zuhi

iTrader: (1)

Story for short.

We do rebuild 2 bird now.
One is a 85 build 86 model year 5.0L LG4 firebird.
And other is 82 build 83 model year 5.0L LU5

Both car lost the original 700R4 tranny in the past (don't know why).
Now the 85 car has TH400 the 82 has Th350 in.

First plan of us was drop out all of ECM and other wiring things from both car and put on each car an aluminum water pump little painting and decorative touch up here an there (open air cleaner chrome valve covers etc, and some new things like new timing, oil pump, etc What recommend in this time.

For the focus in the main question is. We plan to put on Edelbroc 2101 intake with 1406 e.choke carb. to put same performance in. And also a new vacuum controlled distrubutor instead of use the ecm controlled.

But as i hear and read it gives great power but gets extremely low mileage around 11/10 MPG! or less.

From the two cars the older, do not need power just need to runs fine because the CFI is a not a good thing all you know.

Some say better to stay with quadrajet. Because i will gets great (better then 1046) mileage if i add the LG4 car carb and ecm (carb was rebuild a year) and wiring to the 82 car. (the 2 cars has different owners) I dismounted both. And the wiring is still use able. And connections marked and some in my head. I can readd it to the 82 car, but i gets me lot of work and i do not want to see lot if wires in my engine bay.


So some question.

- Is it right i get extremely low mileage with Edelborck'c carb? (i do not interested for extra performance) I agree the standard horsepower.

- Do the new intake increase or degrease the MPG?

- The LG4 has the 2 sensor type Quadrajet. Do this has difference in MPG compared to the non sensor ones? (in rebuild cond it has almost 200$ difference) Dont know it is cam form only the sensors cost or one is better in MPG

- If i replace the stock electric distributor to a vacuum one can i still use the LG4 stuff correctly? (Sensor carb., map sensors, etc) or i do need to get a non sensor quadrajet.

- What is better i want to use the new vacuum distributor, get a 1406 Edlebrock or a non sensor rebuild quadrajet. (almost the same price at summit) (question is for MPG only)

Some says the idle control solenoid and stock choke can be an other vote on the quadrajet side. Now it looks like the Edlebrock can offer three things , performance, easy setup (fine tune), and if need rebuild, use less parts.

I found this carbs available fir bird (first 2) . Now i have the 2nd one with the blue and yellow sensor) third is for a 78 chevy, 4th at summit.


Will glad for any reply or tip/help! Thanks for all!

KrisW

iTrader: (5)

Well, everyone has an opinion but it seems not too many people are keen about giving theirs to you right now, hahhahh. No worries.

In my experience, there is NO carburetor better at giving good fuel mileage than the Quadrajet. When I am building a car that is a daily driver, regardless of the power level I want to achieve, if I am running a carburetor, then I am using a Quadrajet.

The Edelbrock carburetor is a fine carburetor, easy to tune and service, but does not ever give me the peak mileage that the old Quadrajet can. With the price you are paying for gasoline, do not consider anything but the Quadrajet.

So now for me, the question comes to picking WHICH Quadrajet. That depends on how well you like to tune cars that are computer controlled. The computer Quadrajet and fully electronic ignition will get slightly better mileage if you tune it properly. Since you are pretty far away from people familiar with tuning the old ECM in the car, I am going to recommend that you run the non-computer carburetor and distributor. I have family in Bulgaria and I know it is a pain to get American parts and tech stuff without paying too much for it. If you buy a good Quadrajet and a good distributor, you shouldn't have to mess with it for a long time afterwards.

I saw in your pictures that you are considering Summit Racing alongside the auto parts store carburetors. Again, I would take the simpler route and go with Summit. Get the distributor and carburetor together, swap them on, and be done with it. Then enjoy the cars.

Good luck!

Zane M

iTrader: (1)

My experience(not third gen), is we lost MPG when we changed from a Qjet to an Edelbrock in our '78 plow truck. Don't get me wrong, the Edelbrock runs fantastic, but it does not sip fuel nearly as well as the Qjet(even a worn out Qjet) did.
We changed carbs primarily for cost. Our Qjet was not a good candidate for rebuild, and a quality Qjet replacement was not cost effective for our rusty old plow truck.

Ozz1967

iTrader: (4)

I run the electronic Qjet in my 84 T/A L69, 5.0 and now 5.7 motor. Before the swap to the 5.7, I got 23mpg on a 26year old non-rebuilt Qjet and a 305 with 127000 miles on it.

When I swapped motors 2 years ago, I kept the Qjet. I now get 19-20 highway, 14-ish in town with the 355 (5.7L) motor.

