maitlandtron

Hey guys I'm gonna be acquiring an 87 firebird real soon here. I want to keep the engine in it but I know I will get bored and I am looking for something to keep me busy on it. I want to turbo the car with the least amount of money involved. Here are my plans so far.

I'm not worried about the hot side at all. I have the materials and skill to fabricate the manifolds and all of the exhaust.

I want to use an ebay turbo with theses specs.
Compressor:
Trim: 57
Exducer/Inducer: 76.00 / 50.55
A/R: 0.5
Turbine:
T3 Type Turbine Flange
Trim: 58
Exducer/Inducer: 56.6 / 65.2
A/R: 0.63

Internal wastegate.

My plan is to only run 7psi max, can I use 19lb injectors and an boost referenced FPR and call it good?

Will I have any problems with my MAF?

I've read a few V6 threads but these seem to be some unanswered questions.

Any input is appreciated. Thanks.

RubberDucky

iTrader: (4)

The way I understand it is you will need something larger than 19# injectors, but I will let those who have more experience with this chime in on exactly what you need.

maitlandtron

I actually have some stock 22lbs injectors off an LT1, if that's what it will need.

maitlandtron

I had very good luck with my Carb'd SBC turbo build.

project89

iTrader: (1)

skip the 150 $ ebay 57trim , and go right for the 225$ ebay gt3582 , u will be much happier with it trust me

honestly any 2.8/3.2/3.4 i suggest going right to the 42# or larger injectors

if u want to do it as cheap as possible look for an edelbrock 4bbl intake and find a craigslist holley 390 carb and modify it the same way u did the one on the sbc

fasteddi

iTrader: (2)

Agree with project 89.

19lb are way to small. I had 28 lbs when I first did the turbo set up. Doesn't take much power to max them out. Get 36 42 or 48Lbs from south bay injectors. There reasonably priced.

Gt3582 is a great turbo. It's what I run. Good low cost turbo.

Street Lethal

iTrader: (16)

Injector size isn't based on how much boost pressure, rather how much horsepower your literally making; 7-psi on a 2.8 won't yield as much power as say 7-psi on a SBC because base power in stock form, or even bolt on form for that matter, is essentially different to begin with from one engine to another, so you yourself can get away with smaller injectors for your 2.8 at that boost pressure level. However, when I say smaller injectors I mean in the 24-28 lb range, not 19-22lb range. Forget the MAF and go with the SFI-6 from Dynamic EFI, trust me...

caffeine

iTrader: (2)

Bear in mind vs. a V8 the V6 has 2 less injectors so needs bigger injectors/hp.

willexoIX

It also has 2 less cylinders. Though I don't doubt what you say is right, as I don't know everything, but that statement doesn't seem right to me.

Example,

V6 pushing 400hp = 40lb injectors
V8 pushing 400hp = 40lb injectors

I know lb/hr doesn't directly correspond to hp, but is close enough to make the point.

If what you said was true, there would be v8 injectors and v6 injectors. Instead of the same injectors for I4, v6, v8, v10, etc etc...

caffeine

iTrader: (2)

You need fuel to make hp. MPFI V8s have 8 injectors, so 8x40 lb injectors is 320 lb/hr of fuel capability. MPFI V6s have 6 injectors, so 6x40 lb injectors is 240 lb/hr of fuel capability. Therefore if you're close to maxing 40 lb injectors on a 400 hp V8 (and don't have a horribly inefficient engine), you'll need larger than 40 lb injectors to make the same hp with a V6 (two less injectors, but still same/similar fuel requirement means larger injectors are necessary to meet the demand).

There's no such thing as V8 or V6 injectors because for more fuel you just get bigger injectors. I don't know how that doesn't make sense.

maitlandtron

I know that injector size isn't based on boost pressure, but boost pressure determines HP. I was merely looking for someone who has done one one these in stock form and what the minimum requirements for running low boost. To be honest I might scrap this entire project and just throw in a 350 I have lying around. By the time I add that $225 turbo, $400 dyanmicEFI ecm, $300 injectors, I will already have more than what I put into my Turbo SBC.

When I say budget, I mean budget.

fasteddi

iTrader: (2)

If you used 40lbs injectors on a v8 to make 400 hp then you need alot more then 40Lbs injectors to make 400hp on a v6. You making it more complicated then it is.

8 40lbs injectors is 320lbs v8
6 40lbs injectors is 240lbs v6

caffeine

iTrader: (2)

Pick up some used 3800sc injectors and skip the dynamicEFI. If the stock ECM is inadequate swap in a 7730.

