I am considering installing the radiator in the rear area of my Fiat. I would like to see some examples on how others may have made it work for them. I would also like to know if there are any positve or negative things to consider running it in the back. Thanks, Bob
If your building a drag car it works great,even better with small HP motors. I seen it done bad mostly,and even tryed it and put it back up front,got cooling back and some trunk space,but front didn't look as show car. For street driving it just a bad idea. #1 Air flow in rear is always poor,#2 rad needs to be much bigger if it's even got a shot to work . #4 Drit is bad with air shoops and #5 screens fill up,#6 12volt fans big enough to do any real good will suck bat down fast,#7 water flow in most all of the set ups have big air/steam pocket points in high spots and humps that hert cooling a lot #8 and brupping the water need doing more then most with say. I've herd a few that have a rear rad say it's working for them,when there just to proud to say they should of put it up front to start with. Even laying down up front can be better then in rear,but has it's own games that need playing with #4 ,#8 Have fun,if it drag only or trailor Qween fine, forget all I said.
I think flyin brian is running a rear mount radiator in his roadster. You may ask him. I ran one in the bed of a jail bar pickup once because there was no room in front of the blower drive for a radiator. Scoops in the sides of the bed and a shroud ran to the front of the radiator. Big electric fan and a jockey pump at the radiator. Put a second fill point at engine up as high as we could get it. Never took a long trip 30 or 40 miles max but it didn't over heat. Most trips were about 7 miles to the track and home again.
I ran a custom 4 core in the rear of a plastic 27 with water running through the frame rails. Three 12" fans and a louvered (a lot) deck lid. Worked well and is still on the road. Warm 355 w/ 5 speed
Im also planning on this rear setup,you got to be able to do it with out problems if the baja racers do it in the desert right? also can anyone with experience show some pics .
Yup, I am. It's actually a secondary radiator, plumbed in series with the aluminum '65 Mustang style up front, and it works great. The rump-rump 472 Cad runs 190 on all but the hottest days of summer in traffic, and even then never over 215. No auxillary water pump, the stock pump, 185 degree 'stat, 3 electric fans, one up front on two on the rear, and I'm Smil'nBrian! Brian
Alot of good points and advice. I am planning to run a electric water pump with the setup which I forgot to mention. Still would like to see some pic's of some idea's on how others have made it work. With the Fiat space is at a bare minimum. I've been scratching my head for a while trying to figure out were to put everything.
I think flyinbrian has probably been running a rear radiator longer than anyone, but the idea seemed to re-emerge with the "Littleman coupe build" thread. Since Littlemans build there have been more than one that has gone that route, for different reasons I guess, but in my case, it was for the look. There are a few really well done rear radiator coupes on this site that can be found via the search function. I would not include my coupe in that list as I certainly don't have the skills those guys have. My coupe is not completely done yet, but so far runs really cool. I am running two electric water pumps. Littleman is the expert and in my opinion the one that kinda started the recent rear radiator phenomona. I have to say its probably not considered to be "traditional" by most but your Fiat seems like the perfect candidate. As I said, Littleman is the expert, but I will be glad to provide any info I can about plumbing, pumps, fans, radiator etc. with respect to my car. PM me if I can help. Brad Outlaw 31 Coupe
Bob, at the recent Good Guys Show here in San Diego, a Studebaker was exhibited with a Potvin blower on the motor leaving no room for the radiator. The builder/owner had relocated the radiator to the trunk and behind the rear window were two matching quick release caps --- one for fuel and one for water... he had a goose neck mount raising from the package tray at the rear window pointing towards the driver and it held the temp gauge. Pretty neat set up.. I have a couple of photos of it but have no luck posting them...
I'm running a large (Chevy dually crew) radiator under the bed, behind the cab of the COE with dual 17" shrouded electric fans. 160 stat and stock pump on 502/502 horse bbc. 1 1/2" copper back and forth with the cap and filler at the manifold like a sprint car. Okay so here's what I've found. I have plenty of cooling capacity. The engine temp will actually come down when stuck in traffic at an idle to the point that both fans shut off (175 degrees). The problems are that the system will not thermosyphen with the engine off which results in the fans cooling the radiator but since the temp switch is in the intake, the fans never shut off and will (and have) drained the battery. Allowing the truck to idle untill the fans shut off stops this but is not always convenient. The other problem is with air flow at speed and diminished cooling. At 65 mph the temp will rise to 200-210 on a Michigan summer day (80% humidity 85 degrees). While it drops quickly when you slow down to 35-40 I know I am fighting an air flow/vaccuum under the bed (the rad lays down nearly flat and has alot of airspace around, above and below). I guess I can say the system works although with its eccentricities. During the construction of the truck I knew I wouldn't have enough room up front under the very short hood of the COE for a radiator large enough to do the job hence the choice to try this method. I plan over the winter to add another radiator and fan up front (where it should really be) tied into the system I already have in place. While it will be on the small side, I think it will help make the system much more efficient. Engine to front rad to rear rad back to engine. I don't know if this helps anyone, but its my experience. Chuck
Those are super giant rads mount high to clear rocks and crap,not the same as a street driver at all,not a very good compare there if ya think about..
