1985 300zx - Tuning question

[TheToast]

What's up guys... I'll start my introducing myself. My name's Nick, I'm 19, live in Connecticut and bought a 300zx give or take 5 months ago. This is my first post on these boards, and as it happens I've got a fairly critical question that needs answering... Here's some background first.

What I have - 1985 Nissan 300zx 5 spd420cc injectors, 60 trim turbo (unsure of what type), 3" exhaust w/ no cat, MSD ignition, a boost controller that isn't hooked up, and some other miscelanious modifications - I bought it a few months ago as-is. It had a chip on the computer, but the chip fried, and I had to replace it. [only at 7~8lbs of boost on the turbo right now]

So now I'm running all those performance modifications on a stock 1984 computer... if I put my foot down, I get lots of smoke out the back, and a gassy smell constantly, as you would expect. If you hold your hand in front of the exhaust, your hand literally gets wet with gas.

The original computer had a Jim Wolf Tech chip on it, so I contacted them first... They told me that they no longer supported older computers, and that I would have to upgrade to an 88/89 turbo computer, swap out to a cobra MAF (I JUST put a new MAF in, I don't really wanna replace it) and then buy a chip for THAT... They insisted that was the only option.I contacted Stillen Tuning as well, they said almost exactly the same thing, but they said I could probably get an AFC to do the job as well...

Down to the questions! First... Would there be a big difference performance wise, if I buy an AFC and have it tuned, compared to swapping computers, MAF's and chipping it?

Second - I'm not exactly rolling in cash, so the ~$1,200 Cobra MAF + Computer + Chip isn't too appealing. Lets say there's not a life changing difference in performance, would you guys have any compatible AFC's to reccomend? I would like to get this sorted out ASAP.

Since I now have a car with obvious performance mods, I figure it'd be good to learn what the f*** I'm doing. I appreciate the help - I'm a complete novice in car tuning, so I could definitely use it!

[evildky]

your stock ecu can't handle those large 420cc injectors, with such low boost you coudl simply put the stock injectors in to match the ecu, the z31 uses a maf system so the turbo size doesn't matter

I'm no fan of the fuel controllers, they are limited and expensive, if oyu watch the forums and ebay you'll see the late model bits come up form time to time (I just got a complete 87.5 turbo parts car for $500) if you want to make big power and don't wan to swap to the later style injection you could do megasquirt, thats what I'm running on my Z31 at present, with wideband you cna put together a system for around $600 and we're talking full stand alone, granted it's a whole other ball game and has a steep learning curve and isn't well documented for the Z31 but mine made 315 whp on megasquirt

[TheToast]

So that pretty much just replaces my current ECU system? Definitely gonna have to do the research on it...

Also, what are the specs on your 315 whp z31?

I'm definitely going to up my boost, although I hear mixed reviews - What would you recommend for optimal psi, without blowing my car up? 14, 15 or so?
Modified by TheToast at 10:35 PM 2/11/2009

[evildky]

depends on if you have an intercooler, with no intercooler, 10 psi max, if you have an intercooler but are running stock ecu and stock injectors I'd guess aroudn 15-16 psi you'd max otu the fuel, with an intercooler, large injectors, and proper engine managment 20-25 psi

megasquirt isn't for everyone, but given your situation, you either need to repair your ecu, upgrade to the later style ecu with propper chip to handle the larger injectors, run a stand alone, like megasquirt, or put the stock injectors back in and be happy wtih less power

here is my Z31http://forums.nicoclub.com/zerothread?id=388953

[TheToast]

The original chip is legitimately broken... Oh yeah, I forgot to mention both Jim Wolf and Stillen no longer produce chips at ALL for older model Z's. I was reading up on Megasquirt last night, I do wanna get through the FAQ on it to see if it's the right solution for me.

Looks complicated, but not so much that I wouldn't wanna try it. Now I just gotta decide... ~600 dollars plus lots of labor on my part, or a nice and simple 1200-1500 for a bunch of new parts.

Your Z is pretty beast... If I figure out megasquirt and get that going in mine, you think I could be putting out similar hp/torque to yours?

[evildky]

the turbo that put downt hose numbers was a hybrid, which was supposedly a to4b compressor side, which I don't doubt as it was larger than stock yet smaller than my to4e, and it came form a car with the 420cc injectors and cobra maf jwt ecu (I didn't get the ecu or maf form the guy) but that was intercooled at 25 psi, also that was before i added wideband and was kinda a blind tune I modified from the maps I was running on my 240Z and I ultimately broke 5 pistons, that car now runs liek a champ but hasn't been back on a dyno, the to4e should put down better numbers but looks like it'll be getting a stock t3 and electronic's form my 87 parts car and sold off, once I get the Z32 out of the way

[AZ-ZBum]

Nistune:http://www.z31performance.com/...t=968

[evildky]

I thought nistune required the later syle ecu?

[TheToast]

I've decided that I'm going to tune my car with an AFC as a stopgap measure... Just until I can get the money together for a permanent solution. Who can recommend a good AFC to use, that would be compatible with my ZX? Also, I need some way of monitoring how rich/lean my engine is running.

Thanks

[evildky]

....wideband....

[Z31toZ32]

In the meantime maybe you could wire up a spark plu to the exhaust pipe with an on off switch int eh cabin so you could shoot flames out the back.

