 Times in 1,030 Posts
Mentioned: 345 Post(s)
Tagged: 3 Thread(s)
Quote:
Originally Posted by Crunk81us View Post
Its purely di, the pi is not used at all. never.

they didnt care so much about performance as opposed to longevity (toyota didnt want any cars blowing up on tv.. bad press)

you are right in assuming it was in the tailpipe, I will be doing it from the o2 sensor next session. though i do not think it was far off the mark as many others have tested with similar results.
If it is in fact 100% DI then raising your fuel pressure is going to do absolutely nothing unless you magically have a fuel source that is above 20MPa (200bar). Considering the DI pump pressurizes the system to ~20MPa in factory form for most of the power band.

As for the PI, it is mostly used to clean the top of the valves and improve longevity of the engine. Although it is used to help under heavy load to give a better burn quality when the DI injection time is too long and doesn't give an even distribution of fuel.

So for your case I would start with finding out if it is speed density or if it is a mass air flow based tune. This is simple to test and can be done without breaking any laws in your region since you can do it by simply idling the car and removing the sensor (leave it plugged in at first, and maybe even unplug it while logging to see what happens).

My wideband can swing 0.5-1.5 AFR on massive tipped exhausts with low volume of air flowing through. The dyno I used to use would be consistently 0.5-1AFR leaner than actual when using the tail pipe. But that unit was having a slight calibration issue and no one ever cared to fix it.

You should have a rear o2 sensor bung on your manifold that you could use for testing the actual AFR. It is however best to test this pre-cat. So it might be worth doing a pull with the primary o2 removed, or simply moved post cat if you still have a cat in the header. I don't know a ton about your scenario and just took a few moments to search around on other posts... Is there a certain baseline you should be expecting? If you were to put the factory computer in and do a pull without any learning the car will likely show more power due to the car running extra lean, or overly advanced due to no learning. It takes a bit of driving for the learning to kick in. Comparing your power to another dyno using the same ecu would not be very rational. You would need another car on that same dyno to get an "idea" of what to expect. But I am going to guess that moving the o2 sensor you may see a good 0.5 AFR richer (though this might not happen) and get you closer to what you should be seeing.
__________________
When I grow up, I wanna be God.
My flickr - Canibeat
Local magazine scout
Old Setup: Vortech Supercharged 360WHP/262WTQ @ 11.5psi
My build thread - WTF happened to nelsmar's car thread
nelsmar is offline   Reply With Quote
The Following User Says Thank You to nelsmar For This Useful Post:
justatroll (06-22-2016)
Old 06-22-2016, 05:48 PM   #32
justatroll
Senior Member
 
justatroll's Avatar
 
Join Date: Dec 2015
Drives: Full race 4cyl boxer
Location: CO, USA
Posts: 587
Thanks: 310
Thanked 508 Times in 269 Posts
Mentioned: 20 Post(s)
Tagged: 1 Thread(s)
Quote:
Originally Posted by nelsmar View Post
If it is in fact 100% DI then raising your fuel pressure is going to do absolutely nothing unless you magically have a fuel source that is above 20MPa (200bar). Considering the DI pump pressurizes the system to ~20MPa in factory form for most of the power band.
.
, great minds :-)

Quote:
Originally Posted by justatroll View Post
Stupid question BUT:

Since the engine runs mostly on DI, and the DI fuel pump is downstream of the electric fuel pump (and has its OWN control loop for duty cycle) - WHY does fuel pressure from the electric FP in any way affect the pressure to the DI system?
(assuming the HP is not soo big that the system is starving overall)
justatroll is offline   Reply With Quote
The Following User Says Thank You to justatroll For This Useful Post:
nelsmar (06-22-2016)
Old 06-22-2016, 06:17 PM   #33
Crunk81us
Member
 
Join Date: May 2016
Drives: Toyota 86
Location: Australia
Posts: 39
Thanks: 8
Thanked 4 Times in 4 Posts
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quote:
Originally Posted by nelsmar View Post
If it is in fact 100% DI then raising your fuel pressure is going to do absolutely nothing unless you magically have a fuel source that is above 20MPa (200bar). Considering the DI pump pressurizes the system to ~20MPa in factory form for most of the power band.

As for the PI, it is mostly used to clean the top of the valves and improve longevity of the engine. Although it is used to help under heavy load to give a better burn quality when the DI injection time is too long and doesn't give an even distribution of fuel.

So for your case I would start with finding out if it is speed density or if it is a mass air flow based tune. This is simple to test and can be done without breaking any laws in your region since you can do it by simply idling the car and removing the sensor (leave it plugged in at first, and maybe even unplug it while logging to see what happens).

My wideband can swing 0.5-1.5 AFR on massive tipped exhausts with low volume of air flowing through. The dyno I used to use would be consistently 0.5-1AFR leaner than actual when using the tail pipe. But that unit was having a slight calibration issue and no one ever cared to fix it.

