Preformance on New s12

Hey guys. Im new to this fourm. I just bought a 1987 200sx Turbo and i wanna put some more horses under the hood. i have been looking at turbos lately and wouldnt mind upgrading. if i do what need to be upgraded and replaced. i really wanna make this thing go and if you have any tips or tricks then they would be greatly appreciated. thankd alot

Brad

you should start by fitting an intercooler before anything else.

the t25 off a s13 fits on the s12 pretty easy and can run a bar boost at lower charge temps than the t2 could.

it should be on 6-7 psi as standard. with those mods you should be able to run 14.5psi (1 bar) this will have greatly increased you hp figure.

you should start by fitting an intercooler before anything else.

the t25 off a s13 fits on the s12 pretty easy and can run a bar boost at lower charge temps than the t2 could.

it should be on 6-7 psi as standard. with those mods you should be able to run 14.5psi (1 bar) this will have greatly increased you hp figure.

What he said but you will need a bigger fuel pump and possibly some cooler plugs (not expensive plugs just one size smaller NGKs) if you want to run 14 psi.

If you don't baseline yor car first (stock O2 and/or EGT readings), and then monitor changes as you turn up the boost, you're asking for trouble past 12psi.

We really need the old forum back up for the old "Tuning Ethics" post in What the Hell Is That?

well ya baselineing is key.... but i can say that running 18psi on the t25 off the sr20det motor, can be had using the stock fuel system.. i have done its and i was still rich all the time. i dont recommend running so high all the time.... i ran 18psi when i had a bit of 111 left in the tank.. 14psi would be good for over all power around town

That's a bit confusing, Bart. Bart means a T25 originally on an SR20DET, but now on his CA18ET in place of the stock T2. Bart is still using the CA18ET engine found in North American and UK models (SOHC turbo).

I think Johnnyfive also runs 14psi on a T25 with no fuel upgrades. I run 14psi on a 60trim t3 with no fuel upgrades. I run 93 octane. I don't even want to think about the duty cycle on my injectors though.

Bart means a T25 originally on an SR20DET (SOHC turbo)
duz the SR20DET in the us have a T25?? there all T28`s in the UK

If you don't baseline yor car first (stock O2 and/or EGT readings), and then monitor changes as you turn up the boost, you're asking for trouble past 12psi.

You're going to have trouble finding a wideband that will read richer than 10:1, I know the Innovate LM1 unit I used recently only read to 10:1. Your stock fuel mixture is around this value or richer (except when cruising or idling on the o2 sensor of course, and if you are cruising or idling, then who cares about the AFR?). It's been proven by many people that past 12 psi on a T25 isn't a problem (and most of these people do not have fuel tuning capabilities), so I wouldn't worry about any trouble unless there is something else that is already damaged and just waiting to break.

*EDIT* I think all the folks with a t25 are intercooled however, but I don't think it would be a problem if they weren't.

duz the SR20DET in the us have a T25?? there all T28`s in the UK

There are no US spec SR20DETs unfortunately. All US SR20DETs came from another country.

duz the SR20DET in the us have a T25?? there all T28`s in the UK

:laugh:

I wish we GOT SR20DET's in the US! We only got the SR20DE FWD, but IIRC, the early SR20DET's had T25's (the redtops?), then the blacktops had T28's. But I could be wrong on this as I'm definetly no SR expert...

s13 redtop sr-t25
s14 blacktop sr-t28
s15 blacktop sr-t28

So what about a CA18DET T25? With DET 370cc injectors? What should that be good to? I've been running it at ~9psi at the moment for a while, and its CRAZY rich (nice black PLOOM when I go WOT, I get full boost performance at 1/2 throttle, if I push and further to the floor it starts smoking black, gets louder, but doesn't really go, no more additional boost). Just curious how far I can crank it with the T25, 370cc injectors, and the AFC for tuning (I've got it out like 40% I think at the top, and I'm STILL blowing black soot... lol!)

Just curious how far I can crank it with the T25, 370cc injectors, and the AFC for tuning (I've got it out like 40% I think at the top, and I'm STILL blowing black soot... lol!)

As bart said, he ran 18psi. Since the stock fuel supply can handle that, there is no reason to think your uprated injectors wouldn't be able to. As far as I know, none of the Ca18et guys on the board have scattered their insides yet. Just keep an eye on your knock sensor. You will probably want to put a wideband on it while you raise the boost just to make sure you don't have some sort of fuel issue, plus, you could probably pick up 10-20hp by getting the AFR closer to 12.5:1. That's free horsepower, and better mileage under WOT to boot.

Yeah I have a wideband... left that out sorry... I run like 10-11 at the moment... haven't tried leaning it out further, bu tlike i said, I'm having ground/spark issues at the moment... think its my coils/wires/plugs/etc and need to swap all that stuff for higher perfromance ones... I just bought the cheapest last time around just to get it running (like $30 out of pocket for wires & plugs). I was just farting around with it then... =) Need to get the high dollar items now... NGK, Iridium, MSD, etc... =)

time to get that Magnecor set I posted about. They have them for CA18ET.

duz the SR20DET in the us have a T25?? there all T28`s in the UK
Like bart said I don't know the trims or ARs off the top of my head but they are easy to look up if you want that kind of info. This is the info and prices i have picked up from being a resident on a few knowlegable local forums.

CA18DET (S13) T25 of some kind, fairly small makes around 130rwkw at most. Worth throwing away or selling for $100 :P

SR20DET (S13, sometimes called redtop but it can have a black rocker cover) T25G bit bigger than CA turbo, makes 150rwkw easily can make around 160 or so when pushed. Worth around $250-350au

SR20DET (S14 VVT motor) T28, bigger and nicer than the T25G but usually ignored for the S15 turbo. Worth around $500-600au

SR20DET (S15 VVT motor) T28, can be either a BB or plain bearing core but it's hard to tell which is which, oz spec cars seem to always be plain bearing wheras jap ones are mostly bb. Very nice turbo similar to a GT2510. Capable of 200rwkw or up to 220 or so when pushed. Worth around $800-$900au for a jap spec or $600-700 for an oz i've seen.

There is also the GTiR turbo which is a T28 and has a bigger exhaust housing than the S14 or S15 turbos, makes good power but is more laggy, i think it's capable of over 200rwkw as well. Likewise the SR20VET from the jap spec X-Trail is apparently quite nice to, apparently very similar to the S15 turbo.

here are some info on the turbos including a/r's

http://www.boostcruising.com/silvia/turbos.asp

Not a bad source of info, don't take it for gospel though i'm pretty sure Zoom made a few small mistakes in there but overall it's good info.