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Fuel Injection



I take it that Chris will probably be most knowledgeable in this field. First off, let me say that at this time I don't have any type of unit figured into the near future for my '71. I know that Chris has commented as to why he chose Edelbrock, but I'd like to know if anyone has tried the Barry Grant VFI, Accel SuperRam, Holley's unit or any other set-ups. I once read that some guy took a 454 and rammed into a C4, but had clearance problems so he took the Accel manifold and cut it down to fit. Since the motor made plenty of power on the dragstrip, I figure there weren't many problems by shortening the runners. I think this(long runners) was a problem of the TPI units? However, I know that many aftermarket manufacturers still use this configuration. What are the downfalls of each fuel injection method? Is there any one that is superior? The Ramjet 454 that Chevy released seems to be quite tall and perhaps not as effective as the LT-1 variant that is eqipped on their small blocks. Also, Chris could you share your fuel line sizes and how they were determined? I have more questions, but will stop right now, so it's not too much at one time.--Bullitt

Like I said before, for street application the Edelbrock system has them all beat. However, you should investigate every system out there for what works best for you. For example, if you enjoy doing your own tuning and have a good quality lap top computer, you may want to look into some of the more exotic systems. Most people forget to add that little jewl into the equation, and after buying the EFI set up, they have to go spend $2K on a lap top and extra soft and hardware to program.

Fuel lines are pretty standard for all the systems. Mulit Port fuel injection works off of high fuel pressure. It is not so much volume as it is pressure. Therefore, the size of the fuel line is not as important as you might think. Edelbrock spent much time with me discussing this because I could not imagine feeding 550 hsp off a 3/8" line. They had to change my thinking. You will need at least a 3/8" hard line to and from the system for pressure feed and return. Most guys just plumb a soft line from the tank pick up forward for the feed, then use the original feed line as the return. The 5/16" original return line is too small for the volume of fuel that has to get back to the tank quickly. Edelbrock claims they run up to 700 hsp off of 3/8" line on the Pro Flo EFI system. Keep in mind, hydraulics and systems under high pressure are a different world than carbs attempting to suck low pressure high volume.

I ran three fuel lines. Two 3/8" hard lines. The feed line is aluminum with thin walls for maximum volume. The return is just a 3/8" steel. I also ran a 5/16" line as I plan on mounting a vapor can in the right rear quarter (does not come with the EFI kit) to cut down on any gas odors.

Car Craft did an excellent article on EFI a few months ago that went into great detail on those using Mass Air Flow, and Speed Density. Mass Air Flow systems are the ultimate as they are real time and calibrate for variables on their own. The majority of aftermarket EFI systems are speed density. Which means that the computer has to be given a entire preset chart of values for a given situation that matches the engine and atmosphere combo. While still superior to a carb (for most of us that don't know how to tune carbs), it will never have the total flexibility and driveability of a 2001 Vette that uses a more sophisticated system with Mass Air Flow. This is also why I choose Edelbrock. They have been there done it with the same engine combo and dyno tests. I am satisfied with the reported results of 550 hsp or so. With that thinking, I duplicate what they have done, take tons of guess work out of it, and reduce the amount of time it takes to get the system optimized.

The fuel pump gets mounted low near the tank as it will kind of gravity suck feed to the pump, then get pressurized up the line. You put a filter before and after the pump. The EFI systems come with all the parts you need to do this.

Okay, the RAM JET style, and Accel Ram etc. create a real problem for Sharks. They put the throttle body just above the water neck at a position too high for our hoods. You need to consider systems that put the throttle body where the carb would normally go.

I am still going to have some problems, as the Edelbrock system uses the Patented Air Gap manifold. Great to keep the air cooler, but creates hood problems. I should be able to squeak past because of the L88 hood. Plus, the throttle body is smaller than a carb since it only meters air, the fuel is delivered by eight seperate injectors mounted on fuel rails just a like a stock system.

Most aftermarket EFI guys will build the EFI system on the manifold of your choice. So, if you like yours, and it has good hood clearance, you can send it to one of the dozen different companies that will machine it for injectors and sensors.