You should have a rear o2 sensor bung on your manifold that you could use for testing the actual AFR. It is however best to test this pre-cat. So it might be worth doing a pull with the primary o2 removed, or simply moved post cat if you still have a cat in the header. I don't know a ton about your scenario and just took a few moments to search around on other posts... Is there a certain baseline you should be expecting? If you were to put the factory computer in and do a pull without any learning the car will likely show more power due to the car running extra lean, or overly advanced due to no learning. It takes a bit of driving for the learning to kick in. Comparing your power to another dyno using the same ecu would not be very rational. You would need another car on that same dyno to get an "idea" of what to expect. But I am going to guess that moving the o2 sensor you may see a good 0.5 AFR richer (though this might not happen) and get you closer to what you should be seeing.
I have no cat..

I know there wont be much effect on afr by raising the fuel pump pressure due to running di. But i have had mixed reports on it doing nothing at all or something. i will prove it on the dyno next time with a temporary bosch pump and fpr.

Will be testing from the o2 sensor hole this time.

doing a bunch of other things and back to back testing as well.

It's difficult to prove whether one car is making more than the others due to the distance between me and the majority of the other cars, plus I am fairly sure the cars at the front of the field wouldnt be putting their hands up for testing against the slow cars! What i can say is that I am not the only one who feels disadvantaged by lack of power, and there appears to be a BIG difference between the cars at the back of the pack and the front runners.

Like someone said to me once, if you dont cheat ur an idiot. If you get caught cheating you're a bigger idiot. I must be an idiot. lol
Crunk81us is offline   Reply With Quote
Old 06-22-2016, 06:30 PM   #34
nelsmar
Senior Member
 
Join Date: Feb 2013
Drives: FR-S
Location: Phoenix
Posts: 2,603
Thanks: 733
Thanked 2,353 Times in 1,030 Posts
Mentioned: 345 Post(s)
Tagged: 3 Thread(s)
Quote:
Originally Posted by Crunk81us View Post
I have no cat..

I know there wont be much effect on afr by raising the fuel pump pressure due to running di. But i have had mixed reports on it doing nothing at all or something. i will prove it on the dyno next time with a temporary bosch pump and fpr.

Will be testing from the o2 sensor hole this time.

doing a bunch of other things and back to back testing as well.

It's difficult to prove whether one car is making more than the others due to the distance between me and the majority of the other cars, plus I am fairly sure the cars at the front of the field wouldnt be putting their hands up for testing against the slow cars! What i can say is that I am not the only one who feels disadvantaged by lack of power, and there appears to be a BIG difference between the cars at the back of the pack and the front runners.

Like someone said to me once, if you dont cheat ur an idiot. If you get caught cheating you're a bigger idiot. I must be an idiot. lol
I can tell you it will do nothing. I speak from experience, not from internet engineering experience. The motec ecu knows the fuel pressure and the DI pump will change its duty cycle to lower the pressure. It is not based off the cam profile like you might be thinking. There is an actuator that can enable / disable the mechanical pump at a high rate to regulate the fuel pressure on the DI rails. You are more than welcome to do it on the dyno if you have one, however if you are paying to use one you are likely going to be disappointed with the money you spent to strap the car down. If adjusting the pressure made a difference you would see it even more significantly at idle since the OEM tune uses ~ 4MPa at idle. This is significantly lower than the 20MPa you are trying to compensate for. Im just going out of my way to try and help save you some time and effort =)

I have tuned cars with aftermarket regulators and return lines and there is no difference in the output of the AFR with altered fuel pressure. The only difference i the duty cycle will change slightly on the pump. And it has been tested before in attempt to raise that pressure even higher by phil @ evasive. You can only request the pump to go so high and it wont go any higher... I don't recall what pressure he managed to get it to but he did this by commanding a higher duty cycle... Considering it is in a closed loop function and you cannot modify this (closed loop meaning the ecu reads the current pressure... and when it changes it modifies the rate on its own) you will have poor luck modifying it. I would love for me to be wrong...

I can also tell you I have tried commanding 22MPa with the factory ecu and it doesn't go up any more than the standard 20MPa but this could also be related to OEM ecu logic having a maximum pressure allowance of 20MPa. Since I haven't disassembled the rom my self I cannot say for sure but considering how well it lines up the results im going to say its the ecu stopping it.
__________________
When I grow up, I wanna be God.
My flickr - Canibeat
Local magazine scout
Old Setup: Vortech Supercharged 360WHP/262WTQ @ 11.5psi
My build thread - WTF happened to nelsmar's car thread
nelsmar is offline   Reply With Quote
The Following User Says Thank You to nelsmar For This Useful Post:
Crunk81us (06-22-2016)
Old 06-22-2016, 06:30 PM   #35
nelsmar
Senior Member
 
