Driving with the hood Unlatched??
07-07-2013, 08:38 PM
#1
Race Director
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Driving with the hood Unlatched??
Yesterday I was driving home from Englishtown on the Garden State Parkway, and when there was no traffic, I was able to cruise at 80-85 mph, & my water temp was about 190 deg..
As I hit traffic and had to slow to 50 - 55 mph the engine temp went up to 210 - 212 (outside air temp was 105 deg),
I pulled the hood latch to release the hood & let the back lift about 2" and this seemed to work & my engine temp went down to 200 deg..
This was the first time I EVER encountered such high engine temp.. I'm thinking the the Vararam intake & Trans cooler are blocking a lot of air the would normally hit the radiator...
I'm not too worried about it as we never get these high temps.. Also I have a manual (Casper) switch that I can use to manually run the fan on Hi or Lo speed if I see the temps go much over 205 deg...
Anything wrong with driving with the hood popped open as I did yesterday ? Has anyone tried it in HOT weather..
What kind of engine temps are you guys seeing in 100 deg outside temps if you have a "VARARAM" intake ?
As I hit traffic and had to slow to 50 - 55 mph the engine temp went up to 210 - 212 (outside air temp was 105 deg),
I pulled the hood latch to release the hood & let the back lift about 2" and this seemed to work & my engine temp went down to 200 deg..
This was the first time I EVER encountered such high engine temp.. I'm thinking the the Vararam intake & Trans cooler are blocking a lot of air the would normally hit the radiator...
I'm not too worried about it as we never get these high temps.. Also I have a manual (Casper) switch that I can use to manually run the fan on Hi or Lo speed if I see the temps go much over 205 deg...
Anything wrong with driving with the hood popped open as I did yesterday ? Has anyone tried it in HOT weather..
What kind of engine temps are you guys seeing in 100 deg outside temps if you have a "VARARAM" intake ?
Last edited by jpee; 10-14-2013 at 10:21 PM.
07-07-2013, 09:37 PM
#2
Team Owner
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St. Jude Donor '13
Both our previous 2006, and now our 2009; normally run coolant at ~195 on the highway, that quickly climbs to ~ 215 in traffic. No problems, the two cars combined would have 105,000 miles.
If you had to slam on the brakes, is it possible for the hood to flip forward?
If you were in an accident, could the hood get jammed rearward through the windshield?
I T-boned a moron at about 35 mph in our 2006, IIRC the rear of the hood was still latched even though everything forward of the doors was a mess.
If you had to slam on the brakes, is it possible for the hood to flip forward?
If you were in an accident, could the hood get jammed rearward through the windshield?
I T-boned a moron at about 35 mph in our 2006, IIRC the rear of the hood was still latched even though everything forward of the doors was a mess.
Last edited by Gearhead Jim; 07-07-2013 at 09:40 PM.
07-07-2013, 10:14 PM
#3
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I would not drive like that, just my opinion. As far as the temps... that is very normal and nothing to worry about. If you were hitting 250 then it's time to worry. I copied this off the web and it sounds pretty accurate.
Cars operate in a wide variety of temperatures, from well below freezing to we*ll over 100 F (38 C). So whatever fluid is used to cool the engine has to have a very low freezing point, a high boiling point, and it has to have the capacity to hold a lot of heat.
Water is one of the most effective fluids for holding heat, but water freezes at too high a temperature to be used in car engines. The fluid that most cars use is a mixture of water and ethylene glycol (C2H6O2), also known as antifreeze. By adding ethylene glycol to water, the boiling and freezing points are improved significantly.
Fluid - Freezing Point - Boiling Point
Pure Water: 0 C / 32 F - 100 C / 212 F
50/50 mix of C2H6O2/Water: -37 C / -35 F - 106 C / 223 F
70/30 mix of C2H6O2/Water: -55 C / -67 F - 113 C / 235 F
The temperature of the coolant can sometimes reach 250 to 275 F (121 to 135 C). Even with ethylene glycol added, these temperatures would boil the coolant, so something additional must be done to raise its boiling point.
The cooling system uses pressure to further raise the boiling point of the coolant. Just as the boiling temperature of water is higher in a pressure cooker, the boiling temperature of coolant is higher if you pressurize the system. Most cars have a pressure limit of 14 to 15 pounds per square inch (psi), which raises the boiling point another 45 F (25 C) so the coolant can withstand the high temperatures.
Cars operate in a wide variety of temperatures, from well below freezing to we*ll over 100 F (38 C). So whatever fluid is used to cool the engine has to have a very low freezing point, a high boiling point, and it has to have the capacity to hold a lot of heat.
Water is one of the most effective fluids for holding heat, but water freezes at too high a temperature to be used in car engines. The fluid that most cars use is a mixture of water and ethylene glycol (C2H6O2), also known as antifreeze. By adding ethylene glycol to water, the boiling and freezing points are improved significantly.
