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87 Nissan 200SX, SR20DE+T, MS1-Extra

Posted: Sun Nov 29, 2009 3:50 pm
by seishuku
This is my first venture into MegaSquirt, so far so good.

I had it running and idling today:

It runs pretty well with the chipped stock ECU already, so no real big reason to go to MS, but I'm doing it for the experience. Though I do like the real time tuning and features, plus being able to do coil on plug later on.

Right now I have a small stub harness:
Just push the tinned wire ends into the stock ECU harness connector, but will probably be wired in once I get it running well.

Timing pretty well translates over from the stock setup, so at least I don't have to worry about that too much.

Here's my car specs:
94 S14 SR20DE, 10:1 compression, NVCS
T25g @ 11PSI
DeatschWerks 450CC injectors
Bosch 023 fuel pump
93 octane pump gas, with water/meth injection
Custom FMIC

Just need to get down and tune the fueling.

Re: 87 Nissan 200SX, SR20DE+T, MS1-Extra

Posted: Tue Dec 01, 2009 4:10 pm
by seishuku
Did some tuning on it today, got it running somewhat nice now.
My laptop battery died before I could get to fixing the accel enrichment, so every time I step on the gas too fast it would buck and pop.

One thing that bugs me though, I can't get it to run with dwell settings. It'll only start and run with a fixed duty cycle.
Anyone know why?

Re: 87 Nissan 200SX, SR20DE+T, MS1-Extra

Posted: Fri Jan 01, 2010 4:05 pm
by Liquid_selva
Hey mate,

Nice work with the car, she runs quite nice except the accel enrichment.

I have a question though as i want to embark with the MSII on my SR20DET and was wondering if you used the standard SR20DE ignition or whether you converted to Coil On Plug/multi coil setup? Just that the only information i have found about the DET's Crank/Cam angle sensor is that it is Optical. was wondering how to go about getting the COP that the DET's have to work. does it simulate the tooth wheel or is it going to cause issues with the MS???

Cheers mate.

Re: 87 Nissan 200SX, SR20DE+T, MS1-Extra

Posted: Sat Jan 02, 2010 8:08 pm
by seishuku
Yeah, it's with the stock DE distributor, but I plan on going with a COP waste type setup in a few weeks/month.

The problem with the original optical disc is that MS can only use the 4 inner windows, so you only get the basic distributor trigger (and can cause kick backs and starter issues). No chance for waste spark/COP there, so you either need to modify the disc for a 2nd trigger.

Here's what I did with my disc:

You can also use an AEM, Autronic, or Mazworx Motec disc, even a DSM 4/1 (COP) or 4/2 (waste) optical disc can be used.
So no special trigger wheel decoder coding is needed, just the basic decoder.

So far I can't seem to find the proper trigger angle for "this cylinder" mode though, at least not with the distributor in place. After I switch to COP, I can move the distributor anywhere I want to get a nice 60 degree trigger angle. So for now, I'm stuck with a 5 degree angle (which could actually be 0 too).

Re: 87 Nissan 200SX, SR20DE+T, MS1-Extra

Posted: Sun Jan 03, 2010 4:33 pm
by seishuku
I also fixed the issue with no dwell control.
It would seem that with a fixed duty cycle, there's just enough of a pull-up through the D14 LED and it's 330ohm resistor to trigger the ignitor in the distributor, but then using dwell it doesn't work (higher DC = more current maybe?)
Also I can now get "this cylinder" mode too, which shouldn't have been related, but who knows. It works with an 80 degree trigger angle. :lol:

So, with a 390ohm resistor to 5volt pull-up added to the spark output, spark inverted set to no, and dwell set, it now works PERFECT.
With the 2nd trigger added, it helped with the kick backs, but I still had to crank and crank until it would keep running. Now, it's not even 2 seconds on the starter and it's fired up!

Things just get better and better! :D

Now to get some more ignitors and put in the COP setup.

And I've attached my latest MSQ, for anyone interested. I may also be switching to the hi-res code soon, but still debating that.

Re: 87 Nissan 200SX, SR20DE+T, MS1-Extra

Posted: Thu Feb 04, 2010 10:51 am
by seishuku
Building up my coil harness:

Coil drivers, ST BU941P ignition power darlington transistor, I've used them before to replace OEM transistors and had great results. Pretty cheap too.

2-valve modular Ford coils.


Just need to finish soldering the transistors up on the harness, install heat sink, and wire it up to the MS.

Re: 87 Nissan 200SX, SR20DE+T, MS1-Extra

Posted: Fri Mar 12, 2010 9:26 pm
by Liquid_selva
Looks like she's coming along quite nicely mate...

Are you running your modified distributor? or are you going by another route? like possibly the DET Crank/Cam angle sensor? or using a missing tooth setup?

Re: 87 Nissan 200SX, SR20DE+T, MS1-Extra

Posted: Fri Aug 06, 2010 1:30 pm
by seishuku
Haven't posted an update in awhile, I did finish the coil harness:

But I screwed up and cooked all four coil drivers, so I have to order some new ones, but haven't got around to it yet. The reason being, is that for some reason #1 cylinder decided to seize the upper ring, so I had to fix that (which took way longer than I wanted).
I have some pics of that, here:
But anyway, it's back together with slightly lower compression pistons (9.5:1) and running very well.

For the coil packs, I could use the trigger wheel that I rigged up, but I was having some timing drift issues with that (which may have lead to the ring seizure), but we recently got a new WaterJet at work, so I made this:
It's a 24+1 CAS disc, which is perfect for MegaSquirt. I still get a real small amount of timing drift (drifts retard by maybe .5 degree per 1000RPM), but it's MUCH better than a few other variations I tried.

I'm also working on making an oil adapter block for my SR, much like some of the others you can find online. I had the material, and with the water jet, why not?

Re: 87 Nissan 200SX, SR20DE+T, MS1-Extra

Posted: Mon Sep 06, 2010 8:09 am
by seishuku
Been doing some more tuning since the rebuild, I forgot to mention in the last post that I also have VCT working. Kicks in at 1500RPM (just off high idle), and turns back off at peak torque, about 5500RPM. Makes a huge difference in torque.

With VCT on, VE fueling requirements raise about 30%, so obviously it's making a boat load more torque across the board! I love it.

I've also removed the water injection system for now, with a new plan to relocate the injector, and add 3 more for a much more efficient direct port injection.
In the mean time, I've decided that the wimpy T25G just doesn't have the flow to really justify having the water spray, though with the 10:1 compression it was a nice safe guard.
It will be going back on if I put anything bigger on, like a GT2871 or some T3/T4 @ 10PSI. :D
But I may have some forged 8.5:1 pistons by then too, so it might not be needed ever. I don't know.

I've attached my latest tune, I've got AE and warmup pretty well tuned in, and found ASE to be useless right now. I'll have to wait until winter weather to hit, to get it really tuned in. Otherwise it's making some decent power, it's tuned up to 12PSI, I haven't ran it to 1BAR yet, but it should be good to that.
Timing needs some dyno work, I know there is some flat spots in the torque curve, but I don't have the money to get some dyno time, so just keeping it out of knock is the goal. Which I've dialed the upper load and RPM timing way back, almost to 0.

Re: 87 Nissan 200SX, SR20DE+T, MS1-Extra

Posted: Wed Sep 08, 2010 6:09 pm
by seishuku
More tuning, redid the timing map, based on Ben Fenner's another ECU SR20DE, tweaked it due to my intake cam phasing.
He really did an awesome job on it, throttle response is awesome, free revs really quick compared to what I use to have.