Turbo'd 3.1ltr

[Guest Kahamri]

I bought a carbed z28 with a 350.. comes complete.. i have a 3.1 ltr rs now.. and eventually i'd like to swap the 3.1 for the 350.. easy swap.. i can do it.. my quesion is.. I want to turbo the 3.1 while it's in the car.. I wana put a big 16g on it.. Ported and cliped.. I know my engine wont handel it now.. At the most i'd like to run 18 boost.. i could probaly be happy with 15.. How hard would this be.. I've been thinking about it... i know i have to build the engine.. I dont know what to do to the engine to be able to handle this.. The manafold i can get.. The turbo.. intercooler.. piping no prob.. I know i needed to upgrade the injectors.. the fuel pump.. probally the lines.. anything i'm missint.. i mean i dont know what else i need to do.. NEED TO.. not can.. like i CAN upgrade this vs. i HAVE to upgrade this.. any help?

[Guest project3.4camaro]

turbo on a 3.1? Knoble idea but it won't be easy. The crankshaft might be ok, but the pistons and connecting rods might give u grief. Those have an 8.5 or 9:1 compression ratio which is a little high for a turbo. U would need lower compression pistons, prolly forged just in case. U said it was carbeurated? It it is that'd make it easier, but u would still have to rejet the carb to give it the extra fuel. U don't want it to run lean. 18 pounds of boost would be a little much, but it's ur car. Lemme get this part straight. Ur taking the 350 out of the Z car, dropping in the 3.1, and then turbocharging it? just wondering what tranny and diff u will use. Anyway, just a rebuild wiht lower comp pistons and a stronger bottom end with bigger jets should be close. Im no expert at this of course, I have just made a plan to try and turbo my 3.4, which is closely related to the 3.1 adn that's part of what i came up with. There should be a book available, a how to kinda thing. I have seen it on ebay before. Just my $.02. Even if it was darn near a novel....

[Guest Kahamri]

I'm sorry.. i dont think i was very clear.. let me clear it up for ya..The z28 is another car i just bought.. not of importance right now.. I have a 3.1 ltr rs.. I want to tubo it.. Already has the taray and diff in it...if i was to say run 8 or 10 psi.. what kind of hp increase do you think?

[recklessOP]

Originally posted by project3.4camaro:

Those have an 8.5 or 9:1 compression ratio which is a little high for a turbo.

 

why would you want the compression ratio any lower than that? that should be perfectly fine for any street turbo setup...

[recklessOP]

i don't know much about that particular engine, but i would check into what other people have done first...

 

you can always beef up the internals, and upgrade the fuel system, but some engines are simply not designed to handle the stress of forced induction. if that particular engine was never turbocharged (or supercharged) from the factory, there's several things to look at first...

 

my main concern would be with sealing the heads to the block. i don't know about your particular engine, but some motors are notorious for head sealing problems, and boost will only add to the problem...

 

the strength of the block would be another concern. not an easy problem to address. make sure the block can handle the additional horsepower...

 

like i said, your best bet is to look at what other people with similar projects have done, and copy what they have done. if you're not looking for any huge power gains, then the engine should be really be fine. most factory engines are engineered to survive a fair amount of extra power than what they produce in stock trim...

 

[ 05. June 2003, 04:49 PM: Message edited by: Rotary Mustang ]

[Guest project3.4camaro]

he wanted to run 15 psi when iread the thread, which is a lot for an engine with that high of compression. 8-10 pounds would be fine with that compression. Take the toyota supra and 300zx. both the turbo'd cars have low c/r around 8-8.5. That's for a very strong inline six too. just a thought.

[recklessOP]

talk to mark, aka dremel, he knows turbos better than i do... tongue.gif

 

[ 05. June 2003, 04:16 AM: Message edited by: Rotary Mustang ]

[Hwilli1647545487]

I see two issues with this thread.

 

First I see a guy giving advice when he obviously shouldn't be.

 

8.5 compression ratio is fine for a turbo application. As is 9:1. Many Turbo DSM guys will swap in the N/A motor short block for a little more low end (due to higher compression), and still run high boost. The only thing I am going to agree with you is "You might need better rods/pistons, but this is purley speculation as you obviously don't know the specific capabilites of the 3.1L he is using.

 

Now on to the initial question.

 

What maked you pick the specific turbo/engine/boost levels you are discussing?

 

My guess is it's because you have easy access to those parts, and have heard that some other cars push that much boost on some other motor. My ADVICE is to do a LOT of research on your motor, it's capabilities, and then go from there.

