z-ya

Sounds like SDS has an issue with their air temp compensation. Or, because the intake is getting so hot that it is beyond the scale of the sensor (unlikely). By moving the IAT sensor, you are fixing the symptom, not the problem. Moving the sensor is compensating for some calibration error. An example of why the sensor needs to be in the intake manifold after the TB: Under heavy acceleration in a boosted application, lots of air is flowing through the system, so the IAT in in the IC pipe will give you an accurate reading. But as soon as you let off the throttle, the throttle plate slams almost shut, cutting airflow through the system. In this instance, the air in the IC pipe is MUCH cooler than the air in the intake, but it is the temp of the air in the intake that is important to the ECU. I have seen this behavior, and if the air temp compensation is not correct, the engine will stumble a few seconds after the throttle plate closes. The is due to the fact that now the AF ratio is wrong for the given intake air temp. Once the throttle is opened up a bit, and the temperature drops, the stumble goes away. I have seen the temp jump over 10 deg C (50 F) after a full boost dyno pull. After making a correction to the air temp compensation, the problem went away.

The stock L6 Bosch injection is batch fired. You can run the MS in a simultaneous (batch) or alternating mode. This is great if you have a 4 or 8 cylinder. Since the MS has only two injector outputs, you can't do alternating on an L6 and have three injectors on each output driver. I've installed Wolf 3D systems that have 4 injector outputs, so you can do alternating injector firing on any engine type. BTW, your L6 will run in alternating mode, it just won't idle all that smooth.

Do you need to run the AFM in SCCA ITS? If so, does it need to be fuctional? The Megasquirt is a speed density system, so it doesn't require an AFM. I did read somewhere about someone using the stock harness and ECU case for a Megasquirt, so I think it is possible. You need to change the calibration tables for the Nissan sensors, and you also will need a 240SX (resistor type) TPS (may not be legal). They allow you to run any EMS that will fit in the stock box and use the stock harness? This rule is in place just to make it difficult to make these kinds of mods. There is no other reason besides the fact that retaining the stock AFM will limit your performance. What SCCA should require is to retain the stock AFM, even if it isn't actually doing anything (kind of like a restrictor plate). Then they should allow you to use any ECU, sensors, and wiring harness. Using the old harness will effect reliability, leaving stranded race cars on the track. When I do an MS install, especially in a competition vehicle, I always start with a new harness, connectors, and sensors. Do it now, and save yourself a lot of headaches later.

Moving the IAT sensor upstream of the TB in a IC pipe will just give the ECU false air temp readings. This is because the air in the IC pipe before the TB is much cooler than the air in the plenum. Make sense? If you are having heat soak problems when the IAT sensor is in the plenum, then your air tempreature compensation algorithm is out of calibration for some reason. The sensor needs to be as close to the intake port of the head for maximum accuracy, period. The ECU will compensate for any extreme intake temps so that heat soak never happens.

You want the sensor where it will get the most accurate reading of intake air temperature. With only one sensor, the best loaction is in the intake plenum somewhere in the middle. This way you will get somewhat of an average temp across all runners. As far as heat soak, you will have heat soak no matter where you put the sensor. The MS will compensate for temperature change in the intake (uh, that is what the IAT sensor is for). So putting the sensor in a place where it will inform the MS that the intake temp is high is important. The cold start injector hole is a good place, and so is the hole that is centered in the plenum, that is where I put them.

Hear is a dyno sheet for a car I helped build and tune: Stock L28ET block, head and cam. T3/T04E with stage 3 turbine. 13psi. 420cc/min injectors with Wolf 3D engine management. 326WHP.

I found out htis week that you can't weld the stock Ford wheel to the balancer. Whatever the trigger wheel is made of, will not TIG weld. So we tried to braze it, and as you would expect, it heated up the balance so much that the rubber melted. The balancer is junk now. We are trying to make a trigger wheel from steel with an automated plasma cutter, I'll let you know how it works out. Finding a 81' turbo balance is a good idea because you can just bolt on the trigger wheel. If the custom trigger wheel comes out OK, I'll have him make a bunch of them. Paul Ruschman (Braap), bolted his on. I may try this iof we can't make a wheel.

Hear are dyno plots from when my Z was running stock boost and a stock T3: (see thumbnails) Hear is my latest dyno pull running 12psi with the same turbo:

Yes, the turbo distributor is locked, and controlled by the ECU. In a boosted application, just using an NA distrbutor with the stock advance mechanism, and MS for just fuel control, will not produce anywhere near the drivability and power as either EDIS or a locked distributor and MSnS-E. You can lock the advance mechanism in an NA distributor and acomplish the same thing as a turbo distrbutor. I beleive that you will need to use two HEI modules in this setup, one to provide proper input trigger voltage to the MS, and the other to drive the coil on the output of the MS. A little more involved, but not that much more difficult.

