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Andyrew
Looks great!!

What size hoses did you go with?
Chris H.
QUOTE(Andyrew @ Mar 4 2016, 01:11 PM) *

Looks great!!

What size hoses did you go with?


Guess I better order the 1.25 eh Kent biggrin.gif ? You ready for it? If you want to try the existing setup first that's totally cool.

Your radiator support it AWESOME man. Nice work. I have literally the exact same radiator setup. You'll love it.
76-914
QUOTE(Andyrew @ Mar 4 2016, 11:11 AM) *

Looks great!!

What size hoses did you go with?

Thx Andy. The hose size is still up in the air. I need to get this set up running, compare notes then I'll decide. It may not be necessary. Bob (BigKat83) is running the same size hoses albeit a different route and a larger radiator than my old radiator, w/o a hitch. However, I'm not sure if he spools it up and keeps it there. That is when I experience the temp rising. So, if what I believe to be a cavitation problem persists and/or the temps won't stay in range without "fan action" when rolling then I'll run 1 1/4" beneath the car.

EDIT: Just read your post Chris. I'll know in the next week to 10 days. Have 2 birthdays this week so I may not be ready this weekend. sad.gif Did you get to work on Blue this weekend? beerchug.gif
Chris H.
Yeah no rush at all. Just wanted to make sure I wasn't holding you up. I say try it how it is. Probably be fine.

I'll be working on mine this weekend for sure. Hope to get that engine out.
76-914
I was able to squeeze in a quick run this evening after reconnecting the hoses and topping off the coolant. The new radiator added about 1 qt to the cooling system capacity. I let it idle about 10 min. and the Subie factory gage was approaching the mid point i.e. operating temp, when I pulled out of the garage. I drove around the hood for 10 min's (<40mpn & 55F) and the needle never moved nor did the fans kick on. Ran it up to 55mph and the fans kick on. Drop to 40 and they go off, and so on.
This is the 1st noticeable improvement. I will pull the fan's fuse before the next run to see what happens to the temps at 55mph+. Either the sensor cut in / cut out is not compatible with this system, in which case I'll go to an after market sensor, or it's time to order some 1 1/4". When the OLD radiator was installed it took several minutes for the fans to shut down after they came on. As stated above, they only came on above 55mph tonite. They also would kick in on the hi way quite often with the old radiator in place. I may find that this isn't an "and/or" scenario but an and/and scenario. More later. beerchug.gif
914forme
Sounds like great progress.

I am going 1-3/4" on cold side 1-1/2" on hot side. There is enough room on the EG to go full 2", but 1-3/4" seems like it should function just fine.

Can't wait to see your results. popcorn[1].gif Might make me change my mind.

76-914
Just noticed your question Andrew. 7/8 & 3/4".

Today I drove with the fans fuses pulled. I drove around the "hood" for 10-15 mins w/normal stop n go. OAT was 75F and speeds were < 45mph. Engine temp stayed centered. I then hit the Wine Country back roads for another 30 mins. OAT 75F, speeds < 62mph, engine temps still centered. AHAAH I thought those fans were running too much and now I know they were.
All this thought about changing my cooling system began when I installed a light to tell me when the fans were running. I noticed they came on (and off) when on the hi way. The temps were always centered but damn it, those fans shouldn't have been on. I also noticed that if I stopped then started the engine the fans did not come back on, although they had been running 10 seconds before???
So the cut in/cut out factory set points do not appear to be the best set up for my system. Looks like an adjustable fan controller is in my future. I should be able to dial it in quickly as I know what the temp gage should read.

Next test hop I plan to run some realistic hi way speeds 70-80mph with a bit of higher RPM driving to test for 2 things. Both were mentioned in an article that George posted in Chris' thread. One is cavitation the other is high pump head pressure. More later.
Chris H.
I ditched my ECU fan controls. Never ran right for some reason. Installed the Derale 16759. It has an AC override circuit. Very easy to wire up to a switch if you want to run it continuously too. It's about 99% less complicated and only requires one relay which is included. The initial factory setting is WAY low on the Derale BTW. Kicked on at like 170 or something. Easy to adjust though.
914forme
You can also look at the PWM Fan controller.

It is a bit more, 65 Amp capacity, and A/C override. Big difference is it controls fan speed so the fans are only turning at a high speed when the need to be. This reduces noise and amperage loads.

