Well I should probably introduce myself as I am new to the board. The name is Jon and have been into mopars most of my life, unfortunately I recently had to sell my prized '72 four speed roadrunner in order to put myself back into school. I ended up missing the thrill of a fast car, though with college sucking my money faster than a drunken spree in vegas I had to find a budget muscle car. I ended up picking up a lein sell 85 camaro z28 for the grand sum of $1100. The previous owner, whoever that might be, did some modifications to it. Regardless because I am stuck in california our emissions are quite strict. I am looking to upgrade my carb as I have the electronic feedback quadrajet still on the car, yet still keep it semi emissions legal. I have read the archives already and see the tuning tips, but is there any superior aftermarket bolt on carb that can still pass emissions?

Thanks
- Small Tires

 

the eldbroke carb should do the trick.

 

There are no aftermarket carbs which are emissions legal in California. Replacing the Qjet isn't always an "upgrade" anyway.

 

There is NO OTHER carb that's California legal. Your only choice, besides swapping to a newer motor, is to repair what you've got. Carb, distributor, ECM, wiring, all emissions devices, must remain intact as installed by the factory.

And that carb is FAR FAR FAR from being the limit to that engine's performance anyway, meaning there's nothing to be gained by swapping it, that can't be gained by tuning it instead. It's rare indeed that one makes a car faster, or otherwise any better except in the eyes of people easily distracted by shiny things, by simply un-bolting and re-bolting big things that sit up on top of the motor where everybody can see them.

If you actually want to make the car faster, the place to start is the exhaust; all the way from the heads to the street. If your car has the LG4 engine (8th digit of the VIN is H) then EVERY SINGLE PIECE needs to go away, and be replaced by the stuff for the L69 (VIN code G). All of which, if chosen correctly, will retain emissions legality while uncorking around 30 HP at a single stroke. I'd suggest Edelbrock TES, I think the part # you will want is 6874; I'd strongly recommend getting them with the ceramic coating. You can get a high flow cat for a little over $100 from Summit; Catco part # 4116. THen all you need is the cat-back exhaust of your choice, such as Edelbrock, Hooker, Dynomax, Slowmaster, etc. etc. etc. Just make sure you get the stuff for L69 (Vin code G) and all will be well. It all has to go as a complete assembly. DO NOT get ANYTHING that will fit LG4, as ANY LG4 stuff will preserve the bottleneck, and waste all your money.

 

Don't be so hard on the LG4. With exception to the camshaft, the LG4 and L69 shared long blocks starting in 1985. The LG4 had the same 9.5 compression and Electronic Spark Controller.

The L69 had a better camshaft, different jetted carburetor and distributor advance/spark control to take advantage of the camshaft, free'er flowing exhaust manifolds, larger diameter exhaust system with high flow catalytic converter, and of course the electric cooling fan. The biggest thing that boosted the L69 was the camshaft.

 

I'm guessing you've never had a L69; only LG4s.

The single biggest difference between the L69 and the LG4 was THE EXHAUST. Which is why it's THE SINGLE BIGGEST UPGRADE you can make to the LG4. Look at the 2 of them side by sode, you won't believe how dinky the LG4 stuff looks by comparison. It looks like setting a drinking straw next to a water main.

The cam was different too, you're right. I'd rate that as one of about 2 or 3 candidates for the title of "second biggest upgrade". The others are the compression (depending on the year of LG4 of course), and the air cleaner. Compression is obviously a bit of a challenge to change with bolt-ons.

Then of course there's the CAR, apart from the motor; LG4 cars typically got grandma-grocery-cart gears, which if you put actual performance gears in one, after getting it to breathe, such as 3.73s, make a MASSIVE difference. 3.73 of course being the stock gear for L69 cars (most of them anyway).

 

He was talking about exhaust stuff.

The electronic q-jet is badly misunderstood. It's a great street performance carb. Do 290 rear wheel horsepower and 24 highway MPG do anything for you?

 

A GM makes horsepower the same way a Mopar does.
If you want it to make more power, make the motor pump more air. The CC Qjet when fully open flows 795cfm.
The horsepower part of it at WOT is not affected by the computer control. it is calibrateed by jets and metering rods just like a carter thermo quad. 70% of the airflow at WOT flows thru the secondaries on a Qjet. This is where you shou look for more performance. You can buy performance parts for your CC qjet from Edelbrock.

The secret to getting better performance and getting past the smog ****'s in California is to keep the motor appearing dead stock. Keep the CC qjet and modify the secondary side for correct AFR at WOT. Enhance every thing else in the airflow chain without makeing it look non- stock. Pull the heads and fully port them with larger valves. (big improvement here) Mill them to increase the cr. Replace the complete exhaust system with a complete smog legal exhaust system that flows more air and passes a smog inspection. Consider a custom system with two high flow cats.
Replace the camshaft with a better one that makes more power but still passes an emissions test. there are tons to choose from.

Ditching the stock cc Qjet carb is just going to cause you problems and will not in itself improve the performance of your car.
It flows plenty and can be recalibrated once you've modifed the rest of the motor for better airflow.

 

I agree, keep the Electronic Quadrajet. My grandpa's 88 Cadillac has a nice 455 Olds in it, to replace the tired SUPER high mileage 307. The electronic carb/distributer is still in place. The major changes to the carb was primary jet, secondary hanger, secondary metering rod, set the mixture control solenoid, idle mixture screws, and some tweaks to the Base Timing. Car runs great, passes smog, and gets good relative mileage. 17 MPG sound good from a 455? OD and a 2.53 gear will do that. With the small cammed 455 in it making maybe 300 RWHP it is just as smooth and quiet as the 307. Perfect sleeper.

 

Thanks guys for all the advice. I figured I would improve on what was there, though I have not dealt with alot of electronic stuff in cars. The car already has a flowmaster catback with edelbrock shorty headers but the cat and down pipes are stock, so I was planning on replacing this section of the exhaust. I figured for the rest of the motor it would be a few upgrades. I already have a full MSD ignition for it (distributor, 6al, wires, coil) and other minor things. I was hoping that maybe I could ditch the factory carb but it sounds like with a little bit of elbow grease that I can get the thing running pretty well despite the computer controlled BS. Is there any other area I should concentrate on for more performance gains? I already have a decent cam, semi worked heads (large stainless valves, runner work), and a semi decent intake coupled with a ram air hood and gears out back.

 

or keep it, throw it on for when ever u smog, buy another one the day after, i dont see the dilema

 

when they do an emissions test do they test at wot? if they blow your motor who pays?

 

No, they don't go WOT. That's the whole point. The computer will maintain control of the primaries, which is all that will be used in the emissions test. The two versions typically used are: 1) idle and "cruise" RPMs (like 2500 RPMs); or 2) a dyno test that sniffs while "simulated" stop & go and highway conditions are run.

The secondaries therefore can be tuned for the WOT performance.