CI GS

I've seen the homemade ram air systems on here, and it appears that they do work, as they should, since otherwise you're pulling hot air from the engine compartment with the stock setup. Even the little air inlet on the nose of the GS and Z cars offer very little flow into the air filter area.
But I've read about (and experienced) the dreaded surge that happens if you get turbulent airflow to the MAF. In my case, this was caused by me cutting slots in the radiator shroud with my Halltech MF103 (with the Beehive).
So, after reading a number of threads on here, and studying how the Vette Air scoop works, since I already had invested in the MF103, I came up with my own idea of a homemade "ram" air system, using a different approach instead of the slotted shroud.
First I cut the small flat area at the bottom of the shroud/air filter area, where the shroud meets the front frame. I then cut a piece of aluminium that I had lying around and bent it into a shape that would extend down into the area behind the grille to catch some air and divert it up through the slot, into the airbox that is formed by the Beehive. I then used two rivets and pop-riveted the aluminium scoop into the shroud and taped the slots that I had previously cut in the shroud. I tested this system and it certainly feels like it's working and there is no longer any surge whatsoever. I've tested it using the 0-60 feature on my Dashlogic and the 0-60 times dropped from a ~4.2 (I know that's poor) to a 4.0x, so it definitely works, as far as I can tell. Not as fancy as a Vette Air scoop, but for nothing more that the cost of some aluminium plate, some cursing and head scratching to get it to fit, and a couple of rivets, I think it worked out okay. I have some other photos of the finished product, but will post them separately (since I can't figure out how to post multiple photos using my iPad

CI GS

Here's what it looks like from the front, looking through the grille. You can see how hangs down about 2" into the airflow path coming through the grille and diverts the air upwards through the slot.

timd38

Very creative!

CI GS

A couple of weekends ago, I decided to finish the air box by cutting out the remaining two flat areas on each side of the shroud mounting lugs, to get a little more air in the box, and then I used self adhesive heat shield material and pasted that over the entire shroud area to try to insulate the air box a little better from under hood temps. I haven't done the underside of the beehive as yet, but I will do that soon as well, as that probably sees higher temps than the front of the shroud.

CI GS

Since the beehive has a large gap at the back around the air bridge area, which obviously lets hot air in from the engine bay, I used some Moroso Carb Air Pan foam I had lying around and cut a chunk of that and stuck that on top of the radiator support/shroud where the air bridge with some 3M double sided tape. The foam is very collapsible, so the air bridge just squashes it down when the beehive is clipped down, sealing that area off completely. Now, if only Halltech could build this Beehive with a rubber gasket around the air bridge, he might just reinvent the mouse trap...

CI GS

Thanks man. It's just typical of me - somehow, most of my experiments involve bent metal..

CI GS

I've tested it like this over the past couple of weekends and the best 0-60 time I've gotten so far is a 3.92 and the worse was a 4.02, and my IAT is at or within 2 degree of outside air temperatures, once I'm cruising at anything over 40 MPH, and there is still absolutely no low RPM surging, so I'm happy with it.

dev1360

Just prop open the plastic shroud with some bolts. Takes two minutes and it's free.

CI GS

I don't need to do that as I've already cut a gap (3 actually) at the bottom of the shroud. I considered propping the shroud open, but didn't want to push it back any closer to the radiator, as I'm about to install a trans cooler on the car and I need all the space that's there to fit it in front of the A/C core.

corvetteflier

Propping the shroud, even a little, will cause surging and even lean engine codes with the Halltech. I found that out when wind pushed the bottom of the shroud open a few inches further than I had it propped. I still want to let air in, but will be careful to limit the opening I made. At first, it worked great, but when the opening enlarged, I got severe surging and 2 lean bank codes. The fact my Intune leans the AFR a bit contributed to it, but it was the Halltech that was the problem. Once I closed the shroud, problem went away. You system seems be working fine.

timd38

Lots of information here!

CI GS

Here's a better shot of what the plate looks like. I cut and bent it so that it has a "tongue" that hangs down in the area behind the grille to catch some of the incoming air and divert it up into the air box that is formed by the shroud with the Beehive lid.
Note that I had several goes at bending this thing to get it to have the right angle. I did this in my driveway without the benefit of even a bench vies, so it isn't exactly a factory looking piece. This is merely the "prototype"...

