hi, i have a 1993 c1500 5.7 lwb and i was wondering what the tube running from the bottom of the air air filter housing down to the engine exhaust header does. does it have to do with the egr system? would the engine have more power if i put an air filter on that is exposed? would it hurt the computer?

 

That warms the engine up faster by taking the hot air off of the exhaust manifold and running it up to the throttle body. If your not in a cold state than you really don't need it. Most trucks are missing it anyways.

 

took my whole air filter assembly off and replaced it with a 14" edelbrock exposed air assembly ( and riser was necessary ) and there is noticeably better throttle response. Thing screams better at full throttle now too (had to let it stretch its legs out Just put it on so don't know yet about mileage. Hoping theres an improvememt though.
That tube is just there to warm up intake air for cold starts. Mines the only one ive ever seen that still had one on it until I took it off. Its a cute idea but when you first start you're pickup the manifold isn't warm for a minute or so anyways, enough to matter that is.

 

Looks good!

CAI and Open air cleaners like you installed will definetly wake your truck up and give you more noticeable HP at WOT, I would not look for any improvement in MPG and here is the reason.

Horsepower is SOOOOOOOOOOOOOOOOOOOOOOO! much fun it's hard to keep your foot out of it, Bad Foot.

Have fun

jvp

 

It is required to be on there for state inspection but you can run it without it after that.

 

Most inspection stations ignore that heat riser tube anyhow... from my exprience. The open air filter is a neat idea, but unfortunately your MPG will not change that much. And really only at wide open throttle is where you will notice the difference. Mostly what you are hearing is the air being sucked into teh system. I use to run my air box lid upside down to get the same results. Now if you really want to make a differnce in the way it runs. Design a ram air kit for your 5.7 like I did then you will really notice a difference in MPG and performance. Just my 2 cents though.

 

I have thought about making some sort of duct work that will tie into my stock air box and plumbing it into a spot where air rushes in alot. And I actually can't really hear air rushing in that much unless really listening for it. I'm curious......what did you design?

 

What I did was turn the original box counter clock wise so the snout faced towards the drivers side headlight. Notched the stock riser so it fit like stock. Then I took the V6 stock ducting and ran it towards the drivers side headlight angled down. Then I drew up a design of a tube welded at an agle attached to a flat peice of square metal. Had it fabricated. Then I took a door **** drill bit and marked a place beside the radiator; centered between the top and bottom of it. Obviously put a hole there and enlarged it to teh size of the metal tube. I beleive the tube size was the size of a medium size coffee can. bolted it all together and walla... Oh and I had shorty headers on mine and installed the heat riser tube on teh drivers side header. I also had and Edelbrock intake, Hypertech thermomaster chip, under drive 3 peice pulleys, K&N air filter and single in dual out glasspack exhaust. Stock motor. I would average 22 MPG at 75MPH on the freeway. However I had a 2 wheeler, regcab shortbed, 5.7 with 373 gears and a tonneau cover too.