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6637 Mod by William

One of the most fun parts of my new truck is all the fun things I can modify and change. While Midnight Mods is mostly a computer site, we divulge in all modding, not just electronic modding. We mod without prejudice!

I want to thank Clay at Riffraff Diesel Performance for donating this kit.

rr6637_2006 Today, we are modifying the stock air system in my 94 Power Stroke. I was in such a rush to get this thing out of this truck that I never did take a good picture of it being installed. The problem with the stock air box is that it leaks. It has poor flow. You can see here, the box on the right of the picture, has the snorkel missing for it. This is an idea that allows less air restriction to the filter. You might think, “well, they designed it all this way for a reason.” Well, it might be safe when this thing was brand new, but when you make things out of plastic, and the fasteners out of plastic, they eventually fail. It was a cheap air filtering solution. So, maybe you might be thinking “why are we worrying about leakages in the filter system, don’t we want more air intake?” Well of course we want more air intake, but this is a Turbo Diesel.

Nate Air Man Cuda Jim

(Thanks to nateairman and Cuda_Jim for the pictures)

This is what we are protecting, these blades right in here. They need to be sharp to work effectively. If we allow dirt and dust though, we are essentially sand blasting the compressor wheel. In the right picture, you can see a dusted and new compressor wheel. We do not want to sand blast the compressor wheel. This mod gives us some air flow and some security in air filtration system.


Now as I had said, I could not wait to get this thing out. This box has a few bolts that screw the bucket, or pan, secure by the fender. There are two long screws that come up from the bottom that allow you to tighten the top down onto the filter. You can see the massive amounts of dirt on the pan and the filter. Yuck! Lets remedy this problem.


rr6637_2005 There we go. Another good shot of how dirty it is, and how worthless this system is. Okay, actually, I did not throw it away. I have it out in the garage. I really do not know why yet. Maybe I’ll load it in the trap thrower for some fun someday.

rr6637_2000 rr6637_2001

The 6637 kit includes a 45 degree, mandrel bent, powder coated 4 inch pipe. This is to make the turn to the filter area. It also includes a SS T-bolt Clamp and the 6637 Tymar Filter. This thing is HUGE! I really cannot hype this up enough. I don’t think you can get much more flow than this filter will give you except if you were to remove the filter.

Okay, so you could be saying, “K&N Filters are way better than this junk, why would I want to do this? Bah Humbug!” Okay, smarty pants, when is the last time you held a K&N filter up to the light and looked though it? You can see though the filter can’t you? Those little spots of light, that is where dust can get though, even if you have the oil on the filter. A reusable style filter actually cleans less when you first clean and recharge the filter with oil. It needs to be dirty to actually work effectively. Even if the filter was filtering well, I still would avoid them. Why?  A Turbo PULLS air though the system, it doesn’t work on atmospheric pressure. I’m not trying to bash K&N, because their products are great for Gas engines, but the sensitivity of a turbo is far to important for me to trust a filter with huge holes in it. I want to be safe. Just to throw more fuel on the fire, and throw in a Dodge reference. They took a Dodge Cummins into the dyno at CMU here, and ran the truck with the stock air filter system for a bench mark, then installed a K&N cold air setup and lost 10 horse power on the next dyno run. You know, just saying. I ran a K&N in my gas truck successfully for years. I just don’t recommend it on a Turbo Diesel.

rr6637_2003 rr6637_2002

Basically we just insert the 45 into the filter, put down the clamp, slide it into the stock tube and clamp it down on the 45. That’s it, your done. Simple, easy. Looks good in there also. Clay’s kit also comes with a Dust Cover for the filter as well. This was a donation to me, so that might be why I did not get a cover. The cover is just essentially a cloth cover that fits over top like a sock, and you can remove and wash. This will help your filter last a bit longer due to the sock picking up most of the big dust, and allowing the filter to get all the small stuff.

This kit is available for the 94.5-97, and the 99-2003.
94.5-97 6637 Kit
99-03 6637 Kit

If your wondering why you should order this kit from Clay instead of doing the kit on your own, you should call down to Napa where you get the filter and ask them the price. they will tell you right around 66 dollars. So, for a few dollars more, your getting a dust cover and the 45 elbow, that is powder coated, to complete the install.

You can also call up Clay and order your part as well. If you do, be sure to tell him I sent you.

Thanks again to Clay at Riffraff Diesel Performance for this donation.

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