I have an 82 Fleetwood Brougham that I am pulling out the 4100 and replacing it with a 425 from a donor car. I plan on beefing up the 2004R and just a stock rebuild for the 425.

I would like to keep the fuel injection.
Are there any suggestions on making this combination work?

I don't think the FI system from the HT4100 engine will transfer to the old big block 425. Your best best would probably be to get FI parts from a donor big block engine, say the FI 368s from '81-84 limos or even a seventies FI systems, but I don't don't how reliable an FI system of that vintage would be. You could always get one of those conversion kits off the internet, though. Pricey, but guaranteed.

Greg

There's a lot of info around here about the swap - it's simple. Keep the donor car around until you're done if you can. Just use all the accessories, fan shroud, etc. I happen to have dropped a 425 into my 84 Fleetwood today. Using Ape Man's advice I redrilled the flexplate to fit the smaller 200-4r TQ converter, and made horseshoe shaped washers for the bolts (or for $95 you can get an SFI approved dual pattern plate). The TBI on the 4100 is laughably small - some advised to try a 454 TBI unit or stock 425/368 TBI stuff, but I chose to stay 4bbl. You MUST make all provisions to accommodate the TV cable on the tranny - it must be adjusted accurately and cannot be omitted.

Why not a TBI 305 or 350?

I thought of transplanting a SCB and 7004R from a 90s pick up truck or full size car and it had some pros and cons as well. What it boiled down to is I came across a 79 Caddy RWD donor car with the 425.

Transplanting the 425 and beefing up the 2004R are straight forward for my planned project. It is ironing out the problem of keeping the car fuel injected.

I am not familiar with fuel injecting a 425 with an 82 Fleetwood computer. My thoughts were to upgrade the computer, use a throttle body from a TBI chevy (350 or 454) a TBI to 4bbl manifold conversion plate and a distributor from a TBI 368.

Would anyone have feedback on this recipe? Suggestion, insight?

Factory fuel compukers have severely limited tuning range. Better off with a Megasquirt. Plug that into Google.

Factory fuel compukers have severely limited tuning range. Better off with a Megasquirt. Plug that into Google.That's not entirely correct, at least it depends on which computer you are using.

I'm using an embedded lockers system from http://www.dynamicefi.com. Bob is the man. It's a modified GM TBI ecm with a lot of excellent add ons. It's similar to the capabilities of Megasquirt II, though it is set up a lot better for TBI. It can also operate in MPFI mode in case you decided to switch later on though at that point I might recommend Megasquirt.

Another one I have used in the past is the '8625 ECM from the TBI L05 trucks. With this ECM you can control a 4L6xE electronic transmission, and still operate the TBI system. This opens you to all sorts of options with the aftermarket.

If I were you I'd get the ECM, coils, sensors, etc. from a modern LQ4 or other LQx engine. They are well supported and could be made to handle a large Cadillac engine with unmatched efficiency. I'd have done this had I known I'd be working on the 383 stroker in my car for so stinking long...
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1981 Pontiac Firebird Trans Am Turbo - LS1/T56
1993 Cadillac Fleetwood Brougham - 383 Vortec/4L60
1993 Mazda Protege LX - BP-ZE/G25M-R
1994 Mazda Protege DX - B8-ME/F25M-R

I still wanna drop an LQ4 or LQ9 in place of my LT1. I love the LT1, great engine, but seeing what I have come out of a LQ4 or LQ9, even the 4.8L and 5.3L or 5.7L, is amazing and worth the effort.....

It will happen one of these days....

To The Ape Man

How would the Megasquirt system be set up for the 425 in the 82 chassis?

How is evolved in this set up?

Not very evolved. It isn't NEAR as refined as a factory GM computer.

Personally? Adapt a late 80's TPI 350 Speed Density computer. That (at least to me) would easy. The MSII is ok, but not near as user friendly or refined as a GM TPI computer.

And cost of the TPI setup should be much cheaper IMHO...

Last time I looked, the car in question was a Cadillac with a Cadillac engine going in. Since the car is a has DEFI, a lot of wiring work needs to be changed no matter what. The thing about Megasquirt is that it can be adapted to many different types of fuel system hardware. You won't be stuck buying an entire setup. If you are lucky enough to find an old port fuel injected 425 or 500 intake manifold, that can be used. If not a throttle body can be fitted atop your 425 intake with an adaptor. I like flexibility in any proposed system. Port systems will require a totally different fuel pump with different lines. Sticking with TBI would be cheaper. You could even drop a 368 F.I. manifold and TBI on to the 425. Port sizes are smaller but it would work. A lot depends on your budget and skill level. If you plan to farm this out then it will be very expensive. Start up the search engine. There was one person on here who has actually completed a similar project. IIRC it was a 500 in a jet boat. Also try Googling for Cory Heisterkamp (SP?). IIRC he had a Megasquirt on a Cadillac engine.

