Afshin

I just took a break from the packing for the big move (to NJ first and then likely to Maryland) and saw this post. Thanks for the kind words Len. I'm definitely very happy with how this car has turned out as it has exceeded my expectations. I have spent the last year mostly on fine tuning of the car after having made all the major upgrades over the previous years, and it has paid off nicely (the car is actually running faster with less boost than before). I certainly enjoyed the Z31 set up as it made for a significant improvement and was cheap and easy to do. However, as the project continued I felt it was time to move up to a fully programmable fuel and ignition system. I almost went with a megasquirt set up, but was so busy and decided to go with the very reliable SDS system. I absolutely love it (however full data-logging would have been nice). Tuning fuel and ignition on the fly is an absolute blast Guy, while improvement in handling from new bushings is a “no brainerâ€, as you likely know most people have it on their to do list but don't get to it. I keep trying to make the point that it is crucial to having a nice handling car and that the difference is more than most expect. I also think that it makes a bigger difference in the ZX than the Z because of the more compressible rear semi-trainling control arm design. So Yasin, I say drive your Z over to New Josey and we will put in your nice race prepped head and jeffP downpipe over the weekend then we turn up the boost and go for a friendly race

There should be no difference.

Beautiful craftsmanship!!! I'm sure you will be enjoying the ride for some time to come.

I just sent you a PM.

ANother thing just came to mind, I'm not sure of this, but it may also be that the signal will be too weak to pick up from the ecu if there is no signal drain from the ignitor. For example with the SDS system which uses he MSD box as the signal amplification module, the voltmeter/autometer duty signal funtion will not read a pulse unless the ingition pulse wire fron the SDS ecu is actually connected to the msd box. In other words it may be that checking the signal straight from the ecu without the ignition circuit being complete (ignitor functioning and connected...) may have too weak a signal for even the duty cycle function on autometers to pick it up.

How are you checking for the pulsed signal from the ecu to the ignitor? A voltmeter will usually not pick up a short ignition pulse and will read no signal when there is indeed one. If your voltmeter has a duty cycle function or if you have an oscilloscope.. then you can check for the pulse (it's hardly ever the ecu).

I used to have the old g-tech and it was fun, but prone to error if not leveled properly and so a little bit of a pain to use.... I then got the g-tech pro and it think it is great. Another magazine maybe grassroot motorsports (i'm not sure) had done a review as well and found them to be accurate. I find the results very consistent. Also, the HP and torque measure are not that reliable compare to dyno results in a non-moving car with no aerodynamic factors, but they are GREAT for comparing all modification made to your car both for HP/torque curves and max. values. I'm sure you will have a lot of fun using it.

It's funny, so many people dump out good oil at 3000 miles but then use a cheap Fram filter. Spend the money on a good filter (I get the K&N), good oil and then make full use of it. Not that I have the nerve to keep the oil for 8-10K miles.

Hey SleeperZ, nice to see you back on the forum

Thanks for nothing man, now I have no choice but to add a cam to my never ending list of goodies BTW on the subjective side, any difference in idle quality, cruising, engine smoothness....

The spare should fit in the rear. So, if you get a front flat and it doesn't fix with fix a flat or air compressor than put the spare on the rear and put the 17" good rear tire on the front

I don't know why your ignition won't shut off, but the automatic and manual ecu have the same pin configurations, so the answer is somewhere else. Also the wires related to this are the same for the 280 and 300zx, so the swap, if done correctly should not affect the turning on and off function. Check out the diagrams.... if I remember correctly, pin 6 is the power source coming from the EFI relay that turn the unit on and off and pin 114 is the constant main power source.

Dave, aka dacelooper has some nice diagrams and pictures of the ecu plugs... that are very helpful. He was nice enough to poste a link on the second page of this thread, somehow people keep missing it. I would advise that anyone attempting this read all the posts carefully as important info was added from the time I wrote the first post. John, you will flood and foul the plugs with 370cc injectors unless you have the ecu reprogrammed. Adjusting the screw on th MAF won't cut it (you would need a much much larger air bypass than the small hole on the MAF). Put back the original injectors for now. ALso, since the VCM will no longer work, you will need to adjust the throttle body stop screw to adjust the idle up (the throttle body plate needs to be further opened for proper idle with the Z31 set up). Regarding pin 108/16, that is to turn the fuel pump relay on and off, if you have a different set up to turn the pump or relay on and off than you don't need it.

I'm with wheelman on this one and would not worry yet. clean the plugs, clean out all the oil...I have had the same thing happen on different plugs at different times and it never happened again. After all the oil is on the outside of the engine and if the plug was not falling off, how would the oil pass thru the thread and just pool there when 1000psi of peak combustion pressure can't leak thru? At least that's my thinking on it. Am I missing something in the failing rings theory?

