SleeperZ

Does this adapter, or the weld-on type require any CV shaft shortening? Is there an issue with either of these adapters binding up the CV shafts, which I hear are long compared to the stock shafts?

I've always wondered what the current ratings for those stupid fusible links are. I've seen posts regarding this go unanswered, so here is what I've found. I tested a red one and a black one. The red ones will go up in smoke at 30A. I got a black one to carry 60A and it was getting toasty, but didn't open up. I didn't test a green one. Since I will be replacing all the links under my hood with a main fuse block from an '87 Mazda (5 circuits - an 80A, 3 30A and a 40A), I will replace the black link with an 80A fuse, the red ones with 30A fuses, and the green with a 40 fuse. Hope this helps!

Ack! You aren't going to ground the black/white wire!?!? That is the power to the coil from the ignition switch, and you'll just blow the fusible link. Excellent you've got the fuel pump going, you are almost there!

Nope, you'll see no spark whatsoever. The y/w wire is very low current, it's just a signal - it is so weak it can't drive the coil, that's what the transistor does - it amplifies the signal to a current to drive the coil. Even the primary current in the coil won't jump a spark, as it is still just 12V. You can test for a spark only from the plug wires or the main coil wire to the distributor. You could attach a test light from the coil minus (-) to the chassis and the y/w wire to chassis to see if your ECU is putting out the spark signals. Good luck.

My 300zx ECU gets warm to the touch with the ignition on, I'm not sure about the 280zxt ECU. I wish I could supply you a drawing - it would be worth your while to dig up the comprehensive Chiltons manual on Z's and ZX's - mine covers '75 though '89, and has all the wiring diagrams. The power to the ignition is the b/w wire connected to the + of the coil. The - of the coil connects via a short wire to the transistor. The transistor completes the current path to the chassis. The transistor (and subsequently the coil) is switched by the y/w wire from the ECU. Regards,

The black/white connects to the + of the coil (positive). The - of the coil connects to the transistor, the other side of the transistor connects to the chassis (ground). I'm at work without the diagram, so I'll get you the color of the fuel pump wire tonight. Not sure about your 5 wire connector near the battery...does it plug into the EFI relay?

OK, I dug out my old photocopy of the 280ZX turbo wiring diagram. The transistor emitter is grounded throught the chassis, so you don't have to sweat that one. The positive to the coil comes from the ignition switch on a black wire with a white stripe. This same wire powers the relay coil for the EFI relay. The negative side of the coil connects directly to the transistor collector with a short blue wire. The trigger for the whole mess goes through a yellow wire with a white stripe through an 8 pin connector directly to pin 5 on the ECU. Hope this helps.

Hehe, it's not a secret on this forum, or ZCAR.COM. What a funny thing to say. It's true the R200 4.11:1 diff is rare, but it comes on '85 and '86 200SX turbo cars.

Yes, I'm pretty sure it was printed in "Maximum Boost". It seems to me that whatever you do to install the studs in the block, it shouldn't affect how you torque the nuts over the cylinder head -- that determines the pressure on the head and the gasket.

Well, maybe I didn't explain what I meant well enough. The theory behind the studs is you preload the threads in the block with the stud (bottom it out, and torque it). Then when you torque the nut down, you relieve the stress on the block threads, and you have a net cancellation of forces in the block that will hold the cylinder head down more reliably. Actually, I've heard (not stating a fact), the retention of the stud, or any threaded fastener, is supported only by three threads, and adding any more does not increase the retention force.

i am following this thread with some interest, as eventually i want to get some of these head studs. what is not making sense to me is the recommendation of hand-tightening the studs into the block. if you hand-tighten, then you are not realizing the benefits of the studs, which is a large preload partially neutralized by a nut on the top end, reducing stress on the block threads. any further ideas?

You should still get fuel pump action when you turn the key from off to on, unless your EFI relay is not activating. With a bad transistor, you just would not get spark - the fuel and computer still operate.

Errr...maybe I need to learn to read first. I thought I read you were just putting the computer in with the n/a harness...doh! When I put mine into my 1st gen, I studied the heck out of the two cars wiring diagrams, and made the appropriate connections. As I recall, I wired the fuel pump signal from the ECU directly to the relay, which was already wired into the rest of the car. I used the trubo EFI relay, and simply wired the old power from the fusible link to it. You may need the turbo coil and trigger -- I don't know if the n/a coil has the external transistor trigger, and you do need that. Good luck, and sorry I jumped the gun.

I think your best bet is to get the turbo wiring harness. If I'm not mistaken, the connectors on the turbo ECU are different than the n/a.

