I'm an electrical engineer and I program PLCs that run machines in a factory and I agree that the more real world feedback the better, better than any estimation we have instances where when an analog sensor fails there is a back up estimation program rung that it switches to till we get the new analog sensor in but it's not as good as the one with real world feedback. thanks you just saved me $150 I'm sticking with MAF (street driving DSM about 400hp)
My tuner friend always uses SD but for non rotated wrx setups pushing barely 300 I would guess. Can’t be convinced that MAF is better when you’re in range and it’s annoying lol
@@codythrasher3930 oh really? wow. Thank you for the amazing insight that's covered in the video. And no, not "very low hp". The 2008+ GR STi, can do 500whp on a factory MAF sensor with Cobb SF Intake. Dude, you're not going to come in here and act like you know something I don't. Because you don't.
Good stuff here, currently settings in my car, invidia R400, catted grimmspeed divorced DP, Cobb SF intake and 1 step colder sparks and dyno tune. Planning on getting ETS FMIC, Don't know if getting the 3 or 3.5, im going to run the VF48 turbo for a while before upgrading, grimmspeed up pipe with EWG, still debating between 38 and 44mm, as for the FMIC I was thinking on the Tial Bov with speed density but now that im watching your video im thinking about it.
I am going to be going with a Borgwarner SX257 rotated. It will be much easier for me to go speed density rather than maf as I won't have to build a proper maf capable intake for it but ideally I would like to do a hybrid setup.
Bruh, you don’t know that speed density is better.. even more so when the IAT is still at the MAF. You don’t know how many cars I’ve seen with an SD map, on a stockish turbo, maf still in place.
Nobody said speed density is more accurate than maf. People like speed density and use it a lot because it is easy to tune, needs a simpler setup and is more reliable. That's all, and that's what makes it better. And even tho speed density is technically less accurate than maf, it totally is accurate enough to run engines. Y'all need to remember that back in the days people used carburetors to run engines, and it was reliable despite being unprecise, and to this day there's engines with well over a thousand horsepower that are ran by carburetors. Also a couple nick picky things; "It depends where your iat sensor is" well yes, but it's know that the iat sensor should be as close to the throttle body as possible, so if you follow the rules, the iat virtually is on the same place no matter the car or setup. Second thing is that it's not really relevant to say you shouldn't go speed density while it's literally the most used kind of tuning in the aftermarket industry. And guess what, people do not have as much issues as they do with maf setups.
It is not easier to tune. It takes far more time and knowledge to properly determine an engine's VE at every load cell. It also takes more hardware to do properly that you can't do correctly without a dyno. It is not a simpler setup. It relies on more sensors and still does not compensate for changes in back pressure, wgdc, leaks, wear, humidity or baro pressure. MAF does all those. More reliable is highly debatable.
@@GetaDomTune It is easier to tune tho. I am not a tuner, but I know how to do a rough ve table to make a car run better before getting it professionnally tuned, I looked into maf tuning and it is definitely more complicated. Maybe it's not if you've been doing it for 15 years, but for a non trained person map seems more intuitive. And no, it doesn't compensate for changes in back pressure, waste gate duty cyle or things like that, but if you change any of this, even on a maf car, you should get it re-tuned, any tuner will tell you it's much safer to retune, letting an ecu compensate is not a good idea and leads to potential engine failure as it's not reliable and could fail at compensating. And yes, maf is the least reliable thing I've ever saw, 7 times out of 10 I see a car that runs like trash it's the maf that needs cleaning or replacing. Literally only seen once someone that needed to replace a map sensor.
