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

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

Post by seishuku »

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Latest WOT graph... DC and AFRs are much better now.

It would seem that a combination of low fuel level and pressure set to 70PSI instead of 60PSI were the cause of my problems, though I was still maxing out my 450CC injectors. At least now at the 93% DC it's a 9:1 AFR, so I can pull that back into normal AFRs (12-11:1) and have a safe DC.
seishuku
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Posts: 33
Joined: Sat Nov 21, 2009 2:05 pm
Location: Wisconsin

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

Post by seishuku »

Some more tuning work.
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Much better now and safe.
I haven't seen any MAT over 120 deg F yet either, so the intercooler is doing it's job (it's about 95 out today).

I've attached my latest MSQ, for those interested.
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seishuku
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Re: 87 Nissan 200SX, SR20DE+T, MS1-Extra

Post by seishuku »

Thanks MegaSquirt, you made me break an axle!
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Last edited by seishuku on Tue Sep 13, 2011 2:09 pm, edited 1 time in total.
kholman
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Re: 87 Nissan 200SX, SR20DE+T, MS1-Extra

Post by kholman »

seishuku wrote:Thanks MegaSquirt, you made me brake an axle!
Time for an upgrade.
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seishuku
MegaSquirt Newbie
Posts: 33
Joined: Sat Nov 21, 2009 2:05 pm
Location: Wisconsin

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

Post by seishuku »

If it were only that easy... Parts aren't easy to find to begin with, at least around here. lol

I got a reman'd shaft on it's way, we'll see how long that one will last (or the other OE), worst case I have to get some custom stronger axles made up.

Never thought I'd ever break an axle with a T25, I'd hate to see what I might break with something bigger.
seishuku
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Posts: 33
Joined: Sat Nov 21, 2009 2:05 pm
Location: Wisconsin

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

Post by seishuku »

Decided to ditch using a VR sensor for the crank wheel, and bought a new hall effect sensor that DIYAutoTune came out with.
It's a really nice sensor, no VR conditioner to deal with, just a nice clean square wave signal... And I didn't have to change any wiring really, just pulled the lead from the OEM CAS connector and changed a few MegaSquirt settings.

However, even with the nice clean signal the hall puts out, I still had to run the sensor through an amp, apparently it doesn't sink enough current to drive the 2.2 pcb 'squirt.

http://www.youtube.com/watch?v=leJmlag2Ciw

Rock solid timing, no real timing drift to speak of, but I was having a little issue with it getting RPM spikes above 4000 RPM...
Seems my alternator was causing a lot of noise, which I should have thought of... That's what I get for powering the sensor with 12volt I guess.

Image
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It's running real smooth now, I do need a new alternator though, this one is on it's last legs... Slow to recover, putting out a little too much voltage, current seems weak. It's still working, keeping the battery charged, but it's gotta go.
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maik21
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Re: 87 Nissan 200SX, SR20DE+T, MS1-Extra

Post by maik21 »

hello. your work is amazing. i try to find some info like this and never did until 1 month ago.

sr20de+t + megasquirt is hard to find.

can you post your last results about "CurrentTune.msq"? is it work with methanol injection?

thank you very much.
seishuku
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Posts: 33
Joined: Sat Nov 21, 2009 2:05 pm
Location: Wisconsin

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

Post by seishuku »

Sure.
No, since the rebuild, I've been running with 9.5:1 compression pistons, so I haven't felt the need for the water/meth injection.

It's making a lot of power, the 450CC injectors I've been using at 60PSI (making them 528CC) are still being maxed out (running about 85 to 90% duty cycle), all on a T25.

Not sure how much power exactly though, I still have yet to put it on a dyno.
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maik21
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Re: 87 Nissan 200SX, SR20DE+T, MS1-Extra

Post by maik21 »

did you run 15psi all time without problems? im very afraid of tuning my friends car without a knock sensor. his setup is a 9.5:1 cr , t28 no-ballbearing, 520cc sti injectors and methanol injection.

i think i will not have problems with tuning idle, cruise speed and fuel. but spark is my concern.

can you tellme something about a rule of thumb about -2° for every pound of boost?
seishuku
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Posts: 33
Joined: Sat Nov 21, 2009 2:05 pm
Location: Wisconsin

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

Post by seishuku »

My base timing map is based off Ben Fenner's SR20DE dyno tune, so it's well tuned, then reduced timing by .75 degrees per 1psi.
2 degrees would be far too much retard, and would drop too much torque. I try to keep spark advance at least in the double digits, no less than 10 degrees.

The T25 doesn't seem to mind running 15PSI daily, but it just doesn't last. Puts too much pressure on the thrust bearing, though it doesn't help that my T25 was well used when I got it.

In real world situations, I wouldn't go much over 11PSI and keep shifts around 5800RPM... There just isn't any power at higher revs with that small of a compressor/turbine, even on a T28 I wouldn't bother with much higher than 6500RPM.

You may want to think about larger injectors as well, I have 450CC injectors that I run at 60PSI, which bumps them to 528CC and even then they're running 85% duty cycle. (7200RPM, 10PSI, 11.3:1 AFR)
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