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You know...I had kind've partly forgot about that other fan. I had bookmarked the C7 fan and not the Malibu one I mentioned in the fan thread, so maybe I had done more reading and decided against it. I'm sure it is 6 one way half a dozen the other. Both would be plenty of CFM. Maybe a little more $$$ for the Corvette fan. Ended up getting it OE new for $300 shipped.
ahh. I haven't measured anything on the 3rd Gen. the little it's run, I haven't seen any heat with the stock 2 fans, no shroud and a auto parts store radiator from like 15 years ago haha.
crazy they didn't even have a shroud back then, just two fans hanging in the air an inch from the radiator. that old r12 must have not needed much airflow across the condenser compared to today's stuff.
looking forward to seeing how you mount the c7 up. do you have a aftermarket aluminum radiator?
funny I have one of the old Ford 2 speeds on a shelf for it. picked it up for another car years ago, and kept it for this one if I ever needed it. it's taking me so long to get it out of the garage what was the common swap has passed me right by to brushless haha.
Yeah I am currently running the Mark VIII, was running the ford 2 speed before this one. They worked well. But this is now twice I have had issues with either the relays or fan itself. Not to mention they pull SO much amperage.
I've got a 3 core (?) aftermarket alum radiator. Some cheapo unit that I am not really a fan at all of. It doesn't fit right, doesn't even have the correct angled radiator cap so it knicks my hood. But its done its job I guess.
Looks like the fan assembly will already be getting here today from Amazon (Ac Delco direct). Next day shipping with the base prime shipping!
Alternator will be here tomorrow looks like too. Only thing I will be missing for fan install will be the main fan connector on the vehicle side of the harness. Which it shipped today.
Depending on how things go next few nights with jetski business work I might get some time this weekend to at least try and install the fan assembly and possibly alternator.
I can move the car around at the house as needed without a fan if I get it partially done and end up waiting for more time/parts.
might drop the alt on first since it's just one longer bolt and a little opening. if you happen to have a DC amp clamp. be cool to see the difference before and after the fan swap.
I sure don't have one. My plan was fan first, that way I could see what my warm voltage is with the new fan on (maintaining normal running temp). I would imagine it would be higher than before.
But with the way I typically work and my availability to work on my own stuff I will likely try to do it all at once lol.
ahh. yeah that would tell too if you don't see the voltage sag.
I got a cheap Amazon DC. amp clamp years ago for work, and I find myself using it all the time for stuff. but don't let me spend any more of your money haha.
I may have already posted this can't remember. the c7 fan draw.
Well...ended up having two late drop offs last night so I was able to spare some time to the Trans Am. Like I mentioned the fan assembly was delivered yesterday, so I pulled the old one out and started looking at my options.
Here is a comparison.
I will note that the more I deal with this radiator the more I hate it. Way too big for a clean install on this car. That being said, I was able to install the fan with zero modifications to the shroud. Only thing I did was drill a 3/16 hole through the aluminum radiator support I previously slapped together into that top tab that sticks up. I then screwed in a large hex head screw that I had laying around from a Seadoo Spark that is used to bolt the plastic hull together at the seam. It has large/deep threads specifically for holding plastic parts together. It bit right into that tab and snugged up great. I put a small spacer between the aluminum and the tab to make up for the 3/8" gap. The bottom of the fan shroud is secure as well. This is very similar to how I mounted the MarkVIII and Taurus fans previously.
I have some 2"x2" foam to install around the radiator to fill in gaps still yet. Now just waiting on my connector to wire up the controller and power/neg cables. I will just be using a fused main power straight to battery.
I actually thought the fan assembly would be bigger then it is. The dimensions I had found online must have been the overall dimensions and not the actual shroud dimensions...time will tell if that becomes a problem.
I think it will be more than enough coverage. you could probably go back to a factory replacement radiator now if you get tired of the big one.
just for reference, here's a pic of my buddy's c7. even stock it doesn't cover the full rad.
my c6 radiator thou, is much smaller and it almost covers the full thing. it cooled well even at track day beating on it all day in hot Florida Temps. not sure how that compares to the said to run warm 406 Gen 1s thou.
looks like it fit in there nicely thou. I had to cut that top mounting point off mine.
the factory c6 fan doesn't conver much either and almost no shroud to it. gm things I guess haha.
