[sandiegopaul]

Car is a '76 Corvette with a 383, mild at 350HP. OEM fan and shroud gave no problems, using new radiator with a 'high-efficiency core.' Even with A/C on, it only ran 195-200*

But when I rebuilt the front suspension last week, I pulled the big bulky shroud off, along with the fan and clutch. I then purhcased a 16" Zirgo rated at 3650 CFM which I figured would cool me nicley. It does, but for when I'm in traffic. The fan runs fine, but temp runs 210-220 because there's no shroud.

Who can give me tips on building a home made shroud? I haven't a clue but I know I need one. I'm afraid to run the A/C now because I know that if it isn't keeping things cool now, it's not going to draw enough air thru the condensor either.

Knowing what an aluminum fan costs, and knowing that I already have plenty of CFM thru the fan, the shroud is the logical solution.

Thanks for any help.

[Rob Keller]

the shroud is a important piece but so is the factory fan and clutch the clutch is a critical piece especially down here
im not familiar with vetts so there prob is not room for both
what temp on the stat?
so talk to Docvette and or go back factory lower the stat temp i rn 160*s down here in Fla

sr66

[dreamcatcher]

I will just want to add that I have a 76 vette and the shroud got broken on the very bottom there is about a 10 inch piece missing.After this happened I have had cooling problems.The shrouds are very important to the design on the vette.Air flow gets disrupted.Mine even over heats with just part of the shroud gone.The cooling design requires the shroud to complete the air flow pattern.I wanted to do the same thing you did but it dont sound like a good idea at this point.

[sandiegopaul]

Originally Posted by Rob Keller

the shroud is a important piece but so is the factory fan and clutch the clutch is a critical piece especially down here
im not familiar with vetts so there prob is not room for both
what temp on the stat?
so talk to Docvette and or go back factory lower the stat temp i rn 160*s down here in Fla

sr66

Can't go back to factory - two reasons: I pulled the shroud off PURPOSELY because it blocks too much of the acessiblity to front of the engine. Secondly, the only way to get it off properly was to pull the radiator. So I used the dremel tool and cut it into pieces small enuf to remove it piece by piece.

I also really like the engine compartment now that the big ol' hunkin' 70's shroud is off the car. Much neater.

If somebody can help me assemble a tin shroud that's only a couple inches deep, I'll be happy as a cat coverin' chit!!

Lowering thermostat temp won't help you cool a motor that has already warmed up past it's opening temperature, btw. It will only get the radiator hot faster.

[Triaged]

I think the shroud is only a small part of your problem. The fan you bought doesn't pull enough CFM's. A good fan to use is from the old Taurus' with the big V6. It is a 2 speed fan that pulls 5000 CFM on high. I am sure that your old clutch fan was rated at well over 5000 CFM. The Taurus fan comes with a shroud and can be had in the j/y for cheep (about $30). I don't think you would want a new one as they are more like $400 You could sell your current fan on ebay and it would be a wash in cost and have better cooling.

Just look at it this way...
If that stupid Taurus V6 (that put out what 175 hp?) needed a 5000 CFM fan how many CFM's does your vette need!

Edit:
Looks like the Taurus fans put out more like 4000-4500CFM
They draw over 40A while on (more at start up) so you need to get a good relay or run 2 of the standard 30A relays to run one. They also come with a shoud on them.

[sandiegopaul]

Originally Posted by Triaged

Just look at it this way...
If that stupid Taurus V6 (that put out what 175 hp?) needed a 5000 CFM fan how many CFM's does your vette need!

Edit:
Looks like the Taurus fans put out more like 4000-4500CFM
They draw over 40A while on (more at start up) so you need to get a good relay or run 2 of the standard 30A relays to run one. They also come with a shoud on them.

Interesting. Thanks for the info, but it seems to contradict what I've read about fan ratings/requirements. Others seem to be using 3,000 CFM fans just fine on V8's .... Any other takers on this one?

[Triaged]

Originally Posted by sandiegopaul

Interesting. Thanks for the info, but it seems to contradict what I've read about fan ratings/requirements. Others seem to be using 3,000 CFM fans just fine on V8's .... Any other takers on this one?