Derail makes some nice stuff.
76-914
QUOTE(Chris H. @ Mar 9 2016, 07:57 PM) *

I ditched my ECU fan controls. Never ran right for some reason. Installed the Derale 16759. It has an AC override circuit. Very easy to wire up to a switch if you want to run it continuously too. It's about 99% less complicated and only requires one relay which is included. The initial factory setting is WAY low on the Derale BTW. Kicked on at like 170 or something. Easy to adjust though.

I was reading the negative reviews on this model and decided that I should go w/ an upper line model. Then I noticed the same complaints re: models that are 2-3 times as much. That's when it occurred to me that the problems with any of these units is most likely theINSTALLER. More especially, those that were received DOA. One guy said he had 2 dead ones in a row. Riiiiiiiiight. Notice he ordered another brand after that. One with pictures instead of words. lol-2.gif Think I'll try one of these! Did you get that engine out last weekend? beerchug.gif

QUOTE(914forme @ Mar 10 2016, 02:16 PM) *

You can also look at the PWM Fan controller.

It is a bit more, 65 Amp capacity, and A/C override. Big difference is it controls fan speed so the fans are only turning at a high speed when the need to be. This reduces noise and amperage loads.

Derail makes some nice stuff.

Yea Stephen, I would go with this but it is overkill for me. I did like the manual override feature, though. If your running dual fans and want an adjustable model the field quickly drops from over 50 units to just a couple of units. The variable speed feature is neat but I'm hoping my fans won't be required so much that I need a feature like that. The fans that came with this unit are only 80 watt ea. (80/12=6.66amps ea.).
Andyrew
Im going to be running the Davies Craig water pump and LCD control panel, it circulates both the water pump and fans perfectlg for speed and timing to maintain the desired temperature.

I got both for ~320 shipped from australia. Theres a link to the ebay auction/seller in my thread, ill get it in a bit.
rnellums
QUOTE(Andyrew @ Mar 11 2016, 08:53 AM) *

Im going to be running the Davies Craig water pump and LCD control panel, it circulates both the water pump and fans perfectlg for speed and timing to maintain the desired temperature.

I got both for ~320 shipped from australia. Theres a link to the ebay auction/seller in my thread, ill get it in a bit.

This is very interesting!
Chris H.
QUOTE(76-914 @ Mar 11 2016, 08:34 AM) *


I was reading the negative reviews on this model and decided that I should go w/ an upper line model. Then I noticed the same complaints re: models that are 2-3 times as much. That's when it occurred to me that the problems with any of these units is most likely theINSTALLER. More especially, those that were received DOA. One guy said he had 2 dead ones in a row. Riiiiiiiiight. Notice he ordered another brand after that. One with pictures instead of words. lol-2.gif Think I'll try one of these! Did you get that engine out last weekend? beerchug.gif



Yeah it's VERY easy to install. Given what you've accomplished with your harness this is a snoozer. Everything is very well labeled. I think I posted the instructions in my build thread. Guessing the guy who had 2 dead ones crossed the positive and negative wires ... which DOES release the magic smoke. Even I know that. Bob recommended this one BTW (shocker).

I have the engine ready to drop. Just gave it a few days for this green stuff to drip off (antifreeze). I have a couple of small dogs, so a few drops would be deadly for them. Will drop it later today and post some pics!

76-914
For the few that are following this Boredom Bowl, I will continue to post these uninspiring updates on my cooling system. I'll try to keep these brief until it's complete.
Hit the hi way yesterday for about 40 min's. This hi way has about 6 stop lights along the route and I kept it at 70mph+. Why this test? In reading one of the articles that Stephen posted it spoke of a head pressure build up on the pump. I had noticed this phenomenon early on but wasn't sure what was behind it. Heat or pressure? I used this MC filler neck in the front trunk and noticed a discharge after some hard runs so I poked a hole in the top of this water bottle to catch the overflow.

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It was only then that I noticed how much it discharged. No problem. I'd just pour it back in the expansion/recovery tank in the engine bay every once in a while. So now that I know why this happens I want to see if there is has been a change since the radiator swap. I didn't see any discharge w/ this radiator but I didn't "horse it" either. I'm betting 4000rpm+ and I will see it return unless this radiator flows more freely. 70mph is only 2800rpm.
So all this stromberg.gif and what did I learn? Just that the discharge is not constant. I may have the chance to "horse it" this afternoon to see if high rpm is related to that discharge. Seems logical that pressure would increase with rpm. If that's the case, and I suspect it is, I will change hose size. More later. beerchug.gif
914forme
QUOTE(Andyrew @ Mar 11 2016, 11:53 AM) *

Im going to be running the Davies Craig water pump and LCD control panel, it circulates both the water pump and fans perfectlg for speed and timing to maintain the desired temperature.

