# Rear mounted radiator



## EL DRIFTO (Jul 11, 2004)

stole a pic from this thread http://forums.vwvortex.com/showthre...radiator-anyone&highlight=Rear+mount+Radiator










i also borrowed this idea from here : http://www.yotatech.com/f163/rear-mount-radiator-s-149178/


"I have a 79 toy with a heavily built 4.3 in it and we run in the mud all day long and the way i was told to go is to put a small radiator up front and then put your big radiator in the bed, using your heater core hose's to supply your big radiator in the bed."

my scirocco has some serious heat soak issues on boost & it way affects my spark knock limit/power
i've considered the ve of the engine, comp map, comp, timing, fuel, thermostat, coolant flow directions
& it should be able to stay wot without pulling any timing

having a mostly centrifugal sc history, with vag knock sensor, i've played with various octanes & got a feel for octane needs vs compression & engine temp, although my boosted 16v project is more of an art project now, in preparation, i've got the na16v running strong on 87 octane, no cooling fan @ all, oe radiator. I've done this on all my na applications & can sit in the drive through & traffic for 10 minutes on a 100F day, evidently convetion will cool a naked radiator 

so pulling timing & lowering comp doesn't win races & heatsoak kills high compression knock limit to the point of no addition of top speed or a sustainable top speed, wot

so i've decided to add an additional oe radiator, attached to the underside of the spare tire well. 
i've measured & all i need is two inches above the bottom of the rear suspension beam for clearance & it's there...i might put a jack under the spare well to get a little more, but i have no intention of cutting anything out of the car

i was also gonna plumb it in "pexx", a cheap plastic pipe used in homes, powered by the two lines that would normally go to the trans cooler, no fan back there.

any input ??


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## crashnburn987 (May 11, 2004)

So you want to put an additional radiator under the car?

Wouldn't it be over exposed to road debris and other things that can poke a hole in it? I also wonder how effectively air flows under the car...l.enough to keep the radiator happy?

Interesting idea though.


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## woody16v (Sep 21, 2009)

not under, behind. though im having a hard time figuring out where exactly you would be putting it. you shouldnt really even need a very big rad though with all the tubing. and you'd have to have a pretty huge wing to hide it in if you're planning to do like that ur quatro


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## EL DRIFTO (Jul 11, 2004)

well the scir front end is smaller than a rabbit, smaller than anyone here
& it doesn't get out of the warm up section @ the very bottom of the temp guage, unless i sit for 10 minutes, with the 72C right now, no fan NA

but then i block it with a FMIC & it's downhill from there, fan or not
not to mention the IC @ a stoplight, next to the hot radiator

had a work caravan i pulled out the ac & fan, it cooled fine, stock thermostat
i could sit with the heater on for hours during the winter, no fan

anyway, got the idea, old porsche used just a set of lines that ran to the front of the car, into the wheel well & back, then they'd put an "oil cooler" in the wheel well if they needed extra help

convection does allot, especially considering what the heater core fan does alone to temps

anyway, looks like the project is coming along & i'll be trying my 4:20 oil cooler idea first
(where i tapped the cold side of the water pump to cool the oil, not heat it)

i'm hoping it'll help since it was perpetually heat soaking the oil, now my IC will heat soak the radiator instead

then i'll try using just a heater core in the rear first, instead of a huge radiator


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## huichox4 (Nov 8, 2004)

I have a heat problem in my R32 turbo therefore decided to take the front mount intercooler and move to an air to water intercooler, the difference is that instead of using the air to water intercooler radiator in front (which would have been the same as my air to air intercooler blocking air flow to the engine rad) I made a hole and ducts in the back of the car, check it out here, 

http://forums.vwvortex.com/showthre...er-intercooler-syatem-users-I-have-a-question

I am still building it, it will have fans and everything to force air through it when standing still and or while moving depending on air flow.


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## EL DRIFTO (Jul 11, 2004)

well i scrapped the bad oil cooler idea & went straight for the proper additional rear radiator...

i don't have any pics yet, i'll get some, but it works so good without a fan, i'll be removing the front radiator entirely

now i can fit my 500hp fmic in the scirocco just fine 

people that have put the battery in the rear of the 2000 lb cars can imagine what moving the radiator back there TOO handles like, the front of the car is actually hungry for 45 lbs of crap :what: :lowrider song:


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## GTijoejoe (Oct 6, 2001)

You can also try to increase the fluid capacity of the system to help :thumbup: 
Also you can add fans to anywhere you can't get direct airflow (if they fit)


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## EL DRIFTO (Jul 11, 2004)

well after taking the front one out, i need it after all :laugh:

i thought i had completely shut off the front radiator with a pinched hose, but apparently i only slowed it down

so after putting it back in & running the car with both, there's way more cooling potential, reserve & volume

right now it's running off the auto trans cooler lines, so it circulates even during warm up, i think i may tap the return into the front return, so it's all thermostat controlled, here's a pic of the front one gone when i had it running into the stat



















i could fit a fan underneath & still be above rear beam height, although i wont










i'll get more pics, but the final setup has the rear lines terminating high near the battery location to keep it primed, without air getting into the lines during connections

since the front one is thermostat controlled, the rear one alone brings the water temps down into the warm up region on the guage

i have to use the shorter rabbit radiator for my snail, y dont i just get a turbo ??










now i guess i put the IC on the front park bench

there's nothing like a mk1 with a 10 x 6" core support right in the middle of everything that cant even hold up the radiator :banghead:


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## EL DRIFTO (Jul 11, 2004)

well it's a done deal
the final location of the rear in/out lines is the 16v trans cooler location, basically the heater core in/outs

got the car running boosted yesterday & played with it on the highway, it only has 5 gears...

anyway after getting back home the self contained SC was ~90F
front radiator ~80F
the fmic was ice cold & so was the charger pipe to the TB
the intake manifold was 70F & rising from the engine heat, i just shut it off

so in closing, i can't get the temps over the warm up region on the guage & wot continuously 

like autobahn, driving to work or road racers that are wot, full G or full braking the whole time

so in review that's 12lbs out of the nose, (no fan) & ~20lbs all to the rear, bolted a radiator to the floor pan, now heatsoak is impossible 

so a total success for me

now if i could just build my own boost a pump...

3/4" black plastic pipe was ~$30 for 100'
two sherlock holmes heater core pipes to reduce & turn 90 degrees, they're new
note the lack of fan






















here are the two adjustable valves i added to reduce volume to the front radiator & more to the rear












here's the one on the oil heater, i think it cools fine, but reduced flow should only reduce the speed it picks up heat, on brief wot












i like function over appearance, maybe unpopular, i like this pic











ignore the rrr, i couldn't get it's base pressure up high enough, it's going


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