When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Is the 75A relay single pole dual throw (SPDT)? If you have a normally open (NO) and a normally closed (NC) on the 75A relay, you could put the high current on the common and the NC lead to the fan's low speed circuit and the NO lead to the high speed circuit. Then use the 40A relay (only energized when you temp relay powers it's coil) to run power to the 75A relay's NC circuit. Put AC control output onto the 75A relay's coil so that when AC is on and demands extra cooling, the 75A NO circuit is energized (and the the NC circuit opens, switching off the low speed circuit). This way it's always one or the other, not both. Who knows, it might be fine powering both low and high simultaneously, this method plays it safe though.
Edit, you actually need the 75A relay to be DPDT, here's a drawing:
Last edited by Toruki; 06-05-18 at 01:01 PM.
Reason: Brain fart. Double brain fart.
Hmm, you may be right Toruki, but I think I may have a simple solution. Just 2 relays needed. My 75 is a SPST, and I have a 30/40 DPST too.
Simple Cooling fan Setup
The only problem I see is that if the temp sensor isn't up to temp, it won't send a signal to the 1st relay and thus the second relay, despite switching to high power mode on the fan, won't have any power. This is really a moot point though as won't the AC running quickly heat up the motor/radiator? My AC condenser is going to be leaning away from the radiator, so it won't share heat as effectively as one near the radiator might, but it will have better airflow and cooling which is the whole point anyway.
So I would either buy another relay, or figure out whether the fan is fine (or not) with both the low and the high speed circuits powered. I'd also see what the current draw is under the three conditions: low speed, high speed, low and high speed. Good luck with it!
I got the fan installed and while it was a pain, it works great! I'm checking my temps with an IR thermometer, and the fan's set to come on when the upper hose hits 180, and the water coming out, is cooled to about 160. I took the car 100 miles yesterday and had no problems until right near home. The fan is quiet, at least compared to RX7 exhaust sounds. it's still quieter than the stock mechanical, and isn't making noise when it's not needed.
Suddenly my volt meter is dropping below 12, the first time it's done that, and the car stalls if it's coasting up to a stop. I got the alt tested today and it's only putting out 11.5 volts! I think the problem is that with the S5 alt, you cannot use a switched hot for the Load wire, it needs to go directly to the battery. This causes .2 amps battery drain at all times though. It's a daily driver so I'm not too worried. I just happened to have picked up a spare S5 alt for my Starion, so it's going in this afternoon.
It's also time for some routine maintenance, tightening some lines, and changing the oil. I'll put up some picks of the install. I had to make some brackets, unlike others it seems, as the fan would not line up with the stock shroud mounts at all. On the plus side, it looks like I'll still be able to fit the AC pulley!
OK this is getting frustrating. I put in the new Alt, and I get the same thing, 11.5 volts on the gauge. I checked with my Multi-meter, and I see between 1 volt and 50 volts, at the output terminal! What's going on here? I've run the Yellow wire (closest to the B+ terminal on the S5 alt to the engine bay fusible link box, so it has constant hot on that wire. That should give it the proper load reading, right? I still don't understand how the gauge on the dash says 11.5 volts , and my meter is all over the place, especially when I rev it. What are the odds of getting 2 bad alternators in a row?
Oh and I did remove the whole fan wiring system, just to remove variables, and I'm still not getting proper voltage.
Which seems to match most everywhere else I can find a discussion of S5 into FB swaps. Would a failure of something in the dash cause an alternator to not put out the correct voltage? I had a bunch of warning lights come on and go off (stopped since I swapped the new alt in), but I put that down to the odd fluctuating voltage being produced.
... What are the odds of getting 2 bad alternators in a row?
...
Not half as bad as you are thinking.
How does your ground wire look? If you are sending the regulator voltage information that has corrosion in the signal (from bad grounding) the alternator will turn on and produce charge enough to push through the resistance of the corrosion. Then when the signal wire tells the alternator "enough!" the corrosion acts like a barrier for the electrons to make their trip. If any of that makes sense.
I was gonna comment earlier but you already decided on which fan to use. I just replaced my wife's Porsche electric fan on her car. And Porsche uses a clever little temp control device which is all self contained. The fans in a 996 just require 12V constant and a 12V signal wire. They automatically adjust for fan speed and contain their own relay and thermo switch. All you gotta do is give them power and they flow fast or slow depending on the air temp. And you can get the fan for $80 on ebay. If I go electric... that's my route.
I figured it out, being the genius I am, I totally forgot to check the fuse between the Alt and the battery. I found the main Fuse had melted! Like sticky plastic goo stuck into the holder.
