I've recently completed the supercharger installation on my 3.4L-swapped 1991 Firebird! The idea of plumbing up a turbo, fabricating exhaust manifolds, etc. was all a bit beyond my skill level, but after reading the tales of turbo V6's from the likes of FastEddi, the siren-song of boost proved to much for me. Aside from fabricating the bracket, this is a fairly easy upgrade if you've already removed your smog pump. My engine had already received the typical cam/lifters/porting treatment when I did the 3.4L swap boogie last year, so it was ripe for boost.
The bracket is made out of steel and welded together. I might've been able to save some weight by building it out of aluminum, but since I know nothing about material strength I wanted to do everything possible to ensure this bracket would not break. The "foot" has two bolt holes that attach to the block where the smog pump bolted on.


Mounting holes in block



The unpainted bracket

I used a Vortech V3 SI trim I found on Facebook Marketplace that came off of a 90's Mustang. I had to replace the input shaft seal, but other than that it was in excellent condition. I specifically wanted the V3 so I could avoid running oil lines (the V3 is internally lubricated). Not having any experience with choosing a pulley and knowing this supercharger was intended for a V8, I ordered a 5.0" pulley from Vortech. The supercharger included the bypass valve and a few miscellaneous pieces of tubing off the Mustang as well, some of which I was able to reuse.
I plumbed it up using 3" flexible silicone intake hose and a step-down coupler to adapt it to the 3.5" intake on the supercharger. The 3" tubing just barely fit between the radiator and the A/C lines to end up on the passengers side where the charcoal canister used to be.


Intake hose routing

Hose runs to a small K&N air filter

I'll eventually shorten the hose and build something to hold the air filter, but it works for now.

The output of the supercharger goes to a T coupler with a 1" bung on the side. I added a 12" extension cable to my IAT sensor (Michigan Motorsports makes extensions in various lengths) and screwed it into a 1" puck of aluminum bar stock that had the center drilled out and tapped. This was inserted into the 1" bung on the T coupler. The other end of the T connects to a piece of the Mustang's piping which had the output for the bypass valve. I tee-ed off the vacuum lines on the back of the intake plenum and ran a line over to the bypass valve.


IAT sensor

The serpentine belt routing had to be changed as well. It now runs from the power steering pump, straight to the crank, then to the water pump, then around the supercharger, then up to the alternator. There's not much belt contacting the power steering pump, but I haven't had any issues so far. Other than a few odds and ends like a 2-bar map sensor, that's pretty much all it took. I already had an EBL-P4 installed and was reasonably familiar with tuning it from when I did the 3.4L swap, so after about 3 hours of VE Learns and table editing I had fueling almost perfect. Still room for improvement in timing though; it's set very conservatively right now.


Finished install

I've only driven it during tuning so far, but the 5" pulley makes a maximum of 1.6 PSI of boost at redline. I'll definitely need to get a smaller one in the future and if anyone has any info about how to calculate pulley vs boost I'd be appreciative. This car sees some road trips, so I'd like the max boost to be around 6 PSI. I'm hoping this level of boost will also let me get away with not using an intercooler.

The difference it's made to the low and mid range is already dramatic. The car used to run out of steam as soon as it hit 2nd gear, but now it pulls much more linearly all the way to redline. I would like to eventually get the car dyno'ed, but that's a ways off still...

 

That's cool, tucks in there like it was made for it.

 

Looks good I cant wait to see it with a new intake setup. What are your plans for the rest of the motor? Any porting of the manifold or just some boost?

I am familiar with 3.4 supercharged setups but my best guess is 3.6" will give about 7.5psi but I could be way off
You can try to estimate with this impeller speed calculator
https://vortechsuperchargers.com/pag...eed-calculator

 

I saw that calculator, but I'm not sure how to convert impeller speed into boost PSI. I have a spare 3.6" pulley that came with the supercharger so I'll probably put it on and see what happens. At the very least, it'll give me two reference points when selecting the correct size.
The motor was rebuilt and over-bored and I added a Melling MTC-5 cam, as well as did some DIY porting on the heads. The intake will probably stay stock for the time being due to the budget being stretched thin, but I would like to experiment with a custom 3D printed intake manifold in the future...

The engine work his has only been a small part of this car project. The car has also had ceramic tinting, new carpet, lloyd mats, a full A/C rebuild with a Sanden compressor, front brake pads & rotors, front struts, new tires, new weather stripping, all 4 speakers replaced, new Alcantara head liner, and too many other odds and ends to even list. It's been in the works for about 2 years now.

 

Finally fabricated my air box over the weekend. I used some black coated diamond plating, bent it into shape, and bolted into several empty holes in the body that were there from the factory. I'm pretty happy with how it turned out. It also lowered my intake air temps by 15-20 degrees.

 

What size injectors are you using? lbs/hr? I have a Paxton boosted 91 3.1 and when it ran, they guy who did the tune (and it was an Accel DFI conversion done back in 91) stated the 19/lbs hr injectors were static at around 2/3 throttle and there was a 2-3 PSI differential between the blower and the plenum side of the throttle body. I had that enlarged later and don't ask me what shop did it, as this was back in 91. I am now resurrecting this project.
Thanks in advance.