ajrothm

So I just received my new Dewitts 17" Single Spal brushless fan and custom made shroud. This is the first one they have done for a C5 on a cut down Dewitts radiator with fitment changes for a blower. They did a great job on it.





Fitment is great, I actually have more room every where around the blower then I did with the dual 12" Spals.












Hose adapter and temp switch install





Ofcourse I'll be covering that up with the protective accordion sleeve.

I still have to finish the wiring, get some materials for sealing gaps in the radiator/frame and seal everything up real well. Hopefully in 3-4 days I'll have it all done and ready to test it. I'm optimistically hoping for 10* reduction in temps...I'll be a bit disappointed if I don't get atleast that much but.... at this point, I'll take what I can get.



Now for the back story on my cooling issue that I believe plagues a lot of people with FI vettes, especially in hot climates.
My car has always ran hot since I put the iron block 402 in it and running the AC... Anytime its idling with the AC on for more then 15-20 mins on a 90*+ day, it starts heating up. Catch a couple long stop lights after a freeway drive and its at 225+.... It easily hits 235*+ on a 100* day, at which point I can turn off the AC and stop the temp climb. It will eventually start to cool down at freeway speed but takes a decent amount of time.

My system consists of:
Dewitts cut down radiator
Dual 12" Spals
160* stat, (its new and its fully open by 178*)
New GM 2004 LS6 water pump
1 Gal of antifreeze to 3 gals of distilled water (25%/75% mix)
Top radiator shroud in place
New air damn on the bottom.
A&A ram air intercooler that's mounted low and forward
2500* Pure ceramic coating on the headers
License plate cover opened up for air flow to the IC
Earls 25 row oil cooler

So this thing should run plenty cool with this hardware right?..... Well.. Maybe not...

ajrothm

So I believe my main problem is 10lbs of $hit in a 5lb sack...

I only have about a 2" gap between my condenser and intercooler. This is due to the fact my cradle has been modded for more inlet clearance to the blower, so the bottom of the radiator/condenser sit farther forward towards the IC, allowing the top of the radiator to lay back more (this in its own hurts cooling efficiency).. I have a small 2" gap to bottom feed the radiator from, the air damn is directly under this gap to direct air flow upwards.



Therefore when idling, the fans have to pull air through the radiator/condenser, by way of the 2" gap and having to make a hard turn into the radiator. When the top shroud is on, there is just no where to pull air in from.



Top shroud installed... Seals off the top pretty tight. Therefore air feed to the fan is soley from the bottom gap or what blows through the IC. It doesn't help that this blower is a huge vacuum cleaner, no doubt sucking in air and disturbing air flow to the radiator at higher speeds (more rpms).


I do have the front of the car opened up and the license plate cover is cut open to allow a straight shot of air flow to the intercooler, however this isn't helping at idle/low speeds as the fan can definitely NOT pull air through the IC as well.

I am hoping the higher restricted flow capacity of the brushless fan will allow it to pull more air through the restricted 2" gap, and possibly suck air through the IC IF the whole radiator area is sealed off well, which will be task 2 of this project.

b16gsr

in on 1

95wht6spd

Looks nice, same idea as the original Procharger kit, of course with better parts. What is the CFM compared to the duals?

JT FRC 00

looking forward to this setup! Subscribed

robert miller

You did mean to say 15 lbs of shi* in a 5 lbs of space.

I love the space in the c7 I will be putting a small blower on the c7 but will only be doing and really keeping this car 650 rwhp & about the same on rwtq & calling it a day with the 1 7/8 headers & 3 inch mid pipe & meth on it.

By the way love the looks of every thing on the car..

leo12

made a set up in the same fashion with a brushless spall fan and it still ran a bit hot switched the fan to a SPAL 30102113 16" ***Extreme Performance Fan Curved Blade race car fan.16.30"max CFM 3000
26 Amps and took care of the problem,good luck

LedfootLarry

Have you considered moving the intercooler forward,
cutting rebar , and mounting it up front , and getting a
Tigershark front end

ajrothm

The thought did cross my mind about relocating the IC in front of the front cross member...I'm not sure how it would fit with the bumper foam .. Definitely something that may happen in the future.

