67 camaro serious gas guggler maybe 8mpg please help - Team Camaro Tech
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post #1 of 10 (permalink) Old Aug 31st, 08, 06:26 PM Thread Starter
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Cool 67 camaro serious gas guggler maybe 8mpg please help

hello my 67 camaro has a 327 with a 4 bbl carb and a 350 turbo trans, it also has an electric fuel pump, the issue is i like the power and everything but its a serious gas guggler, i literally think im getting 8 miles per gallon going down hill, outside the tank adjacent to the wheel well there is an electric fuel pump, that always hums when i turn the key, is there a chance that the thing is pumping way to much gas, i know this may sound like a stupid question but are there electric fuel pumps that are more fuel thrifty? or should i go back to a manual pump all toghther, i dont know the pros and cons rather i do know electric fuel pumps started out to prevent stalling and flooding etc, i just dont know how cost effective they are..

with all this being said my gaol really would be around the 13-15 mpg which i think is fessiable i even thought about replacing the manifold back to 1 that fits a 2bbl but than again i think it would drive me insane if i couldnt pass some of the people that come up and "rev" their engine especially when they are in some foreign honda or something..

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post #2 of 10 (permalink) Old Aug 31st, 08, 09:19 PM
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george
 
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Re: 67 camaro serious gas guggler maybe 8mpg please help

Quote:
Originally Posted by knightmoose View Post
hello my 67 camaro has a 327 with a 4 bbl carb and a 350 turbo trans, it also has an electric fuel pump, the issue is i like the power and everything but its a serious gas guggler, i literally think im getting 8 miles per gallon going down hill, outside the tank adjacent to the wheel well there is an electric fuel pump, that always hums when i turn the key, is there a chance that the thing is pumping way to much gas, i know this may sound like a stupid question but are there electric fuel pumps that are more fuel thrifty? or should i go back to a manual pump all toghther, i dont know the pros and cons rather i do know electric fuel pumps started out to prevent stalling and flooding etc, i just dont know how cost effective they are..

with all this being said my gaol really would be around the 13-15 mpg which i think is fessiable i even thought about replacing the manifold back to 1 that fits a 2bbl but than again i think it would drive me insane if i couldnt pass some of the people that come up and "rev" their engine especially when they are in some foreign honda or something..
You have a little thingy called a needle and seat inside your carb.As long as the supplied fuel pressure does not overcome the needle and seat..the fuel pump swap will not affect mpg.I would steer clear of a 2 barrel.You would gain more hp and mileage with a spread bore quadrajet.The primarys are small and the secondarys are huge.Drive her easy..never roll open the secondarys until you want to take it to the ricer crowd.

George
68 Camaro
8-71 blown 461 Rat on E-85
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post #3 of 10 (permalink) Old Aug 31st, 08, 10:53 PM
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Todd
 
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Re: 67 camaro serious gas guggler maybe 8mpg please help

A couple more gears would sure help
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post #4 of 10 (permalink) Old Sep 1st, 08, 04:52 AM
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Re: 67 camaro serious gas guggler maybe 8mpg please help

"...especially when they are in some foreign honda or something.."LOL - Amen to that. I will be changing out to 4bbl probably this winter. I have all the parts just haven't had the time.
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post #5 of 10 (permalink) Old Sep 1st, 08, 06:49 AM
 
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Re: 67 camaro serious gas guggler maybe 8mpg please help

My stock 350SS w/ an M-20, 3.31 posi- and 25.5" tall tires would get like 17 mpg on the hwy when new back then if I stayed out of it.

Get in her and I never checked!

I had my Q-Jets top rear butterfly's set to where I could sneak up on 65 mph, maybe 70, before they started to suck open.

pdq67



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post #6 of 10 (permalink) Old Sep 1st, 08, 07:14 AM
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Charlie
 
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Re: 67 camaro serious gas guggler maybe 8mpg please help

First thing you should do is find out how much fuel pressure that pump is pushing. Chances are though, if you don't smell gas, it's not over powering the needle/seat. Like it has been suggested, the spread bore style carb is the way to go for a street car and especially one that wants more MPG. The small primaries are great, especially if you don't get into the secodaries(rather large). I run a 350 with a Powerglide and 4.10's and I get around 10-12mpg, depending on how I run her and that's with a square bore style carb. I am switching over to a Q-Jet though to get the best of both worlds. The Q-Jet can be a formidable street fighter carb. It can even be a nice drag strip carb. Just ask the Nostalgia class guys.

Charlie Knudsen 67 Camaro RS/SS 350 TKO 600, 4.10's, AFR 195 Street Heads, Comp 270H, Rhoads Lifters, Crane Ignition, Pertronix Dizzy, Performer RPM Q-Jet, Heavily Modified Q-Jet, Hooker Comp Headers, MagnaFlow 2 1/2", 144 Decibles(Alpine CDA-7998 Head Unit, RF X7 and RF 750X Amps, MB Quart Mid's & High's, Kicker L7 12" Solo Barics)
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post #7 of 10 (permalink) Old Sep 1st, 08, 10:47 AM
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Hank
 
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Re: 67 camaro serious gas guggler maybe 8mpg please help

What 4 bbl carb are you using?
What size are the jets?

MBHD

Chevy 250 turbo EFI
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post #8 of 10 (permalink) Old Sep 1st, 08, 05:22 PM
Tom
 
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Re: 67 camaro serious gas guggler maybe 8mpg please help

1- connect vaccum gauge and adjust carb to pull most vaccum, stock cam should have 18-24hg, also, check for vaccum leaks, check trans vac line coming off intake and runs to back of trans, is steel line but has rubber connectors.
2.make sure distributors vac advance is working, may be hooked up to wrong port on carb.
3.check your plugs and wires - are all plugs firing? test compression to make sure your engine is healthy and tunable
4 is your speed-o -meter correct. if not your odometer may be registering more miles than you are really going. thus throwing off your mpg's
could be many many things -
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post #9 of 10 (permalink) Old Sep 2nd, 08, 07:08 AM
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Charlie
 
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Re: 67 camaro serious gas guggler maybe 8mpg please help

I agree with the vacuum advance. Make sure it is working the way it should. At cruise, the vacuum advance will definately help with gas mileage.

Charlie Knudsen 67 Camaro RS/SS 350 TKO 600, 4.10's, AFR 195 Street Heads, Comp 270H, Rhoads Lifters, Crane Ignition, Pertronix Dizzy, Performer RPM Q-Jet, Heavily Modified Q-Jet, Hooker Comp Headers, MagnaFlow 2 1/2", 144 Decibles(Alpine CDA-7998 Head Unit, RF X7 and RF 750X Amps, MB Quart Mid's & High's, Kicker L7 12" Solo Barics)
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post #10 of 10 (permalink) Old Sep 2nd, 08, 01:40 PM
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Steve
 
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Re: 67 camaro serious gas guggler maybe 8mpg please help

what is your rear end ratio?
What RPM does your engine turn at 60mph?

Steve
1968 that started life and a 6 banger with a PG. Now it's a 350 with a TKO600, Moser 12 bolt, Speedtech LCA/UCA, ATS Tall Spindles, Hotchkis Springs, Forgeline ZX3P, C5 (Kore3) brakes with other cool stuff from Ron Davis, Vintage Air and soon to be Terminator EFI.


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