I wanna say I've read it's a 400w brushed. but it could be less. it did fine for what it was, I was mainly doing the c7 for the lower amp draw for the alt to keep up at idle on hot days. I had it set to a lower amp draw vs temp to try and keep it from running off battery idle. but it was mainly the ac that needed the airflow, not the coolent Temps, so I ended up with the 220 alt and letting the ac run the fan as hard as it wants. newer ecm things haha. they have a high side pressure vs fan % map.
and just for reference how small the radiator is in that car. the whole thing is 10lbs of crap in a 5lb bad lol.
That is wild. If those cars are kept cool with just that, I shouldn't have any issues with even just a 2 core factory replacement.
I've harped on this in several cooling issue threads, but it really is true, airflow is the critical issue when it comes to cooling systems. Lack of airflow can account for a significant number of near stock thirdgens with overheating issues.
100%. there's a trend with the c6 guys that are supercharged, they overheat like crazy, they have to run a rad with the top 2 or 3 inches removed for pipe clearance from intercooler over the top of radiator to TB, dewitts is a big name in radiators for them. they sell a kit with thicker radiator, dual fans that drops in replacing the one big one. thing costs crazy, like 2500$, was still brushed and didn't really fix anything.
after guys started switching to c7 fan, they also tried going back to the thinner oem radiators, they were seeing better Temps in traffic, and better ac.
I do believe airflow is everything. I like the little swinging trap doors too for highway speeds. I feel like if you get the pwm box set right, at speed it might slow right down to almost not being used even without ecm cut. I'm still curious if you can use the temp sensor that comes with the pwm box on the high side ac line, so the fan doesn't have to run max anytime the ac is on. I guess not that it matters with the big alternator thou.
The controller does have a second AC trigger option to use +50% duty cycle added to whatever percentage is being "commanded". So for example if I hop in the car to go somewhere and its 90* out with 90* coolant and turn on the AC it will go to 50% because it is commanding 0% (fan off) at that temp. Then once the car reaches operating temp the fan will always be 50% above whatever percentage would normally be active, until the AC is turned off. So if 180* is typically 25%, when AC is on it will jump to 75%, so on and so forth.
AC system updating will be waiting till next summer regardless so time will tell on that. You're right, if the alternator upgrade works out it is a wash anyways.
@??? Alternator was delivered yesterday. Question, when you turn one of those by hand do they act odd? It isn't a uniform feel when spinning. Almost like it has a clutch mechanism in the pulley? Hard to explain.
if you have the pulley like the 180amp one in the pics sitting in the bracket. yes they have a one way clutch style pulley. takes a specific tool to remove. the 220amp one I used on my other car has normal looking pulley and it spins the same both ways.
this is the one way clutch type. I honestly don't know why gm uses these on some setups but not others.
I'm guessing you got it off one of the ebay sellers? I think they are salvage yards? the first one I got looked like what the listing pics had up and had the right part number I was looking for. the 2nd with the clutch, have no idea what application that came off. but the part number came up as 180. so I call it that, not that it matters, since 180 is more than enough and super expensive if you went with a aftermarket one modified for that kinda power like from mach man or whatever that big name in aftermarket Billet alternators is and I think these are still more reliable. that and I ended up with 2 for free haha. have been curious for a while what gm put the clutch on for.
Yep it came from on of those salvage yard sellers. Here was the listing title: 220 Amp Alternator 13539728 KW5 for Sierra Silverado CT4 CT5 19-22 2618484
Well I installed the alternator tonight. Zero modifications to factory mounts so easily reversible. I made a small adapter plate to mount the top bolt. Used some spacers (thick washers) to get alignment as close as possible. Need to purchase a longer belt to finish and test.
oh wow. yeah your case is totally different than both of mine.
glad it still fits without much hassle and man I really wanted those valve covers but I don't think they will clear the super ram runners. they budge out alot.
both of mine have this style thur hole mount on both sides. fits in the bottom and needs a longer bolt at the top. not that it matters looks like you got it sorted. Just for info.
So I’m not so sure about this alternator right now. The pulley is wrong for the factory belt. Too skinny. It also doesn’t seem to be achieving its “default 13.7”. Heck I’d argue it’s putting out less than the factory alternator.
With just my HVAC fan on 3/4 speed (full speed relay shot) and my headlights on I was seeing 12.8V. Cant test with cooling fan because the new setup isn’t wired yet because I’m still waiting on the connector. With nothing on I was seeing 13.1. This thing should be more than capable of keeping a solid voltage with that little bit of accessories on.
I’m half tempted to return this and get either new or one from a Silverado and not a Caddy. Bad eBay listing details, should’ve paid more attention.
yeah that's awful. it's not a 6 rib belt? I didn't pay to close of attention to the one I test fit with the clutched pulley. I will have to look again. I didn't know gm used anything but 6 rip. weird.
for the default, it is at the the alt stud? there's no sensing drop across the wirings, but that does seem like a lot of drop. maybe check the voltage with a meter at the stud to case?
