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The reason I mentioned the TT CA ECU is that unit is populated with all of the hardware to run every option for the outputs. Nissan did not populate all of the components for other models of the same box. I could tell this was an early manufacture as most places did not populate all of the hardware back then. That has changed in many cases with the use of the software options, and it is cheaper to manufacture one board then a number of boards. The software, like Bernard mentioned enables, or disables various options and outputs as each model of car required.

Also, don't forget about the THREE fan control lines that can be configured on a temp basis. I haven't messed with any of those outputs, they are a relay control line. I can check, but I do believe it is possible to adjust the temp settings to act like some other control line for whatever like Bernardd mentioned. Then if you get the 90-92 Twin Turbo ECU, then you have two additional outputs for boost control, so there are alot of options to play there to trigger a number of different devices. The SLOP in the timing. I have looked into this some time ago and what I did was to match the gear,shaft, and oil pump take up the slop for the most part. I think I was seeing a deviation of about 1 degree of timing. I realize there are better ways to do the smae thing and get a fixed trigger off of the crank directly, but for the most part 1 degree of timing is not going to matter all that much. I NEVER run the car on the verge of pinging, I always back off the timing a degree or two just to give me a little safety margin. I have thought about doing a trigger wheel of the stock chopper, just bigger to fit to the damper, but that is a little more involved then using a hall sensor. The trigger setup Nissan used is an LED type configuration in the Infrared light spectrum. That is the challenge, getting the sensor on the damper, and sealing all of the light from outside away from the sensor. It may not be that critical, but I need to test a prototype to get the answer. I haven't had any problems triggering from the distributor, but it does take the turbo distributor and some modifications. I made a distributor for my car and I did a sceond unit for Bernardds car. I don't think he has any problems either. So for the money, seeing that you can pick up an ECU off of ebay for under $100.00 dollars, then what the heck. The hard part is the harness, and if you are like me then you spend more on the harness then the ECU. I made my system totally plug and play for ANY 280zx turbo car. I also upgraded all of the EFI relays to a Nissan 80 Amp part, and for the O2 sensor, a 30 Amp part. I got both of the relays off of an M30 car for the anti lock brakes. I have the relays, the box, and cover to run my setup. I realize most people will not take the time to do that upgrade, as it is difficult to reuse the relay terminals, and solder them after you have them the way you want, but for me, that was the very best option I could find without spending another few hundred for a similar relay setup. The Maxima and Z32 box solved all of my ignition problems, and the large injector latency problems that you may get with the older boxes from Nissan, and there again, there is a fix for that unit, but I did not want all of the added hardware to get the unit to operate the way I needed it to. But, I have other concerns right now, like getting my fuel lines back from Classic tube. They really screwed up this upgrade for me, so I fired them and had my lines sent back to me, hell it only cost me about $100.00 in shipping to find out they were flakes, and I still have to get my lines completed.

