ykp53

I just recived a 16" perma cool fan to help keep my big block cool in stop and go traffic, but I was wondering since I will probely need to keep the stock fan also to keep it cool. Should I leave the shroud or remove it since I figured the electric will do the majority of the cooling now and the flex fan will act as a secondary fan. So does the shroud need to stay or go?

KenSny

If you are going to keep the stock water pump driven fan you WILL need the shroud. The fan will not draw air thru the radiator without the shroud channeling the air flow caused by the blades. HOWEVER why do you think you will need to keep it? Why add the electric if you are keeping the stock fan? Other guys here are running BB and not keeping both fan systems. Maybe you have other cooling problems associated with the radiator.

tshort

:iagree:

A cooling system in good order should have no problems with a flex fan and shroud. Or you can REPLACE, not add, some electric fans. I'm not sure if a single electric would do the job but dual puller fans will definitley get the job done.

ykp53

When i bought the car 3 years ago it had a flex fan w/ a mr gastket electric fan installed as secondary fan. this combo worked great i never saw temps above 200. while at the drag strip i had contact between the electric fan and the flex fan (thats why bubba should not use zip ties to hold the electric fan to the radiator) neither fan survied so i bought some pep boys aluminum fan and installed it it works fine on the highway or normal driving but when it get 90+ and i sit in a drive through or get cought in traffic the temp will get to 230+ also when i turn the a/c on forget staying below 240. So i purchased a nice single electric to suplement my flex fan. i know that one single electric fan is not enough to cool a big block on its own, but just because my car hits 230+ while sitting sitting in trafficwith the a/c on doesnt mean my cooling system is bad.

KenSny

One thing to remember is that GM used 5 and 7 blade fans that also had a different pitch to them. The 7 blade was used in AC cars. So it's possible your Pep-Boys fan was not the correct replacement since you had problems with the AC on.

I personally don't like the flex blade fans. I'd install the correct replacement.

markdtn

:iagree: Keep the shroud if you keep the original fan. A BB can be cooled with just electric C4 fans. See http://www.idavette.net/hib/bbfh7.htm

ykp53

I agree the el cheapo 5 blade aluminum fan might be part of the problem. i orignaly had a 7 blade black plastic. i get the impression that i shouldnt be running a stock fan w/ a secondary electric fan. my train of thought that my current set up works fine when moving but at a stand still i need to have more airflow through the radiator, so im adding a electric fan. is the electric fan going to block air flow? didnt the 80+ models come with both a electric and mechanical setup?

verskel

7-bladed Flex-fan with shroud on an L-89 radiator (27 1/2").......no problems overheating. :thumbs:

Fan >> http://store.summitracing.com/partde...art=FLX%2D1817


[Modified by verskel, 11:35 AM 4/26/2004]

The Money Pit

I run without and found it works quite well with the aluminum radiator.