carbs when there set up correctly work, what are your tricks to make them run like injection? i run my float level a little lower than stock(quadrajet), adjusted the stops on the float so it wont move around and regulate the fuel pressure down to 2psi. any other tricks? <IMG SRC="smilies/biggrin.gif" border="0">

Originally posted by FULLSIZE:
<STRONG>any other tricks? <IMG SRC="smilies/biggrin.gif" border="0"></STRONG>

Buy fuel injection!

<IMG SRC="smilies/thefinger.gif" border="0">

I don't think there is a way you can make a carb run "like" fuel injection. I would just install fuel injection and be done with it. You'll never go back to carb.

Charles

Originally posted by NECKSTER:
<STRONG>Buy fuel injection!

<IMG SRC="smilies/thefinger.gif" border="0"></STRONG>

You had to know that was comin', Fullsize <IMG SRC="smilies/laughing.gif" border="0">. I can't comment cause I'm spoiled by FI, but somebody here might post something useful, unlike our 3 responses <IMG SRC="smilies/biggrin.gif" border="0">

Jetting for the altitude you normally run around, but still isn't as good as FI.

I have an Edelbrock on my 302 that works great but nowhere near as good as EFI. I installed the off-road kit, lowered the floats, changed the jetting for the altitude and installed a fuel pressure regulator.

No.

Originally posted by FULLSIZE:
<STRONG>quadrajet <IMG SRC="smilies/biggrin.gif" border="0"></STRONG>
This is important; the Motorcraft 2100 is very good too, but other than those two, every carb I've ever seen sucks off-road, and unfortunately most people then draw the conclusion that EVERY carb sucks offroad, which just isn't so.

I like the foam floats, they have less momentum and don't bounce open easily - changing them before they soak up too much fuel is good too. On the two "good" carbs you can extend the float bowl vent tube(s) several inches, whatever you air cleaner will allow. You can pack them with coarse stainless steel wool to kill splash - pieces of a "chore-boy" kitchen scrubber are good for this. IMO, the problem with the spring-loaded needles is that they're not well damped and are prone to bounce on washboard-type surfaces; I don't use them, haven't seen much benefit. Q-jets have some openings in various places (depending on model) that allow dust, mud, etc. in, and it's good to seal these up with RTV. On 4MV's and similar (70xxxx series) Qjets, the secondary air valve blocking lever will flop back and lock out the secondaries on steep/rough hill climbs; take this off and thow it away, since the only purpose it ever served was to keep you out of the secondaries on a cold engine, and you should have enough sense to be able to handle that one yourself.

I have two EFI rigs and two carbed; a good carb (Qjet or 2100) set up properly will run at any angle rubber will contact something, and long after the oil pump starts to suck air or an automatic trans has run dry. I actually prefer the carb on a trail rig because if anything ever goes wrong it can be fixed with a screwdriver, and a little welding won't blow its mind. EFI does have an edge in fuel economy, and is the only way to go to keep proper stoichiometry going into a three-way cat (which is why you can't buy many new cars/trucks with carbs). If you're carburetor-impaired (flame suit on <IMG SRC="smilies/tongue.gif" border="0"> ) then EFI is certainly the way to go, but don't need to try to tell me that you can't get excellent off-road performance from a good carb.

Best carburator mod I know is to throw it in the trash where it belongs. If you must run a carb for some sentimental reason, then I agree w/the q-jet reccomendation.

Pete

carbs will never run like injection, but for all due purposes my carb runs til tires arent on the ground. engine knocking like a bitch, thats good enough for me. for every good example of a fuel injected rig out there, there are two really screwed up, every sensor unpluged, sputtering up the trail rigs. FI is great i'm sure, but you just havent given me any reasons to give up my carb just yet. <IMG SRC="smilies/thefinger.gif" border="0"> thanks for the support Llyod.

reasons to give up a carb:
Better power
more efficient fuel burning $$chaching
hands off tuning <IMG SRC="smilies/biggrin.gif" border="0">
no worries when changing altitudes
easy dianostic checking (just plug it in and see whats wrong)
you do not really need a big holly 950 cfm carm feeding a 700hp motor to crawl, so the need for big carbs is out.
no need for a choke on those cold arss mornings
If you go LT1 TPI you will get rid of your carb and distrib all in one swoop..
Thers a couple reasons I feel are worthy

No one has said anything about running their carb backward. A few in my club run 2 barrels backward and I've been told a q-jet will run at better angles if the carb is reversed. Any input???

