Hey guys I was just looking for some help with carbs. I know there have prob been quite a few other posts like this one but your help is appreciated.

I have a Jeep CJ7, with a crate vortec 330 deluxe, with a turbo 350 with a slightly higher then stock stall about 1900rpm, with 3.73s. It currently has a Holley 600cfm vacuum secondary carb that is needing some help. I am looking at getting a new carb.

I have been looking into the holley truck avenger 670 and was wondering how it compairs to other CARBS, now i know its not going to be as good as injection but I dont have the money to do this. The jeep is primarly driven on street, some off road, snow, and sand dunes, as well as occasional drag race.

Which carb would you guys reccomend for best all around performance as well as ecconomy (if at all possible) with gas prices the way they are. I currently only get about 9mpg with a mixture of highway and city.

Any help is appreciated thanks a lot.

Put a Quadrajet on it.. I have a couple of friends with the truck avenger and I am not impressed and they are not either..
Quatdrajet is simple and reliable.
Not bad on milage if you keep your foot out of the secondaries..

Use junkyard parts and go efi.

Same price if not cheaper than a new carb.

I got a 670 TA on my 454, and the second one I put on there works great.
The first one was a POS.

a vortec 330? is that 330 CI? i think a 670 is a little large for that.

No its a 350ci, sorry about that, they just call it the 330 deluxe crate motor cause its rated at 330hp. I was looking into possibly getting a truck avenger.

Fuel injection would be nice but seems expensive, even if i got junkyard parts wouldn't it still end up being more by the time you get the computer and harness? What type of fuel injection are you talking about MPI or TBI or what?

Thanks for the input guys.

I've got a Holley Truck Avenger 670 on top of a 300hp 327. Works great for me.

It was a little tough to tune the idle not to be so rich, but once I got the timing, mix screws set, she'll run at some amazing angles for a carb.

I like Q-jets too, but finding a good one these days if difficult. :flipoff2:

I've got a 750 vac secondary truck avenger on my 383, works great ;)

I'm far from a tuning genious, I just got it out of the box, bolted it on, set the floats and it works.

Fuel injection would be nice but seems expensive, even if i got junkyard parts wouldn't it still end up being more by the time you get the computer and harness? What type of fuel injection are you talking about MPI or TBI or what?


TBI is going to be the simplest way to go. Go to the JY and pull EVERYTHING including the harness and cpu. Its gonna take a while to pull but you will be happy.

I have a 670 Truck Avenger and I was happy with it on my maiden voyage. I didn't tune it at all, installed and set the idle speed. It works better than the old q-jet I used to have. The same angles that would flood out my qjet have no effect on the holley.

But you are right, it is not FI. It still has it's limits. It crapped out on me on a few steep ascents (well over 45*, more like 70* on white knuckle hill it died) but never on any descents. I am going to have it tuned and see if that helps.

look for a 90's grand am with a v6. the computer can be programed with a AUJP chip for a 350... seach there is lots info posted here.

Im running an 800 double pumper (list 4780) on my daily driver 350.

its not too big, either. throttle response is twice what the 600 cfm vac secondary (list 1850) was..

if someone is telling you that a 670 is too big, then they just need to realize that they are limiting fuel mileage by making the carb richer with the smaller venturi pulling more fuel over...the same jets in a larger carb wont use as much fuel because it wont have as much signal. makes for a softer bottom end, but a lot more response in the cruise rpm, where the smaller carbs suck.

I have the truck avenger on my 350, same horsepower rating as yours. bolted it on, set the idle, floats and electric choke and have not messed with it for years. it only stalls on really steep descents, you have to have the truck pointed at the ground. I had a quadrajet before that and it would stall on any descent.

Use junkyard parts and go efi.

Same price if not cheaper than a new carb.

I know you said you want to go carb for $$ reasons, but I agree with this quote. Been there done that! Go EFI, better power and fuel milage.

Go EFI, better power and fuel milage.

not true.

maybe the fuel mileage part...

Definitely NOT the power part.

Can it get close? yes. getting close is spendy. carbs arent as spendy for being more powerful.

Sure, a carb wont run upside down. Generally, your tires arent touching anything when youre upside down, anyway, so that probably wont help ya.

Even the drag race guys know this. You think they would run a carb if it could be outperformed?

Thanks for all the input guys, I really appreciate it. So what is the lowest anyone knows a new 670 truck avenger going for (and where) the lowest i have found reciently is 400.

So one other thing i forgot about, the mpg about 9mpg in a jeep with the mild 350, does it seem about like what it should be getting? What do some of you guys get? Any advice on tuning my carb for better ecconomy or is that about what i should be accepting?

