T3? T3/T4? What?!?

[Jammin1911]

Heh, Ok this is gonna sound dumb, but I'm knew. &nbsp;I dont know crapall about turbos and I'm just wondering what T3, T3/T4, and if there is any more, and what they mean. &nbsp;I figure its size or somethin, i guess it could only really be the size of the turbo or the type? &nbsp;I dunno, I'm just guessin. <img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/smile.gif" border="0" valign="absmiddle" alt=':)'>

[Kreator]

ok. get this (http://www.amazon.com/exec/obidos/ASIN/0837601606/qid%3D1034201277/sr%3D11-1/ref%3Dsr%5F11%5F1/102-5945164-6788900)

Yeah, they mean sizes. a turbo consists of two parts. the compressor outlet and the turbine outlet. The T3 has both compressor and turbine of equal size. On t3/t4 the turbine outlet is bigger. Everything else u need you will find in the book. There are numerous turbo sizes. But t3 and t3/t4 are the best fit sizes for our cars for daily driving.

[Jammin1911]

Hmm, sweet!
thanks bud.

[Jeff240sx]

I don't think that people need to buy "The Book" if they have a simple question on what the hell we're talking about.
T25 is the smallest, and is stock on sr20det motors. &nbsp;On the s15 sr20det, the newest block available, there is a t28. &nbsp;A little bigger. &nbsp;Then most other cars (300zx, T-bird, ect) have t3 turbos. &nbsp;A t3/4 is a hybrid, with a fast spooling exhaust (t3) housing and a big-boost making compressor (t4) housing. &nbsp;Then it goes from there, T4, T66, T77, T88, T100. &nbsp;T4 is the biggest a 240sx can handle for most people.
Those are all Turbonetics / Garrett turbos.
Then Mitsubishi makes their own turbos, with separate size designations. &nbsp;16g (small) 18g (larger) ect.
If you have any other questions... pm or post.
-Jeff

[Jammin1911]

Ah sweet, thanks Jeff. &nbsp;Awesome explanation.

Ok, I understand that no problem.

Another more complicated (i think) thing I'm trying to grasp about turbos is the boost, and how it is affected with different sizes of turbos.

If that question doesnt make sense, here is a more specific question:

Ok, using the sizes you just gave me as reference.

Would a T25 (small) turbo @ 8psi give MORE, LESS or the SAME amount of performance increase than say, a T4 (big).

I dont really understand how the psi affects the boost amount (or hp increase, whatever)

At first I assumed just that the bigger the turbo the more psi it could push, like a T25 could maybe only push like 6psi or something. &nbsp;But thats not true, right?

[Kreator]

Oh sorry messed em up. Yeah, t3 is the exhaust side, t4 is the compressor. Doesn't really make sense otherwise....

Jeff, i think that the eclipse came with a t25 turbo. Also the guy said he wanted to get a turbo later on, so i thought he really might need "The Book".

after reading your post above: psi for each turbo is different based on it's size. That means that a t25 at 7 psi provides less flow than a t3 at 7 psi, therefore less hp. They provide the same air pressure, but the smaller turbo will be pushing less air. That's why a t25 on a ka would probably be worthless.

[adey]

While I can't answer your (last) question, what I can say is that you have much reading to do. Asking these types of questions is undoubtedly a good thing, but people here get tired of seeing it and explaining it. I suggest taking a night off and reading up on some of the archives you can find at Freshalloy (http://www.freshalloy.com/). They are an *excellent* nissan forum, and arguably (or rather, I should say quite unarguably) one of the best sources for nissan technical information online.
The moderators there (esp. asad) really, *really* know their stuff. Check it out.

Basically, though, a bigger turbo boosting 6psi will flow more air (and hence give more power) than a smaller turbo boosting at 6psi... simply because it's bigger. However, there's the all-too-familiar problem of turbo lag, where bigger turbos suffer.

[Jammin1911]

Hmm, cool. I'll check it out. Thanks!

