My N/A to Turbo swap. (Might as well try to organize and write this up)
08-18-2011, 10:45 AM
#76
08-18-2011, 10:59 AM
#77
Registered User
Thread Starter
Join Date: Apr 2011
Location: Raleigh, North Carolina
Posts: 75
And it runs from the vacuum canister.
The thing is, I think it is connected to the right port, but that valve opens for me around 2000RPM and I am not running the AC. And it makes a very annoying sound when it opens. (Think of a sound of a broken squeaky toy.)
Maybe I will just block it off for now.
By the way. That thread you linked to, where does the cruise control thing run to? I took my out a while ago, and I don't remember. I think the vacuum canister only has 3 port. The vacuum to intake manifold, the line to the AC system and the line to FICD. I am starting to worry I forgot a port somewhere.
Do you have any comments on what I am doing with the AFM?
08-18-2011, 01:36 PM
#78
Page 212 of the Haynes has the useful diagram. 
Also tons of vacuum diagrams in the FSM.
As for the AFM tuning, sounds good... I've never tried what you are doing, so I don't have any advice there, but the advice I can give is to buy / borrow a wideband a/f device if you are going to tune. The narrow band "sweeper" gauge that taps into your O2 sensor is really only good for knowing if it's rich or lean. A wide band will tell you exactly what it's doing all the time.
Some wide bands come w/ USB ports & you can use it on a comp for live data.
Also tons of vacuum diagrams in the FSM. As for the AFM tuning, sounds good... I've never tried what you are doing, so I don't have any advice there, but the advice I can give is to buy / borrow a wideband a/f device if you are going to tune. The narrow band "sweeper" gauge that taps into your O2 sensor is really only good for knowing if it's rich or lean. A wide band will tell you exactly what it's doing all the time.
Some wide bands come w/ USB ports & you can use it on a comp for live data.
09-02-2011, 01:22 PM
#79
Registered User
Thread Starter
Join Date: Apr 2011
Location: Raleigh, North Carolina
Posts: 75
I guess I should report on progress a little bit.
I ended up driving a full tank worth of miles on the car in the past two weeks, just to see how it performs.
The car got about 15MPG which is not a lot. I was not driving it very nicely, but I still know that it runs rich.
If I am driving about 70MPH the car does heat up. It does not overheat, but stabilises at 3/4 of of the temp gauge reading. I bought a new thermostat, and everything needed to flush the radiator, but have not gone through the process of cleaning it yet. Will see how it goes.
Another problem I ran into, is that when the engine is hot, it is hard to start it. The engine cranks up, then dies. I have to let it cool a bit, crank it for a while, and help it with the gas pedal. I ran into a local guy that works on these cars and he suggested that it is a common problem with the fuel rail. The fuel gets too hot, and bubbles form. His claim is that is why the engines had that weird fan going over the head cover. Of course I had removed mine. As of right now, my hope is that the cooler thermostat and a clean radiator should fix this.
I ended up driving a full tank worth of miles on the car in the past two weeks, just to see how it performs.
The car got about 15MPG which is not a lot. I was not driving it very nicely, but I still know that it runs rich.
If I am driving about 70MPH the car does heat up. It does not overheat, but stabilises at 3/4 of of the temp gauge reading. I bought a new thermostat, and everything needed to flush the radiator, but have not gone through the process of cleaning it yet. Will see how it goes.
Another problem I ran into, is that when the engine is hot, it is hard to start it. The engine cranks up, then dies. I have to let it cool a bit, crank it for a while, and help it with the gas pedal. I ran into a local guy that works on these cars and he suggested that it is a common problem with the fuel rail. The fuel gets too hot, and bubbles form. His claim is that is why the engines had that weird fan going over the head cover. Of course I had removed mine. As of right now, my hope is that the cooler thermostat and a clean radiator should fix this.
09-02-2011, 02:08 PM
#80
West Coast!
Join Date: Jul 2007
Location: Corona,CA
Posts: 1,956
it's called vapor lock and it happens to any car if you run it hard enough and it's true the gas bubbles in the fuel lines and then you don't get good atomization of fuel try letting your car idle for 2-3 mins before you turn it off. it's also good for letting the turbo oil cool so it dosen't cool in the hot side of the turbo.