Fluid - Freezing Point - Boiling Point
Pure Water: 0 C / 32 F - 100 C / 212 F
50/50 mix of C2H6O2/Water: -37 C / -35 F - 106 C / 223 F
70/30 mix of C2H6O2/Water: -55 C / -67 F - 113 C / 235 F
The temperature of the coolant can sometimes reach 250 to 275 F (121 to 135 C). Even with ethylene glycol added, these temperatures would boil the coolant, so something additional must be done to raise its boiling point.
The cooling system uses pressure to further raise the boiling point of the coolant. Just as the boiling temperature of water is higher in a pressure cooker, the boiling temperature of coolant is higher if you pressurize the system. Most cars have a pressure limit of 14 to 15 pounds per square inch (psi), which raises the boiling point another 45 F (25 C) so the coolant can withstand the high temperatures.
07-07-2013, 10:32 PM
#4
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Agree. The temps sound normal. My 07 will be in the 204-205 range normally. Hot weather in L.A. area for us is about 80-85 degrees. It might reach +/- 215 when sitting in traffic at that time. In very hot conditions (90+) and sitting in traffic it reached almost 220. But, goes back down to my low to mid 200's when I started moving again. I have the factory thermostat.
07-08-2013, 12:01 AM
#5
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During the summer here, it doesn't get down to 100 real often. 
So staying cool is a serious thing in Phoenix.
Because the Vararam blocks a small portion of direct air flow (it's not as much as you think), I utilized the central area of the bottom feed flow for my trans cooler and mounted it horizontally instead of vertically.
I've been keeping an eye on temps recently, since they are constantly exceeding 110 and I'm trying to determine if I need to reroute the trans lines to also run through the radiator for additional cooling.
So far, if I can drive at fairly constant speeds above 35 MPH, the coolant will stay around 190 and the trans around 160. If I'm in light or average traffic and catch a few red lights it becomes 205-210 and 170. If it becomes heavy stop and go traffic and most red lights, it can easily go to 225-230 and 210 or more. As soon as the traffic flows steady for a couple of miles, it'll drop to the light traffic numbers again. Unfortunately, the oil takes a lot longer to drop and that makes the coolant rise more rapidly if the traffic slows again.
If I hit anything over 240, it's time to flip the heater on to max and drop the windows.
Just so you know, I also have a 3600 stall, catless headers, 160 stat, fans 90% by 201, and I removed the rear hood seal.
So staying cool is a serious thing in Phoenix.Because the Vararam blocks a small portion of direct air flow (it's not as much as you think), I utilized the central area of the bottom feed flow for my trans cooler and mounted it horizontally instead of vertically.
I've been keeping an eye on temps recently, since they are constantly exceeding 110 and I'm trying to determine if I need to reroute the trans lines to also run through the radiator for additional cooling.
So far, if I can drive at fairly constant speeds above 35 MPH, the coolant will stay around 190 and the trans around 160. If I'm in light or average traffic and catch a few red lights it becomes 205-210 and 170. If it becomes heavy stop and go traffic and most red lights, it can easily go to 225-230 and 210 or more. As soon as the traffic flows steady for a couple of miles, it'll drop to the light traffic numbers again. Unfortunately, the oil takes a lot longer to drop and that makes the coolant rise more rapidly if the traffic slows again.
If I hit anything over 240, it's time to flip the heater on to max and drop the windows.
Just so you know, I also have a 3600 stall, catless headers, 160 stat, fans 90% by 201, and I removed the rear hood seal.
07-08-2013, 12:40 PM
#7
Race Director
During the summer here, it doesn't get down to 100 real often. So staying cool is a serious thing in Phoenix.
Because the Vararam blocks a small portion of direct air flow (it's not as much as you think), I utilized the central area of the bottom feed flow for my trans cooler and mounted it horizontally instead of vertically.
I've been keeping an eye on temps recently, since they are constantly exceeding 110 and I'm trying to determine if I need to reroute the trans lines to also run through the radiator for additional cooling.
So far, if I can drive at fairly constant speeds above 35 MPH, the coolant will stay around 190 and the trans around 160. If I'm in light or average traffic and catch a few red lights it becomes 205-210 and 170. If it becomes heavy stop and go traffic and most red lights, it can easily go to 225-230 and 210 or more. As soon as the traffic flows steady for a couple of miles, it'll drop to the light traffic numbers again. Unfortunately, the oil takes a lot longer to drop and that makes the coolant rise more rapidly if the traffic slows again.
If I hit anything over 240, it's time to flip the heater on to max and drop the windows.
Just so you know, I also have a 3600 stall, catless headers, 160 stat, fans 90% by 201, and I removed the rear hood seal.
So staying cool is a serious thing in Phoenix.Because the Vararam blocks a small portion of direct air flow (it's not as much as you think), I utilized the central area of the bottom feed flow for my trans cooler and mounted it horizontally instead of vertically.
I've been keeping an eye on temps recently, since they are constantly exceeding 110 and I'm trying to determine if I need to reroute the trans lines to also run through the radiator for additional cooling.