I have been reading this again, and one thing sticks out for me. The spark, which was one of the reasons I dumped the Z31 ECU. I had too much duty cycle at idle, and I was a little shy on the high rpm side. The SINGLE coil setup was not a good fit to the high RPM's and effective spark to begin with, and I can tell you I tried all of the adjustments that were available in the Z31 unit, and also the M30 unit. THE SNGLE COIL setup is not good enough for high boosted over 500hp applications. EXAMPLE: The MSD 6A box, very popular, works very good until you get into the 20psi boost levels. What is the first thing people do to stop a misfire @ high boost levels??? THEY DECREASE THE PLUG GAP! This is done because there is not enough SPARK DURATION or duty cycle. There is NO way around it. I tested the msd box; they advertise 17 degrees of spark duration, which equates to 500 microseconds or .5 milli seconds of spark duration. The spark gets blown out with the fuel, temperature, air, and most importantly, the cylinder pressures developed with a high boosted engine, NO WAY AROUND IT! The spark is to short in duration to effectively ignite the air/fuel charge. The single coil systems, have to produce spark six times more then the coil on plug setups, and from my bench testing of the systems, the single coil setup, whichever system we are talking about has to start cutting back the duty cycle of the spark, or coil primary charge time, to get every plug to fire. We are talking about effectively audio frequencies to the tune of about 45Hz according to my digital scope. I can see the charge time of the coil primary decrease on the scope as the rpm's increase. At the end of the day, regardless what I did to the ECU to make the spark duration longer at 7500 rpm's I was only able to get 900 micro seconds of charge time of the coil primary. As some of you may know, every coil has its specific coil charge time, and all of them are different. That is the reason for the various coils Nissan uses for specific applications in their cars, this is also true for fords and chevy cars. I tried 4 or 5 different coils, mallory, MSD, Nissan, Bosch, all of which I was not happy with the results, and in fact were not good enough to ignite my air/fuel charge at high hp. Now the M30 unit is better in one respect to the Z31 unit. The M30 went a step further then the Z31 unit in that they realized there were some problems with the spark duration and made the M30 unit sequential injection, that solved the problems with the X31 box at high boost/duty cycle of the injectors. The injector problems were the first thing I encountered with the Z31 box when I surpassed the 500hp mark with my engine. Due to the design of the Z31 box and hardware involved the ECU can only calculate the duty cycle to about 10 milliseconds of injector duty cycle. After that is surpassed and more injection time is required, the ECU then takes the current pulse to the injector, divides that by 50% and generates TWO pulses to get the desired TOTAL duty cycle for the injectors. What this did was to create, ON THE HIGH END rpm, and power levels, right around 5K rpm's consistently, a very rich spot in the 10:1 AFR range, and then a lean spot up to redline. Ask Tony about this, it was clearly shown on the dyno graph. Tony and I worked on the rich/lean condition for a number of hours on the dyno, and we could not get rid of the rich/lean spot but simply move the spot to a slightly higher or lower rpm level. I was finished with the single coil setup after that $1000.00 dollar two dyno sessions, and Bernard was involved on the second session as well. So the X31 ECU is perfectly fine for any L28 to 500hp maximum, and if you are using the MSD boxes you will never get consistent AFR's at that level with a boosted engine. I also dissected their box, had it backwards engineered, and when I found out HOW they were triggering the coil I stopped all work on mods for the MSD box. Not to get to technical, but what they do is charge a high voltage .1 microfarad cap, directly off of the step-up power transformer (450-550 volt output) and use the cap to set the spark duration which if you do the calculations of the cap charge time, plugging in the voltage, and power developed by the power transformer in the 6A box. The duration equates to 500 microseconds duration and that number can ONLY be changed with the output cap. Well that is not too hard to change, BUT with the longer duration what you get at 7K rpm's is the firing pulses fro each cylinder RUNNING INTO EACH OTHER, that basically KILLS the spark of the coil. Now that is a quick engineering evaluation of the single coil system. The other problem was with the power transistor, or igniter. The stock Nissan unit (on the 280zx car) pulls the 5 volt potential (or 5 volt square wave to the transistor base junction) to about 2.5 volts, chops