I've been tossing aroung the idea of FI in my head for a while now. I can work over a carb pretty well and make it do what I want on general terms, but it's still a mechanical device and limited as such.

Where I have highest vacuum, I need the least fuel in typical driving. A carb feeds fuel best at high vacuum. At low vacuum high load, when the most fuel is needed, it has no draw. I have come to understand this and make it work for the most part, but FI really should work better.

I work on modern cars for a living and have good understanding of the factory systems and how they work. I've also read up on most of the aftermarket systems for V8s.

I'm looking for a number of specific features that I have not yet found. Maybe somebody knows of an existing system that I've not run across yet or maybe my plans are just a waste of time.

What I'm looking for is an individual runner system with no common plenum, that is able to sequentially fire the injectors and monitor each cylinder individually. Basically run it as 8 individual 1 cylinder engines. It can't be impossible, although I may have to build it myself. Cost may be the reason no such system is mass marketed but that doesn't stop me from looking.

I saw an individual runner -type system from FAST in Super Chevy a couple of years ago now, but each bank was monitored, not on a cylinder-by-cylinder basis. With each port having a different shape and different flow characteristics, I want the ability to tune each for it's own best. Yeah, you could call me anal-retentive:D

devin

I've tuned a couple "IR" intakes. You don't need individual cylinder fuel control as it is pretty much perfect with that design. If you want to be guarantee it, get a set of dynamically flow matched injectors. I had 8 widebands on these engines so I can say this.

Then spend time syncing the plates. The hardest parts is getting the banks mechanically synced. Get a ECU like a Holley Dominator that has 2 WB02 inputs so you can monitor and adjust.

You are looking at 5k minimum. They work very well when mechanically adjusted right.

Factory GM LSx engines have almost perfect cylinder to cylinder airflow at all operating conditions.

You don't want to treat cylinder distribution issues with the fuel control, it is too dynamic, you want to fix it with using the right intake in the first place. An IR, when adjusted right is about perfect. A tunnel ram with dual air valves is also very good for a plenum intake.

You might look at this stuff. This is an EFI setup that looks like billet downdraft Webers. It's essentially a IR setup but he runs a small tubing connector between the throttle bodies so he can use a MAP sensor or vacuum advance. These is a very finely tunable setup on sync'ing the throttle plates. I'm familiar with this stuff, the guy that makes it is a friend from back in the 70s. This is top quality stuff, show quality and not cheap. The cars that have this are some of the best running cars I've ever seen or driven.

http://imagineinjection.com/

Thanks guys for the input.

Doug- I am comfotable in the use of a Uni-Syn to sync the banks. I can't see anything needed more than that, but I could be wrong.

I own an Innovate LM1 that I can monitor with already, but I'd really like an adjustable feedback system. I just recently read the thread on the Corvette with the Holley system (can't remember his name right now) on it and liked most of what I saw other than the common plenum.

While an LS series engine has wandered through my head now and then, seeing how much power guys are building with them, the root of the matter is I'm a big block guy and always will be.

Tom- I've saved your link. That's the kind of setup I have in mind.

No matter what I do, I know it won't be cheap, but no truly good induction system is cheap.

Devin

watch your throttle body sizing on an IR setup. There's no common plenum to "borrow" air from, so what that throttle body/runner flows is all you get. In other words, no use having heads with intake ports that flow 375 cfm and a throttle body on top of it that only flows 300 cfm.

I did a 400 small block IR setup with (8) 2 3/16" blades (Hilborn) and with some good small block heads I still had 2-3 inches of vacuum at WOT. Heads flowed like 315 cfm and that throttle blade (even though it's larger than a Dominator carb blade) only flowed 280 cfm or so. That's the big drawback of the Imagine and similar systems, you can't get a large enough blade for a higher hp build. Maybe they offer larger now, but when I had mine there was nothing available that would support much more than 600 hp or so.

They do run fantastic, tons of torque, and looks that are un-matched.

Hmmm...that's an interesting dilemma. I was of the understanding that I would need to size the throttle blade approximately the same size as my intake valve. Guess I'm looking a bit bigger.

While I do race my car and hp is always more fun, my real goal in this is driveability and economy. My purpose in persuing an IR system is that it's not sucking in an exhaust diluted pulse from another cylinder at low speeds. I won't deny that I love the look of stacks, there's just something bad-ass about it, but I'm much more of a sleeper kind of guy. If I could get the response, driveability and economy out of a carb that I should out of a good injection system I would slap a Q-jet on there and be done with it. Judging by the times I'm running, I'm at approximately 420-440 hp at the rear wheels. I figure that translates to close to 500 at the crank. I'm in the midst of another project, but when that's done I'm expecting to make another visit to Wolfplace with an expected 600-650 at the crank when we're done. Time will tell. In any case, I will need something that will support that level and potentially more without restriction.

Devin

Wow, Jody, you've had an Imagine system? I've never run into anybody on the forums that had one. I rode with Bob in a 427 Cobra a couple years ago, it was freakin brutal. Felt like an engine with a roots blower, instant power. I heard the guy was getting over 20MPG on the road with it.

Wow, Jody, you've had an Imagine system? I've never run into anybody on the forums that had one. I rode with Bob in a 427 Cobra a couple years ago, it was freakin brutal. Felt like an engine with a roots blower, instant power. I heard the guy was getting over 20MPG on the road with it.

no Tom, I had a converted Hilborn setup. The setup pictured below had 2 3/16" blades and was still too small for a 400 cid small block. I've seen and dynoed the Imagine systems with a Cobra EFI tuner guy I used to help out. Nice stuff, but many don't realize to watch out for the airflow on the blades, at least in a higher hp setup.

You're right, they are smooth, tons of torque. Pretty much all the IR setups when tuned correctly run fantastic. I know on a 500 cid Ford Cobra he picked up 65 rwhp by removing the Imagine setup and going to a single four barrel throttle body, no other changes. It was purely an airflow issue. Again, that was several years ago, maybe they have larger tb's now.

http://www.camcojb.com/pastprojects/cobramotor.jpg

The BBC I just tuned, we did a back to back on the dyno against the dominator and single plane. The EFI matched peak power (1080HP) and made more torque down low. As Jody says, purely a throttle body size deal. In the car (this is a super comp dragster), the system has run flawlessly and zerox's timeslips and is predictable.

Doug- What kind of injection was used on that?

devin

Holley Dominator EFI

Doug- little more info? IR body maker, throttle blade size? How many ci?

Thanks,

Devin

Hilborn, 600ish CI, Can't remember the throttles, might have been 2.5 or larger. I'm headed to the races today and he's there so I'll ask.