z-ya

The stock injectors are low impedance, and require either the PWM settings to be correct, or series current limiting resistors. If neither is done, the injector drivers can overheat, and thermally shut down. Look at duty cycle, if it hit 100%, and you don't have resistors or the PWM set right, the injectors will stop firing when thermal overload is reached. No fuel -> no run -> no RPM in Megatune. Is it a turbo application with stock turbo injectors? If so, you are more than likely hitting 100% duty cycle, especially with the stock fuel pressure regulator. Add two more ground wires (18-20 AWG) in the DB37 cable. Also add two more ground wires from the relay board to the chassis or battery. Remember, the MS provides the ground for the injectors, fuel pump relay, and fan relay. A single 20 AWG +12V wire is fine, but at least three ground wires should be used.

When you run the car on the dyno, the engine load may more than you could put on it on the street. The dyno load may actually represent more weight than your car. So there is more load on the engine than you could ever place on it on the road. That being said, the more load on the engine, the higher the duty cycle on the injectors. Did you run logging when on the dyno? Do you have more than one ground wire from the MS, through the DB37 cable, to the chassis? Try accelerating up a steep hill to try and replicate the problem. Then turn on logging and post the log results.

I'm thinking 7K for max RPM. I know I can build a 20+ psi L28 and get over 400WHP. That's not what I'm shooting for. I like the low RPM power of a quick spooling L28 turbo (300ft-lbs at 2.5-3k RPM). I want it to push me back in the seat at low RPMs, and be real fast at the top end. I've go the stroker parts less the pistons. Either way I'm going forged, so the stroker isn't costing me anything, but should add more power on the top end at 7psi and no intercooling.

Starting to think more about the new motor buildup. I've built low compression 300WHP turbo motors, and mid compression (8.5:1) supercharged ones, now I'm thinking something different. I want the high RPM power of an NA motor, and the low end torque of a quick spooling turbo motor. Low boost, but fast spool-up is the key. Want to have great throttle response similar to NA motor. WHP goal of 300-350HP. Hear is my plan, please comment: L31 (LD28 crank, L24 rods, bored 3mm over) 9.0:1 CR (forged flat top KA24 pistons milled 0.6mm) Metal gasket Full port and polish P90 (stock height) One of the turbo grinds out there for a camshaft (suggestions?) Port match intake and exhaust manifolds L28ET exhaust manifold Intake manifold and throttle body(s) top secret Ball bearing T04E/T3 with stage 3 turbine (other suggestions?). Maybe add water injection (no intercooler) ~7psi boost Programmable EFI of some sort So yes, I could run an intercooler, but frankly, I don't want to look at it. I want it to look sparse and clean under the hood. No unnecessary plumbing. No bling! Lots of black krinckle powder coat. All comments welcome.

That filter will work fine for well over 320WHP. If you get one, let us know what you think. Sometimes when dyno tuning if we run out of things to do (car is done, and ready to come off the dyno), I'll take the one of these cone type air filters off to see if there is any noticable difference in power. On all occasions, there was no measurable difference between no filter, or a K&N. All were turbo charged. My car runs 2.25" IC tubing, with a 2.25" inlet K&N filter just in front of the radiator support. No difference in power with or without it.

You can't weld the Ford rind to the Datsun damper. The damper is some sort of cast. The weld just won't stick. Then I tried braze, and it got the damper so hot that the rubber damping material melted, and the pulley came off. Use bolts. I ended up having a friend make a trigger wheel on his plasma cutter (see earlier posts). I then bolted it to the damper, and trued it up on a lathe.

OK, I took some more measurements and found the following: The LS1 coils do not saturate until around 8ms, but the spark energy does not increase significantly beyond 6ms. So stick with a dwell setting of 5-6ms. This will keep the coils cooler, and extend their life. I also measured the dwell for 2nd gen RX7 coil packs (I run these on my turbo car). The max dwell should be in the 1.6ms range. Any more than that and you are just heating up the coils and modules. The LS1 coils have a much hotter spark that the RX7 units. I may switch over to them on my turbo car, we'll see.

The IAC algorithm is trying to maintain a stable idle, where the boost controller tries to maintain a stable manifold pressure. But the way it modulates the IAC valve on and off is similar to a boost controller. Yes, the MSII could do it, but it would take some significant code changes.

The boost controller doesn't just open the waste gate at a certain pressure and then leave it open (this is how a manual valve works), it modulates it on an off very rapidly. This is how more precise control is obtained. It is essentially a feedback loop. The ECU monitors manifold pressure, and then changes the duty cycle on the pressure valve to maintain a preset pressure. This is why the configuration control parameters for the boost control are so important.