the top of the square wave off at the rising edge of the wave and creates a waveform very similar to a saw tooth waveform riding on top of the 2.5 DC Volt potential. I designed a FET driver transistor setup that took car of that, and I thought I was out of the woods on the ECU ignition problem, but I was incorrect. I was able to get good spark duration at the high rpm levels, about .9 milliseconds to .85 milliseconds, and that was good enough, but when I brought the RPM's down to what would be an idle state for the car, the effective duty cycle of the transistor input, and output was to long. The duty cycle of the spark ended up at about 5 milliseconds to 8 milliseconds. Needless to say my coil got a little hot, so that was unacceptable as well. I started cooking coils, so that was another nail in the coffin for this box and application for my requirements. Single coil setups wll not be effective for high hp engines that are boosted period! Ever wonder WHY top fuel uses TWO distributors? I can tell you, having worked for Mallory electrc, the premier designer of magneto systems, the spark duration at high RPM's is not good enough to ignite the air/fuel mixtures. Hence, two distributors, and BTW clocked a number of degrees apart from each other to get the required spark to run the engine. My first guess would be 15-17 degrees apart. NOW! the sequential Maxima, Z32 ECU: I tested the units, and because they ARE FULLY sequential, (which was not the case with the redline webber ECU882 unless you have a cam trigger) you have a significant duration in triggers for the coils and the injectors. I ran the unit to 12K rpm's (and it loses its marbles at about 12,400 RPM's not to bad) and I still had slightly OVER 2 milliseconds between the pulses for the injectors. The coils measured about the same, plenty of time in-between pulses to fire the injectors, and fire the coils effectively. That is precisely WHY I went to the sequential systems. You can try to get more out of the single coil/single injection systems, but at the end of the duty, ALL ECU's will operate the same in perspective of the single coil systems, and that aint good enough for high hp and boosted engines. The OBD2 systems were designed for EMISSIONS NOT PERFORMANCE! So if you want to run the system go for it. The harnessing is a pain in the butt, I have built two harnesses, one for the redline system, and a second for the Z32/Maxima, what I call the big blue ECU connectors, and that ended costing me about $400.00 for the Nissan unit. The connector terminals for the connector, well lets say I got raped on the cost for them at bout $.75 each, and you can count the pins, 72 to be precise, then going to the junk yards for the connectors, sourcing the wires, and the biggest pain the butt was that I had to physically make my own crimp dye to crimp the stock Nissan terminals. Costly, but I am very pleased with the setup now and it fits my car exactly like the stock harness, all of the stock Nissan connectors, plug and play! So if you want to run down that rabbit hole headlong, go for it, but I am telling you there are better Nissan boxes to use on your car, and DON'T forget NISTUNE, it has full tuning capabilities for every aspect of the car, and is capable of triggering, anything you would want to trigger like stock waste gates, second fuel pump if needed, idle control from software, EGR if you want it. The O2 challenge for the Z32 box is that there are two units, but I have to do a little more research, but I believe I can use a single sensor (zirconia voltage scale sensor) and input that into a voltage input dual output digital pot (resistance out isolated but equivalent resistance output, or parallel output that is isolated) to input to the ECU, now how about that option. The second is the Maxima 92-94 ECU that uses the single sensor (and BTW, the connector and pin out for the Z32 box, LESS the second O2 sensor input) is identical, plug and play after you have the harness. The one thing I did not like was the volumetric efficiency table. This table is part of the main fuel map, BUT it only operates up to 3200 rpm's then the primary map takes over. I did not care for this table at first, but after working on the Z32 box, I think I am going to reinvestigate this box and see if I can get a little better resolution for the drivability of the car to 3200 rpms, which just happens to be the point that my turbo threshold is give or take 200 rpm's I wont tell one way or the other, as that is another debate, boost threshold, of which most of you in my opinion require to high of rpm's to reach, but again that is another debate. So there you have it, everything I was able to test and verify on the Nissan boxes. I really don't need to investigate any further, as these units will do everything I want them to do, fuel the car, and provide sufficient spark.