Chuck, I would think you would go engine to rear, rear to front, front rad. to engine. The water will be the coolest from front rad to engine. JMO
brigrat, I was thinking (generally what causes most of my problems!) that I might get some more of a thermosyphen if I went to the front first as it will be the highest point of the system. Right now the highest point is the thermostat housing and then a turn down and to the back. It will be easy to change the flow though by just moving some hoses around. I expect the front radiator to help keep the temps down at speed and anything else would be a bonus. Chuck
I run a rear mounted radiator as I have zero room for a front mounted radiator. I live in Lousiana where summer temps can be brutal, 100+ and 100% humidity. My radiator is a 4 core aluminum job made for a 69ish Bronco. I run one 2800 CFM fan. Radiator is vertical with no tilt angle. My firewall has sublte cut outs that allow air to pass through and into my trasmission tunnel which is also special. Tunnel is wedge shaped to grab air and force it to the rear. Radiator is surrounded by "wings" which force air into the radiator. Bed cover is louvered to allow hot air to escape. Coolant is transfered via 6061 aluminum tubes which add to the cooling effect. I am currently running the stock water pump and have had zero issues so far. During the summer with a 170 degree thermostat and the fan running I never get above 180 degrees. Having said that, I have not yet driven it much and have yet to get stuck in traffic. Not sure what it will do, just my .02 worth
I'm in the process of moving my radiator to the bed of my truck right now. The plan is to make room for intercooler that will fit in the grille shell. I'm going to run 2 radiators that end up being about 2-1/2 times the area of the front one. I'm hoping that the extra area will make up for the decreased airflow. My radiators are going to have to lay flat because lack of space. I'm going to try it with just fans at first. If that isn't enough air I'll build some vents or scoops. I'm working on the tubing now. I used 1-5/8 x .095 mild steel tubing from the firewall to behind the cab. From the firewall forward to the water pump and the water neck I'm using 18 Gauge mandrel bent stainless. Also I'm going to run 2 caps, one on the motor (the highest point) and one in the back. I figure it will help with the filling and bleeding of the system.
Brian Thanks for checkin' in. I thought you were doing that with success. Hey hows the old truck commin' I haven't seen a progress report on it?
Several points in this thread need clarification. Chuck needs to run his relay low-side thru the ignition switch so that the fan does not stay on. Your truck's airflow would change direction radically at speed, prolly going forward cos of air swirling around and under the truck bed, thats why racecars have side skirts. This hot air would be sucked back thru the rad by the fans. Don't move the rad Chuck just make sure the hot air is ducted rearward. Pull-type fans work better than pushers. ALWAYS use a shroud to pull air from all corners of the core. Seal the rad with a firewall type panel to separate the low pressure cool air side from the high pressure hot side otherwise in stop-go traffic, the hot air goes forward to the low pressure zone which circulates the hot back thru the rad. Thats why modern cars (since 80's) run a seal from the core support to the top of the grill. No need to run more than one water pump. Davies Craig (Australia) has an extremely compact LIGHT WEIGHT 12v pump with multiple porting options in the kit. Have run one on a cross-flow SBC installation for 4 years, zero probs. Had a radiator shop solder a flange direct on the header tank bottom corner and mounted the pump there (make sure u use the outlet, or cool, side header tank AT THE BOTTOM so that low coolant level will not cavitate the pump). Google for their midwest distributor. Bob's Fiat gasser should be the best/easiest installation if it's standing up against the back panel/doors with louvres. Mat Thrasher, how do u remove the lower of 2 radiator caps without draining the system??? Also the lower cap will puke coolant every drive cycle and empty the system in a week or 2. One rad cap at the highest point is all thats needed. Use small bleeders from a rad shop or McMaster Carr at high points in the system to burp or bleed airlocks @ $2.08 each, search them for 'brass stop cocks'. Best tubing is 6061 x 063 aluminum with beads at both ends. 304 at .049" mandrel bent stainless exhaust tube also great cos u can do it at home. Jim
Mat Thrasher, how do u remove the lower of 2 radiator caps without draining the system??? Also the lower cap will puke coolant every drive cycle and empty the system in a week or 2. One rad cap at the highest point is all thats needed. Use small bleeders from a rad shop or McMaster Carr at high points in the system to burp or bleed airlocks @ $2.08 each, search them for 'brass stop cocks'. Best tubing is 6061 x 063 aluminum with beads at both ends. 304 at .049" mandrel bent stainless exhaust tube also great cos u can do it at home. Jim[/QUOTE] I planned on just using the lower cap just help to fill the system. My thinking is that because both the motor and the radiators will be higher the the tubing connecting them, it will be hard to get the system filled. I'll fill the lower one until it's full then put the cap on. Then I'll go to the front and fill that one. That way the whole system is full and easier for the pump to start pushing coolant through the system. For the front I was just going to use a 1" NPT plug and use a standard radiator cap in the back. The reason being I'm real tight for space on the front of my motor. I didn't think having the radiator cap at a lower point would be a problem. My thinking is that it's only going to pop off under pressure then close. I didn't think gravity would matter but maybe I'm not thinking of something. Let me know what you think. I really don't want to try squeeze a radiator cap and overflow tank in the front but I will if I have to.
