hey sweeet76 & weyum850, not to get off subject, but when is the big Vette cruise-in in Pensacola? I have an old military buddy there, near the beach, and said I was gonna make that one, and hang out. Thanks!

 

If the induction system cannot provide enough air to properly mix with the fuel, the power produced will drop off.

Gordon's comments are right on.

I opted for a torquey, responsive 383 with gearing that does not require more than 5500 RPM. With my enlarged runners and throttle body, I have no problem with airflow.

 

Is it Leo?

 

Sounds good!

 

Never heard of it. I would like to know when if their is one tho haha.

 

if somebody wants to experiment with efi, i'd say TPI is your best bet. inexpensive service manual, lots of c4 guys use it, there are lots of aftermarket mods like Extrude Hone for more airflow.
low cost used and it is true port injection, with numerous injector sizes avaiable.
the price is right! and it can be re-sold fast if for any reason u don't like it.

 

I read your article and dont understand most haha. I'm only 20 and dont know that much about carbs ... In English :-) ... what do i need to get 16+ mpg? 4165-6210 and what else? What intake do you recomend?

Thanks Will

 

I have a Holley 670cfm throttle body adapted to a GM system. Runs great. But if I knew what I know today, when I bought it, I would have set up a TPI system. It is by far the least expensive way to go for the most performance. There are many other systems out there that all work well. But you will spend a significant amount of money on them. Bottom line is how much do you want to spend? Performance and reliability wise FI is the way to go.

 

i don't know the details of your engine/car. i had a 76 c3 that got 13. changed entire exhaust to 72 pipes & turbo mufflers, went up to a best of 17.6, 16 typical.
see my new article on mpg secrets http://community-2.webtv.net/MATTGRU/EFIMPG

 

Another reason to use EFI....Flex Fuel.

Where I live is E10, but if I go 30 miles up the road, it is straight 100% gas. Different jets needed to optimize power and mileage. Also, I can't use E85 if I want to.

There is a company that offers the components to convert a Gen I SBC to coil pack ignition controlled by a LS1 computer. You can go carbed or EFI. If you go EFI with this setup, it is a short jump to a DBW throttle body which means cruise is easy.

I am more interested in making a Flex Fuel SBC. Combine EFI with a GM fuel composition sensor, wideband O2 sensors and a computer programmed to compensate the AFR based on ethanol content (2003 trucks) and you have a SBC that can run on almost anything that you can fill up with (except diesel).

My car is a hobby and I consider this an interesting challenge.

 

I don't know how technical you are but have you considered Megasquirt?

There's a good article on Car Craft.

http://www.carcraft.com/techarticles...ion/index.html

This is there test set-up and dyno sheet.

 

"I am more interested in making a Flex Fuel SBC. Combine EFI with a GM fuel composition sensor, wideband O2 sensors and a computer programmed to compensate the AFR based on ethanol content (2003 trucks) and you have a SBC that can run on almost anything that you can fill up with (except diesel)".


I like how you think- we have a bunch of E85 hear and you can make great power on that stuff!!!
Any aftermarket for Flex Fuel yet?

 

With my Blow threw Carb I just had twice the problems of a normal Carb and was in the 9mpg range myself. My 8 year old Truck Starts just like a new Car should. I now have the Accel EFI and now my Vette starts just like a new car should. As far as I know a Duel Plane Manifold is not even offered with EFI. One should be able to tune a Carb but lets face it your trying to out smart a computor. However you can buy a lot of Gas for the cost of a EFI. If we were trying to be as cost efective as we could we wouldn't own these Cars.

 

I have a 427 sbc with a FAST XFI setup on a custom ported Motown single plane intake. solid roller cam. My signature shows the setup. It has an MSD crank sensor because I had problems with the dual sync FAST distributor. This was not the easiest system to figure out how to tune for a novice, but now that I'[m familiar with it I like it.

 

You can buy pre-built Megaquirts now, TPI looks like a good choice as a setup to be megasquirted.
Perhaps microsquirt + MSD 6A ?

 

Weyum850 I am in the same boat you are. I just turned 18 and drive my 76 everyday to school getting 9.8 mpg. Heck our family 91 chevy truck even gets better gass milage. Let me know what you end up doing.

 

To Weyum850, I don't understand what makes You think that Fuel injection will double Your MPG's?? this is not logical at all, for a carb to use twice as much fuel as FI the mix would have to be twice as rich, something’s got to happen with all that fuel right??
Plus You're spreading some misconceptions about FI being something newer than a carb - You are dead wrong - they both the same age (remember hot bulb engine from XIX century?? two stroke heavy oil engine with fuel injection).
plus Your trying to upgrade to TPI- with all respect to TPI guys "mono" injection was abandoned two decades ago, If You want to upgrade to EFI You need to go to individual injection - YET STILL IT WILL NOT DOUBLE YOUR MPG!!

I think that if You decided for a 383 to be Your daily driver You need to deal with the MPG's :P if anything I would definitely look into Your transmission?? (please don't say You got a 400 in Your daily driver and want to double Your MPG's with EFI) also what’s the ratio in the pumpkin?? what size tires?? do You drive with T-tops off?? ...and remember, the biggest improvement in MPG's comes from driving style changes...



Hope I didn't offend anyone!

 

Believe it or not, I have read all 3 pages of this thread, ..now a couple words of my experiences over the last ~20 years ....

