Hey there, how you guys doing. I'm new to this site and I'm hoping someone could help me out with my current roadblock.
I purchased my 1990 300zx TT last year and I had little knowledge about the forced induction life until now, when I finally have the money to really run through the bay. It has a JWT ECU mapped for California smog regs, BUT... it has a ~90s HKS Electronic Valve Controller installed and appears to have never had the boost jets installed that came with the ECU. (I have no idea how this passed smog right in front of me knowing now that it is illegal in CA) Also, the EVC seems to have a stuck/failing electric motor (or maybe this is just how they are) because as soon as it receives power you can hear it trying to actuate something every few seconds until shortly after I remove the key.
[My question to you guys is: what would you do?] This is a street car and I plan on replacing both turbos among many other things within the next months and removing the EVC, but I am left with the option to either attempt to revert to stock, install boost jets, or go with an Electronic Boost Controller.
-Reverting to stock I'm not sure what kind of performance I can expect with the JWT ECU and no boost jets. I know it is tuned for 12-13psi, but without the boost jets and on stock boost control I assume it will see factory boost ~10psi running rich.
-Going with the boost jets I know they are prone to a few issues including boost spiking and early wastegate actuation (or so I've read) AND I wouldn't feel right installing them without an accurate boost gauge. Of course, boost gauges in California are also technically not allowed. I wouldn't mind installing one and removing it for smog but it's quite an expense if I don't plan on ever mounting it.
-Ideally I'd go with the EBC set to 12-13psi and effectively set myself up for future mods while performing the intended job of the JWT boost jets flawlessly and seeing the best performance result overall, but CA regs say no.
In conclusion, the EVC installed has two settings: LOW and HIGH and I have no clue what sort of psi to expect with either other than a ballpark range, so I currently have it set to low and had been getting inconsistent boost and bad turbo noise until I stopped driving it shortly after buying it. However, I assume the ECU is not tuned for this EVC which would enable the previous options, provided no damage has been done I don't know about. I don't know exactly what to expect if I turn the EVC off and drive and do not plan to. I have pictures I planned to attach to this but I don't know forum rules so I'll hold onto them for now.
-I appreciate any advice or opinion shared, Todd
What would you do?
Re: What would you do?
sounds normal. run through the setup for the boost controller to set the values and try it in learning mode and manual mode. instructions are at the bottom of the page. it's meant to constantly be moving the solenoid to sharpen the boost response then probably does a self test/calibration when you turn it off.
https://1jzmerc.com/hks-faq/accessories/hks-evc
after market parts with a CARB exemption are allowed. that's how it passed the smog test.
I dont know why you'd need a boost jet for an electronic boost controller. some gauges require them but that's because they gauge has the wrong face plate on it and it allows manufacturers to use a cheaper gauge.
https://1jzmerc.com/hks-faq/accessories/hks-evc
after market parts with a CARB exemption are allowed. that's how it passed the smog test.
I dont know why you'd need a boost jet for an electronic boost controller. some gauges require them but that's because they gauge has the wrong face plate on it and it allows manufacturers to use a cheaper gauge.
Re: What would you do?
I see, thanks for the info. I don't plan to run this EVC, just looking for an alternate at the moment. The car is in the garage awaiting parts.elecfus wrote:sounds normal. run through the setup for the boost controller to set the values and try it in learning mode and manual mode. instructions are at the bottom of the page. it's meant to constantly be moving the solenoid to sharpen the boost response then probably does a self test/calibration when you turn it off.
https://1jzmerc.com/hks-faq/accessories/hks-evc
after market parts with a CARB exemption are allowed. that's how it passed the smog test.
I dont know why you'd need a boost jet for an electronic boost controller. some gauges require them but that's because they gauge has the wrong face plate on it and it allows manufacturers to use a cheaper gauge.
The boost jets would be in place of an EBC if I don't end up buying an EBC. I'd be buying the boost jets that come with the installed JWT ECU standard. Still, I have no way that I know of to accurately verify the boost levels without installing a boost gauge.
Also as far as the CARB exemption, the manual for this EVC specifically says "Not legal for sale or use in the state of California on any pollution controlled vehicles." However, I did find the CARB exemption for 94 and prior saying the HKS EVC 1-2 is allowed. ??? So if I find an EBC/boost gauge that is CARB exempt I'm good? I was looking at the AEM tru boost EBC but it clearly says not for public road use on the first page of the user manual and has no CARB exemption that I can locate. If it is not technically illegal then my question is answered.
Are there any street legal modern boost controllers or aftermarket boost gauges for the 300zx?
-Todd