Double Coolers

[Martin Blair]

Hi, would it be possible to stack to oil coolers ontop of each other, put a new stock unit under the one on the 400 and splice them together somehow to double colling capacity? thanks.

[cabex]

I'm sure it would be possible. But I have never heard of anyone doing it. You just do it and tell use how it works:D

[TRX_Thumper]

four stroke tech makes a nice additional oil cooler that cools the cam an rockers

[400exdad]

I've read some posts on this and I remember someone being concerned with the pressure drop the oil would have going thru the two coolers. It may starve the motor of oil. JMHO

[Martin Blair]

well that could be true, but what does fst run there head collor, if you will, off of? do they have a seprate pump?

[Matt Fisher]

Look at your side cover, where the oil filter bolts are. At about the 10:00 mark, you'll see a ridge, that's the cam's oil galley. You can follow it right up the side of the cylinder. The FST cooler simply taps in at the side case, and returns the oil at the cam, just like Honda does it, but with cooler oil. No chance of starving the motor of oil.

I would try to avoid standing the bike on end for extended periods of time, this would drain the cooler. Upon startup, there would be minimal oil on the cam until the pump moved enough oil through the lines and cooler to make it to the cam.

[optikid123]

a couple guys have done the 2 stock on top of each other trick they said it worked great or u could get the fst one which is even better i think

[RytM1]

Due to moving, I haven't been able to hook up with the shop that works on my sportbike. I am thinking about replacing the stock EX cooler, with one from a sportbike. The shop has a bunch lying aroud, so I just have to find one that fits.

[300exazzkikr]

you could always get a bigger oiler cooler like one from an automatic transmission and hook it up this way more oil will be cooled at once.

[bmw500hp]

Originally posted by HN400exracer
Hi, would it be possible to stack to oil coolers ontop of each other, put a new stock unit under the one on the 400 and splice them together somehow to double colling capacity? thanks.

I think there is a builder that employs double coolers...If memory serves correct , it's King Rage in Texas (DEE) it's also said he builds one **** of a 416.

[oregonrider89]

I was just wondering why you needed two coolers? What kind of riding are you doing?

oregonrider89

[RIDER11X]

Originally posted by 400exdad
I've read some posts on this and I remember someone being concerned with the pressure drop the oil would have going thru the two coolers. It may starve the motor of oil. JMHO Doesn't the oil pass through the cooler then drop to the dry sump tank? If so wouldn't the pump always have the tank of oil to pull it's supply from?:confused:

[nakomis0]

Originally posted by RIDER11X
Doesn't the oil pass through the cooler then drop to the dry sump tank? If so wouldn't the pump always have the tank of oil to pull it's supply from?:confused:

It does go from the cooler and then into the tank.

1. So can you mount the 2 coolers, and then tap into the same place FST does? (So it throws the oil on the cam)

2. Does anyone have a diagram of the FST system, mainly where it taps into?

3. Also what about the oil pressure is there enought to run 2 oil coolers?

I got an extra cooler I might try this. If we think it can work.

[nakomis0]

Originally posted by nakomis0


3. Also what about the oil pressure is there enought to run 2 oil coolers?



I guess if you kept the extra cooler lower than the other cooler, than gravity would help?

[TRX_Thumper]

mickey dunlap at FST knows what he's doin..he wouldnt make the kit if there wasnt enough oil pressure.....

[oregonrider89]

The FST kit is designed for one cooler, not two. Thats something to think about.

oregonrider89

[Matt Fisher]

Originally posted by nakomis0
It does go from the cooler and then into the tank.

1. So can you mount the 2 coolers, and then tap into the same place FST does? (So it throws the oil on the cam)

2. Does anyone have a diagram of the FST system, mainly where it taps into?

3. Also what about the oil pressure is there enought to run 2 oil coolers?

I got an extra cooler I might try this. If we think it can work.