 

As previously stated you are probably going to need a built bottom end to run that much boost... though I do know that there was a factory turbocharged 3.1 in some Grand Prix, I don't know how much boost, or its specs... Also are you sure that turbo is a good match for the motor? It might be.. I don't know, and I am not doing your research for you tongue.gif

 

or you could go the deep pocket route. Bolt everthing up, crank the boost and see if it blows smile.gif

 

 

Ok I just went back and actually read your post.

 

What you would NEED (IMO). Built shortblock. custom made manifolds/collectors. Turbo, and a fuel system. I would also RECOMMEND( but you said need) an intercooler of some sort, and all related (and probably custom made) piping.

 

HTH,

 

Sorry if I sound cranky. 2 more hours left in my 12 hour night shift smile.gif

 

Howard

[SupraGlue]

Originally posted by Isolationist Monk:

I see two issues with this thread.

 

First I see a guy giving advice when he obviously shouldn't be.

Pot.kettle.black. tongue.gif

 

Static compression comparisons between motors with different head designs and cam specifications is MEANINGLESS.

 

Is that V6 an iron head motor? If so, that greatly affects in an adverse way the onset of knock. Aluminum heads are going to be more tolerant. What is the chamber design like? Pent roof? Wedge? What is the squish area? What cam grind will you run? All of those issues will affect how much power you can make under boost before the onset of knock more simple than static CR. Same goes for the efficiency of the compressor/intercooler combination that you will run. The key here is the mixture pressure and temperature within the cylinder -- that is what will cause detonation. Static compression is only one factor in the entire equation. There is a reason it is called "tuning". smile.gif

 

Now, in terms of mechanical strength of the motor, you will need to understand how well the heads seal -- will simple copper head gaskets survive, or will you need to o-ring the deck? Are the head bolts of sufficient number, placement and design to prevent the head from lifting? How thick is the deck of the head and block? What about main bearing area and the strength of the main bearing cap bolts? There is more to building a good turbo motor than just pistons, rods, crank when you are starting with an NA design that may never have had boost intended for any variant of it.

 

Your valvetrain will also merit a look. Increased cylinder pressures means increased stress on all valvetrain components. You may require stiffer valve springs, and strengthened pushrods. Rocker arms will also be something to consider, in terms of the rocker and stud flexing.

 

You are also going to need to consider some other areas where weaknesses can show up. Front and rear main seals are one such area. A boosted motor is going to see more crankcase pressure, so leaking or blown out seals become more of a possibility.

 

Now, this part is just my opinion -- for some of the reasons above, I take a dim view of turbocharging NA motors, when there is a suitable factory boosted motor available. In your case, there is.

 

Both the 3800 Series II Supercharged and the Buick LC2 3.8 turbocharged motors are readily available and swapable to your application. These motors in near-factory trim can make very nice amounts of horsepower. If it were my project, and it is not, and I had the ambitions that you do for boost level, I would strongly consider those options. They are also well-worn paths, and the performance recipies for them are tried and true.

 

If this is your first experience with turbocharging, I would strongly recommend taking that route.

 

Now, driveline is another matter, and I'm assuming that you know that you will need to bring your tranny, etc. up to snuff for your new power and torque level.

[recklessOP]

this is all way too complicated... tongue.gif

[Guest 614Streets]

ah the 189 , the 3.1 liter 60 degree gm v6.

3.5 inch bore with a 3.31 inch stroke.

On a rs its a mpfi , iron head motor , screw in studs , factory guideplates, 1.72int , 1.42 exhaust valve , rated 50cc unshrouded combustion chambers with an intake bump inside the intake runner which increases the port flow by 23% , its not a smog bump.. The motor is entirely metric , like all gm 60 degree v6's.

 

On a rs 3.1 the factory pistons are a slight dish with no valve relife. appx , 8.9:1 compression.

 

 

Rod lenth is 5.7" , on the 3.1 the engine is balanced internally and uses the same reluctor timing throw equiped crankshaft as the fwd versions minus the timing notches. 3.1 rs is a distributor equiped engine unlike the mpfi fwd.

 

Personally If you have a little cash to play with and you would enjoy having the 60 with a turbo , the route I would go is hybrid.

 

The Newer 3400 sfi engines have the best flowing heads(genIII) and use Sequential fuel Injection(not batch fire). The also have great intake design.

 

The 3400 SFI uses aluminum heads, with canted valves , screw in studs , guideplates ,with appx 28cc heart shaped combustion chambers.

