I've been in the process of restoring my recently obtained 87 gt 5 spd manual. Soon after purchasing the car, I noticed that the cradle on the driver's side (near the bushings) is so rotted that the subframe looks like it could fall out any minute on the road. Luckily I got a reasonable frame with minimal rot. So I decided since I am going to have to replace the cradle anyways and the engine will have to come with it I should probably consider the option of engine swapping. The original 2.8 has 200k+ on it but still runs relatively strong however I know it comes with its demons and lack of power. I heavily considered building up the 2.8 to change things up from the norm, but it is just too costly with minimal gains compared to the 3800. So with the backstory out of the way, I've been doing as much research with the infinite sea of knowledge everyone here on this forum has and I still have a few lingering questions that will impact my decisions regarding what series/tranny and some supercharger questions.

1. Firstly, I want to keep the car manual. I understand the stock getrag can only withstand upwards of 250 hp with a rebuild. Plus my original has over 200k on it and don't fully feel comfortable pairing it with a more powerful block. I would like the car to be within 300-350 hp with room for growth up to 400. Any recommendations for a manual tranny that won't be a headache job to fab to pair with the 3800?

2. Secondly, I am currently stuck between series 2 vs series 3. I understand that series 2 is a better fit overall speaking. However, I noticed that series 3 came with a higher flow super (gen V) and more base horse out of the factory. I know that the Electronic throttle is a large issue when it comes to headaches with the series 3 swaps. I was wondering if the Gen V super on a series 3 could be moved over to a series 2. Whichever of the two I decide on will be fully rebuilt anyway. So ultimately since I am going to rebuild the block I am swapping with (either series 2 or 3) would it be more beneficial to choose one over the other?

3. Lastly, (this is what my thought process is at the moment) in a perfect world due to the fitment of the series 2 in the Fieros, if I were to rebuild a series 2 fit it (if possible) with the gen V super that came on the series 3 would I be losing anything that could support the build necessarily by choosing to build the series 2 up over the series 3? I'm mainly just wondering if one series would be more limited than the other in terms of rebuilding/support for more power.

Any insight or tips would be greatly appreciated!
Sorry if it was hard to read lol.

Thanks,
Jackson (AKA MrSins)

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Jackson Blair

first thing you need to do is figure out how bad the rust is, if the cradle is that bad, it's likely not the only rust.

The getrag is totally fine with a 3800, clean it up, put a good clutch in it, and roll.

DBW throttles aren't hard, there's a two basic ways to set it up,


attach your stock throttle cable to a accelerator pedal position(APP) sensor mounted in the engine bay

or

mount an APP in place of the stock pedal and run 6 wires.

That said, last time I drove a DBW 3800, I wasn't impressed with the throttle response, I suspect the throttle calibration was poorly setup from the factory.

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"I am not what you so glibly call to be a civilized man. I have broken with society for reasons which I alone am able to appreciate. I am therefore not subject to it's stupid laws, and I ask you to never allude to them in my presence again."

I invited Lou Dias to trash me in my own thread, he refused. sorry. if he trashes your thread going after me. I tried.

Thanks for the tips eric, so far everything I've inspected on the frame is solid besides one spot that (a welder I know) said he could clean up and patch for me. So I'm fairly comfortable with the everything besides the current cradle. As for the Getrag, would it be able to handle the amount of power I want to put in the block towards it (anywhere from 300-400) or will I have to look into the F23 or other alternatives?

The Getrag might last with 400 hp. Since you have it, I'd vote to keep it. You could send the gears for cryo treatment for some extra strength. Or just drive it and mess with an F23 upgrade if it breaks.

You can definitely put the Gen V supercharger on a series 2. It only requires some minor work. I think either option (series 2 or series 3) should be fine. Maybe search for both and jump on a good deal?

Be careful with rebuilding 3800s. I've heard that the lower end (crank bearings, etc) are tricky. Many examples of rebuilt engines failing. I've seen more recommendations to just leave the lower end alone. Check the compression but otherwise don't change the pistons or lower end.

Find the lowest mile series 3 and control it as a series 2 by swapping on a Northstar throttle body and an LQ4 MAF.

I can build the harness and arrange PCM programming.

UPDATE

After calling close to 20 yards I finally found a series 3 3800sc with 127K I am currently looking into cryo for my gears on the getrag. As for a harness and controlling it as a series II I would love for some more incite before I start to build up the top end of the block. Ole I would definitely be interested to see how you go about your harness and pcm modifications.

3800 Series 2 and 3800 Series 3 supercharged engines are essentially the same except for the blower differences (intake manifolds are different to accommodate the different blower designs) as well as different throttle control systems. You could actually put a Series 3's blower and lower intake onto a Series 2 SC engine and end up with the added power benefit the Series 3 engine enjoyed (which was the result of its newer generation blower).

I would highly recommend ditching the DBW TB and PCM that comes stock on a Series 3 engine if that's what you end up finding. These "early" DBW systems aren't that great and tend to have issues in swap applications, especially when manual transmissions are used. You can use a Series 2 PCM and cable-op throttle body (w/ adapter plate) on a Series 3 blower/engine and it will work fine. If you are going to go this route, it would be best to use a Series 2 harness since it is already set up for a cable-op throttle body and PCM. The injectors on Series 2 Supercharged injectors have EV1 (Bosch) style electrical plugs (like stock Fiero 2.8) while Series 3 SC injectors have EV6 style electrical plugs. Several vendors sell adapters if you don't want to swap out the plugs on a Series 2 harness if you are going to use it with Series 3 injectors.

If you are going to modify your own harness, it would be best to get one from a 1998-05 3800 Series 2 Supercharged W-body car. This would include 1998-05 Regal GS, 1998-03 Grand Prix GTP, 2003-05 Impala SS / Monte Carlo SS vehicles. Non-supercharged harnesses can be used from these W-body vehicles as well but they come with a different style MAP sensor connector (which would actually plug right into your Series 3's 2-bar MAP sensor) but may also have different injector plugs. Some non-supercharged 3800 Series 2 engines had injectors that used Multec2 type plugs (but you can get adapters for these as well). The main reason why you want to start with a W-body harness to modify for use in a Fiero is because it doesn't have an extra fire-wall pass-thru connector like those used in C/H/G body cars (Bonneville, Olds 88, Riviera, etc).

I custom tune PCMs for these swaps so feel free to contact me if you need help with that.

-ryan

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