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My 1995 Hummer HMCO build

Will L.

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Location
Boulder City Nv
I have lost more pics than I care to think of, and just did some pics of my hoodscoop on HummerNetworkforum so figure I can start my build thread with it here.

I bought my hummer in 2002 or 2003. Green metallic paint with tan interior. 6.5 non turbo, db2. Hmco means soft top aka open top 4 door with Cepek 16.5 aluminum rims and goodyear GS-A tires (i still miss those).

I am second owner, p.o. put 30,000ish miles on it. Rich highschool kid drove it to school and got rid of it after college. So it had a rod knock when I got it. Compression was down because he obviously got it to hot, i nursed it along until Dec 2004 when I bought an optimizer from Towbin Hummer dealership. It is the truck block - no centermount turbo oil holes and head to intake manifold bolts at different angle than turbo hummer - but n/a hummer and pickups use same heads, so I reused my intake and was on its way. Cylinder walls #7 was cracking but not leaking yet and #8 cracked properly. All 8 spots between valves cracked. The rest of the engine was ok, but Dan Towbin gave me $1,000 core so it went away.

Hummers overheat worse than pickups with 6.5 because of the radiator angle. I had the opportunity to get my hummer into a huge wind tunnel in SoCal that is ran by Nasa. We (as in I welded and used my hummer as test dummy) and a few nasa engineers and one from AM General did all the math and design. I threw in my 2 cents along the way and we tested about 20 versions. We also bolted on 2 pre made ones that AM General bought from regular hummer suppliers- one of which Bill Heath laid claim to as a modified version of the one he was in on- but got altered for aesthetics.

There was one version that did better than the one on mine with these pics to follow. But it just had the roof and walls extend out to the front edge of the hood and did about 2% better than this one. Problem is grille to hood fitment wasn’t always perfect on hmmwv/ hummer, and the added performance just wasn’t worth the little gain imo.

So here is pics of the hood. I will try to find a “how I bought the truck” pic later. Most of these pics are the hood sitting on my roof rack in my garage. The muddy pic is with the original rush guard- which barely stops a hair brush. It went away many moons ago.

This scoop is tapered in at top, and wider front than rear, Top piece is convex slightly. Those little changes made descent changes in flow surprising to me. Better flow occurs to remove all the internal bracing except the center one needed for support, and vertical ware mesh. But was such a small improvement I never did it to mine. We tested that on a hmmwv that was there.

We also did testing using a remote driven fan from electric motor. It didn’t have huge impact spinning or not because the fan was not the limiting factor- it is the air pocket created from the vertical windshield that causes the air to flow over the top grille like a angled windshield should. Horrible turbulence- the engineers just laughed and laughed at the brick wall on wheels. 6BDCC0F8-EBB7-4E42-84E8-F42E46164F43.jpegCD8FC1D5-97D8-4B1A-97AB-4F7A1B7B9B37.jpeg2CA7FD8D-6D2E-4422-A328-E54E4EBA06C6.jpeg56B17B96-2781-4085-967E-76AA42A0CA56.jpegEC0B999B-0198-4ED8-AB92-A9572A895286.jpeg5C10D530-3944-4248-8A66-522463C44E13.jpeg8F77DE4C-1DAD-47AC-A397-9D09010F98B6.jpeg7E7E4DEE-CBF9-41A6-9B5E-DA87858EFB84.jpeg4F93C27C-C2E3-47F8-B906-B3EF55B6938C.jpeg11093681-5D54-4A38-AFB1-C16A393D3D14.png
 
Then based on which side, it is usually #7 or #8.
If the waterpump is not a balanced flow system, you have 90% chance it is #8.

pics and story in the end please, what are you working on?
 
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