Free cold air
Thread Starter
Melting Slicks
Joined: Jun 2006
Posts: 2,208
Likes: 1
Free cold air
Someone posted this a while back, but I just got around to doing it. Pull out the two push pins that hold the radiator shroud to the back edge of the front clip. Push the shroud back towards the engine a few inches, and voila! Cold, dense air from under the car now routes to the air cleaner, in my case a K&N Aircharger. No worry about water ingestion, still max flow to the condensor/radiator, but now outside air forced to the aircleaner--not exactly ram air, but a big improvement over keeping the shroud closed. SOTP is there, and it has to be worth several hp at least if the Vararam is supposed to get 30. And the price: 0. I have a funnel of all things holding the shroud open now, but will replace with a turned down dowel to hold both sides equally open. Takes all of 2 minutes and no chance of cutting something you don't want--even the shroud. Back to normal in 30 seconds. Great advice!
Tech Contributor
Joined: Jul 2002
Posts: 14,950
Likes: 264
From: St. Louis, MO
St. Jude Donor '08
Great post. I love FREE mods. I will look into this for my buddy, and if I can, get some HP Tuners logs on IAT with this mod. Wish I'd seen this before!
I did some IAT logging recently at the drag strip. Cool air to the engine is very important, particularly with a stock tune.
My buddy's C6 Z06 (with its factory cold air induction) had IAT at 150 in the staging lanes, and got down to 104 at about 80 mph and stayed there. So the Z06 nose vent does work. Ambient was about 84 at that time.
I have a Vararam on my C6. My scan showed IAT 93 in the lanes and got down to 84 (ambient) by 100 mph. I don't think this mod will do as good as the Vararam from that perspective - the Vararam sucks from in front of the car away from the radiator. See the 53 degree hotter temp the Z06 had which draws from in front of radiator shroud like this mod.
Here's a table of the timing being pulled at very low IAT's. This is a Z06 table but C6 is very similar. Note that my buddy had 10 degrees being pulled at the start of his run, and still 6 degrees when his IAT got down to 104. That's why these C6's love cool weather and the Vararam so much. Of course a tune takes care of that problem too. This free mod is likely a step in the right direction!
I did some IAT logging recently at the drag strip. Cool air to the engine is very important, particularly with a stock tune.
My buddy's C6 Z06 (with its factory cold air induction) had IAT at 150 in the staging lanes, and got down to 104 at about 80 mph and stayed there. So the Z06 nose vent does work. Ambient was about 84 at that time.
I have a Vararam on my C6. My scan showed IAT 93 in the lanes and got down to 84 (ambient) by 100 mph. I don't think this mod will do as good as the Vararam from that perspective - the Vararam sucks from in front of the car away from the radiator. See the 53 degree hotter temp the Z06 had which draws from in front of radiator shroud like this mod.
Here's a table of the timing being pulled at very low IAT's. This is a Z06 table but C6 is very similar. Note that my buddy had 10 degrees being pulled at the start of his run, and still 6 degrees when his IAT got down to 104. That's why these C6's love cool weather and the Vararam so much. Of course a tune takes care of that problem too. This free mod is likely a step in the right direction!
Melting Slicks
Joined: Sep 2005
Posts: 2,670
Likes: 134
From: merritt island fl
C1 of Year Finalist (stock) 2019
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Great post. I love FREE mods. I will look into this for my buddy, and if I can, get some HP Tuners logs on IAT with this mod. Wish I'd seen this before!
I did some IAT logging recently at the drag strip. Cool air to the engine is very important, particularly with a stock tune.
My buddy's C6 Z06 (with its factory cold air induction) had IAT at 150 in the staging lanes, and got down to 104 at about 80 mph and stayed there. So the Z06 nose vent does work. Ambient was about 84 at that time.
I have a Vararam on my C6. My scan showed IAT 93 in the lanes and got down to 84 (ambient) by 100 mph. I don't think this mod will do as good as the Vararam from that perspective - the Vararam sucks from in front of the car away from the radiator. See the 53 degree hotter temp the Z06 had which draws from in front of radiator shroud like this mod.
