Modifying a koyo n-flow for a vmount
 

I am about to build a custom v-mount setup, and was wanting to know what all needs to be done to relocate the outlet to the top. Can you buy an endtank somewhere or will it have to be fabricated. Also modifying it in this way would make it a dual pass, because it has to go to the bottom tank and then back up right? A n-flow is already a dual pass, so would there be any complications in using it? Would it make it a quad pass? Also I know most of the sprint cars already use a radiator that has the inlet/outlet both at the top. Does anyone know where to get one that would fit a fd?

Is this for a street car? Be careful with how many "passes" your radiator has. Of course the advantage is that your coolant has more time inside the radiator to cool down, but the disadvantage is that with every "pass" that you add in a radiator, the effective pressure of your cooling system rises by A LOT. This puts extra load on your water pump. Should be fine for cars that are at a decent RPM most of the time, but for street cars that experience traffic, traffic lights, etc., probably not the best.

So I was right and it would make it a quad pass? The longer the coolant stays in the radiator the less coolant gets cooled....that would be the only reason I could see it being bad. It is for a Sunday driver, it might see a little track time.

Koyo N flow radiators are actually triple pass radiators to begin with, hence the name "N Flow" because the flow follows the shape of an "N". So, yeah, by bringing the outlet back up to the top by modifying the endtanks would make it a quad pass radiator. IMO, triple pass is already too much.
I think you made a typo, the longer the coolant stays in the radiator the MORE it gets cooled. The downside is the additional pressure.

RX7store already sells modified Koyo radiators for custom v-mount systems, is that what you're looking for?

I'm actually about to dive into a custom v-mount myself, but I haven't found the perfect radiator yet. I'm leaning towards a custom single-pass dual core crossflow radiator, but there's still the issue of routing the outlet to the top because crossflow radiators always have the inlet and outlet diagnol from each other (i.e. inlet - top of left endtank, outlet - bottom of right endtank).

Inevitably, it seems that custom/modified endtanks are a necessity for a good v-mount.

It wasn't I typo, I was just saying the coolant in the radiator gets cooled more than normal, but stays in the radiator longer, which would cause less coolant to pass through the radiator in the same amount of time, which would probably cause a loss in total coolant performance. Like I was saying about the sprint cars though... They already have the both inlets in the top.. So I wander if there's a racing radiator with both inlets at the top that would be big enough to go in a rotary.

Sounds like you and I are in the same boat. In the past couple of weeks, I have looked at so many radiators and various designs. Griffin, Ron Davis, Afco, Be Cool, Fluidyne, etc..... the list goes on. One thing you might consider, Ron Davis will build a radiator however you want it. They have a custom order sheet and you fill in all the custom specs you want. I believe Afco will do the same thing, but I haven't found a custom order sheet for Afco. I was going to call them today but was too busy at work.

Here's some pictures I found yesterday of a single pass crossflow radiator modified for v-mount. http://www.fd3stech.com/gallery2/v/album_001/album/

There is a huge multi page thread that I posted in that has a lot of pics of how the radiator is modified. Search for it. I posted in it also.

The rad in the above pic probably won't work. The N flow probably won't work either due to the mods involved in relocating in/outlets. Sell it and use the funds toward modifying a regular Koyo or getting one custom made.

Myself and others on here already went through the rounds with all the custom radiator people mentioned above. Some of them are a pita to deal with but it is doable. You will wind up with a cross flow rad rather than the usual top-bottom flow rads used in the FD. Afco was the easiest to deal with. So was Alumrad.com

Regular Koyo works fine. Dont worry about it.

Check out my thread,https://www.rx7club.com/3rd-generation-specific-1993-2002-16/ebay-radiator-sin-818605/ received a lot of flak but it runs great and cost half the price of many others. Let me know if you are interested i can fab some up, for cheap. I will be making some basic v mount kits with all the ducting soon for a very competitive price. Check out the finish product it turned out very good.

This is just a thought, but for the v-mount, on my setup, I'm putting the intercooler on the bottom, and just slightly modifying the radiator brackets to move it up about two inches and slightly change the angle. Might sound backasswards to pretty much everyone but to me it makes more sense. The radiator is on top away from the ground and no modifications have to be made to it. putting an adjustable splitter between two would allow the amount of air between the two to be"tuned". Also i have a koyo too, I love it.

