Coolant expansion tank for DE APS twin turbo
10-22-2012, 08:54 PM
#1
Coolant expansion tank for DE APS twin turbo
I have about had it with the cooling system problems with my car. I have been boosted for over 7 yrs now, and one constant headache has been the cooling system. Just look at the number of people here having cooling issues. Sure the system is PITA to bleed, but that is kind of the point to my informative rant.... and for inquiring minds I got a big koyo, but that isn't cutting it.
I don't drive my car a ton, but every once in a while when I do, I get some coolant pushing.....oh, noes, head lift, bad head gasket, warped heads, one would think.... but this pollock doesn't think so. Motor has been strong for about 5 yrs now ('07 build) with L19's and hks stoppers. I have a trusted mechanic, so I am confident he put the thing together correctly. But lately the thing has been a bear.
so I set out to figure this SOB out once and for all. I won't waste your time on ALL of my thought process, but here is most of it.
The APS system boils the coolant coming off the turbos. I found after a fresh bleed/fill procedure I would get some coolant pushing, but here's the thing.... it was very minimal during driving. Sure the coolant got hot (200 degrees) and expanded and pushed into the overflow, but that's normal. It would maybe fill it 1/2 full. Mind you the aps supplied overflow is MUCH too small, so the amount of expansion seems like a lot.
So now I continue to drive the car hard and come to an idle with little cool down driving and let the car sit, still running mind you. I would lose heat for a short time, bring the revs up a bit, and the heat would come back, but a nice coolant spout would shoot from the overflow. The turbos are creating a localized hot spot in the system and boiling the coolant most notable under two conditions
1.) hard driving followed by a quick idle session
2.) hard driving followed by a quick shut down.
****but any spirited driving could induce a localized hotspot which would introduce air into the system the way it comes from the factory
The coolant travels from the LHS of the motor through LHS turbo, under the motor to RHS turbo, then back up by the stock bleeder... this is just too much for the system. Now I have boiled coolant being fed back into the system with now where for the air to go. Usually I find it gets stuck by the stat or back in the heater core. Once we get air in the system, it's a nasty downward spiral to overheating.
So now I am hitting the web to figure out what I can do about this. I come across terms like surge tank, expansion tank, overflow tank, header tank, breather tanks. Surge/expansion/header/breather are kind of used interchangably, but are different from an overflow. what it comes down to is the fact that our fill and header tank is not the highest point in the system. We need to change that. Look at the GTR coolant system. They have a dedicated expansion tank... basically fully redesigned coolant system. that system is what we need to retrofit into our DE setups.
I came across VERY limited talk about surge tanks/expansion tanks on this forum, but I did come across one. of ALL the issues with the DE system, we have, for the most part ONE person that isn't completely clueless? I did later find some SGP cars with breathers, but nobody said boo about them.
I am in the process of trying to find a suitable expansion tank to fit the limited space I have in the engine bay. djtimodj's design in the link above is what I am going for, except I want directly run the feed off the turbo into the tank without splicing in silicone hose. I have a few more things in the way with the APS big fuel system, so fitment is very challenging. I am thinking of having a custom one made locally to fit the area......
the reason I post this before I have fitted mine is to see if anyone has insight into some custom tanks before I head to a local fabricator?
I know I didn't cover everything so if people have questions, post them up and I'll do my best to answer them. I have been working on this the past 10 days and done a lot of troubleshooting, bleeding, testing on my system.
I don't drive my car a ton, but every once in a while when I do, I get some coolant pushing.....oh, noes, head lift, bad head gasket, warped heads, one would think.... but this pollock doesn't think so. Motor has been strong for about 5 yrs now ('07 build) with L19's and hks stoppers. I have a trusted mechanic, so I am confident he put the thing together correctly. But lately the thing has been a bear.
so I set out to figure this SOB out once and for all. I won't waste your time on ALL of my thought process, but here is most of it.
The APS system boils the coolant coming off the turbos. I found after a fresh bleed/fill procedure I would get some coolant pushing, but here's the thing.... it was very minimal during driving. Sure the coolant got hot (200 degrees) and expanded and pushed into the overflow, but that's normal. It would maybe fill it 1/2 full. Mind you the aps supplied overflow is MUCH too small, so the amount of expansion seems like a lot.
