Quick quesiton (sort of on topic) Will making a shroud for the electric fan that diverts the air to the side and out the wheel well or another area be beneficial than it being spread around the engine bay? Would this help keep temperatures down or would it not be that noticable?

WOW, just wow....

Dude, a mechanic is not the same as an electromechanic; so PLEASE stop trying to impress us with your mechanic degree and your AAP job...

Then let's see what I daid before you chime in with your VAST knowledge:

So you are trying to prove a point to something that I already stated BEFORE you walked in?

Should I say thank you :rlaugh: or smack you :pat:


Full load at 2000 rpms?

I thought we already concluded that LOAD was applied through electrical draw, and NOT by rpms?!? :lol2:

NEVER said batteries are not part of a car electrical system; just that WE are not taking them into consideration for this debate.

Well isn't that something, maybe you haven't read our own rules on this forum. :sadwavey:

The battery is just as important as the alternator. It's clear from your posts in this thread that your electrical knowledge is very weak, yet you continue to argue with people who obviously know much more about it than you do. Your snide comments and multiple emoticons are just making you look a bit silly. Please just stop posting. Read and learn instead. And don't get all pissy about it either...

I totally agree, and I've said that countless times.

If you just did it for looks then say so. I've never said it didn't look better. That's not what I was talking about, so what's your point?

We are talking about the load on the alternator, and how it becomes HARDER to spin while the amps demand gets higher. At least thats what Aaron and myself where discussing; so in that aspect, we don't need to involve the battery. Sorry if you, or want be electro mechanics don't agree...

On any case, I truely belive that the efan robs power myth has been busted; like it or not.

I must have miss understood you then. I didn't like working around the shround and I like that fact that I don't ever have to at any point in time. One less agravating item to remove when trying to do something that requires removing the shroud.

He was refering to an electrical load. When he revs the engine to 2000 rpm, the alternator is spinning fast enough to put out its full potential and possibly more since 70amp alts don't stop at 70amps, they may go over a bit more by 5-20amps. Same goes for all alternators.

You quoted 2 sentences that mean something completly different. You quoted your self saying as the rpm increase so does the amp out put, which is not completly true. As the rpm increases from idle to around 1500, the alternator has a higher output potential. 1500 +/- 200rpm and beyond will only yeild the same output potential.

I understand that, and I mentioned it before; however either my english is not as good as I thought or he is incorrect. Reving the engine does not increases the eletrical load on the alt; yes I agree, it will generate more amps, but that is not the same as an electrical load.

He knows this. He also knows the alternator doesn't put out its full potential at idle which is why he revs it to 2000rpm to make sure it puts out its full potential. He never said that sping the alt faster would be a larger load on it, and infact it actually indirectly could. say you have a 70 amp alt, at idle we will say it puts out about 60% of its potential which means it has a potential output of 42amps. If you are putting a load of 60amps on this alt, its no longer going to keep the battery charged, adn the battery will have to foot in the bill to keep up with demand, you spin the alt faster, this will yeild more potential output and increase the spinning resistance as well since it now can and has to produce 60amps.

He is saying here that the alternator output is not ONLY based on RPM.

Here he meant exactly what he typed. Spins the engine (notice he didn't say alternator) to 2000 rpm and then put a load (Electrical load) on the alt because the alternator has a higher amp output potential.

There are a couple of problems with this idea...

First, there isn't a lot of room to make a duct that could properly transition the airflow through a 90° bend and out the side.
Next, even if you could duct it efficiently, the exit through the wheelwell would have to be fairly large which would significantly weaken the car's structure.

Assume though that you managed to overcome the above issues- now where does the rest of the engine bay get air?
Without the airflow through the rad you've got the engine/manifold heat to deal with...ignore that and your temps would skyrocket, especially on a turbo car.

Much better I think to figure out a properly vented hood...

I guess I misinterpreted what he wrote; I thought he was saying that by reving the alt to 2000rpms, he was "loading" it.

It happends :)

Gain power no.. your car will still have the same hp and same tq before and after HOWEVER there is a possibility of acheving more usable hp/tq.. but I highly doubt it.. in theroy I think the change from clutch fan to electical is a sideways move I dont think u will loose or gain anything except more space

Dave

If by "robs", you mean uses a lot of power, I think you made this myth up yourself. I don't remember anyone claiming that. But power generated by the engine is used to run an e-fan, and the same amount of work must be done by the engine to move the required amount of air no matter what fan is used. Most seem to miss that basic point.

