Boost spike following 3 port solenoid install
21 September 2013, 10:44 PM
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Boost spike following 3 port solenoid install
I'm after a bit of advice please. I have done a search but I haven't found the answer yet.
I have a 2001 WRX Bug with the following mods:
Front mount intercooler
VF22 turbo
HKS SSQ BOV (sorry)
2.5" stainless system with Prodrive sports cat and Afterburner Vortex back box
De-catted up pipe
RCM intake pipe with large K&N filter
I haven't mapped it yet but I do have a wideband gauge installed and the fuelling is 14.7:1 on light throttle and idle and about 9.8:1 under wide open throttle. Medium acceleration hovers around 12:1.
Anyway all was fine and it was running at a steady 1.1 bar on boost with no spiking or boost loss. I have just installed a three port boost solenoid (to replace the stock two port one) and it's now spiking. Under acceleration it boosts to just over 0.5 bar, holds for a split second then boosts up to 1.5 bar. It then, within seconds, drops to 1 bar and holds there with no issues.
I piped the boost solenoid up as follows:
Top outlet goes to the turbo housing with the restrictor pill
The side outlet goes to the wastegate
The bottom outlet goes to the intake pipe.
Have I done something wrong? (Other than a BOV and not yet remapped)
Thanks in advance.
I have a 2001 WRX Bug with the following mods:
Front mount intercooler
VF22 turbo
HKS SSQ BOV (sorry)
2.5" stainless system with Prodrive sports cat and Afterburner Vortex back box
De-catted up pipe
RCM intake pipe with large K&N filter
I haven't mapped it yet but I do have a wideband gauge installed and the fuelling is 14.7:1 on light throttle and idle and about 9.8:1 under wide open throttle. Medium acceleration hovers around 12:1.
Anyway all was fine and it was running at a steady 1.1 bar on boost with no spiking or boost loss. I have just installed a three port boost solenoid (to replace the stock two port one) and it's now spiking. Under acceleration it boosts to just over 0.5 bar, holds for a split second then boosts up to 1.5 bar. It then, within seconds, drops to 1 bar and holds there with no issues.
I piped the boost solenoid up as follows:
Top outlet goes to the turbo housing with the restrictor pill
The side outlet goes to the wastegate
The bottom outlet goes to the intake pipe.
Have I done something wrong? (Other than a BOV and not yet remapped)
Thanks in advance.
21 September 2013, 10:59 PM
#3
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Cheers. I wasn't too sure how much difference the 3 port would make but I wasn't expecting the spike, even without a remap. I am going to sort the map next anyway, I'm just fitting everything first. The car only does, on average, 5 miles per week. I only take it out after I've worked on it as I don't really want to take it far until it's been mapped. I really just wanted to make sure i'd piped it up right and the pill was in the correct pipe.
21 September 2013, 11:17 PM
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Thank you. So before I get it mapped I should remove the pill then? The car I got it off actually had the pill in it which is why I left it in. The solenoid is off a Classic STi.
21 September 2013, 11:28 PM
#6
My experience is with the newage, so I wouldn't like to "pronounce" definitively for a classic - best talk to your mapper.
With a 2-port, there's a pipe from the compressor housing to the wastegate. The pill restricts the rate at which the pressure is applied to the wastegate, allowing boost to build quickly. The 2-port then bleeds pressure from that system, under ECU control, to limit the absolute boost you can achieve. Always seemed like an uncomfortable mix of mechanical vs. electronic control.
With the 3-port, the pressure supplied to the wastegate is totally dependent on ECU control - the compressor takeoff is fed to the 3-port, and the ECU determines how much is fed to the wastegate and how much is vented/recirculated.
The ability to control that *might* be dependent on the capabilities of the ECU.
So, check with your mapper as I might be talking bill hooks
With a 2-port, there's a pipe from the compressor housing to the wastegate. The pill restricts the rate at which the pressure is applied to the wastegate, allowing boost to build quickly. The 2-port then bleeds pressure from that system, under ECU control, to limit the absolute boost you can achieve. Always seemed like an uncomfortable mix of mechanical vs. electronic control.
With the 3-port, the pressure supplied to the wastegate is totally dependent on ECU control - the compressor takeoff is fed to the 3-port, and the ECU determines how much is fed to the wastegate and how much is vented/recirculated.
The ability to control that *might* be dependent on the capabilities of the ECU.
So, check with your mapper as I might be talking bill hooks
21 September 2013, 11:42 PM
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My experience is with the newage, so I wouldn't like to "pronounce" definitively for a classic - best talk to your mapper.
With a 2-port, there's a pipe from the compressor housing to the wastegate. The pill restricts the rate at which the pressure is applied to the wastegate, allowing boost to build quickly. The 2-port then bleeds pressure from that system, under ECU control, to limit the absolute boost you can achieve. Always seemed like an uncomfortable mix of mechanical vs. electronic control.
With the 3-port, the pressure supplied to the wastegate is totally dependent on ECU control - the compressor takeoff is fed to the 3-port, and the ECU determines how much is fed to the wastegate and how much is vented/recirculated.
The ability to control that *might* be dependent on the capabilities of the ECU.
So, check with your mapper as I might be talking bill hooks
With a 2-port, there's a pipe from the compressor housing to the wastegate. The pill restricts the rate at which the pressure is applied to the wastegate, allowing boost to build quickly. The 2-port then bleeds pressure from that system, under ECU control, to limit the absolute boost you can achieve. Always seemed like an uncomfortable mix of mechanical vs. electronic control.
With the 3-port, the pressure supplied to the wastegate is totally dependent on ECU control - the compressor takeoff is fed to the 3-port, and the ECU determines how much is fed to the wastegate and how much is vented/recirculated.
The ability to control that *might* be dependent on the capabilities of the ECU.
So, check with your mapper as I might be talking bill hooks
I will take the pill out tomorrow and see if that stops the spike. I will then sort out the mapping although I may just fit my 550's first so I only need to map it once.
Thank you for all your help.
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21 September 2013, 11:49 PM
#9
Blimey the DENSO ECU is having a hard time 
No point messing about with the restrictor pill, fit the larger injectors and then get it mapped
The ECU falls over itself when you fit a 3-port as in post 4
Shaun
No point messing about with the restrictor pill, fit the larger injectors and then get it mapped
The ECU falls over itself when you fit a 3-port as in post 4
Shaun
22 September 2013, 11:10 AM
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Yes, the up pipe cat has been removed. The only cat left is the Prodrive sports cat in the front pipe. Since doing all the mods the car has probably done about 20 miles and most of that has been off boost. I'll hopefully be fitting my injectors in the next two weeks and then I will get it mapped and then hopefully stop messing with it.
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