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Steve1968LS2
03-26-2006, 05:45 PM
Received my radiator and electric water pump yesterday.. that means my cooling system is complete.. :woot:

chicane67
03-26-2006, 06:04 PM
Wow. It would be nice if 35-40% of the RAD wasnt covered. The fan is only needed when at low speeds and/or standing still. The shroud then becomes a restriction from a relevent aero speed, which on our chassis is around 27mph.

Steve1968LS2
03-26-2006, 06:19 PM
Wow. It would be nice if 35-40% of the RAD wasnt covered. The fan is only needed when at low speeds and/or standing still. The shroud then becomes a restriction from a relevent aero speed, which on our chassis is around 27mph.

So you would have an issue with this design as well:

https://static1.pt-content.com/images/pt/2006/03/1A22193T120ALUMINUM20RADIATOR-1.jpg

I would have to measure to see how much of the radiator is covered.. which is relative since none of it is really covered (ie, blocked. When the fan isn't spining and your driving at speed I would think enough air would pass through the fan opening to cool the car. Also, if there is a "bit" of back pressue that shouldn't be an issue so long as enough air is moving past through the radiator.

I guess my point is "so what" if the shroud is a bit of a restriction so long as a suficcient volume of air is moving through the radiator. :)

TUBED
03-26-2006, 08:58 PM
Looks nice, how many CFM does the fan pull?
Gerald

chicane67
03-26-2006, 09:06 PM
Well, if one were to take into consideration of the creation of negative pressure behind the core support...... then no, it wouldnt be too much of a problem.


Also, if there is a "bit" of back pressue that shouldn't be an issue so long as enough air is moving past through the radiator.

I guess my point is "so what" if the shroud is a bit of a restriction so long as a suficcient volume of air is moving through the radiator.

The problems with cooling are mainly at low vehicle speeds, which should be considered for street driving. Any restriction beyond the natural core flow resistance can impeade on the systems performance. Unless....... you have introduced something to combat the pressure difference needed to improve air flow thru the core itself. A good example is any late model. There isnt much of an opening in the front body and their implimentation of air dams under the core support and venting the underhood pressures via side exhaust ducting (like that on the C5/6) does wonders for drawing air thru the core. Without this help, they would cook.

Air flow exposure to the total core area is the key.


.......as long as a suficcient volume of air is moving through the radiator.

For a street chassis, I might agree with this. But, not for a chassis that is going to see any track time. And we know Penny isnt going to be just a street queen.... right ??

Steve1968LS2
03-26-2006, 09:42 PM
I don't think there will be a problem. Given that the engine I am running is all aluminum and sheds heat well (besides the fact that LS1 enjoy a higher temp than say a traditional SBC). The fan is ran off a temp sensor inthe radiator so if the temp goes up to far the fan will come on and pull more air through, regarless of the speed of the vehicle.

Also, I will get a small gain in air flow from the DSE Closeout (more air forced through the radiator rather than up).

AFCO is not (by far) the only performance radiator company to use shrouds of this type.. If if turns out to be a problem at the track I will come up with another idea. The other benefit is that my water pump is consistent and any speed since it's electric.

LowBuckX
03-26-2006, 11:24 PM
In Laymans terms Your fan when running withPenny at say 35 mph or faster will act as a solid object blocking air from passing through your core.
Look at spals set up it contains "blow off" doors that pop open when the pressure in front of the fans exceeds the pressure behind the fan.https://static1.pt-content.com/images/noimg.gif

LowBuckX
03-26-2006, 11:39 PM
BTW I cant see thumbnails for some reason so I cant see your first pick just the second one

rocketrod
03-27-2006, 05:20 AM
In Laymans terms Your fan when running withPenny at say 35 mph or faster will act as a solid object blocking air from passing through your core.
Look at spals set up it contains "blow off" doors that pop open when the pressure in front of the fans exceeds the pressure behind the fan.https://static1.pt-content.com/images/noimg.gif
I was wondering if someone was going to make this point,which is important.

Steve1968LS2
03-27-2006, 07:08 AM
In Laymans terms Your fan when running withPenny at say 35 mph or faster will act as a solid object blocking air from passing through your core.
Look at spals set up it contains "blow off" doors that pop open when the pressure in front of the fans exceeds the pressure behind the fan.

