Nuke VX build thread

[Triathlete]

I think the problem (at least for me) was I was going on your pictures in which the fans were sitting on the radiator. That is why I was agreeing with chadzu.

[VXorado]

FF dynamics agrees with PK.

FF Dynamics sell their electric fan conversions with a smaller shroud. When I asked about the shroud being 2" short on each side of the radiator, this was the reply I received.

Hi Jon,

You received the correct size for your radiator, we do not build custom shroud kits that cover the entire radiator core, we only cover enough of the radiator for maximum fan efficiency and maximum cooling. If the shroud was to cover the entire radiator, air flow from normal driving would be obstructed and the vehicle would overheat on the highway. By leaving enough of the radiator exposed around the shroud there will be no high pressure areas and air will freely blow through the radiator without obstruction at speeds faster than 30 MPH. But rest assured, this system has been tried and tested over the years and it will cool your vehicle without any problems what so ever. All of our fan systems are built for maximum efficiency across the board, from cooling, to gas mileage to performance.


Any other questions, just let us know.


Thanks!
FFD

[PK]

FF dynamics agrees with PK.

FF Dynamics sell their electric fan conversions with a smaller shroud. When I asked about the shroud being 2" short on each side of the radiator, this was the reply I received.

Thank you VXorado.
I never wanted this to become a p*ssing contest, just some friendly advice.
I have no problems at all with the fans being behind the radiator, and having a shroud. In fact, a shroud is a must.
It is the amount of radiator that you are blanking off that will have no effect on how the fans work, but will seriously restrict the amount of air flow through your radiator at highway speeds.

Whatever you end up doing, I hope it works for you.
If you end up in Moab next year, I hope we can shake hands and have a beer as we look at your rig.

PK

[sleveritt]

Well, different companies having different techniques I guess because my diesel shroud is enclosed all the way around (diesel mechanical fan though) and on a GM SUV, as well. Trust me, these are on-highway vehicles only. I was going on what I saw in my garage and what I read for OFF-ROADING:

Four Wheeler Magazine - "Keeping Your Cool: Cooling System Tech"
The fan shroud should cover as much of the radiator as possible. Don’t be afraid to trim the fan shroud slightly to clear the water inlet or outlet. Do make sure that the shroud seals against the radiator all the way around. It’s ideal to have the fan motor mounted 1 to 2 inches away from the radiator, although some tight situations call for a low profile fan setup like the one shown here.




Then Griffin radiators (King of the Hammers sponsor) has this from the Cooling Bible



As you can see, no gaps whatsoever, but these are off-roading designs. And really, when you look at my rig what is the first thing that pops to mind? How many highway miles does it drive or how much fun it is to off-road that thing? This is our third vehicle and only intended as "inclimate weather use" and off-road. I got a diesel and car hauler for extended trips. (Nothing made me sweat more than driving the Trooper 1200 miles to Moab, then off-roading it for several days while hoping I didn't break some unique expensive Isuzu part that would prevent me from driving the entire family back home and getting back to my job.)

Also, I've not got the steering monster figured out yet. Still have a constant drift the the right requiring constant turning to the left - even while driving a straight road. Adjusted the aluminum bumpstops to prevent the tires from rubbing the sway bar and track bars. Kept the axle on stands, kept tires off, ran the engine and it didn't move after 15 minutes of idling. Alignment is good on all three axis and squareness. I'll have to keep testing (same thing after driving several miles, maybe street tires, maybe new upgraded PS pump)...

Sam

[Scott Larson]

Man, some people sure do get testy with a little friendly critiquing! After looking closely at all pictures offered, I would be a little concerned too about not only the percentage of the radiator that your fans cover but also the angle of your shroud face in regards to directing air to the fans. The picture of the Griffin radiator shows fans that cover 75% of the rad surface with a stand-off shroud. The pics of your rad shows fans that look to cover considerably less area and appear to be flat mounted to the rad core. Now, I realize that you have rectified that assumption earlier, but the images do tell a different story. If you are new to the whole custom build thing, it is hard to get used to people second-guessing your every decision, but get used to it; even the pros get second guessed by their peers...Don't take it personally. I wish you the very best of luck with your build and hope you can sort out all the details to your satisfaction and don't stop posting!! (Even if you do take some heat for your decisions.)

