Hey guys it's been a few years since I've last had a fiero,I just picked up an 85 originally a 4cyl 5speed that has a 3.8 from a 91 regal mounted up. I was told it has run in the car, but the wiring needs to be finished. My original plan was as follows 1. Buy an l67 intake+supercharger+injectors 2. Buy an l67 cars harness and pcm as well as an 85 fiero harness 3. Send the harness off and have a plug and play harness made for the car 4. Throw a smaller pulley on there and have around 300bhp I have since found out that the l67 suoercharger wont bolt up to the ln3 from the regal. I'm not really sure what the best course of action is here. Do I continue with the ln3 and modify that? Should I look for a wrecked series 2 3800 car?
I would say do what your wallet can handle! At the very least sit down and think about what you want, supercharged or NA car? I am not sure on which one is stronger but i have seen some pretty impressive numbers from supercharged 3.8's with not internal mods. At the end of the day they are great reliable motors.
[This message has been edited by Spadesluck (edited 04-25-2017).]
The LN3 was a "Pre series 1" 3800. Made about 165 HP.
From Wikipedia... "Introduced in 1988, the 3800 LN3 would later be loosely considered the Pre-Series I, although the older 3.8 SFI (LG3) was still available that year in some models. Designated initially by VIN code C, the multiport fuel injected 3800 LN3 was a major redesign, featuring changes such as a balance shaft, on-center bore spacing, use of a 3x/18x crank-trigger system, and other improvements. This generation continued in use in several GM products into the 1990s. It produced 165 hp (123 kW) and 210 lb·ft (285 N·m).
The LN3 is very closely related to the Series I L27 and Series I L67 Supercharged. In fact, supercharger-related hardware can be fitted to an LN3 without changing the cylinder heads (ECM reprogramming required). The L27 has a two piece, upper plenum intake and lower intake, the LN3 is all one piece." https://en.wikipedia.org/wiki/Buick_V6_engine
Reader's Digest version... You will need the Series 1 hardware to make this work. Nothing "Series 2" will likely be compatible. The wiring harnesses will probably be more similar than you would expect.
[This message has been edited by Raydar (edited 04-25-2017).]
I spent a lot of money to get my current 3800sc up to 330hp-340hp, so just dropping a smaller pulley on probably wouldn't have pushed you into the 300hp range...
I have done a couple 3800na and 3800sc swaps plus one 4.9L. If I could go back and do it again, I would stay with the 3800na. Same amount of work to do the swap as the supercharged, but 205hp was enough for me and it ran 87 octane. I got 25mpg and was always stabbing the accelerator, there was no being gentle with it.
That said, the 3800sc will keep you pushed back in the seat harder and longer while the 4.9L has that sweet, sweet V8 rumble that I like...
So I'm not really concerned with what gas to run, I'm used to putting 93 in my toys. I just have heard the series 1's aren't as good of a starting point as series 2's. From what I've read, I should be able to put a series 1 supercharger on, and do the supporting mods to make decent power, I'm just debating whether to do this with the unknown motor in the car or just start over with a running series 2 3800
I've made quite a bit of progress, and I believe I have the car ready to fire up. I just have a couple of wires left that I don't know what their purpose was, or when they should be connected to. I'm working on attaching pictures, as soon as I figure it out I'll post them in here
Going by your original post, you cannot use the SC, lower intake and injectors on a series 1. You can't even do a "top swap" due to the blocks being different. If you change anything really you'd need to swap the motor.
The motor mounts should line up the same so that's nothing more coming out of pocket. I'm unsure of the trans though. I'm guessing it's a 4t60.
I did some tracing and learned a few things The top picture those wires run into some sort of junction near the battery (c5000 I Believe), and that splits two ways. One set of wires goes into the cabin though the fire wall, I lost it in the center console. The other set of wires runs through the bumper and all of the wires for the rear lights split off from it. So where in the world are those plugs supposed to be connected? The green wire runs to a sensor on top of the engine, I'm guessing coolant temp sensor The beige wire runs into some sensor plugged in near the oil filter, looks possibly like a knock sensor There was also a plug dangling near the oil filter with purple and yellow wires. I don't see anything anywhere near it to plug it into. They branch off the same set of wires as the green wire and the beige wire.
[This message has been edited by jhobbins (edited 12-01-2017).]
I've got another question for you guys. There's an orange wire, a white wire, and a black wire connected to the aldl plug are connected. There's a green wire that has been clipped and is just hanging there, no obvious connection in site. Is this something that is not used with the swap? I can't find that green wire in any schematics I've looked over.
Originally posted by jhobbins: Not sure from your picture where those wires are coming from, but I have a 3800SC swap in a 1986 GT. I didn't do the swap, but have been sorting through some issues (it was an early swap). There were several wires that have a square four way connector that was loose down by the low mount alternator. I checked the wire colors against the factory service manual and also looked for anything similar around the engine. I think that the plug went to an O2 sensor. There were also another set of wires that went to two connectors. These came up through the passenger rear area of the trunk (back side by the bumper). These were for the blower motor and its relay. Just cut them off sealed the ends of the wires that still had current. I've made quite a bit of progress, and I believe I have the car ready to fire up. I just have a couple of wires left that I don't know what their purpose was, or when they should be connected to. I'm working on attaching pictures, as soon as I figure it out I'll post them in here
I'm 99% sure I have everything wired correctly, but when I go to start it i get nothing. I tested the starter and it was dead so I replaced it with a rebuild from the parts store. After hooking this one up I still got nothing. After attempting to jump the connections and apply 12v directly to the signal wire, I could hear the gear jump out but nothing else. After bench testing the starter I saw that the gear was sliding out but not spinning. I took it back to the parts store, and they replaced it for me. I had them test this one to verify the gear came out and spun, which it did. After installing this starter and applying 12v to the signal again the same thing happened. I bench tested it and now the gear will come out but not spinning just as the one before it. Am I some how shorting out the starter? I don't understand how that could make the gear not spin
try cleaning your grounds off. If the gear jumps but doesnt spin, not enuf power is getting to the starter. Loosen n tighten all power connections from battery to solenoid.
