Full throttle Electric Supercharger Build Thread

[Target70]

Just as a reminder, this was the dyno I was quoting:




Well thanks for the insight. I think I brought this up, because I almost never floor it. My last car was kind of touchy, either worn out injectors or electronics.. and flooring it was usually not as powerful as partial throttle. I actually had to modulate the throttle until I felt surges of power. As of now, I notice even in the frs I still don't floor it, I roll in to it as the revs climb, and don't think I often go over 50~60% throttle. or over 5k rpm (though that may change now that I swapped my N1 cat-back back to stock) too much noise = too much unwanted attention.
Any way, since I basically live at half throttle, I figured I would be constantly draining the batteries with drag reduction, or feeling an even bigger loss in power between my most used revs (3k to 5k), (yes, unfortunately that's the torque dip)

I think I would typically use the ESC to power out of corners in the twisties, or passing. That's why after all the other options I am most interested in the ESC, Low End Torque FTW. If you guys ever finish dialing in the TQ300 not to fry the maf with over-boost, because it seems to hold a little more boost as the revs climb, I'll be sold. +no oil lines, cooling lines, inter-cooler or piping, no turbo blankets, or belt problems.

Gary: Drag reduction works very well. The pulse lasts about a second and after it' has pulsed it reviews the MP and if necessary, pulses again.

I understand the hardware but the software(all software) makes me go brain-dead. what is the MP? and what exactly is it looking for to cause DR to kick in? I didn't even know it had a vacuum tube going to the motor controller till you told me above. on a side note I still have to figure out the whole software tuning, there seems to be so many options I am not sure what will work best with the ESC. With my old OBDI there was either piggyback stuff, or an AEM ECU. This OBDII software flash stuff with paired with electric throttle, vvti, Direct + port injection.. BOOM, mind blown

Fenton: Adding y's and solenoids to bypass the compressor will more than likely create problems with daily driveability in terms of idle and bogging.

I agree it could get complex, and complexity leads to failure. that's why I was opting for the KISS method, no vacuum lines, no electricity, no solenoids, just simple physics, basically the same thing as PCV. But agree also that I don't know enough to insure that it would never cause a problem.

Robftss: Fuel economy: Fuel is injected as per metered air not pedal postiion. By-pass: no spring required on flapper valve delta P's take care of that.

you have to admit though that there is a correlation between pedal position and amount of metered air.

I have no idea what you just said about the delta P's.. tried googling it and got a delta urinal flush valve. but I would agree that any air flow trying to flow backwards would most likely force the flapper closed of on its own. The benefit though is if the batteries ever run out WOT at high rpm(extremely unlikely on the street unless going for top speed run on interstate/don't try this at home kids), there would definitely be a drag to the engine, and with a bypass, the natural vacuum would create a seamless transition from boost drop off to natural aspiration.

[fenton]

Originally Posted by Target70

Just as a reminder, this was the dyno I was quoting:




Well thanks for the insight. I think I brought this up, because I almost never floor it. My last car was kind of touchy, either worn out injectors or electronics.. and flooring it was usually not as powerful as partial throttle. I actually had to modulate the throttle until I felt surges of power. As of now, I notice even in the frs I still don't floor it, I roll in to it as the revs climb, and don't think I often go over 50~60% throttle. or over 5k rpm (though that may change now that I swapped my N1 cat-back back to stock) too much noise = too much unwanted attention.
Any way, since I basically live at half throttle, I figured I would be constantly draining the batteries with drag reduction, or feeling an even bigger loss in power between my most used revs (3k to 5k), (yes, unfortunately that's the torque dip)

I think I would typically use the ESC to power out of corners in the twisties, or passing. That's why after all the other options I am most interested in the ESC, Low End Torque FTW. If you guys ever finish dialing in the TQ300 not to fry the maf with over-boost, because it seems to hold a little more boost as the revs climb, I'll be sold. +no oil lines, cooling lines, inter-cooler or piping, no turbo blankets, or belt problems.

Gary: Drag reduction works very well. The pulse lasts about a second and after it' has pulsed it reviews the MP and if necessary, pulses again.

I understand the hardware but the software(all software) makes me go brain-dead. what is the MP? and what exactly is it looking for to cause DR to kick in? I didn't even know it had a vacuum tube going to the motor controller till you told me above. on a side note I still have to figure out the whole software tuning, there seems to be so many options I am not sure what will work best with the ESC. With my old OBDI there was either piggyback stuff, or an AEM ECU. This OBDII software flash stuff with paired with electric throttle, vvti, Direct + port injection.. BOOM, mind blown

Fenton: Adding y's and solenoids to bypass the compressor will more than likely create problems with daily driveability in terms of idle and bogging.