Edit:
5 Minutes Later
~~~~~~~~~~~
Still Loading freshalloy.com!! (slow or broken? )

[Kreator]

<!--QuoteBegin--adey+Oct. 09 2002,7<img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/wow.gif" border="0" valign="absmiddle" alt=':0'></span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (adey @ Oct. 09 2002,7<img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/wow.gif" border="0" valign="absmiddle" alt=':0'>9)</td></tr><tr><td id="QUOTE">While I can't answer your (last) question, what I can say is that you have much reading to do. Asking these types of questions is undoubtedly a good thing, but people here get tired of seeing it and explaining it. I suggest taking a night off and reading up on some of the archives you can find at Freshalloy (http://www.freshalloy.com/). They are an *excellent* nissan forum, and arguably (or rather, I should say quite unarguably) one of the best sources for nissan technical information online.
The moderators there (esp. asad) really, *really* know their stuff. Check it out.

Basically, though, a bigger turbo boosting 6psi will flow more air (and hence give more power) than a smaller turbo boosting at 6psi... simply because it's bigger. However, there's the all-too-familiar problem of turbo lag, where bigger turbos suffer.</td></tr></table><span id='postcolor'>
yeah go read up stuff on freshalloy. And if you are serious about turboing yer car (not the sr swap) than GET THAT BOOK. Honestly, i learned more from that book after 3 hours of reading than after spending 4 months reading up stuff from the net.

Oh and on the psi limit - yeah you are right. But it's not even close to 6psi. It's much more. Basicly at some point the turbo starts overspooling. E.G spooling so fast that it might break. You don't want that to happen. On the other hand, bigger turbo will still be in it's normal range pushing the same amount of air as the overspooling smaller turbo.

[veil_side_]

Two words: &nbsp;MMmaaaxxxxx BBooooosssttt!!!!

no seriously dude, I didn't know crap either. &nbsp;Yeah I still have some questions (but don't we all). &nbsp;But it cleared up alot of stuff. &nbsp;Still not done reading it though.

[Jammin1911]

Alright alright, I'll get this book and read it, not right now tho. &nbsp;<img src="http://www.zilvia.net/f/iB_html/non-cgi/emoticons/smile.gif" border="0" valign="absmiddle" alt=':)'> &nbsp; I still have 5 or 6 months till I get my car and need to worry too much about it.

Thanks for all of the help you guys have given me so far though, its very appreciated.

[Jeff240sx]

One of the main factors on deciding which turbo to get based on flow rate is... the max boost you will run. &nbsp;a T25 will spool up extremely fast, but won't provide the boost you want. &nbsp;Also, you know that whole 10* drop in intake temp equals 1% more power? &nbsp;Smaller turbos always run hotter, because they have to spin like hell to compress the same ammt of air as a large one. &nbsp;But with the large one, boost won't hit for a long time. &nbsp;I don't get full boost untill 3600rpm. &nbsp;That's a T3/4e. &nbsp;I've talked to a couple people with a T4 and they said their boost doesn't come untill 4k rpm. &nbsp;But their turbo will make more boost and run cooler.
Anyway. &nbsp;Sizing up a turbo is based on your goals. &nbsp;If you want 4-6psi (stock setups, with fuel pressure regulator), which is the cheapest setup... go with a t28 or t3. &nbsp;That will put you where you want, with the fastest spool. &nbsp;Don't get a T77 or T100 Thumper to make 6psi max. &nbsp;You'll never spool that sucker untill 6k-6,5krpms. &nbsp;If you even can spool one.
-Jeff

[luke91]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote </td></tr><tr><td id="QUOTE">Then most other cars (300zx, T-bird, ect) have t3 turbos</td></tr></table><span id='postcolor'>

300zx TT's have T25's.

[sykikchimp]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (luke91 @ Oct. 10 2002,2:04)</td></tr><tr><td id="QUOTE"></span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote </td></tr><tr><td id="QUOTE">Then most other cars (300zx, T-bird, ect) have t3 turbos</td></tr></table><span id='postcolor'>

300zx TT's have T25's.</td></tr></table><span id='postcolor'>
Z31's had t3's.. some years even came water cooled. &nbsp;Not sure about later models, but I think you are right. &nbsp;I believe the Z31's T3 came with a .63 AR ehaust housing, which is excellent for the KA.

This is actually the turbo I wanted to use for my car when I had Junkyard KA-T plans...

[Jeff240sx]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (luke91 @ Oct. 10 2002,3:04)</td></tr><tr><td id="QUOTE"></span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote </td></tr><tr><td id="QUOTE">Then most other cars (300zx, T-bird, ect) have t3 turbos</td></tr></table><span id='postcolor'>

300zx TT's have T25's.</td></tr></table><span id='postcolor'>
Z31. &nbsp;
-Jeff

[Evil S14]

t3, t3/t4 and t4 is more of a classification, sort of a broader generalization

t-25s ans t28s are t3's
t-60+ is &nbsp;a t/4

or so i hear