I think you diagram makes it look a "bit" worse than it really is since you show ZERO air going through the fan opening. Also, if this occured and the temp climed wouldn't the fan then kick on and pull the air through the area?

Also, wouldn't this mean that most radiator mfgs (including Ron Davis, AFCO and others) know less about radiator design than you do ;) lol

Actually I guess that would be "less about shroud design".. Are you saying that I should add rubber "blowout" flaps like on the plastic SPAL fan deal?

I will call a couple radiator guys I know and pick thier brains on this. Might be a good excuse for a story on cooling theory.. could call it "keeping your cool". Can I use your artwork? :D

Rick Dorion
03-27-2006, 07:49 AM
I'd be interested in what you find out, Steve. I am about to send my Griffin radiator to them to have a shrould made and attached.

harshman
03-27-2006, 08:42 AM
If my memory serves me correctly, shrouds are required for mechanical fans only and can be considered restrictive otherwise. This is not my opinion but that of many a racer. Fans are only for low speed air flow and are not required above 35 mph. Yes a idle fan is restrictive – just put your hand out the window doing 50 mph and you'll get an idea, however I think we are approaching more cooling theory than general purpose as which I think penny will most likely see (track and street). Ideally a radiator will work most effectively when unrestricted airflow touches all the fins.


All this to say that you will be fine.:jump:

chicane67
03-27-2006, 08:47 AM
Also, wouldn't this mean that most radiator mfgs (including Ron Davis, AFCO and others) know less about radiator design than you do ;) lol

Actually I guess that would be "less about shroud design".. Are you saying that I should add rubber "blowout" flaps like on the plastic SPAL fan deal?

I will call a couple radiator guys I know and pick thier brains on this. Might be a good excuse for a story on cooling theory.. could call it "keeping your cool". Can I use your artwork? :D

Now that's funny. I also concur with the "pressure flaps". Call it useful insurance.....

If you end up doing an article on this, be sure and contact Chet at C&R besides the previously mentioned guru's.

Allow me to include a statement of a system that beats the shroud theroy. It was a system I worked up with one of our own:


I'd suggest using the in-tank cooler design. If for no other reason, it makes packaging significantly easier than an inline type.

If you are planning on spending some quality time on a road coarse a cooler will make your time at the track much more enjoyable.

My C&R dual is in the $450-500 range. It a pretty serious piece. Add on $100 for brackets and welding, $150 for a Mark VIII fan, and $125 for a DC conroller. In August at Buttonwillow, with ambient temps of 104*, it never broke 185*. Asthetically it's not 100%, but functionally it's hard to beat.

You may also want to consider an oil temperature thermostat. CV has a really nice one. Check the archives for some great discussion on this topic.

And I believe Andrew's comment, sum's it up nicely.

No matter what Steve, your approach to the build of Penny is uber bad @ss.

Steve1968LS2
03-27-2006, 08:55 AM
If my memory serves me correctly, shrouds are required for mechanical fans only and can be considered restrictive otherwise. This is not my opinion but that of many a racer. Fans are only for low speed air flow and are not required above 35 mph. Yes a idle fan is restrictive – just put your hand out the window doing 50 mph and you'll get an idea, however I think we are approaching more cooling theory than general purpose as which I think penny will most likely see (track and street). Ideally a radiator will work most effectively when unrestricted airflow touches all the fins.


All this to say that you will be fine.:jump:

True but wouldn't the fan blades (when the fan is off) be less of a restriction since they move/spin (unlike your hand out the window.)

Remember, Penny is NOT a race car.. she is a street car that will hit open track days and hopefully a few open road deals.

In any event it's a good discussion :)

Steve1968LS2
03-27-2006, 08:57 AM
Oh, will the fact that I am running an oil cooler take some pressure off the coolant system? I would think so since cooler oil would equal a cooler engine and thus cooler coolant..

harshman
03-27-2006, 09:34 AM
you forgot about the motor.

CarlC
03-27-2006, 06:43 PM
My 2cents....

Spal's not the only one to use flappers. Check out the 4th-gen V8 cars. They have the flaps. GM would not put them there unless there was a reason.

