What turbo should i get?

[scottyMIz]

I'm planning on getting one for my zt this winter which one should i get?I want to run about 20-25psi.I'm going to get some head work done and a new cam.Any suggestions?

[Kevin Shasteen]

Scotty,

 

Picking a turbo isnt like choosing a gear shift knob and its even more involved than choosing a camshaft; and we all know what kind of questions arise when one poses the question "What Camshaft Should I Use"! I think you know that & this is why you've probably asked your question.

 

My suggestion to you would be to research turbocharging yourself & learn to read turbo maps. This way you wont have to ask which turbo is best for your needs because you will "KNOW" which turbo is correct for your needs.

 

There are to many variables involved to simply "suggest" a turbo. You have pressure & temperature differentials that have to be understood & then you have the metering devices that control those pressure/temp differentials which also need to be understood.

 

Also, do a internet search on turbo's & read their tech info...anything offered as free advise on their sites is always helpful.

 

If you're planning on going 20-25psi boost-then it is imperative you understand what you are doing.

 

Sorry there isnt an easier answer for you but you yourself need to read a few books & then cruise the tech aids on some internet sites...then you'll be able to answer your own question. Good luck & always have fun.

 

Kevin,

(Yea,Still an Inliner)

[Drax240z]

There is a very good article in this months Sports Compact Car about turbo sizing, etc. They've recently started "suck, squish, bang, blow" and there have been some really good fundemental tech articles written for that section.

[Guest Anonymous]

With a title like that are you sure you got the right magazine and you wanted to tell us about it?

 

,

Lone

[Scottie-GNZ]

Scotty,

 

assuming you are going to get a new or rebuilt turbo, talk to the turbo manufacturer and let them spec one out for your intended use. Personally, if your goal is mid to hi-11s, spend the cam money on something else. You can go a long way with the stock cam and heads. Just as or more important is the programmable system, traction, I/C, traction, DP & exhaust and TRACTION. Oh, and in case I missed it, you have to address traction. Pointless in spending money for a cam to get you .3 when you are losing .5 because the car will not hook.

 

PLEASE, tell me you are budgeting for brakes and suspension.

[scottyMIz]

Thanks for the info guys.Is that the new sport compact car mag?Do you have that one issue drax?If so i'd buy it off of you we don't have sport compact car mags up here.

Scottie if you say so you'd definately know about the cam thing.I'll get some other things instead like brakes and good springs and struts.I plan to lower the car as soon as the exhaust is moved so i can lower it.I don't know how to read maps and all that tech stuff i get lost just hearing it.If i had hands on then i learn much faster.I'm going for the wheels next scottie hopefully the traction thing will be close to solved.If not a whole lot better than it is now.I'll probably have to get drag radials.I'm learning as much as i can on my own but books only help me so much.I have mamimum boost and that's suppose to be the idiot guide(according to some people) and i'm still stumped on some things.I just ask that you guys don't get really impatient with me.I don't have a whole lot of time on the net either my old lady gets pissed when i'm on here too long.(5min is too ong for her)But i learn something new everyday especially on here.

[74_5.0L_Z]

This site has a java applet that suggests which turbo and trim to use based on engine size, max rpm, number of turbos, etc...

Ray Hall Turbocharging.

 

I am just beginning to explore the world of supercharging, so I can't vouch for the validity of the answers the applet provides.

[Kevin Shasteen]

quote:

---

Originally posted by scottyMiz:

..,I just ask that you guys don't get really impatient with me..,

---

 

Scotty,

 

I hope no one on this site ever gets short w/anyone for any reason...we all have to approach auto mod's at our own level & you , like the rest of us, should ask as many questions as you need.

 

If you have Maximum Boost then that is a good book; however, I wouldnt call it the "Book for Dummies"; it is a very [complete] book in its approach on turbo's & done in a way that if you understand [airflow] to begin with...then you can understand turbo's.

 

Atleast that is how it worked for me. I initially purchased Hugh MacInnes book over a year ago:

 

...after continually reading Scottie's progress w/his GN/Trubo car I thought I would further my understanding on turbo's...

