A.I.R and exhaust questions....

Discussion in 'The Garage' started by ryoken, May 16, 2006.

  1. ryoken

    ryoken Puppy Fabricator Premium Member GMOTM Winner

    Jun 13, 2003
    Likes Received:
    Jersey Shore
    Ok, bare with me here guys...

    A recent "evacuation" of my muffler and tailpipe have bumped my exhaust system up the "to do" list.. :wink1:

    While researching exactly what I want to do, I came across a curiousity to me... Aren't A.I.R systems supposed to have a hose running down to the cat? Aren't alot like that? What are the difference in those system styles?

    Mine doesn't have it, which is fine by me.. I have the single pipe fitting in each forward exhaust port. (anyone know that thread size? 3/8's NPT?), then those tubes go back to the diverters, driverside comes around back of motor to passenger diverter. then that pass. diverter has an extra pipe that goes to the smog pump. pump has that and another coming out to the air cleaner..

    This brings up Part 2 of my storie here... I want to maintain that single out of each bank,A.I.R in my header choice... I do not want the 4 tube per bank style for multiple reasons...

    Still trying to find out if that one is available in Thorley's.. They indicate A.I.R on this one.. but not which style...


    part 3 of the novel... Any thoughts on my below exhaust decisions?

    I've tossed back and forth single vs dual a long time... started wanting dual, then convinced myself to go single... Now I'm pretty certain I'm going dual again...

    I hated the single idea, mainly due to the whole y-pipe clearence thing, not any performance reason.. I know its another run of pipe down that tight transfer case side, but I've decided to go 2 1/4 on my pipe size to help that out size and bending wise...

    then a pair of highflow cats and I'm leaning torwards a pair of Delta 50 Flows on either side.. I would have been open to another brand of muffler, but that is what my exhaust guy likes to use... I definitely want as much "tone" as I can get and want to keep my mufflers small.. but I'm afraid any 40 series will be just a little loud for Johnny law, heck you should here me right now.. :haha:

    One reason I was gonna go single was for legal reasons...didn't want any inspection hassle for the duals, but I'm saying screw it, I'm doubting anyones gonna question that... And I can't remember the last time I went to state DMV and didn't have a "friend" run it thru anyway...

    Initially I don't think I'm gonna put a crossover in.. Think I'll wait till my lift is done so I can see that front shaft location.. Then maybe add a x-over up there... Should be a good location right behind the headers and hopefully I can run it so it wont be hanging low like I was so concerned with about the y-pipe.. kinda ironic... :haha:

    Thoughts on any of this will be mucho appreciated... :D
  2. dyeager535

    dyeager535 1 ton status Premium Member

    Dec 13, 2000
    Likes Received:
    Roy WA
    AIR injection depended on the vehicles. I don't think the C/K/R/V trucks our vintage ran a cat with the AIR input, but the cars the same vintage AFAIK all did.

    The single vs. 4 AIR input I haven't seen worked around on headers. If the headers have AIR, all I've seen are 4 port, but if there is an emissions legal header for your truck, then it should be set up the way you need. I'd probably look at stuff that was CA legal to be sure though.

    I honestly think that single 3" is the way to go. Yes, the Y-pipe can be a bear, but single 3" is going to save money and time when it comes to routing and the additional hardware duals require.

    The only positive I have to say about true dual exhaust is that if there is a problem with one bank of the engine, you know where it is if there is smoke, etc. Other than that, its pretty pointless anymore. Again, IMO, but I've got true duals, and I may or may not stick with them when the time comes to replace. Mines the stock diesel system I got for free, so it didn't take much effort or money to use it.

    If I was starting from scratch, or replacing everything, I don't see a reason to do anything other than single 3" now.

    Dual converters are federally illegal on your truck, so it really does depend on the inspection station/inspector as to what you can get away with/what they look at. I knew someone that had a friend at the DMV, he had problems with emissions when that person no longer worked there.

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