I look at fuel injection as a safety issue. While there are some carbs that work very well, IMHO it cannot work as well as fuel injection. The time when you might need fuel injection the most is when you're on your side or pointing nearly straight up. It's is no brainer for me.... I've wheeled with a carb and I'll NEVER go back.

I'm with the rest of the carb guys, a well tuned motorcraft or quad will run anytime you need it. No it won't run on its side (well sometimes but thats just luck) but if your on your side your screwed anyway! yeah they lose a *Little* on fuel economy but I know of at least a few old carbed fullsized getting 15mpg around town, about the same as the good EFI trucks out there.

hey fullsize, I sent you a PM. check it!

Originally posted by FULLSIZE:
<STRONG>for every good example of a fuel injected rig out there, there are two really screwed up, every sensor unpluged, sputtering up the trail rigs. <IMG SRC="smilies/thefinger.gif" border="0"> thanks for the support Llyod.</STRONG>

And for every carbed trail rig that runs perfect there are a dozen that run like crap, and plenty more that drive good but will burn your eyes with how rich they run. I've yet to see a carb/independent distributor that can compensate for altitude and climate like an efi setup w/integrated distributor.

Pete

http://www.picturetrail.com/gallery/view?p=999&gid=244468&uid=121550&members=1

This should take you to a pic of, My carb with the bowl vents extended, I had a problem with the carb flooding at angles, also running electric pump w/pressure at4psi carb is weber 40mm.
All pro bumper pics also,Not happy with the bumper most of the holes didn't line up and chris didn't care. <IMG SRC="smilies/flipoff.gif" border="0">

thats nice. all of you who posted to go to fuel injection run chevys. i have a 360 dodge so my chioces for fuel injection are aftermarket or swap out my engine for a late model magnum mpi motor, which last time i ran across one was $2500 or more. thats why i say "yet" in my other post. i'm not going to give up my perfectly good running motor just yet. <IMG SRC="smilies/tongue.gif" border="0"> anything on that backwards Q-jet?

There's a guy running ARCA with a beaten old FSJ pickup, 401 and backwards Q-jet; and Lance posted something about one a while back (like maybe a year). I can't figure out what this does. Anyone?

BTT - someone that is running reversed carbs - give us info!!! <IMG SRC="smilies/biggrin.gif" border="0">

I have buddy that is running a backwards edelbrock on his 302 and it's as close efi as I've seen. It sat on it's top for an hour the other night and busted off as soon as it was on it's feet and it was still stading nose down. It will bobble a little going down steep grades, but works flawlessly going up or on it's side from what I've seen..

<IMG SRC="smilies/confused.gif" border="0"> may i ask, what is a reversed carb. I run quads but what is that <IMG SRC="smilies/shy.gif" border="0"> thanks

Reversed = mounted backwards. Must be a pain with a spreadbore, not to mention the throttle linkage. <IMG SRC="smilies/eek.gif" border="0"> Can someone explain how/why this would help enough to be worth all that bother?

BUMP for this thread on reversed q-jets... mine is pissing me off in inclines! What is needed besides a throttle linkage Where to get that?), more fuel line and vacuum hose?

Best carburator mod I know is to throw it in the trash where it belongs.

funny, that's where all of mine have ended up...

I run a Weber 38/38 on my FJ40 with elec pump reged to 3 PSI.
Seems to work great at all the angles I've been at:D
I have sat flopped on my side and finnally shut her off cuz I just couldn't get the tires to work :flipoff2:

Climbing and the plugs started and suceeded at fouling (oil) and the truck ran great other wise....


I have a FI setup but have stayed with the Weber cuz it just hasn't let me down....

Same reason I use a POINTS Mallory distributor....

Easy trail fix with a Gerber Multi-tool :flipoff2:


I think FI is great.....

But, I have not needed it yet.

