Reply With QuoteWhat is a Q-Jet?
J/K.
I am sure some of you are wondering what the heck a Q-junk is doing on ***boat and your right...there isn't much use for one on a high performance boat....Or is there?
I just wanted to show you the preliminary stages of the build I am performing on this Q-jet. It's being installed in a 67'Chevy truck on a small block. She's getting powdercoated this Friday in Canary Yellow.
Notice what she looked like when it showed up in the shop. What a piece of junk. I nearly turned it away, but then again I like a challenge. All in all there were only minor parts replaced other than the normal overhaul provided.
This is with the top off. What a site for sore eyes. eek!
This thing had so much dirt inside I was worried about damaging something while moving the shafts to clear the plate.
These are pics of the machine work. All casting flash is removed and deburred. This allows for a better shine once powdercoated, let alone less bloody knuckles.
Notice the amount of material carefully removed to improve the air-flow. There was so much casting flash inside I would have worried about some of it coming loose. That's ok though, because I took care of it. The air-flow is now balanced and the signal will be stronger. This will help with a better top-end response.
Now just inside the inner venturi region I will machine a small step into this area to improve the fuel shear and increase the level of fuel atomization. Not that this primary needs any better throttle-response, it will though improve the gas mileage some.
I will get her back next Tuesday from the metal finisher. Even the flappers (as I call them) and linkage will all be Zinc coated to extend the life of this carburetor some more.
Stay tuned...
What is a Q-Jet?
J/K.
Not to sound off color, but other than class restricted racing why would anyone want to use a q jet??
As I stated before, there really isnt an affordable use for this carb on a Marine application. With the amount of time and parts being engineered into this carb its use for Marine would be better off ignored in favor of a Holley.
Now for street use this carburetor rocks! You can see for yourself that the triple venturie offers great throttle response and fuel mileage and with proper preparation the fuel will be delivered a lot better. Once the secondary opens the performance gains can be quite astonishing despite what one might think.
Thanks to marketing and the ease of tuning, the Holley has been the preferred choice. But with so many Q-jets lying around folks garages, one can be sent in to me to be overhauled and modified cheaper than it would cost to buy a comparable Holley. I have a larger Q-jet slated for build late next week that should do just fine up to 500HP. It just takes a little more time to massage one then a Holley.
For those people out there that dont want to ditch this toilet there is always an alternative with sending it in to me.
Ok, cool. What about them plastic thermo quads, I have one of them you can have.
Hi 472 - I will TAKE it ! Thx, Eric
I run Q-jets on my jeeps as they work much better off road than any Holley carbs that I have found. Ty I am building a new rock crawler type jeep and need to freshen up the Q-jet. Will give you a call when it gets a little closer.
I've done alot of work with Q-jet carbs and I will say that they can be made to run as well as any Holley. The part throttle metering is much better as well as low/mid rpm throttle response. The only area the Holley is better is at WOT, the Holley makes slightly more power. The biggest problem I have encountered is raw fuel leakage into the engine from jetwell plugs coming loose. A small dab of epoxy will cure the leak. The biggest drawback to a Quad is lack of tuning parts [metering rods, jets and springs] and they aren't as tuneable as the Holley.
SK48,
I should be complete this week with the Q-jet we overhauled recently. It's coming back from the powdercoater this week, Canary Yellow!
I am also building one for a local off-road shop in a couple weeks for display purposes. These Q-jets when tuned properly and all the bells and whistles really smoke the competition. Holley double pumpers and vacuum secondaries with the Dominator bowls just don't cut it for Off-road use on climbing.
Now since everyone seems to have a Q-jet collecting dirt around the yard, performance is just a UPS truck away from revival.
I'll keep everyone posted on the build-up...
~Ty
[ March 16, 2003, 12:25 PM: Message edited by: Hotcrusader76 ]
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I've done alot of work with Q-jet carbs and I will say that they can be made to run as well as any Holley. The part throttle metering is much better as well as low/mid rpm throttle response. The only area the Holley is better is at WOT, the Holley makes slightly more power. The biggest problem I have encountered is raw fuel leakage into the engine from jetwell plugs coming loose. A small dab of epoxy will cure the leak. The biggest drawback to a Quad is lack of tuning parts [metering rods, jets and springs] and they aren't as tuneable as the Holley. I agree 100%, the qj is a great carb when properly built and modified. And they are tuneable by changing metering rods, I've done it. I wouldn't choose it for a WOT race application but would definately run one in street or strictly ski application. Better fuel economy than a "performance" holley when tuned properly too.
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