Split Front Mounted Radiators

[Fraser D]

Thought it best to start a thread specifically about the progress and the modifications being made to install a split radiator system in the front of my GTM. Feel free to chime in with suggestions, comments, etc and I will try and be as detailed as possible with the modifications so that if everything works out the way that I am planning it will, fellow builders will have a good understanding to either copy or deviate from what I have done.
Please this is specifically about a front split system and not about installing radiators anywhere else on the car.
After the initial mockup I was able to determine where there was room to mount each radiator with enough clearance between the tire and the radiator itself. I did look at similar setups on production cars and was surprised how little clearance they were running between the tire and the radiator protection.
As with most modifications like this there is going to be a little trial and error.

[Fraser D]

The maximum available space was 18” tall x 15” wide which when doubled has the same surface area as the original Corvette unit.
I ended up purchasing this radiator knowing that the top inlet would need to be resized and moved while the cap will be removed in order to give enough clearance behind the headlight bucket.
The radiator is;

Overall Size: 14.37"x16.5"x2.5"
Core Size: 13.5"x16.5"x2.25"
1.25" Inlet & Outlet
3 Rows

Radiator Fan Spec:
Size: 12"
Thickness (Motor Height): 2.5"
Air Flow Rate: >1130 CBM/Hr
Speed: 2100 RPM
Power: 12VDC, 40W

[Fraser D]

The radiator is just sitting in place to give me an idea of what is going to be in the way.
The top fill tube will need to be moved to clear the back of the headlights and it looks like the radiator will need to be angled back a little as well due to the headlights.

[crash]

As I said on the "other" forum, just flip the radiator around, and your clearance problem will disappear. Probably also much more efficient routing of the lines this way as well.

[Fraser D]

Crash,

I am trying to keep the thread going on both forums so bare with the repeats.
While that helps with the top it does not with the bottom hose, but you bring up a good point about there being more clearance at the top due to the curvature of the wheel well. The top facing into the wheel well and against the frame and the bottom facing forward may be the cleanest solution.
It will not be hard to make the radiator guard curved to match the wheel somewhat.
I still need to play around a little this week if I have time, but relocating and resizing the ins and outs is not an issue as I have a TIG set up in my garage and enough ally stock to completely replace the tanks if I need to.

[crash]

As I said on the other forum, be ultra careful if the tubes are epoxied, as opposed to brazed, onto the tanks. They can be ruined easily from the heat of TIG welding.

[Fraser D]

Crash,

Thanks, understood regarding radiator construction and heat issues.
Stay tuned for photos of success or spectacular failure in a couple of weeks when I am allowed back in the garage to play!

[Fraser D]

IMG_0186.jpgIMG_0194.jpgIMG_0196.jpgIMG_0197.jpgIMG_0200.jpgSnuck a couple of hours in the shed today and was able to make progress on the fabrication of the radiator mount. It is starting to look the part and I have been able to maintain clearances from the front wheel and the headlight connectors. The next challenge is mounting the condenser but I have verified that it does fit… just.

[crash]

Looks cool.

[Fraser D]

IMG_0244.jpgIMG_0242.jpgIMG_0247.jpgDrivers side mounted, now for the ins, outs and the condensers.

[Fraser D]

A small step forward today.
Passenger side radiator TIG'd together, (man I am out of practice with this welder) and have started on the driver’s side.
I think that I have the plumbing configuration sorted out and in the process realized that I have the tunnel tubes back to front. Correct as per the manual but not correct as per pump flow. I have 1 1/4" to the passenger side and 1 1/2" to the center of the tunnel. So I am debating if this actually makes a difference but will most likely nut up and take the hour or two to swap them.
The coolant flow will be coming into the bottom of both radiators and out the top.
Between getting rid of the original stainless hoses and using an engine bay header tank, getting the battery in and out is not too much of a struggle.
Currently looking for a Houston AC guy who can make up custom AC hoses for my condensers.

[kabacj]

Looking good Dave! That setup is will really open up the styling options for the front of the car. Keep up the good work.

John

[Fraser D]

John,

Thanks. I just think that the GTM front looks a little unfinished so let’s see if I end up making it better or worse ;-)
I am hoping to get the cooling system back together this weekend and go for a drive to see how the temp sits before the hood goes back on.

[mendo]

I think the flow should be "in the top, out the bottom". that way the pump always has water to suck.

[Fraser D]

Mendo,

I was initially concerned about getting all the air out of the system but I guess that with once the system has been purged there is no reason for the "in at the bottom, out at the top" orientation. With an engine bay header tank and an air bleed at the high point for each radiator there should not be trapped air issues so pump supply can be the systems priority.
Thanks and I appreciate the input.

[crash]

I concur. Hot water should be at the tops, and chilled water should come from the bottoms.

[Fraser D]

I concur. Hot water should be at the tops, and chilled water should come from the bottoms.

I sure am glad you guys pointed this out before I cut up my tubing.
Thanks

[Fraser D]

Radiators welded up, (starting to get the hang of TIG welding again) and piping run. I hope to get the header tank installed and radiator tubes beaded tomorrow so that I can start the engine to see if I have any leaks and if there is any difference in temps.
Once I know that there are no leaks I will frame out the trunk, mount the AC condensers and fans then tidy up the battery area.
Then the body mods start in earnest.

[Fraser D]

Ran the car around the block a couple of times this afternoon with only one small leak found.
Car temp ran about where it normally does but I don’t have the hood, ducting or fans set up yet so it is a little soon to tell if there is going to be any benefit or issues. The header tank set up made removing the air from the system very easy and I don’t believe that I had any vapor locks in the plumbing as all seemed to be getting varying degrees of warm.
Next is to fix my leak, do a little tidying up and make the debris guards between the radiator and the front wheels.
All in all a positive move forward today.

[kabacj]

Looks great Dave. Very neat install.

John

[Fraser D]

Thanks John, It's all starting to come together
Just a quick video of the first test drive with the split radiators.
I will tidy up the plumbing this weekend and install the wheel guards if the material is delivered in time.
Once the hood is mounted, secured and modified the radiators will be securly braced and connected to ducting from the front of the car.
http://youtu.be/31zo3FPyV4k

[Fraser D]

Well no leaks and no heating issues after a little spin around the block and a long run in the garage with the hood on and the hatch and glass installed.
Time to start mounting and modifying the hood.
The material for the wheel guards has not arrived yet so that will be next weekend’s task.
First go with the Go-Pro taped to the roof and an unsuspecting father-in-law who did not know that I was recording ;-)
The car is struggling to hook up well with the old set of 295’s on the back and a very rough chassis set up.


http://www.youtube.com/watch?v=G0c6ijqGqQ8

[Fraser D]

Two weeks ago I found a couple of spare hours to get the AC condensers mounted but not plumbed up.
I need to find some fittings compatible with the Honda Civic DelSol condensers and make some hoses.
The lower driver’s side radiator outlet needs to be moved inboard as it rubs on the hood.
I think that I will try the stainless steel mesh as the tire guards as I was not happy with the aluminum honeycomb that I picked up.
Mesh spec from McMaster Carr
9253T482
Extra-Rigid Type 304 Stainless Steel Woven Wire Cloth, 1/4" Opening Size, .063" Diameter, 24" X 48" Sheet

There is still lots of work to do with securing the tubing and bracing and detailing the mounting frame.

[Fraser D]

I have made a bit of a step back from my original design layout.
Spoke to a friend who is all about air movement and he pointed out a fundamental flaw with my original layout.
It is called roping.
In a nut shell I was loosing approximately 1/3rd of the radiator area due to the boundary layer of air created by the tire's rotation.
That boundary layer in theory would push air back through the radiator effectively stalling air flow through that portion of the radiator.
This set up may just work but I am not willing to take the risk with the changes that need to take place with the body,
I had originally avoided cutting up the chassis to install a different profile cooling system but now all bets are off.
I will be installing a pair of AFCO Racing Scirocco-Style Drag Racing Radiators 80107N set at an angle.
The original set up will work for a lower HP setup but mine will be 550-750hp
More photos to follow as I mount the radiators,
Hopefully this will be the reliable solution.

[Desertrunner]

I did not know you could do this, what gets me why don't you end up with holes in the radiator from stones etc being thrown up from the tyres.

Don't get why it would not have been better to tee the radiators so each operated seperatly, would have been less pressure loss in the system and also long residence time, slower veliocty in each radiator.
As for the need to send hot in the top and cold out the bottom, its a over stated benfit. In most cars the volume of the radiator is changed every 6 secs. That means there is no time for convection to work or have any effect.

Nice set up, well done.

Tony

[Fraser D]

Tony,

Guarding is still needed between the radiator and the wheel to prevent damage.
When you look up in the wheel well of most vehicles you will notice that there is very little/if any indication of debris strike in the front half of the wheel well.
Whatever has been picked up by the tire has been flung off in the first 200+ deg of rotation for the most part but there will always be that pesky little stone that did not take jnr high physics but is well schooled in Murphy.
As for the flow path of the coolant I don't know enough to calculate if the reduced fluid velocity would provide enough additional heat dissipation to compensate for the reduction in half of the heat transfer surface area so I just went with what made sense.
The original setup which is now sitting on a shelf in my workshop combined had the same frontal area as the stock C5 radiator with the addition of ally tanks/not plastic and being 3 row not the stock 2 row.
The new radiators have almost 50% more frontal area and are a lot further away from the wheels which should eliminate air packing and wheel debris issues.
Please by all means if you think that there is a better way or a different way let me know as I am currently working on version 2 and really don’t want there to be a third version.

[Desertrunner]

Hi Dave,
Up front I will say I have no experiance with the GTM but I have done a lot of work on cooling other type of systems. The major failing in cooling systems is caviation to the water pump. You would have seen suction pipes to water pumps with wire in them to stop the hose collapsing. That is a bad sign becasue it shows that the water pump if pushed will capaviate.
If it was my car I would tee in the hot to the top of both radiators and tee the outlets together. Every radiator has some friction and results in a pressure loss, it maybe only 5 psi but when you send it from one radiator to the next the loss maybe only 10psi but as pressure calcs are logarithmic to move the pressure from 5 psi to 10 you need 4 times the energy.
Don't want to get to complex unless you want me to. The surface area is the surface the direction of flow of coolant doesn't change that.
Last point the installation will be a lot neater.

If you want me to expand any points please ask I am happy to help in any way.

Tony

[Fraser D]

Tony,

I hope to have everything mocked up over the weekend and will post some more photos

[mendo]

I just saw a Lambo this week, it has both radiators mounted behind the rear wheels. there is ducting that starts right behind the door windows and the radiators vent straigh out the back. ???? maybe?

[Desertrunner]

Test Fan Computer Type.JPGHi Dave,
Had a though this idea might help you develop the project. When I run tests I use a computer cooling fan (couple of buck worth) with long leads and attach a multimeter attached to the end. Need to check its the type of fan that when spun generates power. Set metter at 0 to 24v DC. Zip tie it were ever you want to read the air seed. You will be surprised what you learn from this simple test.

RadiatorTest using computer fan.jpg

[mendo]

Good Idea Runner!

[Fraser D]

That is a good tool to have.
Thanks for posting.

[Fraser D]

Rev 2 Mounting completed. I have to break out the TIG to finish up the radiators then plumb them in. Still finalizing the fans and AC condensers.
I like these way better. A lot more work but......
There is a heap more photos in my photo bucket link below.

[Fraser D]

Radiators plumbed up and leak tested OK.
I used the material from the original set of radiators but later on I will replace the tubing assembly with single piece mandrel bent items.
Fans on order and I will enclose everything with aluminum sheet once I am happy that everything is running Ok.
AC condenser will be mounted in a novel place with photos to follow once I sort it all out.
I should have the hood mounting completed this Sunday.

[OZIGTM]

Great work Dave, it's looking really good.

Rohan GTM# 285

[Fraser D]

Great work Dave, it's looking really good.

Rohan GTM# 285

Thanks, where have you been? DOT Engineers haven't pissed you off have they?

[chronies5]

Extra-Rigid Type 304 Stainless Steel Woven Wire Cloth, 1/4" Opening Size, .063" Diameter, 24" X 48" Sheet

There is still lots of work to do with securing the tubing and bracing and detailing the mounting frame. .


Mcmaster is charging an arm and a leg for this stainless steel wire cloth material - if you are not into wasting money check out some more sources, like the following:

www.grainger.com

http://www.bwire.com/index.html

They will beat the pricing and shipping costs of mcmaster. hands down.

[OZIGTM]

Thanks, where have you been? DOT Engineers haven't pissed you off have they?

Hey Dave,
I'm still going, as you know with projects like this life gets in the way; the balance of keeping everybody happy.
Engineers are OK if you follow the rules, there is really only two main issues; beam / torrsional test and emissions test plus every state has different rules.
One more GTM arrived last week into OZ, which is good more the better I think that makes 7.
Cheers,

Rohan

[Fraser D]

Extra-Rigid Type 304 Stainless Steel Woven Wire Cloth, 1/4" Opening Size, .063" Diameter, 24" X 48" Sheet

There is still lots of work to do with securing the tubing and bracing and detailing the mounting frame. .


Mcmaster is charging an arm and a leg for this stainless steel wire cloth material - if you are not into wasting money check out some more sources, like the following:

www.grainger.com

http://www.bwire.com/index.html

They will beat the pricing and shipping costs of mcmaster. hands down.

At the time I purchased mine there was about $5 difference between the two vendors and I had an order to place with McMaster anyway.
You are correct in that you really need to shop around because prices can vary greatly.

[Fraser D]

I was able to get a couple of things completed today with the biggest milestone being getting the hood brackets progressed and the hood mounted.
The hood opens and closes like a champ!
The hood brackets still need to be powder coated and the base plates glassed into the hood.
The tube work has been cleaned up ad painted so it is time to start putting things together for the last time and finish off the aluminum close out panels.