Boost controller - to build boost faster

[cycleofabuse]

Hi all,
I've searched and searched but couldn't quite find what I was after.
Yesterday I bought a Liberty MY07 spec B. Great car, but boost builds up very slowly (compared to my S15 which has a greddy profec spec b boost controller).
I keep reading that adding a boost controller is a bad idea. I'm keen to put the latest greddy one on the Liberty. Not to raise the peak boost, but to be able to: build boost faster at lower revs, it'll also act as a boost gauge and it will graph the boost pressure over the rev range.

My S15 is so responsive and boosts rapidly all thanks to the boost controller. Surely the Liberty would benefit from the same treatment, am I missing the downside?

Thanks in advance.

[jaydece]

Hi all,
I've searched and searched but couldn't quite find what I was after.
Yesterday I bought a Liberty MY07 spec B. Great car, but boost builds up very slowly (compared to my S15 which has a greddy profec spec b boost controller).
I keep reading that adding a boost controller is a bad idea. I'm keen to put the latest greddy one on the Liberty. Not to raise the peak boost, but to be able to: build boost faster at lower revs, it'll also act as a boost gauge and it will graph the boost pressure over the rev range.

My S15 is so responsive and boosts rapidly all thanks to the boost controller. Surely the Liberty would benefit from the same treatment, am I missing the downside?

Thanks in advance.

a custom tune will fix the problems you mention above...running the stock tune? stock car?

if you have simple mods? a custom tune will go a long way...

The ecu parameters in the lib are pretty good just shit tables in stock form....unless you have a massive build with lots of custom stuff and want massive boost? then yeah boost controller...

[cycleofabuse]

Yes, stock tune, stock car.
So the retuned ECU will hold the wastegate shut for longer? That's pretty cool.
Better start researching tuners then...
Thanks!

[Manaz]

The ECU controls boost on a Liberty. It's generally pretty good once tuned properly (it's rare to see people using third party ECUs on Liberties), though there are a few people (myself included, mine isn't fitted yet) who have opted for the Pierburg 3-port boost control solenoid (it gets driven by the ECU, but does require different tuning) for more accurate boost control (rather than faster boost).

Even with the stock tune, you should see a difference just by switching between I, S and S# modes with the SI-Drive...

[blacktop™]

Aftermarket electronic boost controllers (like your profec b) are also perfectly fine to use with our cars as well.

[Manaz]

Aftermarket electronic boost controllers (like your profec b) are also perfectly fine to use with our cars as well.

Sure - but there's really not much benefit in doing so, and they can confuse the standard ECU.

[blacktop™]

Aftermarket electronic boost controllers (like your profec b) are also perfectly fine to use with our cars as well.

Sure - but there's really not much benefit in doing so, and they can confuse the standard ECU.

Not much benefit apart from better boost control...

My evc 5 works perfectly and also doubles as a boost gauge like the OP has mentioned.

You hear problems all the time on here of people having problems with different types of 3 port solenoids. Take your car to a good tuner and your ecu will not get confused with anything.

[senator]

Aftermarket electronic boost controllers (like your profec b) are also perfectly fine to use with our cars as well.

Sure - but there's really not much benefit in doing so, and they can confuse the standard ECU.

Not much benefit apart from better boost control...

My evc 5 works perfectly and also doubles as a boost gauge like the OP has mentioned.

You hear problems all the time on here of people having problems with different types of 3 port solenoids. Take your car to a good tuner and your ecu will not get confused with anything.

+1 regarding a good tuner

That’s the benefit of the EVC……. No old school solenoid, precise boost control thanks to a servo motor, that works much quicker than a solenoid and also far more accurate….. most people get turned off the HKS EVC due to price, not understanding the true benefit.

[KiDo_Tuning]

Actually there is a publicly undefined table for cylinder fill rate based on throttle position, aftermarket boost controller is trying to fill the engines lungs with full boost on partial throttle, ECU pulls back throttle to restrain the boost and you end up with a massive surge of boost as it finally snaps from sfa throttle to full throttle.

Aftermarket external controller has no closed loop feedback to disable boost if an engine issue occurs nor does it have temp or barometer compensation

[west_minist]

Actually there is a publicly undefined table for cylinder fill rate based on throttle position, aftermarket boost controller is trying to fill the engines lungs with full boost on partial throttle, ECU pulls back throttle to restrain the boost and you end up with a massive surge of boost as it finally snaps from sfa throttle to full throttle.

Aftermarket external controller has no closed loop feedback to disable boost if an engine issue occurs nor does it have temp or barometer compensation

It still amazes me why one would need it outside of racing.

Because a Subaru or EVO or maybe a mazda does not boost, does not mean boost issues. Its possible the ECU disable boost and persons much understand that!

Good explanation Matt!

[<GB>]

I put my evc on due to my tuner saying I needed one!! car was making around 250awkw on the stock boost controller. now im thinking about going to an after market boost controller and removing the evc

[cycleofabuse]

Actually there is a publicly undefined table for cylinder fill rate based on throttle position, aftermarket boost controller is trying to fill the engines lungs with full boost on partial throttle, ECU pulls back throttle to restrain the boost and you end up with a massive surge of boost as it finally snaps from sfa throttle to full throttle.

Aftermarket external controller has no closed loop feedback to disable boost if an engine issue occurs nor does it have temp or barometer compensation

Makes sense, certainly sounds like it's best left to the ECU to control then. Aftermarket controller worked fine on my S15, but in that case the ECU wasn't controlling/limiting the boost. It's just a simple wastegate actuator.

[cycleofabuse]

Just thought I'd update my own thread. I ended up getting a Kido tune. My goal of having boost build earlier and stronger has definitely been achieved. Way more torque down low (on and off boost), much smoother acceleration. So much more fun to drive now. If you're considering a Kido tune, I would highly recommend it.

[shav]

Just thought I'd update my own thread. I ended up getting a Kido tune. My goal of having boost build earlier and stronger has definitely been achieved. Way more torque down low (on and off boost), much smoother acceleration. So much more fun to drive now. If you're considering a Kido tune, I would highly recommend it.

Nice work Dave. I had no doubt after reading this thread, that a tune would sort out your concerns. The libs are a awesome machine and with the right tune and tuner, a lot can be done without massive expense.

What's next on your agenda?

[cycleofabuse]

Zero plans at this point. My last car has pretty modified and I always thought it was a cop magnet (despite not really having much trouble with the police). So I'm considering keeping this ride pretty standard. Pretty nice to drive just the way it is. Probably not what most of you guys want to hear!