Cory

motorcraft 2150 on my J10.... love it. it's never let me down yet

i'm switchin to a 4bbl next weekend, dunno how that's gonna work out on hills and such

Originally posted by FULLSIZE
thats nice. all of you who posted to go to fuel injection run chevys. i have a 360 dodge so my chioces for fuel injection are aftermarket or swap out my engine for a late model magnum mpi motor, which last time i ran across one was $2500 or more. thats why i say "yet" in my other post. i'm not going to give up my perfectly good running motor just yet. <IMG SRC="smilies/tongue.gif" border="0"> anything on that backwards Q-jet?

run chevy parts on the dodge. really. get a wiring harness, sensors and computer from a late 80's early 90's v6 grand am, then checkout www.diy-efi.com/gmecm for help modding the computer software. what the hell you might even get it to work :-)

no one has mentioned the new Holley Truck Avenger carb. I bought one but haven't tested it out yet.

Originally posted by FULLSIZE
i run my float level a little lower than stock(quadrajet),

I'd always heard because of the front-located jets on a q-jet, that you RAISE the float level... as opposed to lwoering it on a holley..

Does that mean if you turn the q-jet 180, you should lower the level?:confused:

i lowered it just a little bit, figured less gas to pour out of the vents. mines not backwards and it works great. i dont get the mileage the injected guys get but oh well, its what i have.:D

I just get problems when I'm on a steep hill for a while where the carb bowl dries up, and it won't run right again until I get it on flat ground...

Originally posted by Jimmy
reasons to give up a carb:
Better power
more efficient fuel burning $$chaching
hands off tuning <IMG SRC="smilies/biggrin.gif" border="0">
no worries when changing altitudes
easy dianostic checking (just plug it in and see whats wrong)
you do not really need a big holly 950 cfm carm feeding a 700hp motor to crawl, so the need for big carbs is out.
no need for a choke on those cold arss mornings
If you go LT1 TPI you will get rid of your carb and distrib all in one swoop..
Thers a couple reasons I feel are worthy

Reasons to give up fuel injection:
1) carbs are simple
2) no computer
3) no wiring
4) no crank sensor
5) no o2 sensors
6) when it stops working it's $35 to rebuild it or $250 for a new one
7) if your fuel pump dies you can use an oilcan and a piece of extra fuel line to get to out.
8) Don't need a EE to figure out why your motor isn't running
9) Retro is in
:D

Chuck P - 1 wire to the motor (HEI) and a Dualjet.

Originally posted by Lord Baskerville
I run a Weber 38/38 on my FJ40 with elec pump reged to 3 PSI.


Why do you run such a low fuel preasure? I've always been told you need 7 PSI at the carb inlet for best performance.

.\\arcus

my buddy put a wedge under his q-jet on his 87YJ

1/2" in the back and 1/8" in the front that way when going up hill the carb thinks it is level... it does fine on level ground the only time it does die is going downhill (wedge exagerates the angle) but while the rig is rolling it is easy to start

Originally posted by redruM
my buddy put a wedge under his q-jet on his 87YJ

1/2" in the back and 1/8" in the front that way when going up hill the carb thinks it is level...

Mine does act up going downhill, but gravity keeps the engine running, so I dont' mind that one bit...

Everything works fine, except on a steep uphill, so I don't see it needing a re-build (and dont' wanna mess something else up doing it)...

I guess having a locked, good-crawling rig exaggerates problems that most people won't see, since they won't get as up-angle as I would..

OTOH, I've heard it said that once the float is adjusted up, it will idle at up to a 45 degree angle... I know mine won't for very long, and if I get into the throttle, it will suck air...

reversing the carb would SURELY all but eliminate the problem, but I still am wanting to see what is required.. manifold is an edelbrock performer, and it won't be a problem turning the q-jet around on... Just wondering what the throttle cable I need is, and any other gotcha's with the process:confused: :confused:

I've not needed to try to turn mine around, and there's a short climb here that's well over 45 degrees in spots (a friend took an angle finder along). One thing that was discussed here previously is the void in the top plate of the carb above the float bowl, where the vent tube is. It's more pronounced on the older (70xxxxx series) quadrajets. On steep uphill angles this space is easily filled with the fuel from your float bowl, which exacerbates starving. Since the bowl volume is small, the effect of empty dead space is relatively large. Try taking an old foam float, shaping it to fit this space, and sticking it in place. You'll need to be sure that it doesn't interfere with the primary metering rods, and has a small vent hole to the tube (1/8" is plenty). Minimizing the dead volume in this part of the float bowl should help solve your problem (as will raising the float level some). Quadrajets already have a float bowl insert to fill the void in the bottom part of the casting; this (together with the tall vent tube) is largely responsible for their excellent offroad characteristics. Addressing the void in the lid should help, but obviously won't be as effective as mounting backwards. ;) I'm running an old iron Mopar intake with four holes (large and small) so no backwards mounting for me - at least not without quite a bit more work.