[sleveritt]

...shroud face in regards to directing air to the fans. The picture of the Griffin radiator shows fans that cover 75% of the rad surface with a stand-off shroud.

The math generally works out that ~70% of square radiators can be covered with a round fan, but only ~50-60% can be covered on rectangular radiators. The Griffin picture shows a standard fan/shroud. The Four Wheeler pics are of a "slim line" or low profile fan/shroud. Unfortunately less efficient, but necessary because of the lack of room under the hood. I need to order a vent connector for the upper coolant hose to connect the steam vents from the LS engine and "burp" the system since the hose is higher than the radiator cap. Just a little trapped air just kills the efficiency of the system. Even with all these things the 13 y/o composite/aluminum radiator meant for a aluminum V6 still may not be up the cooling demands of a iron block V8. Only time will tell.

Discussions are fine, but when some says "stick to your guns" - what they are saying is you are wrong. Well, prove it on your end because I have proof on mine. But I'm not above learning from others.

Sam

[Scott Larson]

Good on ya Sam, well said! I do truly believe PK was trying to help though. You have alot of interested people here...

[89Vette]

PK, you really need to rethink your logic. You have two contradicting statements - "But by far the greatest amount of cooling is needed when you are travelling at highway speeds (NOT TRUE AT ALL), uphills (TRUE)etc, when you have the gas pedal to the floor.
At these times the fans do little, or no work at all. The air flow through the entire radiator frontal surface caused by your forward motion is enough to cool the engine (THIS PART IS TRUE)."

Why wouldn't you think the engine is doing a lot of work -- especially with a mega-high-profile jacked truck rolling down the road at hwy speeds? That work creates heat -- and needs cooling?

(Obviously air flow isn't hard to get at speed, but that wasn't the point when PK made the comment.)

Cool project, btw. Lots of know-how went into it for sure.

[sleveritt]

Attaining highway speeds is the greatest amount of work for the engine, by and large, once at that speed maintaining it is much less work. Just works the instant MPG on any newer vehicle for confirmation. Once at highway speeds, most vehicles have adequate passive cooling. Now on the VX, there is not a lot of surface area for that kind of airflow. I've contemplated cutting some air vents on the front fascia, but that would be towards the end of my checklist.

[Scott Larson]

Yeah, the grill on the VX could be a real limiting factor when it comes to air flow through the radiator. You could remove the OEM driving lights and open up those holes, then fab some ducting to route additional air to the rad. Just a thought... It may be tough to retain the original look of the front end.

[sleveritt]

After a couple of wheeling events last year, the overheating continued. I had a radiator shop take a look. They said everything looked fine on the outside, but maybe the radiator was getting clogged over the many years of use/abuse. Ordered a new direct replacement radiator & cap a couple of weeks ago. Here was the thing, even though the old radiator had been drained of coolant and transmission fluid, it was still 4 pounds heavier than the new one. Installed last week. After the burping process for the LS engine, everything appears to have been fixed. Just finished wheeling this past weekend at Superlift ORV in Hot Springs, AR with the Arkansas Crawlers (brother is a member) - never had a problem, even when towing a Jeep Cherokee up a mountain trail. That made me exceptionally happy! Now to concentrate on the road wander...

[eternal21]

That made me exceptionally happy! Now to concentrate on the road wander...

Worked wonders for me, but you're a *bit* different, so I dunno if the same thing would work out for you, too.

http://vehicross.info/forums/showthread.php?t=25219

[sleveritt]

Thanks for the suggestion. That is my backup plan if I can find a worn joint/bushing somewhere. Don't want to cover the problem with a band-aid if I can find the root cause. I also want to upgrade the rear track bars to something beefier/adjustable (perhaps some "flexing" is occurring while on the road?). I did a complete hydraulic flush and did find some "water", maybe 10-15mls in 2 quarts. Any amount could have lent itself to creating an emulsion. Oh well, every correction helps.

[sleveritt]

And check out the latest wheeling pics from last weekend at Superlift in Hot Springs, AR

http://www.vehicross.info/forums/showthread.php?t=25341

[Frankenstein]

I dug up your build thread after looking at your wheeling thread. I love your rig! How high to the bottom of your rockers? If I go bigger than 33s I don't want to cut all that metal out you did. I think you have about the same lift as mine. So maybe 35s for me down the road.