09-02-2011, 03:59 PM
#81
Registered User
Thread Starter
Join Date: Apr 2011
Location: Raleigh, North Carolina
Posts: 75
it's called vapor lock and it happens to any car if you run it hard enough and it's true the gas bubbles in the fuel lines and then you don't get good atomization of fuel try letting your car idle for 2-3 mins before you turn it off. it's also good for letting the turbo oil cool so it dosen't cool in the hot side of the turbo.
I clearly have a thermostat that is set too high.
09-02-2011, 04:48 PM
#82
I doubt it's vapor lock (I always say this). Vapor lock is a big issue on carb's because the fuel pressure is 5-10psi. The Datsun EFI system pressure is 35psi (a lot of cars are even higher these days). It's not impossible, just not likely.
Who knows what it could be, as this is kind of a "Frankenstein" turbo build. Mix & match parts tend to cause problems.
I suggest double checking the CHTS, AFM, O2 Sensor, TPS, spark plug tips (gap and color / tip reading), and fuel injector spray.
The ignitor might be going out too (common "hard-hot-start" culprit).
EDIT... I just remembered you said you were trying to run low fuel pressure to compensate for bigger injectors... what's your current fuel pressure?
Who knows what it could be, as this is kind of a "Frankenstein" turbo build. Mix & match parts tend to cause problems.
I suggest double checking the CHTS, AFM, O2 Sensor, TPS, spark plug tips (gap and color / tip reading), and fuel injector spray.
The ignitor might be going out too (common "hard-hot-start" culprit).
EDIT... I just remembered you said you were trying to run low fuel pressure to compensate for bigger injectors... what's your current fuel pressure?
Last edited by NismoPick; 09-02-2011 at 04:52 PM.
09-02-2011, 07:12 PM
#83
Registered User
Thread Starter
Join Date: Apr 2011
Location: Raleigh, North Carolina
Posts: 75
I doubt it's vapor lock (I always say this). Vapor lock is a big issue on carb's because the fuel pressure is 5-10psi. The Datsun EFI system pressure is 35psi (a lot of cars are even higher these days). It's not impossible, just not likely.
Who knows what it could be, as this is kind of a "Frankenstein" turbo build. Mix & match parts tend to cause problems.
I suggest double checking the CHTS, AFM, O2 Sensor, TPS, spark plug tips (gap and color / tip reading), and fuel injector spray.
The ignitor might be going out too (common "hard-hot-start" culprit).
EDIT... I just remembered you said you were trying to run low fuel pressure to compensate for bigger injectors... what's your current fuel pressure?
Who knows what it could be, as this is kind of a "Frankenstein" turbo build. Mix & match parts tend to cause problems.
I suggest double checking the CHTS, AFM, O2 Sensor, TPS, spark plug tips (gap and color / tip reading), and fuel injector spray.
The ignitor might be going out too (common "hard-hot-start" culprit).
EDIT... I just remembered you said you were trying to run low fuel pressure to compensate for bigger injectors... what's your current fuel pressure?
I don't know if that matters or not. If I stop and start it quite quickly, I have no problem. If I let the car sit for 10min, then it is the worst. It would crank, start, then quickly loose RPM and stall. And at that point having my foot on the gas does absolutely nothing. I pretty much just need to open up the hood and let the car cool off. The fuel rail does get hot enough to where I don't want to touch it.
I messed the AFM when adjusting it, but it seems to work for now. Fuel injectors I checked too. I will check out the CHTS and the spark plugs when I get the chance.
By the way. Should I get a stable fuel pressure reading at all times, or is it okay that it fluctuates up and down especially at high RPMs? Basically, could my FPR be bad?
12-16-2011, 10:52 AM
#85
Registered User
Thread Starter
Join Date: Apr 2011
Location: Raleigh, North Carolina
Posts: 75
Okay. Time for an update because quite a lot of things happened since last time.
First of all, I wore out the tires I had on the car. And since it was still running on stock wheels, I got my self a new set of rims and tires.
They are 16x8 with zero offset. XXR2 wheels. And 225-50-16 tires.
Photos and fitment is below:
16x8 XXR 002 Rims+225/50R-16Tires vs Stock by ib042129, on Flickr
16x8 XXR 002 Rims+225/50R-16Tires Vs Stock 2 by ib042129, on Flickr
Front Gap 16x8 XXR 002 Rims+225/50R-16Tires by ib042129, on Flickr
I got an alignement afterwards and now the handling is phenomenal.
Now, on to the engine.