@@imnota you don't need to do anything for MAF tuning and it can be done on the street. What's more intuitive than having a sensor actually measure the amount of air passed a point? Bam, done. MAF can compensate for lots more than you're giving it credit for. What you're tuning for in those situations isn't the MAF, it's the boost control system and changes in MBT. The air is still accurately measured otherwise. Failing to do proper maintenance, like cleaning a MAF, isn't the fault of the MAF, it's the fault of the user. Lastly, I have speed density on my own car, but it isn't just an inaccurate map based SD. My system is based on pressure ratio. It compares MAP and exhaust pressure. This is the most accurate way to do SD. It compensates for almost all those changes as well. However, no factory MAF ECU that's hacked to operate in a faux speed density is going to be able to do that. And that's what I'm referring to the most. I'm referring to speed density hacks performed on MAF based EMS. They aren't true speed density at all, and they're highly flawed. If you have a Subaru with an increasing VE table passed 14psi that's over 100%VE, it's clearly not an accurate system. No EJ is going over 105% VE. At 30psi, VE should be down around 75 to 80%
Hey dom, my build is an IAG 900 long-block, ETS rotated PTE 6266, e85 flex-fuel setup and supporting mods... I'm obviously going to max out the maf and will be going SD but I was wondering if you recommend doing a hybrid setup or just standard SD? I'll probably be giving you a call for one of your e-tunes when the car is finished (about a month or two) as I'm still waiting for the block and other goodies to arrive. Trying to piece together the last few items for the build. Thx dude!
Could you use a stand-alone ECU and have it recognize two MAFs so that you could use multiple sensors in different tubes that feed the same turbo? Since each sensor is only doing half the work, wouldn't it allow you to have good low end resolution as well as be able to read larger volumes of air coming into the engine? Genuine curiosity here.
That would not provide the result you are looking for. If you have two tubes, then at idle you have half of your already small amount of air running through each tube.
do you think some sort of flap with a light spring tension in the intake right behind the filter that sort of like some mass air units have would help a speed density set up....?
You just described an air flow meter. It's been used on injection systems since before map sensors existed. It's not the same as a MAF, it measures air volume rather than mass. Then it calculates the mass with inputs from the IAT and sometimes a barometric sensor. So it's not a whole lot different than speed density other than having a restriction in the airway.
You mention the Dom 1.5 on here, but at 18-19psi, I was hitting 4.98V on my MAF, targeting 11.2 in summer. Isn't it dangerous to be running so close to 5V? (04 STi). I was going to be completely out of sensor come winter time... I'm currently pure SD at 20psi, debating dialing it back to hybrid... Thanks!
I agree with the "probably not" thing, but your reasoning is questionable. Speed density isn't an estimation, it's a calculation. Granted, there are factors that can make these (and any) system less accurate. If you're making a lot of power, particularly in a high boost engine - a MAF sucks. But that's not the only reason they can suck or be inaccurate and a lot of it I see passed off as solid advice - and some of it even seems pretty damn reasonable, but it doesn't work. You mention a 4" intake pipe. Well, my engine from the factory was mass air - and has a 4" intake pipe with the smallest throttle body put on that engine. Some of the later ones deactivate cylinders - down to 4 cylinders, so it's not like the air can't be accurately measured through a 4" pipe via mass air sensor for a small(ish) 4 cylinder. But what you DO need, is that sensor in the middle of a long straight piece of pipe. You do not want it right by an elbow, throttle body, diameter change, or any other potential disturbance. Putting it right by a 90 degree elbow right where it enters the throttle body - you'd be WAY more accurate with a SD setup. Another thing I don't see mentioned is that the MAF itself can cause turbulence, and effect its own reading. Which is why if you're running a lot of boost, a MAF can be wildly inaccurate, where a SD can get you pretty much spot on - especially since you're trimming it with o2 sensor inputs. By wildly inaccurate I mean to the point of barely running - but idles great! Another commenter mentioned people going SD, but leaving the MAF in place because that's where the IAT is. I got a great laugh out of that one :D If you're that stupid, please don't work on your own car. Hire a tuner that knows something. My car - the one with the mass air on a 4" pipe from the factory? 5 wire MAF - meaning the IAT is (well WAS) there. Buy or make a breakout cable. Or cut the connector off - and put an IAT with the same range in an appropriate place. Mine is in the intake manifold behind the throttle plate. You want to measure intake air temperature, not ambient temp. Oh - and intercooler guys ... if I see you putting one between the turbo and intercooler I'm going to laugh at you. Anyway, I used to think the same way about MAF. And I was right too - except not always. A lot of things that work best for a daily driver go right out the window when you're talking about purpose built cars that don't have to be manageable for street driving. So yeah, you guys with a daily driven car with a cold air intake and fartcan muffler to make it a "racecar" - do not even remotely need a SD setup.
