My 1990 300zx Twin Turbo build by megaDan

14 minute(s) of a 731 minute read

Been a while since I've posted.

I think I've gotten nearly everything sorted out with the car, except for the tune. The car runs good, but there is a funky lean spike right around 2k rpms that I think is killing my torque output.

Yesterday a couple friends and I drove down to Canton for a dyno day benefit. It was a chassis dyno (more info when I get the graphs).

Buddy with a SN95 cobra put down 250hp with just pullies.

284whp and 270 torque for my Z with stock wastegate pressure (12psi). Kinda disappointed. I think a lot of it comes down to the tune. (ashspec chip currently) I really wish I could have been ready for the Specialty Z tune day in Cincinnati. I should get the graphs tomorrow, but now I need to learn how to use my Nistune ECU and software.

DYNO:

To be fair, I found out on the ride home that I popped off two vacuum caps and a fuel line. I hope that was the reason for the crappy showing.

6/13/2012

I thought I had a RMS leak, turns out I never retightened the oil pan bolts after installing it with RTV orange initially. To get to all of the bolts I had to remove the transmission brackets on the driver's side and loosen the bracket on the passenger's side. Since then I haven't seen a drop of oil from the back of the motor.

I installed a Greddy Profec B Spec 2 boost controller that I found on the forum last week now that my motor is broken in. It feels good to get up to 15 psi again!

I got an auto NA nistune ecu for a steal a while back, and 91ser came down from Chicagoland again to help adjust the tune. I've been running an Ash tune set up for my 755cc top feed injectors, but after installing the sport 500 turbos and AMS exhaust manifolds I've had a lean spot at part throttle that I wanted to get rid of. After doing a fair amount of reading we learned how to copy the maps from my TT ecu onto my netbook, and transfered them onto the nistune ECU. We went for a drive but were unable to see the effects of our changes. I think we were running into issues with the gear map, so the gear and knock maps were disabled and things really took off from there. 

We pulled some fuel out at the top end (shot for 11.5-12.0) and added some down low (shooting for 14.7 low load) and the car runs SOOO much better. We filled up after about 1/2 tank of highway driving, 1/4 tank of accelleration runs, and 1/4 tank of cruising. 19.996 mpg!!!! Typically I've only seen 20 on 100% highway tanks. I can't wait to see what this current tank gets me. I'm going to need to modify some other rich spots down low, and I want to try and lean out very low load areas some more to improve fuel economy (after doing some more reading on how to tune). I just can't believe how much of an improvement we saw with only a few hours spent in the car. 

6/27/2012

MPG Update:

Last weekend I gave the girlfriend a VERY brief overview of how to use nistune, but with her help dialed in the tune on the freeway in 5th from 55-75. AFR at part throttle is almost dead on 14.6-14.8. After filling up on that tank I got 21.9mpg. 75% freeway/country roads, 10% commuting 3.5 miles and back to work a few days, and 15% with the old tune. Looking better!

I'd like to know how some people are getting 25+ on the freeway. My goal is 22-23mpg on the highway so its not too painful on the wallet for long trips. 

Check me out on fuelly.com for MPG updates. 

Also took delivery of a second MAF, Selin Translator, and oil sandwich plate this weekend. The plan is to take a long weekend over 4th of July to see Cake at Summerfest, help my buddy finish up the V8 install in his slicktop, and install a DOOLZ (dual intake) on my Z. Should be good for quicker throttle response and about 20-30HP. Oil sandwich plate is for oil temp/pressure gages whenever I get a carPC installed. Hopefully this winters project. 

7/12/2012

First off, I know I need more photos. Just took a 1500 mile road trip and only got one crappy cell phone pic of the Z. Probably because it was dirty most of the time

Second. 22.9mpg for the road trip. Averaged 22.5, saw best tank of 22.9. I am quite pleased with this, I'm making more power and getting better fuel economy than the last trip I took 2 years ago. I'd still love to break the 23mpg mark. Those numbers are from sitting at 75-80 much of the time with a few spirited runs in between. Wisconsin has some great roads to drive.

