Turbo plan/questions

[Poor_S13_Driver]

Hello all. Im a long time reader. and finally decided to register. Im driving an 89 SX. I am madly obsessed with 240's just like everyone else im sure. I plan on going turbo next winter. Ive tossed around ideas about SR's and RB swaps, but ive finally realized thats unrealistic right now, and am becoming very intrested in the KA24e motor. My target would be 325-350 WHP. I will have about 3 grand to play around with. My entire goal is for it to be RELIABLE. I dont want to have to yank the motor out and rebuild it every year. Hers my plan. hear me out and add or correct anything i say. I think one of the best things to do it get lower compression pistons. While I have the motor out I would replace gaskets and make sure everything is fresh. Then would come the turbo and i assume a new Intake manifold to accept the turbo?. I want a nice responsive turbo. Then all of the other little things that would go with it BOV etc. Im not quite sure what to do about Engine Management. I dont know what to do as far as Injectors and ECU. Does this sound realistic for 3 grand? Im kinda a noob to turbo cars and what goes into making them tick...right So i appreciate any little sliver of information. -lyons

[fiznat]

I think 3 grand is really cutting it close with a built motor, but I dont think it is entrely unrealistic. You'll have to find good deals on all of your parts, get them used if possible-- and find a machine shop that is willing to do all of your work for a good price. Plan on spending $500 for pistons, at least $1000 for machine work (including a full balance, shortblock assembly, new bearings, nice gaskets, deck the block, new rod bolts at least, etc)... That's half your budget right there and you dont have any other parts. It probably COULD be done for 3000, but definetly not with all brand new parts-- you're going to have to get used stuff. I dont know if you feel like that cuts into your reliability goal, but for your budget I dont think you have any other choice.

Good luck man!

[Structure240sx]

for a system to get you to your HP goals is only possible on a stock motor. this can be done with the right tunning. there sno way you will be able to have a built motor and turbo kit within your budget.

you should take more time to save and learn. the turbo does not go on the intake manifold, it goes on the exhuast manifold

[mkory]

I'm not positive, but I think he brought up the intake manifold thing because he doesn't realize that you can run pressurized air into the stock intake manifold.

[Poor_S13_Driver]

Fiznat Thank you for your useful reply. The only reason why I brought up New pistons was to lower compression, because from my understanding the stock compression is a titch to high(if you plan on using lots of boost which I may or may not do) thats the only reason I brought that up to support my reliability needsThank you to the others that replied I greately appreciate it.

[crzycav86]

I say start with lower, more attainable goals.

For $3000, you can have 250 reliable hp. Hell, you could have a basic reliable setup for $2000 if you wanted less power, and cheaper parts.

It's your call, but don't get in over your head.. because that sucks, I know:(.

[hannibal]

You dont NEED to build your motor for 350whp. There are guys making over 350whp on a stock motor with stock comp ratio. Tuning is the key to making those high numbers. Of course, forged pistons with lower comp ratio is 'safer', but not entirely necessary.I dont know the mileage or age of your engine, but I would suggest running the turbo without building the motor. For now, I would spend that money on a good turbo setup (check out http://www.boostdesigns.com) and maybe a clutch. If you decide to up the boost (to make 350whp), then you can start worrying about pistons, etc.

[TheOne]

get $4000 and get the stage 3 boostdesigns kit, and SAFC II or better to manage all that fuel.(not sure if the SAFC II will do the job though).

[Structure240sx]

too bad that stage 3 kit doesnt include the machine work to get those pistons in.

[hannibal]

Honestly, for 350whp, I think $1500 is better spent on engine management than pistons, rods, and machine work.Ivan at SPRacing/Phat-KA.com sells the AEM EMS for about $1800. He's made over 400whp using the AEM standalone.I keep hearing over and over that detonation is the #1 killer. If you detonate with your new forged pistons, they will still be damaged. I think good tuning is more important than forged internals.

[AustinSilvia]

you can do a lot with $3000. a whole lot, as long as you shy away from being stupid with your money. you need to forget about getting name brand parts right now. greddy's kit alone costs more than your budget allows. on that note most kits out there are over priced. you can piece together a decent kit for $1500 easily. ebay is your friend. then you have $1500 for machine work and what not. it will be cutting it close for sure but it's do-able.

i do have some questions though... do you know how much 350whp is? have you ever even stood next to a car that has that much power? i'm not mocking you, however that was a joke. but here's something i think i have discovered as a pattern... whenever someone gets on and starts talking about numbers they want to put down instead of just focusing on getting a more balanced car or something more realistic it usually never happens. i see too many people that talk numbers and have no conception of what the numbers really mean, unless they truly are dyno whores.

anyway set your goals to building and balancing the engine and putting on a modest turbo kit to start with. fuel managment will then be something you can upgrade over time and while you upgrade your fuel managment you can turn up the boost with a nice little $10 manual boost controller. you can save money on everything but fuel management. if you try to be skimpy there you will have a toasty engine and you will be out $3000.

anyway i'm just trying to suggest here that your goals are not completely out of range, however it may be wiser to go about attaining them in a different way. just my two cents.

