Belly radiator -- Scoop or no-scoop?

markd89 · 2011-05-25T14:54:44+00:00

Hi, I'm working on a conversion of a 1Z TDI engine into a 78 Bus. I live in Los Angeles which has a relatively hot climate. I'd like to be able to drive in 100*F heat without overheating. I have an aluminum radiator with a core that's 13"x27" with dual 12" fans. Ideally, I'd like to mount it without a scoop so I retain ground clearance, easier maintenance, less fabrication. I realize that most here like Subaru's. The difference with the TDI is that it throws of less waste heat. I know that I can mount dual radiators without a scoop and be fine. I know that I can run a scoop with the one radiator and be fine. The question is whether I can run the one aluminum radiator without a scoop and be OK? I'd appreciate any opinions. Thanks! Mark

ElusiveStranger Officially Full-On Dubber

330 posts · joined May 2006 · 13 Aug 2011, 2:56 am

#856757

Sorry Pete, I should have phrased it better. My inlet's the width of the chassis rails and sits 4" lower than the rail
I have mentioned before that the outgoing air has more volume than the incoming & also that the rad needs at least 1/3 of it's surface area to really work.

Due to mine being situated in turbulent airflow and the fact it was going to be:

1/ Easier to fabricate
2/ Almost the same cost in metal

To make it nice and large
The result being the fan only comes on in very slow (or stationary) traffic. I'd wager money on the fan not kicking in on next week's 255 mile drive - except for traffic jams

ian.mezz I never said, I could write or spell

3,913 posts · joined Sep 2004 · 13 Aug 2011, 2:21 pm

#856803

I think those radiators look to big and the water flow is all out of whack. They mainly use cross-flow radiators in cars with a lack of room,
I d say you need to go talk to a radiator shop/ Guy to under stand
how a cooling system works.😊
YoU have the water going down then up then going into middle hoses bleeder and U tube
Then down then up again and back to the motor.
????

😂🤪😂🤪😂
car forums. where a lot of peoples good intentions end up taking a good old car off the road forever never ever to see the road again. 🥲

pete wood 23 Windows of Awesome

6,828 posts · joined Jan 2004 · 15 Aug 2011, 8:59 am

#857184

ian.mezz wrote:I d say you need to go talk to a radiator shop/ Guy to under stand how a cooling system works.😊

this is an awesome bit of advise and something I did. 👍

"stoopid is stronger than axles"
http://drivingnotpolishing.blogspot.com.au/

dlrecord Learner Dubber

19 posts · joined Sep 2010 · 19 Aug 2011, 1:01 am

#857860

Posting with some real world data on my setup after +/- 1,000 miles on the system:

'79 Bay Campmobile Delux Westfalia
stock auto 3 speed
2001 Subaru 2.2l n/a
aftermarket 210*f thermo switch to control fans (not ecu)
dual 14" pusher fans
1.5" rake front to back (front lower)
No boxing of sides or rear
No scoop

Fans kick on at about 207*F (thermo switch is a 210*F) and kick off at 195*. So far no overheating issues or other coolant issues. The fans are on a little more then I would like. I am thinking about buying some pool noodles to box in the sides and rear temperarily to see if that makes a difference or not.

I'll also be adding front and rear heaters this fall so we'll see how that impacts the system if at all. One thing at a time though so I can determine specific impact based on specific changes.

1979 Westfalia Campmobile Deluxe
2.0L EFI, 090 auto transmission

-----------------------------------------
Subaru 2.2L conversion project
http://1979vwconversion.blogspot.com/2010/09/start.html

markd89 Learner Dubber

8 posts · joined Jan 2011 · 19 Aug 2011, 1:40 am

#857861

Thanks for all the ideas and feedback 🙂

GeorgeL Officially Full-On Dubber

231 posts · joined Feb 2006 · 18 Oct 2011, 8:22 am

#867507

dlrecord wrote:Posting with some real world data on my setup after +/- 1,000 miles on the system:

'79 Bay Campmobile Delux Westfalia
stock auto 3 speed
2001 Subaru 2.2l n/a
aftermarket 210*f thermo switch to control fans (not ecu)
dual 14" pusher fans
1.5" rake front to back (front lower)
No boxing of sides or rear
No scoop

Fans kick on at about 207*F (thermo switch is a 210*F) and kick off at 195*. So far no overheating issues or other coolant issues. The fans are on a little more then I would like. I am thinking about buying some pool noodles to box in the sides and rear temperarily to see if that makes a difference or not.

I'll also be adding front and rear heaters this fall so we'll see how that impacts the system if at all. One thing at a time though so I can determine specific impact based on specific changes.

Nice to see some real data.

Boxing it in is a definite plus as it reduces recirculation when at a standstill. It also, when combined with a scoop, allows cruising without the thermo fan coming on. If your thermo fans are coming on at cruise speeds they are being worked too much, and the failure of a fan will result in rapid overheating on the highway.

An earlier poster mentioned a fighter aircraft being made faster through its radiator system. This is true, as he heated air expanded and was ejected from the rear faster which resulted in a bit of thrust. I wouldn't expect to do as well with a belly radiator operated in ground effect! 🙂

JVLRacing Custom Title Time!

1,100 posts · joined Mar 2007 · 20 Oct 2011, 8:53 am

#867817

Theres one way and one way only....

Rad up front full stop!! keep it simple! and bigger rads aint better its all about flow of air, cooling of water

General_Failure Use your head, don't abuse it!

1,036 posts · joined Jun 2004 · 1 Nov 2011, 4:05 pm

#869825

I "noodled" my cooling system recently . I intend it to be semi permanent. Sure they jam in there pretty tight but I have the feeling they'll blow out at speed. I can't really see them doing much for hot/cold air separation with the gap that are still needed to be filled behind my radiator but it should be interesting once I get around to making the plate for there. Only thing is I'll only be pulling the rad one more time so I'll be hopefully finding a way to cram the second cooling fan in there totally skewing results anyway.

With the big rad and small motor it seems to do pretty well with only one thermo fan and no proper hot / cold separation but putting it to work on the open road is probably a different matter entirely.

If at first you don't succeed. Build, build again.
Vehicle: 1975 Special order delivery walkthrough panel based LCA pop-top camper. Motor: Nippon 1.8L Single port Wasserboxer, Transmission: 3 rib 002.