I used to have a Pontiac 455 in a '70 Lemans Convertible, thm400, 12 bolt 321 posi rear 15" tires it had the obvious Qj on it for some 3 years, it was my tow car, as well as schlep mobile for the little kids, long about '92 I had my second vette, a stone stock '87, and so it was maybe the 5th car with some sort of FI on it, over the years...I loved the operational characteristics of it,....a friend stored his '79, 455 Hurst Olds race car in my garage for a time, he had a TBI setup on it, I got the idea of putting FI on my Pontiac.....Junkyard run yielded a DPFI setup off a '79 Sedan DeVille 425, I cobbled it onto the Pontiac with help from a good TIG welder on the aluminum Edel dual plane mani.....running the stock Bendix computer/wiring from the Caddy...got me ~40% better fuel economy over the Qj, and it was not even closed loop operation, and driveability was MUCH IMPROVED, instant throttle response, dip toes into the pedal and that car instantly pulled like a Peterbuilt, the noise from 1000 cfm t-Body was loud enough and the dual exhaust ripped from idle to whatever....winter or summer....

so with that success, I turned to the boat, just a '85 20' Bayliner with a Volvo i/o and 2100 engine, had a single barrel solex on it...that thing would tow the kids around on the river for about 2-2.5 hours before running outta gas....so I found that huge improvement with FI on the Poncho, I got a Turbo Volvo DPFI intake setup from junkyard, along with a GM 2300 Grand Am computer, I was looking more for ease of operation/starting, as that Solex had no choke, making that boat a bear in cooler weather mornings....hated the POS....
I consulted with a USCG local DC area engineer, who was chief liaison working on FI with the BIA..boating ind. assn.....so fire/safety was an issue, especially with kids on board...after the project was finalized, the thing ran over 4 hours on the river, and picked up THREE prop sized, the torque on take off was nearly doubled, I went from a ~14" 3 bladed aluminum prop to a rehubbed Mercruiser cupped stainless 15" prop.....maybe should have stayed with 14", but the entire operational characteristics of the boat changed so drastically it was not funny, instead of hitting the throttle and engine winding up boat not going anywhere, don't forget I had a tow behind me too....I hit that throttle, they better have a GRIP now, that boat would jump so hard outta that water, I had to hold the helm...serious....

so, along about '95 or so, I grew weary of other issued with the '87 vette, sold it and bought my '72 vette, dead stock fresh L48 engine, Muncie 336 rear.....with the original QJ it got only 12-14 mpg and in winter only 10 around town...no fun....
so on went a TPI from Carlisle, and the mpg went to 24 on the highway cruising 80, doing some 4000 rpm, kinds tough on the engine, that was the configuration I drove from DC to Jax Florida, house/territory hunting looking to move from the land of ice and snow....

In a way I should have stayed with that setup...but NO, had to do a hotrod....so original L48 was removed/later sold, and in went a 355 roller engine, with overdrive automatic, which in '97 was the cheepest way to get overdrive into that vette....due to some ~120 hp increase, the car only gets a max of 22 mpg now...oh well....there have been many combos and heads, and inductions on there, all of them variations on the TPI, and several chip into the sock speed density GM 1227730 computer....

about 4 years ago I tried a Mega Squirt....but due to the Serial D connector and all the adapters needed, I could not find a functioning computer that would enable me to tune the thing, I gave up after two months battle, and went back to stock system...

I have had my issues with this '72 and the FI, but nothing inherent, just some water in gas, and injector sizing/types....the latest is a switch to a highly modded LT1 induction on the L98 setup....

IMO, after some 50 years of hotrodding, running anything from Holley to Carter WCFB, AFB, even 2 bbls carbs, seeing friends with Tri Power setups, even dual quads.....cross rams, Hemi's, old Pontiac 421, 389, 350 engines, and that 455 I modded above, the use of carbs is a thing of the past these daze....sorry, but I do have a slight advantage, in that being a olde tyme ET, I do have a goodly bit of test gear like my old Tektronics scope, DVM, audio oscillator, and Weller soldering station, which makes any silliness with wiring easy....I am however not much on programming computers...

so having said all that, the one thing I find missing from the above comments is that you can take the TPI stock manifold,and siamese the runners about 2.5" down the adjacent runs, and that allows a huge increase in rpm, while giving up very little in lo torque....SO I HAVE HEARD.....I never did it to my TPI's as I had a large runner system on there before going to the LT1 induction....

 

Why don't you take your car to a good tuner and see what they can do? First thing most of 'em I know will do is toss the Demon, they're notorious for poor quality.
All the dyno and real world stuff I've studied have shown the two to be very nearly equal. Sunset Racecraft sold several race engines with EFI that made very similar power to carb'd engines, the problem was that nobody wanted to take the time to learn to program 'em, so the boss spent a lot of his time handling them. A well set-up carb will deliver the same performance as a well set-up EFI. Check out the guys racing LS engines - the ones making the most power are on a carb, a good EFI system for bigger cubes or higher RPM racing has proven to be elusive at this point. Keep in mind that some of the best computer tuners in the business have given it a shot and can't beat the carb. Granted, a lot of it has to do with the lack of a decent intake with good airflow, but it is what it is.

If you're frustrated with a carb, you'll ****** yourself bald trying to figure out EFI. If a system is very easy to program, you can bet it'll be down on performance.

One electrical problem or computer glitch can leave you stranded with no idea where to start looking for the problem. Can't say the same for a carb'd engine, at least for most of us. We may still be stranded, but at least we can check the basics without a laptop.

Besides, they just don't look as cool as a nice carb setting on top of a nice intake, all the wires and plastic junk make 'em look cheap, IMHO.

 

I have to disagree:P FE is not limited to TPI & cheap plastics... chromed "trumpets" looking at me from under the hood don't look cheap to me! (and a whole lot cooler than a 4brl)