I got both for ~320 shipped from australia. Theres a link to the ebay auction/seller in my thread, ill get it in a bit.

headbang.gif

Nice, and it eliminates a lot of the items we are talking about in this cooling water pump cavitation.

Thermostat is gone, water pump is gone, and line sizes might be back down to a more reasonable size. Stock it uses 1-3/8" hose, accepts hoses from 1"-2"

I am thinking I am sold on this idea, Thank you Andrew for the tip.

Now to grind the impellers off a water pump.
76-914
We may all end up going this route but I had a pleasant surprise after yesterdays drive. I horsed it around on some back road twisties yesterday and did not have any discharge into the water bottle reservoir. Maybe a little in my pants as a Mountain Lion crossed the road in front of me but none in the water bottle. blink.gif Previously high RPM's preceded (not ready to say caused) this discharge. Absolutely no reason for this unless the newer radiator has < flow restriction than the old one. Maybe the 3/4" return IS ample. Regardless, it's time to throw the condenser back into the mix and see what happens next. beerchug.gif
76-914
No apparent changes to the indicated temp since throwing the condenser back on so I installed the Derale fan controller. The factory ECU was not shutting the fans down once they activated so I'm hoping this unit will produce favorable results.
It's quiet compact:

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Compared to my old Rat's Nest.

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Just needed to make this Tee for the sender and I was good to go. Look out Rt 66!

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914forme
Looking good, got to love progress!!!! I think you will be happy with that controller they work very well.
Chris H.
Nice work Kent. So simple. The stock system thinks too much doesn't it biggrin.gif ? Dang computers screwy.gif . I like how you can easily wire it to run all the time if you want with a switch. Nice for the first few days of the conversion too. Next time !
76-914
Thx guys and just as you you predicted Chris, the factory setting was way too low.
Chris H.
biggrin.gif Yeah it's easy to adjust. Mine was set at 165...and the controller is designed to turn off after the system cools down 10 degrees. So...highly unlikely the fans are strong enough to cool the system down to 155. They would stay on until the car was shut off. What are you gonna set it at? 185? 190? Just eyeball your gauge for the middle? I remember the SVX gauge stayed EXACTLY between C and H.
76-914
I've only adjusted it once so far, Chris. I just turned the screw until the fans shut down since the gage was centered at that moment. I'm not going to do any serious adjusting until it warms up a bit and the AC is in full swing. I can check temps with an IR thermometer at the copper tee later and dial it in. Yesterday, I discovered that an AC line was contacting the R side tie rod when the wheel was turned completely to the right so I rerouted those lines.
Chris H.
Alright, hose update. Got my 1.25 installed and all is well so far.

Kent here are some pics and info for your install:

Tips:

- The 1.25 is a STRETCH to get onto the radiator inlet/outlet but hot water and dish soap and they will fit. Might have the same experience on the engine end but be patient.
- The larger hose is not as bendy so keep that in mind when making turns, etc. Leave extra and then trim off a little at a time if you have a 90 degree turn.
- I had to X my lines because my hot line on the engine is on the passenger side and the inlet on the rad is on the drivers side. Do that in the front trunk if you have to, not underneath.

Up front:

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When you look underneath the car you will see that there very few places that the hoses fit through the steering rack. Basically if you locate the center of the steering rack (there is a bolt or something there), the hoses BARELY fit on either side. A lot of people just cut one hole that is oval/oblong shaped which makes sense. One will pass VERY close to the clutch setup, touching it most likely. That is the only route that allows you to easily line the hoses up in the recesses in the middle of the car.

Examples for you:

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See how tight the fit is there? There was an extra hole in the clutch plate so I zip tied the hose to it.

This shows both hoses from the other angle. You can see how they fit into the recesses (ALMOST exactly).

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The other alternative is to come out the sides of the front trunk but the steering gear is there and there could be interference. Maybe not I just didn't like the idea myself.

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To attach the hoses underneath I used these:

1.5" Rigid Conduit Straps

Even though they might seem too small, the recessed area makes it work.