Replacing the whole assembly with a 100 amp Fusible link type PAL fuse seems to work much better! I found a holder at NAPA, and it required a tiny slotting of the holes on the fuse, to fit.
The new Temp relay/fan and electric sender are working great. The car doesn't go over 190 even at 6k and 30 mph or so in second. Now it actually gets up to temp properly and idles at 800 rpm much quieter. I'm so impressed what having the car running at the right temp has done.
The next project is to figure out why I have no headlights all of a sudden. No blown fuses I can find, but no headlight movement. I suspect the switch.
I also plan to remove the carpet on the floor and install some Reflectix, to lower heat in the cabin. Someone already put aftermarket sound deadening and a new carpet, so those are good to go.
AC is a maybe atm, I need to find a better/correct Condensor, but it's on a back burner. I also noticed quite a few loose plugs under the glove box, and am not recognizing them at all.
That Porsche fan sounds awesome! I'll have to post some pics of my install. I've been so busy just keeping the car on the road that I forgot to take any recently.
It's been a while, but I've since had the car as a daily in the hot weather and it's doing fine. I wasn't! So I added that reflectix stuff and lowered my floor temps by 15-20 degrees! For $16 (10 for the Reflectix and 6 for the glue) I've made myself substantially more comfortable tin the 7.
In other news, make sure that you fuse EVERYTHING. My hot lead for the temp relay got caught in the light mechanism somehow and started a small fire. Thankfully I was just pulling into the driveway and easily extinguished it.
I took this opportunity to pull all the damn emissions crap wiring out of the harness that's in the bay. Now I've only got 3 wires over the engine, Temp, Battery sense, and Alternater output. I removed the hot lead to the carb solenoid and have so far experienced 0 issues. It's just coiled up for now in case I need it again. The engine bay is so much cleaner I'm amazed, not to mention it was full of janky wiring, that someone else had done before me.
Relays for the Fan
I guess the last thing, might be the hardest, I'm seriously thinking to sell the car. It's been so much fun, but I really could use the money! Where is there a sales forum on here? I'd like it to go to someone who knows rotaries and not some kid who has more money than sense!
It's been a while, but I've since had the car as a daily in the hot weather and it's doing fine. I wasn't! So I added that reflectix stuff and lowered my floor temps by 15-20 degrees! For $16 (10 for the Reflectix and 6 for the glue) I've made myself substantially more comfortable tin the 7.
The local auto upholstery shop near me told me that's what they use on all their builds and said it cuts down like 90% (can't remember the exact number) of the heat inside the car, and it's CHEAP!! I put in in the ceiling of my car and all over the floor and firewall. I'm prolly gonna put some in the doors too!
Sad to see that you're selling. I hope it goes to a good home also. Too bad we're so far apart!
Well car is as good as sold. A kid who actually wants to do a full resto is buying/bought it. Just need to sign some paperwork. I'll leave the thead up, for the technical bits.
So now that the car's sold, I can go find a Repu! The original reason I wanted to get into rotary anyway...
I hesitate to mention this, but my curiosity is killing me... The RX7 is slow. Like 100 hp slow. I don't get it. I've got some pretty big ported scondaries, plenty of fuel and air, and yet get blown away by Camrys? I'm thinking timing, less advance would help, but beyond that am at a loss as to why the car is so dang un-fast. I'd like to help the kid out who bought it, as he's totally non-knowledgable on carbs. Might even buy it back later!
Clogged up cats on the stock exhaust maybe. My all stock car couldn't get out of its own way until I put the full RB long primary system on it. Still not very quick though. You can get a Camry with 270hp now. A street port isn't gonna help you race away from stop lights when you're competing with that amount of power.
It feels odd talking about someone else's car lol.
Anyway, it's got 2.5 inch pipe. Just the pace setter header. Straight to a brand new 2.5 inch Magnaflow Cat. 2.5 inch Vibrant Resonator, and 2.5 Magnaflow big-*** muffler. Very loud. I had to run a 2-1 header to collector due to my state's requirement for a cat. Otherwise I would have run the RB system.
It had good compression 90-95 at cranking cold. Started easily when hot too, as long as you waited for the carb to fill with gas. Carb is tuned to roughly match Jeff20b's thread. Cut venturies, blocked air bleeds, less fuel secondaries, but more on primaries.
It was the dang 4-cylinder Camry, late 90's which makes it pretty embarrassing. I did pull away at 55+ though.
I suppose the lesson learned is to go turbo! Meets emissions, and makes a lot of power, comparatively. Otherwise I would have done a large bridge port and something wild...maybe a turbo too. Oh and get a 75 or earlier Mazda so I can skirt emissions.
06-05-18, 08:05 AM
