LS6427

iTrader: (2)

Since Im going Iron block with twin turbos.......ive been thinking:

Since there's so much room in front of the engine that a single turbo can fit in between the radiator fan shroud and the water pump bell housing and crankshaft pulley......

How about putting two radiators slapped together, ran in series, so the hot coolant coming out of the block/heads goes into the front radiator first like normal, the coolant sits there and gets cooled by ram air and fan suction......then the MUCH cooler coolant that is in the radiator behind the front radiator goes into the block/heads the next time the tstat opens up. Then that hot coolant in the front radiator goes into the back radiator to keep cooling as the new hot coolant goes into the front radiator. And so on......

The hot coolant would have A LOT more time to cool way down before going back into the engine. It would have "sit" time in two radiators instead of one. Maybe couple this with a tstat that has a certain sized hole drilled in it so warm/hot coolant is also being circulated so the block/heads do not get a blast of coolant that is too cool.
THAT WOULD TAKE SOME TESTING OF COURSE TO FIND THE SWEET SPOT.

Or maybe a half sized custom built radiator as the second radiator sitting behind the main radiator.

SO.....what do all think....? Should I keep drinking or could this work....?

EDIT*****sheet metal ducting behind the front radiator directing the hot air down to the street is the idea.....so NONE of that hot air goes into the rear second radiator. Post #8

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allout06

iTrader: (11)

hmmm, i would think a larger radiator with more surface area would cool the coolant just as efficiently if not better. imo... i see what your saying though.

turbocamaro125

iTrader: (3)

prolly need a higher flowing pump to push the coolant thru 2 rads

SPRAYED 01

iTrader: (22)

I guess the main question is what issue are you trying to fix? could that work? Sure, but why?

LS6427

iTrader: (2)

None issue yet. But when my TT kit goes on my 390 iron block, I will not be happy if its gonna run 220-230*F all the time like some people report. I'll make something that'll work. A shop here said they can make a custom radiator any size or shape.

But if it runs cool after the CBR TT goes on....then I won't do anything. But I'm thinking down here in south Florida, it's gonna get hot in city driving with the a/c blasting.

I'm sure a second radiator right behind the main radiator, but just half the size....will be pretty awesome. I plan on using the Miezeir electric pump, should provide plenty of flow for an additional half-size radiator.

My 427ci never got above about 205*F......180-190*F cruising on the highway......that's what I want with this one.
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djfury05

iTrader: (30)

I would have a custom rad made somewhat like KILLER-LS1 had made. Griffin, Ron Davis, BeCool etc all good choices. Might as well make it dual pass if your gonna do a custom one as well to keep the rad lines simple and on the same side. Try your best to use 2 puller fans WITH a shroud!! Keep the air dam underneath the radiator and you should be fine. Maybe use some water wetter but I doubt you'd need it.

js2fst

iTrader: (12)

Hopefully be cools have gotten better they use to crack all the time but I have only had three

LS6427

iTrader: (2)

Yeah, I'll definitely keep the factory shroud. Been thinking about it and measuring things.
The thought was to keep the fan on the front radiator attached normally. Then behind the fan shroud use thin sheet metal to direct the hot air from the fans straight downward to the street. Then the second radiator sits behind it so air can enter the front of it and then have 1 or 2 puller fans on it as well.

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OUTLAWZ RACING

iTrader: (9)

I seen somthing similar to what the op is looking at. While in Germany there was a ls1 swap 944 porsh at a car show in nurnburg. While talking to the owner he said he ran dual radiators because of the high speed runs on the bahn. They where small and rad 1 was hook up to the top of rad 2 and rad 2 bottom outlet to the water pump. I dont know the thickness but they where small. He said during the high speed runsthe car never seen 220 even at 6,800 rmps for extend romps. and thats with a stock thermostat. I dunno if it would the weight would out weigh the cooling. Unless the radaitor was small.

2000RATA

I don't think you will need it. There is no reason the car will run hot. No hotter than the 427 did. A cheap and easy little bit of extra cooling capacity is to run the LT1 radiator. It's $120 from a parts store new.

ta02zx10r

iTrader: (19)

talk to some of the engineers and tech guys at afco or griffin etc. They do this for a living and can fix you up with a radiator to suit the situation. The problem you'll run into is the fact that if you can't get good airflow through those radiators (which you are doubling the thickness) if will not cool. It will probably be worse than better because it'll cease the airflow and just sit there and "clam bake". There are alot of variables that people don't take into consideration when designing a coolant system. Air flow, shrouding, distances between shrouds and the radiator to allow the fans to be effective along with proper fan orientation and type (whenever idealy possible). Double pass radiators have both the inlet and outlet on the same side. They have a "block" or partition in between the inlet and outlets which divides the core in half so it goes in the inlet and travels the length of the core and then turns a 180 and heads back down the length of the core to the outlet. Talk to Jay at afco. Very resourceful guy and has done ALOT of cooling systems. Anyways, that is my humble 10 cents. I'm by no means an expert, but I have spent a great deal of time on the phone with Jay learning about all of this. So not trying to be a know it all just trying to help.

LS6427

iTrader: (2)

Yea, I've had the LT1 rad in my car with my 427ci for like 8 years....ran cooler than the LS1 a little bit. Very good mod.

I'll see what happens with the CBR TT kit.....if all is good and temps are 220 or less in city driving......I'll leave it alone. If not, I'll do a dual radiator. It has to make things run cooler.

