Relying on free air CFM rating to compare fans is not very helpful. Many fans will flow a lot in open air, but when put against a radiator, they do not have enough power. This is why OEM fans are rated in watts, which is a measure of power. A C7 Corvette fan would work way better than the 16inch fan. The Pro-Form fan is rated at under 25 amps at 12 volts, which makes it about a 300watt fan. The C7 Corvette fan has similar dimensions and is rated at 600watts and retails for under $300.

Another great option for the GTO size radiator would be the dual 12" Volt fans. They are 300 watts each and can be found in the salvage yard for $75-125.

Andrew

 

Watts is not a good way to determine airflow either because it leaves out efficiency. Quality of materials and design can have huge differences in efficiency. For example, the Delta PAG brushless fans are 25-30% more efficient than the spal brushless fan found on the C7. In other words, there is more airflow per watt means more efficiency.

Best way to determine airflow is with a flow chart with variable static pressure. This data can be found on most manufacturer's datasheet. Most radiators are between 0.30-0.60" of h20 static so targeting max efficiency at that rate is prudent.

 

So My flexalite flexwave fan comes sat. I also have a CFM measure tool coming so I can test them out of the car (free flow) and then in the car attached to the radiator. I will also test my current fans which are on rad and then I will test them out of car to get some good comparison info. I've been watching as many videos as I can on the flexalite 16" (not the flex wave) and saw one against the spal 16" curved and the flexalite pulled more air as the guy measured static pressure in the shroud and did it varying the obstruction in the front of the rad. Another important thing to note just like all these high output brushless fans is you never really run them at WOT, its nice to have high numbers but you only need what you need to keep the motor at your commanded temp with with whatever setup you have. A massive fan isn't really neccessary unless you need massive CFM. My current setup works fine as I haven't over heated and I generally stay under 200*F but I have about 12% of my rad not covered by a shroud at all. I can't do that with dual fans due to the upper suspension so If I want more I need a large single. I have a new shroud coming from ebay for the 16". I guess if I test the flexalite and its go more CFM than the dual 11" Spal Knockoffs and pulling from 100% of the core then I don't really need more fan or it would be a waste. If the fan doesn't perform better than the dual 11" then I need to look at a brushless or big OEM style but I think an aftermarket 16" Delta or proform 16" bushless would be the ticket. I needed the shroud either way due to the C3 vette suspension being dumb. At least now I can just focus on a good 16" single to drop right in. The Delta being $500 and proform being $180 (if its ever fixed). And since I'm already setup for the brushed on variable speed I get alot of the perks of brushless already. Either way I might have some fan data for you this weekend possibly and the shroud should be here by Wednesday.

 

Got the flexalite flex wave puller today and did a basic test. On the box spaced off 1.5” it was pulling 250w on the motor 18.5-19amps at 13.3v. I then tested free air standing up on its side no restriction and it’s 11.78 amps and 152w on the motor. In free air it’s blowing a good bit of air. I’m going to mock up on a two 1” core rad to test actual pull through the rad getting that data plus wind speed. So far it seems decent for a single 16” at $150-160. I’ll wait till I get some real numbers with the tests against what I currently have.

 

Did some more tests tonight. I unplugged my fake 11” paddle SPAL fan which has its own divided shroud and tested one single fan on the car mounted to the rad. Its a champion 2 core with 1” tubes.

single 11” fan 11.81amps and 153w pull at 1692 ft/min.

dual on would be 24amps.

To remove the fan I would need to move the rad so didn’t want to do that unless I knew I was making the switch. I had a spare rad which is a HOWE 2 core 1” cores on the shelf. I pulled the rad and layed it on some buckets so the core was open 2ft from the ground. I then layed the flexalite 16” fan on and used wood to keep it from spinning on startup. I did the same test as the other fan and came up with…

16” flexalite 14.9amps and 194.7w pull at 1594ft/min

the 16” does sound good tho and they are within 100ft/min rating. Only advantage would be the 16” would pull from the entire core vs the 88% I have now. I don’t feel like it’s much of an upgrade tho. Today I took the car out and on a 87*f day high humidity I was cruising at 40-50mph in 3rd and temps were in the 179-185 range most of the time. So back to the drawing board I guess.

