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.

 

Have I done something wrong?....

Remap ! Changing the solenoid for a 3 port requires changes to the map which can't be mitigated by just monitoring AFR's. Stop trying to blow your car up and get it mapped fella

 

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.

 

3-port doesn't need the pill. But, as has been said, once you go 3-port it 100% needs remapping IME.

The way a 2-port and 3-port work are totally different and they're not interchangeable.

 

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.

 

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

 

Thank you for the excellent explanation. My car is Newage, I've just fitted a Classic solenoid as that's what I had sat around

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.

 

I doubt that taking the pill out will improve it - probably quite the opposite. But, I'm thinking/talking theoretically.

 

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

 

What he said

 

Impressed its still running with that many mods and no map

 

 

Will need injectors to get most out of your setup.

Has the uppipe cat been removed?

 

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.

 

Stop messing with it? Impossible!

 

Very true. When I bought it in April I was going to leave it stock. Since then I've spent a fortune and a lot of time changing the interior, exterior and now the performance. It keeps me out of the house though

 

Not sure what it is with subaru's but its impossible not to.

 

Have you changed the fuel pump?