Bypassing the the bypass valve solenoid.
- Thread starter MPFab
- Start date
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The M32 Martyr
Just a little added review....
I've been running this mod for a couple hundred miles. Wow! What a difference! This is one of the most noticeable differences in power behavior I've felt in a long time.
This particular boost solenoid nanny gives the ECM too much involvement in how you make boost. Unwanted involvement that is likely another control to keep the driving experience soft and consistent for the average economy consumer with a Stage 0 clutch.
I mean, wouldn't it be horrible if some poor unsuspecting customer pressed the gas pedal and got a buttful of throttle response? That's not what they paid for and they would very likely return it for a Hyundai.
Also noteworthy is the direct relation this solenoid has on shifting, because of the throttle closing between shifts. I've always wondered why this car has such a disconnected feeling even in gear when blip off the throttle. Any other manual I've owned will buck like a Bronco if you do that in the powerband.
Well I'm very pleased with how this bypass bypass (bypass squared if you will) returns my Sonic to a more traditional manual behavior.
This mod will surely spread like wildfire.
Thanks MPFab!!!!
I've been running this mod for a couple hundred miles. Wow! What a difference! This is one of the most noticeable differences in power behavior I've felt in a long time.
This particular boost solenoid nanny gives the ECM too much involvement in how you make boost. Unwanted involvement that is likely another control to keep the driving experience soft and consistent for the average economy consumer with a Stage 0 clutch.
I mean, wouldn't it be horrible if some poor unsuspecting customer pressed the gas pedal and got a buttful of throttle response? That's not what they paid for and they would very likely return it for a Hyundai.
Also noteworthy is the direct relation this solenoid has on shifting, because of the throttle closing between shifts. I've always wondered why this car has such a disconnected feeling even in gear when blip off the throttle. Any other manual I've owned will buck like a Bronco if you do that in the powerband.
Well I'm very pleased with how this bypass bypass (bypass squared if you will) returns my Sonic to a more traditional manual behavior.
This mod will surely spread like wildfire.
Thanks MPFab!!!!
Missionary
New member
Been following this for a bit now, would love to see numbers to support.
xsonicLTZx
New member
This should be sticky-ed some where! Thanks for the write up and for sharing for free instead of charging $49.95 for the incite ;-p
NewZJ
I Don't Know
ftfy
NewZJ
I Don't Know
He is about to release a clutch and flywheel upgrade option, this might be a great way to build up some sales for it by destroying the stock clutches
Edit: please don't think I'm insinuating malintent, he does great work and sells great products. He doesn't want you to hurt your car.
Edit: please don't think I'm insinuating malintent, he does great work and sells great products. He doesn't want you to hurt your car.
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I have already bought my supplies for the project, but.. what is regulating boost at this point? Obviously we still have the waste gate but the blow off gives the last bit of control for how much boost. Are the members who've done it, hitting boost numbers higher than intended or does the cap stay at 22.5? Just want to make sure before people blow head gaskets. Believe me I want to install the setup now I just want to make sure
Quinton Exler
New member
How much would an automatic 1.4 appreciate this mod?
sx sonic
New member
Boost pressure is controlled entirely by the wastegate, it's sole purpose is to modulate boost pressure and shaft speed.
The BPV/BOVs sole purpose is to vent pressure when the throttle is closed.
With out this the boost would suddenly hit a wall that is the throttle plate and try to reverse flow thru the spinning compressor (which may be turning 150k RPM). This is horribly bad for the compressor wheel and bearings.
Now GM may have blurred the line a little bit here but the components still function the same. They just added a little nanny-ing to the BPV. it will bleed off a little extra boost at times to numb power delivery. Much like a super overweight triple sprung flywheel and pressure plate, it's their for the casual motorists that wants to "ride" in a car, not for people that want to "drive" their car.
This mod simply makes the BPV act as it was initially designed for, to vent boost ONLY when the throttle is closed (technically anytime vacuum in the manifold has less authority than the boost psi at the valve). Now when you're WOT the only thing messing with boost is the wastegate.
In fact this is how most turbos are controlled, BPV is hardwired to a manifold vacuum source.
I posted up the gains I found in my 1st post, they're noticeable but not over the top. My initial testing is showing about 8-10hp thru part of the powerband and a smoother torque curve.
Sonic_Boost
New member
NewZJ
I Don't Know
Sonic_Boost
New member
Awesome. Thank you!
Quinton Exler
New member
Probably gonna do this to my automatic, will this fix the issue of boosting 15-20lbs just because I've held the peddle slightly down over a period of time... then the car says "I need more boost to do that" and goes 20lbs of boost at like 3k rpm?
Maddmatts
Member
I had no idea there was anything like that controlling the BPV. Considering all of my problems with underboost trouble codes, I wouldn't be surprised if that solenoid was the problem all this time. It's the only thing that hasn't been replaced.
I'll have to try this when the weather warms up on the weekend.
It'll be as happy with it as without it. The auto has a bit more headroom than the manual + older OEM clutch. I don't think BNR has found it's limit yet on their Cruze test-mule.
I'll have to try this when the weather warms up on the weekend.
It'll be as happy with it as without it. The auto has a bit more headroom than the manual + older OEM clutch. I don't think BNR has found it's limit yet on their Cruze test-mule.
Quinton Exler
New member
Underboost? If I hold my peddle half way down and let my car gradually build boost over a slow RPM gain I will hold 30lbs of boost for a good 5 seconds lol... I was wondering if it might kill my over boost... Because Trifecta never could see my over boost when I logged it, I even took a video of it. I just never can drive my car half peddle pretty much...
sonichead94
New member
just did mines and you can definitely feel the difference. i would usually only see 19-20psi. now i see 22psi pretty steady. The power feels much more smoother. Mpfab...... you have done a good deed my friend