Building a 3.1 L turbo

[extreme1ont]

sorry im sure there is many topics on this already, but im mixed up between different builds and different opinions. need some pointers in the right direction.....

i have pretty good skills at mechanical stuff, this will be my first bottom to top rebuild and my first turbo engine....

Heres what i have. 1988 beretta... swap... 3.1 L strong great running engine. 5spd getrag. pulled from a 91 cavy. using a 3.1 5spd beretta wire harness.

Im buying a 3.1 turbo engine, stock t25 turbo needs rebuilt.

Wont be starting my project for a while yet, buying the engine from a member here and have to figure out how to go pick it up LOL 10 hour drive.. and still no passport yet  :icon_frown:

My plan is to take the 3.1 L thats in my car now, and use the tgp parts on my block.

1.   .030 bore
2.   new main bearings (possibly over size) ??
3.   new pistons... type ?
4.   cam... ??
5.   new lifters/push rods/valve springs
6.   stock heads.. Port/Polish ?
7.   injectors ? stock ?
8.   t25 stock turbo../ Or upgrade ? t28?
9.   use the 3.1 tgp crank.

I am getting the ECM with the engine but i dont think it will wire in my 88 beretta, can i use my ECM and have a tuned chip burned for it ?

Can i use my N/A wire Harness ?

Tips and suggestions on what pistons / cam /valve springs / injectors / turbo i should use for this build would be helpful

I am hoping for 300 HP, dont want to spend a ton in it but roughly with 2,000 $ MAX budget.

Roughly will cost me $500 to have the block checked, bored, and crank turned for new bearings/cam bearings pressed in. unless i find a cheaper guy to do it. my boss is getting our 350 4 bolt block bored .030 will cost 600 by the time everything is done to it, guy has to send it out to have it done. i have a friends dad who used to build engines but im not sure what equipment he has or still has. but could get good price from him for the machine work.

The turbo with the engine needs rebuilt, i dont know anything about turbo's, if the stock one will do me fine for what i plan on doing and expect from this engine then ill just rebuild it, if i could go with a larger turbo and spend 1 to 200 tops more then rebuilding the t25 then i might go that route too.

I also have a complete set of roller lifters/push rods/ rockers from a 3400 engine, the lifters i know wont work, but will the roller rockers work in my engine ?


anyways thanks in advance for any input on this and ill add more when i think of it, im very tired right now and wanted to get this up quick.

[extreme1ont]

no one ????

[TGP Nick]

If you're wanting 300 HP, then you are definitely going to want to upgrade your turbo.  The T25 is pretty undersized for a 3.1 in the first place.  Its up to you for how big you want to go.  Seeing how you already have a 5-speed, you're a step ahead in the game.. I would suggest upgrading your clutch as well to handle the higher torque being pushed out... the build you're speaking of will make quick work of the clutch intended for a n/a 140 HP 3.1 ;)

If all of those parts are from a 3400, then no, they will not work in a 3.1.  There are however aftermarket roller rockers that will work with a 3.1 MPFI.

[extreme1ont]

i planed on going with a performance stage 3 clutch or something similar. right now i have a brand new.. well 3000 K maybe on it aftermarket replacement clutch put it in when i installed the engine. sat over a year just cuz i didnt need to drive it and insurance was expensive so i drove my boss's truck instead and he paid insurance :) but 30 bucks a day in a 350 carb truck it was cheaper for me to put insurance on my car and only been driving it since August this year.

i dont plan on racing it, might go to the tack just to see what numbers it will run, but i more less want the turbo engine in there more for looks and its fairly rare and would be different then most beretta's.

But since i am going to rebuild it, i might as well do it the right way the first time and not just slap it together and hope it last more then a few miles. since stock is 205 HP i figured 300 wasnt far off and should be a good goal to reach.

I figured if im stripping it down and put in new pistons that way i know its good, i might as well have it bored at least .030 even to freshen it up and would add a tiny bit more power.