I see there is some additional interest in the CSR pump. For belt sixing what I did was to take the old belt, cut it to fit the new configuration making sure it was tight enough to tighten with the stock adjuster, and the billet adjuster from MSA for that matter, and had it sized at an auto parts store. That worked out well. So it just dawned on me that there is an upgrade that can be done to the pump. When I had this thing designed and built, it was built around the stock L28 water pump. I did not know at the time the LD water pump had a bigger impeller. Now I had the LD pump and made the mods to the front cover to fit the pump. I will be spinning it with a belt again, and removed the electric pump for all of my testing of the cooling modifications I have made to the engine. So if it turns out that the LD pump cooles the engine more effectively, then I think a very good test of the CSR pump would be to get back to the people at CSR and have them make a pump impeller based on the LD pump impeller. As I think most of you know by now, the LD pump impeller is about .200" larger then the stock L28 pump. I really did like the electric pump, but I have been testing the cooling situation associated with high hp L engines, so I started back at some known givens for my testing like installing the LD pump to start and go from there. I am pretty proud of this gesign modification I have done for this electric option and really want that as my final build, but I have to complete the testing first. Heating and heat soaking is my first priority. I could be wrong here, but I think my car is one of the best tests that can be completed on the pump. If the pump can keep my car cool under power then it is a snap, but I need the LD pump data first as a comparsion. A .200" larger dia impeller is significant, and CSR has the data I believe from the first pump design to compare with. I will have to call them Monday about making the upgraded impeller and go from there.