CI GS

That's what I've read on here before as well, although some people swear it works for them. I guess it depends on how far you prop it open. From what I've read on these forums, I think the reason mine works is that the opening is smaller and the Halltech filter has an end plate that acts as a deflector. There's is no way that wind can push my shroud open further, as the aluminium plate acts as a brace over the flimsy shroud.
I hope that I don't experience any lean AFR problems after driving it for a bit like you did. I've only put about a hundred miles on it since doing this mod. I'm going to set up my Dashlogic so that I can monitor LTFTs and see what that tells me. I'm happy to get it retuned if it's pushing that much more air.
My real concern with propping the shroud open is that it pushes the back of the shroud up against the front of the A/C condenser core, thereby inhibiting airflow to and through the radiator.

CI GS

Just a couple of caveats:

1. I'm not sure whether this works on the M6 cars as mine is an A6. Someone sent me a PM saying that his M6 GS has a cooler in the way, but I don't think you would have a cooler in the area where you need to cut. However, check it out properly before you cut anything.

2. I'm not sure if and how this mod will affect your tune, as every tune is different. I have a custom tune by Diablew that was tweaked for my car with the Halltech and Pfadt headers, before I did this mod. I'm sure it needs to be fine tuned again to optimise it for the cold air. I will monitor the LTFTs and see if they're showing me that the tune is off a bit. I'll report on here what I find out.

In all honesty, if I were living in the US, I would just buy the Vette Air Scoop, which uses a cut in the same location. The only reason I didn't do that is because the overseas shipping to me along with import tax would have been like 3 times the value of the scoop, and I thought I could tinker and make something that works, although I have to admit that I like the design of the Vette Air scoop better than my "cold air tongue".

hisvett

Here's the difference between the GS A6 and M6; what you are looking at is the radiator on the A6 car....



Now this is my GS M6 car with the factory dry sump oil cooler in front of the radiator;



From what I can see, the M6 cooler shouldn't interfere with your conversion. But my foo front licence plate will.... I may have to rethink unblocking the body air scoop and adding a deflector for rain intake.

Thanks for the info.

dev1360

The very small amount of rain that will get into the engine will not effect it at all.

MR_JLR

What brand kit is used to clean the air filter with this kit?

CI GS

The Halltech filter appears to be a K&N oiled gauze filter, so I am going to use the K&N cleaner and filter oil kit. I haven't actually cleaned mine yet because I haven't managed to put many miles on my car as yet (1856 as of this evening).

VYMIKE

I used a K&N filter cleaning kit on my Halltech filter yesterday. It is insane how the radiator fan pulls debris up into the filter, condenser and radiator.
The drivers side radiator tank cracked on my 2008 Base c6 last weekend, so I ordered a new radiator for it. When I pulled the upper and lower shrouds off, I found dirt, grass, hair? stuck in my condenser and radiator. After I pulled the radiator out, I hosed the condenser off to get everything out.
I hadn't even planned on cleaning my air filter yet. It's only been 3,500 miles since I installed it. When I saw how dirty it was, I changed my mind.

I also decided to prop open the lower portion of the radiator shroud to allow cooler air to the filter. I only propped it open 1 1/4". I used the 2 locations where the pushpins were to do it. I installed a 15mm bolt with flat washer, then another flat washer on the front side of the shroud, followed with a lock washer and nut in each of the holes. The bolts were just thick enough to wedge into the 2 holes in the steel where the factory pushpins go.
After I was all finished, I took the car out on the road. No problems at any speed. Full throttle from a stop, wide open throttle at over 100 mph. No surging, bucking or anything. The car actually feels more powerful now than it did before.

I have the Halltech mf103, VMAX ported throttle body and a custom tune. The car has the factory dual mode exhaust.

VYMIKE

Update:

I had to remove the spacers I used to open up the shroud. They started causing a mild surging when staying steady at any speed. The first day, I didn't notice any problems. It started on the second day. No codes were thrown. It was annoying though.