I have spent about a year driving my 340 Cuda with the LD340 & thermoquad. It is OK, but I really have the desire to switch to a fuel injection set up. I am totally fuel injection illierate and am hoping someone has done this swap and could walk me through all I need to know & do to convert from the carb to FI. I have access to a Mopar Performance MPI intake, but not really sure which one at the moment. The manifold is bare - no throttle body, no fuel rails, just holes where the injectors go.

Any help / advice / warnings would be helpful at this point.

Thanks,

A few comments based on switching a "B" engine to FI. A manifold made already with bungs makes it a little easier if you can find the right manifold for your application. The alternative is to get bungs welded into a carb manifold.

The main "ingredients" start with a high pressure fuel system. With a stock tank you can use a frame rail mounted high pressure pump. Most systems use a return style regulator in the engine compartment and return line back to the tank. You'll also need fuel manifolds and mounts plus a throttle body. Depending on what you have now, you may need a different distributor. Also on the list, several sensors (water temp, intake air temp, manifold pressure), harness and ECU. A laptop is needed for tuning and a 12V to 120 volt convertor is handy (from Radio Shack) if your laptop battery is weak like mine.

Depending on time and willingness to tinker you can get all this several ways. The easiest and fastest is to work with a dealer like Mopar Rich on this board or TJ Tracy at Advanced Performance Fuel Injection to spec out and assemble a "kit" and if necessary install bungs in the manifold. FAST and Accell both make good systems. A full kit may be over $3k depending on specs.

An alternative is to assemble your own "Megasquirt" ECU and pick up the other pieces individually.

For engine start-up you will get a generic program good enough to get her going then the tuning begins. Tuning was fun for me but also time consuming. Getting it to run reasonably OK doesn't take long but getting it dialed in close to "just right" takes some time.

Good Luck!

The MP intake is likely setup for the vertical mounting fasteners of the magnum head and won't bolt to your LA heads.

Yeah - I know about the vertical screws - but the bosses can be ground down and new holes drilled probably cheaper than welding bungs into my present manifold.

Thanks - I've been reading all about it !

FWIW, you CAN modify the Magnum intake to work with an LA, and you don't have to grind down the vertical shoulders to do it. You DO have some grinding to do, but you can do it in a way that you'll end up with an intake that will work on both types of heads:



IMHO, if you haven't already got a good set of heads (or domed pistons), you may want to take this opportunity to upgrade to some Magnum-style heads. That'll give you a bump in compression, better ports, and no need to modify the manifold...

Clair

I would like to jump in here if that is OK and add my question.

It seems like I have a somewhat similar setup: 344 with ported 302s with 2.02 valves. At the moment I have an Eddy Performer and a 600 carb. Still dialing it in on the dyno... I will have that motor on the dyno for the next two to three months and a lot of time to play around with it and work out the bugs.

I already have a distributorless ignition and want to go Megasquirt next. This motor must have some lowend-torque as it will go in my 67 Fury. Stripper car (no options except AC), nevertheless not superlight. Cam is Comp 264HR with 1.6 roller rockers, I may be Ok with going one step hotter. A500-trans (low first) with 3.23 gears (cannot go deeper... Germany... Autobahn...).

The only EFI-manifold I see is the Edelbrock 28155. This is a Super Victor thing, which seems totally off for my motor. I do not want too loose of a converter in my mainly street driven car, so I would like torque starting somewhat at 1500rpm latest. My stock hydraulic roller lifters will be done at 6000rpm, if there is a useful option I would upgrade, but it stays hydraulic roller. Is there a manifold out there with injector bungs for my application?

If it was carbed I would think the air gap is the way to go from what I read. Is converting an airgap to EFI a good idea?

Anyone having some real world experience?