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91sonomast

Let's say you hypothetically were going to go with the original plan. Wouldn't you want the radiator that was going to return coolant to the engine to be in the front? In the original proposed setup the hot air coming off of the front radiator is going to warm up the rear radiator and I believe wouldn't make for a much cooler engine. By switching them around your cooler coolant would go into the front radiator getting the coolest air and cooling it even more.
Just a thought.

pwrtrip75

iTrader: (8)

You dont want it to run too cool... thats why they have thermostats, to keep them from running too cool.

LS6427

iTrader: (2)

From my post #8.......

Yeah, I'll definitely keep the factory shroud. Been thinking about it and measuring things.
The thought was to keep the fan on the front radiator attached normally. Then behind the fan shroud use thin sheet metal to direct the hot air from the fans straight downward to the street. Then the second radiator sits behind it so air can enter the front of it and then have 1 or 2 puller fans on it as well.



But the water/coolant that's immediately entering the front radiator will be amazingly hot...210-230*F. Even after it sits there for a few minutes with fans running and ram air cooling it......after it then cools down, then flows into the rear radiator.....ain't no way it's gonna get hotter again. It will continue to cool a little bit more.

But with my above idea, none of that hot air from the front radiator will touch it.....and the puller fans on the rear radiator will be further cooling the coolant.
A hole will need to be drilled in the tstat to keep a certain amount of warm/hot coolant to always flow into the heads/block so things don't get too cool. Don't want the temps going up and down all the time....gotta have it stay somewhat steady......

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KILLER-LS1

iTrader: (18)

having two radiators behind eachother would not be very efficient. It would be better to go with a larger core custom setup. The airflow through a rad is very important. air coming out of the first one would be very hot, and moving a lot slower. putting that air into the second rad wouldnt do much besides complicate things.

I made a shroud for my entire front opening. there is a shroud that forces air into the intercooler, then another shroud that forces that air (along with more air scooped from the air dam) up to the radiator. I noticed a big change by doing that.

Also, i believe that the guys running hot are using too small of a radiator. I just called griffin, told them about the "universal" one that everyone on here uses, and told them to make that work for 1000+ hp and LS1 compatible. They made the core thicker, and added a steam port for the heads, and a bung for the coolant level sensor, They said that the universal one wasnt designed to handle that much heat.

i also have 2 10" spal pusher fans. I have never overheated, and my car runs 180 all day long even in 100 degree weather. ive been on the dyno in 108 degree weather for 5-6 hours at a time with just a small blower fan and the radiator and IC have worked great.

tonypaul

iTrader: (2)

I have twin Griffin radiators in my Lambo Diablo replica. One on each side in the rear of the car with one electrical water pump on the engine (sbc) and another electrical in line water pump between the radiators.

The water pumps come on with the key and the twin fans come on at 160 degrees. The car never gets over 170 degrees during the hottest Texas summer days. I drilled 4 small holes in the thermostate for circulation due to the electric waterpumps. I recently had to change to a thermostate with only 1 little hole drilled in because the car would not get warm enough to turn on the fans in cooler weather.

So the twin radiators work really good if you have a way to set them up in such a way like in my situation.

LS6427

iTrader: (2)

Post #8...... A shroud behind the front radiator to direct the hot air straight down is what I'm thinking......

Well see, it might run cool with my LT1 radiator........

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kpeterson

It’s been a long time since I had studied Heat Transfer and Thermodynamics but going from memory:

There are three things (some covered above) that jump out as inefficient with the use of heat exchangers in series.

The rate at which heat transfers from one fluid to another decreases as the temperatures get closer to being the same. By reducing the coolant temperature in the first radiator you will diminish the effectiveness of the second in a series set up.

In series the water’s rate of flow through the radiator is twice what it would be by running the two heat exchangers in parallel. Slowing the flow down through the heat exchangers gives more time to transfer the heat out. The water pump should also have an easier time pushing the water in the parallel arrangement.

By placing one heat exchanger in front of the other two undesirable things happen. The airflow through both will be reduced. And, the effectiveness of the rear heat exchanger is also reduced because the air it sees has been heated by the first. I have heard some interesting debates about not much being gained by four vs. three row radiators because of both of these issues. I understand the idea of ducting the heated air down from the first to avoid heating the second radiator but the issue of providing adequate incoming air to the second radiator comes up as well as adding restriction to the air exiting the first. The sharp downward turn will likely significantly reduce airflow and the same thing happens trying to get fresh air into the second radiator. The distance between the two would have to be pretty large in order to not reduce the flows to either . It is likely that in this set up the out going air is restricted for the first radiator and the incomming air is restricted to the second.

Basically the most efficient use of a heat exchanger is the largest area and thinnest core that will provide adequate temperature reductions.

I’m not saying that what is proposed would not work but I believe it an inefficient use of the second radiator. Of course this is based on what I remember from classes taken a long time ago.

chuntington101

Google rear mounted radiators. Done to death the other side of the pond (england and EU) on many race cars (postly 4pot turbo engines). if you can fit a large enough rear rad you might not need the front as the rear rad would be seeing much 'better' air (NOT having had to go through a intercooler).

You WILL need fans on the back of the rear rad to get the airflow.

Dont just stick one core behind the other. The ambient air has enough trouble getting through as it is!

Alteratively keep the stock rad where it is, run a A2W setup and remote mount the HE towards the rear of the car.

Chris.