Street Lethal

iTrader: (16)

Boost pressure determines horsepower for the individual engine, not every engine collectively. Your budget 2.8 makes 135 horsepower from the factory, so that means at 15-psi you would be making 270 horsepower, and at 8-psi, which is around your target as per you, you would be making 202 horsepower. For anyone to even imply that you would need anything over 28-lb injectors for 202 horsepower, or even 250 horsepower (giving you the benefit of the doubt) for that matter, would be ludicrous. As for budget meaning budget, go with your 350 that you have lying around, there is more to be made without boost pressure with a 350 if you compare the two situations. Your math though is all wrong. I have a set of 6 28-lb injectors that I would have given to you for free, or you can buy them for fifty to seventy five bucks depending on how low of mileage they have, but as far as the ECU, going with the DynamicEFI system would save you money in the long run, but many fail to realize that from the getgo. Either way best of luck...

maitlandtron

I understand boost doesn't determine horsepower for every engine across the board. The engine in question here is a stock 2.8. That is a given. So using boost pressure as a determination for what injectors i would need is still correct. Anyways, that is besides the point. I was also basing the prices on the items that were suggested in the replies.

I don't have any experience with the DynamicEFI system but I have burned my own chips for my TBI before so I might be able to research that and make it work.

Doing the 350 might be easiest option, even though I wanted to do something a little different. Maybe i can track down a pair of junkyard turbos a go twin! haha.

fasteddi

iTrader: (2)

Injectors price. Southbay injectors are good and affordible. I picked mine for arround 150 IIRC their 48lbs.

I also have a set of the 28lbs injectors laying arround that i would sell for shipping cost. Probly the same ones as streetlethal has. If your on a tight budget then get these or his. My car went high 13s before I maxed out the 28lbs injectors. They will keep you happy till you want to upgrade later.

You could always swap in a 7730 ecm and burn off chips just like you would have for the TBI. Since youve tuned that, that might make it easier. But I agree that dynamicefi set up would be better in the long haul. I love my 7730 ecm but then again my car came with it and i didnt have to mess with it much.

If you ran a small turbo 7 psi would net a different HP then a gt3582 or something bigger in the same engine.

Yes a sbc swap might be easier for you, its all about what you want to do with the car. A turbo set up isnt always easy and if you take shortcuts it can cause problems. A motor swap is pretty straight forward exspecially if you going carbed.

Six_Shooter

iTrader: (2)

Not really, while the 2.8 was a popular V6 in the 3rd gen F-body, it's not the only V6 used in a 3rd F-body, nor the only design of one used by our members.

There was the 2.8, 3.1 and 3.8 all in the 3rd gen F-body as stock equipment.

Members here have used a plethora of other V6s, including 3.4, 3400, 3500, 3900, hybrids, and other combinations.

It really behooves you to include the specific information when asking for advice, otherwise all we can do is provide general information, that may or may not be of any real help.

Referring to my previous statements, boost is not a determination of what injectors are needed, EVER. Just because you may have a 2.8, does not mean that the power you are making with your 2.8 at x amount of boost is the same amount of power that someone else is making at the same x amount of boost. Boost is just a measurement of restriction, not of flow. The actual air flow will be different on a completely stock 2.8 than it will be on a similar 2.8 with the only change being ported heads. Change other stuff and the direct comparison idea goes even farther out of whack.

Using the stock ECM or the '7730 are both good ways to get this done. I personally prefer the speed density system that the '7730 uses.

It might be, only you can determine whether it's the right option for you.

maitlandtron

You do realize the title of my thread is "2.8 turbo questions" right?

maitlandtron

I think you guys are missing the point. This was aimed at possible members that have done this to entirely stock 2.8. Maybe the only difference in the setup might be the turbos. That's where the difference in flow restriction would lie.

Six_Shooter

iTrader: (2)

I seemed to have missed that part specifically, but it's better to be succinct about things instead of assuming that other's have all the details accounted for. Many of us read multiple threads and try to help multiple people, so re-stating some key information along the thread is always beneficial to you and the people trying to respond.

The turbo will not be the "difference in restriction", in fact the turbo is not going to have much appreciable effect on boost vs power (as long as the turbo is run within it's efficiency range).

The restriction that a boost gauge measures is THROUGH the engine itself. Change the exhaust, this changes the restriction, change the heads, this changes the restriction. While the measured boost level might not change in these scenarios, the actual air flow will, and that is where things need to be accounted for.