Who and WHY did somebody think a 90mm 3.54" throttle body be good for ANY L28 application? You are almost sized 50% more air flow then you will need to run even 650Hp. TOTAL OVERKILL and waste of time and money. Go with a 62mm TB and call it even you can make 650hp with that and a stock turbo intake manifold. Lone Wolf for a reason, good engineering would never consider that sizing for an L28 engine.

what you guys need to be looking at is the swept volume of the cylinder/piston assemblies. That will tell you exactly what air will flow into the cylinder under normal conditions. That is why the longer stroke and over bore are popular. For a N/A engine that is the key, so going with this wild cam and wild set of heads wil be not such a good fit to the lower rotating assembly. Now that was the basics for all of the combinations. The other things you need to look at is the volumetric efficiency of the engine, and this is where you will be able to make additional gains from the engine. The use of a tunnel ram intake manifold will help you out with this. You can push the VE of the engine over 100% provided you select the correct cam, intake and carb. Also keep in mind all of your efficiency will depend on the rpm's of the engine as well. John Lawlor has a book the engine math book that would really be beneficial for you to read, and just a good read for anyone and as a reference book so you don't have to remember all of the formulas. It sufices to say to install a 650 double pumper on a SB engine that really will only injest 600CFM is a waste of money and efficiency as example. There are some really cool parts out there at good prices, but if you don't have the lower rotating assembly to support the components then again you are wasting your money on parts that will not perform as well to components that are properly sized/designed for the complete build. Engine building gentlemen starts at the mathematical level and the engine is then designed around your math computations. Most of the really trick big port/valve heads are much better suited to forced air induction, and boy you can really make some power that way. Myself, I don't like guess work, I never have approached an engine build that way, decide what you want for power and build accordingly. Bigger is not always better, design on the other hand will always be the winner.

I have a stock turbo if you are interested. Just send me a PM if you want it.

Ok so with all of this discussion, I think I am going to jump off this cliff and have the cylinderhead done from #2-#6. I don't think #1 is really an issue as it is right at that large hole for the thermostat housing. I have completed #5 & 6, and was intending on doing # 3 but between 3 & 4 is difficult to do. I have already invested about 300 in what I have done, but the union T I used (swedgelock) is to big to get between 3 & 4 so a redesign is in order. I will get the 1/4 NPT fittings, do the intake clearancing for 3-4 use the A/N fittings and run the tubes to a common tube 1/2" but instead of using fittings have each tibe TIG welded to the common return pipe. I use a local welder here Master Craft Welding to do the work. This guys TIG welding is the best I have ever seen, very percise and very clean. I have him do the work I want to look good and be strong. I have already bought all of the -6 45 1/4" NPT fittings. Getting around the head stud between 3-4 is going to be the tough one, but I think it is doable. And just to make sure where it needs to go, I have a good door stopper P90 head I will section to make sure of the fitting locations. Why is it that every time I get involved in this stuff it starts costing me lots of money LOL, but its only money right? Anyway this is just part of the crap I am working on right now, and since I just dropped close to 4 grand on components for a race head what the hell!

I have run carter carbs on other cars and never had problems with leaning out with them. I have even run this carb on 4 wheel drive jeeps and trucks without a problem. I would recommend setting the float levels a little higher. I realize the carb is sitting 90 degrees out of its design install, but if the float levels are not high enough, then yes it can be a problem. Ever try to four wheel a holly, it doesn't go lean but it will flood the engine in a heart beat. So give the float level adjustment a try nd it should fix you up. What I use to do is to put the top cover on the engine, cycle the fuel pump and remove the cover to look at the fuel level. that will give you a good starting point. Dont worry to much about flooding as the carb uses the needle jets on the primary and it will not flood. You should be able to find a happy level that will work for you.

If you have the sensor in the oil pan, it is the turbo oil pan. All of the turbo pans have the sensor, and you are correct, it is the oil temp sensor.

Hi guys, I have the gasket getting machined along with some block work. I decided to make the changes in the basic HKS (Nismo) gasket to improve the cooling of the engine. When the gasket is completed I will send it out for copy. The changes in the part will not affect how it is put on a stock block, and work with a modified block. I am not going to talk to much about the block mods, as I am still doing the R&D to make sure there is an improvement and I'm not just pissing into the wind.

Hi Guys, I have also been looking for a gasket supplier. I think I found one, but I will need to send them my gasket to copy. I need to complete some work on the part before I send it to them. I expect to have a part ready for this place early next week. So the thinking is to have them make the stock bore dia and possibly an 88mm bore dia. I will keep you posted on this one. I am not sure of the cost, but they will be cheaper then the gaskets from Kamaraly, however you spell their name.

if you start to do your own parts, then before you buy stocked materials, look at the scrap racks for the material you want. I have gotten most all of my materials that way at a significantly reduced cost. If I had been sure of the type material today, I could have gotted a 6" long piece for 50.00 As it stands now, they are cutting a piece for me, and as I found out today, a 5" piece of round stock is hard to come by. 316L is really what I wanted, but the only company that had it wanted 214.00 for a 2" long piece of material. This stuff can be quite expensive, and I am guessing this is why I can not find the part in SS, because of the total cost to buy.