 

What's wrong with driving around at 179-185?? Just how cold are you realistically thinking you're gonna get?? My 91 Z28 with an iron block 370 front mount turbo runs around town on 90-95 degree days at about 210 max. That's in traffic, when I'm in constant motion it drops to about 190-195

 

nothing is wrong with my temps. My issue is when I stop and sit still temps increase from the 179-185 to 199*F ish and these are cheap fans ($120 eBay specials) so idk if I trust them all that much. I figured I could improve the cooling and put a more reputable setup in there. I would also like to cover the whole core which means I need a single larger fan setup. You also have a front mount turbo and mine is a basic camed 5.3.

my 87 trans am has a front mount turbo but I run a larger 31x19 afco racing rad and a big derale dual spal 12” fan setup and I’m able to keep the temps under 190*F for the most part. That also has a 3000 stall and it will idle cooler than my 78 vette which just has a NA 5.3.

 

I don't want to take over the thread but figure this might help someone out down the road looking at using a 16" brushed vs brushless setup.

I yanked the derale dual fan setup out of storage... I thought it had spal fans but it doesn't. They seem to be 11" fans and paddle style just like the Spals. I had them mounted to a smaller Howe dual 1" core rad in storage from a previous setup. I figured the are equal or should be better than the ebay fans which look almost identical.

Derale 11" paddle fan has a 11" DIA opening, 4.5" center hub DIA.

• 2 fan area 190.06 in
• 2 fan center hub area 31.808 in
• remaining area after subtracting hub is 158.252 in
• Single motor on rad 12.21amps, 160wP, 1830ft/m, 21.6mph
• Two Motors on rad 23.18amps, 296.4wP, same speed
• COMPARED to cheap Ebay dual fan specs: single 11” fan 11.81amps and 153w pull at 1692 ft/min

Flexalite wave 16" fan

• fan area 188.7 in
• Center hub 15.904 in
• remaining area after subtracting hub is 172.796 in
• Motor on shroud on rad 14.57amps, 191.3wP, 1692ft/m, 19.2mph
• PREVIOUS TEST no shroud, laying on same rad (dual 1" core Howe) 16” flexalite 14.9amps and 194.7w pull at 1594ft/min

My findings:

• Derale pull slightly more amp and wP with a slight bump in ft/min compared to the ebay 11".
• If you compared the flexalite wave 16" fan (with shroud) to the ebay dual fans with integrated shroud the 1692ft/min is the exact same flow but its doing it with only 14.57amps and 191.3wP
• ​​​​​​​This means the 16" flexalite saw a drop in amps and wP and an increase in ft/min flow due to the shroud which is a 15.5" hole with height between .34-1.125" off the rad core
• Going from the dual 11" to 16" nets me an increase of 14.544in in surface area that the fan covers/pulls from directly by removing the additional fan hub size. I would think this acts like adding removing restriction of flow even though your not adding to the rad core size.
• Going from the shrouded dual 11" to 16" with shroud nets me an increase of rad coverage 68.125" or 15% more/additional rad core coverage/flow area. I would add some high speed flaps to be safe.

Conclusion
Based on the info above, going from the dual 11" to the flexalite 16" could net me a few advantages but no real negatives. I wouldn't call it an upgrade in performance like going to a big Spal or Delta PAG fan but those options are $500+. As already stated my cooling isn't overheating by any means and I already have the flexalite variable speed controller with soft start (60% start - 100%) which is most of the benefits of the brushless anyways (also being thinner and flowing more air with lower amps). I don't think I need more airflow at the moment since I'm adding 15% coverage to my fan setup idk if the additional flow is a necessity. Not only am I added 15% (68.125") to the coverage area by fully covering the core overall I'm also adding 14.544in by reducing restriction of the 2nd fan hub/center section. This puts me at a theoretical 18.5% increase in core coverage/usability over what I currently have while not really reducing airflow/speed through the rad core. While I have this data from the larger Howe rad that probably isn't an exact comparison to the champion core which I assume has less of a restriction on the ebay fans. Generally the cheaper rads have lower fin count so I would suspect a possible bump in numbers from the flexalite flex wave once installed on the champion core. Another thing I worry about is fan replacement and if its worth going to any of the PWM fans. I see this being 2 fold as PWM should last a really long time but failures happen (PAG could be the ECM relay, module or fan itself). So if it does fail I can't just swap it out with a brushed fan which are available anywhere. On the other hand brushed is easier to find but doesn't last as long so...