[mkory]

Okay, well I'm sure his next question will probably be the same as mine, since we're both pretty new to turbo. I understand the concept and function, but maybe not all the parts.

So here goes... When pieceing together a turbo kit, what all would I need to round up? I know I'd have to get these parts:

exhaust manifoldturbo (probably a t3 or t3/t4)maybe an intercooler if I could find one cheapBOVWastegate

I'd have an exhaust shop around here do the pipeing for me. I don't really understand how manual boost controllers work or what waste gates do (vent exhaust, but why would you need to do that?). I also dont know what controls the BOV. I've searched this before, but it seems like the KA-T section is pretty advanced for me, along with other newbs to turbo, and can be kind of intimidating.

Thanks,Mike

[nissanfanatic]

I woudn't think 350whp would be reliable on stock pistons. And $3000 isn't gonna get all the hardware plus the tuning hardware to put numbers like that on the ground. Yet another problem, if you start out with low numbers, you'll find that traction becomes an issue at any amount of boost on a KA. So throw a LSD and a clutch in the basket. You may want to consider tires as well. It can be done for $3k, but how long do you want it to last?

[hannibal]

Here's a list I made when I started learning about turbos...

Turbo List

turboturbo exhaust manifoldwastegate (if turbo doesnt have internal wastegate swing valve housing)

downpipe (connects turbo outlet to cat/test pipe) -turbo outlet flange -piping -fittings (O2, wideband O2, EGT) -wastegate return pipe (from wastegate outlet to downpipe)--external wastegate onlytest pipe (takes place of cat, connects downpipe to catback exhaust)catback exhaust (mandrel bent) -piping -muffler

larger injectorshigh flow fuel pumpfuel management (piggyback, JWT ECU retune, hacked MAF)ignition management (timing retard control)--over 8 psi

intercooler (front mount)-IC piping (mandrel bent)-silicon hose couplers and transitions

BOV (with flange of same material as IC piping)

oil supply kit -oil pan bung -braided oil lines -oil line fittings -'T' fittings

water/coolant supply kit--watercooled turbo only

gauges -boost -oil pressure -oil temp -water temp -EGT

intake piping (mandrel bent)cone filter

gaskets -exhaust manifold -turbo flange-wastegate

vacuum hoses (silicone or rubber) -'T' fittings

clutchflywheel
Modified by IWannaS15 at 12:15 PM 12/10/2004

[Drift Machine]

Okay, well I'm sure his next question will probably be the same as mine, since we're both pretty new to turbo. I understand the concept and function, but maybe not all the parts.

So here goes... When pieceing together a turbo kit, what all would I need to round up? I know I'd have to get these parts:

exhaust manifoldturbo (probably a t3 or t3/t4)maybe an intercooler if I could find one cheapBOVWastegate

I'd have an exhaust shop around here do the pipeing for me. I don't really understand how manual boost controllers work or what waste gates do (vent exhaust, but why would you need to do that?). I also dont know what controls the BOV. I've searched this before, but it seems like the KA-T section is pretty advanced for me, along with other newbs to turbo, and can be kind of intimidating.

Thanks,Mike

Definately get an intercooler they can be had for cheap.

Wastegates make it so you stay at a certain boost level. They contain springs, the spring in my wastegate is a 6 psi spring. So when my turbo hits 6 psi the wastegate opens having exhaust flow out before it can reach the turbo so it can't spool up anymore. So I don't 'overboost' and go higher then 6 psi and reach levels my system wasn't meant to handle. What happens when there isn't a wastegate, or the wastegate fails and doesn't open, is the turbo just keeps on 'spooling'.

I have my BOV hooked up to my FPR line.

I hope I could help, I tried to keep the explanation as simple as possible.

[fiznat]

Good post IWannaS15, that includes pretty much all of the major parts you're going to need, except maybe a clutch and differential. For people just learning about KA-Ts or turbos in general (we should make a sticky about this), check out http://www.howstuffworks.com for info on engines and turbos (especially look at the turbo one, and the ignition spark timing one)... Also it would help a great deal to get and read Corky Bell's book "Maximum Boost: Designing and Installing Turbocharger Systems." There may be better books out there but this is the one it seems like everyone (including myself) has read.