I just did a T3 inlet flange in 304. Not to bad to do, I used a conventional mill for the work. I did spend some time on the part. I am working on the outlet for the GT35R turbo. The four bolt outlet. I first bought a mild steel part, but it has rusrted to much for me in a short amount of time, so I will do this part as well. BUT, I bought a piece of 5" 304 round stock, 2' long and that ran me 100.00 for the material just to begin. I priced out a number of metal places one place had the dia I wanted, but they could not tell me the type of stainless steel. They mentioned 303, and that will rust. I decided to start with known material and that is what it cost the cheapest I could get the stock.

I had peaco do a billet aluminum crank pully for me. I decided against that part when I really thought about it. You do need a damper on the L28 no question about it. I have seen a few guys running a billet part, but I never wanted the problems it could pose for my application. I built both of the idler pullies for the belts. I have the standard 1/2" belt for the power steering and that part has worked out very well. I also did the old style 5/8" for the A/C and that part broke. I think I can do another part and make it not break. But I have other things that are more important at the moment. The aluminum idlers are good in my opinion, and they are not to hard to make.

What size is the exhaust turbine wheel? I have a exhaust turbine housing and end piece for a stock turbo like you are looking for. I paid 200.00 for the housing. Let me know if you are interested. The housing is setup for a stage 5 wheel.

A compressor bypass valve (CBV), also known as a compressor relief valve or diverter valve, is a vacuum-actuated valve designed to release pressure in the intake system of a turbocharged car when the throttle is lifted or closed. This air pressure is re-circulated back into the non-pressurized end of the intake (before the turbo) but after the mass airflow sensor. A blowoff valve, (BOV, sometimes hooter valve, not to be confused with a dump valve) performs the same task but releases the air into the atmosphere instead of recirculating it. The blowoff action produces a range of distinctive hissing sounds, depending on the exit design. Some blowoff valves are sold with a trumpet shaped exit that intentionally amplifies the sound. The TurboXS model RFL blow off valve is well known among tuners for this kind of design and some turbocharged vehicle owners may purchase a blowoff valve solely for the auditory effect even when the function is not required by normal engine operation. Motor sports governed by the FIA have made it illegal to vent unmuffled blowoff valves to the atmosphere. In the United States, Australia and parts of Europe cars featuring unmuffled blowoff valves are illegal for street use.[citation needed] Blowoff valves are used to prevent compressor surge, a phenomenon that readily occurs when lifting off the throttle of an unvented, turbocharged engine. When the throttle plate on a turbocharged engine closes, the high pressure air in the intake system is trapped by the throttle and a pressure wave is forced back into the compressor. The compressor wheel slows rapidly and may even stall, and the driver will notice a fluttering air sound. The rapid slowing or stalling stresses the turbo and imparts severe turbo lag if the driver accelerates immediately after the surge event. In the case where a mass airflow sensor is used and must be located prior to the blowoff valve, the engine control unit (ECU) will meter out excess fuel because the atmospherically vented air is not subtracted from the intake charge measurements. The engine then briefly operates with a fuel-rich mixture after each valve actuation. The rich mixing can lead to hesitation or even stalling of the engine when the throttle is closed, a situation that worsens with higher boost pressures. Occasional events of this type may be only a nuisance, but frequent events can eventually foul the spark plugs and destroy the catalytic converter, as the inefficiently combusted fuel produces soot (excess carbon) and unburned fuel in the exhaust flow can produce soot in the converter and drive the converter beyond its normal operating temperature range. One way to mitigate the problem is to reduce the boost pressure, which reduces the required venting volume and yields less charge overcalculation by the ECU. The air can also be recirculated back into the intake, a typical stock setup for cars with an upstream MAF sensor. The situation can also be corrected by switching the fuel metering system over to a manifold absolute pressure sensor, a conversion that usually requires a compatible aftermarket ECU or piggy-back fuel controller. The MAP sensor monitors the absolute pressure in the manifold at all times and will correctly detect the change that occurs when the valve vents, allowing the ECU to reduce fuel metering accordingly. Dump valves are fitted to the engines of turbo charged cars and sit between the turbo intlet and the throttle body. When transitioning from a boosted state to a closed throttle state (as in between shifts), due to inertia, the turbo continues to pressurize air, but the closed throttle prevents the compressed air from entering the engine. In this case the pressure exceeds the preset spring pressure in the dump valve and the excess pressure is bled off to atmosphere. Even with a dump valve the compressed air acts as a brake on the turbo (slowing it down), because the pressure on the backside of the turbo is at a higher pressure than on the front side (and the air actually wants to flow through the turbo backwards). A blowoff valve is a more elegant solution to this problem by allowing the turbo to "freewheel" when the throttle is closed (equalizing the pressure on both sides of the turbo). Unlike a dump valve a blowoff valve can be used at multiple boost settings without reconfiguration. Blowoff valves are sometimes incorrectly called dump valves because they serve a similar function, but they are very different solutions to the same problem. The two have been discussed at length by god who knows how many people. Myself, I choose to recirculate the air instead of venting to air. I don't like the rich/lean conditions the BOV creates.