To attach them I used the same bolts as before for the outer bolts (floor side) since they are lower profile. You can see them in the pic. For the inner ones in the tunnel I used 10/24 size with this HF threaded rivet nut tool

HF RIVETNUT

For 10/24 you need slightly larger than a 1/4" drill bit. Then hog it out a bit more and the insert fits in. Even though they are aluminum they seem plenty strong. When drilling in the tunnel the closer to the middle the better. Stay away from the seam between the two and it's highly unlikely you'll hit anything.

The system seems easier to fill and it has taken nearly 3 gallons so far. Temps are super cool but I haven't run it that long yet since I want to make sure it's full.

How's it going with the engine install? You get ant time this weekend? PM me with questions or call me.





Chris H.
poke.gif icon_bump.gif Update again!

I was able to start the car and let it idle for about 10 minutes. It wouldn't even get to 150 degrees with the 1.25 hoses. I know the gauge is dead on accurate since the sender is on the engine itself now. I'm running with no thermostat BTW, but more on that in my thread. You don't need to run that way. It does heat up more evenly.

KENT YOU'RE GONNA LIKE THIS UPGRADE!!!!
76-914
Not trying to be a post whore. Just needed to add this link re: the engine swap. beerchug.gif http://www.914world.com/bbs2/index.php?sho...=286795&hl=
76-914
I wanted to keep the std spec Serpentine belt from the beginning so that I would not need to remember what size belt to buy in the future. My first attempt was to block off the in/out ports on the pump. To do this I needed to disassemble the pump in order to remove the vanes. This worked fine for 7K miles but then the bearing gave out. I believe that w/o the vanes in place too much lateral load is placed upon the bearing from the belts tension. I had another pump and installed it but knew I needed to find another solution or go thru this again. This is my solution for the 3.0. I don't know if the set up is the same for the 2.5's but maybe. Material cost = ~ $60.

Remove the PS bracket then the PS pump from the bracket.

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Cut 2, 1/8" pieces of steel to fit the front and rear of the bracket. Note that the front piece should be radiused to clear the wheel. Hole locations are transferred from the bracket to the plate via hole centering punches. The bolt hole for the wheel itself is simple to locate. It is lined up vertically with the bottom bolt hole and 1/2 way between the 2 top bolt holes.The piece on the right with the piece of tube tacked on is the front piece.

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A view from the backside.

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Some pics of the front and rear pieces bolted in place. ***Note*** the bottom hole has an aluminum boss on the bracket the protrudes about an 1/8" out that needs to be filed down or the front plate will not fit flush!

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Add the necessary amount of washers to clearance the wheel from the bracket.

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Finally install the wheel.

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A few different pics showing the assembly in place and the clearance between the bracket and wheel. It's close but that is what is necessary to keep the wheel lined up with the belt.

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76-914
I've got about a 1,000 miles on the power steering bypass so I'm hoping it's good. I just pulled out my modified fuel tank and replaced it with an unmolested one. Thank you Chris H. You can see it cleaned up pretty good Chris. I'm now running a Walbro pump which I hope is a bit more robust than those Impreza pumps.

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Then I decided to polish the Fuchs after 2 years. I hadn't noticed the gradual degradation until I hit one with some Mother's. blink.gif Yea, the nuts look like Hell. I suppose I should get those into the plater this summer.

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Chris H.
Wow that did clean up nicely. A radiator shop did that for you? Looks great. So you're up and running with the Walbro? Simple is better with that IMO.
914forme
I have done them both ways, and I prefer a Walbro in the tank, keeps it nice and cool, and well, makes it a bit more quite. But then, It is nice hearing the fuel pump running. When I raced I had a simple dash switch for it. Also allowed you to cycle all the heat soaked fuel out of the lines for that 100HP boast you get from cool fuel. huh.gif

It might really be a 0.001 HP improvement.

Yes I want to know what the Rad Shop used, as I have two tanks to get cleaned up, and sealed.
76-914
QUOTE(Chris H. @ May 27 2017, 09:14 PM) *

Wow that did clean up nicely. A radiator shop did that for you? Looks great. So you're up and running with the Walbro? Simple is better with that IMO.

