I remember reading somewhere or talking to someone , that they built and was running a port fuel injection system , on a Buick V8, using the q-jet aluminum intake and keeping the q-jet as a throttle body. Would that be practical? what I mean is based on all the pre-made kits out there money and time wise? I like what I have for the the q-jet set up in my car , a 82 Regal with a 71 455 bbb in it , Edelbrock Q-jet intake, HEI, headers, 200R4 GN trans, 8.5 GN rear end with 3:42 posi gears, and 28" tall rea tires. The last big trip out I had a trunk full of gear and 2 adults , managed a 18-20 mpg average. I like the set up because of the small diameter primaries in the carb, and on the intake.... with port injection ( as I've heard you get good power and mpg) would it be better with the q-jet carb as a T-body and use the Q-jet intake?
I think you would be hard pressed to get better than 21 MPG with your combo. I would be happy with the Q jet and keep the combo the same. If you do want to look further into the fuel injection talk to this guy: http://www.v8buick.com/showthread.php?208168-TheSilverBuick-s-1977-Skylark
It's all in the cam. EFI won't gain significant mpg's compared to a well tuned carb. Compare a decently tuned efi system to a poorly tuned carb then sure. I'm the one that wants to use a Q-jet for a throttle body for a multiport efi system. MegaSquirt is the only system I'm aware that would be able to do that.
Idea for modern originality? (Re: Q-jet into a Throttle body for Fuel Injection?) Hi Chris, Sean, Randall, and V-8 Buick technology tinkering types, I don't know how practical the idea is. However, it would seem appealing to the originality stickler types. Anyone who wants a really stock appearing engine, but with modern technology might find a "disguised" Q-jet really appealing. As I read the tea leaves, originality freaks want the old-fashioned operation at the moment, so they want an old-fashioned carb. However, that could change because of anything from government regulations to an increased emphasis on driveability. So EFI camouflaged as an OEM carburetor may eventually become a marketable product. Certainly an interesting possibility. Cheers, Edouard :beer
18-20mpg with a 455, sounds good to me. I don't get much better than that with my SFI truck (318 Magnum, 3.55 gears, Auto trans, 2wd, granted probally weighs close to 5000lbs as well) I'm not familiar with the megasquirt system, but if you used a Q-jet as a TB how would you incorporate an Idle Air Control? In theory I would think it'd be easy enough to incorporate fuel injector bungs in any intake manifold.
I hope to do this some day. The appeal is saving ~$400 on having to purchase a large CFM throttle body for EFI when you can find any junky Q-jet, and as long as the base plate throttle blades move freely it'll work, heck the shafts can even leak if you are okay with it being unfiltered air. If I could get one of those Q-jet's with the built in TPS I would use that TPS for the MegaSquirt, otherwise get a TBI tps sensor and make a bracket to mount it too and tie a string to the tps lever and throttle linkage. I would gut out the boosters in the Q-jet to open of the air flow some, but that is pretty optional. As for idle control that is optional really. On my Thunderbird I don't run any kind of idle air control and it starts even in the cold pretty reliably, but that engine can idle at 500rpm with no problem. What I would do is leave the choke on the Q-jet functional. If it's electric or mechanical. Obviously electric is easier to install with a variety of intake manifolds. But do just like you would with a carb, tap the pedal to set the choke (no fuel squirted in obviously) then start the car and it'll be on high idle. You tune the EFI to work with that, it's pretty simple to do actually. When it's cold the EFI will add extra fuel (an amount you set), the choke will keep the idle high. Actually you could remove the choke butterfly and simply keep the high idle stepper as that is the important part for the EFI. Then when the choke warms up it'll idle down as you drive just like a carb, because well it is a carb. Another option would to simply run an external idle control valve to a large vacuum port. They are out there for sale but I haven't ever seriously looked at them.
thats what my guess was, some sort of external IAC that connected to a plate in the carb (either throttle or choke). My only real experience I've had with FI was on my dodge, so that's what I'm basing my question off. I suppose the carb has a built in idle circuit that is set (adjustable), rather than constantly changing anyways....
Thanks Guys... It's alot to digest for novice like me... Just trying to get down to the nuts and bolts of Fuel Injection, I seen fully assembled Port Fuel Injection kits and have heard they do offer more HP, Driveability, and MPG, that's why I was considering doing the Q-jet conversion, because of the MPG I was getting, so in theory I assumsed it would get better mpg. However it sounds like a Frankenstein conversion with alot of tunning. But truely and honestly I remember reading here on this board one that was done, just can't seem to find it. With that said , Throttle Body Fuel Injection Kits like EZ-EFI,Holley EFI, and Atomic EFI by MSD... These seem awesome , easy to retrofit, and most claim driveability, and performance... but mpg seems to stand on the sideline in all the info.. not really mentioned there was an increase, or am I not reading between the right lines. My plans for my ride is to go the Pro-Touring route, so MPG and performance are my priorities, because I want to drive to the event drive and compete in the event and drive home. The biggest concern is cornering in the tight curves and the q-jet not being up to par and even on a hard launch or hard diving brakeing. So EFI of some sort has gotta happen. Likeing your input tho.:TU:
