E24 Turbo Build
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TurboShark
- Posts: 53
- Joined: Aug 22, 2013 2:19 PM
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TurboShark
- Posts: 53
- Joined: Aug 22, 2013 2:19 PM
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TurboShark
- Posts: 53
- Joined: Aug 22, 2013 2:19 PM
So here’s some theory that I pieced together after doing quite a bit of reading up on Turbo systems to figure out what made sense in the placement of the intake system components and why it made sense. Then I looked for photos of different factory turbo systems and found that almost all simple factory turbo systems follow the same basic layout:
Filter => AFM/MAF => Turbo => Intercooler => Blow-off => Idle-Valve => Throttle-Body
The Blow-Off valve can be almost anywhere in the charge pipes but it should dump back into the intake system between the AFM/MAF and the Turbo intake. This is done to recirculate the already computer-measured intake air back into the system without the computer re-calculating the same air flow twice and over adding fuel at the injectors. It’s slamming the TB shut that drives up the charge pressure and pops the blow-off open. The purpose is to dump the over-pressure air before it overloads the turbo (bearings I believe) while the turbo has not yet seen reduced exhaust pressure from closing the TB
The Idle-Valve is to take the computer-measured intake air and pass it into the manifold bypassing the throttle body which is basically closed at idle time
Crankcase vent (from the valve cover) can also be passed to the intake between AFM/MAF and the Turbo. This is to stop the charge air getting into the crankcase backwards through the valve cover vent pipe.
The gas fume vent pipe from the carbon filter should also be passed into the intake between AFM/MAF and the Turbo. I’m surmising here but if the carbon filter vent is connected into the charge pipe (as you have) then the charge air can go back through the vent system an into the gas tank. That could be interesting
The above is how I set up my system which I have not yet finished so that’s why I stated “theory”. I did it this way as a result of the reading and picture/diagram hunting and wanting to stay a little bit eco-friendly. I also noticed many non-factory setups that do the following:
• Dump the blow-off air into the atmosphere. This may result in little explosions out the tail-pipe as that dumped volume of air is not passed into the engine but the computer pumps in the gas at the injectors expecting that dumped air (AFM/MAF input tells it to do so) which as a result over richens the mixture
• The crankcase vent is often vented to the atmosphere or passed into the exhaust manifold after the turbo
I tried to get the above validated on this forum but nobody has answered
This isn’t a very good photo but it shows the e23 745 turbo setup and it follows the same basic pattern of intake assembly http://us1.webpublications.com.au/stati ... 50_4lo.jpg
AFM is before the Turbo air intake.
Hope this helps
Filter => AFM/MAF => Turbo => Intercooler => Blow-off => Idle-Valve => Throttle-Body
The Blow-Off valve can be almost anywhere in the charge pipes but it should dump back into the intake system between the AFM/MAF and the Turbo intake. This is done to recirculate the already computer-measured intake air back into the system without the computer re-calculating the same air flow twice and over adding fuel at the injectors. It’s slamming the TB shut that drives up the charge pressure and pops the blow-off open. The purpose is to dump the over-pressure air before it overloads the turbo (bearings I believe) while the turbo has not yet seen reduced exhaust pressure from closing the TB
The Idle-Valve is to take the computer-measured intake air and pass it into the manifold bypassing the throttle body which is basically closed at idle time
Crankcase vent (from the valve cover) can also be passed to the intake between AFM/MAF and the Turbo. This is to stop the charge air getting into the crankcase backwards through the valve cover vent pipe.
The gas fume vent pipe from the carbon filter should also be passed into the intake between AFM/MAF and the Turbo. I’m surmising here but if the carbon filter vent is connected into the charge pipe (as you have) then the charge air can go back through the vent system an into the gas tank. That could be interesting
The above is how I set up my system which I have not yet finished so that’s why I stated “theory”. I did it this way as a result of the reading and picture/diagram hunting and wanting to stay a little bit eco-friendly. I also noticed many non-factory setups that do the following:
• Dump the blow-off air into the atmosphere. This may result in little explosions out the tail-pipe as that dumped volume of air is not passed into the engine but the computer pumps in the gas at the injectors expecting that dumped air (AFM/MAF input tells it to do so) which as a result over richens the mixture
• The crankcase vent is often vented to the atmosphere or passed into the exhaust manifold after the turbo
I tried to get the above validated on this forum but nobody has answered
This isn’t a very good photo but it shows the e23 745 turbo setup and it follows the same basic pattern of intake assembly http://us1.webpublications.com.au/stati ... 50_4lo.jpg
AFM is before the Turbo air intake.