This radiator shop mainly does large heat exchangers used in HVAC industry. I didn't unwrap that stinky tank to inspect but he confirmed your appraisal. He said it was in great shape with that one little spot so that's why it was treated. What impressed me was that he knew it was a 914 tank. He said the aftermarket Stereo Installers created lots of work for him in the 70's. av-943.gif I know this is my imagination working overtime but I swear I have more power now! Is that possible? My pressure is up by about 2psi at cruise and 6psi when floored. WTF.gif

QUOTE(914forme @ May 28 2017, 07:26 PM) *

I have done them both ways, and I prefer a Walbro in the tank, keeps it nice and cool, and well, makes it a bit more quite. But then, It is nice hearing the fuel pump running. When I raced I had a simple dash switch for it. Also allowed you to cycle all the heat soaked fuel out of the lines for that 100HP boast you get from cool fuel. huh.gif

It might really be a 0.001 HP improvement.

Yes I want to know what the Rad Shop used, as I have two tanks to get cleaned up, and sealed.
I'll ask him what they used if you'd like, Stephan. The reason I went with the external pump was to see if the old pump was heating the gas. My gas tank was getting hot as Hell so I wanted to see if the pump or the radiator was heating the gas. The 914 tank is not exposed to the cooling air rushing beneath it like a regular tank. My thought was: if the tank can't shed the heat from the pump how will it cool the pump and not continually heat the gas? I'm probably wrong as usual but I'll figure it out eventually. One thing I've learned over the years; When faced with inexperience tenacity is your best friend. beerchug.gif
914forme
[quote name='76-914' date='May 29 2017, 11:56 AM' post='2490750']
[/quote] I'll ask him what they used if you'd like, Stephan. The reason I went with the external pump was to see if the old pump was heating the gas. My gas tank was getting hot as Hell so I wanted to see if the pump or the radiator was heating the gas. The 914 tank is not exposed to the cooling air rushing beneath it like a regular tank. My thought was: if the tank can't shed the heat from the pump how will it cool the pump and not continually heat the gas? I'm probably wrong as usual but I'll figure it out eventually. One thing I've learned over the years; When faced with inexperience tenacity is your best friend. beerchug.gif
[/quote]

Some cars actually use a fuel cooler to help dissipate heat. I would not want to run the fuel line down the side of the car, but one way to dissipate the heat would be do the same thing, and just run a coil in front of your rad. Fuel heat can become an issue, as we all know from Vapor lock.

I would start placing a temp probe all over the place before I went to the problem of a new pump. I have a feeling your picking up heat soak off your cooling system. Dissimilar temperature items like to merge to a constant stable temperature. Only way to know is to test. I ran a rotary fuel pump mounted to my 911 cross bar about the gravel tray for years with out issue, it was just loud.
76-914
Well good to know you and others have experienced this Stephen. I'll report back after the WCR event. If it is still an issue I'll duct the radiator to the wheel wells. I've been tossing around the idea of a canvas duct! idea.gif beerchug.gif
76-914
As promised, the results from the WCR trip. I was wrong again. After I eliminated every other possibility things finally make sense. First I want to say why I was adamant that the radiator exhaust wasn't the culprit. I had over 5000 miles on the car before the gas tank began to have this heat soak issue. But in thinking back, I changed radiators March 2015 which is when all this began. I never had this problem with the single core but once I went dual core........whamo! WTF.gif While you wrap your head around that I'll go on to mention that I'm not the first to experience a hot gas tank. I talked with Tony aka Cracker @ WCR at length about this. That's about 5 minutes for a drunk. av-943.gif Anyway he shared some of his past experiences and several of his ideas on this. Before ducting the radiator shroud I decided to take his easiest suggestion; enlarge the openings in the wheel well. Well wait just a damned second..........doesn't this tie right back in with where I left you......why this began with the radiator change out 15 month's ago. These are my thoughts and I'd like to hear yours on this. To quote Cap't Ron, "Now stay with me...." I believe the Celica racing dual core lets more air pass than the old single core Scirocco would did. This excess hot air now looks for other ways out. One of these is past the bulkhead seal, around the tank walls and out the opening below the steering column. Yes, I have the cover in place but it's certainly not air tight. Below are the pics showing the taped border area where I cut to enlarge the opening in the wheel wells. I'll drive it until I can determine if it is cured. If not then the radiator hoses get rerouted beneath the car and a plenum shall be made. More on this later. I'm coming up on 10,000 mile and believe this albeit the most recent problem, is the last of my Gremlins. beerchug.gif

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Chris H.
QUOTE(76-914 @ Jun 11 2017, 10:21 PM) *

I'm coming up on 10,000 mile and believe this albeit the most recent problem, is the last of my Gremlins. beerchug.gif



Don't even SAY that out loud! biggrin.gif

Consider wrapping the hoses that are in the front trunk up high with something like this:

Aluminized sleeving
rhodyguy
Now you jinxed the whole deal. slap.gif
Chris914n6
QUOTE(76-914 @ Jun 11 2017, 08:21 PM) *

That doesn't look like it's enough. Would be worth it to crunch numbers. The OUT needs to be 20% larger than the IN to account for heat expansion of the air.

