Those diagrams are NOT from a Z32. Notice they call the soleniod "factory boost control" Not "safety boost" This diagram looks like its from a Supra or some car where the ECU controls boost level. Our cars dont have that.
Tekky is spot on again. I have pictures somewhere of the 2nd set on my Zed, they were in the Factory Line from the Actuator about 7 inches from the Actuator. All that aside, like I said before, the best thing to do if one is worried about any of this crap is to just run new lines direct from Actuator to MBC/EBC. Sure you'll lose Safety Boost function, but theres no screwing around with the plumbing either. MoulaZX
Ok, got it sorted out today - interesting results After checking and rechecking and double rechecking the plumbing, it was all good so the only thing left to test was the boost controller and disconnecting the safety boost solenoids. So, with the boost controller, I opened it up and took out the ball and spring. Sealed it up, and went for a drive. With the boost controller connected, without ball and spring (essentially NO boost control), the boost rose to 12-13psi. It would not spike above that, but it was higher than the stock 9psi boost. I have no explanation for this rise in boost other than that the body of the boost controller is quite restrictive (the outlet and inlet ports are only about 2mm wide), and it was perhaps acting as a boost jet by restricting the pressure. Don't know. But with the spring and ball back in place, it would shoot up way past 15psi if I let it. So next came the disconnecting the safety boost solenoids theory. Well, it seems, that on my car, a 1993 TT, with a turbotech V2 mbc, I need to DISCONNECT the boost solenoids for it to work properly. With the solenoids disconnected and the boost controller at its minimal boost setting, I got a steady 7psi. As I then slowly increase the boost level on the mbc, I was able to achieve a very stable 12-13psi without crazy spiking. Now, I dont know enough about the boost solenoids etc etc and exactly how they work, and there seems to be two modes of thought here on the forum; either disconnect, or leave connected. BUT, for this setup to work correctly on my car and allow me to control boost with a Turbotech V2 mbc, I need to disconnect them, otherwise very unsafe boost levels will result. So, maybe a stupid question, but could there be a difference in the boost solenoids function and activation between the years (1990 vs 1993) that could explain why on some cars they need to be disconnected and on others they don't?? I must admit, I would prefer to leave them connected. But if I want a mbc and more boost it seems I cant. Unless I take the ball and spring out of it and essentially use it as a restrictive boost jet. Considering, I rarely hit stock 9psi boost anyway, it begs the question why do I need more boost. I probably dont, but its nice knowing its there Thanks for all the advice guys.
Its from an article written on Z32s... I learned a lot from it when I stumbled onto it trying to solve my over-boost problem. http://www.thumper300zx.com/z32/factory_jets/factory_jets.htm But oddly enough, it makes no mention at all about the 2nd set of Boost Jets... MoulaZX
Its because what I told you is right. I had the same boost controller you now have and a 1990 TT, connected it would spike like crazy just like yours and disconnected it worked perfectly. Also I know Kieren, had the same issue. This exact situation as come about for many members before. Everybody jumps on the Tekky is right bandwagon without knowing what they're talking about. You just witnessed for yourself the results which speak for themselves. What they don't understand is Boost jets which are the same as restrictors need the boost to be bled off by the boost solenoids to work, without this the boost jets/restrictors/welding tip.. wont work because the pressure on either side will still be equal. Again if no boost is bled off by the solenoids even with a restrictor (where people seem to think there is one) wouldn't make any difference the pressure will still equalise and the waste gate will still see full boost. This in turn means the solenoids are in fact ON 12v applied to bring your car up to 9psi and keeping it there under normal circumstances. If no boost is bled off then your not going to get any higher than wastegate pressure. This is why they must be unplugged/off/closed/no 12v applied, for the mbc to work correctly, otherwise your running the stock boost control & the mbc at the same time.
