Dabesiv

iTrader: (1)

I have the 4 barrel CC Qjet and it has treated me fairly well once I found someone who can tune it right.
It is supposed to get better MPG's than say an edlebrock, but at 10-12 MPG's for me I can't imagine it gets much worse. I have a ton of modifications I would love to do on my car but each one has a big problem with a CC carb ( MSD box and distributor come to mind). I have to wonder if it is worth keeping it on.
I know when I first joined thirdgen.org I asked the same question and Five7Kid did an awesome job of convincing me to keep it haha. But I managed to get back in that mindset.
Does anyone know of a way to make said mods work with a CC qjet or am I looking at ditching the carb for now?

kmcn47

what i'd like to know is why bother with the msd ignition stuff when it isn't really needed? the factory hei system is fine, alot of guys are making good power with factory ignition setups

Dabesiv

iTrader: (1)

It probably isn't required, I am just not seeing much performance out of what I currently have and it seemed like an easy fix to help some. I have a thread in the engine section for that exact problem of having no real big gains in performance.

kmcn47

to be honest your not gonna get much performance out of your stock engine, i see that you have a "GM crate motor" if its the 350 "direct replacement" crate motor its more or less a 70s smog motor 350, probably a little less power then your 305 had the main performance killer is the heads, you could port them or just get better ones, but as far as your ign system when was the last time you got a new cap/rotor/plugs/wires? if its not performing, hard starting and missing, it could be time, also look at a new coil and maybe even a new module, i did the like to my car and it fires up on the first turn of the key, my problem is my carb, the choke needs set and i need to do the jb weld fix to its leaking gas

Dabesiv

iTrader: (1)

I was told the Goodwrench 350 was supposed to be a little beefier with its performance than a regular 350, granted this was a few years back when I was too dumb to ask many questions about these things. I know it is more powerful than the 305, you can feel it without a doubt. plugs and wires last year and new cap and rotor as of yesterday haha will be testing it out tomorrow afternoon see if it helps and will post if things have changed, as I was misfiring a lot the past week.
This carb has been a pain to find someone that knows what they are doing to repair it and tune it properly, took me 4 years and a dozen mechanics to find a guy an hour away that does it perfectly, so good luck there.

devestator_x

iTrader: (1)

Would jumping from a 305 to a 350 really make a huge difference in MPGs? I see you're getting 10-12. I've got an original 305 in mine with the stock carb and Im getting 16.1 on average in stop and go traffic every day. I read a Motor Trend article that tested the 1983 305 HO with a 5 speed and it was advertised by GM at having 16-17 mpg and tested at 14.

Could there be other underlying problems that are causing the lack in power and poor gas milage?

kmcn47

i'm thinking the carb, when was it last rebuilt?

Dabesiv

iTrader: (1)

Yeah, I got around 16 to the gallon with my 305 and it was amazing compared to this. Granted I had a few things working against me when I last did my mileage including running rich for winter, misfiring, and a serious lead foot. There are plenty of bro-mobiles aka Subarus around here that like to show off and I like to keep them in line haha. I'll do a new test this week with me running lean and the distributor, but I don't expect more than 12. It seems to be a general thing that the more CI's the less MPG's.

Dabesiv

iTrader: (1)

last rebuilt maybe a year and ago, just tuned yesterday, and I am very vigilant about cleaning it every few months, so I shouldn't have many problems with it. It sounds great besides the clicking but I've always had that.

gearhead141

I own an '85 T/A with the LG4 and a CC Qjet. The engine is completely stock, meaning stock air cleaner and exhaust manifolds. I run regular fuel and have a 22 mile trip to my job. I am routinely getting 21 mpg. This is running at a little over 2k rpm at 70 mph. The 305 has just over 60k miles on it so it has a lot of life left in it. I am going to stick with the Qjet as I don't think any other carb is going to perform that well. I did replace the O2 sensor in the driver's side exhaust manifold after I first got the car. I've run a bottle of fuel system cleaner through it just to make sure all the ports are clean in the carb, but other than that I've just driven it. I can get 270 to 280 miles out of a tank and then the refill is about 12.5 to 13 gallons. Who would have thought that a 1985 car with a V8 and automatic could get such good mileage!

