2 pass heater core mod help

I have a 2 pass D-tek Heater core, the one that comes in the flowmaster XT kit. Basically, it's a chevette core. Now it's currently a two pass core, like all stock chevette's. What I'm wondering is what i have to do inorder to mod this core to work as a single pass rad.

BTW, through some googling I found out that 2 pass cores have 16x the resistance of single pass cores!

Basicly you have to put a outlet into the bottom tank and join the top 2 tanks together (the hard bit).

What you could try to do is just put a outlet in the bottom and use a Y splitter so you can have the original top 2 barbs as inlets. athough i dont relly think that will work aswell.

Idealy the in/out barbs should be on opposing corners of the core so that water flows across in an eaven distrabution.

Edit: I allways though single pass cores would have 4 times less resistance than dual pass. You would half it because the water only has to pass through each vein once and then half it again as you would effectivly have 2 times the amound of veins. Its probably not that simple tho.

Ok, I'll use a Y on the top 2 barbs (I already have a spare Y) and I'll put the bottom barb on the side so it lines up with my pump intake. Hopefully this will increase my performance and It will also take a point where my tubing kinks out of the loop

Send some pics, this is really interesting. How are you going abour putting those barbs in? braising, epoxy(JB weld?)

getting me thinking....

You could also use your RBX/White Watter as the Y, by running each outlet to it's own rad inlet....

I'd use a large fitting on the bottom, to keep flow restriction to a minimum. Running two 5/8" inlets into a single 5/8" outlet would slow things up a bit if you were to use the above method.

You can simply drill a hole, and flush from the top with water afterwards, to keep the drill chips from entering the passages.
Drill the hole smaller than needed by 1/8" then use the jaws of needle nose pliers to "dimple" the hole inward to the correct size needed...this makes for a much stronger solder joint than just soldering to the edge of the tank's hole, and is how a heatercores origional tubes are mounted (though they use spiffier tools).

The flow restriction difference isn't just a matter of halves, many heatercores have an odd number of passages, like mine is 9 in, and 8 out. But I'll leave the strange math to others

Diggrr said:

The flow restriction difference isn't just a matter of halves, many heatercores have an odd number of passages, like mine is 9 in, and 8 out. But I'll leave the strange math to others

Click to expand...

Yeh didnt think of that.

Would have to work out a fraction or something

bahh maths!

Diggrr said:

You could also use your RBX/White Watter as the Y, by running each outlet to it's own rad inlet....

I'd use a large fitting on the bottom, to keep flow restriction to a minimum. Running two 5/8" inlets into a single 5/8" outlet would slow things up a bit if you were to use the above method.

You can simply drill a hole, and flush from the top with water afterwards, to keep the drill chips from entering the passages.
Drill the hole smaller than needed by 1/8" then use the jaws of needle nose pliers to "dimple" the hole inward to the correct size needed...this makes for a much stronger solder joint than just soldering to the edge of the tank's hole, and is how a heatercores origional tubes are mounted (though they use spiffier tools).

The flow restriction difference isn't just a matter of halves, many heatercores have an odd number of passages, like mine is 9 in, and 8 out. But I'll leave the strange math to others

Click to expand...

Yeah, I guess I will use my WW as the Y, it would work rather well.

I'll use 5/8" ID barbs for the outlet, and drill out my pumps input barb. That should help flow resistance a bit.

It's threads like this that really make you mad when you just installed a heater core...

Now I'm thinking about yanking it out and making it a single pass. Maybe a future project though.

Cheers!

Well Mr. Reaper, you could always do THIS.
That's the rad I'm using now.

For a full sized one, I'd go with 5-6 layers of glass though.

reaper79 said:

It's threads like this that really make you mad when you just installed a heater core...

Now I'm thinking about yanking it out and making it a single pass. Maybe a future project though.

Cheers!

Click to expand...

hey man, the only reason I'm going to do this is that I'm going to be buying a GPU block and replacing the hoses on my system, so I figured I'd do this while it was down

start with a single pass heater core?

For instance, an "Find The Perfect Heatercore" on overclockers.com shows the heatercore for a Mercury Comet : W/O AC: 1977-71 (7+3/4 x 6+1/8 x 2) with 5/8" inlet/outlet on top/bottom.
So if you can deal with a radiator about 1 3/4" taller than what you're now using, you don't have to so any soldering at all.
I'm sure there are lots of other single pass heater cores - I just don't know what they are. The guy behind the counter at the auto parts store probably does, though...