Third! Picked up a Z1 Doolz from my friend in Chicago on my way back. Installed it yesterday in about 30 minutes. (I'll snag pics at lunch) The full setup is, Z1 doolz, silicone couplers, AIP maf (wanted OEM but the guy I bought it didn't state that it was aftermarket) and dual JWT popchargers (only one has a flower pot mod at the moment), and selin translator set to ADD. I've got a few observations.

1: Driveability is MUCH better. Previously in 5th gear below 1800rpms or so the car would bog down and shudder if i gave it throttle. I really had to be in 4th until 40+mph to drive the car smoothly. Not the case any more, 5th gear is usable down to almost 35mph. This should help fuel economy pretty significantly as most of the roads around here are 35 (boo).

2: This is completely subjective, but the car seems to drive much smoother. This is both good and bad.

3: At 15psi power doesn't seem to come on in as much of a RUSH as it did before. This makes the car feel slower. I've only driven with this setup for about an hour, so these observations may change. I did a log last night with nistune and saw TP load hit a new high of 73 (previous TPload max was about 63) so it seems to be making more power. It just doesn't feel that way. I REALLY need to completely redo my tune, but I'm not sure I have the skills for that. I've got a rescaled map created, but I'm afraid to use it. My current TP load scale maxes out at about 44. I'm monitoring everything very closely while driving, but something tells me its not a good idea to have the ECU interpolate that far beyond the chart.

4: Despite having my ballasts mounted at the outer edges of the engine bay and the selin right in the middle, I still get LOTS of interference. When I tried to pull away at the gas station I killed it because it was running so poorly. It didn't occur to me until the second try that the problem I was seeing was because of the HID's. When I turned the headlights off the car ran great. I need to read up on how people are correcting this. 

7/16/2012

We were 5 miles from home after 4 hours and 150 miles of driving all day Saturday when the car died at a fairly busy intersection. Barely managed to get it through the intersection and into a driveway.

Could not connect to the ECU with consult

Code 55 - All OK

Aux fan running with key in accessory position

Car would barely idle (VERY rich) and would die with any throttle.

CEL was on.

If I let the car sit for 3 minutes, the fan would not turn on at the turn of the key, but as soon as I gave it throttle it would start with the above symptoms again.

Called AAA and was home within 30 minutes. I had planned on swapping ECU's in the morning on Sunday because everything I read suggested a bad EPROM or bad ECU (Current ECU has a nistune board). Some others suggested bad MAF, which almost makes sense because I'm running a dual maf setup (1 oem 1 AIP) with a selin translator but that doesn't explain why I couldn't connect to the ECU. 

Sunday I started up the car and drove around the development with no problems. ??? Now I have to drive around wondering when this will happen again.

I've got a spare ECU and spare single intake ready to swap over in the car in case this happens again. Has anyone else encountered this problem before? Is it possible to have this caused by a bad maf when running the selin? I would think that if one maf is bad (and set to ADD) it would be reading to LITTLE airflow and be running lean. Has anyone ever had a bad nistune board? 

8/6/2012

Well its happened twice more now. ECU dies after long drives. Swapping to my chipped TT ecu will allow the car to run fine indefinitely. If I drop the nistune ECU back in the next day it'll work fine again. A brief visual inspection of the ecu innards didn't reveal any problems.

Not really sure what route to take. I'm assuming/hoping its the ECU and not the nistune board that is bad. I guess my next option is to find a cheap working NA ecu and swap the nistune board over. 

8/27/2012

I got in on the initial offering of the Royalty Performance 13" rear brake group buy, and they were delivered about two weeks ago. However my golf was still up on jackstands with my troublesome steering rack replacement so I couldn't install them.