And another one of those reasons? Reliabilty. If the car has to rely on the fan to keep it cool at constant-street and freeway speeds it will lead to significantly reduced fan and alternator life. A few rubber panels are a lot cheaper than replacing expensive electrical components.

Mine has a LOT of cooling capacity.

Steve1968LS2
03-27-2006, 06:49 PM
My 2cents....

Spal's not the only one to use flappers. Check out the 4th-gen V8 cars. They have the flaps. GM would not put them there unless there was a reason.

And another one of those reasons? Reliabilty. If the car has to rely on the fan to keep it cool at constant-street and freeway speeds it will lead to significantly reduced fan and alternator life. A few rubber panels are a lot cheaper than replacing expensive electrical components.

Mine has a LOT of cooling capacity.

So the $100k question would be how could one install "flappers" onto an aluminum shroud.. hmmm

Ideas?

harshman
03-27-2006, 07:01 PM
Scissors :2nd:

Steve1968LS2
03-27-2006, 09:02 PM
Scissors :2nd:


:getout:


lol

Matt@RFR
03-27-2006, 09:15 PM
A jigsaw, some rubber and some rivets.

chicane67
03-27-2006, 09:42 PM
So the $100k question would be how could one install "flappers" onto an aluminum shroud.. hmmm

Ideas?

How good do you want it to look ??

Im up for Matt's idea....... A drill, tin snips, some scrap aluminum strips, rubber for the flaps and a few rivets.

Or... a plasma cutter, some plastic or aluminum strips, rubber and a few rivets.

Id take a closer look at a factory unit and then let your imagination run with it.

Matt@RFR
03-27-2006, 10:49 PM
'Course, if we were talking about the "perfect" system (with regard to available technology), the radiator would be leaned forward and sealed to an opening in the grille and below the air damn/splitter. And on the engine side of the radiator, it'd be sealed to outlets in the hood. No air can double back through the radiator, and it wouldn't fill the engine compartment with pressurized and hot air.

I think that's what you should do Steve. :)

Tom, I understand that the fan(s) would hinder airflow at high speed if the blades were not turning, but what if the blades turned with the air going past them, even if the fan motor wasn't running? Do they do that when sealed to the radiator with a shroud like Steves? If they do, what's your guess as to what MPH the fan would reach terminal velocity? I'm sure it's highly dependant on specifics, but what's your general feeling on this?

Steve1968LS2
03-28-2006, 08:28 AM
'Course, if we were talking about the "perfect" system (with regard to available technology), the radiator would be leaned forward and sealed to an opening in the grille and below the air damn/splitter. And on the engine side of the radiator, it'd be sealed to outlets in the hood. No air can double back through the radiator, and it wouldn't fill the engine compartment with pressurized and hot air.

I think that's what you should do Steve. :)

Tom, I understand that the fan(s) would hinder airflow at high speed if the blades were not turning, but what if the blades turned with the air going past them, even if the fan motor wasn't running? Do they do that when sealed to the radiator with a shroud like Steves? If they do, what's your guess as to what MPH the fan would reach terminal velocity? I'm sure it's highly dependant on specifics, but what's your general feeling on this?

Gee Matt.. why does that idea sound familiar??? lol

As for the second part.. the blades do "freewheel" when the motor is not on and the wind is just cruising past. I think the obstruction they were speaking of is the Motor itself.

Ok.. lets say the fan can move 2000 CFM of air when on.. That would mean that the open area can accomodate that much air. So if your car was going fast enough would the be forced through? After all, doesn't the air want to find the path of least resistance?

The whole concept would be easy to test.. I've used devices that measure airflow (for testing HEPA filter air flow).. I'm sure they could be used to measure airflow through the fan opening when the fan is off and at various speeds of forward movement. I guess that would answer things once and for all..

Matt@RFR
03-28-2006, 09:12 AM
The whole concept would be easy to test.. I've used devices that measure airflow (for testing HEPA filter air flow).. I'm sure they could be used to measure airflow through the fan opening when the fan is off and at various speeds of forward movement. I guess that would answer things once and for all..

Do eeeet.https://static1.pt-content.com/images/noimg.gif

chicane67
03-29-2006, 08:50 PM
Dont forget to cup the ball's.....

