I just got my nose cut and the radiator installed in my Suby conversion. While I build the air duct box I must consider how to get coolant lines from the engine bay to the front trunk.

To be track legal I do not want them inside the passenger compartment.

what are the options? here are a few I can think of. Let me know your experiences. Links to specific install threads would be great.

1. Run lines through the rockers. Where do you exit? Do you follow the current duct through the bulkhead or cut holes through the floor?

2. Run lines under the car. I can use the two recesses that run through the center tunnel. I really don't want the lines under the steering or suspension.

3. Run the lines under the outer rocker panels. With some reinforcement I could open up the center of the support triangle. The issue is getting clearance around the jack tube.

Let me know your experiences. Links to specific install threads would be great. Do you have a site or thread build detailing the install. I have sifted through the archives but could not find what I was looking for.

Big fat no on nubmer 1 mine is thru the rokers and is horrible, the hose exit thru teh speaker grill area and when it leaked, my feet got soaked in hot water!!!
near imposible to run thru rockers with out cuting up the rocker to feed thru, worst place wil heat up teh car bad to also


best place (that i will get done ) is under car use rubber hose ther, use gates grren strip hose, as it is touogh and can take bottom out scrapping and be fine (metal pipe is bottom out will be crushed!!!) simply easy cheap an best

I ran steel lines under the car in the recesses of the floor pan

Click to view attachment

Rockers and other sheet metal are lower than the coolant lines. To crush them it would be really difficult.
More pictures at:

http://www.phoenixhobbies.com/html/cooling.html

Paul

I was considering a single hose run all the way through the rockers. I would not have any junctions and therefore leaks should be minimal. Great point about the heat. Its hot enough in TX. I don't need to fuel the fire.

Paul Thank you for the pictures. Great install. Can you tell me how you entered the front trunk area. It was not clear from the pictures on your site.

Jamie,
I am in the process of running mine thru the rockers. I have one run so far. I really hope heat isn't too much of an issue...... It wasn't too bad removing the metal sleeve and insulation from the rockers. I went thru the opening closest to the engine bay with needle nose vise grips to get the metal wire out.

Oh, I am also in Austin (Cedar Park), so good to see another Austinite on here. Let me know if you want some pics.

Cheers,
Colin

Lines run between the front cross member and steering rack and enter the front trunk (circled in red)

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Great! Thanks for the description. There should be quite a bit of room in there. I will do a bit more exploration tonight. I will bring mine out on the Pass side since that is where my radiator connections are.

I like how these are kept low such that they do not trap air. The conduit should be easy to source. Did you bubble flare the end to prevent the hose from coming loose? I don't think the pressure is high enough to need it.

I used Stainless tubing and brazed a 1/8" wire ring around the ends about 1" in

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After meeting with Renegade in Las Vegas last year, I have decided to follow their lead and run rubber hoses under the car. Renegade recommends against running the lines in the rockers due to up/down/up of the hoses, which apparently makes it very difficult to burp out air bubbles. I don't have any real-world experience with that issue, but it makes sense to me...

They also recommend against steel tubing due to the crushing issue -- they recommend keeping a hose mend kit & a short section of rubber hose in the car in case you go off track and rip a hose. At least you can get home that way; it would be difficult to make a field repair if you crush a metal pipe.

Geoff

Ran mine through the longituditals with a continuous length of Green stripe hose. It follows the existing heat duct routing. Being that it's continuous, there shouldn't be any concern about leaks into the passenger compartment and being that it runs through the insulated heat ducting in the long, the heat radiated into the passenger compartment is minimized.

Biggest problem is getting the hoses past the fuel tanks - tight squeeze but it can be done. I really wanted to avoid running under the car. I've got a Cobra with 4 1/2" ride height and I have to be very careful around any speed bumps and steep driveways. Hoses tucked away and I don't even have to think about them.

Tom

I ran mine outside the the car along the longs. right now the lines are made out of 1.25" copper, with rubber between the copper and the radiator etc, however i would love to do bent aluminum tubing in the future. to get to the front trunk i ran the lines around the inside of the wheel wells, and through the cut outs for hot air to escape. They follow the curves of the car, and have no clearance issues. At the high point of the lines i put shrade tire valves to help bleed air out of the system. So far it has been flawless, and i have no problem getting the air out of the system. it takes about an hour the first day, and a couple minutes the week after to top off and bleed the system a little more. I am also planning to do custom rocker panels to completely hide the lines.

Thank you for the additional replies. There is some great information.

Tom, Do you think the interior gets really warm with the coolant lines running through? Do you have any issues with left foot clearance where the DS exits and goes forward?

tbox, Do you have any pictures. This sounds just like the external oil cooler lines on my 911. Did you use soft copper and roll to shape? I suppose that some Adel clamps would easily hold it in place.

I pulled the gas tank so that I would be able to pull through this area.

Currently I am leaning towards the hard lines following the recess under the floors/center tunnel. This is purely a matter of cost.

I've had 2 V8-14's.

First one had rubber coolant lines inside the tunnel. This cooled well but put a bit of heat into the cabin.

Second one has rubber hoses under the car, in the recesses next to the tunnel. This cools very well too. The hoses go under the steering rack and enter the front trunk theough the factory access holes. The problem here is the mounting clamps. The get slightly crushed from speed bumps and need to be reshaped a couple times per year.

The best one I've ever seen... rectangular tubing run in the recesses under the car. Hung down less than 1 inch. The owner capped the ends of the tube and welded vertical hose barbs at the trunk and engine. This install was super clean.