I only every commented on the supposed easier access (you still haven't answered my question on that). When quoting me you've changing from easier access to better looks and back again... :Wconfused

There seems to be a misconception on what an efan do; some believe that you will gain HP, and some believe that you will loss HP.

What I've been trying to prove is that none of those are true; granted, by switching to an efan there will be a less than .25 hp loss due to electrical load, then again, by removing the OEM fan you are eliminating 1.5 lbs from the e-shaft, plus whatever drag is created when the cluctch is engaged.

Welcome to my posts from five years ago...

The fan is not supported by the e-shaft, it's supported by the water pump.

But you're not eliminating this load, because like I said, the same amount of work still has to be done by the engine whether you have a mechanical fan or an electric one. You're simply moving the "drag" to the alternator, which is even driven by the same belt.

No not at all. Its both. You think because I post something different in 2 different posts, that means I changed my mind? No, how about letting you know why I also did it.

Are you talking about no matter what electric fan is used or compairing the clutch to an e-fan? The E-fan will take less power from the engine then the clutch. Even a 18 amp flexalite fan rated to move 3300 CFM at zero static pressure will only take an estimated . 45hp with 20% inefficency for both the fan and alternator.

The clutch fan, at 2900 CFM at zero static pressure takes an estimated .90hp. Now
at peak efficiency the clutch fan would be taking over 2hp while trying to pull a little over 2500 CFM. An electric fan will never take this much.

Correct me if im wrong but I don't see how what your saying is true.

I think you're overestimating the efficiency of the alternator and fan. 50% is probably close for most automotive stuff.

Still, if we assume that both fan blade designs are equally as efficient, it takes the same amount of energy to move the same amount of air...Mechanically there is no double conversion loss as their is electrically.

This has been an ongoing debate for years, which is one of the reasons that I made my e-fan myth page....which of course contains all the information mentioned in this thread already. :)

SO what is a good alternator replacement for the FC 70 amp to remedy the E-fan electric draw issue while running a stereo, amps, subwoofers, with an Optima yellow top battery? FD? Same setup? mods? Aftermarket alternator? Would I need an upgrade to my alternator then with the Optima yellow top?

FD alternator is also a direct bolt on.

I was under the impression one had to alter the attaching harness, is this inaccurate?

I, as well, thought there had to be something else to do when swapping to the FD altenator other than just remove/add.

Confirmation? Perhaps inaccurate as well--Verification please.

I thought you were a precusor of just one of them.

That is true, don't know what I was thinking :wallbash:

Agree, except that I had a brain fart and thought that besides the drag of the oem fan, there was also the "weight issue" on the e shaft. I was obviously wrong, and that only leaves what your wrote; which means that there is absolutely no difference between one and the other (in terms of HP).

Only if you have a S4, for the S5 is a DIRECT bolt on swap; this is assuming that you have converted the FD alt pullie to a V one.

So for an S4, there needs to be a V pulley? What is that? What kind of modifications are needed for an FD to work on an S4 please. Thanks!!!

You saying the alternator and fan motor are only 50% efficient?

50% isnt under rated..if anything most engines running right now are only 15-20% efficient compare to their ideal carnot cycle....

raise your hands if your the devils advocate.

look. the stock fan is just fine and works 100% great on the stock cooling setup. if you are going to not drive the car on teh street, going vmount, or anything else besides driveing it like a normal car on the street, leave the stock shit in there. if you complain about the shroud being in the way, then this is a mute point. its there cus it needs to be. thats like saying you removed your balls cus they are in the way and slap around too much. big whoop. grow up.



an efan and the working clutch fan both put almost the same amount of stress on the engine when they are working. period.

I replied specifically to your comment that it made working on the engine easier, and asked for reasons why. You replied that it looked better, which I'd never mentioned and didn't ask about. Your next reply went back to access again (and you still haven't answered my question). Go read it all again.

I'm talking about the fact that the same amount of work must be done by the fan (whatever type) to move the required amount of air. The difference between mechanical and electric will be in the overall conversion of engine power to fan power, and that overall difference is just not worth giving a shit about.

When have I ever said one was better than the other? Most of my e-fan posts have been about dispelling the many myths of their supposed superiority, but I've never made any wild claims about the stock fan's superiority either, other than the fact the it's free and works fine.

Then it's not a direct swap is it?

I don't remember you saying one is better than the other one; however it seems that you only defend one of them, sort of like a bias opinion.



I said bolt on swap; as in no modifications to the alt mounts, alt alignment, or harness. The pulley issue is an obvious problem IMHO.

I gained 15 horses to the front wheels.

