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~73 Turbo L28 to N/A RB25 240z Project~


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Just waiting on a few odds and ends then I'll be putting everything back together. Hopefully in a week or so Ill be up and running.

 

I'll be using this in-line radiator hose piece for my water return into the upper radiator hose. Cheaper, faster and easier than finding another thermostat housing.

 

IMG_6608_zps8e2baf05.jpg

Edited by ~KnuckleDuster~
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You're likely going to have cooling stability issues doing that, if you're doing what I think you're doing, you're effectively bypassing the thermostat. It will take longer for the engine to warm up, and it may never actually stabilize. 

You need to return any coolant to the lower half of the thermostat housing in order to have a properly functioning cooling system.

 

What is it that you're wanting to plumb into this fitting? 

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You're likely going to have cooling stability issues doing that, if you're doing what I think you're doing, you're effectively bypassing the thermostat. It will take longer for the engine to warm up, and it may never actually stabilize. 

 

You need to return any coolant to the lower half of the thermostat housing in order to have a properly functioning cooling system.

 

What is it that you're wanting to plumb into this fitting? 

I wanted to have the coolant exiting the turbo returning into this.

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I assume you will be feeding the turbo from the heater core feed?

 

I would do it one of two ways:

 

Either run it in series with the heater core, this way requires running hose back and forth behind the engine, but can work.

 

The other way I would do it is to T into one of the lines feeding the thermostat housing now, for the return.

 

I would also study how Nissan did it originally. I'm using a non water cooled turbo on my car, so I didn't need to worry about this, but back when I built a turbo V6 for my Jimmy, I T-ed into the heater core feed for the turbo feed and then returned the turbo coolant back to a fitting below the thermostat. This worked very well.

 

Looking at the turbo supplement for the 1981 Turbo ZX, available an xenons130.com, it looks like the turbo coolant is fed from the hose at the back of the lower rad hose inlet, that also attaches to the heater core, and then returned to the thermostat housing below the thermostat.

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I assume you will be feeding the turbo from the heater core feed?

 

I would do it one of two ways:

 

Either run it in series with the heater core, this way requires running hose back and forth behind the engine, but can work.

 

The other way I would do it is to T into one of the lines feeding the thermostat housing now, for the return.

 

I would also study how Nissan did it originally. I'm using a non water cooled turbo on my car, so I didn't need to worry about this, but back when I built a turbo V6 for my Jimmy, I T-ed into the heater core feed for the turbo feed and then returned the turbo coolant back to a fitting below the thermostat. This worked very well.

 

Looking at the turbo supplement for the 1981 Turbo ZX, available an xenons130.com, it looks like the turbo coolant is fed from the hose at the back of the lower rad hose inlet, that also attaches to the heater core, and then returned to the thermostat housing below the thermostat.

 

Correct feed will be from heater core line. I would normally run the return into the heater core return line but I've read about the cooling issues in the back of the head and plumbing more boiling coolant back there would be counter productive.

 

I was just looking for a quick solution since my T stat housing is non ZX and has a lack of ports to plumb into. Looks like I have a new scavenger hunt on my hands finding the T stat unit from a ZX. Thanks for your input, the last thing I want to do is rush some of these last details.

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Looking at the turbo supplement for the 1981 Turbo ZX, available an xenons130.com, it looks like the turbo coolant is fed from the hose at the back of the lower rad hose inlet, that also attaches to the heater core, and then returned to the thermostat housing below the thermostat.

 

 

L28ET's were oil cooled only. I don't believe they added water cooling until the Z31?

 

 

Correct feed will be from heater core line. I would normally run the return into the heater core return line but I've read about the cooling issues in the back of the head and plumbing more boiling coolant back there would be counter productive.

 

I was just looking for a quick solution since my T stat housing is non ZX and has a lack of ports to plumb into. Looks like I have a new scavenger hunt on my hands finding the T stat unit from a ZX. Thanks for your input, the last thing I want to do is rush some of these last details.

 

The heater core feed is from the back of the head, and the return goes to the fitting on the lower rad hose inlet to the water pump. I've run my turbo coolant source from the lower thermostat housing, through the turbo and into the heater core return to the the water pump. I've run it like that for over 10 years. No overheating issues.

 

Nigel

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The heater core feed is from the back of the head, and the return goes to the fitting on the lower rad hose inlet to the water pump. I've run my turbo coolant source from the lower thermostat housing, through the turbo and into the heater core return to the the water pump. I've run it like that for over 10 years. No overheating issues.

 

Nigel

 

 

For some reason I was thinking the feed was lower rad hose / heater line and return was t stat. I must have somehow got them reversed. I even researched it and thought Tony D said that was the case, but I re-checked and your correct the feed should be from the t stat going through the turbo and into back into the lower rad hose. I had the sources right but my direction of flow somehow got mixed up! :bonk:

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Well so far time has been spent mocking things up and waiting for parts to arrive.