I used the FST design when building my oil cooler. I used a 5"x10" cooler, mounted to the front downtubes.

Pull your clutch cover off, you'll see the lines cast into the cover and center case. It taps in on the clutch cover, but you need to be precise. Plug up the line that goes into the center case/up the cylinder. Output is directly into the cam cover, easy.

There seems to be plenty of pressure to run both coolers. The lines that feed the cam are quite small (a smidge bigger than a BB), so the oil reaching the cam has been in the cooler for some time; it's thoroughly cooled off. I used a Radio Shack infared temp sensor to check efficiency, over a 50 degree drop. It drops the temp enough to touch the cooler with your bare hand.

There are pictures of my friend's bike (same setup) on the Yahoo! Groups TRX400EX list, see the photo's section. If someone knows how to copy from there and post it here, feel free.

[TRX_Thumper]

back when fst site was up i clearly member it sayin this is not a replacement its simply an additional oil cooler and u will still use the stock one also....

[Martin Blair]

Maybe i will have to pic up another cooler and try it, i will ahve to convence my dad to let me first, since he is still paying for it and im sure it would void the warrenty, but its only anothe stock unit im goign to mount under the current one with some short hoses to hopfully provide twice the colling.

[Matt Fisher]

Why are you concerned with additional cooling? Given the mild nature of your current mods, I'd just run some 15-50 Mobil 1 in there and spend your time/money elsewhere.

When (or if) you start making significantly more power than stock, then you'll be creating significantly more heat than stock. Don't screw with the warranty, imo.

[Martin Blair]

Originally posted by Matt Fisher
Why are you concerned with additional cooling? Given the mild nature of your current mods, I'd just run some 15-50 Mobil 1 in there and spend your time/money elsewhere.

When (or if) you start making significantly more power than stock, then you'll be creating significantly more heat than stock. Don't screw with the warranty, imo.

Good Point, I think i will wait till i start having big heat problems.

[nakomis0]

Heres that pic Matt was talking about.

That looks like a HUGE cooler. Any idea what that cooler is made for?

Anyways it looks like you wouldn't have much of a problem mounting 2 stock coolers.

[nakomis0]

Heres the other side...

You can clearly see the fitting that taps in near the cam.

I can't really see what that lower hose is going to.

[UglyMotha™]

fst just uses you typical automotive oil cooler it wouldn't be very hard to pick one up at most part stores

[Matt Fisher]

The cooler came off a Mitsubishi Starion Turbo.

If you look at the picture, there's a small bracket welded between the frame rails; the cooler bolts to that and the upper shock tower.

Routing of hoses:
Both hoses go up above the top of the cooler, this way they stay full of oil even when the bike is not running.

Input hose comes out of the case right behind the clutch cable bracket (see the brass fitting), goes over the top of the top of the cooler, and into the left side of the cooler.

Output hose comes out of the cooler's right side, over the OEM cooler, and into the cam cover's brass fitting.

You can see the 2 white zip-ties I used on the input hose, those have been replaced by 2 OEM brackets. Maybe when I get back from my honeymoon I'll try to take some pictures of them.

[400exdad]

Okay, so I didn't know what I was talking about. :) Actually I thought I was recalling what Mickey had said in one of his posts or Q and A's. Of course, he could have been protecting a source of income. Which is okay to do since he has to stand behind his products and does do the tests. However, even if the cooler dumps straight into the tank, the extra resistance of the oil passing thru the extra cooler will increase the pressure at the pump, or in other words, decrease the volume of oil the pump is able to pump.

I remember Mickey saying that he hated folks buying his kit, seeing how he placed it in the system and then returned the kit, building their own. If I was going to try to install an extra cooler, I would do it like the earlier post recommended. The Mickey Dunlap way. Its tested and works.

Just went back and looked that pic. Matt did his right. I like the cooler with the protected fins. I do have one question though, where you tapped the incoming at, is that before or after the filter?