Hope this helps
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TurboShark
- Posts: 53
- Joined: Aug 22, 2013 2:19 PM
I thought putting the AFM right before the TB would be fine. It makes sense that metering the air and how much is getting taken in right before the last possible point (TB) throughout all the charge piping and everything makes sense. I hope I don't have to put it in front of the turbo because then I would have to make a new manifold.
Can somebody else chime in here whether the AFM should be ok right before the TB or that it should be before the turbo.
Thanks for the input!
Can somebody else chime in here whether the AFM should be ok right before the TB or that it should be before the turbo.
I'm not sure where you saw that I have the vent pipe connected to my charge piping but I don't, or at least I don't think I do!rwpg wrote: The gas fume vent pipe from the carbon filter should also be passed into the intake between AFM/MAF and the Turbo. I’m surmising here but if the carbon filter vent is connected into the charge pipe (as you have) then the charge air can go back through the vent system an into the gas tank. That could be interesting
Thanks for the input!
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TurboShark
- Posts: 53
- Joined: Aug 22, 2013 2:19 PM
Well I fired up the engine today to try to get it idling well enough and good enough throttle response to try to go test drive it to start tuning the FMU and found the car smoking like crazy (white smoke 
). Pulled the dipstick and it was a very low viscosity (like coolant had diluted the oil) and it looked a little milky.
So it's pretty obvious that it is the head gasket. How in the hell would I blow a head gasket without even driving it? Revving it up while trying to tune it would blow a head gasket?
Anyway, going to order an MLS and ARP studs and get at it. What size MLS would you guys recommend for my application?
). Pulled the dipstick and it was a very low viscosity (like coolant had diluted the oil) and it looked a little milky. So it's pretty obvious that it is the head gasket. How in the hell would I blow a head gasket without even driving it? Revving it up while trying to tune it would blow a head gasket?
Anyway, going to order an MLS and ARP studs and get at it. What size MLS would you guys recommend for my application?
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mooseheadm5
- Beamter
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Here’s what I saw in your pictures. Assuming you have things installed in a standard configuration, the valve at the red arrow is the carbon filter vent valve that lets the gas fumes into the intake. You have this valve in the charge pipe between the Turbo and the Throttle Body (TB)
That valve works off a temperature driven bypass valve that’s mounted in the thermostat housing and it activates a vacuum line (small hose). The gas fume feed line (large hose) connects to the carbon filter to pass the gas fumes from the tank into the intake system and burn them up when the engine is running. I can’t remember if the valve is open when the engine is cold or open when it’s hot. Either way, I’m guessing the turbo boost pressure will run down that large line and back into the carbon filter, then into the tank through the vent system. I would take that carbon filter feed valve out of the charged intake pipes and move it to the intake before the Turbo compresses the air.
On the AFM position: you can probably get away with the AFM where it is and take all the other hoses out of the charge pipes except the Blow-Off and the idle valve between the AFM and the Throttle Body. All other hoses should connect to the system before the Turbo intake. If you can’t do that then you may want to run them into the air filter or vent them to atmosphere
That valve works off a temperature driven bypass valve that’s mounted in the thermostat housing and it activates a vacuum line (small hose). The gas fume feed line (large hose) connects to the carbon filter to pass the gas fumes from the tank into the intake system and burn them up when the engine is running. I can’t remember if the valve is open when the engine is cold or open when it’s hot. Either way, I’m guessing the turbo boost pressure will run down that large line and back into the carbon filter, then into the tank through the vent system. I would take that carbon filter feed valve out of the charged intake pipes and move it to the intake before the Turbo compresses the air.
On the AFM position: you can probably get away with the AFM where it is and take all the other hoses out of the charge pipes except the Blow-Off and the idle valve between the AFM and the Throttle Body. All other hoses should connect to the system before the Turbo intake. If you can’t do that then you may want to run them into the air filter or vent them to atmosphere
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TurboShark
- Posts: 53
- Joined: Aug 22, 2013 2:19 PM
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TurboShark
- Posts: 53
- Joined: Aug 22, 2013 2:19 PM
There is a small vacuum line that is connected to a larger (3/4") vacuum line that connects the valve cover vent to the intake. I believe in that picture the smaller line is connected to the intake. It could be from the green valve on top of the thermostat housing though. There are two vacuum lines coming off that, one has a restrictor on the end and the other is connected to vacuum if I recall correctly. So you are saying put it in the intake, but after the throttle body? There is one place I know to tap into, which is on the driver's side on the bottom of the intake, there is a port that dumps. Connect it to that? I was planning on running the vacuum line from my BEGi 2025 to that port, but I guess I could run a T fitting?rwpg wrote:That valve works off a temperature driven bypass valve that’s mounted in the thermostat housing and it activates a vacuum line (small hose). The gas fume feed line (large hose) connects to the carbon filter to pass the gas fumes from the tank into the intake system and burn them up when the engine is running. I can’t remember if the valve is open when the engine is cold or open when it’s hot. Either way, I’m guessing the turbo boost pressure will run down that large line and back into the carbon filter, then into the tank through the vent system. I would take that carbon filter feed valve out of the charged intake pipes and move it to the intake before the Turbo compresses the air.