An insulator between the hose and the tank might help. I don't think the heat transfer would be THAT much but it's possible.
Andyrew
QUOTE(Chris914n6 @ Jun 12 2017, 02:45 PM) *

QUOTE(76-914 @ Jun 11 2017, 08:21 PM) *

That doesn't look like it's enough. Would be worth it to crunch numbers. The OUT needs to be 20% larger than the IN to account for heat expansion of the air.

An insulator between the hose and the tank might help. I don't think the heat transfer would be THAT much but it's possible.


I thought it was 50% larger?



I think you probably could use with a larger outlet for your radiator, but JUST ducting it will certainly increase your efficiency by a wide margin methinks.


Could be a fun foam or cardboard adventure depending on how you shroud it smile.gif
Chris914n6
QUOTE(Andyrew @ Jun 12 2017, 04:02 PM) *

I thought it was 50% larger?

Just 20%. A bunch of engineering went into my AC unit, some was actual heater core and radiator temps and air volume.
76-914
QUOTE(Chris914n6 @ Jun 12 2017, 02:45 PM) *

QUOTE(76-914 @ Jun 11 2017, 08:21 PM) *

That doesn't look like it's enough. Would be worth it to crunch numbers. The OUT needs to be 20% larger than the IN to account for heat expansion of the air.

An insulator between the hose and the tank might help. I don't think the heat transfer would be THAT much but it's possible.

The in would be the air inlet, correct? That area is 18 x 5 or 90 sq in. The new cutout area will be 180 sq in. The coming 15 days will be hot so I'll see what happens with the larger openings. beerchug.gif
mgp4591
QUOTE(Chris914n6 @ Jun 12 2017, 05:45 PM) *

QUOTE(Andyrew @ Jun 12 2017, 04:02 PM) *

I thought it was 50% larger?

Just 20%. A bunch of engineering went into my AC unit, some was actual heater core and radiator temps and air volume.

I'd always heard that it's twice the outlet size per inlet size... idea.gif
76-914
QUOTE(Andyrew @ Jun 12 2017, 04:02 PM) *

QUOTE(Chris914n6 @ Jun 12 2017, 02:45 PM) *

QUOTE(76-914 @ Jun 11 2017, 08:21 PM) *

That doesn't look like it's enough. Would be worth it to crunch numbers. The OUT needs to be 20% larger than the IN to account for heat expansion of the air.

An insulator between the hose and the tank might help. I don't think the heat transfer would be THAT much but it's possible.


I thought it was 50% larger?



I think you probably could use with a larger outlet for your radiator, but JUST ducting it will certainly increase your efficiency by a wide margin methinks.


Could be a fun foam or cardboard adventure depending on how you shroud it smile.gif

See that pink string, Andrew? That is the forward/top corner of the proposed duct. Doesn't give me a Hell of a lot of room to tie in the shroud but doable. I laid out some measurements in case I need to duct. I've a couple of cool ducting ideas, I mentioned canvas earlier, that I will bounce off you guys if it comes to that. This is going to get handled and put to bet this summer. beerchug.gif
Chris914n6
QUOTE(mgp4591 @ Jun 12 2017, 08:45 PM) *

QUOTE(Chris914n6 @ Jun 12 2017, 05:45 PM) *

QUOTE(Andyrew @ Jun 12 2017, 04:02 PM) *

I thought it was 50% larger?

Just 20%. A bunch of engineering went into my AC unit, some was actual heater core and radiator temps and air volume.

I'd always heard that it's twice the outlet size per inlet size... idea.gif

That guy was blowing smoke up your ass. The formula for thermal expansion is on the internet if you want to do the calculations. I think any further discussions of this should be in a separate thread.

The hot air would have to be blowing past the trunk seal to heat the gas tank as the tank doesn't actually touch the metal divider. Opening up the truck holes to 2x inlet air should alleviate that if it's the problem.
Chris H.
This is what concerns me if the tank is getting hot. The hoses are very close to it on both sides. Can't hurt to wrap those with some insulated wrap or sleeves.