So now I continue to drive the car hard and come to an idle with little cool down driving and let the car sit, still running mind you. I would lose heat for a short time, bring the revs up a bit, and the heat would come back, but a nice coolant spout would shoot from the overflow. The turbos are creating a localized hot spot in the system and boiling the coolant most notable under two conditions
1.) hard driving followed by a quick idle session
2.) hard driving followed by a quick shut down.
****but any spirited driving could induce a localized hotspot which would introduce air into the system the way it comes from the factory
The coolant travels from the LHS of the motor through LHS turbo, under the motor to RHS turbo, then back up by the stock bleeder... this is just too much for the system. Now I have boiled coolant being fed back into the system with now where for the air to go. Usually I find it gets stuck by the stat or back in the heater core. Once we get air in the system, it's a nasty downward spiral to overheating.
So now I am hitting the web to figure out what I can do about this. I come across terms like surge tank, expansion tank, overflow tank, header tank, breather tanks. Surge/expansion/header/breather are kind of used interchangably, but are different from an overflow. what it comes down to is the fact that our fill and header tank is not the highest point in the system. We need to change that. Look at the GTR coolant system. They have a dedicated expansion tank... basically fully redesigned coolant system. that system is what we need to retrofit into our DE setups.
I came across VERY limited talk about surge tanks/expansion tanks on this forum, but I did come across one. of ALL the issues with the DE system, we have, for the most part ONE person that isn't completely clueless? I did later find some SGP cars with breathers, but nobody said boo about them.
I am in the process of trying to find a suitable expansion tank to fit the limited space I have in the engine bay. djtimodj's design in the link above is what I am going for, except I want directly run the feed off the turbo into the tank without splicing in silicone hose. I have a few more things in the way with the APS big fuel system, so fitment is very challenging. I am thinking of having a custom one made locally to fit the area......
the reason I post this before I have fitted mine is to see if anyone has insight into some custom tanks before I head to a local fabricator?
I know I didn't cover everything so if people have questions, post them up and I'll do my best to answer them. I have been working on this the past 10 days and done a lot of troubleshooting, bleeding, testing on my system.
Last edited by Zivman; 10-22-2012 at 08:58 PM.
10-23-2012, 05:14 AM
#2
How about running the coolant lines in parallel instead of series? Increase flow? Draw from the cold side of the coolant system instead of hot side? Bigger expansion tank just seems like a band-aid to me...you really need to stop the boiling.
Last edited by djamps; 10-23-2012 at 05:18 AM.
10-23-2012, 06:03 AM
#3
the thing is, I am not just going to introduce a larger expansion tank... the system is flawed. We really don't have one the way the system sits. the top tank of the radiator is basically the expansion tank. because it is not the high point of the system is really the issue that needs to be corrected. that is what I am proposing
10-23-2012, 06:29 AM
#4
I thought I was the only one having this problem. I'm on an N/A engine but weather here's hot. When I go out and play at the track, this same thing happens. At one Time Attack competition, I had to quit because most of the coolant was sprayed out during the practice and the engine started heating up. Everytime i drive the car really hard, I see coolant all the way up on my reserve tank. We need a proper solution for this. .. frikkin air bubbles!
Subb'ed.
So "breather tanks" don't help at all?
Subb'ed.
So "breather tanks" don't help at all?
10-23-2012, 07:14 AM
#6
I thought I was the only one having this problem. I'm on an N/A engine but weather here's hot. When I go out and play at the track, this same thing happens. At one Time Attack competition, I had to quit because most of the coolant was sprayed out during the practice and the engine started heating up. Everytime i drive the car really hard, I see coolant all the way up on my reserve tank. We need a proper solution for this. .. frikkin air bubbles!
Subb'ed.
So "breather tanks" don't help at all?
Subb'ed.
