Hood vents?
Winching
Joined: Oct 2008
Posts: 579
Likes: 12
From: Auburn, AL
IMHO you are changing the air flow thru the radiator (change the cfms), not venting extra heat or removing radiant energy from the exhausts and block at such a rate that you are cooling things. Perhaps repeat your tests and add an IR thermometer measuring the temp of the block, manifolds, etc. You could also hole saw a series of opening in the firewall that would allow air to flow out through the cavity under the windscreen, and out the pollen filter array. If the holes don't work for you, they could be filled with knock out plugs or some fender washers and bolts.
Now I certainly think the Rover fan is smaller than it needs to be. You can increase cooling with a fan with deeper pitch blades. I saw 6 - 10F change with that. But my best result was going to a 180F stat. I now run 180 -183 at modest speeds and perhaps climb to 187 at 70 while I watch the gas gauge move. It is hot and humid where I live, frequently in high 90's or low triple digits. All my hood strips are in, as wells as radiator rubber strips. And for sound control I added the hood blanket from a D2, don't know if D1's came with or without them.
Another problem IMHO for D2's is that they only have a single AC condenser fan, and it does not run whenever AC is on, like the D1 does. If you modified the fan to be on when AC is on I bet temps we be lower at slow speeds.
Now I certainly think the Rover fan is smaller than it needs to be. You can increase cooling with a fan with deeper pitch blades. I saw 6 - 10F change with that. But my best result was going to a 180F stat. I now run 180 -183 at modest speeds and perhaps climb to 187 at 70 while I watch the gas gauge move. It is hot and humid where I live, frequently in high 90's or low triple digits. All my hood strips are in, as wells as radiator rubber strips. And for sound control I added the hood blanket from a D2, don't know if D1's came with or without them.
Another problem IMHO for D2's is that they only have a single AC condenser fan, and it does not run whenever AC is on, like the D1 does. If you modified the fan to be on when AC is on I bet temps we be lower at slow speeds.
Any ideas on how to do the condenser fan mod? Is there a relay or something I could remove to see what happens?
Super Moderator
Joined: Jan 2011
Posts: 16,322
Likes: 88
From: Savannah Georgia
Here's the test numbers for me (D1, 183K, hood blanket from D2, all rubber strips installed, 180F stat. Radiator rodded out within past year.
Start idle test - hood closed, off
8:15 IAT 84 ECT 77
8:23 IAT 88 ECT 142
8:39 IAT 131 ECT 180
8:49 IAT 145 ECT 183
9:07 IAT 160 ECT 189
Open hood all the way
9:09 IAT 156 ECT 187
9:17 IAT 142 ECT 180
9:19 IAT 138 ECT 180
Removed side rubber strip, hood closed back
9:39 IAT 160 ECT 189
Took off down the flat road for drive at 60 mph
9:55 IAT 120 ECT 180
Returned and instaled strip, repeat road test
10:23 IAT 118 ECT 180
AC on, back to 60 mph
10:26 IAT 124 ECT 180
10:34 IAT 126 ECT 183
Park and idle
10:44 IAT 160 ECT 196
open hood
10:47 IAT 157 ECT 196
11:08 IAT 145 ECT 194
Start idle test - hood closed, off
8:15 IAT 84 ECT 77
8:23 IAT 88 ECT 142
8:39 IAT 131 ECT 180
8:49 IAT 145 ECT 183
9:07 IAT 160 ECT 189
Open hood all the way
9:09 IAT 156 ECT 187
9:17 IAT 142 ECT 180
9:19 IAT 138 ECT 180
Removed side rubber strip, hood closed back
9:39 IAT 160 ECT 189
Took off down the flat road for drive at 60 mph
9:55 IAT 120 ECT 180
Returned and instaled strip, repeat road test
10:23 IAT 118 ECT 180
AC on, back to 60 mph
10:26 IAT 124 ECT 180
10:34 IAT 126 ECT 183
Park and idle
10:44 IAT 160 ECT 196
open hood
10:47 IAT 157 ECT 196
11:08 IAT 145 ECT 194
Administrator
Joined: Apr 2006
Posts: 25,707
Likes: 107
From: Denver, Colorado
When the Disco was first built, it was designed for an in-line 4 cylinder diesel, leaving plenty of run for air flow, we no longer have that.
I believe 2 things would help improve the under hood temp, better air flow and some sort of header treatment to cut down on the exhaust temp by at least 200 degrees.
So increasing the volumn of air from the condenser fan and treating the headers or wrapping them is the place I would start.
I believe 2 things would help improve the under hood temp, better air flow and some sort of header treatment to cut down on the exhaust temp by at least 200 degrees.
So increasing the volumn of air from the condenser fan and treating the headers or wrapping them is the place I would start.