On the AFM position: you can probably get away with the AFM where it is and take all the other hoses out of the charge pipes except the Blow-Off and the idle valve between the AFM and the Throttle Body. All other hoses should connect to the system before the Turbo intake. If you can’t do that then you may want to run them into the air filter or vent them to atmosphere
The vacuum line from the valve at the red arrow should go to the green valve in the thermostat housing. The other side of that green valve should go to the manifold for vacuum
The large outlet pipe of the valve at the red arrow that is plugged into the intake boot just before the AFM: that should be plugged into the intake after the air filter and before the turbo. Put it into the non-pressure side of the intake system.
The large outlet pipe of the valve at the red arrow that is plugged into the intake boot just before the AFM: that should be plugged into the intake after the air filter and before the turbo. Put it into the non-pressure side of the intake system.
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TurboShark
- Posts: 53
- Joined: Aug 22, 2013 2:19 PM
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mooseheadm5
- Beamter
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- Joined: Apr 08, 2009 10:30 PM
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TurboShark
- Posts: 53
- Joined: Aug 22, 2013 2:19 PM
Wellll it's finally driving!
Ended up my turbo that I got from the junkyard had bad seals. Oil was burning like crazy, that was the smoke I was getting. Got a new one and got vacuum lines hooked up correctly and drove it all day today. Got some long stretch of road and got to tune it a little bit. I'm at about 15-16 idling (can bring it down a tiny bit) 13-15 around town and when I get into the boost it goes down to about 12, although I have seen it dip to 10. I didn't get to do much of it tonight, I'll continue it this week.
I really jumped into this whole turbo setup and I couldn't have done it without the help of the members on the board, thanks guys.
Next on the list is mount my gauges correctly, not just them laying on the seat, and then lower it!
Ended up my turbo that I got from the junkyard had bad seals. Oil was burning like crazy, that was the smoke I was getting. Got a new one and got vacuum lines hooked up correctly and drove it all day today. Got some long stretch of road and got to tune it a little bit. I'm at about 15-16 idling (can bring it down a tiny bit) 13-15 around town and when I get into the boost it goes down to about 12, although I have seen it dip to 10. I didn't get to do much of it tonight, I'll continue it this week.
I really jumped into this whole turbo setup and I couldn't have done it without the help of the members on the board, thanks guys.
Next on the list is mount my gauges correctly, not just them laying on the seat, and then lower it!
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TurboShark
- Posts: 53
- Joined: Aug 22, 2013 2:19 PM
Mounted my boost gauge and AFM where the ashtray used to be
Turned out pretty good.
Anyway, I have been dying to lower it so I ordered some JDM coilover sleeves to start on the DIY coilover project. Going to make a skidplate first to keep me from bashing the oil pan in but after that it's AWN!
Also quick question for the BEGi tuning guys: I still am pretty rich at full throttle, like around 10.5-11. I added the restrictor inline and backed the center screw out even more (it is pretty damn close to falling out it's so backed out) and it's still rich. Any other options I have?
Turned out pretty good.
Anyway, I have been dying to lower it so I ordered some JDM coilover sleeves to start on the DIY coilover project. Going to make a skidplate first to keep me from bashing the oil pan in but after that it's AWN!
Also quick question for the BEGi tuning guys: I still am pretty rich at full throttle, like around 10.5-11. I added the restrictor inline and backed the center screw out even more (it is pretty damn close to falling out it's so backed out) and it's still rich. Any other options I have?
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TurboShark
- Posts: 53
- Joined: Aug 22, 2013 2:19 PM
Also, I noticed I wasn't building full boost through the gears (wastegated at 13psi, was only getting up to about 6). I took the line from the compressor housing to the wastegate off and plugged it to see if the wastegate was the culprit, and I am building more boost. Anybody have any ideas as to why it would be opening prematurely or anything?
Re:
Good morning. where did you purchase you Begi RRFPR and you TCD chip?TurboShark wrote:Already have the BEGi 2025 and the TCD chip. Only downside to the AFM is its so damn big. Having to put that, the vent to the valve cover and the (what I'm guessing) the idle air control valve in line of all the intercooler piping will be a task but shouldn't be too bad.