As for the Tiger Shark nose, I don't care for how they look so I'll be sticking with the stock nose and try to make it work.

Blackonblacksls

Every time I see one of these threads I'm glad I never used a blower or turbo on any of my vettes.

Good thing is, yall are bringing a lot of solutions and nice parts to the table for everyone else...

ajrothm

Yeah... I'm with ya... I've often thought about going back to a H/C LS7 and just live with an honest 600 rwhp NA, put a stick back in it and just cruise it reliably and still run with some cars.

Less really is more sometimes.

4DRUSH

Using the stock wiring to control a relay? Aftermarket fan controller?

How many amps will it draw?

venomws7

Looking forward for the final results and good work man.

How much wider is the old Dewitts cut down radiator over the new one ?

robert miller

It is not a problem with a blower r turbo on the car at all. The problem has always been going hog wild & pig crazy with what ever set up. ALWAY HAVE TO HAVE MORE POWER R MORE THAN THE GUY NEXT DOOR.

My new car will be headers meth and a SMALL blower keep it around 650 rwhp & have fun with the car..

ajrothm

The harness comes with the fan, however there is no external relay. The soft start motor controls voltage spikes on its own. It gets 12v power, 12v switched, input from the included temp switch, an override input (toggle switch activation/AC), and a ground.. It's a very simple setup to wire. However it would have been nice if it had at least come with an inline fuse for the 12v constant power circuit.

The temp switch is 165* on/185* off and just screws in an adapter that goes in the radiator hose.

I'll get back to work on it tomorrow.

ajrothm

A few pics of the next leg of my mission, in planning... To seal up, shroud up the radiator and IC to direct air flow. Also may open the entry into the IC from the bottom a little more...

First off, to seal up these gaps around the radiator, also may build some shrouds to direct the air into the condenser smoothly.





Possible sealing agents...


Now for air flow entry management... This is the current opening






Lots of open room but no direction for the air flow to go... It just blows in and goes anywhere...




I may try to shroud in the air flow to the IC directly from the front openings... Try to "funnel it" into the IC... This part of the project may come later...We'll see.

Definitely going to open up this gap that feeds the IC... I'm going to make a new bracket to attach the bodywork where it "rolls up" to feed the IC and roll it up more. You can see here I have plenty of room to roll this piece of plastic up to increase the gap and make a new support beam.



All of these mods will only help high speed cooling but its definitely something it needs as well.. Especially on these 100*+ days with the AC on and its running 220* on the highway...

ajrothm

I got the fan wired up and working today. Did some preliminary testing.

Fan starts at around 172* on the DIC, it starts slow and slowly ramps up, I suppose based on the temps it sees. Once its at 190*, the fan seems to be on full speed, which took about 5 mins to get there with the AC on.



My very scientific testing seems to show the fan pulls a decent amount of air, even in a restricted environment:

Even pulling this paper to the IC which is a good 7-8" away from the condenser at least.



However, after idling it in my garage (90-92* ambient), on jack stands, with the hood open about 4" (couldn't close it do to the charge pipe sitting on the intake for the IAT sensor), it still managed to heat up to 234* in about 22 mins of idling with the AC on... No doubt, it would have kept climbing.

The fan was blowing a good amount of scolding hot air out of the bottom but....Still no luck.. Considering the hood was cracked open, the garage wasn't that hot and the car was sitting 18" in the air, this thing should have never gotten this hot.

Tomorrow, I am going to remove the intercooler all together, put the radiator cover on it, close the hood and idle it out in my hot driveway and see how hot it gets.. This is basically like back to a stock configuration with nothing in front of the condenser and an 8-10" gap to pull air up from the bottom from.