Richz68
03-31-2006, 09:32 PM
So the $100k question would be how could one install "flappers" onto an aluminum shroud.. hmmm

Ideas?

Steve,

This is a technical topic of discussion from time to time and we can only go off of the hundreds of aluminum shrouds on our customers rides that are just fine.

It really seems to be more of a concern with the more technical-based crowd like us here at PT. Don't get me wrong here guys I am guilty of over analyzing things too, but our all of your customers rides without the flaps do just fine at any speeds.

We have however decided to accomodate the customers who ask for the flaps on thier custom aluminum shrouds rather than turn them away. We are now installing the rubber flaps on the aluminum shrouds at an extra charge.

You can easily install the 3-1/4" x 1-7/8" flaps by drilling two 1-1/4" diameter air holes about 3/8" apart using a hole saw & drill. Then you will need to drill three 7/64" holes for the rubber anchors to slide through along the TOP of the air holes. Push the rubber anchors through and your done..... no worries and your mind will be set at ease. The toughest part is to locate the flaps!


https://static1.pt-content.com/images/noimg.gif

Steve1968LS2
04-01-2006, 07:11 PM
Steve,

This is a technical topic of discussion from time to time and we can only go off of the hundreds of aluminum shrouds on our customers rides that are just fine.

It really seems to be more of a concern with the more technical-based crowd like us here at PT. Don't get me wrong here guys I am guilty of over analyzing things too, but our all of your customers rides without the flaps do just fine at any speeds.

We have however decided to accomodate the customers who ask for the flaps on thier custom aluminum shrouds rather than turn them away. We are now installing the rubber flaps on the aluminum shrouds at an extra charge.

You can easily install the 3-1/4" x 1-7/8" flaps by drilling two 1-1/4" diameter air holes about 3/8" apart using a hole saw & drill. Then you will need to drill three 7/64" holes for the rubber anchors to slide through along the TOP of the air holes. Push the rubber anchors through and your done..... no worries and your mind will be set at ease. The toughest part is to locate the flaps!


https://static1.pt-content.com/images/noimg.gif

I could just buy them from you.. right?? lol

I'm really not worried about it, but if an issue arises I will start flapping..

Richz68
04-01-2006, 07:50 PM
I could just buy them from you.. right?? lol

I'm really not worried about it, but if an issue arises I will start flapping..


Nah.... I'd send you four of them....... you supply the labor. I really don;t think you will need them though. Is that an AFCO radiator?

FJB2069
10-18-2006, 10:14 AM
Steve,

It appears you are using an independent fan controller and I was curious as to why you weren't going to let the ecm control it?

Steve1968LS2
10-18-2006, 01:01 PM
Steve,

It appears you are using an independent fan controller and I was curious as to why you weren't going to let the ecm control it?

It's never a good idea to let the ECU do it. I heard it can begin jerking around with when the fans come on and off. I'm a bit foggy on this since it was explained to me several years ago.

Mainly there is no good reason to let the ECU do it. It's much more accurate to put a probe in the radiator and use a relay. The relay I have from AFCO is adjustable so I can easily change when the fan comes on without hooking up a laptop and changing the ECU.

On my '69 I had two probes, one for each fan on my SPAL deal. Worked great.

Oh, and the ECU gets its water temp from the engine (forward area of the drivers side head). Getting your water temp from the input side of the radiator is a better location.

camcojb
10-18-2006, 01:07 PM
It's never a good idea to let the ECU do it. I heard it can begin jerking around with when the fans come on and off. I'm a bit foggy on this since it was explained to me several years ago.

Mainly there is no good reason to let the ECU do it. It's much more accurate to put a probe in the radiator and use a relay. The relay I have from AFCO is adjustable so I can easily change when the fan comes on without hooking up a laptop and changing the ECU.

On my '69 I had two probes, one for each fan on my SPAL deal. Worked great.

Oh, and the ECU gets its water temp from the engine (forward area of the drivers side head). Getting your water temp from the input side of the radiator is a better location.

Never heard of that. With the aftermarket ECU's they use the ground for the relay, and I like it because I can tell it exactly when to turn on and off. The sensors that ground at a certain temp seem to always be quite a bit off.

