Hello, my name is Mat. My very first car was a 1985 Fiero GT v6 4 speed. loved that car and planning to get another.
how here is the questions I have. I plan on turbocharging my motor. I have pretty extensive knowledge with turboing, tuning, everything. I have tuned for E85, gasoline, timing, everything so that wont be an issue. I am planning on using an AEM ECU + 60lb injectors, a BorgWarner S259SX bullseye turbo, along with a bunch of other parts from one of my other builds. I will be making the manifolds myself, twin Tial external wastegates. all the goodies.
Now what I am wondering is, with a spot on tune, and relatively high boost, how much can a 2.8 in stock form handle? I know the compression ratio is under 9:1.
What I'm wondering is, around what power level ( remember spot on tune ) does the pistons melt, rods break, crank snap... that type of stuff. Where does it fail from power, NOT detonation?
I read quite a bit on this forum already, and for anyone who wants to post " please don't use that POS 2.8L " " swap it with a xxxx or xxx" please I don't need your input. ( not trying to sound like a jackass). I just love building underdog engines and making them see power levels other think was impossible. I understand a 3800SC is a better engine, or a 3.4 dohc, or even a 3.1 for that matter. that I do not care, I want to see just how much abuse a 2.8 can take.
I don't have a fiero yet, but I will be picking one up and have lots of plans for it.
The stock 2.8 really wont hold alot of boost. Esp without a full rebuild. Hell my second one was a 2 owner car had 65k on it and the lower end just literally rattled apart.. there is extensive work needed ro get the power your looking to accomplish. Take it from someone whose built quite a few of these engines. If you dont have a fiero yet to do any of this to. Keep an eye on craigslist and the mall here theres plenty of uncompleted swapped cars for decently cheap. I am in no way steering you against doing what you want. Im just giving you honest facts I hope this helps a bit.
My 87 GT has 145,000 miles on it, but I haven't beat on it in the 28 years I have owned it. I had a friend who had 300,000 on his 86 SE, also a car not beat on. Boosting it etc. will shorten its life, and if it already has miles on it, I doubt that it can take much abuse at all.. You may get a few runs with it boosted then boom.
Wow.. I'm realy dissapointed that the 2.8 is so gutless. my 2.5L 4 cylinder in my mazda makes more than that to the wheels.
For a v6, and being smaller displacement 2.8 it should be able to pull some good HP up top and at least rev higher..
Even after seeing all of this, I still want to build it up and turbo it. I think some good boost numbers like 15-18psi on my S259sx should net around 35-38lb/min of air, and rev the engine out to about 7-7500. It will be fun! even if it breaks it will be fun, I can get another engine for pennies, and just lower the power to a safer point.
Nobody ever said "Boy, that thing I never tried sure was fun!!"
Which reminds me of the 'Great One'...who said......"You don't score on 100% of the shots you don't take"
A lot of people have played around with the 2.8, and nobody is blown away by the results...but we always try to encourage the next guy....so Go For IT!
The 2.8 has no provisions for a simple 7x crank sensor however you can rig up an external sensor. I would think you would at least want to go DIS rather the 2.8 distributor.
I haven't seen anyone come up with a high def crank sensor. Thus the ECM won't be able to determine misfire.
The 2.8 has no cam sensor so you can't do sequential injection.
The 2.8 has no provisions for a simple 7x crank sensor however you can rig up an external sensor. I would think you would at least want to go DIS rather the 2.8 distributor.
I haven't seen anyone come up with a high def crank sensor. Thus the ECM won't be able to determine misfire.
The 2.8 has no cam sensor so you can't do sequential injection.
none of that should be a problem. as long as I can get a rpm signal and injector pulses from the stock ecu, I can do the rest. I plan to use a AEM FIC fuel ignition controller, just for the ease of it. the stock ecu won't be controlling anything, just giving information to the AEM.
The 2.8 does use 6 individual injectors right? in batch fire mode?
I don't care how crappy the engine is, I'm not willing to give up until I put a hole in the block. Just like my Nissan, everybody said the engine I chose was a boat anchor POS junk. Then I turn around and make 535WHP out of it. ( RB20, 2.0L straight six. yes TWO liter 6 cylinder ) I love the engines everyone hates. and it's not about being arrogant or not taking advice, it's about the challenge.
[This message has been edited by Orangevirus1 (edited 01-09-2014).]
Just like my Nissan, everybody said the engine I chose was a boat anchor POS junk. Then I turn around and make 535WHP out of it. ( RB20, 2.0L straight six. yes TWO liter 6 cylinder ) I love the engines everyone hates. and it's not about being arrogant or not taking advice, it's about the challenge.
Any videos of it? Would be interested to hear what that sounds like at WOT
the 2.8's prior to 1988 don't flow oil as good as the 88+ blocks, however they can be modified to stock rods are rated to 7000 rpm, you can use V8 H rods by narrowing one end of them
La Fiera's 2.8 went on to make 172 rwhp with CNC ported heads which he offers as a service for $400, my only complaint about his porting job is that he removed the vane that guides air around the valve stem to balance the flow around the valve... I had heads hand-ported that left the vane and have made more HP but I was also using a 3.4, not a 2.8 though the heads are the same...
The 2.8 already comes with 8.9:1 compression (if you want to lower the compression to 8.5 just swap out to the 1.6"/1.3" valves...) so punch it until it blows up, then get a 3100 block and you can stick a 2.8 crank and pistons and take advantage of the roller cams that are out there and full roller rockers...better baffled oil pan and higher flow oil pump...if you are dead set on 2.8L... It's just a better block...
[This message has been edited by lou_dias (edited 01-09-2014).]
I love the engines everyone hates. and it's not about being arrogant or not taking advice, it's about the challenge.
you should try getting 200 out of an iron duke
but seriously... I was on the fence about turboing a 2.8 not a bad idea, as long as you keep it under 10psi. after that, you have to deal with the head gaskets blowing. and then the heat if you want more boost.
and if you want to make the power, you have to reinforce the bottom end, research shows the stock crank is the weakest part in the bottom end as far as making power is concerned, the 60* engines have a naturally bad oiling design, so chamfering the crank and modifying the bearings as well, to help out, is a must.
so far the only off the shelf crank I'm aware of is the eagle crank, its cast steel rated for "400hp" then the rods, sbc rods are recommended as an upgrade, or you can buy some forged ones. they're out there. and then there's obviously the cam profile, there is only so much lift and duration you can get out of a cam before you have to modify the heads for heavier springs.
you definitely overcome the intake restriction problem the 2.8 has, with a turbo, and I don't see 10lbs being too bad, that should be about 280 crank hp.
there are a few articles on here, where you'll read up on what was working and what wasn't, and after reading that, you should have a better idea about where you'll be. one article has a dyno test at about 375whp and 400ft/lbs
but seriously... I was on the fence about turboing a 2.8 not a bad idea, as long as you keep it under 10psi. after that, you have to deal with the head gaskets blowing. and then the heat if you want more boost.
and if you want to make the power, you have to reinforce the bottom end, research shows the stock crank is the weakest part in the bottom end as far as making power is concerned, the 60* engines have a naturally bad oiling design, so chamfering the crank and modifying the bearings as well, to help out, is a must.
so far the only off the shelf crank I'm aware of is the eagle crank, its cast steel rated for "400hp" then the rods, sbc rods are recommended as an upgrade, or you can buy some forged ones. they're out there. and then there's obviously the cam profile, there is only so much lift and duration you can get out of a cam before you have to modify the heads for heavier springs.
you definitely overcome the intake restriction problem the 2.8 has, with a turbo, and I don't see 10lbs being too bad, that should be about 280 crank hp.
there are a few articles on here, where you'll read up on what was working and what wasn't, and after reading that, you should have a better idea about where you'll be. one article has a dyno test at about 375whp and 400ft/lbs
Nope, won't touch an iron Duke. When I was working with the guys in the huge Fiero yard and Shop in Las Vegas I saw an iron Duke.. the crank doesn't even have counterweights. whoever designed that................................... Btw that Shop in Las vegas is where I got my first fiero! First car. loved it, those guys were awesome and helped me, too bad my parents made me get rid of it.
I bet I could get 200 out of an iron duke for 1 single pull before the crank snaps in half.
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Originally posted by lou_dias:
the 2.8's prior to 1988 don't flow oil as good as the 88+ blocks, however they can be modified to stock rods are rated to 7000 rpm, you can use V8 H rods by narrowing one end of them
La Fiera's 2.8 went on to make 172 rwhp with CNC ported heads which he offers as a service for $400, my only complaint about his porting job is that he removed the vane that guides air around the valve stem to balance the flow around the valve... I had heads hand-ported that left the vane and have made more HP but I was also using a 3.4, not a 2.8 though the heads are the same...
The 2.8 already comes with 8.9:1 compression (if you want to lower the compression to 8.5 just swap out to the 1.6"/1.3" valves...) so punch it until it blows up, then get a 3100 block and you can stick a 2.8 crank and pistons and take advantage of the roller cams that are out there and full roller rockers...better baffled oil pan and higher flow oil pump...if you are dead set on 2.8L... It's just a better block...
Stock compression will be just fine for boost. I've tuned cars for boost with compression ratios from 7:1 to 12.4:1 with boost. 8.9 should be no problem holding down some real pressure without detonation. When you say narrowing,does that have to do anything with changing the big end bores or wrist pin bores?.
The thing that I've learned along the way is that boost pressure ( for instance 10psi ) isn't really relevant to power. Since 10psi on my Borgwarner S259SX may put you at about 300+whp, and 10psi on a K03 may make 160whp. I could take a KKK K04 and push 22 psi and make that same amount of power with less than half that boost on a larger turbo.
About how much HP do I need to get into the 12's?
Also 4speed manual or 5 speed?
Finally, I've always wondered this, what does the 4 speed manual top out at in speed?
[This message has been edited by Orangevirus1 (edited 01-10-2014).]
There's a bunch of turbo 3.4 DOHC's over 400 whp, I saw a Fiero dyno a while back of around 490. Their strengths are flow and RPM, weaknesses are the oiling system and timing belt.
Originally posted by Orangevirus1: For a v6, and being smaller displacement 2.8 it should be able to pull some good HP up top and at least rev higher..
Even after seeing all of this, I still want to build it up and turbo it. I think some good boost numbers like 15-18psi on my S259sx should net around 35-38lb/min of air, and rev the engine out to about 7-7500. It will be fun! even if it breaks it will be fun, I can get another engine for pennies, and just lower the power to a safer point.
7500 is an unreasonable rpm target without a lot of work. The intakes and heads are restrictive on these motors, even though the turbo will help counteract that, 7000 would still be difficult to make decent power at.
If you picked up a 3100 block, you'd end up with a better oiling system, and if you upgraded to the 3100/3400 heads you would also have better heads and intakes. A cam-only 3400 can make power to 7000 with proper valve springs. The aluminum heads are nice for boost as well; people have run high compression + turbo motors with the aluminum heads on pump gas without knock retard problems. You could still run a 2.8 crank if you wanted to and to achieve the same 8.9:1 CR IIRC you could use gen II 2.8 pistons.
La Fiera's CNC ported heads flowed 185 cfm, or the same as the GEN3 aluminum heads stock. Heads are not the issue. Do the DAWG intake neck mod and port the intake opening to 57 mm and get the throttle body ported to 57mm.
I've put down 187rwhp(249 ft*lbs) thru a ported fiero intake and heads (before the DAWG mod) on a Mustang dyno at 4100 rpm with a 3.4...no reason why a 2.8 couldn't do that at a higher rpm and that was naturally aspirated with 9.9:1 compression.