Thanks a lot for all the help guys.

My bet is on EFI but you have to reprogram it to make it have OMG WOW performance. Due to the complexity learning how to use all the computerized tools, wideband 02, etc, it is a lot to ask for some (me included to some extent). Most people get it running and leave it at that never knowing how very, very flexible, tunable and reliable EFI is.

The second best choice is the trusty old quadrajet IF you don't mind a fairly steep learning and high parts expense ($200 in parts) to tune it. I have collected some very good documentation and have it posted HERE (http://www.florida4x4.com/tech/quadrajet/). If you decide to go this route then be sure NOT to buy anything that was remanufactured. Try to get a vintage edelbrock 1904 (350ci), 1906 (454ci) or 1910 (race). If searching the JY look for big block caddy's and later model trucks. Get the specs on the carb number and be sure before you try to tune that you verify the needles and jets are what the OEM specified. If you try to tune with ANYTHING other than the original calibration, you're bound to find only frustration unless you're VERY lucky.

Read and understand the instructions at my link you can tune it to do anything.

If you are planning on around 400, then you can get a complete tpi from the 85 to 92 vets commaros and firebirds for about 400. That will get you every thing you need and if you get the MAS system there wont be any need to program it.

Skeeter

Offroad is no place for a MAF. IMHO. Get a TBI from a late 80's truck or TPI from a 90-92 camaro. The later TPI does not have the 9th injector to fool with and is very durable with the SD (speed density) sensor only. Yeah you gotta tune (or build the engine like a stock GTA transam) it but damn it will rock. The "best" TPI chip for any hot rod project with an auto is PN 16151348.

all i have to sya is do not use a quardajunk, i had one specially built to my engine specs and i thought it ran ok maybe a little slugish, then i got a 670 truck venger and it felt like i gained about 100 hp, i coudl not be happier with it. and for the price you cant beat it, and setting up a holly is so easy.

i have one its a 750 just about brand new, probly (mayeb ) 100 miles on it. blue printed carb

not true.

maybe the fuel mileage part...

Definitely NOT the power part.

Can it get close? yes. getting close is spendy. carbs arent as spendy for being more powerful.

Sure, a carb wont run upside down. Generally, your tires arent touching anything when youre upside down, anyway, so that probably wont help ya.

Even the drag race guys know this. You think they would run a carb if it could be outperformed?

Okay, I'll agree with you on one point. All out WOT a carb can outperform an EFI system. Just so you know an EFI system will not run upside down, the fuel pick up tube runs dry upside down, you need propane for upside down. EFI will run at any angle as long as there is fuel at the pick up tube. I owned a quadrajet and a Holley truck avenger. I didn't care for the truck avenger at all. I change altitude wheelin to much to bother with constant holley carb tuning. I noticed that once I went to GM factory TBI on my modified 350 with a custom prom, both my milage and power went up. Not the best carb tuner in the world and I know that is the main reason but IMO on average with offroading EFI is the ONLY way to go. Can't really apply drag racing to offroading. It's like comparing apples to oranges. But I do understand you point of view. Just sharing my point of view.

Yep that's right all. EFI don't make as much power as a carb (NOT (http://www.gmhightechperformance.com/features/0507htp_2002_pontiac_trans_am_feature/)).

I think the main reason anyone runs a carb in drag racing is the rules. Think about it. You have sophisticated electronics that take thousands of measurements per second on a variety of inputs such as Barometric pressure, fuel pressure, Intake air temp, detonation, MAP, O2, knock sensors, etc and then looks up fuel and timing values, averages everything to create the perfect mixture of air, fuel and spark. The ONLY limitation to what EFI can do is solely based on the knowlege and capabilities of the tuner and the power of the computer. How do you think those 6 second 200 mph + single turbo Mustangs get down the track time and time again. With a demon or holley? Damn thing would blow up more than it would cross the 60 foot mark!

EFI is here to stay and will only get better. The fact that the late 80's GM stuff works so well is a testimony to that. It's PERFECT for the off roader because it is cheap and reliable. You just need to invest a little time to learn how to wire it up and what you need to adjust things in software.

Forget EFI with all the stupid programmers, chips and expenses dude!
Stupid chips and computers trying to do all the thinking and tuning for you.
Leave the computer at the office where it belongs!
I've got a Holley 750 double pumper on my 350. Like someone else said, a little softer on the low end but when it comes to mid range and high end - look out! A lot less expense and a lot more options for high performance builds! :flipoff2:
"The only limitation to what EFI can do" is how much money you have in your wallet! Peddle that crap somewhere else!

