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AFR readings


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#21 mbruneaux

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Posted 21 September 2017 - 11:48 AM

View PostTurbo Cary, on 20 September 2017 - 06:27 PM, said:

I got a O2 sensor plug to cap where the stock one went. I didn't want to put the wideband there because the heat would kill it.

The instructions say to install it at least 36 inches from the turbo.....
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#22 Zoggy87

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Posted 21 September 2017 - 12:15 PM

I have same setup. I'm running 41 psi. I use maft and idle is perfect. Only place mine is lean is on cruising. So I don't think the 55 is to small, just it's a slightly different flow rate than factory at same psi. With tuning it should be fine. Only reason I haven't dialed it in is I just got gen 2 and will spend my time in that system.

#23 mbruneaux

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Posted 21 September 2017 - 12:31 PM

View PostZoggy87, on 21 September 2017 - 12:15 PM, said:

I have same setup. I'm running 41 psi. I use maft and idle is perfect. Only place mine is lean is on cruising. So I don't think the 55 is to small, just it's a slightly different flow rate than factory at same psi. With tuning it should be fine. Only reason I haven't dialed it in is I just got gen 2 and will spend my time in that system.

I have a Gen2 also and want to make sure nothing is wrong before I install it.  Are you putting your MAF pre or post turbo?  I have seen it in the intercooler piping but would think it is affected by pressure changes.

Edited by mbruneaux, 21 September 2017 - 12:32 PM.

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1989 Chrysler Conquest TSi (Project Race Car) Build thread http://www.starquest...opic=147910&hl=
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#24 importwarrior

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Posted 21 September 2017 - 06:37 PM

I am running a 650 cc and 1050 cc and a MAF-T no issues.
Innovate wide band
Idle is 13.5
Cruise is about 14.4 to 14.7
wide open is about 11.3 - 11.5

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#25 Zoggy87

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Posted 21 September 2017 - 11:04 PM

View Postmbruneaux, on 21 September 2017 - 12:31 PM, said:



I have a Gen2 also and want to make sure nothing is wrong before I install it.  Are you putting your MAF pre or post turbo?  I have seen it in the intercooler piping but would think it is affected by pressure changes.

My maf is post turbo, on cold side of intercooler. I haven't seen much issue. I did it this way so I can do a bov but I'm on the fence like you are. I'm curious if pull through would give any better performance. I think I'm going to end up going no bov in the end anyway. I like the shutter sound anyway. I'm running 550cc/950cc. I didn't have as much issue wish cruise afr until I installed these GM's. I may need to turn fuel pressure up to flow more and then readjust idle and full. But like I said, I don't want to spend much time on gen 1 when I already have gen 2 waiting to be installed


#26 Turbo Cary

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Posted 24 September 2017 - 07:10 PM

View Postmbruneaux, on 21 September 2017 - 12:31 PM, said:



I have a Gen2 also and want to make sure nothing is wrong before I install it.  Are you putting your MAF pre or post turbo?  I have seen it in the intercooler piping but would think it is affected by pressure changes.

A blow through setup is more accurate than a draw through type. You would be measuring the air flow that the turbo is putting out versus what it is drawing in. Another benefit to blow through is that as long as the blow off valve is before the mass air flow sensor then you can vent it to atmosphere without having a risk of a engine stall event.

Having ran a Maf translator the whole time as draw through, I would have preferred for it to be blow through. I feel my tune would have been more accurate and ran a little more stable. But the draw through setup never let me down.

#27 Fuze

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Posted 26 September 2017 - 07:31 AM

View PostZoggy87, on 21 September 2017 - 11:04 PM, said:

I think I'm going to end up going no bov in the end anyway. I like the shutter sound anyway.

That's the sound of your turbo's oil seals telling you they're going to let go when you least expect it!

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#28 mbruneaux

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Posted 26 September 2017 - 07:41 AM

View PostFuze, on 26 September 2017 - 07:31 AM, said:

That's the sound of your turbo's oil seals telling you they're going to let go when you least expect it!

Are you saying the "proper" or for the sake of longevity a pre-turbo MAF and a blow off valve would be best?  Is a blow off valve and boost controller the same thing?  I have a Lower Shores manual boost controller installed. Pardon my ignorance but I need to learn a lot more about the system.
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2002 Discovery II SE7 (Wife's progeny wagon and tow vehicle)

Second place is S*** place , eh.  - Stéphane Peterhansel

#29 Zoggy87

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Posted 26 September 2017 - 07:45 AM

View PostFuze, on 26 September 2017 - 07:31 AM, said:



That's the sound of your turbo's oil seals telling you they're going to let go when you least expect it!

That's what some say, but there's no definitive proof it actually causes any significant damage. I've read both sides and both swear their way. It really comes down to preference. The only benefit that's proven is less turbo spool down.

#30 Zoggy87

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Posted 26 September 2017 - 07:49 AM

View Postmbruneaux, on 26 September 2017 - 07:41 AM, said:



Are you saying the "proper" or for the sake of longevity a pre-turbo MAF and a blow off valve would be best?  Is a blow off valve and boost controller the same thing?  I have a Lower Shores manual boost controller installed. Pardon my ignorance but I need to learn a lot more about the system.