So far, if I can drive at fairly constant speeds above 35 MPH, the coolant will stay around 190 and the trans around 160. If I'm in light or average traffic and catch a few red lights it becomes 205-210 and 170. If it becomes heavy stop and go traffic and most red lights, it can easily go to 225-230 and 210 or more. As soon as the traffic flows steady for a couple of miles, it'll drop to the light traffic numbers again. Unfortunately, the oil takes a lot longer to drop and that makes the coolant rise more rapidly if the traffic slows again.
If I hit anything over 240, it's time to flip the heater on to max and drop the windows.
Just so you know, I also have a 3600 stall, catless headers, 160 stat, fans 90% by 201, and I removed the rear hood seal.
My wife wont ride in the vette as I drive with the defrost on set to 90& I try not to ride with her as she drives with the air on and the window open
07-09-2013, 07:12 AM
#8
Race Director
I don't see any harm at that temp in stop and go traffic. I wouldn't risk the potential harm of an unlatched hood to avoid 212degF coolant temps. I have seen those temps in the greater Houston area in the summer with my vettes.
07-10-2013, 04:55 PM
#10
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I once made a pass at the dragstrip like this as I forgot to latch the hood completely. It started to lift at triple digits which freaked me out, don't see a problem doing it on the street though as 210 isn't anything to sweat about, no pun intended.
07-13-2013, 03:26 PM
#11
Melting Slicks
that just sounds dangerous
sitting in traffic is one thing (like the Highway Patrol waiting to AMBUSH US) but once you start moving, I'd be affraid of the hood swinging open, bending hinges, breaking the hood ........................................ .. just sounds BAD 
10-13-2013, 12:51 PM
#12
Unlatching the hood isn't going to give you much as far as cooling, and potentially opens up some other problems. Some have had success bringing down temps with coolant additives, I think Redline makes one. The most important thing is making sure your cooling system is in good repair.
- certainly not everyone is going to agreed, right?
10-13-2013, 08:57 PM
#14
Drifting
^
^ what he said... and here is the proof from MIR last year....THIS is why my avatar has 129.43mph and not more..because I lifted
10-14-2013, 03:00 PM
#15
^^Certainly, good proofed on lift if hood is not latched and secured as designed. Hopefully, thats a lesson learned!
I have never experience hood lift with my so to speak "opened hood" at any speed. But certainly, I am happy with my lower coolant temperature both at city traffic and highway speed - that is enough proof in the pudding for me.
I have never experience hood lift with my so to speak "opened hood" at any speed. But certainly, I am happy with my lower coolant temperature both at city traffic and highway speed - that is enough proof in the pudding for me.
10-14-2013, 04:31 PM
#16
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^^Certainly, good proofed on lift if hood is not latched and secured as designed. Hopefully, thats a lesson learned!
I have never experience hood lift with my so to speak "opened hood" at any speed. But certainly, I am happy with my lower coolant temperature both at city traffic and highway speed - that is enough proof in the pudding for me.
I have never experience hood lift with my so to speak "opened hood" at any speed. But certainly, I am happy with my lower coolant temperature both at city traffic and highway speed - that is enough proof in the pudding for me.
10-14-2013, 05:31 PM
#17
On one of the old post, you mentioned you did try that and doing that would certainly gained more of an opening, all without making any spacers - so I gave it some thought.
Decided if I did, that would diminished the ability to keep water out, at the lower corners, the most worrisome is the corner above the battery. I made the compromise and happy with the outcome after got caught driving in the rain and car washing.
Decided if I did, that would diminished the ability to keep water out, at the lower corners, the most worrisome is the corner above the battery. I made the compromise and happy with the outcome after got caught driving in the rain and car washing.
10-15-2013, 08:56 AM
#18
Melting Slicks
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On one of the old post, you mentioned you did try that and doing that would certainly gained more of an opening, all without making any spacers - so I gave it some thought.
Decided if I did, that would diminished the ability to keep water out, at the lower corners, the most worrisome is the corner above the battery. I made the compromise and happy with the outcome after got caught driving in the rain and car washing.
Decided if I did, that would diminished the ability to keep water out, at the lower corners, the most worrisome is the corner above the battery. I made the compromise and happy with the outcome after got caught driving in the rain and car washing.
10-15-2013, 03:48 PM
#19
Sorry I wasn't clear.
No, I did not remove the weatherstripping. I choose to make the spacers and have the hood propped. I have experienced no ill effects driving in heavy rain and I don't shoot water directly into the crack during car wash.
Some water still can get on top of the battery even without any change in the stock configuration during car wash. But more if without weatherstrip - I did the actual verification.
To further improve and protect the battery connections, I did these weatherproofing for the interim, since relocating battery to the rear is in my plan:
No, I did not remove the weatherstripping. I choose to make the spacers and have the hood propped. I have experienced no ill effects driving in heavy rain and I don't shoot water directly into the crack during car wash.
Some water still can get on top of the battery even without any change in the stock configuration during car wash. But more if without weatherstrip - I did the actual verification.
To further improve and protect the battery connections, I did these weatherproofing for the interim, since relocating battery to the rear is in my plan:
