So, sometime down the road (not any time soon), I'm going to do a powertrain swap on my '86. I really kinda like the idea of trying to beef up the stock 2.8, but I'm seeing mixed feelings on that in the forums. Since some of those threads are (really) old, I thought I'd start a new one and ask the question: can you effectively boost the 2.8?
I was thinking if I could push that 2.8 up to around 200-220 hp, the power-to-weight ratio wouldn't be bad at all, and it'd be a pretty quick little machine. My other thoughts are: 1. The 3.8L Supercharged motor 2. LS4 (I have fond memories of this engine from when I had a Grand Prix GXP) 3. 3.4L swap with some performance upgrades 4. EV conversion (which I would build for performance, and thus can't afford until prices come down a bit more on the motors/batteries) :-)
I actually like the boosted 2.8 and EV conversion options best (I know many petrol heads are going to be mad about that). If I go EV, I LOVE the idea of instant torque--I'm kind of addicted to it as my daily driver is a Chevy Bolt. Heck, I'm betting you could modify the section of the car that houses the gas tank to fit the T-cell shaped batter from a Volt!
Anyway, I digress. In the (relatively) shorter term, I want to see if I can boost the performance of the 2.8L that's currently living inside my Fiero. So, what has worked with the best results? Is it just a bad idea to tinker with what seems to be a fairly reliable motor?
I think turbocharging the stock V6 is a good idea; it's the least fabrication-intensive option among those you presented. I don't view a 3.4 bottom end as much of a swap; it is more of a variation on a 2.8.
Like any other powerplant choice, the power you'll get out of is is related to the time/money you put into the project. You'll probably want to tear down the engine for inspection before putting a turbo on it. You can also wait to blow up the original engine, then replace the shortblock at that time.
If you want instant torque, a turbo (with its lag) is not for you. Stick with a blower, naturally aspirated, or electric.
A lot of the turbo threads are old, but the information remains mostly valid, because the 2.8 itself hasn't evolved with the times. I personally have an active V6 turbo project thread; it's presently accessible from the first page in the Tech section.
You can play with the turbo sizing to favour high-end or low-end torque, according to your tastes.
The 3800SC and LS4 already make good power out of the box, but those can be turbocharged as well if you have a large appetite for speed.
My first upgraded engine was a stock 2.8L w a turbo that came off of a Ford 2.5L T bird engine. The electronics were via a reprogrammed chip with a modified timing table ( stock ECM) that took inputs from a new 2 BAR Map sensor. The engine had 60K miles on it. Performance was substantially improved but because of the cast pistons I held the boost to 5-6psi. If I were to guess the engine was probably making 190HP. If you want a bit more power and maybe a 14 second 1/4 mile the turbo will provide it, but you can't go much farther than that. Cast pistons, especially old ones won't survive with higher boost. You might also try a small shot of N2O for more power. There have been guys who added a 50 hp Nitrous shot and have achieved about the same result as by adding boost. Cheap way to do it but in both cases you must use premium gasoline.
------------------ " 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 "
You'll probably want to tear down the engine for inspection before putting a turbo on it. You can also wait to blow up the original engine, then replace the shortblock at that time.
I probably should've elaborated in my previous post... but yeah, I totally agree with what you've stated here. Putting a turbo on a tired old 2.8 is a recipe for disaster.
To elaborate further on the turbo. I would like to agree somewhat with Patrick that blown engines could result. If your 2.8 engine has more than 50,000 miles on it, ( and almost all do) forget about the turbo idea . Less than 50,000 You will probably get away with it if you keep the boost to five to six pounds
Something I should've mentioned was that, regardless of whether or not I add a turbo, I'm going to tear down the engine and refurb it (probably rebuilding bits and pieces, but not necessarily the whole thing). That'll likely include a trip to a machine shop. If I'm going turbo, I'd have them set it up for a turbo, and ask them for advice on amount of boost and what not. I'm definitely not slapping a turbo on there now without any prep :-)
There's something very appealing to me about keeping the original engine and upgrading the thing to get moar power. Kind of completes the car's revival story, ya' know? I also just want more power because, well, this is supposed to be my fun/project car, and it seems like a part of that should be coming up with clever ways of getting more power without destroying the drivetrain.
I'll likely do suspension upgrades well before I do a powertrain swap though . . .