I ended up getting a wide-band gauge. I just could not make any meaningful adjustments without it.
The main issue was the timing. I thought that the engine has stock timing because when I bought the car, it was stock. It turns out that the timing was extremely retarded! Somebody before me must have messed with the distributor too much.
After I set the timing correctly, the car ran much smoother. No more gasoline smell from the exhaust, much faster throttle response. Much much smoother acceleration. The turbo does not kick in suddenly, but smoothly pushes you faster and faster until you reach full boost.
I ended up having to further adjust the AFM idle position AND the idle screw to get reasonably smooth and low idle.
I raised the fuel pressure up to close to 40psi, and played with the FMU a little.
The car runs at about the air/fuel mixture of 14 off boost, but under boost it goes to as low at 10.4 which is a little rich, I might back off on the FMU rate a little.
So it runs quite well now, but I should stil make small adjustment to the AFM and the FMU to fine tune it.
The only issue I have now it that at high RPM (above 4000) I start to lose boost. The boost gauge starts to creep down and settles at around 3PSI.
Any suggestion on what this could be?
New Look as of 2011/10/23 2 by ib042129, on Flickr
16x8 XXR 002 Rims+225/50R-16Tires Installed by ib042129, on Flickr
First of all, I wore out the tires I had on the car. And since it was still running on stock wheels, I got my self a new set of rims and tires.
They are 16x8 with zero offset. XXR2 wheels. And 225-50-16 tires.
Photos and fitment is below:
16x8 XXR 002 Rims+225/50R-16Tires vs Stock by ib042129, on Flickr
16x8 XXR 002 Rims+225/50R-16Tires Vs Stock 2 by ib042129, on Flickr
Front Gap 16x8 XXR 002 Rims+225/50R-16Tires by ib042129, on Flickr
I got an alignement afterwards and now the handling is phenomenal.
Now, on to the engine.
I ended up getting a wide-band gauge. I just could not make any meaningful adjustments without it.
The main issue was the timing. I thought that the engine has stock timing because when I bought the car, it was stock. It turns out that the timing was extremely retarded! Somebody before me must have messed with the distributor too much.
After I set the timing correctly, the car ran much smoother. No more gasoline smell from the exhaust, much faster throttle response. Much much smoother acceleration. The turbo does not kick in suddenly, but smoothly pushes you faster and faster until you reach full boost.
I ended up having to further adjust the AFM idle position AND the idle screw to get reasonably smooth and low idle.
I raised the fuel pressure up to close to 40psi, and played with the FMU a little.
The car runs at about the air/fuel mixture of 14 off boost, but under boost it goes to as low at 10.4 which is a little rich, I might back off on the FMU rate a little.
So it runs quite well now, but I should stil make small adjustment to the AFM and the FMU to fine tune it.
The only issue I have now it that at high RPM (above 4000) I start to lose boost. The boost gauge starts to creep down and settles at around 3PSI.
Any suggestion on what this could be?
New Look as of 2011/10/23 2 by ib042129, on Flickr
16x8 XXR 002 Rims+225/50R-16Tires Installed by ib042129, on Flickr
12-17-2011, 03:32 PM
#86
Mr Z++ Wiki
Join Date: Sep 2009
Location: Victoria, BC
Posts: 2,195
Okay. Time for an update because quite a lot of things happened since last time.
................
I got an alignement afterwards and now the handling is phenomenal.
Now, on to the engine.
I ended up getting a wide-band gauge. I just could not make any meaningful adjustments without it.
The main issue was the timing. I thought that the engine has stock timing because when I bought the car, it was stock. It turns out that the timing was extremely retarded! Somebody before me must have messed with the distributor too much.
After I set the timing correctly, the car ran much smoother. No more gasoline smell from the exhaust, much faster throttle response. Much much smoother acceleration. The turbo does not kick in suddenly, but smoothly pushes you faster and faster until you reach full boost.
I ended up having to further adjust the AFM idle position AND the idle screw to get reasonably smooth and low idle.
I raised the fuel pressure up to close to 40psi, and played with the FMU a little.
The car runs at about the air/fuel mixture of 14 off boost, but under boost it goes to as low at 10.4 which is a little rich, I might back off on the FMU rate a little.
So it runs quite well now, but I should stil make small adjustment to the AFM and the FMU to fine tune it.