I don't know of many people that actually try to measure the backpressure. Try disconnecting the exhaust and run it that way, then you will know if it's the backpressure, or the stock turbo is just running out of steam. James: You are probably right about the stock turbo being capable of 17 psi, so it's probably exhaust restriction limiting his boost. However, I don't believe a stock turbo is capable of putting out 20+ psi you are claiming at any useful flow rate, even a T3 super 60. Just by looking at the T3 flow maps, 20+ psi is very high up the chart, any flow you manage to get out would be so hot the air would be useless. The T3 compressor cannot flow enough air on the L28 past about 3000-3500 RPM without overspinning the turbo (150,000 RPM) at 22 psi let alone 26 psi. You are caught between the surge limit and the maximum turbine speed.

Actually, I ran the stock ECU for a while, and recently switched to a Z31 ('87ZXT) ECU. I've finally got all the bugs out of it, but I still can't run the knock sensor - the ECU stores a sensor error. I'm thinking it may be the noisy inline 6 motor? As soon as I can get a cheap (used) 300zx knock sensor, I will try again. By trade, I am an electrical engineer, and I have some knowledge of machine code. That's why I went with the 300zx computer, as I intend to dis-assemble the code and reprogram it, just like Jim Wolf does, only cheaper. By no means am I the end-all to turbo knowledge, as I have yet to install an intercooler in my Z and run high boost, however I am well studied, and I think I have a reasonable practical knowledge on the subject having troubleshot my system going on 4 years now.

Also, let me add that if you are boosting to 14 psi, definitely retard the initial timing back from the 20 BTDC. If you have a good intercooler, you may be able to advance it back, once you feel there is no danger of detonation. You will know if your pop-off is limiting your boost, as it will hiss or flutter when you hit its limit. You may also have too much exhaust restriction if you are peaking boost early, and it's dropping off at higher RPMs -- either from a stock exhaust and turbo or plugged cat.

I don't believe the stock computer adjusts timing for boost, because there is no boost sensor to measure boost. However, I don't know how the computers are programmed, and it may be possible to deduce boost in software given the air temperature and airflow measurements. However, I have a somewhat low expectation of these cheap and dirty ECUs and I doubt the stock computer at stock boost levels even needs to retard timing. My 0.02, FWIW.

Try Ray Hall Turbocharging. There is some good useful information there. http://www.turbofast.com.au/ Also, I highly recommend "Maximum Boost" by Corky Bell.

I apologize, but I am only understanding part of this. I just want to add my 0.02, then I'll go away. IMO, the best place to reference the wastegate is the compressor housing -- the nipple poking out the side of the compressor snail. When you reference the point where the boost is generated, you have the least lag and the best control over the wastegate, and consequently the most stable boost level. Also, Scottie GNZ's method of raising boost by shortening the rod SHOULD only work to a point (I know it's working well for you ), but by removing travel from the actuator, there will be a point where the actuator cannot open the wastegate all the way as the internal spring will go solid. My idea, and what I will implement soon, is just to add spring tension to the wastegate externally, which will not limit the travel. If your boost is uncontrolled at higher power levels and RPMs, this could be the problem. Once again, I know I didn't directly address the problem, but I hope the input is well taken.

I don't know the upper limit, where the stock manifold makes a serious impact on performance, but I saw a L28T yesterday rip low 12's on the stock manifold. I think that is close to 400 horsies in a 240Z. Of course, he's running the stock cam as well, but a 3" exhaust. If I were to try to make 500 hp, I'd go with a tubular exhaust manifold, but not for 400.

FWIW, the dropout on a 7812 is 2.5V, so you could regulate 12V from 14.5 or higher, which is close to charging voltage. http://www.national.com/ds/LM/LM341.pdf I'm not sure you will get much more accuracy out of the gauges, especially since automotive regulators seem fairly good - it seems the only time I see voltage drop much is with lights and wipers on. You can fine tune the sensors with a small resistor wired in series, but I would think the gauges are intended to be used with a supply voltage of 14V-15V.

Hey TimZ (sorry to barge in on your post, Evan) what exactly is that "oil trap"? Is that what it is called, or did you just discover that's what it did and it's meant for another purpose? Where do you get such a thing - I am needing to get something like that for my breather, as I still have a PCV and a stock computer thing going. Thanks,

That is a sweet looking IC -- you will have much less pressure drop on that one I can tell. I thought you were considering a liquid/air intercooler...or was that 240Z turbo?

I've been stalking the Supra forums, and they have some fair to middlin' insights about the EGT thing, and this is what makes sense to me. The temperature drop across the turbo is substantial (this is what powers the turbine, so this is expected). So the obvious place for the sensor is where you are talking about -- under the manifold before the turbo. This is the location I am going to place my EGT, soon as I get my gauge. The Supra folks say you should not exceed 900C before the turbo, and depending where on the downpipe you put your probe, expect to read 650C-700C when your exhaust temperature before the turbo is at 900C. So FWIW, I would not want the probe after the turbo because who knows what sort of a temperature drop you have across the turbo? I'd rather know what the exhaust temperature is, not what it might be given the downpipe temp. (of course if you have a crappy probe, you have a problem, if it breaks off -- byebye turbine).