What about whene you get the computer to controll the timing with a knock sencer that pretty sweet

:question: i think your knock sensor isn't working:flipoff2:

Originally posted by FULLSIZE
:question: i think your knock sensor isn't working:flipoff2:

no no
no joke on some I think on later TBI ther is a knock sensor in the sid of the block that detects pining and adjusts the timing acordingly http://www.customefis.com/images/knock1.jpg

So Lloyd, since during my search I foudn you to be the q-jet god of the board... what would YOU do if you were in my situation...

It appears I could turn my carb around for nothing more than the cost of the throttle cable and a foot of fuel line..

I've yet to hear of any downsides to the reverse mounting of the q-jet, so I'm wondering...why not?

Mine's very basic.. no choke, only one or two vacuum lines (easily extended), no computer feedback stuff... Just the carb, throttle cable, and the vac lines, sitting on an open manifold...

Before i commit to it, have you ever heard of a reason why NOT to do it? I do like the foam idea, and it makes sense...but if turning it around really is as good as has been said (and logic says it would be), then why not do it?

Thanks!

I am no "god" by any stretch. Please don't call me that.

If I were in your situation I'd certainly try it. And probably keep it that way, too. When this thread came up earlier I was trolling for input from someone who'd done it. I think it should work just fine, and can't see anything that would be compromised at all, except pehaps behavior in a steep nose-down attitude, and we all know how important that is. :rolleyes: Assuming, of course, that the secondaries actually do clear the manifold walls; and if not there's always a custom spacer. I would've already tried it, but with the manifold I've got it's pretty much impossible (would work with a spacer but kill airflow) until I bolt the intake to a Bridgeport and "fix" it for this purpose, and then I'd need to fab a more complex throttle pressure linkage for the 727. I'd like to hear from someone who's done it before going to all that trouble.

Foam in the top plate is good, and picking through all the different float styles to find one that you like and fills the bowl well is good too; but the principal drawback of all this is that the jets and rods are still in the front of the bowl, and there will always be voids around this stuffing for fuel to get into and let the top get dry. Also with the carb mounted normally there's the fact that at a steep enough angle fuel will run out the vent tube. Turning it around seems to be the only logical way to completely eliminate this problem (or at least move to to a situation where throttle response is a lot less critical). If you get steep enough with a backwards mounted carb that fuel runs out the vent tube, it just goes into the air cleaner, not the primaries.
If you like the way it works, I may do it to mine too. :)

OK, I won't stroke your ego... "Lloyd, the knowledgable q-jet guy"...how's that.

I'm gonna go hunting when I get back from this trip for a throttle cable that will wrap around to the other side of the engine bay... We have ZILCH for pick-n-pull's around here, so I'm gonna have to go in the back of the auto parts store and hunt around. They're used to me doing that now.. :D

One last Q for ya... what should be a general torque to bolt the q-jet down to the intake? I read alot of warnings on that, of course it was AFTer I've removed the carb 2-3 times already, and put the bolts back on kinda snug... Hope she ain't warped!

I really doubt you've warped it - "kinda snug" is about right. Putting the wrench here in my lab in the vise, I get something on the order of 50-60 lbs/in for the "feel" I like. What's more important to preventing warping than the final torque value is to make sure it sits down flat and is torqued evenly. However, if you're slow and careful and torque 'em really f***ing tight, the different thermal expansion coefficients between the zinc casting and steel bolt can crack the carb casting when it gets hot. Originally they came with long flathead screws in the front to limit how hard you could pull them down (using a screwdriver) without having to go to get a screwdriver-blade socket and longer lever. If you limit yourself to a screwdriver-type tool with a handle diameter of 1-1/2" or so maximum, twist hard on it and it'll be just right. If you go to a much longer lever like an end wrench, ratchet handle or breaker bar, be gentle. :)

I thought the q-jet needed 7 psi at the carb?? Is there an advantage to running with less??