I think returning it is a good idea honestly. I don't think they test these things. my seller was good to deal with even thou he sent me 2 different ones and neither matched 100% the pics haha. I'll try to find his store link https://www.ebay.com/itm/23438288945...mis&media=COPY
part number of the one I like better with the standard pulley.
13536552 seems to be a nicer fit too.
sorry it's not working out, I was looking forward to it being a sweet drop in upgrade
Got a response back from seller. They said to just open a return and they will help me out. Good thing I set it up to be able to return to factory lol. Will have to reinstall old alternator in meantime to get it out of the garage. I had kicked my wife out of her spot all weekend.
I've ordered a 220 alternator that looks like the one ??? posted. Same seller on ebay and actually cheaper than the first one I ordered. Just counting the ribs on the pulley it will fix the issue I have with the belt not fitting the first one I got.
Last edited by dabomb6608; 09-23-2024 at 10:14 AM.
your voltage got me wondering if this old wiring has that much of a drop, since the stock alt I believe does control the output based off one of the wires in the black plug. maybe it's outputting pretty high v when unloaded.
I had hopes of finding time to start mine and do some poking around with a meter, but I didn't get time.
my c6 was 13.78 at the alt stud.(after upgrading wiring) 13.6 to the battery and by the time it made it to the bcm and then canbus to the dash it was saying 13.4v on dash. battery is what mattered to me, since I have a new Optima agm and didn't what I under or over charge it shortening it's life. since they are picky compared to a standard flooded. after I added the controller I upped it to 14.4 at the battery itself.
Man when it rains it pours...I've got good news and bad news.
Good news:
Fan is installed. Holy cow does this thing move some air! Wiring up the PWM controller was very easy. Spliced right into my CTS temp sensor wire for the input. I have a 180* thermostat so set low speed to that and high speed I set to 195*. I don't have AC functioning but wired it into my compressor 12v (dark green) trigger wire. It is normally grounded so worked perfect for how the PWM controller operates. I ended up just using a key-on 12v signal to power the controller. ECM fan trigger is unused at this point. Might change at some point but will see how it works as is.
Bad news:
While letting the car idle in the garage to warm up I noticed that I had some smoke coming out the tailpipes. Seemed to progress as it warmed up. Blue smoke too... I was a little too preoccupied with the fan controller to really do much looking but when I moved the car out of the garage I pulled the dipstick to check for blowby and didn't notice any. I think it's either my recent PCV/fresh air changes or a issue with the heads. I don't know the full history on these heads in terms of valve guide condition. They were purchased used locally. I probably should've had them checked out when I had the motor apart but didn't. It could also be valve seal related. I had some pretty tight clearances with the springs and seals when I did those. To the point I couldn't use the Edelbrock brand seals that originally came on the heads.
Other news:
Since I had to return the one alternator, I reinstalled my old alternator last night. Good data point for the brushless fan conversion, I seemed to show higher voltages with this fan setup than the old fan setup. Heck I was showing higher voltages with the cooling fan running than I was with nothing running on that alternator I am returning. I look forward to seeing what the new alternator I have on the way puts out.
With regards to the wiring you mentioned above ??? I do have a upgraded alternator wire between it and battery. Pretty thick gauge too. It is at least as large as main battery cables.
Here is a video of the fan activating high speed. Notice the soft start function. This occurs every time the fan is activated and is a hard coded feature of the fan itself.
oh man.. I hope it's just sucking some oil in somewhere. do you still have the mechanical pvc valve in the valve cover? that and a fresh air inlet is about all thats needed.
I had some guides replaced a few years back and it was half what I paid for the heads. I almost didn't do it and just bought new ones. but then what would I do with these. no one would buy them with bad guides and they aren't popular anyways.
good that you've done some wiring. I haven't touched the alt stuff since back when it was a daily driver forever ago. I noticed it looks like bearly a 10g with a thin ring terminal crimped on. Definitely not good, my ls3 car has a 8g factory. but it is a much longer run and they put a 14g fuseable link in it. so it wasn't great either. almost a full volt drop a across that thing. atleast this is only a foot or two.
glad the box it working. it's still in my cart, I gotta hit buy now soon. I still have the c6 pwm controller box, stock it has a brushed fan speed controled by a pwm from the ecm. my thoughts was wire it to the oem fans for the soft start for now until I need more cooling.
