V-mount = overboosting
12-10-09, 04:00 PM
#26
Well, my experience is limited to my own car. I hope that would not make you consider my logs as statistically irrelevant for that 
The only thing I may add is that I had R-compound tires, had full traction/load and it was a quite extensive, hard full throttle application, for 4+ sec
Maybe my WG flap does not open completely, that I don't know. But I tested the actuator with a Myvac and saw the rod starts moving at 7 psi and stops at below 15, and these are pressure at the actuator, equal to the compressor outlet, not at the [lower] intake manifold pressure, as logged. Turbos are still original, never opened or adjusted otherwise.
And you can clearly see from the charts that the boost creep is stopped at 17+ psi by the IGL beeing pulled down to 4 deg, more than anything else.
- Sandro
The only thing I may add is that I had R-compound tires, had full traction/load and it was a quite extensive, hard full throttle application, for 4+ sec
Maybe my WG flap does not open completely, that I don't know. But I tested the actuator with a Myvac and saw the rod starts moving at 7 psi and stops at below 15, and these are pressure at the actuator, equal to the compressor outlet, not at the [lower] intake manifold pressure, as logged. Turbos are still original, never opened or adjusted otherwise.
And you can clearly see from the charts that the boost creep is stopped at 17+ psi by the IGL beeing pulled down to 4 deg, more than anything else.
- Sandro
Understand completley, just saying I have ran this on a ton of setups over the years with pretty much identical results. However, 95% is on non-sequential cars.
12-10-09, 04:47 PM
#27
I finally semi-finished my v-mount setup. i also did the poormans non-sequential, battery relocation and rewired the fuel pump. I test drove the car tonight and it is overboosting, i hit 14psi and 17psi at one point. the car felt extremely fast but I am afraid of blowing either the turbos or motor.
If your IC set-up was previously stock, most likely what your experiencing is less pressure drop. Here is a test I did a long time ago about pressure drop in the stock IC and ducting.
https://www.rx7club.com/forum/showthread.php?t=236643
12-10-09, 07:45 PM
#28
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A manual boost controller cant help you any more than what I suggested. It will help you dial in a higher setting and hold it, but it will not make it boost less than I suggested. What I suggested makes the car run off the wastegate "spring"(actuator) and allows as little boost as possible. If it still boost creeps after doing what I suggested you need to port the wastegate.
So i replaced the hose with boost restrictor pill going from the primary intake compressor housing to the wastegate actuator with a 3.5mm silicon hose. It fixed the boost creep but now I only get 5psi boost.
Im thinking i may have changed the wrong hose. Just in case here is a pic of what i did.
12-11-09, 07:04 PM
#30
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can someone tell me if i changed the correct hose in the above picture, or tell my why i am now only boosting 5psi after removing the pill located in that hose?
12-12-09, 12:53 AM
#31
The problem with anything other than dual independently controlled EBC solenoids (the stock/PFC configuration) is that the wastegate and precontrol atr not held completely shut or completely open in order to maximize spool and top end.
Before transition, the wastegate should be held completely closed (solenoid at 100% duty) to maximize the amount of exhaust hitting the primary turbine. The precontrol is used to regulate boost before transition. After transition, the precontrol should be completely open (0% duty) to maximize exhaust flow to the secondary turbo. This is how the sequential turbo boost control logic was designed by Mazda. It is the best design. It maximizes both spool and top end. The movement of the actuators is detailed in the service highlights document and the solenoid duties are explained in the ECU pinout of hte workshop manual.
It's pretty much impossible to achieve this behavior without a PFC or another standalone. An MBC can't do it. A single EBC can't do it no matter how you hook it up. The only way to recreate the factory logic with external EBC's would be to buy two AVCR's and adjust solenoid duty by rpm. The PFC does it automatically without any user intervention, and the factory solenoids can be replaced for cheap with the same style solenoids used in any aftermarket EBC (Greddy, AEM, etc). OEM-compatible connectors are also available for aftermarket boost control solenoids for a painless installation.
I have discussed this and other things like restrictor pills at great length in this thread: https://www.rx7club.com/3rd-generation-specific-1993-2002-16/why-engine-so-damn-complicated-part-1-sequential-turbos-demystified-841821/
Before transition, the wastegate should be held completely closed (solenoid at 100% duty) to maximize the amount of exhaust hitting the primary turbine. The precontrol is used to regulate boost before transition. After transition, the precontrol should be completely open (0% duty) to maximize exhaust flow to the secondary turbo. This is how the sequential turbo boost control logic was designed by Mazda. It is the best design. It maximizes both spool and top end. The movement of the actuators is detailed in the service highlights document and the solenoid duties are explained in the ECU pinout of hte workshop manual.
It's pretty much impossible to achieve this behavior without a PFC or another standalone. An MBC can't do it. A single EBC can't do it no matter how you hook it up. The only way to recreate the factory logic with external EBC's would be to buy two AVCR's and adjust solenoid duty by rpm. The PFC does it automatically without any user intervention, and the factory solenoids can be replaced for cheap with the same style solenoids used in any aftermarket EBC (Greddy, AEM, etc). OEM-compatible connectors are also available for aftermarket boost control solenoids for a painless installation.
I have discussed this and other things like restrictor pills at great length in this thread: https://www.rx7club.com/3rd-generation-specific-1993-2002-16/why-engine-so-damn-complicated-part-1-sequential-turbos-demystified-841821/
12-12-09, 06:34 AM
#32
We are very lucky to have on this forum such knowledgeable, talented, patient and generous people - like arghx and many others - willing to share their knowledge and experience. Take advantage of it. Read, study and understand religiously their threads and posts.
If you are only getting 5 psi, most likely you are just not applying enough throttle. You need to apply full throttle for several seconds with no hesitation, to test for boost creep. Do it in 2nd and 3rd gear. Again, logging would be of much help, by providing objective data and permanent reference for diagnosis.
- Sandro
12-12-09, 12:23 PM
#33
So i replaced the hose with boost restrictor pill going from the primary intake compressor housing to the wastegate actuator with a 3.5mm silicon hose. It fixed the boost creep but now I only get 5psi boost.
Im thinking i may have changed the wrong hose. Just in case here is a pic of what i did.
Im thinking i may have changed the wrong hose. Just in case here is a pic of what i did.
12-24-09, 11:16 PM
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ok so i fixed the low boost problem after installing the aem tru-boost controller. I was still getting creep so i *temporarily* installed a 2.25" restrictor plate between the MP/CB and fixed that. i also installed the PFC and i plan to get it tuned after christmas.
thanks to all for your input.
thanks to all for your input.
Last edited by jdm538; 12-24-09 at 11:19 PM.
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