A friend of mine has a MSII in his 03 Bonneville 3800 and it does ok, nice that he can tune it himeself, but simple things like idle are very poor. It doesn't work like a GM idle circuit. He uses the stock PCM to shift the trans, and the MSII to do the engine. Pretty nice hybrid system he has going.

The reason I suggest a TPI, is the Cadillac DEFI setup should be easily adapted to the TPI computer, and you get a computer that is tuneable and pretty efficient. And low cost (you'll spend 2x as much and far more headache with the MSII). I am not dissing the MSII, it is a slick system, great that it is a homebrew, Bowling and Grippo (I think that is who did it) did a great job. The MSII does well with GM sensors, even new ones, so I would expect the software is pretty good to work with old ones too. It does real time tuning out of the box, which is something I don't know if you can do on the TPI setup (maybe with TunerProRT)

I myself would take a TPI computer, SD type (you can use MAF if you want, I would just keep it out, simpler and once tuned for the application, the SD ECM does great), and adapt the Cadillac 6L or 7L or 8.2L to it. I think it would make a great combo. I guess for me I have experience in tuning and electronics, so it would be pretty easy to do. I have used the MSII software, and TunerProRT and TunerCat and the MSII is pretty difficult in comparison. The MSII software is open where you can make your own changes and additions if you know how to program. Like the idle control, then write it in. But what is in the MSII now it isn't very good now. Cold idle set, warm is too high, warm set, cold too low. It isn't setup well yet at all. But it will come soon I am sure.

If you do anything with MSII, I will hook you up with my friend, he has some mods that are needed in the MSII PCM, something a friend of mine found that will probably be in the next hardware release.

Are you suggesting a late 80s TPI computer with a early 90s TBI?

TPI, the 6L, 7L and 8.2L fuelie engines are already port injected, so take advantage of it. TBI is a waste of effort IMHO. If you are going in that much, go all the way and do it right. A TPI MAF or SD computer is a great choice. I don't think either is true sequential injection, they are still batch fired, but that isn't too big deal, it hurts emissions some, but honestly, it is still port injected, which is much more efficient than the TBI or carbie is.

Note, the MSII (That is, MegaSquirt II) is fully capable of sequential port injection, so it has that capability out of the box. So you DO get that advantage there. To get a non LT1, Sequential Port EFI on the Small Block, you need to get a Vortec PCM, and they suck (slow, not well supported in tuning). So a LS1 PCM with the L31 code, might work. But you need to ensure there is a crankshaft sensor (I think the early Cad's did have them) have the same 24x resolution that the L31 with the 0411 PCM have. Again, you can work yourself into some expense, but honestly, you can make a world class EFI out of it too.

Honestly, the reason the TPI's DIDN'T have sequential (in my book), is the lack of crankshaft sensor. This would have required some front cover mods that costs more $$. They knew the LT1 was coming and it got it, with the full super high res 720x crankshaft resolution. It was the first true sequential port SBC (and it didn't get the sequential port turned on till 1994). I suspect for memory requirements, but I can't be sure on that. The 92-93 LT1's were socketed PROM based PCM's, the 94-97 LT1's were flash memory, like the rest of all GM V8 PCM's/VCM's that followed.

Ok, why do I keep talking TPI's? They are simple enough ECM's that should power the older Cad V8 with relative ease. I think it would make an economical upgrade on the Cad DEFI to make it worthy and tunable. Likely make it so a 6L Cad can be upgraded with some good hipo parts and have some real power fun... And get good mpg too.....

Were all of the 6L Cadillac power plants with the 4/6/8 cylinder shut off port fuel injected?

If so could I scavange the computer, intake ...... and so on to make the 425 fuel injected?

If I did this would the fuel data center read out in the car still work?

Could I get the fuel data center to work if I used a carb?

I have access to a complete car with the 6L engine, could I make a hybrid system from that and the 425 and have it run in my 82?

Were all of the 6L Cadillac power plants with the 4/6/8 cylinder shut off port fuel injected?


Nope. They were all TBI.

Does anyone have any suggestions about using the computer, TBI, intake, ect from a 6L and placing on a 425?

I was wondering if you could make some suggestions for my Cadillac project. The car is a 1982 Fleetwood Brougham that I want to yank the 4100 and replace it with an engine that will move the car in a respectable way.

I would like to keep the 2004R that is in the car and fuel inject the replacement engine. I have no problem using a carb but I may need fuel injection because I would like to maintain the “fuel data display “ and all of its functions. Would I also need a computer to control the lockup of the transmission?

I have access to 2 complete donor cars, a 78 coupe with a 425 and a 400 transmission as well as a 1980 Fleetwood with a 368.

Can I make what I am looking for from these cars or do I need something else. The 82 Fleetwood would be a daily driver so fuel economy and reliability are a must. What would you suggest?

My bad, I thought all the Cad V8's were port FI until the 4100 which was TBI...

Sorry! Well, time to get a 425/500 PFI intake! Or get good at welding in injector ports...