This must be the first video of mine you've watched. If it wasn't you wouldn't have spent twenty minutes writing this totally unnecessary comment that parrots my other videos. You'd also know that you're wrong and that I'll tell you about how wrong you are in an instant. SD is a calculation based off of 3 estimates. IAT and VE being the two largest. If you knew anything about engine management you'd know iat is part of an input into Charge temp, which is a total estimation. Shit it's even called Charge Temp Estimation
@@GetaDomTune By that standard, they're all estimates. You're guessing how much fuel an engine needs given any sensors inputs, which vary in accuracy depending on conditions. Especially a MAF when you've got a big cam with a lot of boost and the MAF can't tell which way is sideways. It's not called a charge temp estimate when you're directly reading the sensor. Which you can, and it's pretty accurate at determining air mass if you locate it in the intake, in the same cavity the map sensor reads from instead of somewhere like the air box.
Ok, so... is there a way to run a BOV on a '17 WRX without it running super rich when you let off it? Yes, it's vain to want to the noise. No, I don't want to sacrifice power and would like to avoid doing so... but the psssssttt... yeah. That. 😂
A BOV isn't a vanity item at all. When you let off, all that air being ramrodded down your intake suddenly hits the throttle plate and has nowhere to go. The turbo doesn't instantly spool down or "turn off" when you lift. I've seen engines swallow throttle plates. And yes, there IS a way to run a BOV without running rich on letoff, you'd run a recirculating bov. I think i'ts a lot of wasted effort over nothing. Why should I care if my engine spikes rich for a second when I let off? It's not under load at that point. That's probably why you dont really see them outside of some factory applications. Depending on what you're using your car of course - I'd say running rich on lift is the least of your worries.
Not full time. I would get the hybrid harness so you only use SD if you max your MAF sensor. Putting the IAT post intercooler is a good idea no matter the setup. I do it on MAF cars all the time
@@GetaDomTuneand on a Subaru using a Link you'd still suggest hooking up the MAF? Flex fuel 20G on 2.0L w/cobb SF intake. I was on the link forums today and very few people run Mafs even though the wrx and sti seem to have built in calibration on the Link platform unlike other makes and models. Everyone was saying making the MAF work wasn't worth it on a Link. But I was under the impression the best kinds of tunes are hybrid maf/SD, where maf handles idle and low RPM and load and SD is used for power pulls.
I'm an electrical engineer and I program PLCs that run machines in a factory and I agree that the more real world feedback the better, better than any estimation we have instances where when an analog sensor fails there is a back up estimation program rung that it switches to till we get the new analog sensor in but it's not as good as the one with real world feedback. thanks you just saved me $150 I'm sticking with MAF (street driving DSM about 400hp)
Thanks for this. I was doing a lot of research. It all makes sense now.
My tuner friend always uses SD but for non rotated wrx setups pushing barely 300 I would guess. Can’t be convinced that MAF is better when you’re in range and it’s annoying lol
Someone give this man a beer.. I keep saying the SAME THING!
It is better for tuning and more accurate. Maf is not accurate because it’s right at the filter
Hahahaha. That's exactly the opposite of the truth. Holy shit you're hilarious
@@GetaDomTune sorry I wasn’t more specific I guess. For a very low hp car yes maf is fine. But if your high hp and high reving you need speed density
@@codythrasher3930 oh really? wow. Thank you for the amazing insight that's covered in the video.
And no, not "very low hp".
The 2008+ GR STi, can do 500whp on a factory MAF sensor with Cobb SF Intake.
Dude, you're not going to come in here and act like you know something I don't. Because you don't.