The risk of hard lines is due to ground clearance. If you go over speed bumps too fast you can chrush round tube. The square tube has more ground clearance. Do not ever use copper under the car. Copper is too soft and can rip apart on a speed bump. I have seen copper inside the tunnel the looked very clean, however, copper is an excellent heat conductor and will put to much heat into the cabin.

Now you could get Aluminum Schedule 40 conduit from an electrical wholesale house. It has a thick wall and is ridgid. Can be threaded. This could be run in the tunnel and have less heat impact in the cabin

aluminum and copper are both pretty good heat conductors but even my rubber hoses put way to much heat inside the cabin when in the rockers.

the Gates (I think it is called green stripe) hoses is very tough, thick and re-inforced no corrosion issues is a bonus. but run it under the car. that is what a major conversion company is now doing. You can get this "bullet proof hose from hot rod shops or West Marine supply

rubber is just fine, even if it did get draged on a bump, face it, youtires are made of rubber, and this stuff seems to be near as tuff as tire rubber.

the risk of a show stopping cruch of a metal pipe is too much for me, plus the rubber hose is very very easy to bend to fit verses a metal pipe!
easy install, and tough and a decent price, cant beat that, plus under your car you have no worry at all of leaks getting in the cabin nor the excessive heat, my little V6 car dumps way to much heat in the cabin with the hose in the rockers,

plus you will need some right angle metallic couplings to transition the hose from teh heater channel up thru behind the speaker grills followoing the path of the old paper heater hoses, that is a source of leaks, and you will be then routing you hose up over the dash near teh fuel tank, and you will need more anlged metallic couplings to make the needed bends up there, again leak potential, and that hot water, even though behind the dash int eh gas tank area will still drip (or gush) down on your feet if it fails via the many penitrations under the dash.

try to keep it all under the car with tough rubber, valid points were made about bleeding air out with the behind the dash route. you will want to add multible bleed valves otherwise (royal pain) yes the wheel well option will work too, however you have to keep teh pipe close and tight to avaoid tire rubbing (make extra room for future bigger tires)

pay very care full attention to pipe diameters, dont go too small or you will have flow issues, this is a long run, too small a diameter with too powerful and engien will spell probelms (plan ahead for future is you ever want to pump up or upgrade you water cooled motor, you want ot make sure you cooling lines are already big enough. go over kill in diameter as much you can.


200F fluid circulating inches form you feet is not a nice thing on a hot day ever.

I used 1" bellows-flex hose you can't kink it and ran it in the longs up to the trunk under the gas tank and in to the front trunk to the radiator. I don't get any heat in my cab. I just can't see how guys claim this ? No offense intended just puzzled. The hose runs through a pipe in the rockers which is then surrounded by air and then loads of steel and carpet OH well who knows... So far so good 4 years later.

i claim it cause when I put my hand on that door sill carpet, it is hot. if hose runs up behind the speaker grill there is little steel or carpet around it, and that too is hot.

Funny you mention the square tubing. That was my idea as well although I did not post it. I thought you could build an X brace across the floor and run coolant through the tubes. This would solve some chassis stiffness problems as well. However, the pivot points are much higher than the floor so it may not impact chassis rigidity as much.

I do agree that square tubing would hold up to impacts and have less clearance issues compared with round.

Since I am building a GRM $2010 Challenge car I have to pay close attention to the cost of these coolant lines. My 75 is getting a WRX engine.

Whatever you decide, buy a radiator leak test tool. This will allow you to pressurize the system and find leaks. I recommend 16lb caps for the system with a catch/recycle can.

If you can afford a vacuum pump ($250 for a good one), this will help get the air out of the system. I have a petcock at the highest point of the system. I draw vacuum through a sealed vessel connected to the petcock. The vessel keeps the water out of the pump. Pinch off the overflow hose and draw as much vacuum as possible on the sealed cooling system. Connect your overflow hose to the bottom of you catch can and fill the can with water. Once you have pulled max vacuum, open the overflow hose and let the system draw in water. Do this several times and you will get all the air out. If you use clear hose for the vacuum you will see either bubbles or water comming through. Stop when you only get water.

Also as mentioned in other radiator plumbing posts you might want to google electrolysis between aluminum motors and stainless steel cooling tubes. The fiero uses ss tubes but it is a castiron motor.

This is the nicest routing I have seen so far. It's Carreraguy's swap.
Blog He says no heat issues at all. I am trying to see his car - he lives nearby.
Steve

Top Notch...Renegade. Probably not a good idea for a tunnel with mechanical linkage...only if you're going with a cable shifter.

I think it was done at Jerry Woods race shop..

Bob

I do have a pic of my setup... Keep in mind it is not finished and only in place for "applied testing" right now, but have run into no poblems with it. The coolant lines are not the lowest part on the car, so i don't have to worry about bottoming out on a speedbump or anything... I have since made rubber isolated brackets to replace the beautiful bailing wire... As you can see i used sweated copper fittings to make the bends, 2 45s to make a smoother curve than you can get with a 90...
Click to view attachment

We have a winner! You are correct. BTW where is this shop? I am in Campbell and I think I am within walking distance.
Steve

I won't say you didn't feel the heat,

but really if we extrapolate further we're not far from the headers ether. My point is there is 400 pounds of hot steel inches from our backs but I don't have a hot firewall. I do have lots of insulation and my engine always runs under 200 degrees. BTW I do have A/C as well.