Join Date: Feb 2013
Drives: FR-S
Location: Phoenix
Posts: 2,603
Thanks: 733
Thanked 2,353 Times in 1,030 Posts
Mentioned: 345 Post(s)
Tagged: 3 Thread(s)
Quote:
Originally Posted by justatroll View Post
, great minds :-)
Hah! I didn't even see your post. Your spot on =P
__________________
When I grow up, I wanna be God.
My flickr - Canibeat
Local magazine scout
Old Setup: Vortech Supercharged 360WHP/262WTQ @ 11.5psi
My build thread - WTF happened to nelsmar's car thread
nelsmar is offline   Reply With Quote
Old 06-22-2016, 06:50 PM   #36
Crunk81us
Member
 
Join Date: May 2016
Drives: Toyota 86
Location: Australia
Posts: 39
Thanks: 8
Thanked 4 Times in 4 Posts
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quote:
Originally Posted by nelsmar View Post
I can tell you it will do nothing. I speak from experience, not from internet engineering experience. The motec ecu knows the fuel pressure and the DI pump will change its duty cycle to lower the pressure. It is not based off the cam profile like you might be thinking. There is an actuator that can enable / disable the mechanical pump at a high rate to regulate the fuel pressure on the DI rails. You are more than welcome to do it on the dyno if you have one, however if you are paying to use one you are likely going to be disappointed with the money you spent to strap the car down. If adjusting the pressure made a difference you would see it even more significantly at idle since the OEM tune uses ~ 4MPa at idle. This is significantly lower than the 20MPa you are trying to compensate for. Im just going out of my way to try and help save you some time and effort =)

I have tuned cars with aftermarket regulators and return lines and there is no difference in the output of the AFR with altered fuel pressure. The only difference i the duty cycle will change slightly on the pump. And it has been tested before in attempt to raise that pressure even higher by phil @ evasive. You can only request the pump to go so high and it wont go any higher... I don't recall what pressure he managed to get it to but he did this by commanding a higher duty cycle... Considering it is in a closed loop function and you cannot modify this (closed loop meaning the ecu reads the current pressure... and when it changes it modifies the rate on its own) you will have poor luck modifying it. I would love for me to be wrong...

I can also tell you I have tried commanding 22MPa with the factory ecu and it doesn't go up any more than the standard 20MPa but this could also be related to OEM ecu logic having a maximum pressure allowance of 20MPa. Since I haven't disassembled the rom my self I cannot say for sure but considering how well it lines up the results im going to say its the ecu stopping it.
ok cheers
Crunk81us is offline   Reply With Quote
Old 06-23-2016, 12:08 AM   #37
steve99
Senior Member
 
steve99's Avatar
 
Join Date: Dec 2013
Drives: FT86
Location: Australia
Posts: 6,983
Thanks: 937
Thanked 4,375 Times in 2,612 Posts
Mentioned: 477 Post(s)
Tagged: 2 Thread(s)
If the motec ECU is locked and it is using speed density then to "adjust" you could offset either the IAT sensor (integrated in MAF i believe) or the MAP sensor readings to alter the "tune". This may be as simple as a series or parallel resistor but the adjustment would be fairly crude.

but you will need to research the charastics of the IAT and/or MAP sensors so your offsets work correctly


diagrams for illustration only







or




Last edited by steve99; 06-23-2016 at 12:30 AM.
steve99 is offline   Reply With Quote
Old 06-26-2016, 05:03 AM   #38
Crunk81us
Member
 
Join Date: May 2016
Drives: Toyota 86
Location: Australia
Posts: 39
Thanks: 8
Thanked 4 Times in 4 Posts
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quote:
Originally Posted by steve99 View Post
If the motec ECU is locked and it is using speed density then to "adjust" you could offset either the IAT sensor (integrated in MAF i believe) or the MAP sensor readings to alter the "tune". This may be as simple as a series or parallel resistor but the adjustment would be fairly crude.

but you will need to research the charastics of the IAT and/or MAP sensors so your offsets work correctly


diagrams for illustration only







or



pretty sure this would be on the bad side of the rules lol.
Crunk81us is offline   Reply With Quote
The Following User Says Thank You to Crunk81us For This Useful Post:
steve99 (06-26-2016)
 
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Delicious Tuning Flex Fuel Kit Mark 1+ Fuel Pressure Safety System DeliciousTuning Software Tuning 20 06-09-2016 06:21 AM
Fuel system questions. Boost-A-pump/stock fuel lines for engine swap Toxicmilk45 Engine, Exhaust, Transmission 4 12-14-2015 04:52 PM
High Pressure Fuel Pump Thread crazyfrenchbiker Engine, Exhaust, Transmission 10 09-09-2015 01:32 AM
High Pressure Fuel Pump Difference? Toyota vs. Subaru 86_ZN6 Engine, Exhaust, Transmission 18 06-03-2013 06:48 AM
Dynosty FR-S/BRZ Fuel System Upgrades! Deatschwerks DW65C Fuel Pump Dustin@Dynosty Engine, Exhaust, Bolt-Ons 3 08-21-2012 04:53 PM


All times are GMT -4. The time now is 03:47 PM.


Powered by vBulletin® Version 3.8.4
Copyright ©2000 - 2018, Jelsoft Enterprises Ltd.
Garage vBulletin Plugins by Drive Thru Online, Inc.