 

3400 uses dished pistons. (** for perspective** 3400/3.4 is a 3.620 bore and 3.31 crank, same crank and rods as 3.1, all 60's use the same rod, 2.8 ,3.1 , 3.4 )

 

For either a mpfi stock vin rs 3.1 motor with a turbocharger or a 3.1 hybrid , even a 2.8 hybrid(2.8 is 3.5 inch bore by 2.99 stroke , uses same rods), and thoose boost levels custom forged pistons are a must. the crank will be fine and the rods might as well be fitted with the arp units for the 60 degree. With the Iron heads arp offers studs, but not for the aluminum head motors.

 

The best gasket other than custom copper for the 60 v6 is the mr gasket solicor line made for boosted / gassed 60's.

 

As far as cams go , with the aluminum head 60's Gen II or III , a hyd factory roller is used , however , no cam company offers anything but regrinds , PERIOD! No core, and probably never!

 

The Iron head engines are fairly supported with all four types of cams hyd/solid flat tappet as well as hyd/solid roller.

 

On a iron head motor you can flip the factory exhaust manifolds upside down side to side for GN like turbo routing, or like a td06 twins on flipped manifolds.

 

 

Review

</font>

• Forged pistons, also means rods need bushed</font>
• Moly Rings</font>
• Arp Rod Bolts</font>
• Double chain (cloyes)</font>
• Custom cam or crane 272 *112 centers</font>
• Solicor gaskets</font>
• Have engine machined,balanced,cylinder bored,line bored,ck 10 , etc.</font>
• and the obvious , things like fuel and ignition/ecm tuning</font>

Thats all off the top of my head for now.

 

My entire suggestion. Reasearch it out.

and head over to http://discussions.gmforums.com/forumdisplay.php?s=2e169a028c089fbc3f093adb579d9927&forumid=263

 

and check out http://60degreev6.com

 

for a look into a custom turbo 3.1

head to www.turboz24.com

 

Lastly , think about the cost to do it right , It wont be cheap to make it fast. And do you really want to try to spend money on any v6 instead of a v8?

 

 

READ READ READ. Research Research Research.

 

http://www.columbusracing.com/ubb/icons/icon5.gifHidden trivia: Whats the nickname for the newest gm 60 degree v6 engine the super high tech 3.6

 

my aim is W614streets if you have any direct questions.

 

[ 05. June 2003, 06:23 PM: Message edited by: 614Streets ]

[SupraGlue]

Nice post, Will. I figured you'd pop in here at some point with some real answers. You know that V6 cold. smile.gif

[Guest Kahamri]

Cool.. I'm not really worried about blowing the einge.. i know i will eventually.. I'm starting low boost and working my way up.. I knew i was geting forged pistins.. fule.. timing.. incnition.. I wasnt sure about the rest.. I dont know much about this engine.. I'm jsut starting the project.. The reason i'm not too worried about it is because i just bought an idenical z28..the body is shot and the intioir is shot.. BUT it's got a nice 350.. comes with everything and runs great.. so i can swap this in the rs body.. now i'm starting to think i should just turbo the 350.. but how hard would that be? I really dont want to blow this one.. hmm....off to do some reading

[Renner]

Originally posted by Dremel:

Pot.kettle.black. tongue.gif

Ahem, reading a bunch of books or internet threads about engine building doesn’t exactly make you a guru either. tongue.gif

 

 

Originally posted by Dremel:

Static compression comparisons between motors with different head designs and cam specifications is MEANINGLESS.

Actually, I am going to have to disagree, where did you come up with this theory anyway? The compression ratio is the single most defining factor to the ultimate combustion chamber pressure, and should be the very first parameter used to base the performance capabilities off of, for a given bore, stroke, and rod length. How are you going to figure a combustion chamber temp, and thus an engines ability to resist knock, based on the fillet size used on the piston dome for example? Also, it is very difficult to change the quench volume to the point of excessive out of control pre-detonation without significantly influencing the CR, so in this aspect, with a stock internal engine (no monkeys making changes to quench area), the CR should once again be referenced first and foremost. I wouldn’t exactly refer to the CR as static either, since it is anything but static. The number you are referring to (9:1 for example) is actually the maximum CR seen during the cycle, and could only be considered static if it were constant throughout the combustion process, which it is not. I do not consider 9:1 a high CR at all, several of the NA engines we built at Auto Assets were running 13.75:1 or more for compression ratios for endurance engines, and on regular old Turbo Blue leaded. Those numbers I consider high.