So "breather tanks" don't help at all?
basically a pressurized tank mounted as the high point of the system. this tank is filled only partially with coolant. the top portion of air in the tank is part of the system and allows for coolant expansion. the top inflow to the tank comes from the hottest point of the system. In your case being N/A it would be the line coming off the heads. basically plumbing off one of the lines going to or from the heater core
what we have now is simply an overflow. it is not part of the pressurized system.
These tanks are very common in RB26 systems, and come stock on a lot of euro cars. this isn't really a band-aid. it's correcting a poor design. The R35GTR comes stock with this.... do you consider the GTR's setup to be a band-aid? heck, on the spec-V GTR, they increased the expansion tank to 3qts, up from 2 qts on earlier models
Last edited by Zivman; 10-23-2012 at 07:37 AM.
10-23-2012, 07:29 AM
#7
here is some more info on some of my 'testing' that I worked on, on saturday-
well after about 5 hrs of messing with the car... had to do some farm work here and there while I was heat cycling it, but it was the better part of 5 hrs. I really don't think I have internal issues.
I pulled the stat, had to disassemble the SOB as it comes as a complete housing, I cut off the toggle check valve, and drilled it out to 9/64, I then drilled two smaller holes on either side of it. reassembled it and reinstalled it. I then started bleeding the system, which took over two hrs. I did two heat cycles with just the tower funnel and two with the cap. I had the front end up on the hoist during the bleeding procedure.
We pulled the hood in prep to run a pressure tester on the system to see what kind of pressures the coolant system was seeing under boost. the tester wouldn't fit under the hood.
So after the stat modification, and 2 hrs of bleeding the system, I hit the road. I have a closed course 1-1/4 mile strip near my home. I proceeded to do pull after pull after pull. 3rd gear through 4th at full boost. I did this for over an hr, with a few idling sessions to check the coolant level in my overflow/expansion tank. after almost an 1 and a 1/2 hrs of this, I filled the overflow to about 3/4 full (from 1/4 full at start).... I am guessing maybe 16 oz of fluid. I did lose heat one time, but it came back quickly and I never saw my coolant temps spike like I did previously.
When I would come off an idle session, I would get a quick spike of about 10-15 degrees -> 195 to about 205. This is telling me that once I increase flow coming off a few minutes of idle, a hot spot is working its way through system. this is why I think I am getting some aeration from small hot spots in the system - mainly the coolant line coming off my turbos.
This is legitimaty the hardest I have driven my car in the 8+ yrs I have owned it, I had oil temps up to 242. in terms of coolant problems, I definitely didn't have the issues I saw over the past week or so. If it were a head gasket issue, I would have shown here today.
This is my HKS Camp2 readout. This is coming off the last pulls of the day.
I have gone through a few caps. I used to just run oem 300z turbo caps from nissan. I would change them out yearly. I did pickup a 1.3 (18#) koyo cap this past week and have been using that.
I spent a couple hrs last night researching cooling systems. What I really think I need is not technically a swirl pot, but a larger expansion tank, and it needs to be moved to the rear of the motor, near where the heater core line exists from the fire wall (basically where the oem purge is).
After my work yesterday I firmly believe this is an issue with a poorly designed cooling system. I think I am getting some localized boiling off the turbos. the air created has no where to escape. on a conventional system, this air would find it's way to the header tank on the radiator. In my case, my radiator sits lower than the motor, so this air stays trapped within the sytem. I am finding it stays either back on the back side of the motor near the heater core, or worst case scenario trapped by the thermstat. Drilling the stat I think I alleviated part of the problem, but I still need to address the fact my radiator is the low point in the system.
I continued to drive the car:
drove the car up to the gym... pulled off some epic lifts
but that is for another section of the forum.....
anyways, did some pulls on the way home. temps got to about 192-194. I pull into my driveway and my brother had my dad's truck, which he left at my house while he is out of town. anyways he parked it so I couldn't get the car in the garage. so I let my car idle as I went to grab the keys and move it. I checked the overflow as I went in. it held constant, no issues........
.
.
.