Forget EFI with all the stupid programmers, chips and expenses dude!
Stupid chips and computers trying to do all the thinking and tuning for you.
Leave the computer at the office where it belongs!
I've got a Holley 750 double pumper on my 350. Like someone else said, a little softer on the low end but when it comes to mid range and high end - look out! A lot less expense and a lot more options for high performance builds! :flipoff2:
"The only limitation to what EFI can do" is how much money you have in your wallet! Peddle that crap somewhere else!


well said!

for the SAME power output:

EFI=cubic dollars and your own mechanic on staff with a computer to help him....

carb=cheap, and repairable on the trail.

EFI is only difficult for mentally challenged hillbillies. there are so many resources out there its not even funny. if you cant learn how to deal with EFI its because your either too fucking lazy or too stupid.

EFI is only difficult for mentally challenged hillbillies. there are so many resources out there its not even funny. if you cant learn how to deal with EFI its because your either too fucking lazy or too stupid.

lmfao, big man.

The best carb is a propane carb. Best of all worlds for an offroad vehicle. :smokin:

Well there's no need to be a dick about it, odin. EFI is cool, complicated and too much trouble for some. So what? Nothing beats a carb for and ease of installation and reliability (especially after the EMP bomb but I'm sure we'll be worried about other things after that!). Once you take a drill to a carb to change the metering and go too far you'll really appreciate that a EFI system can go back with a simple software change rather than machining new idle tubes and pressing them into the carb body.

The computer doesn't "think for you" as someone said. It does the work you ask it to do. Garbage in, Garbage out. Good tune in, high power and fuel milege out. Given a choice I'd run EFI over anything.

My standard Holley wouldn't run on extreme uphill angles. I had a problem with my Quadrajet running on extreme down hill angles. I switched to a Truck Avenger and it worked great up, down and on it's left side. I finally went to FI because the truck wouldn't run like this:

Fuel in the pick-up but not a whole lot of oil pressure (well none actually.:D )

http://fourdice4x4.com/photos/albums/pebbles/moonrocks2006_0902_017.sized.jpg

I still feel that carbs are great as long as you don't want to run the thing on a 90 degree angle.

Gee, too bad you didn't post a little sooner. I just sold my Truck Avenger for $150!

Well there's no need to be a dick about it, odin.

I thought he was gonna be standin in my driveway ready to whoop my ass.

No he's sitting at the keyboard spanking his meat :grinpimp:

not being a dick about it. get sick of hearing everyone say its junk simply because "they know nothing about it". its not that hard to deal with. if you want to build a good cage for your rig and dont really know what your doing, what do you do? you come on here research it. get info from different sources and figure it out. its NOT that complicated. there are TONS of books on how to do it. it doesnt cost a shitload of money like alot of carb owners want you to believe either. most systems can be put together with simple junk yard parts. you just need to know what to look for. back to the research. about the only thing you really need to do is have a chip burned for it. for what 100$ whoa break the bank.

and A LOT of the big name drag racers do use FI. now what they use IS very expensive. but your also talking about 1500+ HP. and the FI isnt that much compared to what they have into the motors and cars anyways.

Im running an 800 double pumper (list 4780) on my daily driver 350.

its not too big, either. throttle response is twice what the 600 cfm vac secondary (list 1850) was...apples and oranges:shaking: read that in a book?:flipoff2: just friendly ribbing

if someone is telling you that a 670 is too big, then they just need to realize that they are limiting fuel mileage by making the carb richer with the smaller venturi pulling more fuel over...the same jets in a larger carb wont use as much fuel because it wont have as much signal. makes for a softer bottom end, but a lot more response in the cruise rpm, where the smaller carbs suck.
Smaller venturi's requires smaller jets. Smaller venturi's are going to give a higher vacuum signal to the fuel ports. Going to be more sensetive and therefore meter fuel better. Only reason to use a bigger carb would be WOT and peak hp.

apples and oranges:shaking:

Where did I hear that before........:flipoff2:

BTW: I probably got as much into my TBI as some have into their carb. Closed loop operation with an $80 custom chip and I have zero tuning and turn key starts.

I got a brand new 670 Truck Avenger carb and it fuckin sucks!:flipoff2:
I've got a stock quadrajet on there now and shes runnin like a charm!:D

Best Thread Evar! (TM)

Where did I hear that before........:flipoff2:

BTW: I probably got as much into my TBI as some have into their carb. Closed loop operation with an $80 custom chip and I have zero tuning and turn key starts.
a fruit stand? a grocery list? ingrediants for a fruit salad.
kudos to you, must be in that gray area in my memory between short term and long term memory.