A bov is a device that allows the built up pressure in the intake pipes to be released when you let off the gas as to prevent turbo surge that causes the turbo to slow down much quicker... And some think it prevents premature turbo failures. A boost controller is just that. It controls how much boost the system makes via increasing or decreasing the amount of pressure the turbos Watergate sees. They see separate devices.

#31 Zoggy87

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Posted 26 September 2017 - 07:53 AM

View PostTurbo Cary, on 24 September 2017 - 07:10 PM, said:



A blow through setup is more accurate than a draw through type. You would be measuring the air flow that the turbo is putting out versus what it is drawing in. Another benefit to blow through is that as long as the blow off valve is before the mass air flow sensor then you can vent it to atmosphere without having a risk of a engine stall event.

Having ran a Maf translator the whole time as draw through, I would have preferred for it to be blow through. I feel my tune would have been more accurate and ran a little more stable. But the draw through setup never let me down.

I believe this is a wrong evaluation. A maf sensor measures the mass of the air moving... Meaning the reading theoretically should be the same draw through or push through. The amount of air moving didn't change.. And I've actually read that some inaccuracies can occur due to blow through because the design being for draw through. You would think if blow through was better, all the manufacturers would stop using draw through.

#32 Zoggy87

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Posted 26 September 2017 - 07:59 AM

And fuze I'm talking in regards to low boost systems like our cars have. There's a big difference in 7-10 psi surge and 20-30.

Edited by Zoggy87, 26 September 2017 - 08:00 AM.


#33 Turbo Cary

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Posted 26 September 2017 - 02:12 PM

View PostZoggy87, on 26 September 2017 - 07:53 AM, said:



I believe this is a wrong evaluation. A maf sensor measures the mass of the air moving... Meaning the reading theoretically should be the same draw through or push through. The amount of air moving didn't change.. And I've actually read that some inaccuracies can occur due to blow through because the design being for draw through. You would think if blow through was better, all the manufacturers would stop using draw through.

I guess it comes down to ECU design and system operation. Blow through setups read the mass of the air entering the engine versus entering the turbo. Same air but different temperature and pressure. I agree with your statement in terms of manufacturers using draw through but that also comes down to part design as well. A GM maf has a metal housing versus plastic ones molded with air box lids etc. Either way will work fine. Intake air temps being read will be higher if inside a pressure pipe.

Best way to tell if one is more efficient than the other is to do a dyno run with both setups and some good data logging.

#34 Zoggy87

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Posted 26 September 2017 - 05:16 PM

View PostTurbo Cary, on 26 September 2017 - 02:12 PM, said:



I guess it comes down to ECU design and system operation. Blow through setups read the mass of the air entering the engine versus entering the turbo. Same air but different temperature and pressure. I agree with your statement in terms of manufacturers using draw through but that also comes down to part design as well. A GM maf has a metal housing versus plastic ones molded with air box lids etc. Either way will work fine. Intake air temps being read will be higher if inside a pressure pipe.

Best way to tell if one is more efficient than the other is to do a dyno run with both setups and some good data logging.

Regardless, the amount of air entering the turbo is the exact same amount entering the engine.... As long as the engine can flow the amount given it. Turbos compress air, they don't create it.

#35 mbruneaux

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Posted 27 September 2017 - 10:07 AM

Found this on another site concerning draw through vs. blow through MAFs.   http://forums.corral...hrough-maf.html

Edited by mbruneaux, 27 September 2017 - 10:08 AM.

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#36 mbruneaux

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Posted 30 September 2017 - 09:13 AM

Set the AEM to PO4 and the readings are much more stable.  It's definitely too lean at idle and early throttle (15 or 16) and rich at full throttle (9 or 10).  I need to get the MAFT installed to start adjusting fuel.

I appreciate everyone's input and advice.

Edited by mbruneaux, 30 September 2017 - 09:13 AM.

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1989 Chrysler Conquest TSi (Project Race Car) Build thread http://www.starquest...opic=147910&hl=
2001 Pontiac Grand Prix GTP (Daily Driver)
2002 Discovery II SE7 (Wife's progeny wagon and tow vehicle)

Second place is S*** place , eh.  - Stéphane Peterhansel

#37 Fuze

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Posted 02 October 2017 - 12:50 PM

 mbruneaux, on 26 September 2017 - 07:41 AM, said:

Are you saying the "proper" or for the sake of longevity a pre-turbo MAF and a blow off valve would be best?  Is a blow off valve and boost controller the same thing?  I have a Lower Shores manual boost controller installed. Pardon my ignorance but I need to learn a lot more about the system.

I'm not really weighing in on pre or post turbo placement of the MAF sensor, that's a separate thing. The BOV allows pressure to escape the system when the throttle plate closes. Without it, the pressure backs up against the turbine, after enough times that pressure wave breaks the oil seals around the cold side of the turbo and oil leaks into the compressor housing, turning the car into a smoke machine.
The Boost controller simply delays the wastegate opening to allow more boost to build. The wastegate opens at the set pressure and the boost stops building as exhaust escapes though the wastegate, limiting turbo speed.

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