Carb comparison

[slant6billy]

I currently run an Edelbrock 750 with an e choke and mopar cable bracket. I had run a beat holley on the car. I went with the Edelbrock as folks said they would pass the tailpipe emissions test. I've also heard many folks say that the holley will get you down the track a bit quicker. So my goal at first was to get through the tailpipe test and I did on the Edelbrock. Now the state no longer cares about vehicles made before 1996. So I grabbed a tuned holley that was running on a mopar small block ( Barracuda Formula S 340) yesterday. The Barracuda has less cam and less bore than my car so I can't compare car to car for this test. The fish has 3:23 gears too, so that too can't compare to the 4:30 in my Volare'. So I'll be running a test like this; my current tune on the Edelbrock and then the change to the Holley. Since it is ungodly hot I have to do this in the early am- one day apart to allow for the swap of carbs.

 

[BudW]

I'm glad they changed the emissions rules there.

Keep us up to date on your results.

 

[Aspen500]

JMO but, not impressed with the Edelbrock carbs. Had one on my car in it's former life and never could get it calibrated to run good on idle, cruise and acceleration all at the same time. Like you, bolted on a grungy old Holley a buddy had laying on the shelf and it ran great as is. Calibrating probably would have made it even better. A coworker recently bought a '67 LeMans with an Edelbrock carb and he went through the same thing. No amount of calibrating with jets, rods, springs, idle air bleed modification, etc could make all 3 modes work all at the same time. He's got a wide band A/F gauge and knows what he's doing. Finally built himself a Quadrajet and the car runs like a dream now and seat of the pants has better power and mpg went from 11 avg to almost 14 mpg. Just saying.............................

 

[slant6billy]

Part 1 Baseline run with the Edelbrock:

 

[BudW]

Need a more rural area for testing.

 

[slant6billy]

Need a more rural area for testing.

Yeah, I know. It was 8 am on a Saturday about 80 degrees. Most people were still fighting a hangover. Tomorrow I run the holley. It is already installed. Could be quick or could be permanent

 

[Cordoba1]

Like others have said, I fought and fought with Eldelbrock carbs, and could never get them to run well under all conditions. A friend suggested (and donated) a Carter AFB. Wow! Can't believe how easy it was to calibrate. And why don't all carbs have those huge nobs right up front for setting the idle mixture? Didn't even need a screwdriver for most of the adjustments. I'm one guy with one opinion, but I love AFBs.

 

[slant6billy]

Got it going this morning. A slight better bottom end. Chirped 1st and 2nd out of the hole. My wife is concerned with my abuse of tires and tupperware. Part 2 video is processing now

 

[slant6billy]

Part 2 ... Now with the Holley Street Avenger. To Note: Both carbs were run at about 8 am and 80 degrees with the similar humidity. With the Holley there are some neat differences.

 

[Justwondering]

okay, I know nothing about what you are doing but the 2nd road trip definitely sounds better than the first.
Here's my novice questions.
What is chirping?
Is that a good thing?
Is it a sound or a gear change?

 

[slant6billy]

okay, I know nothing about what you are doing but the 2nd road trip definitely sounds better than the first.
Here's my novice questions.
What is chirping?
Is that a good thing?
Is it a sound or a gear change?

Very good questions. You are practically in the right realm of things by how you are asking them. So, a typical old car like these FMJs has the 3speed auto most likely. Some rare M bodies have stick shift and a good number of Volare' and Aspens have stick shift as well. But for the most part the automatic trans was the most common. My car has the smaller mopar 904, which could be a 998 or 999, but we'll just go with 904. Now lucky folks with a good order option or package got the 727. Walley's 79 has a 727. Those are a bigger beefier trans. Longer tallshaft and thus shorter drive shaft- which makes them much stronger. Now it is easy to "break the rear tires loose" or "Chirp" the tires with a stick. Just rev the engine and dump the clutch in first gear. Even the Slant 6 can bust the tires with a stick. Now, with an automatic, there is a little bit of delay or disconnect. The engine is spinning the torqueconvertor. It is basically a big pump. It pumps pressure to the input shaft and the gear sets are shifted Automatically. There are other threads about shift improvement kits, so I'll steer away from that topic. So when the car launches from a dead stop there is some chirp from the rear wheels. Both rear wheels if the mopar has a "Sure Grip" differential or one wheel if it is an open rear differential. Now, one wheel "open" type is taking all the power, so that wheel gets spun or gets to spinning a bit more from a dead stop. A "Sure Grip" splits the power to both rear wheels and allows for a better launch. Now. I've slipped up and called it a "posi".... that is a chevy term and is death by hot laval on the mouth. So we don't say that 'round here no more. Back to the chirp; too much tire (in my case) is really difficult to leave a classic Dukes of Hazard Wheel smoke out. Or on the other hand, too much power and not enough tire will cause a "Sit and spin" moment. Lots of folks get beat by chevy cobalts, because the uncontrollable spin of the rear tires. I'm running a tire called a "Drag Radial" Now, that does not mean a tire in a dress or so transgendered rubber donut. It is a radial constructed tire with a super grip - almost like a dragster slick, but with D.O.T. approval for road use (just barely). I don't drive the car in the rain and park it if I get caught in even the slightest bit of precip. So the drag radials don't put on a neat smokie burn out show. They grab like glue and the car goes like it got smacked in the rear. Getting a small amount of "chirp" is just a side effect of Zero inertia on a 3600 pound car and the torque of the tires breaking loose. The drag radials are quick to grab the road and push the car forward. However, in the case of today, as I manually slapped the shifter from 1st to 2nd gear at about 5500 rpm, there was enough incoming torque on the rear wheels to chirp the tires again. The bad, that is a lot of strain on the drivetrain. Everything from the 904 trans, driveshaft, and 8 1/4 rear. The tires don't give much in terms of slippage and that means somewhere else is going to find breakage. Hopefully, that explains it. Or over explains it.

