Stock MAF or Speed Density??

jsbrown923

New member
I have a question regarding stock MAF vs. Speed Density. Before I ask it, let me divulge what's going on with the car and my current situation.

So last week my turbo fried and I'm just overhauling the engine.

These are the parts I've ordered and are planning to put on:

STi Mod List

- Grimmspeed EBCS
- IAG stage 2 block
- IAG garret GT series turbo oil feed & avcs lines
- ETS STi full rotated kit upgrade w/ turbo manifold, up-pipe, downpipe, upper ic piping, intake, TiAL 44mm wastegate, garret gtx3076r .63 turbo (all V-Band)
- Cosworth high flow intake manifold
- AEM 320lph fuel pump
**already have Precision FMIC, ID1000cc injectors, Perrin fuel rails, AEM EMS v2, stage 1 gsc cams, mildly ported heads, tgv delete, ferrea valves, & ARP headstuds.

My question is should I stay with the Stock MAF or go Speed Density with my new ETS kit? My tuner says to stay with the stock MAF as he plans to open source tune the car. My thinking is why not go Speed Density since I already have the AEM v2, plus wouldn't my setup warrant Speed Density anyhow??

Thanks in advance.


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I'm running speed density and am of the opinion why not. Maybe your tuner doesn't know how or isn't comfortable with it. If you want to go SD and he won't do it let HOLYCRAPITSFAST tune for you as he is the one who tuned my car


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I actually went with a 83MM MAF at [MENTION=9]HolyCrapItsFast[/MENTION], recommendation. So Far its running well with the following mods.


3” turbo back no cat
tomei Headers
Deadbolt 20G
1000 CC injectors
83MM Maf
TGV deletes
Perin intake snorkel
Cobb Cold air box
Forged mortor.
New Case halfs
Manley ibeam rods
OEM heat treated forged crank
Manley forged pistons
CP rings
King bearings
ARP Head studs
New oil cooler
New Oil Pump
New gates racing timing belt, water pump tensioner, and pulley’s
Stock 04 sti Top Mount.
Omni power 3 bar MAP sensor.
MAC 3 port boost control solenoid.
CX Racing 2” aluminum radiator.
NGK 1 step colder spark plugs.
ACT street disc with Max extreme pressure plate and OEM Throughout Bearing, and pilot bearing.
Motor currently has just over 5000 Miles on it as well.
 

jsbrown923

New member
I actually went with a 83MM MAF at [MENTION=9]HolyCrapItsFast[/MENTION], recommendation. So Far its running well with the following mods.


3? turbo back no cat
tomei Headers
Deadbolt 20G
1000 CC injectors
83MM Maf
TGV deletes
Perin intake snorkel
Cobb Cold air box
Forged mortor.
New Case halfs
Manley ibeam rods
OEM heat treated forged crank
Manley forged pistons
CP rings
King bearings
ARP Head studs
New oil cooler
New Oil Pump
New gates racing timing belt, water pump tensioner, and pulley?s
Stock 04 sti Top Mount.
Omni power 3 bar MAP sensor.
MAC 3 port boost control solenoid.
CX Racing 2? aluminum radiator.
NGK 1 step colder spark plugs.
ACT street disc with Max extreme pressure plate and OEM Throughout Bearing, and pilot bearing.
Motor currently has just over 5000 Miles on it as well.

Nice! That sounds like a sweet setup you've got there! My tuner said he would rather open source with the stock MAF? He said I could always go with Speed Density later. Hopefully this is the right call.


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Nice! That sounds like a sweet setup you've got there! My tuner said he would rather open source with the stock MAF? He said I could always go with Speed Density later. Hopefully this is the right call.


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Just keep an eye on you MAF voltage if it starts getting close to 5V you will be at the upper end of what your stock MAF will be able to read. [MENTION=9]HolyCrapItsFast[/MENTION] will be able to explain better than I though.


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jsbrown923

New member
Just keep an eye on you MAF voltage if it starts getting close to 5V you will be at the upper end of what your stock MAF will be able to read. [MENTION=9]HolyCrapItsFast[/MENTION] will be able to explain better than I though.


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10-4. Thank you. Once everything is reassembled and the break in is done I'm gonna have it tuned and we will see what it's looking like. Thanks again for your insight.


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HolyCrapItsFast

Drinks beer!
The elephant in the room...

I don't think your tuner quite understands the nature of your beast. How does one "open source" tune an AEM Series 2 EMS. I would just set it up using speed density but you will also need an Omni 4 bar map sensor and an AEM intake temperature sensor mounted somewhere in the intake manifold. Very important.

If you where on the stock ECU I would say stay MAF and then Open Source would be an Okay solution; however your setup would require an 83mm MAF housing (intake)

Did you communicate to your tuner that you are using the AEM EMS?
 

jsbrown923

New member
The elephant in the room...