Hi Nigel, that statement all depends on where the vacuum is coming from to open and close the valve. The recirculated system is behind the throttle plate, so on decell the BOV is open until such a time comes that the actuator spring overcomes the vacuum on the valve. By that time, you are either going to come to idle, or there abouts, the valve closes. When you are in a situation where you are on throttle and off throttle, there is the difference. The turbo essentially is spooled or almost at spool depending on your rpm and cam, and you don't get the rich lean conditions you have with the vent to air setup. So as I said it depends on how the system is setup, and for the recircukate setup the vacuum is always behind the throttle plate. I don't know about you, but every car I have heard with the vent to air setup has a very short lived vent time. I could be wrong, but it is closing the valve, at which point you get the system building pressure again. anyway.

I have read post after post about the "BOV". and I have yet to see many, or lets say VERY FEW people plumb in the BOV correctly to begin with. What is the BOV designed to do? Well the standard answer is to stop turbo back spin, and that is correct in the extreme case, but tht is not all the BOV was designed to do. Also with the unit venting to atmosphere you are killing essentially half of the work the BOV was designed to accomplish. Sure you get the little cutsie PsssssT! when the valve opens but that is about all. Venting to atmosphere will relieve the initial pressure from the turbo when you close the throttle plate, but nothing more, in fact when the valve closes, the turbo again will try to produce pressure, and you will again need to open the valve to relieve the pressure. I realize that the valve will stay open X amount of time, but it will close and you will be again at boost levels with a closed throttle plate. BUT, with the vent to atmosphere setup here is what happens to you. Now comes in the part you never hear about. The BOV is also designed to STOP the drag in the compressor, which is directly connected to the EXHAUST turbine. So if you build 22 psi of boost, (lets say 1300 SCFM) when you close the throttle plate the BOV opens and relieves the pressure due to the closed throttle plate. BUT, the turbo is still spooled and compressing air. When the BOV closes you again have boost that effectively is going NOWHERE, and it is creating drag on the compressor, at the same time you are introducing drag on the exhaust turbine wheel and it spins slower. What do you get for all of your efforts to help out the turbo? You get a turbo that has stress on the shaft turning the compressor wheel, stress on the exhaust turbin wheel and it begins to spin slower. I ask you, what good is that? NONE! In reality what happens is that the compressor is blocked off from moving air, drag is introduced on the compressor wheel, the exhaust turbine wheel has drag (now keep in mind the turbo at this point is still spooled) the turbo RPM's start to slow down, the exhaust gases are now moving slower and you create back pressure on the exhaust side of the head, spent gases get backed up and you start to experience exhaust reversion into all of the other cylinders that have open valves (intake or exhaust valves) to equilize the air pressure. You slow down the exhaust evacuation to the exhaust system, pressurize the turbin housing, all so you can have your little PssssT noise and think that is cool, well it is not cool when you stop to think about what is really happening. So for your cute little noise, what you get is a turbo shaft that really is still getting stressed, you get spent exhaust gases reversing flow path to the low pressure area, ANY valve that is open, you get crap air into the wrong cylinders, and a slightly less efficient burn for that cylinder, you get the turbo SPINNING SLOWER, that will take power and air flow to get back up to speed again, just so you can get your Pssst to begin the cycle all over again. Now I don't know about you, not being the sharpest guy that has lived, but that is a good loss of throttle response, and additional stress on the turbo, as well crudding up the rest of the induction/exhaust system before the inlet of the turbo. I think that is most undesirable myself. NOW, look at the recirculated BOV setup: You build boost, the air has already been metered, by the MAF or the MAP sensors. You close the throttle plate. Air pressure begins to build up and slow down the turbo RPM, you open the BOV, the already measured air goes from the turbo compressor outlet, and is then plumbed back into the INTAKE of the turbo, where it again is compressed and pushed out of the turbo compressor to the BOV and into the intake of the turbo again. The compressor has little or no drag to flow air, the exhaust turbine is still spinning at high RPM's, the exhaust spent gases are still flowing into the exhaust system, the turbo maintains its RPM, or close to it, you have no air metering to speak of on either the MAF based system or the MAP based system, so the fuel management stops injecting fuel, you get the fuel cut that stops back fires. When you tag the throttle, you have instant boost because the turbo is still effectively spooled. The BOV closes, and you build boost, the fuel is monitored again and the ECU injects fuel to make the engine run. The BOV was designed to relieve compressor pressure, recirculate air that has already been metered, maintain the exhaust flow, and stop exhaust gases reversion into other cylinders where it is not welcome. Which one seems better to you? BOV 101 class is over.