The only issue I have now it that at high RPM (above 4000) I start to lose boost. The boost gauge starts to creep down and settles at around 3PSI.
Any suggestion on what this could be?
................
I got an alignement afterwards and now the handling is phenomenal.
Now, on to the engine.
I ended up getting a wide-band gauge. I just could not make any meaningful adjustments without it.
The main issue was the timing. I thought that the engine has stock timing because when I bought the car, it was stock. It turns out that the timing was extremely retarded! Somebody before me must have messed with the distributor too much.
After I set the timing correctly, the car ran much smoother. No more gasoline smell from the exhaust, much faster throttle response. Much much smoother acceleration. The turbo does not kick in suddenly, but smoothly pushes you faster and faster until you reach full boost.
I ended up having to further adjust the AFM idle position AND the idle screw to get reasonably smooth and low idle.
I raised the fuel pressure up to close to 40psi, and played with the FMU a little.
The car runs at about the air/fuel mixture of 14 off boost, but under boost it goes to as low at 10.4 which is a little rich, I might back off on the FMU rate a little.
So it runs quite well now, but I should stil make small adjustment to the AFM and the FMU to fine tune it.
The only issue I have now it that at high RPM (above 4000) I start to lose boost. The boost gauge starts to creep down and settles at around 3PSI.
Any suggestion on what this could be?
You should really think about running MegaSquirt if you are playing with AFRs. You can more precisely tune your spark and fuel. With the AFM and FMU you will always have to comprimise for the best spot on part of the map but sacrifice elsewhere. With MS you can adjust on a 16 x 16 map. You will also be able to run lean at cruise and increase your fuel economy AND performance. 10.4 is pretty rich - if you are running an intercooler and under 10lbs of boost you shouldn't need much more than an AFR of 12.
12-18-2011, 02:53 PM
#87
Registered User
Thread Starter
Join Date: Apr 2011
Location: Raleigh, North Carolina
Posts: 75
Nice progress. It's common for guys to go back to the small block chevy they grew up with and set the idle for the turbo at 10 deg which is way off. For the boost issue are you running an aftermarket gauge?
You should really think about running MegaSquirt if you are playing with AFRs. You can more precisely tune your spark and fuel. With the AFM and FMU you will always have to comprimise for the best spot on part of the map but sacrifice elsewhere. With MS you can adjust on a 16 x 16 map. You will also be able to run lean at cruise and increase your fuel economy AND performance. 10.4 is pretty rich - if you are running an intercooler and under 10lbs of boost you shouldn't need much more than an AFR of 12.
You should really think about running MegaSquirt if you are playing with AFRs. You can more precisely tune your spark and fuel. With the AFM and FMU you will always have to comprimise for the best spot on part of the map but sacrifice elsewhere. With MS you can adjust on a 16 x 16 map. You will also be able to run lean at cruise and increase your fuel economy AND performance. 10.4 is pretty rich - if you are running an intercooler and under 10lbs of boost you shouldn't need much more than an AFR of 12.
I was thinking, is it possible that with all the extra pipes due to the intercooler the wastegate opens too early and the turbo simply can't keep the pressure up with the extra flow?
I am contemplating connecting the wastegate to either the pipe right before the throttle body, or to a port in the intake manifold instead of the turbo outlet. That way it is referenced to the pressure at the manifold.
Any obvious problems with doing this?
Yes, I know MegaSquirt is great. I will get to it eventually, but I want to play with it as is for now.
12-18-2011, 04:30 PM
#88
I have Maximum Boost in PDF if you want it (it's ~50MB).
12-18-2011, 04:56 PM
#89
Registered User
Thread Starter
Join Date: Apr 2011
Location: Raleigh, North Carolina
Posts: 75
The reason that I mentioned it here is because I read it from atlanticz
http://www.atlanticz.ca/zclub/techtips/turbo/index.html
I would be more than happy if you give me the PDF of that book.
A far at the leak goes. That turbo is the stock 280zxt turbo. No boost controller.
I might have a leaky BOV though. I will try pinching the BOV hose off and see what happens.
If you remove the sensing line for the turbo, and put it to the stock manifold you will notice the boost off lift-throttle works much better, as when you slam the throttle shut, the vacuum of the manifold closes the waste gate actuator much faster, and holds it closed tighter during cruise, making for good boost response.
I would be more than happy if you give me the PDF of that book.
A far at the leak goes. That turbo is the stock 280zxt turbo. No boost controller.