Winching
Joined: Oct 2008
Posts: 579
Likes: 12
From: Auburn, AL
Interesting, Buzz. I'll run a similar test to see how the numbers look with a stock thermo. I would think we would see a greater difference in ECT if the engine were warmer to begin with. But based on your numbers there is a definite relationship between IAT and ECT, albeit minimal in your case. I'm out of town at the moment but I will be back soon and will get some numbers. I don't know if I'll be able to hit 60 with the hood open where I live.
Super Moderator
Joined: Jan 2011
Posts: 16,322
Likes: 88
From: Savannah Georgia
No snorkle, but the Gulf States Rovers had an air intake that came thru the side of the fenderwall, at least in the RAVE.
I drove around all afternoon (like four hours at idle and slow) in SWMBO ride, a Kia mini van, 180 - 183F, even in stop and go traffic, AC on, IATs went from 97 on freeway to 154. It is a 3.8 liter aluminum V-6 with electric fans.
My take is as follows:
1. My rodded out rad is better than it was we I bought it, but may not be as good as one of those brand new aluminum $235 ones that are out of stock.
2. The idea that you would see 12 F change with open hood quickly might happen if your rad is already somewhat stopped up with sludge or mud.
3. The side strips out let me feel heat coming out at idle between the hood and fender. But not enough to make a difference at idle or on the road. You would really need something about 20 X 20 inchs (size of the 18 inch fan).
4. The AC making such a big jump at idle show me that we still have too small of an air flow at idle. I measured this in the past, and my larger fan was producing about 800 feet per minute air speed, with electric fans on that went to about 1100 fpm. Note that is not cfm. Of course, at 60 mph we are getting 5,280 fpm air flow. And it makes my main rad look like it is just keeping up before AC thrown on.
5. Another test that could be done in a D1 is to unscrew the IAT and let it dangle under the hood, but it is already mounted in the plastic air box, which has both the trumpet and several drain holes that allow air intake from under the hood.
6. IMHO cutting holes in the hood to add a couple of scoops like the old Dodge Coronet R/T's had would not do much. Just not enough square inches.
7. If you are at idle with AC on for long periods, like search and rescue incident command; or waiting on SWMBO emergency pedicure, popping the hood will help.
I drove around all afternoon (like four hours at idle and slow) in SWMBO ride, a Kia mini van, 180 - 183F, even in stop and go traffic, AC on, IATs went from 97 on freeway to 154. It is a 3.8 liter aluminum V-6 with electric fans.
My take is as follows:
1. My rodded out rad is better than it was we I bought it, but may not be as good as one of those brand new aluminum $235 ones that are out of stock.
2. The idea that you would see 12 F change with open hood quickly might happen if your rad is already somewhat stopped up with sludge or mud.
3. The side strips out let me feel heat coming out at idle between the hood and fender. But not enough to make a difference at idle or on the road. You would really need something about 20 X 20 inchs (size of the 18 inch fan).
4. The AC making such a big jump at idle show me that we still have too small of an air flow at idle. I measured this in the past, and my larger fan was producing about 800 feet per minute air speed, with electric fans on that went to about 1100 fpm. Note that is not cfm. Of course, at 60 mph we are getting 5,280 fpm air flow. And it makes my main rad look like it is just keeping up before AC thrown on.
5. Another test that could be done in a D1 is to unscrew the IAT and let it dangle under the hood, but it is already mounted in the plastic air box, which has both the trumpet and several drain holes that allow air intake from under the hood.
6. IMHO cutting holes in the hood to add a couple of scoops like the old Dodge Coronet R/T's had would not do much. Just not enough square inches.
7. If you are at idle with AC on for long periods, like search and rescue incident command; or waiting on SWMBO emergency pedicure, popping the hood will help.
Last edited by Savannah Buzz; Sep 2, 2012 at 05:16 PM.
Rock Crawling
Joined: Mar 2011
Posts: 369
Likes: 14
From: Forest, VA
Runcool vents
My hunch is that having the vents will provide some additional under hood cooling. Having said that, I'm not sure it's going to make a huge difference on engine temp or longevitity over the long term...
Runcool is nearby to me in Richmond - next time I visit my daughter there I'm thinking about stoping by and seeing if they have an actual storefront. I might install these this winter just for the hell of it...
DRW
Runcool is nearby to me in Richmond - next time I visit my daughter there I'm thinking about stoping by and seeing if they have an actual storefront. I might install these this winter just for the hell of it...
DRW
Thread Starter
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Recovery Vehicle
Joined: Sep 2009
Posts: 1,135
Likes: 14
From: Roanoke Valley, VA
Where can you get one of these fans that you know will fit the D2?