Well what do you expect? The stock fan BS posts outnumber the e-fan BS posts ten to one. Lots of people think they know how the stock fan works but actually don't, so they claim non-existant advantages e-fans have, or overstate actual ones.

I have no particular preference for either type. I've used e-fans in the past and most likely will in the future. I have no problem with them, I just don't see any point in removing a perfectly good stock fan based on myths and misinformation. If/when my stock fan's clutch dies I will probably go electric if I can get a suitable fan cheaper than a new clutch. I've said all this numerous times before, so you must have selective hearing...

Don't be ridiculous. Everybody knows a "bolt-on" mod is just that, you bolt it on and it works. If you just take a standard FD alternator and bolt it onto your FC, it will not work!

And that's why I mentioned the pulley; its not hard at all, and its a good investment for those that need to replace their old alternators.

Yes, but the alternator bolts directly onto the engine. :) I should be more specific. For S4 you need to modify the harness. For S5 you don't.

You will also need to swap on the appropriate front pulley.

It's probably a good estimate for the alternator anyway. The fan motor might be a bit better but in general automotive electrical stuff is abysmal. Alternator efficiency is rarely good, especially when you are talking about a 20 year old design. Just put the alternator under high load and feel the heat that thing generates...Automotive electrical motors generally have few poles, bushings instead of bearings, cases that align poorly, thin windings, etc.

Keep in mind that a high quality electric motor will have efficiency in the high 90s.

We're speaking of the alternator and motor, not the gas engine.

I already answered your question both times I replied to you. Let me quote myself,
If I have to remove belts, or remove the front cover for any reason, or remove any of the pulleys, the water pump, etc. I don't want to have to remove the shroud plus the fan to do so. Which comes from both quoted posts above.

I already answered your question 3 times now. You going to come back and say I didn't answer it?

I won't touch any of the arguments about steady-state power drain, but one thing that has not been mentioned is that the electric fan does eliminate the inertia of the mechanical fan (difficulty for engine to rev.) The alternator has a fixed rotating inertia and this does not change with load, allowing the engine to rev more quickly, even if the power demand is the same or more.

However,as other have said, try driving an FC in the rain with headlights, rear defrost, A/C cranked and front and rear wipers running and then tell me that you want more electrical load on the stock charging system.

(If you install an electric fan, please upgrade the charging system.)

As to overdriving the alternator... please do not consider this as an option. The alternator rotor is large and heavy and is already spinning very quickly at redline. If you overdrive it, the rotor may fail (catastrophically) at high engine speeds.

(By the way, I have the stock clutch fan in my car and will keep it, even though a friend gave me a free Taurus fan and controller.)

What is the pulley modification or swap needed to upgrade an S4 Alternator to an FD one? When you say harness, do you mean some slicing required for the S4 harness to work on an FD alternator? I need an new alternator 'cause I am running a stereo, amp, subs and would like to know the answers to making the FD alt work on the FC S4. Thanks ahead.

I highly doubt your stereo uses 90 amps, you probably mean 90 watts, which is much less.

Personally, i'd rather listen to my engine rev that my clutch fan when i'm stopping somewhere, and also the fact that when you're standing at a light or whatever waiting to launch it doesn't use as much power.

The alternator pulley weighs less and has less drag than the clutch fan's weight and drag, when it is on.


It gets in the way and it's annoying to hear, infact we have a saying around these parts, yup, feel the wrath... OF MY CLUTCH FAN. It just sounds retarded.

But anyways thats all just my opinion, and if i come across another e-fan i'll be putting one on my fc.

Well it has been mentioned in almost every thread about this deal. Why not sticky one of the 900,000,000 threads about this same subject so we don't have to keep repeating our selfs?

S4 & S5 RX-7s use the V shape belt, just like in this picture:
https://i62.photobucket.com/albums/h...CT5712-web.jpg

3rd Gen RX7 use the rib style belt(sorry, couldn't find a better pic)
http://images.cardomain.com/member_i...337_1_full.jpg

The S5 and FD alternator use the same harness, as the S4 is different; you will need an S5 or FD alternator plug, and convert your S4 to the newer style.

No, it is a 90 amp sound system ;)

Interesting. Thanks.

Now going back to the part where the engine power consumption will be the same to move the same amount of air. Wouldn't this also depend on the blade type and angle of the blades as well? I can't see the electric fan consuming over 2hp to move 2500 CFM of air like the clutch fan does at peak efficency. Most fans moving this amount of air consume about 15 amps. Even doing the math for 50% efficiency it doesn't add up to 1hp. Yes I know 1 hp is not even measureable really and nothing to worry about, but to say the consume the same amount of power to move the same amount of air, I think is incorrect.

