5VZ-FE 3.4L Fan and Bracket Delete / Electric Conversion

Hello everyone, a first post here, and a relatively new to me Tacoma, but I have been in the automotive world for quite some time. I have owned and modified classic minis, classic bmws (I've spent a lot of time in the BMW 2002 world) and a number of other bikes and cars over the years. Before you guys flame me and tell me to do a search (I have), let me explain.

I intend to do an electric fan conversion when I do my timing belts, and will do a proper write up at that time. The question I have, is why hasn't anyone removed the fan bracket entirely, replacing it with a cover to keep the timing belts protected? Shorter accessory belts and one less spinning pulley equate to less frictional losses (hence, more power and better efficiency). I see one stud that may interfere with the alternator belt, but that will be easy enough to work around.

I'm after better mpg, shorter warm up times, better low speed cooling, better air conditioner performance in traffic, water crossing benefits, and if I free up a pony or two in the process I won't complain. Don't try and talk me out of it, I've made my mind up and I won't entertain that discussion here. I'm a mechanical engineer and the benefits of a (properly implemented) electric fan far outweigh the downsides in this application- If someone wants an in depth explanation as to why, I'd be happy to explain.

I'll post more information about my truck as well as start a build thread shortly. Lots of very trick stuff in the works for this taco.

 

Welcome to TW, I’m interested to see what you have in store for this project. I have yet to see an electric fan conversion that was as efficient at cooling the 5VZ as the stock fan, especially in hot conditions, but that certainly doesn’t mean that one doesn’t exist.

If you do entirely delete the engine-driven fan assembly, there should be no reason you can’t get rid of the fan bracket. Just have to source the correct belt lengths to replace them with.

 

Thank you drr! I need to take some measurements, but upon an initial search the dual fan setup out of a C6 corvette (or Cadillac CTSV/ many other LS1 powered cars) should do the trick when paired with an intelligent controller. I'm in socal, so I have plenty of hot weather to contend with. My day job is designing environmental test chambers, so I know a thing or two about moving heat. Outside of work I have a love for machining and fabrication, so plenty of resources at my disposal to do things as well as (if not exceeding) the OEM.

I suppose nobody ever removed the fan bracket so that they wouldn't have to source different belts?

 

You need to also make sure it has a proper shroud to direct airflow

 

Oh absolutely; If the shroud from the donor vehicle doesn't fit correctly I intend to make a new one that is well sealed.

 

I did this three different ways and never got really good results. I did a custom shroud with two fans, the stock fan with a large aftermarket fan, and the stock shroud with a Taurus fan. I had a smart controller on them all. I got a little better low end acceleration (it was a tiny change) and no change in MPG. Every setup caused overheating problems when I was towing uphill. I still have all the stuff if you'd like to buy it.

 

What controller are you using? I would be happy to look over whatever equipment you have and consider making an offer if its what I'm after.

Overheating while towing surprises me; unless if it was at low speeds, the fan shouldn't have an impact on cooling performance once you are up to speed. Are you sure the fans were blowing in the correct direction? If the stock cooling system wasn't sufficient on the highway, a larger fan won't really help. If you could provide a description of conditions that caused the overheating (and whether it would cool back down once load is decreased) and performance compared to stock fan.... all would be useful information.

Thanks!

 

So when folks claim power savings from eliminating the clutched mechanical fans, I understand there is some savings during periods the fan would be engaged.

How much is that offset by the extra alternator effort needed to spin up the electric fans?

I'm not sure the full on value for a normal Tacoma owner............

 

There is a very long thread about this elsewhere on the website that got so confrontational it had to be shut down. I'd rather not start it again, but some people think it works. I agree but I couldn't quite get it to work as reliably as I wanted.
And yes, it overheated uphill at low speed while towing. Not hot enough to cause damage, but I lost some coolant.

 

Theoretically, the mechanical fan will require less energy to spin than the electric fan. The reason for this is the losses associated with converting the mechanical energy into electrical energy that is stored in the battery, and then the subsequent losses associated with converting the store energy back into mechanical. The benefits come from the fact that the fan does not need to spin most of the time, aside from at low speeds when airflow (from the vehicle moving) is not sufficient. Additionally, shorter warm up times mean a shorter rich running period. Additional benefits include the ability to cool the engine after the engine is shut down and having higher air flow when stopped in traffic to improve air conditioner performance and engine cooling. I don't intend for this to become controversial; if you want to keep your mechanical fan, by all means, do so. No system is perfect and there are positives and negatives to both systems.

