Which Duel Oil Cooler Configuration?

[FlyingW]

OK guys, I bought an oil cooler and lines off EBay to add a second cooler on my 350X but I want your opinion on which way to plumb it. Series or parallel. Take a look at the picture and give me your opinion. I would also like to know what you base your decision on. Your feedback will help me make a decision.

[Rex Karz]

As to dual coolers:
I would go series config. The parallel route would be hard to equalize flow, and woud be only be beneficial if one cooler couldn't handle the volume of flow. The series route insures that both coolers would be used completely and would eliminate the use of tees. IMHO

[Honda250sx1986]

I agree.

[NOS_350X]

I ran mine in series. I just thought that the oil pump can only push so much through and in parallel it woudnt get anymore cooled that before, where in series it would get the oil cooler because its being ran through twice.

[Dan10]

Why do you need dual oil coolers? The benefits are going to be minimal as far as cooling is concerned (I have extensive experience with this topic in regards to Harleys). The main benefit comes from the added volume of oil. Still, if you were to add an oil temp gauge I would place an estimate of less than a 10 degree fahrenheit drop in oil temp. A better method to cool the oil would be to add a thermostatically controlled fan to the current cooler, and better direct air flow to it. I do not have any data to prove this for a 350X, but I would assume that it would be very similar to a HD.

And as Rex stated, series is the way to go if you are going to use a second cooler.

Just to add further confusion to the subject, a single larger cooler is more efficient than two separate coolers.

[realbadlarry]

Yeah, you got to think about restriction of flow with the multiple coolers. You get to the point where you are actually hurting your cooling capacity because the pump was only designed to push oil thru 1 cooler. I would go for a single larger cooler and a fan.

[NOS_350X]

Dan you couldnt be more rong. I dotn know the temp diffrences but my engine went from running exremely hot the (the whole engine) to with the secondary oil cooler i can touch any part of my engine after riding for long periods of time. Also i didnt use the 350x cooler as my secondary one. After adding the secondary cooler it was a night and day diffrence between the two.

[tndn92]

2 oil coolers are a must if you do alot of motor work i run mine in series my motor runs a lot cooler it was running really really hot i run a fourstroke tech secondary oil cooler

[FlyingW]

What a great bunch of replies. I love to spark heated discussions over things other than freakin politics. Anyway, let me share my thoughts. Unless we can get ahold of the original Honda engineering specifications on the development of the 350X cooling system then we will have to draw our own conclusions.

First of all, the oil pump is a tried and true design. That same pump design has adorned many models with variations in the impeller size based on oil demand.

Second, the oil pump is designed to circulate the oil throughout the engine as well as pushing it up and through oil cooler and back down. Without putting a pressure gage on the oil system I'd say that the pressure is somewhere in the neighborhood of 15lbs. Just a guess. Now lets say I did add a second cooler down low on the frame in parallel. Now the oil pump has to work harder to circulate the oil fighting gravity as well as sending an equal amount of oil to each cooler. This probably would wear the pump out sooner than normal. The cooler that has less restrictions will receive more oil. Restrictions can be defined as adding a lenght in the tubing or additional coolers. To minimize the "load" on the oil pump it would be best to keep the restrictions in the oil system down to a minimum. With that said, is my conclusion that when adding a second cooler in series would provide an overall increase in heat dispersion. The critical factor here is that the second cooler be kept at the same lateral plane as the first. That way the movement of the oil from the first cooler to the second be as unrestricted as possible. The extra oil added to the system to accomodate a second cooler would also contribute to a more efficient cooling system. The trick here is to add only enough oil to fill the second cooler. To measure this, remove the original cooler and tubes and fill the cooler and one of the tubes with oil. Do the same with the patch tube between the two coolers. This total amount is what would need to be added to the crankcase. Now dump the oil in to a measuring cup. The patch tube between the the two coolers is obviously shorter than the supply tube on the first cooler so keep that in mind.

Putting too much oil in the crankcase can blow seals an accurate amount is essential

There were some questions concerning the benefit of adding a second cooler. The oil system is designed to keep the motor oiled and cooled within a certian temp range. I can tell you that here in Oklahoma in mid summer, my engine gets pretty hot and as we all know from engines principals 101, excess heat can destroy a motor. Adding a second cooler on any liquid cooled engine is only a benefit as long as the demand doesn't exceed the capabilities of the pump.

The addition of a cooling fan on the 350X isn't practical as we all know the 350X has a stator only, no battery to share the electrical load, well that is unless your'e running a Goke.

Well, that is my 2 cents.

[NOS_350X]

Is what i did was put the normal amount of oil, run the engine for about 30 seconds to a minute to get the lines filled, then re check it. Running it for that period wont heat up the oil enough to expand.

[tndn92]

thats what i did the first time too i ran mine for a few seconds and kept adding until it was full now i know how much to put in my second cooler in mounted on the frame rail where my battery used to be i have had no trouble at all with it and that is where fourstroke tech recomened me to mount it the cooler they sell does not need air to disapate heat

[dreadhed]

Also i didnt use the 350x cooler as my secondary one. After adding the secondary cooler it was a night and day diffrence between the two.
What did you use? A tranny cooler?

[250sx]

NOS_350X can you post some pics of your setup? would love to see it.