There are a few things that can make a turbocharged 2.8 V6 problematic. For example, it doesn't have a knock sensor. So if it runs lean, or has too much spark advance, you'll probably melt pistons. It also has no provision for electronic ignition. You can run low boost with a distributer, but it will tax the ignition system. Also, the bottom-end oiling in the 2.8 is marginal. The bottom end shares oil flow with the lifters on one side of the engine.
To install a turbo, and do it right, you'll need to address those issues. So in addition to the turbo upgrade, you'll also be retrofitting a knock sensor and electronic ignition, and modifying the crankshaft to improve oiling. Unfortunately, there's nothing you can do about the shared oil flow. That's built into the engine block.
You'll also need a different ECU. But that's true for just about any swap.
In later versions of the 60-degree V6, all those problems are addressed. They have knock sensors, electronic ignition, and better bottom-end oiling. This IMO is the main reason to trade up to a 3.4 V6. It's only a minor power upgrade, but a big durability upgrade. And if you use one of the 3100 / 3400 V6 engines, they also have reinforced main bearing caps, and roller lifters.
So if you're serious about the turbo upgrade, I would suggest getting a short block from a 3.4 or 3400, and build on that. It'll still look like the original engine, to the untrained eye. But it'll be much more durable, with more power potential.
[This message has been edited by Blacktree (edited 08-25-2020).]
2.8 w/119k on it. I did replace the rod/main bearings and oil pump, but it’s pretty much stock bottom otherwise. I mean, the heads haven’t even been off.
It’s a lot of fun!
[This message has been edited by Honest Don (edited 08-25-2020).]
2.8 w/119k on it. I did replace the rod/main bearings and oil pump, but it’s pretty much stock bottom otherwise. I mean, the heads haven’t even been off.
It’s a lot of fun!
Nice engine bay! If you do little short pulls and drive it conservative it'll be a nice show car and give you lots of satisfaction. If you push it and for example take it to a track day weekend I can guarantee you you'll be sharing the front seat with Bubba, the tow truck driver giving you and your car a ride home. I'm telling you from my own experience. My N/A 2.8 had 173WHP @ 6000rpms and with the bad designed oiling system it was just a matter of time before it showed its flaws. Another advantage for using the 3.4 over the 2.8 for turbocharging is the difference in rod ratios.
Nice engine bay! If you do little short pulls and drive it conservative it'll be a nice show car and give you lots of satisfaction. If you push it and for example take it to a track day weekend I can guarantee you you'll be sharing the front seat with Bubba, the tow truck driver giving you and your car a ride home. I'm telling you from my own experience. My N/A 2.8 had 173WHP @ 6000rpms and with the bad designed oiling system it was just a matter of time before it showed its flaws. Another advantage for using the 3.4 over the 2.8 for turbocharging is the difference in rod ratios.
Thanks! I did the turbo back in 08-09. There have been a few hiccups along the way, but mostly nothing catastrophic so far. It's just a beat-around-town car with the occasional visit to the local 1/8th mile.
Power drops off around 5000rpm so I try not to shift too much higher than that. I actually had to get into the governor and move the shift points down a bit. As the boost went up, so did my engine rpm at the shift thanks to convertor slip.
[This message has been edited by Honest Don (edited 08-26-2020).]
There are a few things that can make a turbocharged 2.8 V6 problematic. For example, it doesn't have a knock sensor. So if it runs lean, or has too much spark advance, you'll probably melt pistons. It also has no provision for electronic ignition. You can run low boost with a distributer, but it will tax the ignition system. Also, the bottom-end oiling in the 2.8 is marginal. The bottom end shares oil flow with the lifters on one side of the engine.
To install a turbo, and do it right, you'll need to address those issues. So in addition to the turbo upgrade, you'll also be retrofitting a knock sensor and electronic ignition, and modifying the crankshaft to improve oiling. Unfortunately, there's nothing you can do about the shared oil flow. That's built into the engine block.
You'll also need a different ECU. But that's true for just about any swap.
In later versions of the 60-degree V6, all those problems are addressed. They have knock sensors, electronic ignition, and better bottom-end oiling. This IMO is the main reason to trade up to a 3.4 V6. It's only a minor power upgrade, but a big durability upgrade. And if you use one of the 3100 / 3400 V6 engines, they also have reinforced main bearing caps, and roller lifters.
So if you're serious about the turbo upgrade, I would suggest getting a short block from a 3.4 or 3400, and build on that. It'll still look like the original engine, to the untrained eye. But it'll be much more durable, with more power potential.