I did see they make a few different boxes for speedo Cals and tach. I wonder if they would make one for the alt that would adjust to a reference voltage, say fuel pump or maybe injectors. since injector offsets are hard to find on older stuff and make a huge difference in the tune. maybe it could keep the voltage constant and avoid that tuning hassle.
glad it's up and running. you have been busy. enjoying to following along.
oh man.. I hope it's just sucking some oil in somewhere. do you still have the mechanical pvc valve in the valve cover? that and a fresh air inlet is about all thats needed.
I had some guides replaced a few years back and it was half what I paid for the heads. I almost didn't do it and just bought new ones. but then what would I do with these. no one would buy them with bad guides and they aren't popular anyways.
Yeah I have a regular PCV going through a catch can and a fresh air inlet hooked to the port in front of throttle blade on throttle body. If anything I should be sucking less oil in now compared to how it was setup before the catch can and baffled grommets. I will revisit those those before doing anything else, maybe the holes I put in the bottom of the grommets aren't flowing enough.
I really hope it isn't guides. That is exactly what I have read. Expensive to replace and then you almost might as well buy new. But who buys Edelbrock Performer RPM heads these days let alone a pair with bad guides...
I did see they make a few different boxes for speedo Cals and tach. I wonder if they would make one for the alt that would adjust to a reference voltage, say fuel pump or maybe injectors. since injector offsets are hard to find on older stuff and make a huge difference in the tune. maybe it could keep the voltage constant and avoid that tuning hassle.
I had sent them a message about it. They said the fan controller could be used for the same purpose. Here was a back and forth we had discussing it:
"I don't have info about the brushless GM alternators regarding frequency, but if they'll take 100Hz, you could easily adapt an FPM to do that by setting it for 12V input and giving it a tight voltage window. The FPM doesn't care a bit where its signal voltage comes from."
"According to this thread I believe it sees a 128hz signal. Not sure if 100hz is "close enough" or not.https://ls1tech.com/forums/conversio...hrow-away.html The L pin is the command voltage pin. A 5V PWM signal is sent from the ECM/BCM at a frequency of 128hz. If the duty cycle is less than 10% or more than 90% or just plain not connected, the alternator will go into default mode and put out about 13.7 volts. Enough to keep your car running, but not enough to charge the battery well. Here are the voltages and duty cycles:10% = 11.0 V20% = 11.56 V30% = 12.12 V40% = 12.68 V50% = 13.25 V60% = 13.81 V70% = 14.37 V80% = 14.94 V90% = 15.5 V"
"The FPM has a 128Hz setting for the C6 Vette fans. I'ts 5-10-90, which should work fine since it will never turn off. To use it for your alternator you'll need to feed it the thresholds using a potentiometer or adjustable power supply. Set it in a tight 0.2~0.4V window around the target output you want."
If I am understanding our discussion. They are basically saying use a 12v input source (say from fuel pump or injectors) and then set the low and high thresholds to a close range like 14.0-14.5 using a external power source for setup. Once set it would then run the alternator PWM output as if it was the fan around the %/duty cycles of the alternator to maintain that voltage range.
huh. I'm not fully understanding what he's saying. I'm guessing he's talking about the 12v triggers for the fan speed? like 1 wire gets 12v from the ecm for low, and one for high? not sure how a potentiometer would get you that from a single 12v wire that goes from say 12v-14v under load?
either way, it might be nice to use as a boost mode. the new ecm's have over ride boost mode in the code. usually if the high beams are on, or combo of things all at once it will up the voltage to help everything run. like say afternoon rush hour traffic, its hot and rain hits. you got lights, ac, wipers and basically everything electric on. it will boost the voltage to as much as 15v in some codes. time based so it doesn't overcharge the battery long term too.
so you set it to 14v but fan is max with ac on, it says ok and bumps it to 14.5v to help with all the high current losses?
kinda pricey compared to the little 10$ box and that ls1 thread has a Arduino drawing that I know zero about, but would adjust it spot on, not in steps.
So the PWM controller I have can use 5V sensor inputs or 12v sensor inputs. Selectable via the dip switches. Currently it is setup for 5v input since the CTS sensor is a 5v source.
