Hello everyone. I am a proud owner of a 1988 Fiero GT. I want a little more umph from the car so I would like to turbo it. I would not like to swap for a 3800 which I know some people wouldn't like but I feel like it's over done and this is my first car and I want to jump in to know how to turbo it. I've read a bunch on the forum about how you shouldn't go over 6-8 psi of boost on the stock 2.8 and how it would be cheaper to fabricate your own system then buy a premade one. I will only be taking the engine to around 200 for now as an fyi. But I haven't heard much about what supporting mods you should get to ensure the engine can keep up with the boost. So if anyone knows what I should upgrade before boosting, fuel pump, spark plugs, injectors, turbo fuel pump, ECU, intercooler, transmission(I believe mine is from an automatic from 1987 or 1986), or anything else. Please let me know. And last thing what size turbo should I get? I'm not looking to go very fast merely have fast acceleration to have a fun car so something to reduce the lag more than anything but not completely lopsided towards acceleration though? I have big plans for this car and cannot wait to get started!
Most will tell you not to boost the 2.8. However, if you keep it low, I am sure it will be fine. If I were to take this route, I would build a 3.4L block for boost. That way it will look completely stock. There is not going to be too much support for 2.8 boost. You will need to source most of your own stuff. The money spent for this might push you over just putting a 3.8 motor in. Keep that in mind.
My first project many moons ago was a DIY turbo for my 2.8L Fiero. The car was fast and ran well. It can work for you if you follow the following rules. 1. The engine must be in top condition. Under 50K miles would be best 2. You must fabricate the oil feed and return line. I welded a bung on the oil pan for the return and took the oil supply from a three way fitting off the oil pressure sender 3, More fuel and less timing under boost is necessary. You could handle the timing retard from an MSD ignition box but the chip must be programmed for more fuel under boost. I used a 2 BAR map sensor and a split timing table with two halfs with vacuum and boost level timing parameters, More fuel was added from altering the fuel table values in the chip. To do this you must have extra 2732 blank chips, the eprom editing program for the chip, a programmer and an eraser. If you are still with me then be prepared to fabricate a crossover pipe to mount the turbo and plumb it to your exhaust system. I purchased a turbo flange and welded it to a customer pipe. 4 Make sure that you choose a suitable size T-3 turbo that will spool up quickly. Make sure that it is mounted as to not interfere with the deck lid closing.
The easier way is to go electric turbo but suitable size units require 48V power. That requires 4 batteries a larger alternator and switches. You might want to take a look at some of the YouTube videos on how these turbos are installed Not cheap but perhaps easier. For power on demand a Nitrous setup with a SMALL 50 HP shot may keep you happy,
------------------ " THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite. "THE COLUSSUS" 87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H " ON THE LOOSE WITHOUT THE JUICE "
Regarding pre-made kits, there are used turbo kits floating around.
Personally, I find that purchasing things pre-built usually ends up cheaper than making things on my own. With DIY, there is often a bunch of time and money wasted on scrap and failed attempts before finding the correct solution.
Minimum suggested supporting mods/maintenance on the engine would be cam bearing replacement (needed to ensure adequate oil supply to all the engine), timing chain replacement (wears quickly), and ring gap inspection/increase (turbo engine uses greater ring gaps than NA).
A genuine ACDelco EP381 fuel pump is common, in conjunction with the Darth Fiero hot-wire mod.
Fuel injectors are up to you. They can be replaced easily, so it is not a big deal if you run out of capacity and need to install higher-flowing ones.
Stock ACDelco R42TS spark plugs are fine. You may need to reduce the spark plug gaps to ensure reliable firing at higher boost levels.
I don’t think that an intercooler is desirable for 6-8 psi. You can search the forum to find typical intercooler installation solutions.
You need a way to tune the engine computer to work with your mods. Either use a stock computer, or something else which may be more easily tuned.
I can’t comment on the automatic transmissions, I don’t know much about them.
Turbo sizing is up to you, depends on what kind of powerband you want. It may be more challenging to have a reliable project where the boost comes in down low. At low RPM, knock is more likely. At low RPM, the engine’s bearings have less capacity. The “modern style” of turbocharging uses a small turbo that spools up quickly, but doesn’t breathe up top.
Must caution you that the Fiero 2.8L engines use cast pistons that are not very forgiving on anything less than a perfect install on a fresh engine. I would not go above 6-7 psi of boost on a 30+ yr old engine. I used custom Ross forged pistons on my 3.4L build. Not sure where you can get forged pistons for the 2.8L
------------------ " THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite. "THE COLUSSUS" 87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H " ON THE LOOSE WITHOUT THE JUICE "
I don’t think that you need the strength of a forged piston for a low/moderate power project. Lots of factory turbo cars have cast pistons.