I think it has a lot to do with the waste gate actuator, and how fast your valve is. I would set it somewhere in the middle to start.

Depending on the frequency at which the FET switches, you may not see the LED blink. The human eye can not even see 60Hz! I'm sure the PWM rate on the boost controller FET is much higher than what the eye can see. The LED will most likely appear on, but slightly dim.

Do your SU TBs have the same bolt pattern and bore diameter as the original Hitachi SUs used on 240Zs?

I'd double check you fuel lines, filters, fuel pump, regulator, and wiring to be sure everything is connected OK. Then I would spend some $ at a reputable dyno shop. Trying to drive it around and tune, is a waste of time. Get it on a dyno for an hour or two and be done with it.

Fender lip rolling + Bondo = disaster. I just cut the lip off mine with my die grinder. Then I used some undercoating to seal it up.

You need 8" wheels with a +0.5" offset to clear 245s in the rear. And then you also need coil overs (to clear the wheels), and you need to trim the fender lip. If you are running stock ride height with stiffer springs, you may get by with 0 offset and 245s. But there may be that one bump that does a tune on your fenders.

The wheels look great. How is the construction? Do you think they are safe for track days? Any rubbing problems in the rear? I run 16x8s with a +0.5" offset. This lets me run 245-45ZR16s. But even with the extra 1/2" of clearance, they still rub on big bumps in the rear. The 4x4 calipers stick out even more than the AZ Wilwood setup. On my track car I have the 4x4 calipers with the vented rotors, and I have to run 1/2" spacers with Panasports. My turbo Z has the Wilwoods, and they clear the Panasports fine. The problem with the spacers is that you may not have enough thread in the nut after putting the spacers on. I have 1/2" longer ARP studs on the track car. The other option is to mill the fins off the caliper. the fins stick out at least 1/4" from the caliper body.

Those numbers are fine for a 240SX TB. The actual TPS determines the WOT number (or resistance). Even two identical 240SX TPS may have a different WOT number.

Yes you can use any rail, and a stock regulator. If I build one, I will use a Megasquirt to fire the injectors. I think I may have a way to measure the minimum injector opening time for a given injector. I'll try it in a few days and post the results.

Do you have RPM in Megatune? If not, nothing will work. I have the sense+ connected to either LED terminal. LED have about a .7V drop across them, so either terminal will work. Connect the sense- to the same ground for MS and the coil. The LED will be on all the time, the pulse frequency is too fast for the human eye to see. You must set the output to me not inverted.

LED17 The MS needs an input tach signal to do anything. Get a stimulator, it will allow you to control RPM, IAT, CLT, TPS, and O2.

Is your fuel rail dead ended? Do you have a good size return line (3/8" or bigger)? This should be enough to keep the fuel cool. Filling up before your dyno session will give you more thermal mass in the tank.

Do you have a stimulator? The "output inverted" box should be set to "no". Unless you have a crank trigger wheel setup on a drill or something, you need a stimulator with MS setup for a distributor. Only spark output A will be functional in this mode.

Injector flow benches usually test injectors at 43psig, and 80% duty cycle. This method will not identify a lazy injector. OEM 280ZX and 280ZXT injectors after cleaning usually flow within 1% using this method. BTW, I use Witchhunter Performance for all of my injector cleaning and testing. Gordon does great work. Injector staging is one way to get around idle problems with big injectors. The early Wolf units have a very coarse fueling resolution. On my turbo car I run stock ZXT injectors for a good idle, and then use a couple of staged ZXT injectors that have an opening time of 80% of the primary ones to provide enough fuel under boost. The staged injectors do nothing at idle because the opening time is too short (80% of primary). SDS makes a nice addition injector controller. You can also use a Megasquirt for this purpose. I was thinking of building a flow test bench at some point. Thanks for the link!

Another thing to keep mind is that an injector is an electro-mechanical device. Injectors have a minimum opening time that is determined by the mechanical design. This is limiting factor, not the ECU. If the injector has a minimum opening time of .1ms, then the ECU should be capable of at least one half of that for good fueling resolution. Used injectors can have much different minimum opening times resulting in some that might be lazier than others. So if your engine doesn't require much fuel at idle, getting a smooth idle from big injectors may be difficult.

Yes, you can use the LED transistor directly. You need to setup MS for the proper mode to get the correct waveform from the LED output. "Code base and output functions" need to be set so "Spark Output A" come out of LED17. What are you going to use for a trigger wheel? You need to configure that too. I am just using it in distributor mode for this test.