I have known about their head gaskets for some time, however, have you priced the total cost of getting one of their head gaskets? 23,100= $244.16 then you have $50.00 shipping, and about $25.00 Tax, for a grant total of $319.16 That is to expensive for my taste. Good gasket no question about that. To expensive no question about that either. Now it seems to get the benefits of a steel laminate gasket you will pay. Going the oring setup now is cheaper. The gasket (copper) 80.00 and the oring material is about 40.00 then you can RENT the groove-omatic from ISKY, and I haven't priced that tool Everything is going up. I bought the 1mm HKS or NISMO gasket for about $145.00 and that was not to bad. More then doubled.

Calculate the required air flow that the engine will require to get the desired hp. Then take a look at the compressor maps to find the best match for your goals. You will need to know swept volume of each cylinder. Then you will need to calculate the pressure ratio for each cylinder that will get you to the desired hp and multiply that by 6 then you will have a very good idea of what you will need. I don't recall off the top of my head, but the calculation is out there, and if not get a book by John Lawler engine math book and all the formulas will be there you will ever need to design a engine application.

First of all I have completed 5 setups on the turbo. I will talk about the TO4E setups. The fallacy that a smaller exhaust turbine housing is better might be true for a stock car running 7psi of boost and has a power band to about 4500-5000 rpm's. YOU WILL NEVER GO WRONG WITH A BETTER BREATHING ENGINE. That being said I will explain. You can get turbine housings from about .48 A/R .63 A/R .70 A/R .82 A/R and I believe 1.06 A/R (I have NEVER had need of a 1.06 A/R eahaust turbine housing) You need to size the exhaust turbine housing correctly for - RPM, HP, CAM, exhaust, static compression ratio, and for the desired power band. The idea of back pressure on the system is also misunderstood as well. The best rule of thumb is to make the turbo exhaust turbine the bottle neck in the system, not the exhaust system. The .63 A/R turbine housing with the stage 5 opening is the very best option for an engine that will run into the 7K rpm range. the .48 housing is good for an engine that makes power to about 5K rpm. so there are your choices for a good setup. The .82 A/R housing is best utilized for the engine that is making 650hp and higher, you will the spool rpm by about 300-450 rpm and spool later. My TO4E turbo with the stage 5 exhaust was well into spool @ 3400 rpm's that most here state. I could run down the road in second, take the engine to 3K and hold it there, when I tagged the throttle the turbo went to 23psi, no lag, no delay, to speak of. What a change in power, as I said it was almost uncontrolable. I don't really know why most of you get spool at 3400-3500 rpm's, that is a slow spool. I ran that turbo to 500Hp(@ the crank) and it was done! My next setup after the TO4E was a modified TO4E turbo running a 62-1 compressor. I also had a .70 A/R exhaust turbine housing. I lost spool and it went to about 3400 rpm's, easier to control the car that way. That setup got me past 550hp, and I ran that unit to 27psi of boost. I never got to dyno that setup, as it was on the car a short time. So even the .70 A/R housing moved the spool rpm up higher then the .63 A/R unit. I did do the back pressure testing on the TO4E setup, and @ 25psi of boost @ 7K rpm's I had 25psi of back pressure @ the inlet to the turbo. I did not even go to crossover conditions on the exhaust. Also, I have here or read somewhere that back pressure of 2 times the turbo pressure is acceptable. Hogwash! you keep the back pressure as low as you can period! once you have surpassed the boost pressure, you will NOT make any more power. The air/exhaust is going to flow, one way or the other it is going to move somewhere, so if you have high back pressure on the exhaust, then the ONLY place for the pressure to get released is up the intake, make no mistake, reversion is very real, and it is a performance KILLER. The .63 A/R turbine housing is the very best for an engine running 650Hp VERIFIED! The static compression ratio will determind how much boost you will need for the desired power, and the cam will also affect the compression ratio as well. Now the setup is the GT series garret turbo. GT35R with the .63 A/R exhaust turbine housing. This turbo if you look at the compressor map is a much larger turbo then the TO4E. I spool now @ 3200 RPM's and the car is much more controlable. The engine also makes 658Hp @ 509 foot pounds, that was on a dyno-jet, I think the Mustang dyno would read lower. I topped out @ 22psi of boost, and on the dyno, going from 22psi to 26psi made no Hp increases. So I either have a restricted exhaust system, or the .63 A/R housing is to small. I haven't taken the time to do the testing to determine which is the case. I suspect it is both the housing, and the exhaust system. TURBO CAMS, whoever said a good N/A cam was bad for a turbo car is full of BULL! I would be willing to say that MOST people know very little about cam dynamics and how they will affect the operation of an engine. I have even read a number of articles from known published authors, and cam people like Racer Brown that could not tell me what would happen to an engine running this cam or that cam for a turbo engine. Lets just say that the cam will affect the reline of an engine more then it will affect a turbo, I realize there are other variables to consider as there are some that just go crazy with duration, lift and the whole thing that will take a good build and make the engine a dog because of improper cam selection. I haven't published all of my testing data, but what I have posted will work for just about anyone here wanting to make power with the L engine. I can tell you another thing, the high Hp engines here are a short lived peek power due to heating, not much more then two pulls on the dyno within a few minutes of each other and the engine is to hot to run again until it cools off. I have listened to a good deal of opinions here and elseware on the topic, only to find like you most of what is being said are statements of opinion not backed up with the data, but rather from what they heard. I got tired of spending money only to find the results were very different then I expected. I have spent thousands and thousands of dollars to finally put an end to the opinions and speculation. I have the hard line data and I know EXACTLY where I need to go or do to get my desired results, no guess work, just raw data. So there you have it. I could still do further testing of my setup, but at this point I have other worries to contend with like over heating, and until I resolve those issues turbo selection is last on the list.

Looking at the angles of the chain from the crank to the sprockets you will have a good amount of loading on the sliders, and the tensioner. The nissan head if you look at how the chain runs is almost a strait shot at the cam sprocket, and the tensioner adds the additional tension on the chain. Your setup is much different and you will have problems keeping the chain tight if you don't ensure there is enough positioning tension to begin with. The chain is going to slop around and it very easily give you a high wear area on the sliders, and make the cam timing unstable. I think in your case a standard idler gear is in order for both sides of the chain. This will give the assembly a "static" tension that will not wear and then can be tensioned by a the stock tensioner. Otherwise I would be very surprised if the chain does not eat through the slider in short order.

The later model cars will have the resistor and the switch in the tps. I believe the 90 models and up will have what you are looking for. The differences have to do with the progression of the ECU's. The Z31 had only the switch, the M30 has the switch and the resistor, along with the 240SX cars. The TPS is the same basic configutration so any model will work. I would recommend a junk yard to get what you want, the yards are littered with the part you want.

I have a complete setup if you aare interested. wire harness, coil, CAS and distrributor, ECU , MAF if you are interested. Bernard and I, between the two of us, have installed every Nissan ECU. Currently both of us are running a Z32 ECU, and in my opinion this is the best of all the systems Nissan has done for the cars. You can get power form all of them Z31, M30 but both of these systems use a single coil and distributors. The Z32 system is fully sequential and will give you the best results for your time and effort. But as I said I have a complete system if you are interested.