Thanks
Flo

PS: reading Rich' articles... and his cookie recipe :-) hmmmm.... :-)

I have a very similar setup to what you are talking about, except it has a couple of turbos on it besides. My 302 heads have the 1.88 intakes, as the 2.02's don't really gain much with the flow available in the ports, and cost you a bit of velocity. I am much milder on cam with a 208/201 @ .050, and 1.5 adjustable rockers. My pistons are matched in shape to the quench pads on the heads and then dished at 8.25 to 1. Quench is at .038.

Your desire for good torque starting at 1500 may be tough with the combo you have, especially if you go with a big manifold. Even a Perf RPM may be a bit big, and it has the big ports comapared to the 302 heads. I am running a regular Performer on mine, and it matches the rest of the setup very well. I get excellent torque at 1500 at it will pull past 5500. I would stay away from any of the big single planes, even for efi. The better balanced flow from a good dual plane will work much better for efi (I know others will disagree with this). A regular Perfomer should be able to get you near 400hp without a problem.

I am running a FAST bank to bank system with vacuum/boost referenced fuel pressure.

Here is a pic of the Performer. I did angled injectors on it to try it out. Probably not work the extra work, and many manifolds don't have room anyway. This was before the adjustable rockers were put on.

I would agree with bank-to-bank injection. The pulses aren't timed to the intake valve opening. But run sequential - and you'll be fine!!!

I thought that single or dual plane should not really matter with port EFI. But as I said (and others seem to agree) the Victors seems to have way too large runners. Would a smaller single plane be the best bet? Like Torker intake?
I think the Megsquirt is not far enough to do real sequential injection. I would have to add a cam sensor anyway, running wasted spark with an EDIS-system at the moment. (runs pretty good by the way).
I would be very interested in getting a converted manifold from Rich. I CAN do the fab and welding... but if you already have all the jigs and the experience to get the angles right... there will be plenty of work left for me! NOt sure what is the best manifold yet.

Depending on how long that motor stays on the dyno I may think about forced induction too... 9.5 c/r might be a little high though.

I know booster likes his dual plane intake for port efi. Looking at the ports, their shape and size, I'm not a huge believer in the use of dual plane intakes for efi, but he says his real world results show they work. I picked up a port efi victor for my big block. I'll give it a try, if it doesn't perform well I can always swap it out for something else later on.

Quote:

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I think the Megsquirt is not far enough to do real sequential injection.

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Uhh, the megasquirt designers are beta testing the MS-2 Sequencer, megasquirt's sequential fuel injection controller. Probably just a matter of months before that unit hits the market...

You might want to do a search on the dual or single plane for efi as it has been discussed here many times.

The issue is not really dual or single plane as it applies to a carb setup. There the dual plane splits the pulses to give better signal to the carb, and obviously that doesn't apply to efi.

For efi, I like a dual plane because you can get them with much better matching runner lengths. To me that is one of the MOST important characteristics, if you are going to be making a steet car that sees a wide rpm range.

The arguement that is given for it not making a difference is usually that the injectors all give the same amount of fuel to each cylinder, so it has to be the right mixture. That would be true, except that the cylinders get different amounts of AIR, if the runners don't match. You actually get worse mixture matching, cylinder to cylinder, than you would with the same manifold and carb.

The next arguement is that if you run sequential with individual cylinder fuel trimming, you can tune out the mismatch. This is true, but only for one rpm range, as the trim puts the same percent change on the whole rpm range. If you take a look at the flow of a manifold with mismatched runners, you will find the mismatch in flow will be way different at 1500 rpm than at 5500. The reason is very easy to understand. At a particular airflow, you can have a short, small runner flow the same as a long, big runner, but at a different airflow the runners react differently to the change, and then they flow differently. It is essentially impossible to get a manifold with non-identical runners flow evenly over a wide rpm range.

I have tested quite a few manifolds, mostly dual plane, but also singles. I don't have the option of individual cylinder egt or mixture reading so I used plug reading to test. What I did was setup and run at low cruise 1500 rpm for an hour and stop and read the plugs. Then the same highway cruise 2500 rpm. Then the same after several full throttle full rpm runs. Once I compiled the data, it was extremely obvious that the closer the runners matched, the more even the plugs looked, cylinder to cylinder, over the whole rpm range.