Finally, remember that Port Fuel Injection does not work off the same concept as a carb when it comes to the make up of the intake and port configuration. The fuel is blasted right into the cylinder. Benefit is, you can run an open plenum (normally high RPM only carb manifold) with EFI and still get low RPM performance.

Shhhhhhhhhhhu, my fingers are tired. My EFI unit should be here soon. Of the items I ordered, it was the only "not in stock" item. The heads, cam, pistons, etc. should be here this week. I will of course up load pics of Christmas in October when they get here.
More Questions...

The only reason that I mentioned the Super Ram was because of the article I had read. I need to look through my Vette magazines, but I know the issue came out in '98 and the shop was in San Diego, who performed the BB C4 set-up. They ended up cutting around 3 inches off the manifold to chop it down under the stock hood. There were many other modifications to be sure. The guy used an aluminum block and aluminum Edelbrock heads, which is lighter than the LT-1. I can't remember the exact figures, but he was putting around 400hp at the wheels. It's a pretty cool idea to hook up a laptop, which I have, and select a map for my engine combination. Designing certain maps for your specific application would be even better. One day, my '71 will get fuel injection, I promise. This brings me to my second question. Have you determined a location for your fuel pump mount? I want to put mine in a safe place, away from any damage should an accident occur, but as close as possible to the tank. I'm using a Fram filter that I will run ahead of the pump. Second question is, did you consider a fuel tank mounted pump? I remember a Chevy mechanic telling me that if you constantly run a low fuel level, the inner pump will burn itself out. I have some more questions still, so bear with me. Also, if anyone knows of a website or a good book that isn't too technical on fuel injection, let me know about it. Thanks Chris. :gap --Bullitt
For port fuel injection, the fuel pressure has to be pretty high, vs. Throttle Body. Therefore, they suggest mounting the pump as close to the tank as possible to keep the line charged.

I will be mounting my pump on the right inner frame rail. Since the car has sidepipes, there is no heat concern or worries of that nature.

At this time, I am still undecided if I will use a fuel cell or stock tank. The stock tanks on the old sharks are very dangerous (no bladder/baffle). The fuel pump is the least of your worries in a major rear end collision. There is nothing to prevent the tank from rupturing and sloshing fuel all over the occupants. I guess you could always mount a Ford style motion sensor into the pump circuit. These will shut the pump off in the event of a rear end collision. In fact, that might be a great idea for me to consider, I am glad you brought it up.

An in take fuel pump has one primary benefit---less noise. I have considered the possibility of getting the fuel pump and sending assembly from an 84-96 Vette and seeing if it will drop in the top just the same on the 69. Then again, the Edelbrock system comes with the external pump matched for the system.

Try these sites:




Haltech is the one to check out if you are really into tweaking your own software. They build the computer, you pick the engine and make up your own fuel/spark curves.

It is a wise idea to mount the pump below the tank for the reason you mentioned. This means, less you run out of gas, that the pump has a gravity feed of fuel on tap at all times. Most new car manuals suggest keeping 1/4 tank or more in the car at all times. This keeps the pump submerged, and the fuel surrounding the pump helps keep it cool and to live longer.

I saw a web site where a fellow installed the Holley EFI on his 454 BB. He used an automatic transmission mount to bolt to the frame, and then the fuel pump to the mount. He felt this would reduce noise and vibration. I have talked to two fellows with the Edelbrock pump that told me it was not noisy like the Holley.

Remember this, if it is external and it fails, it may be easier to service on the side of the road.
Gas Tanks