 

Removed the old thermostat housing in preparation for the new ZX unit. Looks like the thermostat was due for a change no?

 

IMG_6637_zpsf1afb9cf.jpg

 

The turbo had to be clocked so that the compressor outlet wouldn't contact the intake manifold. The only downside to this is I have to buy an aftermarket wastegate now which is going to cost me around $100. The good thing is I can choose the boost level, it's set at via spring selection. I'm going to have it set at 7.35 to be on the safe side, the next one up is 11.7 and I don't want to max out my injectors right off the bat so I'm going to play it safe. I can always get a MBC later on down the road.

 

IMG_6639_zpsa2215467.jpg

 

An ongoing pain in my ass has been where to stuff the mass airflow sensor and filter. It's very tight due to the intercooler pipes both being on the left side and trying to run the air filter down low leaving it nearly scraping the ground. So I finally got my hands on a stock ZX turbo afm to turbo pipe and cut it down to fit. Had to cut approx 4 inches off. Much better than the assortment of pipe and couplers on the last turbo.

 

IMG_6643_zpsd6d58551.jpg.

 

IMG_6644_zps86694b09.jpg

Edited by ~KnuckleDuster~
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I was gonna send you a picture of my cars setup to show you how the piping is done on it with MAF, when I realized mine has no MAF. I'm new to the S30 game and still trying to figure out what somebody did to my car. It appears to be a giant mishmash and I wish somebody had documented it somewhere. So now im stuck guessing. lol.

 

Your project looks great, and I think guys on here are taking advantage of how great it is that you have documented every step of the way. I applaud your efforts in making sure you keep the community involved in your projects developments and hope I can document my project half as well as you have!

 

Keep up the awesome.

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I was gonna send you a picture of my cars setup to show you how the piping is done on it with MAF, when I realized mine has no MAF. I'm new to the S30 game and still trying to figure out what somebody did to my car. It appears to be a giant mishmash and I wish somebody had documented it somewhere. So now im stuck guessing. lol.

 

Your project looks great, and I think guys on here are taking advantage of how great it is that you have documented every step of the way. I applaud your efforts in making sure you keep the community involved in your projects developments and hope I can document my project half as well as you have!

 

Keep up the awesome.

Thanks! It's posts like yours that motivate me to stay on top of it. :cheers:

 

It seems like your in almost the same situation I was in when I got this 73. Mismatched parts and poorly executed mods and or repairs. At some point you have to decide to go on trying to fix everything or just buy a different motor or car for that matter. If you do plan on fixing what you have be prepared to spend some money and do a lot of research. You will acquire a larger love for your car this way but if your impatient or lack the funds you may be better off swapping the motor. I'll keep and eye on your build thread and try to help where I can.

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If you can get the air filter right out of the engine bay that will drop your intake temps significantly. I had my air filter in almost the exact same spot as you for a long time, back before I built and installed my IC. I don't recall the actual intake temp numbers but I do remember that moving the air filter outside of the engine bay dropped my intake temps by about 20* F.

 

For some reason this is the only picture I can find of where my filter is now.

post-3537-0-64186700-1398547332_thumb.jpg

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If you can get the air filter right out of the engine bay that will drop your intake temps significantly. I had my air filter in almost the exact same spot as you for a long time, back before I built and installed my IC. I don't recall the actual intake temp numbers but I do remember that moving the air filter outside of the engine bay dropped my intake temps by about 20* F.

 

For some reason this is the only picture I can find of where my filter is now.

Yeah I need a perfectly bent pipe like yours hehe. I may just fashion up an air duct and ram some cooler air into the filter for a temporary thing.

 

I was playing around with some longer piping like that with my previous set-up and noticed the longer the piping got the more laggy it felt. You didn't notice any lag with that long pipe?

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Yeah I need a perfectly bent pipe like yours hehe. I may just fashion up an air duct and ram some cooler air into the filter for a temporary thing.

 

I was playing around with some longer piping like that with my previous set-up and noticed the longer the piping got the more laggy it felt. You didn't notice any lag with that long pipe?

 

Maybe a slight increase in "lag", but nothing too noticeable. I'm using 3" for that inlet, and my turbo is on the large side (6.5L diesel turbo), so it's "laggy" to start with. 

 

I know the set-up is not ideal, but I'd rather have the slight increase in lag, and cooler intake temps, where my IC doesn't have to pull as much heat out of the charge. My IC's working pretty hard as it is, before I put in the IC, intake temps at lower boost levels was upwards of 180*, now when in boost at higher levels it's damn near ambient, usually only a few degrees above I need to add a pre-IC temp sensor to see just how effective/efficient the IC is.

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