Here's a table of the timing being pulled at very low IAT's. This is a Z06 table but C6 is very similar. Note that my buddy had 10 degrees being pulled at the start of his run, and still 6 degrees when his IAT got down to 104. That's why these C6's love cool weather and the Vararam so much. Of course a tune takes care of that problem too. This free mod is likely a step in the right direction!
I did some IAT logging recently at the drag strip. Cool air to the engine is very important, particularly with a stock tune.
My buddy's C6 Z06 (with its factory cold air induction) had IAT at 150 in the staging lanes, and got down to 104 at about 80 mph and stayed there. So the Z06 nose vent does work. Ambient was about 84 at that time.
I have a Vararam on my C6. My scan showed IAT 93 in the lanes and got down to 84 (ambient) by 100 mph. I don't think this mod will do as good as the Vararam from that perspective - the Vararam sucks from in front of the car away from the radiator. See the 53 degree hotter temp the Z06 had which draws from in front of radiator shroud like this mod.
Here's a table of the timing being pulled at very low IAT's. This is a Z06 table but C6 is very similar. Note that my buddy had 10 degrees being pulled at the start of his run, and still 6 degrees when his IAT got down to 104. That's why these C6's love cool weather and the Vararam so much. Of course a tune takes care of that problem too. This free mod is likely a step in the right direction!
Thread Starter
Melting Slicks
Joined: Jun 2006
Posts: 2,208
Likes: 1
Wow, I've not seen the tables before. With much colder air and the somewhat venturi effect from the lip of the shroud being out in an active airstream, I would guess more like 10-12 hp available with this mod--especially with the much larger and completely open swept area of the K&N filter. At the 7000 foot altitude here in COS, colder, denser air makes real horsepower--and the price is certainly right!
Drifting
Joined: Jul 2005
Posts: 1,533
Likes: 0
From: az
Drifting
Joined: Apr 2001
Posts: 1,779
Likes: 6
From: LOS ANGELES CA.
I'm stupid!
Someone posted this a while back, but I just got around to doing it. Pull out the two push pins that hold the radiator shroud to the back edge of the front clip. Push the shroud back towards the engine a few inches, and voila! Cold, dense air from under the car now routes to the air cleaner, in my case a K&N Aircharger. No worry about water ingestion, still max flow to the condensor/radiator, but now outside air forced to the aircleaner--not exactly ram air, but a big improvement over keeping the shroud closed. SOTP is there, and it has to be worth several hp at least if the Vararam is supposed to get 30. And the price: 0. I have a funnel of all things holding the shroud open now, but will replace with a turned down dowel to hold both sides equally open. Takes all of 2 minutes and no chance of cutting something you don't want--even the shroud. Back to normal in 30 seconds. Great advice!
Drifting
Joined: Jul 2005
Posts: 1,533
Likes: 0
From: az
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Melting Slicks
Joined: Oct 2006
Posts: 2,905
Likes: 1
I've cut a hole to mimic the area of the K&N on the radiator shroud. I plan on sticking weather striping to seal it up a bit better . This shouldn't cause any reduction in the air to radiator and increase the air to the intake. Real easy, removed the K&N, used a box cutter to remove a rectangle area, replace K&N. There was no obstructions in the way, yet I've heard of people slicing their a/c lines here. Where are they cutting?
Team Owner
Joined: Feb 2001
Posts: 27,254
Likes: 136
From: Short Hills, NJ
I love my free semi cold air mod, I haven't track tested it yet (not sure if I even will) but it really seems to make sense that it will give at least some gains.
I also took off the rain guard/cover, cut the tops off of the air filter housings and put in some Fram Air Hog high flow filters (I normally prefer K&N products but these had a rebate for $20.00 off on each one, I paid under $24.00 shipped for each one before the rebate.
)
I also took off the rain guard/cover, cut the tops off of the air filter housings and put in some Fram Air Hog high flow filters (I normally prefer K&N products but these had a rebate for $20.00 off on each one, I paid under $24.00 shipped for each one before the rebate.
)
Tech Contributor
Joined: Jul 2002
Posts: 14,950
Likes: 264
From: St. Louis, MO
St. Jude Donor '08
No but my buddy's Z06 with factory CAI was 150 in the staging lanes. 11 degrees of advance is about 1/2 of what the car calls for absent timing being pulled by IAT tables.