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76-914
QUOTE(Chris914n6 @ Jun 12 2017, 09:18 PM) *

QUOTE(mgp4591 @ Jun 12 2017, 08:45 PM) *

QUOTE(Chris914n6 @ Jun 12 2017, 05:45 PM) *

QUOTE(Andyrew @ Jun 12 2017, 04:02 PM) *

I thought it was 50% larger?

Just 20%. A bunch of engineering went into my AC unit, some was actual heater core and radiator temps and air volume.

I'd always heard that it's twice the outlet size per inlet size... idea.gif

That guy was blowing smoke up your ass. The formula for thermal expansion is on the internet if you want to do the calculations. I think any further discussions of this should be in a separate thread.

The hot air would have to be blowing past the trunk seal to heat the gas tank as the tank doesn't actually touch the metal divider. Opening up the truck holes to 2x inlet air should alleviate that if it's the problem.
Chris, feel free to download any info you feel pertinent to this problem. It it saves someone headaches, time and $$$, do it. agree.gif w/ the 20% rule as this is what I've read, as well. The hot air is blowing past the seal. Or what's left of it. I did trim it to allow the hoses to pass over the firewall. Even the unmolested seals let air pass by the ends of the seal. The hot air is then drawn down along the sides of the tank on its way out the steering column cover. My cover has half of a small butane tank welded in to cover my first attempt at a clutch master cylinder. I believe this exacerbates the problem. Kinda like blowing across the top of a Coke bottle causing a bit of negative pressure. Anyone have an extra cover for sale?? beerchug.gif

QUOTE(Chris H. @ Jun 12 2017, 09:43 PM) *

This is what concerns me if the tank is getting hot. The hoses are very close to it on both sides. Can't hurt to wrap those with some insulated wrap or sleeves.
I've touched both the hoses as well as the fuel pump when it quits and they aren't that hot. confused24.gif You might be right, though. Changing those out and ducting is next on the list if this doesn't do the trick. beerchug.gif


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914forme
QUOTE(Chris914n6 @ Jun 13 2017, 12:18 AM) *

QUOTE(mgp4591 @ Jun 12 2017, 08:45 PM) *

QUOTE(Chris914n6 @ Jun 12 2017, 05:45 PM) *

QUOTE(Andyrew @ Jun 12 2017, 04:02 PM) *

I thought it was 50% larger?

Just 20%. A bunch of engineering went into my AC unit, some was actual heater core and radiator temps and air volume.

I'd always heard that it's twice the outlet size per inlet size... idea.gif

That guy was blowing smoke up your ass. The formula for thermal expansion is on the internet if you want to do the calculations. I think any further discussions of this should be in a separate thread.

The hot air would have to be blowing past the trunk seal to heat the gas tank as the tank doesn't actually touch the metal divider. Opening up the truck holes to 2x inlet air should alleviate that if it's the problem.


confused24.gif if Kent only needs 20% that is an extra 36 sq inches based off his quoted inlet size of 180 sq inches.

So why are you suggesting he adds an additional 180 sq inches to his current 180 squar inches to create 360 squar inches of outlet. Which so happens to be a 100% increase. Or 2x the opening size from the ratio of inlet to outlet. And you said the person who recommended that was blowing smoke up Kent's ass. Then you went and blew the same smoke up his ass confused24.gif It might have been a different color but it all smells the same stromberg.gif

Kent your issue is not enough exit. Ducting will help as what you are doing right now is like trying to corral free range cats. It just can't be done. Much easier to domesticate the poor bastards then push them down a narrow shoot. So go out and add duct work, or add bigger holes. Or remove them little fans you got there, and add some duct work and a small snowmobile engine. Use it to drive a turbine fan, and make your car into a sucker car.

Then you have no problem getting them pesky cats rounded up. And everything else in your path will be sucked up and spit out in a million little pieces. Of course you could then take this turbines outlet air, and duct it into your intake, and well then you have your self a supper charger shades.gif

Now you have created a whole mther set of problems to figure out, but you solved your cooling issue, in a very golbergian fashion. av-943.gif
76-914
I'm thinking your right Stephen but hoping your wrong. I'm prepared to duct it but thought I'd try opening up the wheel wells a bit first. BTW, I think Chris was saying that 20% is the rule but if I was going to increase the opening by a factor of 2 I'd be just fine. How's your project coming along? Kent beerchug.gif
mgp4591
QUOTE(76-914 @ Jun 14 2017, 08:11 AM) *