I might have a leaky BOV though. I will try pinching the BOV hose off and see what happens.
12-19-2011, 01:24 PM
#92
Registered User
Thread Starter
Join Date: Apr 2011
Location: Raleigh, North Carolina
Posts: 75
So. Yesterday, I pinched off the BOV and I still had the same problem.
If it is a leak, wouldn't it be a big leak if I am loosing 3PSI? I would thinks
I would have noticed that big of a vacuum leak at cruise/idle.
I checked the wastegate a while ago and the spring-load seemed to be solid.
Besides checking the spring and any play in the rod that connects to the valve, how would I check the wastegate.
The cat, and and the exhaust pipes after it (except for the muffler) are stock N/A pipes. Could they be causing too much back pressure?
If it is a leak, wouldn't it be a big leak if I am loosing 3PSI? I would thinks
I would have noticed that big of a vacuum leak at cruise/idle.
I checked the wastegate a while ago and the spring-load seemed to be solid.
Besides checking the spring and any play in the rod that connects to the valve, how would I check the wastegate.
The cat, and and the exhaust pipes after it (except for the muffler) are stock N/A pipes. Could they be causing too much back pressure?
12-19-2011, 03:11 PM
#93
Pinched off the BOV? What did you "pinch off" ? And how is "pinching off" anything going to stop a leak unless you clamped the hell outta it?
A vacuum leak and a boost leak are two different things... remember one is negative pressure, one is positive pressure. Couplers and vacuum lines will act differently between those pressures... (i.e. a coupler may expand / leak under boost, and hold tight under vacuum). I actually had that exact problem when I test ran my car as I was using sewer line couplers to mock up the IC... one kept blowing off at full boost.
You should check the waste gate by putting +pressure on it and holding it at that pressure to watch for a leak down. You can get a hand held pump for cheap:
A vacuum leak and a boost leak are two different things... remember one is negative pressure, one is positive pressure. Couplers and vacuum lines will act differently between those pressures... (i.e. a coupler may expand / leak under boost, and hold tight under vacuum). I actually had that exact problem when I test ran my car as I was using sewer line couplers to mock up the IC... one kept blowing off at full boost.
You should check the waste gate by putting +pressure on it and holding it at that pressure to watch for a leak down. You can get a hand held pump for cheap:
01-08-2012, 02:04 PM
#94
Registered User
Thread Starter
Join Date: Apr 2011
Location: Raleigh, North Carolina
Posts: 75
Pinched off the BOV? What did you "pinch off" ? And how is "pinching off" anything going to stop a leak unless you clamped the hell outta it?
A vacuum leak and a boost leak are two different things... remember one is negative pressure, one is positive pressure. Couplers and vacuum lines will act differently between those pressures... (i.e. a coupler may expand / leak under boost, and hold tight under vacuum). I actually had that exact problem when I test ran my car as I was using sewer line couplers to mock up the IC... one kept blowing off at full boost.
A vacuum leak and a boost leak are two different things... remember one is negative pressure, one is positive pressure. Couplers and vacuum lines will act differently between those pressures... (i.e. a coupler may expand / leak under boost, and hold tight under vacuum). I actually had that exact problem when I test ran my car as I was using sewer line couplers to mock up the IC... one kept blowing off at full boost.
By "pinching off" I did mean I clamped the **** out of the BOV outlet hose so is the BOV does leak, the air has nowhere to go. And of couse that did not help.
I double checked all my couplers and they are all solid. I even replaced one that might have been iffy. (The coupler from the Turbo to the J-pipe.)
This again did not solve the problem. I simply can't find a leak as of yet.
One concern maybe is the EGR. I kept it as is. Could the thing open at wide open throttle under boost? If it does, it might cause the leak. Right?
(Simply disconnecting the EGR vacuum line did nothing.)
The other thing is the BCDD valve. I have to leave it disconnected because otherwise the idle is too high. It seems that there is no way air could escape through it though. No connection to the outside.
Suggestions?
Thread
Thread Starter
Forum
Replies
Last Post
kdxzx
300ZX (Z31) Performance / Technical
1
10-24-2010 01:20 PM
johnsonsz31tt
300ZX (Z31) Forums
93
05-07-2008 07:27 PM
Turbo86
300ZX (Z31) Performance / Technical
2
07-27-2006 05:38 PM
Bookmarks