I move the truck, and proceed to pull my car into the garage. and all of a sudden I get a nice little spout coming out of the overflow. this is confirming that as the flow decreases at idle, the coolant is boiling somewhere in the system -> the turbos. as I increase the flow/bring up the revs a bit, it moves that boiled coolant through the system and the vapor can't find it's way out and I get increased pressure and it pushes coolant.
here is a pic of the SGP's setup:
well after about 5 hrs of messing with the car... had to do some farm work here and there while I was heat cycling it, but it was the better part of 5 hrs. I really don't think I have internal issues.
I pulled the stat, had to disassemble the SOB as it comes as a complete housing, I cut off the toggle check valve, and drilled it out to 9/64, I then drilled two smaller holes on either side of it. reassembled it and reinstalled it. I then started bleeding the system, which took over two hrs. I did two heat cycles with just the tower funnel and two with the cap. I had the front end up on the hoist during the bleeding procedure.
We pulled the hood in prep to run a pressure tester on the system to see what kind of pressures the coolant system was seeing under boost. the tester wouldn't fit under the hood.
So after the stat modification, and 2 hrs of bleeding the system, I hit the road. I have a closed course 1-1/4 mile strip near my home. I proceeded to do pull after pull after pull. 3rd gear through 4th at full boost. I did this for over an hr, with a few idling sessions to check the coolant level in my overflow/expansion tank. after almost an 1 and a 1/2 hrs of this, I filled the overflow to about 3/4 full (from 1/4 full at start).... I am guessing maybe 16 oz of fluid. I did lose heat one time, but it came back quickly and I never saw my coolant temps spike like I did previously.
When I would come off an idle session, I would get a quick spike of about 10-15 degrees -> 195 to about 205. This is telling me that once I increase flow coming off a few minutes of idle, a hot spot is working its way through system. this is why I think I am getting some aeration from small hot spots in the system - mainly the coolant line coming off my turbos.
This is legitimaty the hardest I have driven my car in the 8+ yrs I have owned it, I had oil temps up to 242. in terms of coolant problems, I definitely didn't have the issues I saw over the past week or so. If it were a head gasket issue, I would have shown here today.
This is my HKS Camp2 readout. This is coming off the last pulls of the day.
I have gone through a few caps. I used to just run oem 300z turbo caps from nissan. I would change them out yearly. I did pickup a 1.3 (18#) koyo cap this past week and have been using that.
I spent a couple hrs last night researching cooling systems. What I really think I need is not technically a swirl pot, but a larger expansion tank, and it needs to be moved to the rear of the motor, near where the heater core line exists from the fire wall (basically where the oem purge is).
After my work yesterday I firmly believe this is an issue with a poorly designed cooling system. I think I am getting some localized boiling off the turbos. the air created has no where to escape. on a conventional system, this air would find it's way to the header tank on the radiator. In my case, my radiator sits lower than the motor, so this air stays trapped within the sytem. I am finding it stays either back on the back side of the motor near the heater core, or worst case scenario trapped by the thermstat. Drilling the stat I think I alleviated part of the problem, but I still need to address the fact my radiator is the low point in the system.
I continued to drive the car:
drove the car up to the gym... pulled off some epic lifts
but that is for another section of the forum.....anyways, did some pulls on the way home. temps got to about 192-194. I pull into my driveway and my brother had my dad's truck, which he left at my house while he is out of town. anyways he parked it so I couldn't get the car in the garage. so I let my car idle as I went to grab the keys and move it. I checked the overflow as I went in. it held constant, no issues........
.
.
.
I move the truck, and proceed to pull my car into the garage. and all of a sudden I get a nice little spout coming out of the overflow. this is confirming that as the flow decreases at idle, the coolant is boiling somewhere in the system -> the turbos. as I increase the flow/bring up the revs a bit, it moves that boiled coolant through the system and the vapor can't find it's way out and I get increased pressure and it pushes coolant.
here is a pic of the SGP's setup:
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10-23-2012, 08:21 AM
#9
definitely an option... but I think things like this are really band-aids to a poorly designed cooling system. the pump would still do nothing when we get some boiling while driving
IMHO if the system was designed properly, it could handle the localized hot spots without issue.
IMHO if the system was designed properly, it could handle the localized hot spots without issue.