Good stuff here, currently settings in my car, invidia R400, catted grimmspeed divorced DP, Cobb SF intake and 1 step colder sparks and dyno tune. Planning on getting ETS FMIC, Don't know if getting the 3 or 3.5, im going to run the VF48 turbo for a while before upgrading, grimmspeed up pipe with EWG, still debating between 38 and 44mm, as for the FMIC I was thinking on the Tial Bov with speed density but now that im watching your video im thinking about it.
I am going to be going with a Borgwarner SX257 rotated. It will be much easier for me to go speed density rather than maf as I won't have to build a proper maf capable intake for it but ideally I would like to do a hybrid setup.
absolutely. If it doesn't fit, it doesn't fit.
They made it for a good reason so leave us alone
Roger that! Lol
Bruh, you don’t know that speed density is better.. even more so when the IAT is still at the MAF. You don’t know how many cars I’ve seen with an SD map, on a stockish turbo, maf still in place.
I move the IAT even on MAF cars.
Do u like the hybrid system cuz I want to move to it cuz it uses both and I really like that
TuRbO- KiWi is it's needed, yes.
Nobody said speed density is more accurate than maf.
People like speed density and use it a lot because it is easy to tune, needs a simpler setup and is more reliable. That's all, and that's what makes it better.
And even tho speed density is technically less accurate than maf, it totally is accurate enough to run engines. Y'all need to remember that back in the days people used carburetors to run engines, and it was reliable despite being unprecise, and to this day there's engines with well over a thousand horsepower that are ran by carburetors.
Also a couple nick picky things; "It depends where your iat sensor is" well yes, but it's know that the iat sensor should be as close to the throttle body as possible, so if you follow the rules, the iat virtually is on the same place no matter the car or setup.
Second thing is that it's not really relevant to say you shouldn't go speed density while it's literally the most used kind of tuning in the aftermarket industry. And guess what, people do not have as much issues as they do with maf setups.
It is not easier to tune. It takes far more time and knowledge to properly determine an engine's VE at every load cell. It also takes more hardware to do properly that you can't do correctly without a dyno.
It is not a simpler setup. It relies on more sensors and still does not compensate for changes in back pressure, wgdc, leaks, wear, humidity or baro pressure. MAF does all those.
More reliable is highly debatable.
@@GetaDomTune
It is easier to tune tho. I am not a tuner, but I know how to do a rough ve table to make a car run better before getting it professionnally tuned, I looked into maf tuning and it is definitely more complicated. Maybe it's not if you've been doing it for 15 years, but for a non trained person map seems more intuitive.
And no, it doesn't compensate for changes in back pressure, waste gate duty cyle or things like that, but if you change any of this, even on a maf car, you should get it re-tuned, any tuner will tell you it's much safer to retune, letting an ecu compensate is not a good idea and leads to potential engine failure as it's not reliable and could fail at compensating.
And yes, maf is the least reliable thing I've ever saw, 7 times out of 10 I see a car that runs like trash it's the maf that needs cleaning or replacing. Literally only seen once someone that needed to replace a map sensor.
@@imnota you don't need to do anything for MAF tuning and it can be done on the street. What's more intuitive than having a sensor actually measure the amount of air passed a point? Bam, done.
MAF can compensate for lots more than you're giving it credit for. What you're tuning for in those situations isn't the MAF, it's the boost control system and changes in MBT. The air is still accurately measured otherwise.
Failing to do proper maintenance, like cleaning a MAF, isn't the fault of the MAF, it's the fault of the user.
Lastly, I have speed density on my own car, but it isn't just an inaccurate map based SD. My system is based on pressure ratio. It compares MAP and exhaust pressure. This is the most accurate way to do SD. It compensates for almost all those changes as well. However, no factory MAF ECU that's hacked to operate in a faux speed density is going to be able to do that.
And that's what I'm referring to the most. I'm referring to speed density hacks performed on MAF based EMS. They aren't true speed density at all, and they're highly flawed.
If you have a Subaru with an increasing VE table passed 14psi that's over 100%VE, it's clearly not an accurate system. No EJ is going over 105% VE. At 30psi, VE should be down around 75 to 80%
@@GetaDomTune are you a tuner?