The solution for adding a knock sensor is to use the 85 Fiero ECM. Thats the only year that contains the knock sensor interface. You'll need the GM Knock sensor, the ESC module (basically an A to D converter) and wires to connect everything together to feed the ECM input pins. Then you must go to the prom chips program, and check the knock sensor feature flag switch to on. Its not that hard to do. I'll try to post the diagram later tonight.
------------------ " 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 "
Originally posted by Dennis LaGrua: The solution for adding a knock sensor is to use the 85 Fiero ECM.
Yes, I know it has knock sensor input. But the stock Fiero ECM is slow. By the time it reacts to the knock sensor input, the damage is already done. Plus it doesn't have provisions for DIS, or WBO2, or boost control.
Yes, I know it has knock sensor input. But the stock Fiero ECM is slow. By the time it reacts to the knock sensor input, the damage is already done. Plus it doesn't have provisions for DIS, or WBO2, or boost control.
If the Fiero ECM isn't fancy enough for your tastes, nothing stops you from using an aftermarket (or other) computer.
The MegaSquirt 3 I have on my Fiero supports all the aforementioned features.
Originally posted by sourmash: No use in keeping the "original" looking engine when the big turbocharger right there screams I'M FAR FROM ORIGINAL.
A turbo obviously doesn't look original to Fiero people, but if I imagine what a top-level turbocharged version of Fiero would look like if GM (or Ferrari) built it in the 80s, I think it's cool to go for that look. Or the look of a 80s tuner who modified the car with the parts available at the time.
So not original, but still retro-style. Turbos were around in the 80s; COP and large plastic engine covers were not.
If you throw away the retro, a part of the Fiero's charm goes away with it. Obviously not everyone thinks this way; there are some who enjoy modernizing their Fieros, and that's fine too.
A turbo obviously doesn't look original to Fiero people, but if I imagine what a top-level turbocharged version of Fiero would look like if GM (or Ferrari) built it in the 80s, I think it's cool to go for that look. Or the look of a 80s tuner who modified the car with the parts available at the time.
So not original, but still retro-style. Turbos were around in the 80s; COP and large plastic engine covers were not.
If you throw away the retro, a part of the Fiero's charm goes away with it. Obviously not everyone thinks this way; there are some who enjoy modernizing their Fieros, and that's fine too.
I daily drove a 1979 turbo Capri RS 2.3L in the early 1980s. I've had several turbo factory cars from 1981 to 1988 and shortened the waste gate rod on them to add some boost. They detonated some. My 1983 I added an intercooler, larger TB and larger exhaust to run about 15psi reliably with an adjustable pop-off valve.
If a person plans to go through the engine then starting with a 3.4 or even going with the 3x00 can be made to look stock. Really it's silly to debate. We aren't going to change minds and it's just daydreaming. Since a turbo Fiero wasn't made what's the purpose of limiting to the stock 2.8 if you're tearing it down? You can have more and it still look the same.
I added a Miller Woods turbo set up to my 88 GT soon after I got it. That gave 190-200 bhp and was a nice result.
While driving it that way I picked up another engine and built it for more pressure - putting a lot of money into parts for reliability as well as increasing flow. It was too soon to be able to find a 3.4 engine used, so I got a 3.1 crank (same as the 3.4) and had pistons made to suit it, as well as punching the block .040" to end up with a 3.2 with c. 300 bhp.
While I agree with the guys that say the stock V6 has some flow issues that are hard to overcome, I preferred to stay with the stock engine, and aside from the usual port flowing, exhaust work and manifold optimization, a turbo is the easy way to drag a recalcitrant engine kicking and screaming, up to a decent output.
I found that the longer stroke was an easily detectable advantage and recommend it. It means new pistons for a 3.1 but the rods aren't changed.
Originally posted by BillS: I found that the longer stroke was an easily detectable advantage and recommend it. It means new pistons for a 3.1 but the rods aren't changed.
Yes. Longer stroke with the same 5.7 rods means rod ratio changed for increased piston speed. More piston speed equals more air drawn in and out faster and that results in more acceleration. Chevy guys use longer rods to get high rpms at the crank while the piston is moving slow, and for short track and acceleration off the corners the long rod motor makes more power but it is a siting duck in a track that has lots of turns or on a short oval track. Longer rods need straights to show their legs while the short rod will out acceleletare the long rod motor off the corners by a long shot. So, in a street motor you want a short (stock) rod if stroking the engine to a 3.2 or 3.4.
