in the engineering practice we have a saying for troubleshooting “change any one variable and see what happens” I’m sure you’ll figure it out if you keep playing with it, did you ever trace the wires back to the ecu? You might try disconnecting the solenoid and measuring the continuity from the ecu connector to the solenoid connector. That would tell you if you have a bad wire or short somewhere. I’m sure you already have but just incase, have you checked the solenoid grounds? We’re at a point where these cars are old enough to start suffering from dry rotting and heat damage to the harness, a broken wire can be a very hard problem to identify with all the wire loom involved in a modern day harness

 

I made a very foolish mistake and left runner plugs in the plenum/intake (yea, I'm an idiot) and ran the engine for about 3minutes ... essentially the engine suffocated itself and stopped ... was deathly worried I damaged either the valves or the rings ... removed everything to get the runner plugs out, inspected, reinstalled the intake, ran a compression check on the cold engine.

I'm very happy (and relieved) that the compression checked out. I'm more just documenting it. Gotta factor in that I am running 9.1 : 1 CR - so Im not worried and if nothing more I have a data point for the future.

I dont think I mentioned it above but I loaded a tune from about 2months ago and the VTC issue went away ... frustrating as all hell. Reloaded PC Link and checked that firmware is up to date on the Link then use that same map and copy/paste my fuel values into it and drive the car a bit. Still need to get it in for a tune but dont want to take a malfunctioning car in.


Yea, checked both sides and they have continuity. and did the same thing for the VTC sensor sides too.

I will measure resistance of the connections and grounds but I think everything is fine. I think it's ecu / tune related.

One step at a time!

 

Interesting so just a bad or corrupted file, well I would take that over a mystery issue any day. Glad you figured it out

 

I hate it! I need to know it's fixed … grrrrrrrr frustrating

 

Could there be any damage to the wiring? Probably not the case, but maybe.

 

soooooo… mostly good news …
the new set of VTC sensors cured the issue … the sensors were not consistently give the ECU a good-enough signal and my cam-shaft position offsets (which I don't completely understand) were slightly off. The good news is that I was not off on timing (a huge fear) and the cam-shaft position sensors and crankshaft position sensor are syncing up.

New sensors install and offset values recalibrated and shes running …

I also swapped in a different VTC solenoid on the passenger side and forgot to plug it in … so with two new sensors the ECU was seeing the correct positions and applying a consistent duty cycle but the but the commanded duty cycle was not being registered on the passenger side … I almost got the solenoid off the car before I realized it was unplugged. Torqued back down and plugged in and it's running right.

I'll get on the board for the tune this week … who knows their schedule

 

Glad to hear you found a solid solution to the issue

 

That is awesome! Glad to hear it is all working now.

Remember your timing will be every so slightly of when you deck a block and heads. This can be compensated with thicker headgaskets; but I'm not sure its enough to worry about unless running supper agressive piston to valve clearances.

 

I feel my car has been a roller coaster as of late and I am very thankful that everything has turned out ok ... and here's another episode

Im welding charge pipe and exhaust stuff for a mitsubish 3000gt vr4 and its in my spot in the garage and I didnt put my car in the garage overnight last saturday (bc I'm dumb) and sure enough a cold-front rolled in and dropped 4" of snow over night and my car was outside ... I didnt think much of it until I went outside and realized I was pissing frozen green slush out of one of my coolant hoses near my radiator ... I immediately went into freakout mode. The car started fine and I ran it for a few minutes to get some heat into the block.

one of those 'stomach sinking' moments to say the least ...

I got the vr4 on the ground and backed out of the garage and my car pulled in and a 240v space heater on the radiator/hoses/block along with a few more ~3minute start-ups/idles. As things heated-up coolant flowed out of the compromised hose and from my turbo aswell. The compromised hose (radiator's low side) was frozen hard/solid, while the top side was still soft, further, the coolant in the radiator, overflow tank, and fill ports were slushy ... got the car room temperature and all the coolant leaked out of the engine. I didnt see any coolant under the engine during this flush/run-time...very thankful

Fast-forward to today and ran a compression test on the engine and everything came in fine (between 115psi and 125psi)...

moving forward, I think it's time to go trunk-mounted radiator...it has many benefits (putting weight over the rear axle, moving weight from the front of the car to the rear of the car, allowing me to pull the intercooler in and fitting a front bumper on the car, and allowing more room around the turbo).