On the Koyo / PWR style radiators , modifying the tanks is easier than most think. Simply take the outlets on each end and swap them. This will position everything in the right direction and allow you to run a Mazda B2300 Upper hose for your mazda with a little trimming. The lower hose I ran a hardline too..

i'll post pics of my radiator if I remember. Works excellent and retains the N flow design keeping the car fairly streetable. People worry that the lower will be too low, which is silly unless your Vmount sits unreasonably low and has no guard. I made a aluminum guard to keep it all well protected in the event a speedbump is a little taller than estimated.

i am making mine out of a greddy intercooler and meziere radiator

Its been done already.

It is backasswards IMO. :)

Did it already, Leave it the way it sets stock. Just buy a flex hose for the upper it works better this way. If you flip the spout it won't fit due to the proximity. You can see my V-mount in my profile pix.

I thought about that and like the idea, except you have to run more intercooler piping...which would mean less efficient and more bends so it will have more lag. One of the main ideas of a v-mount is to have shortest intercooler piping you can get to reduce lag. When you get it going though tell us how it works.

i thought about leaving my rad up top, for the only simple principle of another member idea, if i crash or bottom out my intercooler, i can limp home, if i trash my radiator... yea.. ain't happeneing, BUT i'd hate to lose my very quick boost response, so i'm assuming that it's best to use our stock style radiator b/c it's up and down, and converting to a v-mount would just make it into a dual pass, down, over to the other side, and up. correct? how big should the "lower pass over" end tank be? i imagine it has to be able to flow all the water from one side to the other as quickly as possible... so i assume should need to be fairly big? (sorry for the rant)


Clos

I highly doubt that it will have a noticably less lag, i couldnt tell. I think efficeincy is the name of the game with a v mount and also Keeping your intake temps, as well as coolent temps down.

If you think about it, there should be the same amount of preasure because flowing with long or short piping. It just might take longer to preasurize the system. I dont think there is going to be any preasure drop from a front mount either. its kind of like a garden hose with water in it, does the water go any faster if its a short hose, no it just takes longer to get to the end of the hose. Dont know if you are following me but it makes sense.

I'm not master of fluid dynamics or anything, but I do know that bends will decrease response time. So the farther you move the intercooler away the more bends there is going to be. And actually you do loose water pressure from a 5 foot piece of hose compared to 600-700 feet, not much though.

Does anyone know who makes custom radiators reasonable?

I flipped the spouts and had absolutely no fitment issues and used an off the shelf mazda radiator hose.

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I believe the Knight Sports V-mount radiator starts off with a Koyo N-flow radiator. You can see the welds in the endtanks where the separation is. It seems they keep it as a triple pass radiator, but they move the inlet from the bottom end tank to the top by running a hard pipe along one side of the radiator.

And thats how we did mine as well. Very easy, doens't require removal of the tank, just rotation of the inlets

I'm not a master of fluid dynamics, but I do know more piping will cause a loss in response time. Also if your piping has to go farther.. the more bends it will have which is a large factor in lag. As for the water hose thing, I redo swimming pools and the length of hose has a large factor in draining or filling a pool, More so when draining because the pressure and volume of water is alot greater. So Theatrically The more boost you run the greater effect more piping and/or more bends will have on your system.

Well any way you look at it, its not going to have a night and day feeling between the two. Do both and tell me you can feel the difference..... V mounts are the best no matter what though

Top shot of mine, probably why mine doesn't fit the spout. Size matter's an also this v-mount is for a single turbo GT35R not for the twins. My Rad also sits further into the body so I don't destroy my car over bumps. I don't use ducting due to the size of both rad an IC they catch almost all of it. The only flaw was I cut my stock rad braces off in order to fit the largest IC possible an the koyo. The performance flaw is it takes song long to fill, However my temps for both water and IC are absolutely ridiculous. I'm still reading stock water temp gauge but it has dropped almost a 4th from reading a bit over half way.

https://www.rx7club.com/picture.php?...ictureid=11045