As far as where the ECU gets it's temp from, that would depend on where you put the sender! It can go in the input side of the radiator if you wanted it to.

Jody

gmachinz
10-19-2006, 01:46 PM
If the ECM has the ability to use a pulse width modulation circuit to control fan speed, then that's the best option-ala Ford with their factory Mark VIII fans. Steve, I don't think you'll need flappers either. The shroud offers very little resistance if it's sealed to the radiator fins or side tanks because the entire area inside, even the area not directly open will act as a funnel which will actually aid in the velocity of the air going through which means the fan will have to work less at idle. Spal has a nice option of allowing for independant fan control or dual mode or electric fan with easy tuning changes. If anything, I wouldn't like the amount of ambient heat the aluminum shroud would absorb-acting as a sort of fryer. ABS plastic shrouds are my choice for that reason alone, which is why I still stick to OEM style fans/shrouds-plus nobody makes a better quality fan that the Mark VIII. But, I think you'll be fine with what you're running nontheless. -Jabin

70GS455
10-23-2006, 12:02 PM
Get some flappers from Home Depot - dryer vent flappers, they're spring loaded but should open with slight wind pressure.

justforfun
10-23-2006, 04:34 PM
As long as you have access to the settings in the ECU why would anyone consider not using the ECU to control the fans?
-Tables can turn the fans off above a certain speed. The fans can actually reduce the cooling effectiveness at speed.
-Built in speed control limits current draw. Earlier systems had 2 fans and would control them independently.
-net result is stable engine coolant temp

-TC placement is used to monitor engine coolant temp which affects almost every mode of operation, thus it is the parameter the ECU wants to control. As long as ECT is where desired there is no need to know the radiator water temp.

That being said, most people would never notice the performance differences between the systems. If you don't have ECU software or an adjustable relay just makes sense, the system will still work properly.

Alumitech Reproductions
10-24-2006, 11:15 PM
:cool: Well i just thought I would jump in to the thread
yes back bresure can be a problem when too much of the core is covered with a aluminum shroud ...at speed it can be like having that much card board in front of the rad ... the air has a hard time pushing trough the fan size hole
spal has the best design I have seen ...12 rubber pressure relief flaps for air passage at speed .
see this link
https://secure.wf-api.com/www.chevellecooling.com/46.html?psid=aMZiIDm.pcKk6nEX5M8d&sm=8856

as you will see the core is covered by the fan shroud aprox 400 sq inches .. but the air flows trough at speed .
Don

Steve1968LS2
10-25-2006, 06:31 AM
Never heard of that. With the aftermarket ECU's they use the ground for the relay, and I like it because I can tell it exactly when to turn on and off. The sensors that ground at a certain temp seem to always be quite a bit off.

As far as where the ECU gets it's temp from, that would depend on where you put the sender! It can go in the input side of the radiator if you wanted it to.

Jody

Hey, just what I was told by the guy that did the radiator on my '69.. :shrug: - Something like what I posted. It didn't really bother me so I went with his suggestion.

The AFCO relay has a dial so I can adjust when the fan comes on.

As for flaps.. we will see..

camcojb
10-25-2006, 07:33 AM
Hey, just what I was told by the guy that did the radiator on my '69.. :shrug: - Something like what I posted. It didn't really bother me so I went with his suggestion.

The AFCO relay has a dial so I can adjust when the fan comes on.

As for flaps.. we will see..

Certainly shouldn't be an issue Steve, as far as not using the computer. I just like to use all the features of these EFI systems!