Things to consider, since you don't have the 700R4, your mileage will suffer. The overdrive really helps on the highway. 3.73 gears with my 700R4 and I'm running 2600 RPM at 70mph (118 kph or so). With a Th350 your running at or over 3000 RPM. Now, depending on what rear gears you have this will vary, but it makes a huge difference when driving long distance. I would hazard a guess that you'll lose 3-5mpg if you don't have the 700R in the car.

I run an edelbrock performer, which is identical to the one you mentioned, except it's spread bore, designed for the Qjet. Square bore is for holley and edelbrock carbs. I like it, runs well.

Qjets, tuned properly, electronic or not, will get better mileage than a holley or edelbrock with comparable power. You cannot match their driveability at part throttle.

If you swap out to a non computer controlled carb, you must put in a non-computer controlled distributor to go with it. You cannot run one or the other, you must swap both. with the non CC qjet, you will lose a little bit of MPG. there is a reason they went to the Computer controlled version, simply put, it works better, when it's all hooked up and running right.

zuhi

iTrader: (1)

Thanks for all replies. And wait for more experience "more eye so more detail". But it looks lie better to use Quadrajet anyway.

I do need to compare the followings if i chose Qj.
Better to keep a 60k mileage distributor (with new cap rotor and wire set) with the one year rebuild CC QJ from the same car. And put them on to the 83 car.

OR buy a fresh vacuum distributor which came with new cap rotor coil and wire and a factory rebuild nonCC QJ from summit?

in my current knowledge the 2nd looks easier to maintenance. But i have all the wiring from the LG4 car and i do need to add fan and throttle kicker relay and choke relay to the other car to make it work. And i has fears the throttle kicker relay wont work if i leave the ECM system. (As i see fan relay and choke relays are standalone systems)

zuhi

iTrader: (1)

PS! i do not know what is the difference between this two QJ at summit.
As i see the finish color is different and the vacuum thing behind the choke. 2nd is available in a special kit for direct replacement and power increase on stock engines. Do not know it has technical or commercial issue why is not the first in this kit. Because if i chose -Chevy engine 305 -automatic and -86 i get result from the summit search engine to the first type. If someone know what is the vacuum thing are just please let me know. The available data for compare do not clear this info and price is same!
SUM-210216
http://www.summitracing.com/parts/su...make/chevrolet
SUM-210200
http://www.summitracing.com/parts/su.../rotatingmodel

Apeiron

The "vacuum thing" is the vacuum break for the secondary air valve.

They're the same carb, just tuned differently out of the box.

zuhi

iTrader: (1)

As i understand this valve is used for vacuum adv. distributors? or an other from the carb base?

oh both 3 speed tranny need a vacuum. Can i use any from the carb base or do i need to use a specific one?

Apeiron

It has nothing at all to do with vacuum advance on the distributor.

For the transmission modulator valve you can use vacuum from a port on the manfold or the back of the carb base.

KrisW

iTrader: (5)

I'd run the 210216 carburetor from Summit. Its for a lower horsepower application, which will most likely mean better gas mileage for your 305 engine.

Don't forget the vacuum distributor too.

http://www.summitracing.com/parts/su...make/chevrolet

zuhi

iTrader: (1)

Hi all!

I do not really understand what is that vacuum ting on the mentioned carbs side and how i can or i need to use it if it necessary for my setups. Or any noticeable difference between them?
And for the vacuum distributor i just need to leave the adv. as is (not connected), blocked with cap or free to air?

I planning this combination:

(just listing the main parts)
For both car EDL-2101
http://www.summitracing.com/parts/edl-2101
EDL-1406 (for thr 85 car)
http://www.summitracing.com/parts/edl-1406
And for the 83
SUM-210216
http://www.summitracing.com/parts/su...make/chevrolet
OR (do not chose jet, may i stay with the CC QJ)
SUM-210200
http://www.summitracing.com/parts/su.../rotatingmodel
For both car PRO-141-683
http://www.summitracing.com/parts/pro-141-683
For both car PRO-67265
http://www.summitracing.com/parts/pro-67265
For both car MRG-4364
http://www.summitracing.com/parts/mrg-4364
For both car MEL-3-163S
http://www.summitracing.com/parts/mel-3-163sb

Please check this parts or OK or better to chose different types or brands. Or they are OK?

Regards:László

zuhi

iTrader: (1)

Getting closer to final decision.

I do not put my vote CC or not CC QJ.
Still in the versus (both fresh rebuild) (see picture)
Summit's SUM-210200 and ROCKAUTO'S AUTOLINE Part # C9652

The question is MPG! what is the difference between them?
Anyone with experience in this subject to assume pros and cons?