I finally was able to tackle this job on Friday with the help of my girlfriend before I took her out to dinner :-) In total, it probably took us an hour to install these, wheels off to wheels on (including the time it took to learn how to adjust the parking brake). Very VERY simple install. I did have some problems with the heat shield rubbing against the backside of the rotor which I had to spend 5 minutes adjusting on Saturday, but nothing major. Unfortunately I haven't had a chance to really test them with any simulated panic stops yet.

I definitely like the look though. It makes the fronts look smaller, but I like having 13" all around. They look much better under my 18" wheels.

Crappy photo on the way into work:

I've got this winter's projects pretty much lined up.

I've got a 2.5" intercooler piping kit waiting to install, still need to purchase larger intercoolers with 2.5" inlets. I'll have my OEM throttle bodies bored out and the plenum matched to account for the larger piping. Dyno tests have proven almost +100 low end tq with this upgrade alone. Combined with my slightly larger than stock turbos, lag should be almost nonexistent with a monster torque curve. 

The seats (and probably interior) will get recovered in charcoal leather, along with a new shift boot and ebrake to go with the red stitched shift knob my girlfriend got me for Christmas last year.

I plan on moving away from my triple 52mm gauge setup and switching to a double din bezel with a car PC running datascan/nistune. This way I can still monitor oil pressure/temperature/everything else with the sandwich adapter I'll be installing and I won't have to clutter the interior with more gauges. 

Finally, I'll be cleaning up the engine bay and powder coating the plenum and balance tube and valve covers to get rid of the cruddy old aluminum look I've got going on. I really should have done this last winter, but I was too focused on getting it to run after my first ever engine build.

That will pretty much cover me for performance upgrades. The suspension is still pretty firm, I don't plan on altering that until my bushings start to go. Its a toss-up between that and paint as my next major modification, probably 2+ years down the road. I'm hoping that this winters round of upgrades are all I will need and I can drive it for a few seasons without sinking any more money into it. I've been planning on all of these for the last year, and I don't have anything else I need to do, and I struggle to find upgrades I want to do. 

10/6/2012

I've been trying to find a local dyno day for a while now, with no luck. So I finally got around to calling Bigshot Dyno down in Stow. I live in a city of 51k people and 100k within 5 miles, and I have to drive almost an hour to the closest dyno. Boo.

Anywho, I did my first dyno this spring with a chip tune and 12psi and put down a measly 290ish hp. Since then I got Nistune and using ZERO tuning experience dialed in the chip tune on the street and turned up the boost to 15psi. I also installed a doolz intake and selin translator.

I've got a set of Ash Massives V3 and 2.5" intake piping on the way for install this winter and I wanted to get another baseline prior to that mod, and a comparison from where I was at this spring.

Runs on a DynoJet reporting STD Horsepower.

Run 1 broke up a little so we didn't log it.

Runs 2 and 3 were nearly identical, within 1hp and 1tq at 15psi.

Run 4 I turned the boost controller back down to 12psi to get a comparison to this spring (plus the dual intake and tune)

15psi- 351whp and 367tq!!!!!!

12psi-331whp and 339tq!!

VERY pleased with these results. My goal of 450whp should be attainable with 17psi and breather mods! 

The standard Z32 ECU has a main board, and a daughterboard that lies parallel about .75" away on the other side of the casing. The two are connected with a 1" wide ribbon cable. Nistune replaces the standard aftermarket EPROM chip with yet another daughterboard in between the two, right where the ribbon cable is. 

I dissected the ECU looking for loose or bad solder joints, but everything looked good, the only thing that was suspicious was the ribbon cable squished between the 3 ECU boards, and the ribbon cable was up against the backside of the Nistune board, which had many exposed pointed leads. I put some insulating material in these locations and haven't had a hiccup since.

10/12/2012

Ashspec Massives V3 intercoolers delivered. Over twice the size of my current intercoolers, and these have a 2.5" inlet/outlet to mate up with my waiting 2.5" intercooler piping.

Won't get to install them until late winter/early spring.