@@AblationMusic for over 25 years, yes
Hey dom, my build is an IAG 900 long-block, ETS rotated PTE 6266, e85 flex-fuel setup and supporting mods... I'm obviously going to max out the maf and will be going SD but I was wondering if you recommend doing a hybrid setup or just standard SD? I'll probably be giving you a call for one of your e-tunes when the car is finished (about a month or two) as I'm still waiting for the block and other goodies to arrive. Trying to piece together the last few items for the build. Thx dude!
I would just go standard SD.
Could you use a stand-alone ECU and have it recognize two MAFs so that you could use multiple sensors in different tubes that feed the same turbo? Since each sensor is only doing half the work, wouldn't it allow you to have good low end resolution as well as be able to read larger volumes of air coming into the engine?
Genuine curiosity here.
That would not provide the result you are looking for.
If you have two tubes, then at idle you have half of your already small amount of air running through each tube.
do you think some sort of flap with a light spring tension in the intake right behind the filter that sort of like some mass air units have would help a speed density set up....?
Not in any way
You just described an air flow meter. It's been used on injection systems since before map sensors existed. It's not the same as a MAF, it measures air volume rather than mass. Then it calculates the mass with inputs from the IAT and sometimes a barometric sensor. So it's not a whole lot different than speed density other than having a restriction in the airway.
You mention the Dom 1.5 on here, but at 18-19psi, I was hitting 4.98V on my MAF, targeting 11.2 in summer. Isn't it dangerous to be running so close to 5V? (04 STi). I was going to be completely out of sensor come winter time... I'm currently pure SD at 20psi, debating dialing it back to hybrid... Thanks!
The GR MAF can support 500hp with a Cobb SF intake..
The GD is limited around 380whp or so.
In your case, you do hybrid SD up top.
@@GetaDomTune Could you use the GR MAF on a GD?
@@btvaalburg I haven't tried. It would require changing the plug on the harness.
Wouldn't it be more accurate if the maf was as close to the throttle body as possible?
In theory, but you'd have issues with pulsations giving you bad readings
@@GetaDomTune so approximately how close can we get the maf to the throttle without getting wonky readings?
@@_Epictetus_ couple feet. But on a turbo car, blow through MAF is horrendous to tune due to rapid changes in air density
I agree with the "probably not" thing, but your reasoning is questionable. Speed density isn't an estimation, it's a calculation. Granted, there are factors that can make these (and any) system less accurate.
If you're making a lot of power, particularly in a high boost engine - a MAF sucks. But that's not the only reason they can suck or be inaccurate and a lot of it I see passed off as solid advice - and some of it even seems pretty damn reasonable, but it doesn't work.
You mention a 4" intake pipe. Well, my engine from the factory was mass air - and has a 4" intake pipe with the smallest throttle body put on that engine. Some of the later ones deactivate cylinders - down to 4 cylinders, so it's not like the air can't be accurately measured through a 4" pipe via mass air sensor for a small(ish) 4 cylinder. But what you DO need, is that sensor in the middle of a long straight piece of pipe. You do not want it right by an elbow, throttle body, diameter change, or any other potential disturbance. Putting it right by a 90 degree elbow right where it enters the throttle body - you'd be WAY more accurate with a SD setup.
Another thing I don't see mentioned is that the MAF itself can cause turbulence, and effect its own reading. Which is why if you're running a lot of boost, a MAF can be wildly inaccurate, where a SD can get you pretty much spot on - especially since you're trimming it with o2 sensor inputs. By wildly inaccurate I mean to the point of barely running - but idles great!
Another commenter mentioned people going SD, but leaving the MAF in place because that's where the IAT is. I got a great laugh out of that one :D If you're that stupid, please don't work on your own car. Hire a tuner that knows something. My car - the one with the mass air on a 4" pipe from the factory? 5 wire MAF - meaning the IAT is (well WAS) there. Buy or make a breakout cable. Or cut the connector off - and put an IAT with the same range in an appropriate place. Mine is in the intake manifold behind the throttle plate. You want to measure intake air temperature, not ambient temp. Oh - and intercooler guys ... if I see you putting one between the turbo and intercooler I'm going to laugh at you.