Keep the CC Qjet. You won't be sorry.

Dabesiv

iTrader: (1)

I wish I could be so lucky haha. I think I have a dented tank as I only get 11.5 gallons full and with a 3 speed auto I'm around 4000-4500 rpms at 65 which kills on a 52 mile round trip to work. My 305 made it to 250, 000 miles before it took a dirt nap so you have got a long time with that thing.

blue85305

You've got 3.23s still? You shouldn't be turning anywhere near 4000 rpm at 65. My 84 with a turbo 350 turns about 2800 at 65. Regardless 10-12 out of a stock engine is ridiculous.

naf

iTrader: (7)

Your 200 should be a four speed auto. Are you really turning 4000+ at 65? Tach errors are common.

My 85 with a 350 (LO5 cam) averages a hair better than 20. My 87 with a lot more cam still gets close to 20. You've got some issues that need resolution. What resources do you have on-hand? Timing light, volt meter or dwell meter? You need to ensure your motor is going into closed loop.

Clicking is normal. It's the Mixture Control Solenoid (MCS) within the carb. It adjusts the primary mixture based on input from sensors. If something's off adjustment or a sensor is bad it will stay in open loop, warm up mode or limp home mode and you'll see the mileage you're getting.

Rolling resistance will also affect mileage. Alignment, tire pressure, good wheel bearings, etc. But focus on that CCC-Qjet system. I think you'll find some mileage and performance there.

Dabesiv

iTrader: (1)

I haven't made any mods to the back end, I'm terrified to get any less MPGs with doing a 3.73 like I would love to have. I'll double check the RPMs later tonight or tomorrow but I am fairly sure its at 4000, It freaks me out, I know that I'm at about 5500 at 100 MPH and have only ventured higher than that once and it freaked me out running in the red.

blue85305

Stock tachs in these cars were notorious for being off, I use a sun pro tach. Does it sound like you're turning that high.

Dabesiv

iTrader: (1)

The 2004r is a 4 speed auto, but this is the 200c which was like the smaller and weaker version of the th350, plus the shfter only has 3 speeds 1,2, and D without a circle around it like the overdrives do. I am very positive it is only a 3 speed.

I have very basic tools for the big things. Tons of sockets etc. but no timing light and fancy tools haha. I am just starting off at getting into car repairs, so in time I will.

The clicking I discovered last night is from a manifold leak, I knew it wasn't the carb as it is much louder, I was praying it wasn't a lifter so I did the screwdriver test with no sounds and then a buddy checked it and said he had the same sound with his '86 and it was a manifold leak.

The alignment might be a bit off, but the bearings are about 2-3 years old and I keep my preasure at or above 35 PSI all the time.

Next time it's in the shop I can ask them to take a look at the open loop stuff as I would have no clue what I am doing.

kmcn47

at any rate get a tach any cheapo will do and see what your really doing, my stock tach reads 6500 at 55 i know damn well they're almost all wrong, in fact i remember reading somewhere that none of the factory tachs pre 90-91 are accurate i think theyre all broken

Dabesiv

iTrader: (1)

Maybe once I have some money not getting stolen every other way from this car I will haha. I was wrong about my tach though, it is at 3500 for 65mph, still high, but not as bad.

Street Lethal

iTrader: (16)

Tuning a carb is the same as tuning EFI, it is just more of a mechanical process than it is technological. If your serious about keeping your carb, and are serious in wanting to tune it the right way, well then you need to take the guess work out of it. Plug an air/fuel gauge in the exhaust stream and see what your a/f ratio is during idle, part throttle and wide open throttle. See what your engine likes, then make the necessary adjustments to keep it there. Then, work on your secondaries and acceleration enrichment. Finally, as already mentioned, the stock HEI system is fine, but the SA (spark advance) in the stock LG4 prom isn't. Upgrade to an L69 prom, set your base timing accordingly, and you won't believe the differences you just made. Good luck...

- Rob

RocketyMan

My L69 HO gets 20s MPG with a 5 speed and 3.23s in the rear. But that was before I really started messing with the carb. At 70 MPH I'm running at like 2100 ish RPMs. Which is pretty good.

I'm hoping to get a little more mpgs once I knock out a tiny kink with the carb.