Jody

MonzaRacer
10-29-2006, 10:36 AM
OK Steve just saw the article on the front clip instal very cool. ANYWAY, as a hot rodder, a Certified Master tech and a fella who has built pretty much every car I drive since getting out of school. first of all some people just OVER THINK it.
After several cooling exercises in my chosen project at the time (most notably was a 350 powered 86 short bed Ranger with FACTORY 2.0 4 cyl rad and it never got over 220 at its hotest:jawdrop: .
Now how did we do it, It had a solid/flex 7 bade fan on it as it was all had but the truck never tried to over heat even with that itty bitty rad. Now tell me your big bad high dollar rads wont provide coling for your car.
come on guys after owning a few Hbody Monza/Skyhawk trust me i know heat management.
first of all if you run your fan you are just loading the blades and fan motor too much and can seriously degrade the life of it.
I had a 3 core rad in my 70 Monte carlo with a high compression 402 and drove it for several years that way, as for the aftermarket fan and aluminum shroud , forget it I ran one and got my 71 very hot going into Nashville on the Power Tour (forget year, but Suzy Bogguss sang I even got a pic with her ,{hottie} ) so that siystem went out with the trash and I got an electric fan from a Grand Am and never had a problem again.
So here are some very wise words of advice from the front lines of car building and as an experienced cooling system tech (yes i get all the fun stuff at work and have never ahd a car fool me yet):
First:Mostly you need air flow through the core so super thick cores dont alwyas get it on street cars.
Second you dont need fans running at road speed anything over 25-30 mph is a waste of energy period and I have proven it on the street for YEAR.
Third: Use better coolant , you gut will blow $1000 bucks on super high dollar rads anf you have already got products on the market that would suffice, Try Evans Cooling NPG+ coolant. It boils at 369 deg F with no preasure. With a 15 pound cap you get something that wont boil till over 425 drgrees. Trust me it works a friend has a thin wall 283 bored to 4 in and it never over heats with NPG+ but it did with AF/Water.
Fourth: Why does eveyone make it so hard. Own an Hbody or a V8 Ranger with a 4cyl rad and then tell me it gets hot.
If you set up a thermostatic control and make it come on approx imately 15 degrees over your thermostat opening and shut of about the T-stat closing it should cool the car perfectlyand if it decides to come on while your driving so be it.
I see these guys making wild statements but never sem to fix problems with out zillion dollar products that a fella like me so far can afford nor condone.
to me hot rodders make it too complicated but never understand the basic dynamics of cooling, fuel , ignition, etc.
The KISS rule provides many good things and you guys seem to forget that.
Please dont over look basics and throw a credit card at it. Use some basics.
I have friend who had a 78 Monza, 400 sBC 060 over and never got it to cool even with big name custom built aluminum rad.
I am not saying the rad wont work nor does the bling factor hurt. But you keep busting your A$$ to fix something thats too easy.
for the most part everyone wants to keep cars super cool but in fact if you keep your car at or near 195-205 your engine works the fuel it burns much better (not talkin inlet temp ,,engine temp) with less unburned fuel thrown away.
I build race engines and hate to see guys try to run thier engine at 140 degrees at the line. I build engine to work best at around 180 lowest to 205 highest, ball park I shoot for 195/200 rangethen if you get to the line its just right when tsat opens.Thermally an engine with consistent temp makes most power on average.
Come on guys this debate just brings patches to light and while they work, why patch it just do what it takes to make it work more efficiently.
My choice would be a thermostatic fan ,only run it at speed if needed (rpm/speed sensative?) and use Evan NPG + ,a good cap and expansion tank and let her run. Bet it wont over heat especially with that huge rad and a good fan ,properly controled.
Sorry this was so long but I like to spread my information as best as I can and while I may be long winded writing I hope this adds to your possibilites for cooling.
Lee Abel
AFTERMARKET PERFORMANCE

Steve1968LS2
11-03-2006, 10:16 AM
Hey, Just back from SEMA

The AFCO double pass "two on the right" radiator I'm running will now be the STANDARD offering from AFCO and no longer a custom deal.

So, for what I posted earlier it's about $750 with the fan and shroud or four something for just the radiator. Full polishing is included in those prices (if you're into that sorta thing.. lol)

Just thought I would let you guys know.

Ron S
11-04-2006, 02:37 PM
A buddy of mine just got one for a 66 chevelle ls1 conversion,and I have to say,it is a very nice peice,I'm getting ready to order one for my Camaro

GetMore
02-27-2007, 03:30 PM
I did see somebody say that a shroud is not needed with an electric fan and I wanted to address that point. If you don't use a shroud (and this is the same reason those flaps are used) the air could circle from the back of the fan, through the radiator and back again, causing a reduction in cooling efficiency.

I definitely agree that proper ducting will make various improvements in the vehicle, from cooling to handling.