My iron-head V6 has been running 15 psi on cast pistons
When you turbo a mostly stock iron-head V6, you’re basically making the power of a newer NA V6, which would not need strong pistons for that power level.
Are connecting rod bearings not the weak point of the Fiero V6, rather than its pistons?
I don’t think that you need the strength of a forged piston for a low/moderate power project. Lots of factory turbo cars have cast pistons.
My iron-head V6 has been running 15 psi on cast pistons
When you turbo a mostly stock iron-head V6, you’re basically making the power of a newer NA V6, which would not need strong pistons for that power level.
Are connecting rod bearings not the weak point of the Fiero V6, rather than its pistons?
the connecting rods and rings seem to be the weakest bits. seen alot of 2.8s with wrecked blocks from a rod going
I had a turbo 2.8 V6 engine with a Getrag 282 in one of my Meras and it completely died due to engine problems at around 60k miles. No race type driving but a couple of spirited romps were seen. The boost level was around 6-7 psi with no intercooler. The best thing that I ever did was to pull the turbo components and sell them to fund a portion of a 3800 SC swap.
Note that I still have a turbo 3.4 setup on one of my cars, but that was using new/less than 8000 mile components designed for the application. There are custom fuel tables required and a few other issues. That car cost me more than a 3800 SC engine swap but I did a few other things that make it "cool" to look at during car shows.
I had a turbo 2.8 V6 engine with a Getrag 282 in one of my Meras and it completely died due to engine problems at around 60k miles. No race type driving but a couple of spirited romps were seen. The boost level was around 6-7 psi with no intercooler. The best thing that I ever did was to pull the turbo components and sell them to fund a portion of a 3800 SC swap.
Note that I still have a turbo 3.4 setup on one of my cars, but that was using new/less than 8000 mile components designed for the application. There are custom fuel tables required and a few other issues. That car cost me more than a 3800 SC engine swap but I did a few other things that make it "cool" to look at during car shows.
Nelson
X2 My turbo 3.4L has Ross forged pistons, Total seal rings, a Comp Cam and all new bearings; that build cost way more than my 3800SC swap but after tuning I spent another $800 on the 3800 intercooler setup. With that in mind, I should have started out and stayed with a 3800SC on that build, because it was designed by GM for boost.
------------------ " THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite. "THE COLUSSUS" 87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H " ON THE LOOSE WITHOUT THE JUICE "
[This message has been edited by Dennis LaGrua (edited 10-02-2024).]
I had a turbo 2.8 V6 engine with a Getrag 282 in one of my Meras and it completely died due to engine problems at around 60k miles. No race type driving but a couple of spirited romps were seen. The boost level was around 6-7 psi with no intercooler. The best thing that I ever did was to pull the turbo components and sell them to fund a portion of a 3800 SC swap.
Note that I still have a turbo 3.4 setup on one of my cars, but that was using new/less than 8000 mile components designed for the application. There are custom fuel tables required and a few other issues. That car cost me more than a 3800 SC engine swap but I did a few other things that make it "cool" to look at during car shows.
Nelson
When you say 3.4l build do you just mean replace the block and piston and some few things keeping the headers and stuff or a new engine completely?
When you say 3.4l build do you just mean replace the block and piston and some few things keeping the headers and stuff or a new engine completely?
I used a "new" short block directly from a Pontiac dealership. It had less than 8000 miles on it but the vehicle power plant was replaced by one of the LS models. The block is stock with the normal distributor mount change, a custom crank, new pistons (but do not remember which one I used long ago), new injectors, custom fuel tune, Trueleo header, and a Japanese turbo. I guess that I can claim mostly a new engine.
You can just use the short block (block, crank, rods & pistons), and use the rest from the 2.8L.
Ok seems that 3.4 swapping is the way to go. What if I got a 3.4 and put in new rod bearings, performance cam, pistons, ported aluminum headers, turbo, and other supporting mods could that get to 300hp reliably if you know?
I used a "new" short block directly from a Pontiac dealership. It had less than 8000 miles on it but the vehicle power plant was replaced by one of the LS models. The block is stock with the normal distributor mount change, a custom crank, new pistons (but do not remember which one I used long ago), new injectors, custom fuel tune, Trueleo header, and a Japanese turbo. I guess that I can claim mostly a new engine.
Nelson
Seeing all the other responses it seems like that's the way I'm going to go. Do you know how much HP you could get out of this setup that's reliable?
You are limited by boost if you do not use an intercooler - 10 psi is about all you can use without knock, which can quickly destroy an engine.
I built my turbo engine back before the 3.4s were available so I used Ross pistons and 10 psi boost limit.
My current car (Solstice) run a 2.0 engine putting out 375 bhp at c, 25 psi of boost - how times have changed!
Be sure to get good pistons - I also had Ross make me some and they lasted in the turbo motor for 20 years! I also used a 3,1 crank for the longer stroke and bored the engine to get around 3.2 displacement.