Once you hit 160 rwhp, adding 7psi of boost (240hp) should put you at 13.0 so as you can see, it is attainable.
I have done a bunch of research on the forum and rest of the internet in regards to turboing the 2.8... I have since chosen to go with a different engine but that is because I want to beat the crap out of it... anyways the only failures I have come across were ring landings breaking (not from detonation), not to say there aren't others, but I think the stock pistons are the first limitation.
I built a 2.8 from all brand new parts, made sure everything was absolutely perfect, but man it is so hard to get that engine not to leak something somewhere. All the gaskets on the entire engine suck besides the valve cover gaskets which are molded silicon. Seriously every gasket just sucks and all the mating surfaces are simply flat and do not promote keeping the gaskets in place very well.
At around 3000 miles on my build, the heads settled and pulled away from the LIM. The gaskets under the LIM allowed oil to be pulled into the intake upon deceleration, and the crappy rtv bead you need to make yourself between the LIM and block started letting a lot of oil spill all over the block. So I took the top end apart and replaced the gaskets and cut grooves into the block and LIM for the RTV bead so it stays in place. Now my oil pan gasket is leaking right under the flywheel where the pan meets the block.... and it has only been a few thousand more miles...
I was meticulous with this build, I made sure everything was perfect because I have rebuilt a 2.8 before and they are notoriously leaky. I'm only bringing this up because it seems that's how this whole engine is, not very well thought out, and while it might hold the power, it will definitely find a way to create more problems. I would just take this into consideration when it comes to the long term.
There is one 2.8 turbo making ~400HP but that engine is very custom, pretty much just the block is stock, but even it has been modified.
The weakest link on the 2.8 V6 is the bottom end... specifically bottom end oiling. The Chevy Power Manual from the '80s describes a method for modifying the crankshaft to improve oiling. I would also suggest using a hi-perf oil pump.
Okay thanks for all the replies so far. Have a few more questions
when it comes to the oiling on the 2.8, is it that the stock oil pump doesn't make enough pressure? or are the bearing clearances too tight? to loose?
How much power can the stock clutch hold?
Lets say I was to do a swap in the event I blow up a 2.8. What is the hands down easiest 1:1 swap that wouldn't require custom mounts, would bolt straight to the bell housing, etc.
Does anyone know what the 4 speed manual tops out in MPH?
MY8 = 3.32 final drive (1984 model year only) First was slightly shorter (3.53 vs 3.31) and fouth was slightly longer (.73 vs .81)... M19 = 4.10 final drive (1984 model year only) Same gear ratios as the 3.65 M17
[This message has been edited by carbon (edited 01-10-2014).]
Okay thanks for all the replies so far. Have a few more questions
when it comes to the oiling on the 2.8, is it that the stock oil pump doesn't make enough pressure? or are the bearing clearances too tight? to loose?
Nope the design just wasn't very refined in it's first iteration and the crank journals run short on oil at prolonged high RPM operation. Starting on page 3-6(7) of this PDF shows the oiling modifications.
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How much power can the stock clutch hold?
WAG? Probably more than 200, less than 250... basically anything stock and naturally aspirated from GM with six cylinders or less...
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Lets say I was to do a swap in the event I blow up a 2.8. What is the hands down easiest 1:1 swap that wouldn't require custom mounts, would bolt straight to the bell housing, etc.
93-95 Camaro/Firebird 3.4L
[This message has been edited by carbon (edited 01-10-2014).]
3.4 from a camaro or firebird. But you will need a starter jig.. you can easily run a 3400 sif aswell... all you need to modify is the alternator location and wiring beings you are using your own pcm setup a 3400 can do some major power. All I did with a 3400 timing setup was removed the a/c pump . removed the power steering pump. Put an idle pully in and used a 3100 grand am a/c bracket for a 90-94 gm 3.3L alternator. . You run a 3500 lightweight crank pulley . And an aluminum flywheel get some quick revs. And lovesss some boost.