So in reality it's not as simple as stating "a stock 2.8", since there are other external and internal variables that can change the outcome. You can get close to the same results and use the same components as someone else, but no two engines are built exactly a like, so that is where the individual tuning and set-up comes into play.

maitlandtron

I wasnt expecting exact specifications. I beg to differ about the turbo not being a restriction. The turbine has a lot to do with exhaust flow. I have a friend with nearly identical motor specs, with the exception of turbo sizes. He can't wind his motor past 5500rpm due to his restrictive turbine. I think this is becoming more complicated than it has to be.

My question should have been:
Has anyone done a turbo build using a completely stock 2.8. Approximately what size injectors would I need to support about 5-7psi with no other modifications to the motor?

Six_Shooter

iTrader: (2)

And again, it depends on many variables. that people have mentioned in this thread already. It's not really as simple as you want to make it to be.

Also therein lies the problem, you already understand that one turbo vs another can make a difference, so why is it so hard to understand that two set-ups are never exactly alike? The exhaust between the engine and the turbo has a large effect on flow as well as the exhaust after. Since there are no off the shelf turbo kits for these engines or cars, the hot side is different in everyone of them, and that needs to be addressed. Is it a bog difference? Usually not, but it's not as simple as saying you need x size injectors for y amount of boost, it's not that simple with any engine.

If you want a simple answer, then 100 lbs/hr injectors is what you need. That will support any and all boost/power levels you could ever dream of using with a 2.8L...

maitlandtron

So what you are saying is that it's impossible to narrow it down. Thanks. Educated guesses are just out of the question.

project89

iTrader: (1)

for the absolute cheapest way

use the ebay 57 trim or find a 60 trim t3 out of the junkyard
get an adjustable fpr off ebay
and 22 pound injectors out of the junkyard
buy or borrow a wideband o2

plumb the maf to the inlet side of the turbo

on a bone stock engine u will get 7-12 psi out of it. it wont make great power but it will give it a nice lil hp boost

^ that will run on the stock tune , if u do it that way u may need to uplug the cold start injector to get the car to start up when its cold

spend a lil money and do it the right way and that lil 2.8 can make 350 rwhp or better

project89

iTrader: (1)

heres the problem

a 2.8/3.1/3.4 can make anywere from 180 to 500 hp turbocharged
if ur setup is only going to make 250 hp well then u dont need 50# injectors


unless we know exactly what u propse to build its hard to give u an estimate

if ur not going to tune it nd just build what i posted above u only need 22# injectors
that same build properly tuned with ported heads and a cam will make enough power to max out a set of 36 pound injectors

maitlandtron

Thank you. You pretty much covered everything I needed to know. Who knows maybe down the road I can make all those upgrades. For right now, I think what you described will be a great starting point.

Fallen2603

It would be easier if you stated how much power you wanted to make with your set-up. That would be a much better indicator of what size injectors you need to use.

maitlandtron

I'm not chasing a specific number. It's whatever 7 psi on a stock 2.8 would yield. I honestly don't know that answer.

Six_Shooter

iTrader: (2)

And no one else does either. There would be a range of possible outcomes based on many of the factors we've already mentioned.

The most accurate formula here is:

y(2.8l + 7 lbs/boost) = x, Solve for x

maitlandtron

You act as though I expect someone to give me an exact number. I'm not expecting someone to tell me, "oh you will make 252.6587 hp so you will need these exact injectors".

An educated guess based on previous experience with a similar setup is all I could ever hope for.

Project89 answered my questions to my satisfaction. End of story.

Six_Shooter

iTrader: (2)

That's exactly what you expect though, because injector selection is based on power being made, no other way about it.

And while 22 lbs/hr injectors may have worked for someone else on their set-up at 7 lbs of boost does not indicate that the same injectors will work on YOUR engine at 7 lbs of boost, because of the y variables that I posted about.

You can make assumptions that an engine injecting 15 PSIG will have twice the air flow through it that it would at 0 PSIG, which would likely mean twice the power, but that's not always the case, it make make far less or it may make more. Usually in the case of a gen1 660 though it's less than twice the power due to how restrictive the stock heads are, and the point of diminishing returns for increasing boost seems to be about 10 PSIG based on some members experiences here. Some engines because they already flow so well will make more than twice the power at 15 PSIG or less.