After that, I am going to try adding some timing to the idle table, right now its at 24* and my header temps are 800-880* after a 20 min idle, so maybe some additional timing will help.

I have to say, I was pretty heart broken with the temps after the fan install.... I love everything about the fan, other then the fact it didn't help any over the dual spals, and this wasn't even actually driving it and getting it heat soaked with the hood shut.

The quest continues...

Blackonblacksls

cmiller8006

Not sure if people use like a water wetter or not on cars, but I used it on my bike and ran consistent 10 degrees cooler with just the amsoil one

ajrothm

OK, let me update this mess for anyone that is bored enough to be following along...

Day 2 test with the 17" brushless fan was to remove the intercooler all together and drive it.

Huge gap... Measured 8" in the closest point... Much better then my usual 2" gap.






The fan came on around 174*, I ran it around the neighborhood a bunch of times, stopping and starting. Within 20 mins, it was at 230*.... It sat at 232* for about 7-8 mins so I thought maybe I had found the plateau. So I took it out on the road, getting up to 40-50 mph and it never really cooled down..I suspect this was due to the blower discharge dumping metric tons of air flow right in front of the radiator when the rpms are at 2k. I go to a gas station, gas up and start out home, temps sore.... Turns out the fan is not on.. Once again, the fan does not restart after its been shut off.. I limp it home and cool it down with the water hose. I come back to it a few hours later...

Its cooled down, I fire it up and the fan is on, so I go back to idling, the temp continues to creep... I saw 238* and normally, I shut off the ac but this time I wanted to see how high it would go... Finally once it hit 245*, I cooled it down with a water hose across the core and called it a day.

So today I wire up the override switch, I figure I'll just override the temp switch and make the fan run all the time as it will be running most of the time anyway. I put the intercooler back on and put everything back to normal. Fan is on, override is working I run it for 10 mins in the garage, hit 220* so I figured I'd test drive it. I shut it off long enough for me to go grab my wallet and a drink, come back out, fire it up and take off... Before I get to the end of my neighborhood, its at 245* and climbing fast. AC shut off, I turn around and haul *** home, you guessed it, fan is not on. Even with the override switch on, the damn fan is not on.. Its 250* by the time I can get the water hose on the core to cool it off.

At this point, I am so freakin pissed off I can't even see straight. I call John at Dewitts and we discuss everything, he recommend going back to the duals while we figure out the issue with the fan/harness. So I do just that.

While I was in there, I sealed up the core to the frame:





I get the duals back on, fire it up, lay under the car to compare the drafts and there was no contest, they were CONSIDERABLY stronger the 17" brushless.... They actually had some pressure across the floor.
SO I decide to try my suction test with the same piece of paper in the same locations that I did with the 17" brushless...

No comparison...

17" brushless:




Dual 12"


It literally pulled the paper out of my hand from the license plate hole


No doubt on my car, the 12" duals pull a lot more air then the 17" brushless. I call John at Dewitts and discuss everything, we pretty much determined that the 12" duals are probably the best flowing for my car, only bettered by the 12" dual brushless, which there is no way I can fit in there with the blower.

I am sending the 17" brushless back to dewitts for testing, they are going to troubleshoot it and see why it operates the way it does, why it never stays running after the car is off etc etc.. John was absolutely great to deal with and had no issue giving me back a credit... I just can't recommend those guys enough...(besides the fact I currently own 4 of their radiators).

Moving forward,
I made a new support brace that would allow me to "roll" the bumper cover up higher into the bumper area to open up some more gap to the IC..




Tomorrow I am going to road test the car, hopefully I haven't hurt it by it hitting 240-250 twice while screwing with the other fan.

My next test will be to remove the intercooler again and run it with the duals and see if it cools it down more at idle, if it does, I'll be relocating the IC to the license plate area.... Doing this test with the 17" brushless showed no improvement, but judging how much more air flow the duals have, maybe it will pay off... We'll see.

I know I'm tired of FKN with this thing though.