 

The other things you mentioned are of course causes for perturbation points of pre-detonation, and should always be taken into account when designing a better engine. But they are not the defining factor to what kind of cylinder pressures the engine can handle when running correctly, or if it could be converted to FI or not. They are actually a very small percentage of cylinder pressure and temperature fluctuation when compared to the total amount of temperature and pressure change from the compression and combustion processes alone, but which usually are the small things that push the thermodynamic process over the edge past the point of safety. For example, if he has iron heads, he should run a better intercooler to lower the charge temp, not swap the heads for an aluminum pair just due to their better heat transfer coefficient, because it will be a much smaller percentage change in cylinder temp/pressure when compared to the difference made by the lower charge temp from the better intercooler. Aluminum having a better heat transfer coefficient isn't the deciding factor in head materials either, steel has a higher thermal capacitance then aluminum, which is a very good thing in certain cases. The CR is the same in this way, lowering the CR (if needed), and thus changing the piston shape, will give you many more benefits in terms of pre-detonation prevention then changing the shape, material, or valve size of the head will ever do.

 

The ideal piston for a quench type chamber would be a flat top design, which did not have any kind of dome protruding into the head chamber, which of course dictates a lower compression piston just due to the flat top shape. This reduces the area of the piston head to a minimum, reduces the amount of combustion heat absorbed by the piston, and eliminates combustion inconsistencies created when there is a large cone section separating the chamber into irregular cavities. Any sort of piston dome will cause compromises, since the flame front cannot spread smoothly throughout the chamber.

 

A low compression engine is going to have more of a flat top type piston, good for pre-detonation prevention, and a high compression engine is going to have a dome shaped piston of some sort, prone to pre-detonation issues. Soooooo, the compression ratio tells you way more about the internal geometries of the combustion chamber and its capabilities then you think, because the CR is almost completely governed by the shape of the piston, assuming you haven’t done anything wacky with the combustion chamber and quench area (which he hasn’t on a stock engine).

 

With the proper tuning (i.e. timing, fuel, no excessive backpressure, etc.) and an efficient enough intercooler, (low enough charge temp), I don’t see any reason why you couldn’t run 15 psi on bone stock internals with no knock on almost any car with a 9:1 CR, assuming your internals were strong enough to handle the loads of course.

 

[ 06. June 2003, 02:30 AM: Message edited by: Renner ]

[SupraGlue]

Case A:

 

Iron head motor, block first cooling, wedge chamber, low quench area, high quench height, 11:1 static compression, 272 degrees of intake valve opening on a 114 lobe center (wider lobe center means slighly earlier intake valve closing point). Knocked on 94 octane gas unless ignition timing was retarded. (That's a motor I built in 1988)

 

Case B:

 

Aluminum head motor, head first cooling, pent roof chamber, high quench area, tight quench height, high swirl chamber, 11:1 static compression, 292 intake duration cam, longer rods. This motor will likely run all day long knock-free on octane in the low 90s with full timing advance. (That is the motor I would choose to build in 2003)

 

Now, I'm no guru, which we know because I have never worked on a Porsche , but it sure seems to me that engine B has less inclination to knock than engine A at the same CR.

 

I don't know. Maybe all that stuff I read about dynamic compression just confused me. tongue.gif

[Orion]

wow, the tech section is fun.

[Renner]

Originally posted by Dremel:

Case A:

 

Iron head motor, block first cooling, wedge chamber, low quench area, high quench height, 11:1 static compression, 272 degrees of intake valve opening on a 114 lobe center (wider lobe center means slighly earlier intake valve closing point). Knocked on 94 octane gas unless ignition timing was retarded. (That's a motor I built in 1988)

 

Case B:

 

Aluminum head motor, head first cooling, pent roof chamber, high quench area, tight quench height, high swirl chamber, 11:1 static compression, 292 intake duration cam, longer rods. This motor will likely run all day long knock-free on octane in the low 90s with full timing advance. (That is the motor I would choose to build in 2003)

 

Now, I'm no guru, which we know because I have never worked on a Porsche , but it sure seems to me that engine B has less inclination to knock than engine A at the same CR.

 

I don't know. Maybe all that stuff I read about dynamic compression just confused me. tongue.gif

You are missing the point of what I was explaining. As I said in my second paragraph, of course the complete setup specs of the engine all sum to aid or hinder pre-detonation control, I never even implied that they didn’t. But when you said that the CR of the engine is meaningless when it comes to an engines ability to run boost safely without pre-detonation, then that is where you are incorrect. The other factors are only a very small percentage of what causes the elevated cylinder pressures and temps that actually allow for the combustion process to take place in the first place, or which may push the engine past the point of safety. That is why we use compression in the first place......

 

If the CR of an engine didn’t matter in terms of temperature increase, and thus possibility of knock onset, why are you even mentioning what CR you will be running on the new engine? Why not just build the aluminum head motor with a 13:1 compression instead, since the CR obviously doesn’t matter for knock control, and since you have taken all of those design measures to help combat knock?