Dont feel intimidated by the KA-T forum! All of us there started out as complete newbs as well-- there's no reason you cant ask simpler questions like this, or read some of the more complicated stuff in an effort to learn more. That's what I did, and I'm sure thats what a lot of other people did. Alot of this sounds more complicated than it is-- once you start putting everything together (either in your mind or on your car ), its not that bad at all.

Good luck!

[Poor_S13_Driver]

Thank you everyone for your replies. All of the information was very useful. Its made me realize a lot of things and rethink my goals for my car and make them a lot more practical. AustinSilvia made a lot of sense and thank everyone for their time and patience -lyons

[mkory]

Okay, so if your wastegate will keep your boost at 6psi, then the BOV is just so you're not boosting through your shifts, right? I always thought that the BOV regulated the amount of pressure.

What is an FPR line?

You guy's have helped a lot, I think I'm definately going to print off Iwannas15's list and start rounding up my parts. I'll probably start posting some more specific threads pertaining to some of the items in that list.

Thanks again, Mike.

Poor_s13_driver... didn't mean to hijack your thread or anything, but I think we're in the same boat here, thanks for bringing it up.

[hannibal]

Wastegate is on the exhaust side of the turbo. The BOV is on the intake side. It allows to boost thru your shifts.Instead of the turbo pumping air toward a closed TB, the BOV gives the air a place to go. A blow off valve just releases this air into the atmosphere, while a bypass valve (often referred to as a BOV too) recycles the vented air back into the intake.

Try to find a good picture of a KA-T and follow the air pathway from air filter into the motor and out the exhaust.

[mkory]

Whats a TB? I get how it works, its just some of the pieces involved that i dont understand their function.

[scruffy63]

the tb is the throttle body its the piece that lets air in the intake manifold.

[AustinSilvia]

okay well there is no need for me to post a list cause it's already been done a million times above, but i wanted to make a quick note. i dont know if anyone's said this yet or not, but here's what my experience has been... piecing it together for a relatively cheap price isn't all that hard... what becomes expensive though are the small things. all little misc. parts will cost $300 easily, so be prepared for that.

also TB stands for throttle body.here's how that $10 manual boost controller works: it is vacuum and spring controlled. see wastegates are also vacuum controlled. at certain boost levels the wastegate opens so the boost doesn't go above the desired level (what the wastegate spring is set at). this is all fine but wastegates tend to creep open (called boost creep) instead of open all at once when the boost rises to the disered level. well a little manual boost controller (mbc) can help eliminate this boost creep because the boost controller is spliced into the vacuum line that controls the wastegate... this way there is no vacuum going to the wastegate until the mbc lets vacuum through, which increases the speed of turbo spool. this is because the wastegate is shut completely and the turbo gets all the exhaust gas until the mbc lets vacuum to the wastegate... then it is the wastegate and boost controllers job to keep the boost constant (once it is at the desired level). is all this making sense? if not just let me know... i think i covered it all pretty much as easily as i could.

[AZhitman]

Great thread - I'm enjoying the education myself!

[mkory]

Okay, so with the MBC, how does the controller know when to allow the wastegate to recieve a vacume? Is there some kind of pressure sensor that the MBC uses?

Also, how does the wastegate know when to open and close? You said that there's a spring, which reacts to a vacume. Would I just install a different spring into the wastegate, with a different amount of tension that would cause the wastegate not to vent as early, and let the turbo make more pressure?

[AustinSilvia]

the mbc is vacuum controlled just like the wastegate. there is a vacuum line that goes to the wastegate to tell it when there is boost or no boost or whatever. the springs are then opened and closed based on vacuum changes in the intake manifold. so basically the mbc is a little spring loaded device that is in between the intake manifold and the wastegate on the vacuum line. it restricts and vacuum going to the wastegate until there is enough to open the mbc spring. then vacuum going to the wastegate can open the wastegate spring. basically it makes sure the wastegate gets all the vacuum at once so that the turbo will spool fast and not creep up to the desired boost level.

this is just how little $10 mbc's work. then when you get to more pricey affairs like digital boost controllers and such they are more accurate. they don't rely on springs. they have pressure sensors that can be adjusted with great accuracy.

your guess as to spring rate and changing springs to change boost levels is correct. you can change the wastegate spring to make it stay closed longer or open earlier or whatever you want. it seems to be easier though, if you want to turn up the boost instead of decrease it, to install a mbc and just leave the wastegate spring alone. then you just have to deal with the little mbc spring instead. they are much easier to deal with, especially if you have an internal wastegate, but also if you have an external wastegate.

note though, as i said earlier... turning up the boost is not as simple as installing a boost controller if you want to do it safely. fuel management must be stepped up with stepping the boost up. if not you will most likely detonate.

you'll probably ask about internal and external wastegates next. well internal gates are inside the exhaust side of the turbo and external gates are not directly attached to the turbo. external gates are by themselves tangible objects. some people like internal some like external, but i don't know if there is a real advantage to either one. i see both types on all kinds of setups, for large and small power applications. proper sizing is important but type is not a big deal i don't think. anyway any more questions just ask.