I don't think your tuner quite understands the nature of your beast. How does one "open source" tune an AEM Series 2 EMS. I would just set it up using speed density but you will also need an Omni 4 bar map sensor and an AEM intake temperature sensor mounted somewhere in the intake manifold. Very important.

If you where on the stock ECU I would say stay MAF and then Open Source would be an Okay solution; however your setup would require an 83mm MAF housing (intake)

Did you communicate to your tuner that you are using the AEM EMS?

Sorry I should have been more clear, the previous owner installed the AEM and it is what is currently being used. My tuner said he would prefer to switch back to the stock ecu and open source it for the new setup and use the stock MAF.


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jsbrown923

New member
I would imagine ETS hasn't started production on my turbo kit yet (just ordered it last Wednesday) so I could call them and tell them I want to change to Speed Density instead of the stock MAF, which leads me to my next question.... would ETS include the 4 bar map sensor and the an intake temp sensor or would I need to purchase those separately?


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I would imagine ETS hasn't started production on my turbo kit yet (just ordered it last Wednesday) so I could call them and tell them I want to change to Speed Density instead of the stock MAF, which leads me to my next question.... would ETS include the 4 bar map sensor and the an intake temp sensor or would I need to purchase those separately?


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Those are usually sold separately. I got my map sensor from amazon.


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HolyCrapItsFast

Drinks beer!
Reverting back to the stock ECU is probably a better way to go but now that I think into it more... this is a rotated kit correct? Does that accomodate a MAF because it certainly would not accomodate a stock setup. I have ever seen rotated kits on speed density tunes. In this instance I would go speed density to eliminate the intake all together and just run an air filter on the inlet of the turbo. In this case you would still need the 4 bar map sensor and the intake temp sensor. I don't know if the ETS come with any sensors.

If a MAF is going to be used, the stock size MAF will not do. You will definitely need an 83mm housing
 

jsbrown923

New member
It kinda sounds like Speed Density is a no brained here, haha. Surprise, I have another question.

Lol. Sooo let's say I decided I wanted to be tuned for e85 a) that would require Speed Density for sure right? (yes I know I'd need 1300cc injectors min) b) If I used the AEM v2, I could have an e85 map and a 93 octane map too right?


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HolyCrapItsFast

Drinks beer!
You can have E85 with any ECU or any strategy so that is not so much an issue. With the AEM V2 you can implement full flex fuel capability.

Silly Question... What year is your car.
 

jsbrown923

New member
You can have E85 with any ECU or any strategy so that is not so much an issue. With the AEM V2 you can implement full flex fuel capability.

Silly Question... What year is your car.

2005. I meant like if I wanted to switch back and forth between an e85 tune and a 93 octane tune, I could do that using a laptop via the AEM ?


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HolyCrapItsFast

Drinks beer!
For the AEM no and yes depending... just install a flex fuel sensor and let the EMS blend between 0% and 100% ethanol. It is fully flex fuel capable. If, for some reason, you wish to have separate tunes for 93 and ethanol, then you would need to switch maps with the lap top.

For open source you only have the choice of switching between 93 and ethanol with the lap top
 
Last edited:

jsbrown923

New member
For the AEM no and yes depending... just install a flex fuel sensor and let the EMS blend between 0% and 100% ethanol. It is fully flex fuel capable. If, for some reason, you wish to have separate tunes for 93 and ethanol, then you would need to switch maps with the lap top.

For open source you only have the choice of switching between 93 and ethanol with the lap top

Okk. Gotcha. Thank you clearing all that up. The subie world is all new to me, very confusing but I'm starting to learn ?? cheers


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jsbrown923

New member
For the AEM no and yes depending... just install a flex fuel sensor and let the EMS blend between 0% and 100% ethanol. It is fully flex fuel capable. If, for some reason, you wish to have separate tunes for 93 and ethanol, then you would need to switch maps with the lap top.

For open source you only have the choice of switching between 93 and ethanol with the lap top

Im having trouble finding a flex fuel sensor that is compatible with the AEM v2, most everything I see is compatible with the Cobb accessport. I however did find this sensor, I think it will work with my AEM v2, just wanted to run it by you and see before I order it.

https://m.summitracing.com/parts/av...-electronics&gclid=COS5mbfT-NICFYuNswodDl0NJA


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jsbrown923

New member
Buy this one, it will save you a bunch of cash...

http://www.ebay.com/itm/New-Genuine...ash=item21124ebbde:g:4KIAAOSwvg9XdPWQ&vxp=mtr

These are all the same sensors and they are all compatible with AEM. They are all made by one company so buying a branded sensor makes no sense these days. :tup:

Shit... I literally just ordered everything I need like an hour ago. Haha. Take a look and make sure I got everything I needed?

I got ETS to change my kit to speed density instead of stock MAF.

I ordered all of the following from AEM
- AEM 3.5 bar MAP sensor
- AEM intake temp sensor
- AEM flex fuel sensor w/ -6AN fittings all around and steel braided lines.

I think I should be all good for e85 now





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