Just my opinion.

1000watt system?

900 rms, its actually left overs from my car sound days ...

BS. You've never once mentioned the front cover, pulleys or water pump. But why on earth would you need to removed these items regularly? Something must be very wrong if you do. This is exactly what I mean by overstating the advantages.

No, you didn't. What I asked was what regular tasks would actually be made easier without the shroud there?

Go back and read it again (post #78, para.2).

The 89-on alternators need a constant power supply, whereas S4's need a switched supply. This needs to be changed to use an S5 or FD alternator on an S4. This schematic shows the difference and what you need to do.

Alternator schematics: https://www.rx7club.com/attachment.php?attachmentid= 199213
Alternator pin-outs: https://www.rx7club.com/attachment.p...hmentid=170065

900W / 14V = 64A, not 90...

I thought I said RMS :wallbash:

Besides, only cheap amps are rated\measured at 14V; you haven't been on the car audio industry have you?

No shit, but I have mentioned it would be easier to work on IF I ever had to remove those items! I don't remove them on a regular basis but I don't even want to think I have to remove the fan and shroud just to do so! WTF is the big deal?

I must have missed that sentence somewhere. Cause I don't remember reading it, but looking back, I did miss it and to answer THAT question, NONE.

Didn't answer my question. My point is that you first said whatever fan used, it will take the same amount of power consumption to move the same amount of air. Now if the clutch fan moves 2500 CFM of air consuming 2hp. I don't see a 110amp fan do you? Then you say the overall difference between the two which contridicts what you said in your first sentence in post 78.

My head hurts....Calgon, take me away

Hey Guys,

When my car was idling really low because the intake temp sensor had failed, if you tried to start it on a cold nite and cranked the headlights and pulled off the engine would die, thats how much load the alternator can put on the motor, but u will only noticed it when ur motor aint in perfect health like mine was, but this e fan will most likely pull nothing we will noticed just like the clutch fan.

Either way you look at how ur fan is setup its going to draw energy from the motor in some way, and difference is going to be unnoticable to you, a full tank gas would make more of a difference in making ur car slower. Bottom line if it aint failed it aint need replacing. NZ convertible said it best, if the factory one fails look into a e-fan as you do gain some serious space in the engine bay.

I hope we havent confused MindSpin311

Cheers

So when you say "cheap amps", you mean those by Alpine, Sony, Rockford Fosgate, Infinity, Kenwood, Clarion, JBL and probably many others who all rate their amps using the CEA-2006 standard, which requires power to be measured with an input voltage of 14.4V.

Even if your old amps are rated at 12V, 900W / 12V = 75A, so you're still wrong. Again.

Exactly! Removing the fan and shroud to work on those items is just not a big deal. It's easy and takes about five minutes, so I just can't see any worthwhile advantage from permanently removing them.

No, that's not what I said... :rolleyes:

Maybe you need simpler terms. If fans, alternators and electric motors were 100% efficient, it would require X amount of work done by the engine to move the required amount of air, whether the fan was mechanical or electric. But fans, alternators and electric motors aren't 100% efficient, so it actually takes X+Y amount of work done by the engine to move the required amount of air, where Y is the engine power that overcomes all the combined inefficiencies of a particular set-up. My point is that Y for a typical electric fan is not different enough from Y for the stock fan to give a shit about. Simple as that.

My, what an entertaining three pages this has been.

One thing I haven't seen mentioned yet is when e-fans are typically installed...and yes, this completely sidesteps the question/debate over relative efficiency but seems like a practical issue to raise.

I suspect that fans are rarely changed without also swapping in a new, and typically more efficient (i.e., higher capacity), radiator as well.

When I built up my 240Z the stock single row radiator got shitcanned in favor of a three row Nismo competition unit. At the same time a dual fan electric setup went in controlled by a thermoswitch from a Saab 9000 (they come stock with a adaptor that splices into the radiator hose and are easily and cheaply available in junkyards).

This setup was so efficient that the fans rarely kicked in- never in the winter and only after prolonged idling in the summer. When the car was shut down the fans would kick on for a few minutes and then stop.

The combination of e-fan and larger rad seemed more efficient since the constant (minimal) parasitic drag of the stock thermo clutch fan was eliminated and the electric fans were usually idle.

When I get around to replacing my stock original radiator I'll probably go for a similar setup as the Z although I expect the e-fan to work more often due to the elevated operating temps of the rotary engine compared to the lower revving straight six.

So basically it would seem more practical to discuss the relative merits of the fans if the upgraded radiator was included in the equation as well.