I would use the 82-83 turbo distributor as others have, or go distributorless with and EDIS setup. The NA distrubtor has the wrong advance curve. So you will have to run less timing overall making it slugish when not in boost.

Jon is right, you will make 160 easy with that setup (as long as it has P79 flat top pistons), but for another $150 you can make a lot more. Plus you wil be able to run a lot more advance. I would run 460 lift max, as you can still use the stock springs. Also, why not just pick up an N42 head, it already has the bigger valves, and it will support an internally oiled cam. Give it a valve job, install the new cam an lash pads, and you set to go. I got 165WHP from a F54-flattop block with a stock N47 head and cam. I could only run 26 deg of advance with high test. If I had a mild cam in there, I could probably push the timing over 30deg advance. I am putting a 460 lift cam in it now, but I'm also swapping to a P79 head, and adding a supercharger. I will make a dyno run with the belt off just to see if I gained anything with the cam and more advance in exchange for CR (was 9.8:1, will now be 8.5:1) Pete

Thanks for the clarification, I didn't realize that it was absolute pressure.

Am I missing something or are all you guys not controlling timing at all below atmospheric pressure? What is you idle timing? Anyway, you have way too much advance. Plus, your pressure scale is too wide, so you are not getting all the adustability you could. How much boost do you plan on running? Set the max kPa value to that number. 240kPa = 35psi. You will never run that much boost so that part of the map is not being used. 1psi=6.7kPa, so at around 10psi you are running 34+ deg advance above 200RPM. Ouch! I run around 26deg max at 12psi with a 7.5:1 L28ET. I would set you pressure scale to go from -60kPa to +105kPa. This will give you a timing adjustment range from -18inHg to 15psi.

Progress photos:

You could actually use the EDIS setup and a MS to control just timing, but while you at it, you might as well do fuel control too. The precise control of both fuel and ignition will always get you the most out of your setup. Update: My motor is getting close to going back in the car. I've got the supercharger mounted (I'll post pics soon), so any day now I should be getting it back in the car and fired up.

Nice job! I just painted my NISSAN cover with Duplicolor low gloss black. It came out great. Duplicolor makes great spray can paint.

You can do everything you need to do with current MS hardware. If you want crank trigger ignition too, you can run MSnS-Extra with Ford EDIS.

Have fun. Building, installing, and tuning Megasquirts is fun and rewarding. Just be meticulous with your wiring and soldering, it will save you a lot of time in the long run.

Yes, they need to be pressed out. Any automotive machine shop can do it for you.

I would think that if you tied the MS temp sensor input in parallel with a gauge, it may throw off the calibration. This is beacuse you will now have the impedance of the gauge in parallel with the sending unit. Depending on what the impedance of the gauge input is, it could throw it off by a lot. The MS input impedance is very high, so it would not have an effect on the gauge, but the MS would be getting incorrect temp data from the sensor. The Keep your stock 280Z temp sensor and gauge. It's always good to have a second source for engine temperature readings.

Did you verify that the MAP sensor is working? You should see the MAP change in Megatune as you change the throttle (when the engine is running). If it doesn't move, you could have the MAP sensor in backwards. Also, did you calibrate the TPS? In Megartune: Tools => Calibrate TPS. Click "Get Current" button when at idle, and at WOT (shut off engine to calibrate TPS).

If you are runnig a resistor pack in series with your injectors, then you can set the PWM to 100%. If not, then you need to play around with the PWM settings. I for one like to have the resistors there to protect the output transistors from making a mistake in Megatune.

NA are 19lb, and turbo are 26lb.

Ed, Try experimenting with the following parameters: - Alternating vs simultaneous injector staging. - The required fuel setting - Injections per engine cycle If all is OK with your MS and wiring, you should be able to get a good idle using these parameters. Only make adjustments after the motor is up to temperature. PM me, and I will send you a couple maps. I have one for 19lb, and one for 26lb injectors.

I machined the pulley, and made a sensor bracket this weekend. I made the VR sensor braket from some thin wall steel tubing, and 1/8" plate steel. It came out OK. It is not pretty, but it should be strong enough. I may make another bracket while I've got the motor out. I machined the entire outer pully off. Once I time the trigger wheel, I will have someone that is good at welding weld it to the damper.