I agree it could get complex, and complexity leads to failure. that's why I was opting for the KISS method, no vacuum lines, no electricity, no solenoids, just simple physics, basically the same thing as PCV. But agree also that I don't know enough to insure that it would never cause a problem.

Robftss: Fuel economy: Fuel is injected as per metered air not pedal postiion. By-pass: no spring required on flapper valve delta P's take care of that.

you have to admit though that there is a correlation between pedal position and amount of metered air.

I have no idea what you just said about the delta P's.. tried googling it and got a delta urinal flush valve. but I would agree that any air flow trying to flow backwards would most likely force the flapper closed of on its own. The benefit though is if the batteries ever run out WOT at high rpm(extremely unlikely on the street unless going for top speed run on interstate/don't try this at home kids), there would definitely be a drag to the engine, and with a bypass, the natural vacuum would create a seamless transition from boost drop off to natural aspiration.

Thanks for the awesome and in depth response Target70.

If you never go above 50 percent throttle you will not run into a problem using drag reduction. At 50 percent throttle the charger isn't a restriction yet. Where drag reduction kicks in is when you ask for ALL NA power (about 75 to 85 percent throttle). You have to remember that that dyno is done at WOT....at 5000 rpm and WOT you are losing about 5 to 7 HP.....if you went to 50percent throttle and weren't trying to pass the charger would barely cause a drop.

In any regard it is impossible to drain the battery using DR if you choose to use ALL you NA power. I have used it for 2 minutes up a steep mountain pass as a test and the drain is only slightly higher than the recharge.

Once again, thanks for the awesome response, you raise some great questions that all can benefit from.

Sent from my HTC One using Tapatalk

[Robftss]

"you have to admit though that there is a correlation between pedal position and amount of metered air."



During part throttle fuelling is based on the O2 sensor to maintain stoich, everything else is ignored.

At some point near WOT , maximum power, MAF and/or MAP referenced tables are used for fuelling requirements.

This is typical of EFI engines, those more intimate with the FA20 ECU will have more insight.

[Coheed]

Originally Posted by Robftss

"you have to admit though that there is a correlation between pedal position and amount of metered air."



During part throttle fuelling is based on the O2 sensor to maintain stoich, everything else is ignored.

At some point near WOT , maximum power, MAF and/or MAP referenced tables are used for fuelling requirements.

This is typical of EFI engines, those more intimate with the FA20 ECU will have more insight.

O2 sensor feedback is used to fine-tune fueling requirements. MAF tables are still utilized as the primary source for fuel and timing requirements. During closed-loop the O2 provides changes to the STFT tables that will slightly alter AFR based on the maf readings and scaling.

At WOT the O2 was generally ignored with older engines, but the FA20 still utilizes the wideband for fueling adjustments. This is a trend being seen with more wideband-equipped cars.

[s2d4]

Originally Posted by Coheed

At WOT the O2 was generally ignored with older engines, but the FA20 still utilizes the wideband for fueling adjustments. This is a trend being seen with more wideband-equipped cars.

Apparently it lacks accuracy under AFR 12 and open loop ignores the O2 sensor and just use the open loop targets to calculate fueling requirements.
At WOT, your throttle position is greater than the requirement to go from close to open loop according to what I've read over at RR forum.

[Robftss]

Thanks, @Coheed & @s2d4

Does the ECU use throttle pedal position to adjust fuel requirements?

The MAF based VW held stoich in closed loop even with some MAF voltage manipulation...richened in open loop.

Rob.

[jamesm]

Originally Posted by Coheed

At WOT the O2 was generally ignored with older engines, but the FA20 still utilizes the wideband for fueling adjustments. This is a trend being seen with more wideband-equipped cars.

this is not correct. there is no full-time closed loop fuel control in the stock rom, and there couldn't be, as the stock afr targets are lower than the floor of the stock o2 scaling.

[jamesm]

Originally Posted by Robftss

Thanks, @Coheed & @s2d4

Does the ECU use throttle pedal position to adjust fuel requirements?

The MAF based VW held stoich in closed loop even with some MAF voltage manipulation...richened in open loop.

Rob.

the subaru open/closed loop transition strategy is pretty complex when stock. most people end up disabling the timers so that it's dictated entirely by the fuel map and minumum open loop afr.

there are throttle-based fueling compensations, both for throttle delta and an open loop compensation. i have disabled the open loop throttle compensation in my rom.