Ok everyone, I think that responses to post should relate to the case at hand. We are not discussing hypothetical scenario, someone posed a real question, the answers should follow suite. So for this set up, the comment “retarded timing improves spool up†while true in a vacuum, could unintentionally be misleading. I don’t think anyone would argue that the problem here could be advanced timing. As I explained earlier, if there is a timing issue in this case, it is because of excessive retardation. Also while Scottie is almost always right and undoubtedly knows more than I do about turbo systems, I will have to respectfully disagree with him. Increase boost does not always result in more power over advanced timing. That statement is only true when timing is not excessively retarded such as max advance of 18 degree under boost and when the turbo is still in an efficient range of operation. As boost increases so does heat, when a turbo is being pushed beyond it’s limit where the efficiency drops (not too hard in a non-intercooled Z with a T3) power gain becomes marginal (and hence can be offset by timing power gains….), furthermore since so much heat is generated from the inefficiency of the turbo at higher boost, the timing has to be so retarded, that spark happens so late that combustion occurs when the piston is already too far on it’s way down, resulting in low combustion pressure and decrease power. And sticking with a stock l28et, this scenario can easily happen. Since in my line of work, references are a requirement and given that I’m pretending to work now, I will do the same: Hugh MacInnes in his book: Turbochargers on page 68 gives an example of a VW engine, he said that as they advanced ignition too far, the exhaust cooled and boost and hp dropped, which is an example of too much advance not being good (again not the case in this post) but also said as total advance dropped below 26, the car gained boost BUT power decreased because of the retarded timing. Graham Bell in forced induction performance tuning, page 72 claims “more boost and less spark advance OFTEN spell less hp†Also based on personal experience, but without dyno quantification, I have felt the l28et running stronger at 12 psi than 14 psi with the amount of retardation needed to avoid detonation, this was with 91 octane and an intercooler. Sorry about the long post, but I’m both bored and enjoying the topic at hand

What Yo2001 is referring to is that with retarded ignition, exhaust temperatures go up which can enhance turbo spool up and at times reduce lag. However, that is certainly an overgeneralization and often not true, especially in the case of the l28et. Retarded timing can cause very low off boost power and sluggish engine response which not only will decrease power but also increase the time needed for the engine to built RPMs and therefore increase lag. The sluggish response and low off boost power also make the power build up very nonlinear, which makes the car feel very “laggyâ€. So getting back to the topic of the post, retarded timing will decrease power, engine responsiveness, and increase the lag. Just set the timing at 18 then drive it and then try it at 22 and tell me which one builds power faster. Retarded timing can also affect power to the point that when tuning cars at times decreasing boost a few psi to allow for a little more advance timing increases horsepower, despite less boost. BTW, what is your base timing set at? If you are running 12psi without an intercooler, my guess is that your timing is quite retarded to avoid detonation, if so try droping the boost by 2 psi and advance timing by 2 degree and take it for a test drive and see if it helps.

Ah! I just noticed that you said a 79zx. I have no idea if the cv's bolt up to your 79 hub or not. I put the 300zx lsd into my zx, but it is a 83 turbo which came with the cv's. You can probably take a look under your car and compare/measure the cv to hub flange and see if it is the same or double check with Ross as Pete suggested.

I will repeat what Scottie said, if you have excessive lag, it's likely NOT from the turbo. It is always best to fix any problem before going to the next step. Are the ignition related component all up to date? any exhaust manifold leaks, timing (too retarded will increase lag)... T3/T4's are nice, but obviously will increase lag a little, but certainly not to much (depending on which unit) in a properly running set up. Also 3" intercooler pipe is a little overkill, 2.5" is generally good for 400hp. So if you have not bought the pipes, I would advise you use a smaller diameter pipe. You could also consider on of the garett GT ball bearing turbo's, supposed to have better design and less lag. Ask the turbo shop about them.

It bolts right in and the fined cover fits as well. The mounting bracket is different, but you just bolt the bracket from the 280zx straight onto the 300zx lsd unit. The CV's slip in with no modification. The hardest part is to take the main driveshaft mounting flange off the 300zx unit and bolt the 280zx one in. It is a direct swap. However taking the flange bolt off can be a pain. You may want to take the diffs to a shop so they can use an impact gun to get the nut off. Other than that enjoy, it's so worth it.

Wow! and that the original mini, which is much smaller than the current model. That't going to be a blast to drive and keep on the road.

I saw part of the Newfoundland Targa race on speed vision, it looks like an incredible event. 7 days of driving thru beautiful roads closed to the public with every kind of imaginable car (mostly old models) in the race. My friend and I are hoping to run it in a few years. Weither we can really make it happen, remains to be seen. Meanwhile i'm just enjoying the thought of it.

http://news.bbc.co.uk/2/hi/health/4559055.stm Now this is progress. Turbocharging rules supreme, no V8's here Boy would I enjoy tuning this patient.

My understanding is that as you increase exhaust efficiency, you decrease backpressure and improve turbine spool up. Now since spool up is improved and the turbine spins faster, you need to bleed more exhaust thru the wastgate to keep the turbine from spooling faster and increasing boost. In other words the turbine spools faster for the same amount of wastegate opening, which then causes the compressor to spool faster and you get more boost. So the wastegate is still opening the same amount as before the new exhaust install, but now the turbine and hence compressor spins faster and more boost is created. Remember, the wastegate opens partially, how much it needs to open for a given boost depends on the turbo unit, flow efficiency, exhaust efficiency, downpipe....You improve efficiency and then wastegate needs to divert more exhaust from the turbine to maintain same boost.

It looks like the RRFPR is turning out pretty reasonable for your set up. Running in the 11-12's after peak torque as opposed to continuing in the 10-11 range broadens the power band on the top end while maintaining a reasonable safety margin, as far as I know. It will be interesting to see how your afr's turn out once you upgrade your downpipe and exhaust system. It may be that it will run a little rich from before peak torque, which won't be optimal for power, but likely would still work reasonably.

Great info, thanks