Further, to mitigate this ruptured hose and to do it right is going to be rather costly ... 3ft of AN-20 hose is $90, new fittings are (I kid you not) $80 a piece for a respectable brand. ... so I'm gonna keep this setup and not canabilize anything from it and look at some options for a rear-mounted radiator setup ... possibly two small or two medium sized radiators and naca ducts off the hatch window. Initially, I'll probably run a rubber hose to ensure the concept works and then fabricate aluminum hardlines and run them along the bottom side of the car - I think aluminum will provide some heat transfer and longevity against road debris.

for the archive:
1-118psi
3-120psi
5-120psi
2-115psi
4-120psi
6 -125psi

*I've never seen up to 125psi on a cylinder in the past few years ... I can only assume that the engine oil was cold and provided a better seal?? I believe cylinder 6 was done last.

 

Glad nothing was damaged on the engine! And I know what you mean on the 20an fittings even a straight hose end is like $50 and if you want any kind of 45,90,130,150,180 the price almost doubles 😱 it’s seriously ridiculous anything above 10an and the prices just skyrocket but the durability and reliability are in the long run probably worth it, at least that’s what I tell myself rocking back and forth looking at my bank account 😂

 

Yea - crazy expensive! Essentially this is a $500 mistake … and there is benefit to moving it to the trunk area that are high priority benefits so it just makes sense to. Also, it's winter and I wont be driving the car much anyways.

I'm trying to do conceptualize what size of radiator I will need. I currently run a 18" tall x 22" wide dual pass, which has +/-900cubic inches of radiator capacity and 8ft (96") of 1"diameter hose 76cubic inches of hose capacity. For rounding, that's 1000cubic inches of coolant capacity that I need to re-produce.

I'm essentially going to look for a similarly sized radiator … the system will have more capacity overall seeing that I will have 20 to 24ft of hose but will the radiator have the same cooling efficiency seeing that it's no longer in the passive air flow?

I'm on the hunt and I really want to stick with C&R Racing but I'll look at PWR and Fluiddyne as well.

 

From my understanding, PWR bought out C&R, and C&R is now the U.S. division of PWR. Are you running stock water pump? What fan size do you plan to use? The extra line will not help with cooling rate, only in the capacity. It will make it slower to heat up, but also slower to cool down.

CI of capacity is a rough way to estimate cooling capacity, but it is a difficult area to approximate as is. With 900ci you should be good for just about any amount of abuse given that you have ample airflow over it. I would even say that you would be okay sizing down to somewhere in the 600ci area as long as you maximize the airflow. An additional water pump is also something that you may consider. The Davies Craig EWP 115/150, run inline can greatly boost the coolant flow for when the engine is warm, increasing cooling ability with the same size of system. Additionally, radiator thickness is the opposite of thermal effectiveness. A thinner rad with the same C.I. will perform better than a thicker rad, given the same airflow.

I have also had great experience working with Power Cool Systems for custom radiator builds. They can build a full custom unit that is cheaper than a C&R unit with the same performance or better. I have worked with both.

 

Yea, I knew that PWR bought C&R but I didnt understand C&R was dedicated to the US.

Yea, stock water pump ... not sure if I have to run a pump ... would you put it closer to the hot side on the engine? or would you put it on the cold side of the radiator.

I have a 14" spal, a 10" spal and two 6" spals on the shelf.

Do you think if I were to run a hard line under the car it'd add cooling capacity? was thinking a 1" feed and 1" return +/-

thanks for the info and the shout to Power Cool - I'll check them out

 

I am not certain on that regarding C&R/PWR, but that is my understanding.

If you were to run an additional pump, I would run it after the radiator, on the return line. They come with a temperature control unit that you set up that will control the pump, I have also set them up through the haltech/standalone with a solid-state and a PWM output from the ecu to be controlled independent of rpm and only dependent on temperature.

Any idea on the flow rates or part numbers? My first though would be the two 6" next to the hot side tank and then the 14". Sizing the rad somewhere around 16Hx23Wx1.75D depending on space. If you did not have fans, I would recommend dual Spal VA03-AP90-/LL-68A.

I agree on the 1" id line, defiantly not smaller. You would probably get <<10% of the cooling from the line, and I would guess less than that. Remember that the air under the car is hot. Most of the air coming though the oil cooler, intercooler, headers and from the bay goes under the car unless you have a flat floor. This air is so hot that there is no heat transfer to be had. With a flat floor all that heat is trapped in and probably adds heat to those lines.