My opinion isn't popular but I feel it to be more in line with reality.

-Many people don't have to worry about desert driving in stop and go traffic like we do in SoCal.
-Electric fans almost always flow less than the factory clutch fan
-Many people don't have AC on their hot rods.
-If you look on the side of the box you will note that many of the fan manufactures don't recommend using their electric fans for primary cooling on V8's.
-It wasn't till recently that GM even thought about putting a electric fan on a truck.
-From what I have seen factory fans (large V6-V8) almost always outflow even the highest flowing aftermarket fans. I think they did their homework.

[sandiegopaul]

Originally Posted by Triaged

My opinion isn't popular but I feel it to be more in line with reality.

-Many people don't have to worry about desert driving in stop and go traffic like we do in SoCal.
-Electric fans almost always flow less than the factory clutch fan
-Many people don't have AC on their hot rods.
-If you look on the side of the box you will note that many of the fan manufactures don't recommend using their electric fans for primary cooling on V8's.
-It wasn't till recently that GM even thought about putting a electric fan on a truck.
-From what I have seen factory fans (large V6-V8) almost always outflow even the highest flowing aftermarket fans. I think they did their homework.

Thank you! Each and every point is very well taken too.

[camaroman7d]

I know for a fact there is an electric fan out there that will cool your Vette with no problem. It is not cheap but, it works. It kept my 388ci blown small block cool even in temps over 100*. It also worked perfect in stop and go traffic on 100*+ days. It is made by Vintage Air, check out their site. This fan is large and you do not even need a shroud. It is the most powerful electric fan on the market. It flat out moves air.

I disagree that electric fans are not meant as a primary cooling fan. Those companies are trying to cover their butt. There are millions of cars that only have electric fans (from the factory as well). Companies always put those diclaimers on parts ie.. Wilwood brakes "for racing use only" Weld rims (certain models/sizes) "not meant for street use".

If you need the part number for the Vintage Air fan let me know and I will look through my reciepts and see if I can find it.

My buddy has one on his 383 powered 69 Corvette, he couldn't keep it cool until he put this fan on.

Royce

[sandiegopaul]

Hey Royce, thanks! Is that fan naked or shrouded?
part number?

[camaroman7d]

I just went through I reciepts and I couldn't find it. I have a stack several inches thick and I am sure I overlooked it. Here is a link to the fan http://www.macsradiator.com/browsepr...nster-Fan.html

The an is 18" in diameter. I ran mine without a shroud as does my buddy with the Vette. If I find the part number I will post it here. They do make a shroud for it as well, shown in the picture. I will also try to find a picture of mine installed so you can get an idea.

Royce

[camaroman7d]

I have a picture of the fan installed on my car but, the file is too big to upload here. If you would like it I can e-mail it to you. Just let me know.

Royce

[circletrack62]

if your you want to stick with a mechanical fan try a four blade fan. we use them alot in dirt track racing because they draw alot of air.

[bet on black]

i have an efan off of a newer 4.6L mustang (motorcraft part # rf-86) on my 2003 ford lightning. it has 400 hp/ 500 ft. lb. of torque, a/c and is daily driven in houston, i even tow with it. no problems overheating here, but it is in a shroud. the fan costs about $130 new, but you need something to control it.
it is a good fan with two speeds. i have set it so it runs on low for regular cooling, high speed if the coolant temps start to rise above 200*F. it has never gone on high speed for more than 5 seconds.

[69er]

I live near palm springs, ca and it is hotter than hell. After years of mech/elec fan experimenting on my 69 bb corvette, I finally bought a DeWitt aluminum radiator with 2 fans installed on it ready to go. I think that the old copper radiator was just too thick for good air flow no matter what you do. I have been really happy with this combo. The new fans are shrouded/they're Spals. I've got the old shroud for the single mechanical fan, but it's not aluminum- it's tough thick black plastic. The radiator sits at an angle too,
so air flow is not easy to create. I tried every conceivable combo: electric/ mechanical and both over the years, and this finally did the trick. I've got the old shroud, the original radiator (I even had extra copper tubing put in it years ago), a couple of electric fans. hoses up the gazoo and all kinds of 69 Corvette big block goodies. It's amazing what I've collected over time.