[Robftss]

Originally Posted by jamesm

the subaru open/closed loop transition strategy is pretty complex when stock. most people end up disabling the timers so that it's dictated entirely by the fuel map and minumum open loop afr.

there are throttle-based fueling compensations, both for throttle delta and an open loop compensation. i have disabled the open loop throttle compensation in my rom.

"throttle delta" aka throttle change/time?

You are obviously a 'self tuner', so let me ask you... during steady state power @ say 40% TPS and an airflow restriction of say +5% relative to the norm, will the 'throttle fueling compensation' intervene because the MAF's metered value is 5% less? Or will the MAF's metered air in combination with the O2 provide stoich regardless of TPS? In short, will it burn more fuel?

Thanks!

[jamesm]

Originally Posted by Robftss

"throttle delta" aka throttle change/time?

You are obviously a 'self tuner', so let me ask you... during steady state power @ say 40% TPS and an airflow restriction of say +5% relative to the norm, will the 'throttle fueling compensation' intervene because the MAF's metered value is 5% less? Or will the MAF's metered air in combination with the O2 provide stoich regardless of TPS? In short, will it burn more fuel?

Thanks!

yes, the throttle delta param (which can be logged by ecutek) is a measure of the rate of throttle change.

to answer your question, no. in a maf-based calculation, the ecu is estimating load using the maf output, through the maf scaling table. if you are flowing 5% less air for any reason, the maf will reflect this. the exception is if you have a post-maf air leak or something like that.

you'll probably want to scale the maf afterwards to keep the trims low, but you'll always hit your target in open loop. the trim range on these ecu's stock is +/-40%.

[Robftss]

Originally Posted by jamesm

yes, the throttle delta param (which can be logged by ecutek) is a measure of the rate of throttle change.

to answer your question, no. in a maf-based calculation, the ecu is estimating load using the maf output, through the maf scaling table. if you are flowing 5% less air for any reason, the maf will reflect this. the exception is if you have a post-maf air leak or something like that.

you'll probably want to scale the maf afterwards to keep the trims low, but you'll always hit your target in open loop. the trim range on these ecu's stock is +/-40%.

Got it! Rapid throttle change...brief extra fuel compensation.

5% less MAF signal = 5% less fuel delivered. Same fuel for the same load.

Thanks.

[Coheed]

Originally Posted by jamesm

this is not correct. there is no full-time closed loop fuel control in the stock rom, and there couldn't be, as the stock afr targets are lower than the floor of the stock o2 scaling.

This is interesting. I was under the assumption the FA20 used a Wideband sensor. Usually these read lower than a 12:1. I've worked with other vehicles where the O2 is still used for feedback when a conventional system would have already engaged open-loop.

This is all learning for me. I haven't personally tuned anything this new in a performance setting.

When I tuned other MAF-based systems the TPS was generally useless. It helped the ECU maintain idle, and was used for shifting points in AT vehicles. The TPS in the BRZ is a lot different because of the TAC. This TPS is used primarily as a diagnostic tool and idle with some feedback for fueling ( I would assume). Otherwise, speed-density tunes will utilize the TPS for VE tables.

If Subaru uses MAF to calculate airflow, it interests me a lot to see that the ECU is so dependent on CTS, TPS, MAP etc for fueling requirements. Many people require tuning to fully reap the benefits of extra airflow. This is a trait of a speed-density based tune. Requiring a re-tune with any modification which could alter the VE of the engine.

So with all the other sensors, is the ECU using the MAF as the main sensor or the MAP?

[jamesm]

Originally Posted by Coheed

This is interesting. I was under the assumption the FA20 used a Wideband sensor. Usually these read lower than a 12:1. I've worked with other vehicles where the O2 is still used for feedback when a conventional system would have already engaged open-loop.

This is all learning for me. I haven't personally tuned anything this new in a performance setting.

When I tuned other MAF-based systems the TPS was generally useless. It helped the ECU maintain idle, and was used for shifting points in AT vehicles. The TPS in the BRZ is a lot different because of the TAC. This TPS is used primarily as a diagnostic tool and idle with some feedback for fueling ( I would assume). Otherwise, speed-density tunes will utilize the TPS for VE tables.

If Subaru uses MAF to calculate airflow, it interests me a lot to see that the ECU is so dependent on CTS, TPS, MAP etc for fueling requirements. Many people require tuning to fully reap the benefits of extra airflow. This is a trait of a speed-density based tune. Requiring a re-tune with any modification which could alter the VE of the engine.

So with all the other sensors, is the ECU using the MAF as the main sensor or the MAP?

the stock tune is 100% maf-based, aside from cranking which references the map sensor.

[Urmyson]

Has anyone done any testing with headers yet?