Challenge !!!!!!!!!!!!!! Here's a question for you. For the ECU to turn the soleniod on and off like you said to control boost. Where is it measuring boost pressure? Show me a vac/boost pipe to a transducer that enables the ECU to measure how much boost you have so it can control it? And dont show me a picture of boost transducer that sends to the boost guage in the instrument cluster. Then, post up your theory on TT.net and see how far it gets you. Shame you never noticed the second restrictor before
It does it switches the solenoids ON which brings the car up to 9psi by bleeding off pressure to the wastegate actuators. Then it switches them off for safety boost. :rofl: The set wastegate pressure + the size of the restrictor and by bleeding off air by the stock boost solenoids is calibrated at the factory. The ecu doesn't measure boost pressure. I'm not a keyboard warrior I started off with this very MBC then upped it to a TurboSmart Eboost, I've been there done that.
on my old 90 model I did exactly the same thing plumbing wise, not with the same controller though and I could only get it to go to 13psi and never spiked above and I drove it like that for a week and then checked out the mbc plumbing cause it was running a little rough one day and i figured well that was the last thing that i did to the car so id check that out first and the boost hose had blown off the mbc and i wasnt able to fix it at that point, so i just plugged the hose up and it stayed like that for ages and only ever boosted up to 13psi, I never unplugged the boost solenoids either.
Like I said above. You leave the soleniods connected and put a small bleed hole in the line to the actuators and it will work and have safety boost
That may have been a bleed valve style boost controller which is different again. However relevant that may be I'm not sure. There are two types of MBC's bleed valves and ball & spring which in theory stay shut until they snap open.
The MBC already has a bleed hole built in to bleed off air between itself and the actuators. This was mentioned in the very first post and is widely known.
My last zed had the boost solenoids connected along with a ball and spring boost controller. No issues whatsoever setting boost levels.
Maybe you were already in "actual safety boost" because as you can see if the solenoids are active which they need to be if they're plugged in and working then you will be spiking. Waste gate pressure + a restrictor + boost solenoids bleeding off pressure calibrated correctly at the factory is how stock boost is achieved, so what you say makes no sense unless they were stuck shut despite being plugged in or not receiving 12v. You'd be running with stock boost control factory set to 9psi plus your mbc at higher psi. If it worked fine can you explain how? and when you say connected to what? power or still hooked up via hoses?
Many members have had their safety boost solenoids hooked up whilst having a mbc. Thats why there is such widespread confusion on this topic. My zed was not in safety boost. Hoses and electrical connectors were hooked up as per stock. Look up the instructions on installing boost jets for the 300. They mention nothing on disconnecting boost control solenoids either. How or why this works on some zeds and not others is a mystery as we are bringing to light right now. I understand the logic behind the spiking etc but am reporting no ill findings on my behalf nor on the zeds I have helped install mbc's on in the past.
Many members also have had to disconnect their stock boost solenoids. Boost jets are totally different and NEED the boost solenoids bleeding off air to work. I'll paste an article here. Enough posts have been made now that everyone pretty much knows the "FACTORY BOOST JETS" exist. Well, just to close the case, here you go. On each side of the car, there are the factory boost solenoids. A short hose from the intake/inlet pipe (to the turbo compressor inlet) connects to the "top" (seen on bottom in these pics) port of the solenoid. This is a vacuum signal and always a vacuum signal. The factory boost signal hose (comes from front of engine bay from TB pipe nipple) connects to one other port on the 'T' and the other port has a hose that goes down to the turbo actuator. The bottom port of the solenoid has a small section of hose that then connects to a metal 'T'. On this hose you will find a bulge. In the bulde is a small restrictor. Note that this restrictor is not directly inline with the boost signal line, so you could argue that it is NOT a boost jet, but rather a solenoid signal/vacuum restrictor. FACTORY SETUP The factory setup is described in the diagram above. Each side of the engine has this setup. The wastegate is PRE-SET to open when seeing a boost signal of about 6-7 psi, while the setup is "calibrated" to run the engine at about 9-10 psi of boost. When the factory boost solenoid is OPEN (12v signal) the actual boost signal is bled off through the solenoid into the intake tract... So, the wastegate actuator sees less than actual boost pressure (about 3 lbs less). If the hole in the restrictor were smaller, the bleed off would be less...if bigger, more. If you were to plug the line (or remove the solenoid) and have a direct boost signal, the boost would be limited to 7 psi. When the factory solenoid is closed (12v signal cut [safety boost, cold engine, or startup]), you see about 7 psi max boost because the actuator is receiving the actual boost signal pressure instead of the "calibrated" signal. One problem