I know nothing about turbo's at all, and never moded a 3.1 before. so looking for some suggestions on what is a good cam to use, what type for pistons for a .030 over bore and will give me a good compression ratio to work with the turbo on it. im sure i wouldnt want to bump the compression up too much since im going to be forcing air in, a lower ratio would be more suitable ?

What type of injectors or flow # would work best.. is there a stock injector from something else i can use that i could find at the junk yard.

i prob wont go tooo crazy on the heads, maybe take the dremel and clean off the rough areas in the ports to clean it up and get a tad more flow but i dont want to spend a ton at a shop to have them fully ported, prob not a drastic HP gain with porting using a turbo ? since your forcing air in its going to flow no matter what.

I will have to upgrade my exhaust as well, 3 inch all the way should be sufficient ? its got 2 1/2 inch now. and i have to keep the cat for pollution test here in Ontario. it just passed the pollution test in august and wont have to be done again until i renew my permit in 2012 since the test is good for a year and i have to renew it in February so ill have a full yr after this coming February before i have to worry about the pollution test again.

i still have the factory 2.0 L emblems on the car. i see people all the time staring at the emblems, when im at the gas pumps sometimes i stop at this 1 place cuz its cheapest around its full serve and the young guy was staring at those 2.0 L emblems the other day i noticed him glancing at it a couple of times and when i left i honked on it pretty hard, he musta been thinking holllly crap that thing goes and sounds pretty sweet for a 2.0 L  .. LOL

people will really wonder whats going on when the turbo is under there and im peeling rubber through every gear as i pull away.


Anyways.... if i bore it .030 and a decent cam, what size turbo would work the best ? and im not going to spend much more on another turbo then it will cost to rebuild the t25, so something used would be good.

I was kinda figuring on the numbers like this.. the stock turbo engine was 205 HP, ive herd with a good tune you can jump that a fair bit, so with a little bore, a good cam and different injectors along with a good cam i figured even with the stock t25 i should be able to get some decent numbers out of it. maybe not 300 HP but theoretically 250 to 300 should be easy to achieve.

If i was going for like 400 plus hp i would consider a much larger turbo of course but i would have assumed the t25 would work fine and its going to be a daily driver car not a pro stock race car. 300 hp should be enough to make a little sleeper out of it and be good to drive around town and some highway.

[mfewtrail]

My advice: Forget the turbo engine altogether. Take the NA 3.1 and throw the turbo parts on it + a slightly larger turbocharger. You do not even need to touch the heads or cam to make 300hp...

[Dark Ride]

I've heard goods things about the H260 cam, although I've never owned one.  1.6 Ratio Rockers are really easy for a couple HP.  But if you are looking for 300 HP you will probably want to look at upgrading the turbo.  I believe Krenzy/Grinders 18 used a GT28 as a bolt-in replacement.  I believe that a 2 1/2 inch exhaust was sufficient for a 3.1, that 3 inch was overkill (Although it probably doesn't hurt either)

Look for GutlessSupreme's TSTE Rebuild thread over on W-body, he went through the motor on his, sounds similar to what you want to do.  You may find some good information in that thread.

[extreme1ont]

thanks, ill search for it

[flybynite]

The recipe is simple.  GT2871R + 30-36lb design III injectors + a good tune = right @300hp. Like all ready mentioned the stock engine will be fine...

[Dark Ride]

Was the GT2871R a bolt-in replacement too?  It's been a while since I researched turbo upgrades.

[Penglii]

Here is the link to a thread regarding GT2871R install:
http://www.tgpforums.com/index.php/topic,4929.0.html

[flybynite]

The hybrid was built utilizing the stock journal bearing center. So no mods required other than the injectors and tune.  The one from kens build  was ball bearing and needed a fee tweeks...

[extreme1ont]

i kind of want to keep it simple as i dont know anything about turbo's but if i have to fab stuff to make something fit i could do so.