Basing HP on boost numbers is just absurd and not a very good way of building a car, ever.

maitlandtron

So tell me how exactly I would know how much power my motor will make? I need to know how much power I will make in order to select the proper injectors. But according to you there are so many variables that I can't possibly know what it will make. So in this situation what do I choose in order to run it and dyno it? I have to have some sort of baseline.

How about I just throw on the 22lbs injectors I have (no cost), gradually add boost and see what the Wideband tells me.

maitlandtron

By the way, to this day I have yet to build an engine based on a specific HP number that I want. I basically build it using what parts I can afford and will work well together. Then, i tune to get best power. I accept whatever the outcome is.

I work with a very limited budget, probably more limited than most on this board. This is why I have learned to fabricate a lot of things myself. I'm not building a NHRA drag car here.

Six_Shooter

iTrader: (2)

Then what does it matter what injectors would fit the application best?

Just slap it together and see what happens then...

Most of us build what we can afford some of us just build more properly than others it seems.

I don't know what NHRA as to do with this...

maitlandtron

Well there's a huge difference between 12lbs injectors and 46lbs injectors. I was only trying to narrow it down. Also, NHRA has nothing to do with this. It's nearly an exaggeration. Meaning none of this has to be perfect.

As long as I'm having fun, that's all that matters to me. I couldn't care less wether you think I'm building my engine properly.

project89

iTrader: (1)

without proper tunning the biggest injector u can use is a 21/22 anyways

u have a pair of them so stick them and in there and run with it , u will need the afpr though

willexoIX

Ok I got confused then, thanks for the correction.

To the OP. I turbod my stock 2.8, but I swapped in an aftermarket ecm. You will make much more power being able to tune it. But the highest inj you can go with on a stock ecm is 22lbs.

I was trying to go the same route as you on my build, in all honesty its a waste of time to do it without tuning... You leave alot of power on the table and eventually I'd bet it would blow. But its your car, so do what you please.

Sounds alot like the beginning of my build thread, lol

maitlandtron

I was thinking eventually just getting an MS2. I would like to burn chips but It is kind of a pain in the ***.

My buddy has a MS2 in his car and its pretty user friendly. When I do that I can upgrade the injectors and get a bigger fuel pump.

willexoIX

Yea I went MS1 running extra, its much quicker than burning chips. I just learned how to tune with my build and picked it up quick. Going to upgrade to MS2 cpu for more control and so I can use my IAC again

FWIW im running 36lb injectors, highest DC so far is 61%. But the tuning ability is a must in my eyes if you want the most out of your setup/don't wanna blow it up.

My first drive I had a 15psi boost spike with a 6psi spring, **** happens, and **** happens quick under boost.

willexoIX

Plus with the MS, no more MAF. I bought the ecm, injectors and harness first, and they were the first to go in. I needed to learn how to tune before I blew my **** up just throwing a turbo on the stock setup. I almost did it that way too, glad I was talked out of doing it that way.

maitlandtron

I want t keep the IAC. That's kind of the deal breaker for me. I definitely want to go with MS2. Does the MS1 have any features for cold start?

willexoIX

MS1 uses the injectors for starting instead of the cold start. MS1 can use a PWM Idle Valve IIRC, but for our iacs we need the MS2 cpu. The MS board version 3.0 is the best buy. With the MS2 cpu running extra youll have plenty to play with. Plus the proto area on the board.

As far as cold start you have priming PW table with temps, afterstart enrichment table with temps, and warmup enrichment table with temps. So between those there really is no need for the cold start injector.

fasteddi

iTrader: (2)

Mabey its because I learned how to tune on chips, but burning chips isnt a pain. Yea i burnt my share of chips back when i started but then again Im running a $59 mask and over at code59 they have some very good starter bins. I think i burnt about 10 chips all year and thats mainly because I switched over to DIS ignition and the hybrid top end deal.

To everone his own though.

If you cant afford to tune it and just want to mess arround and make some extra hp, then you can just use the AFPR route..exc, project89 did it before and knows it best.

These motors can take alot of abuse and torment but just be carful and be mindful of it. IIRC your 2.8L does not come with a knock sensor. So at least make sure you have a good wide band on there and make sure its richer rather then lean.

Not sure if it was stated before but whats the budget you have to toss into the car?

If you start to tune it with a dynamicefi, a 7730 ecm, or MSx in the future with this car or another, keep in mind that you can always tune the fueling down. Oversizeing the injectors doesnt hurt at all to a certaint point because if your buying them from southbay the cost difference between 32lbs and 48lbs isnt much if any.