The 3.4RWD is pretty much exactly the same as a 2.8 but with a bigger bore and longer stroke. 3100s and 3400s are a pretty easy swap and will bolt to a lightly modified 84-87 front mount. You need to make a dog-bone mount for those engines or modify the stock one.
3x00s love boost and with head studs and GM graphite head gaskets will take 14 psi all day long with the stock 9.5:1 CR on pump gas. 9 psi is VERY safe with the stock head bolts. They'll also readily rev to 7000 rpm with a turbo cam.
I'm running 14psi on a 3500 (9.8:1 CR) without any knock retard or bottom end issues with a BW 84-75 turbo. I wouldn't recommend going over 16 psi though with the stock rods.
3.4-3x00 will use an 88 Fiero flywheel ($40ish on rock auto last I checked) and the stock 2.8 clutch/pressure plate.
Oh and before I forget, if you plan on making 300 hp you NEED beefier engine mounts. You'll shred the stock ones in no time. The stock stamped steel trans mount brackets are pretty weak and the bushings are no better. Front mount should be fine as long as you have the twisting motion under control.
I ran a turbo for over 20 years with no issues and had it putting out close on 300 BHP out of a 3.2 (.040" over 3.1 stroked crank build on a 2.8 block). Here is some advice.
You can use the stock crank and rods, they are adequately strong.
You need forged pistons - I went for 8.5 compression and used Ross Racing flat tops.
You need to pay a lot of attention to flow in the ports and intake manifolds, as well as eliminating the usual exhaust bottlenecks
You need to incorporate knock sensing control of the ignition curve
You absolutely need to somehow install an intercooler if you want to run more than about 12 psi boost.
You need to obtain a custom turbo friendly cam (I had Comp Cams make one up for me).
You should spend time and money on making things stronger - I used high lift roller rockers etc.
You will need a better than stock clutch (I used Centerforce)
I doubt that you need 60 lb injectors.
Good luck (I sold my car and the engine is still out there running happily)
Okay thanks for all the replies so far. Have a few more questions
when it comes to the oiling on the 2.8, is it that the stock oil pump doesn't make enough pressure? or are the bearing clearances too tight? to loose?
There is nothing wrong with the OE oil pump. Most common problem is gumming up the intake screen, or too heavy oil.
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How much power can the stock clutch hold?
I have mixed reviews. in my case with a 200 hp v8, the stock clutch is a non-starter but the occasional guy has good luck with them. If you want certain grip you need a Spec II+ at least. That is rated at 417 ftlbs.
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Lets say I was to do a swap in the event I blow up a 2.8. What is the hands down easiest 1:1 swap that wouldn't require custom mounts, would bolt straight to the bell housing, etc.
That is the ironhead 3.4 from a 93-95 Camaro
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Does anyone know what the 4 speed manual tops out in MPH?
My experience with the 3.65 is around 97 mph but then again, I really haven't wrung one out on a long stretch
If you are planning a turbo application on the iron head 60*v6, just don't do it on a tired engine.
Don't use cork gaskets when you do the rebuild. Use copper on the head gasket, rubber on the oil pan.
The SBC conrods are a good idea. I know a guy who built a 300 hp v6 but it was heavily modified. Realistically you can make it do 200 fairly safely
If you want cheaper, the 4.9 is the cheaper route at 200 hp 275 ftlbs in stock form. I did the carb which is more, but I won't have dyno numbers until the spring.
The 4.9 responds well to a turbo. Look up HER86GT an Rockcrawl
Arn
[This message has been edited by Arns85GT (edited 01-14-2014).]
When my friend was drag racing my Fiero he hit 102 MPH with the 4-speed but also hit speed limiter which I forgot to remove in the chip. Speedo would have been pegged by then (140km/h one). It should go faster than that but to know for sure put the gear ratios/tire size in a gear ratio calculator to find out.