Chris, I know that Carter makes an insolation mounting kit for fuel pumps. I'll look through my catalogs for the part number. Turning the topic to fuel tanks, I share the same concerns about upgrading to an internal bladder system. I would think that they eventually deterioate, so is buying an used one unwise? I'm not sure how a person could determine the condition of one. In the somewhat conterversial Q-Jet post, the subject of fuel slosh came up. It concerned the float bowls, but I'm aware of baffles that can be purchased for this problem. I believe that the fuel slosh problem really stems from the unbaffled stock fuel tank. Taking a corner at speed and seeing the fuel level gauge go down, is proof of this. I'm aware that road racers use baffled tanks (it helps weight distribution and cornering performance), but don't know if they incorporate bladders, also. What are the advantages of the fuel cells that you are considering? Are there any with the same capacity as our stocker? Thanks for the websites links, as I guess I have some reading to do. I really appreciate you sharing your knowledge. :) --Bullitt
For those interested, I found the Carter Quiet Pump Pack in Jeg's catalog under part #CAR-18-14U. The 454 C4 conversion article is in the August 1998 issue of Vette magazine. The place is called, The Corvette Shop/TPI Performance Center in San Diego, CA. The guys who performed the extensive modifications are Larry Hofer and Dave Stanley. They removed 3 1/2" from the runners, so that it fit under the stock hood. With slicks and an all-aluminum engine, it ran a 11.49@120.29mph. They were having tranny problems, going through two in no time at all. --Bullitt

I have not made my mind up on the tank. It is true that a pure racing fuel cell can go bad over time. This also has much to do with the kind of fuel usually found in a racing tank.

The 69 coupe race car that I painted last year had a fuel cell installed. It was a nice bright red unit and required some minor mods to the mounting brackets to get it in.

I don't see any benefit in buying a used one as new ones are not that expensive. Yes, you can get comparable capacity, if not more in a cell. Some use actual stock style baffles, and some use a foam type substance to keep the slosh down. I plan on doing a little autocrossing, so the baffles would help.

11's are fast, but kind of sad when you figure a fellow with an ex highway patrol 5.0 stang and a few simple mods can run low 12's. Then again, 120 plus mph in 1/4 of a mile is pretty sweet.

Is that the car they were calling the ZR2?
Is that the car they were calling the ZR2?
They didn't have a specific name for the car, but the article was called Monster Mash. I mentioned it mostly because it dealt with big block fuel injection. They seemed to have power transfer problems through the use of the stock 4+3. They also used a Camaro computer, claiming it was faster at computing for the conversion. Onto the main subject, though.
some use a foam type substance to keep the slosh down
I heard of an external, non-flammable foam insulation to surround and protect the tank/cell in the event of a crash. I would think that racers would have access to this stuff. I'll see what I can find.
For port fuel injection, the fuel pressure has to be pretty high, vs. Throttle Body
What pressure are you going to have to run? What cam or how radical can you go? I know that you bought a Pertronix kit, but are you going to use an ignition box? DUI makes a HEI tach drive distributor, but it's fairly expensive at $500. Are you using a closed or open loop system? I know, I know... a lot of questions, huh? You should hear me discuss the topic of aerodynamics! :L --Bullitt
I installed the Holley multipoint system on my 71 454 a few months back. I'm very happy with it. Turn the key & go. No worries about choke, etc.

I used a tranny mount for the fuel pump and it is completely quiet.

I looked at the edelbrock system, and felt I preferred a laptop as it is nice to be able to view the complete fuel map on one screen, plus it also shows real time data for O2, rpm, coolant temp etc.

The Holley system lets you enter any data you want for fuel & spark. No PROMS like the edelbrock system.

It also has provisions for Nitrous if you want that. It will control nitrous solenoids plus richen the mixture.

One drawback is that it is batch fire only (no sequential), which really doesn't matter to me.
Also, it cannot use a wideband O2 sensor, but at $700, I'm not sure I would have paid for one anyway.

Oh, the holley will also plug into a GM knocksensor and you can let it retard timing when it senses pinging. Pretty nifty.

Let me know if you have any other Q's.
That is the great thing about having different systems out there. How radical of a cam? Well, remember, I am building a "clone" if you will of the Edelbrock package. The Performer RPM is pretty radical, yet very streetable.

If you want all the flexibility in the world, you would need the programable systems so you could match up to whatever cam, etc. that you want.

The fuel pressure will be high. Much like a stock 85-01 Corvette. I would guess there will be up to 60 psi at the rail. Zwede can better tell you as I am sure he has put a gauge on his system.

I like what he is doing. Very nice clean set up.

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