Fuel Injection

[ray fenti]

The amount of information on this website is overwelming, buy I have not seen any questions about using fuel injection instead of a carborator. I assume that is because most people want to replicate the origional. Is fitting a modern fuel infection in a small block ford a good idea for someone who is not so much insterested in being historically correct and is more intested in performance? Also, from some of the pictures on the ERA website, the electrical system looks like it also replicates the origional. How about using a modern fuse panel with relays mounted inside the car instead of open fuses that look like they are mounted on the firewall in the engine compartment? Thanks. Ray Fenti

[Bob Putnam]

Ray,

I think there are a couple of our cars with FI, but I haven't seen them personally. There are several systems available - I think that there's a recent thread on Club Cobra discussing them.

As with most things you get what you pay for, and most require some tweaking to get just right - especially if your engine is modified. The cheapest system will probably be $500 more than a single 4bbl carb. We tend to stay with the simplest system possible - we don't even use a choke. With the right technique the car still starts instantly, but may require a minute or two of idle time before smooth drive-off.

Having had cars with both engine compartment and underdash fuseboxes, I much prefer not having to crawl underneath the dash. I'm not as limber as I used to be. There are circuit breakers that will fit in the AGC fuse mount, if that will help!

[skeeter]

Ray,
I have holley's fuel injection system on my 427. It is the holley 950 commander system that you can see in a Summit catalog. It is not a true throttle body fuel injection, but it does have a very tunable computer module that you can tune with your lap top. I am pretty satisfied with it and have spent a couple hours on the dyno trying to get it dialed in. It does give you instant throttle response and possibly better fuel mileage. The only thing that does not look stock about it is all of the wires coming from the ecm to the injection system.

David

[scott cooper]

i have been using holley TBI for 10 years never touched it yet, although i used the analog system easier to set up

[dlampe]

I have personally never seen any test to prove that fuel injection increases performance over a 4 barrel or a tuned set of webers. Drivability, yes but not overall perforance. Does anyone have these results?

[ENTDOC]

there was a great article in Hot Rod a few years back on that subject. In the end the carbed unit made more power than the EFI but as expected the fuel economy was better on the efi.

[thorconstr]

I've had TWM injection on my 427 going on 4 years now. Although I wasn't looking for fuel economy, I checked once and found that I get 12-13 mpg and that's with my foot into it most of the time. The computer is under the dash, and I also s-canned the useless Lucas fuse panel for a modern fuse block that's not obtrusive. The engine put out 717 hp @ 6500rpm with 680 ft lbs @ 4600rpm when dynoed while being built by Keith Craft, enough to scare hell out of me and make me vow to sell it, but after 2 weeks I was looking for ways to make more hp. Other than driveability, and performance, (the response is immediate and builds thru the rpm range) the wow factor when the hood is up is amazing! I've driven carbureted cars and they don't seem to pull as hard, that's not saying that there are not some that do! I like it so much that I became a dealer for TWM. It's not cheap, but neither is a Cobra!
You can click on Thor Motorsports in the advertisers column for more info and pictures.

[eschaider]

Ray,

I think it comes down to a matter of control and tunability. The electronic fuel injection gives you both in spades. Unless you are very familiar with things like emulsion tubes, air bleeds and venturies you will be at a disadvantage replicating the tune you can quickly come up with for your engine with electronic injection and your laptop.

From a power standpoint I am not persuaded the injection outperforms properly set up carburetors. From a cold start and cold weather start standpoint the injection is clearly superior. In terms of A/F ratio maintenance electronic fuel injection has no equal which is why Detroit went that way to meet federal emission standards. An interesting add-on benefit is potentially better fuel mileage.

The engine's dirving manners will improve somewhat if you have a large cam because the fuel delivery will no longer depend on a weak vacuum signal at low engine speeds. You may also discover that you pick up a couple hundred of additional usable rpm at the bottom of the RPM range. Always nice for highway cruising if you have one of the overdrive 5 or 6 speed units.

Ed

[289FIA]

Originally Posted by ray fenti

12-10-2001, 07:08 PM

All great info pertaining to EFI... I'm still deciding which way to go.

Not sure if Ray Fenti's still interested. Check out the posting date

[SantaFe66]

I have read that there is a difference in the sound of a running FE with Carb and EFI. The opinion was that the Carb version sounded "better". Can anyone comment on that?

I would expect that EFI makes a smoother running engine but I suspect it depends on the level of performance the engine is built to. An engine with a big, flat-tappet, solid lifter cam would be difficult to hear any "smoothness" over the racket.

Anybody have any experience with this?

Paul

[DonC]

Did a Mass-Flo EFI installation last winter on my 428 FE and got a season on it this summer (about 7,000 miles). Very pleased with the driveability of the setup and it's performed without a hitch from sea level to 14,000 feet.
Put the car on a chasis dyno before I took the Holly off and after I put the EFI on. No significant changes in power or torque but the curves for the EFI were considerably smoother.
Minor early teething problems but they were immediately and correctly addressed by Chris at Mass-Flo. Very easy to talk to and knows his stuff.
Looks pretty much like a carb but with fuel rails. Very complete kit, nothing extra needed.




DonC

[Jim Holden]

As to the wiring on the firewall... that's where the original wiring/fuses were. ERA has the (from my perspective taken the correct) perspectieve to try and replicate the original "look." Certainly, anyone can "street-rod" their car, but (again) in my opinion that will depreciate the value of the car when that day comes that you want to sell it and move on to something else.