 

I'm leaning towards an additional pump and it looks like Power Cooling Sys has pumps built into the radiator. To keep it simplified I would put the pump on a keyed-on relay or use the Link's ability to control the OEM radiator fan circuit on the pump. Meaning Link will control up to three fans (although OEM is only wired for two) I would run a single fan to kick-on at/around 190degrees and use the second circuit to kick the pump on at/around 50degrees. I don't always like to rely on technology or electronics so maybe a by-pass hose around the pump with a ~1psi check-valve incase the pump were to fail.

I think the 6" spals are like 300cfh, the 10" is like 900cfh, and the 14" (and it might be a 16" - I can't remember) is like 2100cfh.

makes sense on the heat dissipation of the lines … was thinking an aluminum hardline would shed 'some' heat … but the bigger benefit would be capacity.

my buddy / shop partner is huge on naca ducts - what are your thoughts on adding two sets affixed to he hatch lexan?

Your dimensions of the of radiator or more tall than wide - any reason not to go more like a 26" x 12" x 2" … I'm tempted to go thicker (and I understand the consequences) and wider to reduce the height - Ideally I would like to mount this directly under the rear tower brace.

 

I had not seen the pumps integrated into the rad. Interesting. It may need a speed controlled turn-on via the controller or the ECU and a solid-state relay so that it doesn't get weird temp oscillations with the thermostat. I am not sure on that.

If there were not other options, then the rear lexan may be okay. I think large ducts in the rear quarter windows would get more airflow than the rear glass.

Its hard to put a 14" fan on a 12" rad, which is where my 16" came from with a little room for a duct. Longer flow directions also cause higher pressure drop in the fluid. at 26" x 12 I would look into putting the water flow in the 12" direction. but then the tanks on the top and bottom would add to the size.

 

been all over the map with life … but managed to make small steps with the trunk-mounted radiator...In the essence of money I am going to re-fit my current radiator in the trunk. I actually like the layout and I can always change it down the road if I don't like it. I also think it provides sufficient volume/coolant capacity compared to the other radiators I was looking at, also make frees-up $200 to $400 for other stuff (likely an oil cooler). I bought new aluminum for a radiator mounting bracket and made a simple square design (like the previous setup) and will mount it below the strut tower brace bolted to the chassis and hanging brackets on the topside. I ordered 1.25" radiator hose and for the time being I am going to use my existing fittings (minus the locking collar) and I'll put a hose clamp to secure them. If this work I'll purchase push-lock fittings but this works for now.

Got going on the fabrication of the intercooler bracket. I'm mimicking the previous design except it'll sit ~4" closer to the engine/turbo and I'm using a 3" square tube (compared to the 2" I used previously). I didn't realize this initially but the intercooler is going to hang below the floor of the chassis by about an inch or so … To combat this I am going to lean the intercooler forward at ~30 to 45 degree angle and it'll fit...sorta V-mount but not all the way.

also picked up a pikes peak white bumper … one popped up for sale in Colorado Springs and pulled the trigger on it (one of the reason I'm economizing above^^).

Still waiting on a few new -20 fittings, an replacement OEM rear hard pipe, thermostat housing, two naca ducts, and some 3" ducting hose

more to come …

 

I've seen trunk mount radiators in trucks, but never a car. What is the plan to get air in and out? If you use a trunk kind of ran air scoop how is that going to affect aero at higher since that air is no longer going over the rear bumper to provide down force?

I'm thinking Lambo style scoops left and right, this should provide the cleanest air to the radiator with out affecting down force. With this though you need to determine what size scoops give the best air pressure to air velocity. To get the air out will be tricky. How do you get a clean looking exhaust while still allowing for the best possible path.

 

You only live once! I am trying to do this to where if I have to rip this out and put it back up-front, I can. My buddy Reilly is pretty sharp with these things and I am spring-boarding his imagination, so we dreamed up two 3" naca ducts in the top corners of the lexan of the hatch and pipe that down to the front of the radiator, along with one or two fans and the duct the back side of the radiator through the two OEM vents in the rear of the car (that Nissan installed specifically for me).

 

I'm not sure those two little ducts will provide enough CFM's to allow sufficient air flow. I would think at minimal you would want 75% of the surface area in escape room, if that makes sense.