with this setup is that the wastegate actuator sees a gradual rise is pressure. While boost is being introduced, the signal bleeds off incrementally. So, when you are at 8 lbs of boost, the actuator is seeing 5 lbs and can begin to open. Instead of opening only when the exact preset level is matched, the operation can be slightly inconsistent, creating a bit of lag in the spooling of the turbo. FACTORY SETUP (in SAFETY BOOST) FACTORY SETUP w/AFTERMARKET BOOST JETS Now then -- you decide to install boost jets into the boost signal line while keeping the stock solenoids installed. You put in .045 jets and are now running 14 psi. The boost jet is restricting the actual boost signal, "tricking" the system and showing the actuator less pressure (boost) than actual boost. The small hole in the boost jet allows less pressure through the signal hose (about 4-5 psi in this case). The factory solenoid further bleeds this signal (about 3 psi). The result is that the actuator sees 6 psi of pressure when in actually you are running 14 psi into the manifold. Another issue here, the signal is bleeding to the actuator as boost increases. So, when you're at 10 psi, the actuator sees 2 psi. When at 12, actuator sees 4 psi. The actuator may actually start moving once pressure is getting close the operating opening pressure, as in the stock setup (discussed above). AFTERMARKET BOOST JETS w/FACTORY SOLENOIDS REMOVED Now, you remove the factory solenoid and connect the boost signal line directly to the wastegate actuator (or disconnect the electrical connector). You still have boost jets in the boost signal hose. What happens now? I was confused about this at first, but then the concept was explained to me on TT.net. If there is no leak, the pressure on both sides of the boost jet remains equal, even though there would appear to be a restriction of flow and less pressure on the other side. So, throwing in boost jets on a dedicated line to the actuators does NOTHING. However, if you remove the line or plug it completely, the actuator can never open and you will hit "infinite boost". ELECTRONIC BOOST CONTROLLER (EBC) with SOLENOIDS REMOVED (or unplugged) This also goes for MBC's you don't want the stock solenoids bleeding off air as they're designed to do from the factory to bring you up to 9psi. By disabling them they're closed and the only thing affecting your wastgate pressure is the MBC, the factory restrictor doesn't matter because the stock solenoids are shut. If the solenoids are left connected they will do what they're made to do bleed off pressure and mess with your mbc adjustment. All the sudden there is a different operation. (not a full or precise explanation, but you can find out all about EBC's on TT.net). The EBC solenoid provides NO SIGNAL to the actuator until the precise moment you reach the maximum set boost. What does this mean? The actuator sees NO PRESSURE and will not start to open until EXACTLY when full boost is reached, at which point it opens immediately. The EBC either opens and closes this signal quickly or will bleed a bit of pressure (like the factory solenoid) to maintain pressure at exactly what is set. This provides better spooling and quicker boost response. Advantage EBC. THERE YOU GO.
All of the above I agree with. Just reporting my own findings. Essentially, the stock solenoids bleed off air, and soo does a manual boost controller. The stock solenoids interfere with the mbc yes, but not enough to make them ineffective. Well in my experience anyway. All this being said, and considering others seem to have had issues, I'd say I will disconnect the boost control solenoids upon my next installation to avoid any possible issues.
Yea I had the turbotech mbc myself and unplugged the solenoids, it worked perfectly but when I had another member come around to help me with some work he plugged the solenoids back in and when I took it for a drive it was boosting limitlessly and spiking like crazy. Unplugged the solenoids and it returned to the mbc operating perfectly. Getting into a shit fight with people who don't know what they're talking about and posting rubbish like "CHALLENGE" being labelled a "keyboard warrior" when I'm providing factual information with every post makes me wonder why I bother. Even Pex, jumped in while being incorrect. Is it that they've been here too long and cannot accept something they didn't already know? or just jumping the gun because they believed that some how a restrictor would lower waste gate pressure without it being bled off further down the line? Great job fellas that's promoting the forum.
The detonation sensor works up to a point, Its shut off over 3000rpm? or close to to that. driving these cars around in a gear to high for your road speed, laboring the engine, will get you detonation no problem same as crap fuel. So if anyone thinks the detonation sensor will somehow save your engine at 6-7000 rpm think again. I've used and fitted both an mbc and have an ebc now, in both cases the stock safety boost solenoids and associated pipes and restrictors were removed completely, My engine dose not detonate as far as I know, nor dose it spike. I stand by my original post, remove the lot and you wont have any problems.
agree only its the same as disconnecting the 12v supply to the solenoids (shut). We're really saying the same thing here, there's no difference as the associated hoses with them become instantly redundant. Its just like the case of the aiv's for example, you can remove it all or simply unplug the solenoid.