 

good info. You make good points. In my situation, I’m gonna have to stick with either the program or delta pag because I tried to fit the flex a lite and the body of it was a little oversized and will not fit my shroud. I don’t feel like making another shroud either.

 

I get it. I came real close to getting the delta PAG. Issue is not alot of people run them that I could find on youtube etc. I wish they made a 17" as an 18" is hard to fit. I still might do it depending on how mine goes. If you end up doing the delta PAG post the results and if you have the specialty tools for wind speed and amps/watts get some info out in the world.

 

If its good enough for Devin vanderhoofs car, its good enough for my heap

 

well I returned the proforms and I was trying to work a deal with the delta pag guy, but he stopped responding to my emails. Maybe I said something he didn’t like, I don’t know. But at this point it looks like I’m just gonna get iteration 2 of the proforms when they come out. I’m on a waiting list anyways. I was planning on posting here and ls1gto about the delta pags but I guess I’ll have to scratch that and carry on with the proforms.

 

‘Work a deal’ ?
Sounds like he had better things to do

 

yea probably so. I just didn’t have a grand for two fans. Sometimes you ask for 10% off, they don’t mind if they get a sale. Well, whatever I guess.

 

do they have updated dates on the revised versions? I would for the price give the proforms a shot as well. With the delta PAG idk why there is a 4 wk turnaround.

how are you triggering the proforms? 12v to the PWM sets it to 100% with soft start if I remember correctly.

 

I talked to him around the end of last month and he said he was expecting a batch the middle of this month. I was gonna give it till the 15th and give him a call and see. Well that’s what I’m planning on now since I haven’t heard back from delta pag. It don’t matter to me either way. $169 for a whole new fan if this lasts a couple years, no biggie. Heck I could purchase the 2 year square trade on it and be good for that long. The price point that proform selling them at is not bad. I took one of the motors apart and they aren’t cheap junk. I was actually trying to see if there was an evident thermistor I could bypass but I didn’t see anything. Must be measuring temp some other way. I’m no circuit specialist so I have no idea. I’m just smart enough to get myself in trouble sometimes.

anyhoo. I’m forging ahead with another set of profound when available if I dont hear back from delta. I really did want to give them a try but either way, it don’t matter.


im using my factory wiring to run the proforms. The wiring is pretty thick, I was just using one speed and they do have soft start and I bought a pwn controller as recommended earlier on. My plan was to set the controller at a lower percentage and run the 16” fan on that. When it gets past a set temp, a relay will bypass the pwm and run full speed along with kicking the 12” one on. That was my plan. How that might work is yet to be seen.

 

Keep us in the loop, I would snag one to test if I knew it was the updated version with no temp shut off issues.

So thats what I was thinking on wiring. It needs 12v, ground and PWM +12v I believe? The Term X does PWM- I believe or you can get a controller. I was looking to get one of those $15 PWM generators I see all the time and control it with that but how do you have it set to a temp? So key on you don't want the fan on... so the PWM controller needs to be turned on automatically at a set temp which could be controlled by a relay activated by term x fan output. THe PWM turns on to set 50% and fan activates with soft start and runs at 50%. Then temps increase so you need to run another PWM generator to turn on and switch from the lower speed (can be done with relays I think) and that PWM generator would be set to 90-95% for full speed. Or like you said relay switch to 12v+ to the proform PWM wire which will give you 100%. I don't know if those $15 PWM generators can be turned on and off and remember the previous settings. Otherwise your looking at a PWM+ controller with variable speed which looks like $150-200 to get true variable speed or do something like @LSswap has done in his DIY PWM setup. Once someone mentions and arduino I'm out but if there was a way to create a PWM with the volvo/mazda relay he uses controlled by the term X I would be inclined to do that.

 

im glad you asked. In the instructions it says when you remove power from the pwm generator, it keeps the setting. So I figured I could power it on at a set temp with the factory ecm and then with a relay, kick it to full power when needed.
it actually would be really easy to do. There’s a green wire that’s for the pwm. It to send it a signal, that varies the speed. If you sent it straight 12v it’s 100% power. When I do it, I’ll show what I did unless I end up with the delta.

 

just put a pull up resistor to 12v on the pwm signal line and the holley will control it

you guys are waaaayyyyy overcomplicating this

 

[fan pwm wire]---------------------------[holley pwm- output pin]