Let's say hypothetically I instead had a 12v CTS sensor that at 180* was 14.5V and at 200* was 14.0V. The controller would regulate fan speed in that range, but take into account how the voltage is inverted (high temp = lower voltage this is important for later). So cruising down the highway where airspeed is doing most of the work the fan might only run at 10% but in town on a 100* day it will crank it up as temps go up (voltage seen goes down). Now instead of the CTS lets wire the sensor input to the fuel pump 12v source and instead of the fan lets wire the PWM output to the alternator. For Low/High thresholds, remembering the inverted values from before, you keep it a tight 14.0V (high) and 14.5V (low) range. On start up it will read say around 12v, that is well below the high threshold point so it will request the alternator to ramp up voltage. As this happens the sensor input voltage will rise. As this number hits 14.0V and then approaches 14.5V it will start ramping down voltage. At this stage it will begin to maintain that range. Turn your AC on, lights, wipers, audio system cranking, etc. and the voltage will be reduced. As it drops to or below 14.0V it will request the alternator to ramp up to maintain that range.
ahh. I didn't realize it could use a 12v sensor input, I didn't realize there. was 12v temp sensors haha. the potentiometer distracted me, I'm guessing that's to lower the range to get into a eaiser to use band around 12v? knock that 14v down to 12v range to keep the box happy. either way, very cool.
I saw a post somewhere about ebl, but sure if it's flash or p4 that had a switch to look at fuel pump voltage or ecm voltage for injector offsets and someone said it was easier to tune off the ecm voltage since it marched the injector voltage better than pump wiring did. made me think about keeping the injector/ecm voltage constant might make tuning easier. or at least less swing in trims.
either way, I gotta get one of these boxes to play with.
220A alternator from 2020 Silverado is installed. Needed nothing to bolt up other than 1 longer bolt & nut for the top mount. No drilling or anything required. It was a tight fit in that top mount, but it was close enough the bolt was able to pull itself through the factory serp mount with the threads. The 2" longer fan belt I got for that last alternator I tried is a hair too long but works. I will probably install one that is 1" shorter. Voltage on dash gauge holds 13v with voltage at alternator 13.7-13.8v. Voltage at battery 13.5v. Guess I shouldn't be terribly surprised to see that kind of voltage drop in the old factory body harness. The dash gauge gets its reading from the fuse block. I didn't hook up my laptop to check voltage readout from EBL, but will check it next time I start it.
Regarding the voltage switch option in EBL, I want to say that is a P4 option. I don't believe I have seen that option in my Flash. I will likely end up getting either another one of those PWM fan controllers or just the cheap PWM controller to get voltage up at the alternator.
Last edited by dabomb6608; 09-26-2024 at 07:56 AM.
that one looks much better on there. if you want, you can remove that big power stud. if you pop the back little plastic plug out just below it under the stud there's a 10mm nut under it. just if you didn't notice it.
I've only messed with the c6 wiring for voltage drops, never worried about it on other stuff back then, this is a new rabbit hole for me but I looked at the wiring upgrade they call big 3. it also includes grounds, so while I was in there, I upgraded the factory ground locations, didn't add any extra to avoid ground loops but thicker wire and made sure I didn't have any big voltage drops from alt case to block, block to frame while idling with a 100amp load. I'll probably do the same go the old 3rd gen when I start working on it. to many projects not enough time haha.
on a side note, I'm noticing and trying to find more info but it seems some of the hot rod guys and other crazy swaps are starting to try these 12v electric ac compressors. they can hide them behind fenders and stuff. down side being they take lots of power when you need max cooling, I'm seeing 70-75amps. but with that alt and fan, you might just have enough to run one and avoid r4 compressors all together.
oh, there is a company that sells the little pwm box all pre wired up with the right plug for the alt. it feels a little pricey knowing the box is 20$ but time and effort saved is worth it sometimes.
You know sometimes it is cheaper for me to just buy something to make it plug and play than it is for me to step away from money making labor in the garage to do it myself lol.
Definitely never looked into electric compressors. Might have to take a look.
Definitely worth it if it's taking away from your side business. time is so short as it is.
I found these 2 videos.
the vw swap. there's a follow up running video, but they used the fan that cam with the ac condenser for the radiator/condenser, so of course a cheap China fan isn't doing both and it ran hot. that and they ran electric power steering as well, and the alt didn't keep up with both. but when they switched to manual ps, they said besides the engine running warm the ac worked. now is that 100deg outside 40deg vent temp good? I have no idea.
hard to find any good builds and how it's working after. but it all seems to be the same kit, if you get the compressor and controller box, it seems about 400$. and then make up lines and stuff.
my head is thinking about the whole drivers side of the engine with no accessories in the way, a aftermarket k member for clearance and how you might finally have room for a small street turbo kit on a 3rd Gen without gutting the car or making it all horrible to live with. I've had supercharged cars but never a turbo, always wanted one, maybe someday.
09-17-2024, 10:39 AM