[mkory]

Great reply, it pretty much answered my wastegate questions...

On another note, say I find a good deal on a turbo. How will I know if the turbo will bolt up to my manifold correctly? Is there a universal size bolt pattern/hole size. (called a flange I think?)

Whats the big deal about mandrel bends? I can see how they would be the most efficient for exhaust and turbo pipeing, but is it really that important?

[Drift Machine]

FPR = Fuel Pressure Regulator

A BOV helps eliminate compressor surge, which is when air slams into a closed TB (Throttle Body) and rushes back the opposite way. Forcing the compressor to start spinning the opposite way of the turbine (doesn't actually make it spin the other way, but it's basically what it's attempting to do). You have two options with a BOV you can either recirculate it or have it be atmospheric. Recirculating means that when the BOV opens and lets air out, it just gets put back into the system. While an atmospheric setup just lets all the air spill out into the engine bay (when you hear a really loud BOV it's most likely an atmospheric one).

Heh, don't worry about all the short hand terms we have. It took me a while to realize what they all mean.

[mkory]

Thanks for unconfusing me on yet another turbo related abbreviation and also explaining compressor surge in a way I can understand.

So backing it up 2 posts... Whats the big deal about mandrel bends. Why are they so important? How will I know if a turbo will match up with my manifold?

Also, don't you have to supply oil to the turbo to cool/lubricate it? I see that IWannaS15 included an oil supply kit in his list, but where does this pull oil from and dump oil out?

Thanks again, everyone, for the great posts, I'm learning a lot.

[BadMojo]

So backing it up 2 posts... Whats the big deal about mandrel bends. Why are they so important? How will I know if a turbo will match up with my manifold?

Also, don't you have to supply oil to the turbo to cool/lubricate it? I see that IWannaS15 included an oil supply kit in his list, but where does this pull oil from and dump oil out?

Mandrel bends, unlike a crush bend, will not decrease the inner diameter of the pipe at the points where it's bent. A crush bent pipe will have crimped bends and won't flow as well. A mandrel bent pipe will be completely smooth and will be the same diameter throughout the pipe.

As for whether your turbo will match up with your manifold, you'll want to buy a manifold that matches your turbo, ie. you've got a T3 turbine you'll need a manifold made for that turbo. Most people here run a T3/TO4E or some kind of straight T3 and most manifolds for the KA will be flanged this way.

There's only one manifold I know of that will let you run a T25, T28 or fancy GT series Garrett turbo and that's the infamous SSAutochrome manifold, as seen on Ebay. General consensus is that the T25 or T28 are too small for the KA, but some folks (AceinHole) have had great results with 'em.

There are also tangential and on-center housings to worry about when choosing a turbo. Also, IIRC some older T3's have 5 bolt housings, which could cause some problems.

Most likely the turbo you will use will just need an oil source and a place for that oil to go, like you said. Some will also have water cooling. Your oil source will be where your stock oil pressure sender is, near your oil filter. You can either T-off of that or get a filter sandwich adapter, which SPL sells. IMO, I think the adapter looks better than a mess of T's and other fittings hanging off the engine block. It will also be less likely to crack compared to brass fittings. Some folks run a restrictor between the block and the turbo, but to be quite honest I'm not sure of the necessity of that or the restrictor size you'd need.

Your oil return line will go to your oil pan. You'll need to weld a bung in to the pan and run a line down there. There are some good threads about where exactly to weld the bung in to the pan. You want a nice straight, easy path for the oil to flow down so you drain properly and don't get oil leaking past the seals in your turbo.

That's my 2¢. I'm still working on designing/piecing together a turbo set-up for my car. Lack of money and the necessity of repairing stuff on my poor old S13 has been holding me back, but at least I've had time to research ALOT. I guess that's one benefit of being poor.

[LaughingBull]

Still learning about turbos myself, but from what I understand for the oil you can either do a seperate tank or you can weld an outlet to your oilpan. If this is right wouldn't the seperate tank be better since the oil would be hotter comin off the oilpan?
Modified by LaughingBull at 12:44 AM 12/12/2004