 

however, it didnt even make a dent on me as my metal block as at the time I had no real understanding of airflow. When I say Airflow I'm talking about 1)Density of the Air/Fuel, 2)Speed of the Air/Flow & 3)Compression of the Air/fuel as well as 4)combustion of the Air/Fuel.

 

Once I finally had a major breakthru, mentally speaking, on airflow-then all other dominoes just began falling like a house of cards. This happened just recently, after a two year R&D on my own, literally reading everything I could & seriously attempting to understand the dynamics of an engine; and believe me there were countless nights I fell asleep w/the book on my eyes & my ceiling room light on only to awake at three in the morning to realize I had fallen asleep (countless times this happened); until I finally began understanding. It was at that time I decided to re-read Hugh MacInnes book & everything made sense...I still had to read somethings two/three times-but I understood it.

 

I've recently purchased Maximum Boost by Corky Bell & have found it much more complete than Hugh MacInnes book (more current) & am still reading it; but I think for you to fully understand it, I mean really understand it, you have to have a [basic] understanding in Airflow: Density, Speed, Compression...as this is what the Turbo effects, as does any modification to an engine.

 

The trick to auto modifications is understanding the [how the airflow is effected] when the modification is made...if that made sense(?).

 

Dont fret...keep reading, keep striving to understand even when the mental block seems like unimpentrable-be persistant & the mental house of cards will fall. When they fall, as it did for me, it was like someone opened a door & I walked thru; no longer was I on the outside looking in but now on the inside looking out. Pretty cool; I'm still humbled that I actually understand airflow now. It really is like someone flipped on a light switch.

 

If I can do it then anyone can do it. So keep your questions coming-but try to understand airflow first; then graduate in incremental levels.

 

Sorry for the long post; just thought a pep talk was in order as I've been there/done that..., in the sense of not knowing something auto/perf-wise and realize how it can be frustrating at times.

 

Kevin,

(Yea,Still an Inliner)

[scottyMIz]

Thanx kevin,I can understand some of it just when he starts taking math to calculate stuff then i get lost.I'm much faster at picking things up with me seeing it not reading it.It's just harder for me to relate the info to common sense.I'm not thru the book yet and before the year is over i'll probably read it another time.I ask the questions like what turbo and all that cuz most guys have gone thru it and can have some insite on the turbos.I can see that it's all what i want that decides the turbo now but before the post i didn't know that you can get a turbo for certain spacifics(sp?)Thanks for the site 5.0 i'll check it out.I just didn't want all the guys to give up answering my questions.Get sick of me asking maybe the same question and i didn't realize they where the same kinda questions.I'm relieved to know that you guys will keep helping as long as i don't get stupid and do dumb stuff against your advice.That's why i got the new injectors coming i took timz's advice and upgraded the fuel system so no holes where burned in the pistons.I try to remember everything you guys say to me but some things slip by.If it's about a certain question then i remeber really well.I'm just like everyone else when they have so much going on it their life and trying to get time and mental free time for other things is hard.Anyway time to quit rambling.I'll check out airflow more now that i know what to look for first.

[Scottie-GNZ]

Scotty,

 

if any responses appear to be "crisp" , it is because people are trying to guide you away for doing something destructive. The majority of turbo "failures" is the result of mis or no understanding of the basic principles.

 

Speaking of airflow, here is one that folks are not aware of but I hope sinks in when dealing with forced induction. For every bar (14+psi) of boost, a turbo engine is capable of ingesting twice its rated volume. In other words, a 2.8L turbo engine is capable of forcing 5.6L of volume in its cylinders. Since the cylinder volume did not expand, then it is obvious that the volume is compressed. Now, add to that the compression of a 4-stroke engine and ignite it and that is a massive explosion which explains the ability of a small displacement turbo engine to make such massive torque/power. Think about that and now imagine the actual compression ratio . That is why reducing heat and making sure the turbo engine under high boost has the fuel it needs is so critical.

[scottyMIz]

That made alot of sense thanks.You say it's capable of 5.6L at one bar so if you went higher the amount of ingested volume would be higher right?I'm just trying to see if i understood you completely.I think the only thing i've done that wasn't right was run high boost without enough fuel which is going to change really soon.Does anyone know what the O2 senso is suppose to read when it's running right?I'm going to hook up a volt meter to see if it's rich or lean for now til i get an a/f meter.