I run a 670 on my BB
I had a carter AFB on there before and wow was it CRAP.

I have yet to stall out my TA but I have made it stumble a few times, mostly on descents. Either I have never had the balls to climb a steep enough grade or just havnt found one to stall out the TA but I am just tickled pink with it.
I have been almost completly on my side, like the pic a few posts above and the carb just idled away. I think for the bang for your buck and simplicity of it, it is the best way to go.

I run it like it came out of the box. It does run a bit rich and one of these days when I am bored I will fix it but other than that, it is a great carb.
I bought it at Summit in Ohio for a bit more than $425 IIRC so I think $400 for the carb would be a decent price.

not being a dick about it. get sick of hearing everyone say its junk simply because "they know nothing about it". its not that hard to deal with. if you want to build a good cage for your rig and dont really know what your doing, what do you do? you come on here research it. get info from different sources and figure it out. its NOT that complicated. there are TONS of books on how to do it. it doesnt cost a shitload of money like alot of carb owners want you to believe either. most systems can be put together with simple junk yard parts. you just need to know what to look for. back to the research. about the only thing you really need to do is have a chip burned for it. for what 100$ whoa break the bank.

and A LOT of the big name drag racers do use FI. now what they use IS very expensive. but your also talking about 1500+ HP. and the FI isnt that much compared to what they have into the motors and cars anyways.

ahhh, not being a dick about it, but youre calling me stupid?

as for researching it, I wouldnt do it on here. I would go to www.megasquirt.com if I wanted to get info on EFI. At least I can trust that info. Do I know nothing about it? you tell me. You seem to be the expert, here, right? I only work here part time. As a matter of fact, I havent been paid yet....

what qualifies you to call anyone stupid? do you give IQ tests for a living?

Ask Troy Patterson what he thinks of EFI. know who he is? www.tmpcarbs.net Nice guy, too.

Why dont you ease up a bit, big boy? Being so negative will get you nothing but grief.

i wasnt directing my statement of stupidity towards you. if you feel i was then sorry. and I also think there are much better resources for EFI info than PBB. just stating that there were MANY. and there seems to be a few people on here with some good experience with EFI. hell im not even saying someone should use it. its like anything. it has its advantages and disadvantages. it has its place. i chose to run propane on mine. I was only trying to state its not as difficult as it seems.

do i know who troy patterson is? no. do i care what he thinks of EFI? no. its his opinion. hes entiteled to it. and im sure hes a nice guy.
its like peoples opinion on holley versus edelbrock versus quadrajets.

edit: i went to the megasquirt.com link and it didnt seem to take me to anything useful on EFI. is the link working?

You mean PBB isnt the end all be all of EFI knowledge?
My world is crashing down around me!

i wasnt directing my statement of stupidity towards you. if you feel i was then sorry. and I also think there are much better resources for EFI info than PBB. just stating that there were MANY. and there seems to be a few people on here with some good experience with EFI. hell im not even saying someone should use it. its like anything. it has its advantages and disadvantages. it has its place. i chose to run propane on mine. I was only trying to state its not as difficult as it seems.

do i know who troy patterson is? no. do i care what he thinks of EFI? no. its his opinion. hes entiteled to it. and im sure hes a nice guy.
its like peoples opinion on holley versus edelbrock versus quadrajets.

edit: i went to the megasquirt.com link and it didnt seem to take me to anything useful on EFI. is the link working?

woops, screwed up the linky....

http://www.megasquirt.info/

has a lot of info. more than i care to read tonight :D
but why go through all the trouble to build your own computer when a factory one can be modified much easier to suit most peoples needs.

why build your own controller? so that YOU have control of all the circuits instead of having to rely on someone else to reprogram your ECM.

I've built three M'squirts. Though maybe not so easy, but definately more rewarding. Plus now they can do ignition as well as FI. Nothing like tuning the advance curve to match the motor and fuel curve!

The free software is enough to warrant the megasquirt but if you know the vehicle to rob you can get a corvette style "water proof" computer. Only a few cars we're designed with this. The reason is that the computer is put in the wheelwell exposed to elements. Regarding the water proofness, who really knows. I doubt that it will survive total submersion for a long period of time but it is better than no waterproofing with a regular style computer. Make sure you use all weatherpack connectors and the OEM stuff if bullet proof.

why build your own controller? so that YOU have control of all the circuits instead of having to rely on someone else to reprogram your ECM.

I've built three M'squirts. Though maybe not so easy, but definately more rewarding. Plus now they can do ignition as well as FI. Nothing like tuning the advance curve to match the motor and fuel curve!

out of curiousity though, what kinda money are we talking to build and run this megasquirt?