 

[Justwondering]

Chirping is basically, its the tires making noise when you accelerate quickly.

You are walking a fine line between giving power (carb tuning), rotating tires (grip selection), and a really short amount of time to get the rpms up really high.

You are working on the best combination to accomplish all that by tuning or de-tuning the type of tires, carb, engine, gear ratio, and driver skill.

I need to keep reading threads but this is beginning to make sense.
Thanks for taking time to answer my questions.

 

[slant6billy]

That's about it. There will be a real test at Englishtown New Jersey on Aug 20th for the all out mopar day. Luckily Gator has my back and a trailer to pick the pieces up after the BIG BOOM!

 

[BudW]

You know you are making a decent amount of power when you can chirp the tires on the 1-2 gear upshift - which “chirp” refers tp the noise the tire(s) makes (losing traction for a brief moment).

Usually, on wet roads, that chirping “effect” can get a car sideways upon those shifts, because tires can’t keep traction as well when wet.

Slant6billy, can you show me a picture of your camera mount, please?
I might want to make or use something like that, myself.

 

[slant6billy]

You know you are making a decent amount of power when you can chirp the tires on the 1-2 gear upshift - which “chirp” refers tp the noise the tire(s) makes (losing traction for a brief moment).

Usually, on wet roads, that chirping “effect” can get a car sideways upon those shifts, because tires can’t keep traction as well when wet.

Slant6billy, can you show me a picture of your camera mount, please?
I might want to make or use something like that, myself.

The camera mount is actually a yardsale camera tripod. One leg is footed to the passenger front seat inward seatbelt mount and the other leg footed at the driver inward seatbelt mount. The third is utilizing the center of the back seat at the point wher the seat back meets the bottom. It is secured with the center rear seatbelt (My coupe has a middle seat belt- not sure if that was dealer installed) Tyraps hold the tripods forward legs to the front seat feet. I wanted something to see the dash gauges and mostly the tach. That is, if there is ever a need to see at what rpm something occurred. I want to mount a camera from the dome light

 

[Justwondering]

Dome light cameras. Now that would be cool

 

[Aspen500]

You know you are making a decent amount of power when you can chirp the tires on the 1-2 gear upshift - which “chirp” refers tp the noise the tire(s) makes (losing traction for a brief moment).

Usually, on wet roads, that chirping “effect” can get a car sideways upon those shifts, because tires can’t keep traction as well when wet.

Slant6billy, can you show me a picture of your camera mount, please?
I might want to make or use something like that, myself.

..............and you know you went overboard when the tires go up in smoke on the 1-2 shift during "spirited acceleration"

I've been trying to come up with a camera mount that is steady, easily removable, requires no vehicle mods and most important does no damage to anything.

 

[BudW]

I've been trying to come up with a camera mount that is steady, easily removable, requires no vehicle mods and most important does no damage to anything.

Which is why I asked.

Next Idea I have is to, somehow, have data in the video (much like a picture time/date stamp) that is showing RPM, speed, decibels, etc. (whatever you want) along the bottom or corners of video.

I think one could unbolt the dome lamp and let it hang, while using the mounting holes to attach some kind of bracket for such (maybe even temporary screw dome lamp to bracket sideways).
Might even use the dome lamp as a power source - but that would require cutting and splicing.

Before I perform major vehicle modifications, I would like to record before/after videos - much like what Slant6billy has done, for my own benefit. As a plus, I could post here, as well.

One thing I need to get, and soon, is obtain some kind of a portable ET monitor or something I can use other than the seat of my pants. I know they are out there, but have no experience with them (yet).

BudW

 

[BudW]

The camera mount is actually a yardsale camera tripod. One leg is footed to the passenger front seat inward seatbelt mount and the other leg footed at the driver inward seatbelt mount. The third is utilizing the center of the back seat at the point wher the seat back meets the bottom.

It works, but rattling a bit annoying. Not sure what can be done, though.

My coupe has a middle seat belt- not sure if that was dealer installed

I could be wrong, but I believe all FMJ’s were equipped with seat belts for six people - unless you have a center console. The videos don’t show a console.
It could be a car someone converted to a console, maybe, and if so, they left the extra seat belt in place. I don't know.

 

[6thGenImperial]

Like others have said, I fought and fought with Eldelbrock carbs, and could never get them to run well under all conditions. A friend suggested (and donated) a Carter AFB. Wow! Can't believe how easy it was to calibrate. And why don't all carbs have those huge nobs right up front for setting the idle mixture? Didn't even need a screwdriver for most of the adjustments. I'm one guy with one opinion, but I love AFBs.

You do know the Edelbrock Performer Series carbs are an updated Carter AFB design, and the Thunder Series are updated Carter AVS designs?