I record my fuel mileage so I will be able to provide real world empirical data to show if there is any MPG improvement. I'm not going to spend money on dyno time, so I won't discuss or try to claim a power increase. Even if I don't gain much MPG I will be happy to have the faster warm up period and improved AC and cooling performance. IMHO the shortcomings in previous electric conversions come down to inappropriately sized cooling fans and in some cases poor ducting and/or wiring. What works for one person in one climate may be wholly insufficient to another person in another climate. The stock fan moves a LOT of air; I don't have a CFM figure but most aftermarket fans won't displace enough. Important to note the towing package uses a different fan to provide additional cooling.

 

That's a good summary of why it works and I'd love to hear back on your results. I'll post the stuff I have left from my attempt in the For Sale section and I'll mention it here when I do.

 

Just my experience but I had dual electric fans on my truck when I bought it (previous owner had them installed) and they were terrible at keeping the motor cool, had issues with overheating especially in 4wd (slow, meticulous climbs). Had a shop install a stock fan clutch and it's worked beautifully ever since. It might have just been something wrong with my particular e-fan setup...if you were able to come up with an e-fan solution that works really well I'd be interested in seeing it for sure.

 

I'll definitely keep you all posted. Part of the issue is people generally go with the cheapest fans available when they do this swap. More often than not the rated CFM of the fans is far less than the actual output, especially in the case of cheap knockoffs.

 

Mine were Flex-a-Lite, not sure about the quality but it looked like a decent setup. I almost wonder though if mine was an install-error with the wiring, or maybe they were just old and needed servicing.

 

Flex-a-Lite makes a fairly decent product, but depending on the CFM of the unit it may just not have been able to keep up. Another very common install error is having the direction reversed. They will work fine at a dead stop, or if you're driving in reverse, but at slow speeds the air entering through the grill is pushing against the air being forced forward by the cooling fan which creates a stagnation area in the radiator- ie no flow. Not necessarily what was wrong with your setup, but I've seen it a number of times. An old unit can also be problematic... a worn motor will require more amperage, generating more heat and possibly less than maximum air handling.

At some point I'll try and determine the cooling requirements of the engine (and add a factor of safety/ increase the requirement for a turbo/supercharger build) and report my findings. Cooling system design is fairly complicated; for example, you may be able to get away with less airflow if you have a larger heat sink (a larger radiator), or vice-versa. To give a rough ballpark, off the cusp number, assuming the stock 5vz-fe makes 190hp (142kW) of power, if it is 20% efficient, that puts the heat output at approximately 710kW stock, at full power. That is a lot of heat to move, but luckily for us, you will hardly ever use full power at low speeds for more than a brief period, so the cooling fan only needs to deal with a small percentage of the total load. There are numerous factors to consider; ambient temperatures being a very large part of it. Hopefully this sheds some light on why it is difficult (and discouraging) to simply swap on an off the shelf cooling fan and to hope it will provide sufficient cooling. There are multiple ways to skin this cat.

In summary: Many many MANY factors, people run into issues because of incorrect information provided by forums and vendors, electricity is complicated, installation errors reduce effectiveness... etc etc etc. I'll do my best to make things simple and to report the shortcomings of the system as well as the steps I take to mitigate those shortcomings.

 

The juice may not be worth the squeeze. But more power to you if you enjoy tinkering. Good luck!

 

It totally might not be, I couldn't agree more. I do love to tinker, though. Only time will tell.

 

Thanks for doing this, wish I had the time but priorities. Please document well.

 

I wish I had enough room on my truck for a mechanical fan. I would start the truck feel how much air is being drawn through the grill, I bet that once you swap your electric fans in, you will be disappointed in the results.


I'll offer you this, "If it ain't broke, don't fix it".

 

I've said it here before, I have been running dual electric fans for about 17 yrs and have not had any issues with them. I seem to be the exception. I live in the desert southwest where
we have already hit 100 earlier this week.

@Rocan I think you will be fine.