Anyway, I used to think the same way about MAF. And I was right too - except not always. A lot of things that work best for a daily driver go right out the window when you're talking about purpose built cars that don't have to be manageable for street driving.
So yeah, you guys with a daily driven car with a cold air intake and fartcan muffler to make it a "racecar" - do not even remotely need a SD setup.
This must be the first video of mine you've watched. If it wasn't you wouldn't have spent twenty minutes writing this totally unnecessary comment that parrots my other videos. You'd also know that you're wrong and that I'll tell you about how wrong you are in an instant. SD is a calculation based off of 3 estimates. IAT and VE being the two largest. If you knew anything about engine management you'd know iat is part of an input into Charge temp, which is a total estimation. Shit it's even called Charge Temp Estimation
@@GetaDomTune By that standard, they're all estimates. You're guessing how much fuel an engine needs given any sensors inputs, which vary in accuracy depending on conditions. Especially a MAF when you've got a big cam with a lot of boost and the MAF can't tell which way is sideways.
It's not called a charge temp estimate when you're directly reading the sensor. Which you can, and it's pretty accurate at determining air mass if you locate it in the intake, in the same cavity the map sensor reads from instead of somewhere like the air box.
@@notsure7874 nice try, amigo, but no.
Keep learning
@@GetaDomTune Ok will do - every day.
You keep on tuning grocery getters. Let us know when you''ve got one over 700hp running mass air.
Do u have any experience with Cobbs hybrid mode which uses both maf and map
Katie Walsh yes, much.
Ok, so... is there a way to run a BOV on a '17 WRX without it running super rich when you let off it?
Yes, it's vain to want to the noise. No, I don't want to sacrifice power and would like to avoid doing so... but the psssssttt... yeah. That. 😂
No
@@GetaDomTune well shit. I'll have to find my thrills elsewhere. 😂 Thank you!!
A BOV isn't a vanity item at all. When you let off, all that air being ramrodded down your intake suddenly hits the throttle plate and has nowhere to go. The turbo doesn't instantly spool down or "turn off" when you lift. I've seen engines swallow throttle plates.
And yes, there IS a way to run a BOV without running rich on letoff, you'd run a recirculating bov. I think i'ts a lot of wasted effort over nothing. Why should I care if my engine spikes rich for a second when I let off? It's not under load at that point. That's probably why you dont really see them outside of some factory applications.
Depending on what you're using your car of course - I'd say running rich on lift is the least of your worries.
Good info man make more vids like this
I was about to buy the kit for this speed density. I have an fp black on the way should I do it? 2019 sti
Not full time. I would get the hybrid harness so you only use SD if you max your MAF sensor. Putting the IAT post intercooler is a good idea no matter the setup. I do it on MAF cars all the time
Dominic Acia I put it on the ets intercooler pipe. I also have an hks bov, will also be running flex fuel have everything for it.
At what point is the MAF limited on the 2002-2005 WRX
300g/s is the hard ECU cap so 300whp-ish.
@@GetaDomTune With an aftermarket ECU, say a Link, can the 02-05 MAF go beyond that? Or is SD the only option realistically? Thank you for help.
@@K3rm1tFr0g yes other ecu can go passed 300
@@GetaDomTuneand on a Subaru using a Link you'd still suggest hooking up the MAF? Flex fuel 20G on 2.0L w/cobb SF intake. I was on the link forums today and very few people run Mafs even though the wrx and sti seem to have built in calibration on the Link platform unlike other makes and models. Everyone was saying making the MAF work wasn't worth it on a Link. But I was under the impression the best kinds of tunes are hybrid maf/SD, where maf handles idle and low RPM and load and SD is used for power pulls.
@@K3rm1tFr0g You can do either. I like MAF, but if you have a bov, then it's not good
So, what would be your take on a blow thru style maf?
I don't like blow thru. It is very sensitive and needs to be done right. Nobody does it right. It wouldn't provide any gain over draw thru MAF.