Dismiss Notice

Welcome To CK5!

Registering is free and easy! Hope to see you on the forums soon.

Score a FREE t-shirt and membership sticker when you sign up for a Premium Membership and choose the recurring plan.

SMI Stage II Qjet Review

Discussion in 'The Garage' started by noahrob, Mar 12, 2006.

  1. noahrob

    noahrob 1/2 ton status Author

    Joined:
    Nov 26, 2005
    Posts:
    1,878
    Likes Received:
    1
    Location:
    Santa Barbara
    VERY LONG...

    As the title says, this is a review of the process in deciding which carb to get, acquiring it, installing it, and the results to date. If you want any more details, PM me and I will do my best to respond. I am a hack, and this is just my experience, so if you have had a different experience, I cannot speak intelligently about that, but feel free to add to this as if it helps someone...great.

    Backgroud:
    I have a 1973 Blazer with a 383 roller, headers, and a mild Comp cam that was running an old Carter with sprung needles and a few other customizations. My truck stalled a lot, so much so that everybody who rode with me got used to rolling down hills backwards with the engine off (not always fun).

    Selection:
    I read a lot on this site about the Truck Avenger, Qjet, and Demon Trucker and originally decided it was between the Holley and Demon, and I did no t even consider the Qjet, mostly because growing up I had always heard "Quadrajunk" and was hesitant to go near it. Here is the link to some questions I had

    http://coloradok5.com/forums/showthread.php?p=1487047#post1487047

    Finally, I talked to Sean Murphy at SMI and he basically told me that the Qjet has the best design for offroading because of where the fuel bowls are. Instead of fuel sloshing over and dumping down the intake like with a Holley, the fuel bowl was located in the middle of the of the throttle body. Now keep in mind, I don’t know d*ck about carbs so I did some more research on this site and a lot of guys were really hyping up the Qjet. Based on Sean’s input and the stuff I found on the site, the Qjet won (especially because the Demon was very expensive, and the Holley was going to require tuning whereas in theory, the Qjet should be a bolt on piece).

    Purchase:
    Here’s the deal, SMI has a web page that asks you everything from the lobe of your cam to the year make and model of your car. With all that info (and your credit card number), they build you a carb that’s right for your rig…or at least that is what I understood. Sean told me the build time was three week’s, but after I told him about our trip to “Miller Blazer Trail” on the 18th he was able to get me the carb in time.

    Installation:
    Since I run an Edlebrock intake, there were holes for both a square bore and spread bore carb, which is good because I did not want to use an adapter. I took of the stupid riser I had on there and bolted the Qjet on there (OK, camok5 did this while I was out with my girlfriend…thanks). Throttle cable, a coupe of vacuum lines and 12v ignition to the choke and we were ready to go. (NOTE- The two front bolts are 5/16 x 3 ¾) As it turns out, we had the vacuum advance going to the wrong vacuum on the carb and the thing was dieseling like there was no tomorrow. Once we go that straightened out by hooking the vacuum advance to a line that has no vacuum on idle, but does pull once the RPM’s go up, we turned the idle mixture screw out 4 turns, adjusted the idle and were off…

    Performance:
    [FONT=&quot]To be fair, I should mention that during the process I ditched the high-rise open element for an old TBI air cleaner unit. Results to date have been street only, but I am happy, seems to deliver enough fuel at the right time, not much (if any) in the way of hesitation, and idles well…I will provide an update on what we really want to know…does it stall when the truck is on an incline, after we get back from the “Miller Blazer Trail”[/FONT]
     
  2. noahrob

    noahrob 1/2 ton status Author

    Joined:
    Nov 26, 2005
    Posts:
    1,878
    Likes Received:
    1
    Location:
    Santa Barbara
    OK, so we did some recon this weekend, and here is what I have learned...The qJet is infinitely better than the Carter I had before. On hills that I used to stutter out on, the truck ran strong. I finally got it to stall out when I accidentally got pinned with my front up on a ridge and my rear bumper was wedged on the ground...Even then I technically stalled because my clutch lever fell off and I was still in gear. After being stuck like that for almost 15 minutes, I finally got the truck down and it started up pretty much right away.

    Other interesting points. The electic choke is great and works very well, makes cold starts much easier. The transition from fast idle to normal idle works as it should.

    Freeway cruising is much much better. Specifically, there is no hesitation when I mash it from cruising speed. Also, the fuel delivery seems much more linear while at cruising speed. No popping on rolling slow down.

    The bad. After one particular jag, the truck dieseled pretty badly. However, I am pretty sure that it is a reulst of something I did during setup.


    So, my conclusion is that I am very happy with this carb, although I can only compare it to the Carter that was on before and other cards I have had, not the Truk Avenger.
     
  3. roadnotca

    roadnotca 3/4 ton status

    Joined:
    Sep 16, 2005
    Posts:
    5,433
    Likes Received:
    1
    Location:
    Redondo Beach, CA
    Yo noahrob, for the life o'me I can't figure what you mean by float bowl in the middle. Stock Q-jet basically only needs a bowl vent extension to stop the piss down the primaries, in a climb, cause the bowl is out front.:confused: Come back(?)
     
  4. noahrob

    noahrob 1/2 ton status Author

    Joined:
    Nov 26, 2005
    Posts:
    1,878
    Likes Received:
    1
    Location:
    Santa Barbara
    Well, let's call a spade a spade. If I knew what the hell I was talking about in the first place I would explain. Here is what I thought I understood from my conversation with Sean. The Holleys have the float bowls on the outside which means it is possible for fuel to splash over and down into the intake...The Qjet does not have this same issue. I understand that the bowl is in the front which is why installing the Qjet backwards works great for hill climbs, as the jets are covered with fuel the entire time.
     
  5. roadnotca

    roadnotca 3/4 ton status

    Joined:
    Sep 16, 2005
    Posts:
    5,433
    Likes Received:
    1
    Location:
    Redondo Beach, CA
    My mistake, brain fart. I was remembering my old street Holley. My shot at Top Gun school passed by many decades ago.:haha: Thanks for the review also.
     
  6. camok5

    camok5 1/2 ton status Premium Member

    Joined:
    Jun 25, 2003
    Posts:
    959
    Likes Received:
    13
    Location:
    Buellton, Ca
    Did it diesel on you this weekend while you were out wheeling?
     
  7. noahrob

    noahrob 1/2 ton status Author

    Joined:
    Nov 26, 2005
    Posts:
    1,878
    Likes Received:
    1
    Location:
    Santa Barbara
    Just once...it was odd, big diesel and then a huge puff of smoke...after that, no more problems adn it ran great.
     

Share This Page