Interestingly, the worst manifold I tested was a dual plane, the Weiand 8007. If you look at it, you can see why. It has the longest runners something like 5 times longer than the shortest. The best for match was the M1 dual plane, that is very similar design to the old cast 340 manifold. The runners tee and then go equally to their cylinders. Right behind it was the regular Performer. The best single plane was the Street Dominator, which performed very well power wise, but the mismatch limited mileage at cruise because the mixture mismatch caused lean miss. The best to worst manifold showed about 10% difference in fuel economy. The best manifolds would go 40K on plugs (cold ones because of the turbos), where the worst would foul some of the plugs in under 1K.

If you look at all factory efi intakes, you will see they are fanatical about matching runners. This is one of the reasons they can get such a wide, flat torque curve, long plug life, and good economy. They wouldn't do it if it wasn't important.

I will try to scare up some manifold pics that show the runner lengths. It is pretty interesting stuff.

Daytona, I just recently finished a Torker and a RPM for a 383 a friend is putting together. NA for now, turbos later. Hopefully, he will be able to do some testing of them and give some feedback.

Here is the Weiand 8007. Look at the length of the runner to cylinder 5 compared to cylinder 8.



Here is the M1 dual plane. Note how the runners head to the center of the manifold and then tee back to the cylinders to keep them even.


Here is a regular Performer. The teeing is less obvious, but when you measure the runner length they are very close to the same.


Here is Performer RPM. Also pretty well matched.



This is a Viper manifold. Very typical of the modern intake designs.



Daytona, this is the Torker I did.

I understand your line of thinking booster, but some of the dual planes out there have horrible air distribution between cylinders even though they have equal length runners. But the same holds true for some single planes as well, some have pretty equal length runners but obvious terrible air distribution between them. Some you can tell easy by looking and feeling, others not.

IMO it comes more down to the specific manifold in question rather than broad generalizations between single planes and dual planes.

Daytona-There absolutely are better and worse within each catagory, look at the 8007 above, but from what I have seen in my testing, the runner match is, far and away, the best predictor of flow balance over a wide rpm range. What dual plane with equal runners have you seen that has bad airflow matching? I would love to see it and try to find out why.

I don't say that it is a single or dual plane issue. What I say is that you can't find a single plane with runners that match very well in street rpm ranges, but you can find well matched dual planes. If you could get a single with matched runners, it would be fine. A lot of the factory efi manifolds are single plane by definition.

One thing that you have to remember is that I am testing with efi. In particular, a single plane could give horrible distribution on a carb, but much better on efi, because single planes are famous for bad distribution because of carb signal and cylinder robbing. The Torker in the picture above will probably be fairly well balance setup, based on the runners, but it is way big for most street applications. You will give up an awful lot of bottom with it. I did not test anything anywhere near that big as I am in the lower rpm ranges on my engine.

So what I am saying is that you can't go by how the distribution is with a carb and apply it to efi. Besides the carb signal issues, you also have wet/dry flow to consider, but as with any flow, if the runners are the same, they will flow the same. Also remember that matched runners not only should match length, but they should be the same crossection and shape, with similar turns. The further you get away from a manifold like the Viper one shown, the worse your mismatch of flow over rpm range is going to be.

To accurately evaluate the individual manifolds for efi, you have to actually test them with efi and keeping other things equal. You can't go by anything learned with a carb.

I would love to see complete testing of any manifolds to see how they did, if anyone has them.

If you are stickler for definition accuracy, the "dual planes" that I use are not really dual planes as I always totally remove the divider, which is there to improve carb signal and only hurts me.

Rich, you will notice in the next paragraph I addressed the individual cylinder tuning. Unless you can do it to do a different % at different rpm for each cylinder, you can't correct for a bad manifold, because the mismatch changes with rpm.