So there will be less fun shortly...
Thread Starter
Melting Slicks
Joined: May 2007
Posts: 2,382
Likes: 2
From: Kathleen FL
weren't you the one going on about how great of gas mileage you could get with a carb and that efi is just a bunch of trouble and a waste of money to pursue cause of the high cost of parts?? funny how fast that went out the window.. i bet you the harness isn't as hard to replace as you think.. if you can change a heater core in 2 hours i think you may be able to change out the harness.
Le Mans Master
Joined: Oct 2003
Posts: 6,130
Likes: 2
From: seattle WA
Those mechanical secondaries are a major factor in your poor mileage, coupled with driving style of course. Rodders used to like those spread bores as you called them, also called quadra pukes. But really, for those that really know the Quadrajet they are a good example of what fuel economy and performance can be had out of a carb.
Last edited by rick lambert; Apr 6, 2008 at 10:46 AM.
Race Director
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
Originally Posted by pr0zac
weren't you the one going on about how great of gas mileage you could get with a carb and that efi is just a bunch of trouble and a waste of money to pursue cause of the high cost of parts?? funny how fast that went out the window.. i bet you the harness isn't as hard to replace as you think.. if you can change a heater core in 2 hours i think you may be able to change out the harness.
Yep! That wiring harness has a plug at every connection. How tough can THAT be? It should be duck soup compared to a C4 heater core. You could probably do it on your lunch 1/2 hour.
Your best mileage of 14, that you seem to be OK with, would be about your worst with EFI.
RACE ON!!!
Melting Slicks
Joined: May 2007
Posts: 2,171
Likes: 1
From: Warwick RI
I went with the vacuum secondary myself as it was the one recommended for street use in vehicles over 3000 lbs if I remember correctly from the Holley website. I even went on the small side of the CFM recommendation for my motor and it seems fine.
Thread Starter
Melting Slicks
Joined: May 2007
Posts: 2,382
Likes: 2
From: Kathleen FL
Yep! That wiring harness has a plug at every connection. How tough can THAT be? It should be duck soup compared to a C4 heater core. You could probably do it on your lunch 1/2 hour.
Your best mileage of 14, that you seem to be OK with, would be about your worst with EFI.
RACE ON!!!
Team Owner
Joined: Oct 2004
Posts: 81,241
Likes: 3,063
From: altered state
St. Jude Donor '05
Hate to rock the boat but how the hell are you gonna get 20mpg with a carbd/cammed stroker, no way. Even a 350 I would question that .
You can feel the secondaires in your gas pedal, tune the hell out of the car and stay in the primaries.
You can feel the secondaires in your gas pedal, tune the hell out of the car and stay in the primaries.
Melting Slicks
Joined: Aug 2003
Posts: 3,399
Likes: 394
From: Lakeville MI
Have you done any tuning of the accelerator pumps, power valves or even jetting?
You could try some later opening power valves (lower vacuum), less agressive pump cams, smaller shooter nozzels, etc.
If you can eliminate the overfueling, if that is the case, you should see some improvement. If the fueling is already spot-on, then there's not much you can do.
I wouldn't be surprised if you're running on the power valves much of the time.
You could try some later opening power valves (lower vacuum), less agressive pump cams, smaller shooter nozzels, etc.
If you can eliminate the overfueling, if that is the case, you should see some improvement. If the fueling is already spot-on, then there's not much you can do.
I wouldn't be surprised if you're running on the power valves much of the time.
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Thread Starter
Melting Slicks
Joined: May 2007
Posts: 2,382
Likes: 2
From: Kathleen FL
I would think it would be possible with tuning. I thought I had tuned the carb correctly, but I'm thinking crappy fuel economy from "spirited driving" is due to the DP, less the cam. I know I could probably figure out a way on how to make those secondaries open a little later. On a better note yesterday, the car dynoed at 445 rwhp @ 5800 and 477 tq @ 3600. Now that is C6 Z06 territory!
Thread Starter
Melting Slicks
Joined: May 2007
Posts: 2,382
Likes: 2
From: Kathleen FL
Have you done any tuning of the accelerator pumps, power valves or even jetting?
You could try some later opening power valves (lower vacuum), less agressive pump cams, smaller shooter nozzels, etc.
If you can eliminate the overfueling, if that is the case, you should see some improvement. If the fueling is already spot-on, then there's not much you can do.
I wouldn't be surprised if you're running on the power valves much of the time.
You could try some later opening power valves (lower vacuum), less agressive pump cams, smaller shooter nozzels, etc.
If you can eliminate the overfueling, if that is the case, you should see some improvement. If the fueling is already spot-on, then there's not much you can do.
I wouldn't be surprised if you're running on the power valves much of the time.