Jim

[Calbullet]

Don, just a quick question? where did you mount the O2 sensor. on the sidepipe or somewhere on the header pipe. can you take a picture if possible.

Thanks
Mel

[DonC]

Mel:
Went round and round with Chris about the placement of the O2 sensor. He (the instructions) call for it to be mounted within 18" of the manifold/exhaust port. Given the primary pipes are in the neighborhood of 30" long I wanted to mount in the collector but Chris was adamant about the max of 18". As a result mine are mounted in the #1 and #5 primary pipes about 13" from the head. I had to port the driver side heat shield to clear the top of the sensor on that side but the passenger side had enough clearance. This was due to the shape of the primary pipes not a fault in the design of the Mass-Flo.
This past Sept. I spoke with a fellow who also had the Mass-Flo system and mounted the O2's in the collectors. He indicated that the system ran very poorly until he relocated the sensors at the recommended position. It seems that even though the sensors are heated there isn't enough heat at the collector to get the required signal.
I discussed the fact that mounting in the collector would give a more accurate reading of all the cylinders rather than just one and it appears this is secondary to the heat issue.
As I mentioned above the system works very well with WOT closed loop air/fuel right at 12.5:1 and closed loop at 13.5 which is a little rich but necessary for the cam I'm running.
Sorry but no photos of the primaries with the O2's installed.
DonC

[Calbullet]

DonC, thanks for the reply, answered my question perfectly. O2 in collector would not work for me, just could not find a easy solution to the mount, will look into the primary pipes

Mel

[RICK LAKE]

Calbullet I am running a wide band FAST system. As long as the O2 sensor is at around 800f you should get a go O2 sensor reading. You should mount the sensor in the collector where all the exhaust meets. This way you get the average gas from all 4 cylinders and not just 2 cylinders. Some FE cylinders run leaned than the others. I have my O2 on the inside of the pipes and at a small angle going up. It should take 2-3 minutes to get enough heat to the sensor to start varying the readings of lean/rich. I do have my header pipes rapped to keep the heat in, they are hot coated also. This may make the differents in heat range of the inside exhaust gases. Rick L.

[wrench87]

a wide band o2 sensor runs a lot hoter then a factory narrowband, so it is ok to put a wide band in the collector. the narrow band has to run around 18 inches from the cyl head. when i was running my 4 into 4 headers i mounted my factory o2's in the 2 rear pipes wich worked out fine.

[fkemmerer]

You'll defintely want to get an EFI system with a Wideband O2 sensor as it will help you a great deal in tuning the car. Its probably best to run a Wideband O2 sensor (WB02) and to put it in the collector area of the header. Many experts recommend the passenger side collector (because the passenger side bank on some engines runs a bit leaner). This way the sensor can read an average of all of the cylinders on one side of the engine as opposed to a single cylinder. Its also best to mount the WB02 in the top 1/2 of the collector if possible so you can to avoid potential problems with condensation on the sensor. I'd also recommend that you install a system with a full set of sensors and controls including an Idle Air Control Motor. This can involve some extra initial expense to modify the intake manifold on stack systems like the TWM but it allows the EFI computer to do a much better job regulating idle and other transient throttle charateristics of the motor. Attention to proper prepartion of the electrical and fuel systems is also important if you are to create a trouble free EFI setup. Check out the following thread for a good discussion of what's involved in EFI:

Stacked EFI- advise/thoughts and poll.

I am in the process of installing an EFI setup on my ERA and I'm running EFI on a blown and injected (EFI) street motor on another car at present. I would highly recommend an EFI setup if you don't mind the cost. Its defintely extra $$ and work to get EFI setup installed on a car but once you've got it there, you'll be rewarded with a much more drivable setup than you'll get with carbs on the same engine.

Here's a picture of the Ford FE motor that's going in my ERA (482 ci - 650+ HP on pump gas):



And here's a picture of the engine that I'm currently running with EFI in a different car:



The later motor is a good example of why you might want to consider EFI. The motor in this picture makes 625 HP on pump gas and is completely streetable. It starts and idles like a stock motor (even in cold weather) and it makes a great deal of torque and HP when you open it up. Your ability to properly tune an EFI equipped engine (even a radical one) is much better that you can achieve with carbs. Also, street drivability and throttle response will be better, especially with radical cams, etc.

The computer control that comes with an aftermarket EFI system also opens up some other interesting possiblities. For example, FAST's computer can support electronic traction control. With the addition of a driveshaft speed sensor, the computer can sense when the rear wheels are spinning and it will selectively cut timming and fuel to individual cylinders to keep the rear wheels from spinning excessively. This should be great for cars like the 427 Cobra where applying the torque from a big block is a real challenge. We're going to try this setup on my ERA. Most modern EFI computers have other features that are useful such as power adder controls, boost controls, data recording features (very useful when you are tuning or are trying to troubleshoot problems), etc. You will also gain tremendous control over the details of your motor's operation. For example, blown motors such as the one above are prone to getting hot when they idle for longer periods of time. This is because of the load that the supercharger places on the engine even at idle. For the motor shown above, I was able program the EFI computer to slow the idle speed to about 700 RPM when the water temperature rises above 195 degrees which causes the motor to generate less heat. This motor would not normally idle smoothly at that RPM unless it is fully warm given the camshaft that is installed. This was a great aid in keeping the car cool in traffic.