This is, in my opinion, why we have such a variety of bone stock drag strip results at the stick at the top of the page. One common theme for the low 12 bone stock cars... they did the runs in cold weather. If you go to the track on a 50 degree day and start with a cold engine, you will get the full timing and performance your car will have. On the other hand, if you go on a 90 degree day like me and wait in the staging lanes for 20 minutes, your IAT will be 150 and you will have 11 degrees of timing. That cuts performance dramatically, as you know.
It's also my theory that this is why the Vararam is so effective on stock cars. On an 84 degree day my Vararam car in the same staging lane had 93 degree IAT vs 150 on the stock intake of my buddys. A C6 would be worse than a C6 Z06 btw, the Z06 has a functional vent in the nose. As you can see much less timing is pulled at 93 degrees vs 150.
This is, in my opinion, why we have such a variety of bone stock drag strip results at the stick at the top of the page. One common theme for the low 12 bone stock cars... they did the runs in cold weather. If you go to the track on a 50 degree day and start with a cold engine, you will get the full timing and performance your car will have. On the other hand, if you go on a 90 degree day like me and wait in the staging lanes for 20 minutes, your IAT will be 150 and you will have 11 degrees of timing. That cuts performance dramatically, as you know.
It's also my theory that this is why the Vararam is so effective on stock cars. On an 84 degree day my Vararam car in the same staging lane had 93 degree IAT vs 150 on the stock intake of my buddys. A C6 would be worse than a C6 Z06 btw, the Z06 has a functional vent in the nose. As you can see much less timing is pulled at 93 degrees vs 150.
Thread Starter
Melting Slicks
Joined: Jun 2006
Posts: 2,208
Likes: 1
Thread Starter
Melting Slicks
Joined: Jun 2006
Posts: 2,208
Likes: 1
I've cut a hole to mimic the area of the K&N on the radiator shroud. I plan on sticking weather striping to seal it up a bit better . This shouldn't cause any reduction in the air to radiator and increase the air to the intake. Real easy, removed the K&N, used a box cutter to remove a rectangle area, replace K&N. There was no obstructions in the way, yet I've heard of people slicing their a/c lines here. Where are they cutting?
Burning Brakes
Joined: Jan 2007
Posts: 968
Likes: 122
From: Lighthouse Point FL
I have been watching the threads on this mod, and I like free stuff too!
One thought that occured to me is that the air that is brought into the nose of the car by this mod would just flow over the radiator support and back over the engine, correct?
If there was a way to create a seal between the hood and the radiator support, would positive pressure be created in this area? The positive pressure should have an additional benefit (ala Vararam) in addition to the lower IAT.
Any ideas on how such a seal could be created? Closed cell foam with the air bridge running through it, glued to the radiator support and trimmed to the contour of the underside of the hood?
One thought that occured to me is that the air that is brought into the nose of the car by this mod would just flow over the radiator support and back over the engine, correct?
If there was a way to create a seal between the hood and the radiator support, would positive pressure be created in this area? The positive pressure should have an additional benefit (ala Vararam) in addition to the lower IAT.
Any ideas on how such a seal could be created? Closed cell foam with the air bridge running through it, glued to the radiator support and trimmed to the contour of the underside of the hood?
Tech Contributor
Joined: Jul 2002
Posts: 14,950
Likes: 264
From: St. Louis, MO
St. Jude Donor '08
It's cylinder pressure. I think the MAP sensor measures it, that would make sense to me but I'm not 100% sure. I know this - when the engine is under load it is higher. Full throttle on the drag strip puts you in the lower right columns. I think the only way you go above 1.0 (really .9) is with forced induction.
Drifting
Joined: Jul 2005
Posts: 1,533
Likes: 0
From: az
vredvette came up with the idea. I couldn't find his post, so reposted it after I did it. I just read last night that 1 degree F lower intake air is worth 1 hp. So, even if you just get 15 degrees cooler air, which is a very real prospect, for 0 $ you pick up 15 hp. Not a bad bang for the buck.
http://s155.photobucket.com/albums/s...ent=grill4.jpg