Mat, the cap has to be at the highest point cos it overflows every time you start the engine. You should of course be using a coolant recovery system cos this will bleed the air out every time and refill with liquid. I assume the tags rad is the highest point. To fill the first time, crack the t'stat cover 1/8" till all the system is full. OR as suggested, drill and tap the t'stat housing for 1/8 bsp tapered thread stop cock. If the rad is highest, buy an inline water neck/cap from Summit and use it as close a possible to the t'stat and at least as high, air will eventually get puked to the catch tank. NOTE TO Everybody....you should crack the t'stat every time u fill a new system to bleed air cos the air trapped in the motor will not conduct head to the t'stat and cause it to open, so the motor will boil over first time..........messy right there! Note that 'goose_em' is using ONE regular size rad with no probs.
http://www.tunersports.com/davies-craig-electric-water-pump-8040_p4909.html several listings on Google "shopping". Davies Craig is http://www.daviescraig.com.au/ for tech info
Good thread. Since I drove my car, in traffic, for the first time yesterday, I've discovered I do have some overheating issues. It can sit in the driveway and idle all day and not exceed 160 degrees. It never overheated to the point of an eruption when driving, but its only 65 degrees outside, but it was running right up to 195/200 degrees. Removing the trunk lid, which is louvered, helped considerably, but not enough to run on the 100 degree days we get down here. I'm going to try a different fan as my Summit "puller" is only 2200 CFM. I've heard that the Lincoln Mark 8 or Crown Vic PI engines had something like a 4000CFM fan. Part of my problem is that heat can not get out through the louvers. I will try and seperate the cool and hot side of my radiator with panels as suggested. BOutlaw
Here are a few threads. http://www.jalopyjournal.com/forum/showthread.php?t=514955&highlight=rear+mounted+radiator http://www.jalopyjournal.com/forum/showthread.php?t=426663&highlight=rear+mounted+radiator http://www.jalopyjournal.com/forum/showthread.php?t=408088&highlight=rear+mounted+radiator http://www.jalopyjournal.com/forum/showthread.php?t=300770&highlight=rear+mounted+radiator http://www.jalopyjournal.com/forum/showthread.php?t=280731&highlight=rear+mounted+radiator http://www.jalopyjournal.com/forum/showthread.php?t=233968&highlight=rear+mounted+radiator http://www.jalopyjournal.com/forum/showthread.php?t=182077&highlight=rear+mounted+radiator That was off the first page of that search there 41 hits and several good ones on page two if you want to look further. Cheers
Elpolacko had a good post or two on CFM advertised and real world, try a search or PM him for advice.
Chuck, Instead of vacume, you probably have a high pressure problem under the bed, the air can't get OUT. I had the same thing initially with the roadster, there was no place for the air to escape. I hill-billy'd that by cutting three 3" dia. holes in the rear wheel wells, out of sight behind the tires, and problem solved. The holes are just barely above the level of the radiator. The fans couldn't push against the air pressure building between the floor and the radiator core. With the holes cut, air has a place to escape at speed, and viola, highway run-hot problem solved. Parked in the driveway with the fans running, you can really feel the air moving behind the tires. It was simple fix for what I thought was going to be a big problem. I may put some vents in the floor behind the seats for early spring or late season rides, as the car doesn't have a heater. Brian
Brian, After reading this and every other thread on the subject this weekend I think I will try moving the fans to the opposite side of the radiator as an experiment. I may have a situation where the fans are fighting the natural flow of air under the bed at speed. I have a lot of room under there but never considered that the airflow at speed might actually flow opposite of the travel of the vehicle. This will be very simple to change and check the results. If I still feel I have a problem I have found another radiator which, while smaller than the monster I am running, will fit (tightly) up front in behind the grille where it belongs in the airflow. Tied in with the current system it will give me approximatly 40% more capacity in the system and be smack dab up front. I have considered an electric pump, or even booster pump, but don't trust (I know a lot of you fellas disagree) an electric on a street driven vehichle. Also, theory says that as it is a closed system, the stock pump will move the volume of fluid it was designed to irregardless of distance. At any rate I still believe my problem to be airflow and not capacity and have some changes/experiments in mind. Heck its not like we'll be driving them alot around here for about 4 months anyway! Chuck
BTW........the Davies Craig controller is expensive. You don't really need it. Run the pump all the time with ignition on. Your engine t'stat and fan t'stat will do their thing. If u wanna warm up faster, use a momentary off (spring loaded) switch to CUT the pump at the first few traffic lights in the morning. Chuck, I ran electric pump for 35,000 miles over 4 years before I left Australia. The car is in storage there. Old brush-type heater fans run for 30 years, these are printed circuit motors with no brushes and no wearing parts. Jim
Thanks TMAN for the additional links. I did a quick search but didn't come up with those. All of this is good information. Still on the fence about the rear radiator but I am also, like some others considering running one up front and one in the rear. Thanks everyone.
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