I had always heard much less...something like 2.5-4psi...

Less pressure is better. More volume. Bouncing and general offroad treatment, with higher fuel pressures, tends to force the float down into the fuel more. When the fuel and float bounces, higher pressures also shoot big globs of fuel into the float bowl, and just keeps jacking up the fuel level in the bowl. Since Qjets have a notoriously small bowl, people often run the pressure up to keep them from starving at WOT. But, if you have a good high volume mechanical pump (one of the things Carter was good at) or augment your mechanical with a good electric (I like redundancy; have a mechanical with an old Bendix Elmira electric back by the tank) you'll get plenty of fuel even at 2 psi.

chevy vans have VERY long accelerator cables!

might check out the Astro van cables too.

matt

Thanks Matt!

Forget using a carb made for a car (cars run on level ground)
carters, holley, quads all of them are designed to work on flat ground with the occasional g-force and or incline factor.

Mikuni carbs are super simple and will run at any angle they are easy to mount ,install, repair, rebuild, test, sync. The only real issue is air cleaners and filter boxs. belive it or not mulitple carbs are not difficult to adjust or sync. carb adapters are not even that hard to make, using carbon fiber material. Currently I am building a set of 4 - 45mm carbs for my jeep, I am working out the linkagae for staging the carbs (this IS the hardest part)

I would run a carb.... ON my lawn mower!!!!!! :flipoff2: :D :flipoff2:
carbs suck monkey ass:barf:

I have a Weber 32/36 on a Toyota 22R. When I added the header there was a spot for an O2 sensor. Since there was a spot for it, I added one and ordered a fuel mixture meter from Westach. I haven't got the meter yet but when I do, I should be able to check the mixture and adjust the jets accordingly. I live a sea level (Seattle) but hop east over the mountains frequently. Hopefully by monitoring the mixture on trips I'll be able to get a happy medium by adjusting pieces with the jet kit I bought.

Originally posted by Scrambler


Why do you run such a low fuel preasure? I've always been told you need 7 PSI at the carb inlet for best performance.

.\\arcus

I run 3 PSI cuz it works...:D
7 PSI is probably for max perf. in high rev situation or daily drives.
I trailer.......
For the street I would probably turn it up, but, have not ever needed to.

Also, seems to act like a rev limiter as I will starve for fuel if i hold at 6K or more.
This is probably VERY good as the 2F should think about coming apart at those revs:rasta:

But, I build good engines:emb:

Cory

Lloyd, this is mostly to you... Did the reversal yesterday... Bought a Spectre (the blister-packed crap) spacer/adapter from the local hi-po shop, the only long throttle cable the parts place had for a chebby (WAY long, but who cares), and 3 feet of fuel line.

I got the FJ as steep up as I could before I broke it, and it idled, and revved fine... perfectly, in fact. The secondaries didn't like it, but they are now starving for fuel, but I don't go WOT on hills..

All isn't roses, though, but some trimming with the dremel on the adapter might help...

Because of the spacer/adapter and manifold not being a perfect square or rectangle (its wider where the secondaries are), there's now some dead space where the air can tumble before getting into the manifold I think, which causes WOT to run funny in first gear (sometimes in second) (kinda a bog, go, bog, go), and on the road, I can get a stumble as I just crack the throttle open...didn't manifest itself off road at all though, and pulled cleanly from 450-500rpm.

Mind you, my carb is NOT new, so it may have some problems of its own, but I'm convinced that the reversing WORKS! That was right before I tried an obstacle I've tried many times before and broke a Birfield:nuke: ..oh well.

Once I fix my junk and get it on a real trail (I broke it in my little playground behind the house), I'll know for sure how well the carb works... I'm going to be grinding on the adapter to try and smooth out the airflow as well.

You did it! Cool. I think that the WOT stumble on road you described is a symptom of the same effect you see on hills; the secondaries feed out of the back of the float bowl. On pavement you can pull enough forward G's to starve them, which makes it sputter and lets fuel slosh back to the feed ports again, etc. No surprise there. A while back Mike posted photos of his custom adapter (upside down square to spreadbore) that he worked over with a die grinder; it looks good and might be worth finding. I'd love to hear how you like it on an extended trail test. Thanks a bunch, man! :beer:

Good point... I lowered my float level when I flipped the carb, since raising it was for a normal-mounted carb... Maybe I shouldn't have messed with the level?