I'm thinking your right Stephen but hoping your wrong. I'm prepared to duct it but thought I'd try opening up the wheel wells a bit first. BTW, I think Chris was saying that 20% is the rule but if I was going to increase the opening by a factor of 2 I'd be just fine. How's your project coming along? Kent beerchug.gif

I think 20% additional is only 36 sq. inches... and I really wouldn't want Chris to blow smoke up my ass... blink.gif if I want it, I'll pay someone else to do it in Vegas... happy11.gif
76-914
I've put this off for long enough. I tried driving "the proverbial" square plug in a round hole long enough. I should have done this long ago but chose to eliminate the other possibilities first. My mistake. mad.gif
Before I go on I want to pass on a condensed version of my thinking and failures leading up to this. If you didn't already know, my gas tank has been getting hot and manifesting itself into at least two other problems. There may be others that haven't reared their ugly heads yet. When the tank reached "X" temp i.e. hot to the touch I could feel the metal dash and it would be hot. This in turn made it damned uncomfortable to ride in any ambient temp greater than 40F. Within minutes of feeling the hot air emanate from the dash the fuel pressure would drop from 42psi to less than 10psi at which point it would stall. After letting the tank cool down I would repeat the process. headbang.gif
What confused me was that I had nearly 5000 miles on the Odo before this problem surfaced. idea.gif Hmmm. What could have happened that might have caused this? I remembered changing the fuel pump after it conked out and immediately surmised that the new pump was heating the tank. Why didn't the old one do this? I don't know and failed to ask myself this all important question. screwy.gif My solution; change out the heavily modified 914 gas tank and replace it with a stock tank and larger Walbro pump to meet the 3 liter'e appetite. I completed that change about 1 week before WCR2017. I've learned not to put much faith into my diagnostic abilities so I towed the 914 to WCR. Good call because my efforts were in vein. Just ask Wes. We sat in the heat on the side of the road for 2 hours whilst it cooled. Thank God I wasn't carrying that day or I'd have taken that SOB out back and shot it.ar15.gif Back on track. What changed that caused my gas tank to heat? idea.gif Then I remembered and as posted here earlier, I had changed from a single core Scirocco radiator to the favored Celica dual core racing type when this "heated gas tank" conundrum began. Btw, that is a Hell of a good radiator. In error I believed the newer radiator was more free flowing and allowed more heat to saturate the tank but that thinking was flawed. The same amount of heated water at "X" temp was passing thru the new radiator as the old. I now believe (or should I say, "This time I think it is.....) it was a simple matter of inlet area > outlet area. When I drilled out the front wheel wells I made the exhaust area 40% larger than the opening for the radiator. Right before I changed out the radiator I increased the inlet opening hoping for some relief from over heating. For some reason this evaded the limits of my memory until this weekend. headbang.gif
No loss. I'm ducting this thing and putting it to bed once and for all. In order to duct the radiator I will have to make a couple of PITA changes. The first change I've been anticipating. Change out the radiator lines that presently run thru the longs in favor of the bit larger 1 3/8" hose fitted beneath the car. The second will be rerouting or replacement of the AC lines in the frunk. These 2 things will clean up the frunk allowing the duct. I had bounced around a few ideas on materials and ultimately settled on Aluminum for all the usual reasons. I still had a few sheets of 2024 laying around so I decided to start throwing some metal at it. I have some E Glass on hand but I believe it will ultimately be faster to Fab it than Dab it.
This is where I'm presently at. My target outlet area is 180" sq.;90" sq per side. This is a pic of my template.

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Left side roughly outlined with some tape. The wire looms are very close to the lower left corner but should work.

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Right side. Same thing except I've got the AC hoses to deal with here. Notice the AC bulkhead fittings at the lower right corner? outlet frame is beginning to take form here as well.

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And a few more with the side attach pieces mounted to the radiator outlets. This design will have two plenums. One for each side. More pic's to come once things cool down here. 105F yesterday; 103F today! happy11.gif

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914forme
Why divide the center? Just wondering are your fans staged? I think your making this a bit to complicated.

But then that is the pot calling the kettle black. av-943.gif
76-914
Baby steps. It happens every time I design and build simultaneously. headbang.gif
Paper template for bottom tray piece being fitted:

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The bottom piece now cut, positioned and clecoed in place.

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The piece in front of the radiator hose connection is an access cover and will be held in place with SS screws rather than rivets. The top piece which will be removable for service and access is next. It will surely by a Royal PITA as there are multiple angles that need to meet. sad.gif

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