And the reason i would bore the block because i have the engine in the car now 3.1 N/A and buying a near complete tgp engine, my car will be parked for the winter and i have a shop to work on it.

If im going to do the turbo swap, id really like to do the bottom end as well even if it were stock rebuild on the bottom end, so i know its good, no point in putting all the turbo stuff on and half way into next summer it spins a main bearing or throws a rod.

I will own this car for ever and i dont want to be pulling the engine all the time to fix stuff. id rather do it right the first time and be done with it.

The reason i was thinking about boring the block, is more less to freshen the cylinders up, i was told the 3.1 i bought had 100,XXX K on it and about 4000 that i put on it and some of those are pretty HARD k.

Like the other day on my way to work, this cavilier in front of me all over the road so i passed him in 4th gear just blew by him and got on the binders after i was around him cuz i was doing like 60 over the speed limit. and next thing hes coming up beside me passing me so i got back on the throttle still in 4th and hes gaining on me so not even thinking my first reaction was to down shift and floor it not even realizing how fast i was already going. so i slammed it in 3rd and looked down and the tach was like way over the end past 8 grand i was doing 140. i quickly shifted back into 4th and right on his ass, if i had noticed him coming up behind me i woulda had him but i was on the brakes slowing down as he was coming beside me.

The engine still sounds brand new, not a single tick or nothing out of it. but its had a rough past 2 months LOL.

so everyone says dont even touch the bottom end and just go bigger turbo. for the price difference in new pistons for over size starts at 50.00 ish more on summit. for the few bucks more, i could maybe gain a few more hp and know that my bottom end will hold together and last me a long time.

So lets look at the turbo. if i dont get 300 hp im not worried. anything more then the 140 it has now will be a gain lol. i was just using 300 as a start assumed it would be easy to reach.

If i go with a bigger turbo id like something not expensive and bolt on.
there is a chart of different size turbo's here.... http://www.ztechz.net/id1.html

the T28 is 43 cfm larger.
GT28RS  130 cfm larger.

Stock T2 is 405 cfm.

not sure if the outside diameter is larger on a bigger turbo or just the turbine and inlet and outlets. but its going into a 1988 Beretta so theres not a whole lot of room to start with, i have to fabricate a 5speed tranny mount that goes to the frame rather then at the top right were the turbo sits, i also planned on putting the intercooler in front of my rad somewhere so i would have to re locate my battery for room to run the piping.

How does the blow off work on these turbo's ? can you put an external one on it ? i want it to whoooooshhh every time i let off and change gears.

[mfewtrail]

so everyone says dont even touch the bottom end and just go bigger turbo. for the price difference in new pistons for over size starts at 50.00 ish more on summit. for the few bucks more, i could maybe gain a few more hp and know that my bottom end will hold together and last me a long time.

The stock bottom end will hold up fine as long as you get the car tuned decently. Machine work to rebuild an engine can get very expensive!

[extreme1ont]

my boss is having a 350 4 bolt main sbc bored .030 and the tanking and pressure checking and boring, and pressing in new cam bearings, basically ready to assemble, is going to be around 600 but no more then that, and the rebuild kit for the engine is around 400.

i figure on a v8 hes charging 600 to do the machine work, so a v6 should be a little cheaper as its 2 less cylinders to do. the guy has a shop in the country and has been building engines since he got out of high school and hes gotta be between 40 and 50 now. i kinda thought that was a bit expensive just to bore it but i guess with doing the cam bearings and cleaning the block and all the extra small stuff its not bad, and hes very well known in the area, everyone recommends him. i am not 100 percent that he build the engine in a late 60s vett in town but i know its a 7 second car and street legal. the guy knows what hes doing thats for sure.

Does anyone know where to look to get a chip burned for my beretta ECM ? the ECM is from a 91 car. it has a long narrow chip that unplugs from the ecm. i think on wottech they sell them. not sure if they can turn it for a turbo setup.