 

Also, how can you possibly know the true CR of an engine you haven’t built yet? You can’t, you have to use the numbers given with a certain target CR in mind to begin your build process. You design the engine for the target CR first, and then modify the remaining parameters from there based upon your tolerance at that CR, or make small modifications to reach the desired CR. How can you know the volume of the combustion chamber you want without knowing what kind of CR you are even aiming for?

 

It sounds to me like you are quoting the given numbers for only the pistons that you plan on using. That is not the CR. Is that how you determined the CR of the first engine also? You cannot know the actual CR until the piston and combustion chamber volume are measured and calculated together. How can you try and predict what octane the new engine will run on until you have done it yourself, here in this atmosphere in good old C-bus? If you built an 11:1 NA engine that knocked on 94 octane, then there was something significantly wrong with your setup/tuning, hence my comment about having a stock internal engine(which is what this thread was supposed to be about), where the quench volumes for example were still intact per the designs of the GM engineers. Do you know more about combustion dynamics then the guys who designed those engines from the ground up? I know I sure don’t. And I am willing to bet that there are plenty of similar setup 11:1 CR engine around that had zero detonation problems.

 

And yes, the CR of an engine is in fact dynamic, not static. So if you want to talk about the actual CR of an engine, calling it static is not correct. You may be referring to the theoretical CR of an engine, which is what the numbers given to you by the piston/head manufacturer are. Then there is the measured max CR of an engine, which is what you find when you CC the combustion chamber, etc. These are the numbers we are supposed to be discussing here, because those are the numbers measured and listed by the engine manufacturer. But the actual CR of an engine, which is what I stated was the “single most defining factor to the ultimate combustion chamber pressure” is in no way static, because it is rpm dependent among many other things.

 

Come on Mark, I would have expected you to know this!

 

This is a very difficult array of numbers to figure out, and requires some extensive testing of an engine, but it is also the most useful. Since pretty much none of us here will ever do the data compilation for the actual CR number (requires a serious research environment), then the closest thing we can go by is the measured max CR. This is a good assumption, since the actual CR is a completely reversed harmonic process, offset so that the upper bound wave limits lie just slightly above the measured max values, but with the lower bound wave limits well below the measured max values.

 

 

BTW, you don’t need to work on Porsches to be a guru, but I would assume that such an expert engine builder who has been doing it since 1988 would be a bit more adept at doing some of the work on his own car, like changing spark plugs, replacing suspension pieces, etc.... tongue.gif

[recklessOP]

Do you know more about combustion dynamics then the guys who designed those engines from the ground up?

when it comes to old GM passenger car motors, i would say yes. not every engine is built like a porsche... tongue.gif

 

i don't think you realize just how low tech some of these older, mass produced GM engines are. remember, everyone's favorite small block was designed in the 1950s. they aren't exactly precision built either... tongue.gif

 

If you built an 11:1 NA engine that knocked on 94 octane, then there was something significantly wrong with your setup/tuning

how many small block chevrolets have you built? tongue.gif

 

 

good thread, keep it up...

 

[ 06. June 2003, 06:35 PM: Message edited by: Rotary Mustang ]

[Hwilli1647545487]

This is a very difficult array of numbers to figure out, and requires some extensive testing of an engine, but it is also the most useful. Since pretty much none of us here will ever do the data compilation for the actual CR number (requires a serious research environment), then the closest thing we can go by is the measured max CR. This is a good assumption, since the actual CR is a completely reversed harmonic process, offset so that the upper bound wave limits lie just slightly above the measured max values, but with the lower bound wave limits well below the measured max values.

[Guest project3.4camaro]

FIrst off, The 3.1 60 degree engine is a derivative of the 2.8, as is the 3.4. The 60 degrees are notoriouts for blowing engines and that is NATURALLY ASPIRATED. Sure, go ahead and turbo that sucker with any CR above 8.0 and let us all know how many miles it takes to blow the fucker up. THose motors have horrendous problems bc kthey were originally designed for ultra compact engine bays, i.e. The Cheverolet Citation, FRONT WHEEL drive, thus they ddin't have enough room to beef it up. And if you would have read what I had said, I said that is what I would do, not out of a manual, Isolationist monk graemlins/asshole.gif . Personnally, I don't want to blow a motor in 30000 miles. And yes, i know all about the capabilities of a 3.1 motor, and even though they are overlooked as high performance motors, a block as old as that one is, with the same compression, U WILL BLOW THAT MOTOR QUICKLY.

[recklessOP]

i will agree, the 2.8 sucks...

 

my S10 has one...