Should I extend the float bowl vent with some tube and raise the float level back up? Whaddya think?

I'll try searching for Mike's pics... is that his username?

Yeah, I'd try bringing the level back up. That'll probably help. Extending the vent tube never hurts either. Here's that thread with the pic of Mike's adapter: http://www.pirate4x4.com/forum/showthread.php?s=&threadid=38033&highlight=qjet

Aaaahh, nice job he did there...

I got a spreadbore adapter... it's to mount a Holly, edelbrock, etc.. on a q-jet manifold I think... it's the one pictured here:
http://www.mascotgraphics.com/adapter.JPG

Had to do a bit of creative hardware work to get it on, but it's OK...

If you're looking at the picture, the primary openings on the adapter go into the manifold, and the manifold is quite a bit bigger at that point (since it's big enough for the secondaries), so I think opening it up to match the manifold will work there..

And, on the secondaries... Probably not a whole lot I can do there, since I don't want to cut the manifold. Maybe just try and shape the metal to allow for smoother airflow.

Think I can use a dremel for this? If so, what type of bit? I've got a dremel, 4.5" grinder, and some small hand files to use... Hoping not o have to buy more tools (cash is way tight), and I can get the G/F to hold the shop vac to keep the nasty bits out of the engine when working on the manifold...

Do I see a gap between the manifold and plate on the right side of the photo, on the secondaries? Maybe it''s just something in the photo, but it looks like one. A Dremel will get you there, but take a bit longer than a die grinder. I really like carbide cutters; they cost a little more initially, but by the time you've burned up a few of the cheaper ones the carbide ends up being quite a bit cheaper.

ToyFamily got their's to run at damn near any angle..granted that's a 2bbl yota carb but the same tricks could probably be adapted on a 4bbl.
send ToyFamily a PM, see what they say.

Lloyd, I actually used that photo just to show the spacer, not the manifold... My manifold is not a 4 hole deal (squarebore?) like that.. it's a spreadbore. I can get in there and take a picture when I pull the carb, but my front axle is on jackstands right now, and I hate climbing around on a vehicle while it's on a stand.

Unfortunately, for the die grinder, I don't have air... But I would be able to swallow a carbide cutting bit for the dremel.

Thinking about this (and looking at the photo), Lloyd.. if you didn't mind cutting your stock intake manifold, or at least enlarging the holes in the manifold for the primaries, I think you could use the same adapter I did and reverse yours! :smokin:

For lowtorious, each carb has their own idiosyncrasies(sp?), and so far, I'm very pleased with a reversed q-jet...

No need to photograph it, I know which manifold you're talking about. It's what I thought you'd said from earlier, I was just surprised to see the 4-hole in the photo. Carbide cutter for the dremel to remove most of the material, and then one of those little drum sander tools to smooth it all out and make it look good. I'm going to have to think through this throttle pressure linkage for the 727 now....

Welp, could not find a carbide cutter... so out came the reinforced cutoff wheel, the 4.5" grinder, and a whole string of expletives. actually got it cleaned up and looking OK! there should be no more tumbling air...

What looks like gaps really aren't, and the sharp edges on teh top of the adapter sit under a gasket.. flow areas are rounded. it ain't pretty, but it'll work! (hopefully!)

http://www.nctacomas.com/eskimo/carbspacer1.jpg
http://www.nctacomas.com/eskimo/carbspacer2.jpg

Also found that I made a bone-headed move when I changed the spark plugs, and gapped them WAY to small.. I should know by heart now that a Chevy HEI calls for a .055" gap!!!:mad:

STILL haven't got to properly test it... inner axle shaft issues, and I'm going to Tellico next week with 4-5 new mods that have yet to be tested, (like the carb, for example!) I don't have a warm fuzzy, but everything *should* work!

TTT for Lloyd to see the pics.

Thanks for posting those, Eskimo. It looks like it should work really well!

My carb.

http://www.pirate4x4.com/forum/showthread.php?s=&threadid=75769

Are those second 2 pics pics of the first pic after cutting out the holes?

J. J.

No, it's just a different angle...