10-23-2012, 08:22 AM
#10
Could you route the coolant return off the turbo differently? If the air is coming from there, make sure it ends up somewhere it can purge e.g. a catch can type setup like in the SGP pic (not sure how that would work) then the upper rad. hose... just throwing ideas out there.
Last edited by djamps; 10-23-2012 at 08:27 AM.
10-23-2012, 08:33 AM
#11
hatersgonnahate
iTrader: (162)
definitely an option... but I think things like this are really band-aids to a poorly designed cooling system. the pump would still do nothing when we get some boiling while driving
IMHO if the system was designed properly, it could handle the localized hot spots without issue.
IMHO if the system was designed properly, it could handle the localized hot spots without issue.
Maybe go with oil cooled journal bearing turbos.
The EWP could keep a constant flow ( would need to be parallel to stock or remove stock) so that at idle, low RPMS you do not have stagnant coolant.
Evans NPG?
Never had an issue when we bled my Z. Was super easy. We did a few heat cycles and fills and were done. No overheating after driving 1.5hrs in summer heat from one house to another.
10-23-2012, 08:46 AM
#12
I need to make a diagram, but basically by adding that "can" you have essentially moved the header tank from the radiator and now that can is the header/expansion/breather/surge tank.
There is a disconnect in our system. To make a system easy to bleed, the header tank should be the high point of the system. where we fill our system is at the radiator neck. ideally the radiator would not be full to the top with coolant. It would be down an inch or so from being full of coolant. leaving a portion open with air. the top air pocket would allow for coolant expansion as the coolant got hot. the air would be part of the pressurized cooling system. We don't have that in our system, because that expansion tank is not the high point, so we have to get every last bit of air out of the system...
stay with me here.... when we have a fully enclosed system, filled 100% with coolant, we have a problem. We heat the system up, coolant doesn't compress. It can change to a gas, but it cannot compress, so as the system heats up, so does the pressure... at a certain point, it will push the coolant out of the system, into the overflow. we have no area to allow for expansion within the closed, pressurized system.... once it is pushed outside, it will only be sucked back in under vacuum conditions. the issue now becomes we have displaced coolant in the system with air that has been created by boiling coolant. that air keeps the system pressurized and the displaced coolant is outside this pressurized system. the coolant will not flow from a low pressure environment to a higher one, so the system will not pull it back in as long as the system stays pressurized.
I need to draw up a diagram of how I intend to plumb my system, but essentially it goes like this
1.)mount expansion tank so it is the high point of the system. tank has pressurized cap on it - preferably a 16-18 # cap from my experience
2.) have two inputs on the upper part of the tank you just mounted
- a) first is a feed from the hot point of your current system. in most cases this would be the return off of the heads. In my case it would be the return off the turbo
-b) second would be 1/8" port off the radiator
3.) tank will have a bottom port on it. this port is plumbed to the lower radiator hose... or basically any line that is feeding the water pump - ie cool side of the system
4.) the current filler neck of the radiator is caped with a non pressurized filler cap... basically a cap with no spring assembly. You can see it in this vid... skip to 1:20
http://youtu.be/dLwkx3joV5A?t=1m20s
5.) route the 1/8" neck port to the current overflow tank
you then fill the new tank about 1/3-1/2 full with coolant, purposely leaving a portion of air in the system. with this being the high point, you don't have to worry about it finding it's way through the system as long as you have bled the system of air elsewhere. this pocket of air is what allows for coolant expansion without risking displacing the coolant outside of the pressurized system with air pockets, like we currently have issue with in our stock system.
Last edited by Zivman; 10-23-2012 at 08:53 AM.
10-23-2012, 09:00 AM
#13
BMW uses EWP's on their TT engines. Not sure if the turbos are watercooled though.
Maybe go with oil cooled journal bearing turbos.
The EWP could keep a constant flow ( would need to be parallel to stock or remove stock) so that at idle, low RPMS you do not have stagnant coolant.
Evans NPG?
Never had an issue when we bled my Z. Was super easy. We did a few heat cycles and fills and were done. No overheating after driving 1.5hrs in summer heat from one house to another.
Maybe go with oil cooled journal bearing turbos.
The EWP could keep a constant flow ( would need to be parallel to stock or remove stock) so that at idle, low RPMS you do not have stagnant coolant.
Evans NPG?
Never had an issue when we bled my Z. Was super easy. We did a few heat cycles and fills and were done. No overheating after driving 1.5hrs in summer heat from one house to another.
sure there are band-aids like evans, but what I am proposing is true fix to a poorly designed system. Why try to band aid the system, when a small addition, running a few lines resolves the issue once and for all? again, I ask, is the GTR system flawed? why did nissan change the way the system is on the HR motors, putting a fill higher up in front of the motor?
I have gone full yrs without issue as well, but now that I know what causes the issue, I can easily replicate it. Casual driving for an hr or two is not a problem.... never has been. I had my car out doing 3rd to 4th pulls one after another, 14-15 psi for the better part of 1.5 hrs, no issues. So even hard driving really isn't the issue.... now come off a hard pull and let the car sit at idle for 2 minutes and it will, best case scenario, spike the temps 10-20 degrees as I start driving, or worst case, push coolant as I bring the revs up.
I am not sure what turbo system you are running, but the way my system is setup, it will continually be an issue.
even if one doesn't have the issues I have, bleeding this system is a PITA. fitting a proper expansion tank will ease the bleeding procedure
Last edited by Zivman; 10-23-2012 at 09:05 AM.
10-23-2012, 04:04 PM
#17
I have found the expansion tank I think I am going to run. I am going to look a bit more tomorrow, but this one is definitely the best for my setup I have been able to find thus far.
http://www.summitracing.com/parts/HRE-3424/
it is a horizontal mount, has two in ports, and will fit in my space.
http://www.summitracing.com/parts/HRE-3424/
it is a horizontal mount, has two in ports, and will fit in my space.
10-23-2012, 04:07 PM
#18
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I do not have my car running yet, but my setup is very similar to yours. APS twins on de. I have the APS tall boy intake and altered atmosphere fuel rails. I mounted a carbing swirl pot to the intake manifold back passengers side. Very high. Kind of above the fuel rail. I have the pathfinder cooling mod and shaved the front crossover hose. moved the stock coolant temp sensor to the metal pipe above manifold and put a 6an fitting in the pathfinder pipe to feed the coolant to the turbos. Then I took the 6an that was the feed for the aps kit ( originally was the bleed). and connected it to a top port on the pot, and the outlet from the radiator cap to the other top port. Then the bottom port to the lower radiator hose. Run a blank cap on radiator and a regular style cap on the pot. Then overflow from the pot to the aps overflow tank. This should allow the system to bleed the air automatically. Alot of thought and experience has went into this system and should work great. So people complain about the shaved front crossover and I don't know if you have done that but the reason it is there is to allow coolant to pass around the thermostat to alow it to open up. If there is no coolant flow in the system the water will never get hot at the thermostat. With the crossover gone the heater core and the turbo cooling will allow enough flow to keep water circulating.
10-23-2012, 04:19 PM
#20
I do not have my car running yet, but my setup is very similar to yours. APS twins on de. I have the APS tall boy intake and altered atmosphere fuel rails. I mounted a carbing swirl pot to the intake manifold back passengers side. Very high. Kind of above the fuel rail. I have the pathfinder cooling mod and shaved the front crossover hose. moved the stock coolant temp sensor to the metal pipe above manifold and put a 6an fitting in the pathfinder pipe to feed the coolant to the turbos. Then I took the 6an that was the feed for the aps kit ( originally was the bleed). and connected it to a top port on the pot, and the outlet from the radiator cap to the other top port. Then the bottom port to the lower radiator hose. Run a blank cap on radiator and a regular style cap on the pot. Then overflow from the pot to the aps overflow tank. This should allow the system to bleed the air automatically. Alot of thought and experience has went into this system and should work great. So people complain about the shaved front crossover and I don't know if you have done that but the reason it is there is to allow coolant to pass around the thermostat to alow it to open up. If there is no coolant flow in the system the water will never get hot at the thermostat. With the crossover gone the heater core and the turbo cooling will allow enough flow to keep water circulating.
You have it down perfectly... post up pics of your setup