[Gregmatic]

Your best bet would be to look into Nistune or even Megasquirt. Your attempt with an AFC will yield more problems than anything else, wasting time and money (an extra $200 will get you a Nistune'd ECU). In the meanwhile, revert back to stock injectors and enjoy the way a properly tuned (stock) turbo Z runs. Perhaps take this opportunity to focus on supporting mods such as brakes, suspension, intercooler, etc. I recall seeing that car somewhere, I forget if it was on a forum or on Ebay. Wheels look good! Also cool to see another Z31 guy in CT. There are a few of us here, keep your eyes and ears open on other forums and you'll see one from time to time. Also look into CTZCC.com , there are several good meets a year.

[Z31Guy]

Hey, I have an 87' 300ZX turbo, and just picked up the MS-II kit. It is ready to go in and i am trying to find some people with a similar set up that maybe i can pull a map from.

87' 300ZX Turbo:3" intake/exhaust2.5" piping/24x3x13" intercooler255 Walbro FPMS-II ECUWideband O2Spec stage 3 ClutchAluminum Flywheel

currently stock injectors, but have some nice 420cc's that i would like to use (main reason for the map is that i have no skill at tuning as of yet).

If you have/know someone who is willing to help a bro out, i would really love the helping hand!

Thanks for playing guys, Cody J.
Modified by Z31Guy at 4:59 PM 10/21/2009

[evildky]

I can try sending you my msq file, but there are lots of other variables, and the tuning is pretty simple if you get a wideband, the current megatune build is awesone, you just log the run, load the msg file, overlay the log and it tells you what corrections are needed and even will make them for you, repet the process several times in different driving conditions and it just keeps getting better and more complete

[Z31Guy]

Wait? WHAT???

so you just drive the car (assumeing you get it started) lol and it will show you what the system reads where/ what optimal reads would be, you take those optimal reads, and overlay to the EMS... lather rinse repeat?

That sounds almost too good to be true!

i have a wideband O2 and gauge, are you talking about the $199.00 cable that connects it to the MS-II system when you say to get an O2?

If that is how i make it that easy, i will pay to play.

Thanks tons bro! Z31Guy

[Bernard]

I have a later -88 or 89 ecu and can send it chipped for your injectors for 250.00 plus shipping. Bernard

[evildky]

the zemulator also works on earleir ecu's but they lack the wideband support and tunign software

[Z31Guy]

hey, i was just wondering if anyone has done an install on a z31? (80's 300zx) I cant find the fuel pump relay or "main relay"...

any help is great!

thanks fellas.

[AZ-ZBum]

hey, i was just wondering if anyone has done an install on a z31? (80's 300zx) I cant find the fuel pump relay or "main relay"...

any help is great!

thanks fellas.

Fuel pump relay is in the passenger door B-Pillar. Down low. Can sometimes get to it by removing the vent there.

[AlexM23]

depends on if you have an intercooler, with no intercooler, 10 psi max, if you have an intercooler but are running stock ecu and stock injectors I'd guess aroudn 15-16 psi you'd max otu the fuel, with an intercooler, large injectors, and proper engine managment 20-25 psi

megasquirt isn't for everyone, but given your situation, you either need to repair your ecu, upgrade to the later style ecu with propper chip to handle the larger injectors, run a stand alone, like megasquirt, or put the stock injectors back in and be happy wtih less power

here is my Z31http://forums.nicoclub.com/zerothread?id=388953

. What all did you use to get you car tune I been looking for some many things can't find anything it will be great if you gave me a list of all the things you used

[AlexM23]

I need to tune my car and I was told that safc wasn't the way to go. Does anyone know what I can use and everything I need to tune it?

[evildky]

Zombie thread.

Safc is a piggy back fuel controller that manipulates what the computer sees and basically tricks it into adjusting the fuel mixture, I'm still not a fan of these and they offer no timing control.

I used a magasquirt with a gm iat, stock cts, s13 tps, on die map sensor and ditched the mas. Tuning software for megasquirt is constantly evolving, tuner studios was the tuner to have when last i tuned, I did use it in conjunction with an innovative wideband. Megasquirt setup gets you close enough to get the car running, tuning takes time, a wideband and preferrable a dyno. Honestly I'd recommend Nistune or similar romulator, it's a lot less complicated to add and while not as flexible as the megasquirt it works with all your stock stuff and allows for timing and fuel tuning, basic tuning is actually fairly simple, If I built another Z31 it's what i'd do.

[AlexM23]

Zombie thread.

Safc is a piggy back fuel controller that manipulates what the computer sees and basically tricks it into adjusting the fuel mixture, I'm still not a fan of these and they offer no timing control.

I used a magasquirt with a gm iat, stock cts, s13 tps, on die map sensor and ditched the mas. Tuning software for megasquirt is constantly evolving, tuner studios was the tuner to have when last i tuned, I did use it in conjunction with an innovative wideband. Megasquirt setup gets you close enough to get the car running, tuning takes time, a wideband and preferrable a dyno. Honestly I'd recommend Nistune or similar romulator, it's a lot less complicated to add and while not as flexible as the megasquirt it works with all your stock stuff and allows for timing and fuel tuning, basic tuning is actually fairly simple, If I built another Z31 it's what i'd do.

. So use

magasquirt with a gm iat
Stock CTS
S13 tps on die map sensor
Tuner studios
Innovative wideband

Is that all I would need?

[evildky]

yup, thats about it.

[AlexM23]

yup, thats about it.

Where can I get all of that? I you can can you provide me links pleas?

[evildky]

diyautotune.com and a junkyard