manual boost controller
07-30-2011, 10:42 AM
#1
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Join Date: 04-30-2006
Location: Maryland Heights, MO
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manual boost controller
So I installed this...
My set up came from Hahn maxing out at 8lbs boost. I added this boost controller this morning and can't get it dialed in to 12lbs. The adjuster has "clicks".
It goes from 10lbs on one click to 14-15 on the next. Peaking at 17.
I really don't wanna run over 12lbs since the 2.4 tends to "float" without other work being done that I'm not ready for, valve springs etc...
Suggestions?
My set up came from Hahn maxing out at 8lbs boost. I added this boost controller this morning and can't get it dialed in to 12lbs. The adjuster has "clicks".
It goes from 10lbs on one click to 14-15 on the next. Peaking at 17.
I really don't wanna run over 12lbs since the 2.4 tends to "float" without other work being done that I'm not ready for, valve springs etc...
Suggestions?
08-01-2011, 08:07 AM
#2
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Join Date: 10-02-2005
Location: VA
Posts: 1,245
Mike,
1. That looks like one of those cheap eBay controllers. Do you really want to trust the reliability of your engine to that??
2. If you raise the boost, you had better have your tuner right there to ensure that knock doesn't happen. It's likely!
3. With what you've got going, valve springs are the least of your concerns unless you're revving the heck out of the motor.
Do it right unless a replacement engine is in your budget.
Good luck!
1. That looks like one of those cheap eBay controllers. Do you really want to trust the reliability of your engine to that??
2. If you raise the boost, you had better have your tuner right there to ensure that knock doesn't happen. It's likely!
3. With what you've got going, valve springs are the least of your concerns unless you're revving the heck out of the motor.
Do it right unless a replacement engine is in your budget.
Good luck!
08-01-2011, 04:43 PM
#3
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Join Date: 04-30-2006
Location: Maryland Heights, MO
Posts: 9,149
always a ray of sunshine Joe...
I've been told by many that boosting a 2.4 past 12lbs can cause the valves to float, so that's the reason for the valve springs. I figured If I'm doing that, easy enough to switch out the cams at the same time.
I'm watch the boost very carefully and have a call into my tuner. For now its working fine. It's not like I'm out racing.
and what do you mean by
I've been told by many that boosting a 2.4 past 12lbs can cause the valves to float, so that's the reason for the valve springs. I figured If I'm doing that, easy enough to switch out the cams at the same time.
I'm watch the boost very carefully and have a call into my tuner. For now its working fine. It's not like I'm out racing.
and what do you mean by
With what you've got going, valve springs are the least of your concerns unless you're revving the heck out of the motor.
08-01-2011, 08:09 PM
#4
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Join Date: 03-04-2010
Location: SE Wisconsin
Posts: 458
It sounds like you're going to lean it out too much going from 8-12lbs. Not worth it. You don't have to be out racing in order to blow your engine. I have read the same thing on the 12psi/valve float too. The springs will surely allow you to boost more, but I would be cautious in more boost unless you tune along the way.
08-05-2011, 03:33 PM
#6
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Join Date: 10-02-2005
Location: VA
Posts: 1,245
"always a ray of sunshine Joe..." 
OK, Mike, here's your ray of sunshine for today.... That red controller looks awesome to match your car!!
Was just trying to help with good advice, man!
Back to reality....
More boost will create more intake heat plus higher dynamic compression, both of which make an engine more prone to knock. Knock is your enemy. It will destroy an engine!
I see two expressions in this thread that make me cringe!
"I've been told by many...." and "I have read ..."
Where are you guys getting this info from?
Personally, I've been running over 12 PSI boost and revving to 7,200 for over three years now. I've tuned Cobalt LSJs to over 21 PSI and LNFs to over 25 PSI running high RPMs without issue. All these EcoTecs use the same exact valve springs! (source = GM) I think these myths get started more by vendors selling valve springs than reality. Now go for really high revs and / or boost, then yes.
Why would he "lean it out too much going from 8-12lbs."? The MAF will read the higher air mass with more boost.
Just trying to help here and deal with facts.
Disclaimer: I didn't graduate from charm school!
OK, Mike, here's your ray of sunshine for today.... That red controller looks awesome to match your car!!
Was just trying to help with good advice, man!Back to reality....
More boost will create more intake heat plus higher dynamic compression, both of which make an engine more prone to knock. Knock is your enemy. It will destroy an engine!
I see two expressions in this thread that make me cringe!
"I've been told by many...." and "I have read ..."
Where are you guys getting this info from?
Personally, I've been running over 12 PSI boost and revving to 7,200 for over three years now. I've tuned Cobalt LSJs to over 21 PSI and LNFs to over 25 PSI running high RPMs without issue. All these EcoTecs use the same exact valve springs! (source = GM) I think these myths get started more by vendors selling valve springs than reality. Now go for really high revs and / or boost, then yes.
Why would he "lean it out too much going from 8-12lbs."? The MAF will read the higher air mass with more boost.
Just trying to help here and deal with facts.
Disclaimer: I didn't graduate from charm school!
08-05-2011, 08:40 PM
#7
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Join Date: 03-04-2010
Location: SE Wisconsin
Posts: 458
Matt @ ZZP from cobaltss.net:
"LE5 cams have more lift than LSJ cams. This causes valve control issues at a lower psi and/or RPM. We couldn't get past 315whp on the stock springs. At 12psi/7200 RPM, the valve float was so bad that it sounded like a rev limiter. With 78lb springs installed, we dyno'd up to 15psi/7800 RPM and 356whp without issue."
"Stock valve springs are only around 50-55lbs on the seat. For ease of explanation, if there is 1 square inch of surface area where boost is pushing down on the intake valve as it tries to close and 12psi in the intake manifold, then you have effectively dropped your seat pressure down to 38-43lbs and the valve can launch off the rocker at peak lift or bounce off the seat as it closes at high RPMs. The numbers aren't exact because there is always vacuum or pressure numbers below the intake valve which would need to be considered, and I haven't actually measured how much surface area of the valve is subject to manifold air pressure trying to push it open. It is merely meant to explain that boost does have an affect on valvespring performance."
http://www.cobaltss.net/forums/2-4l-...k-here-194930/
Joe your argument is made in this thread as well.
"LE5 cams have more lift than LSJ cams. This causes valve control issues at a lower psi and/or RPM. We couldn't get past 315whp on the stock springs. At 12psi/7200 RPM, the valve float was so bad that it sounded like a rev limiter. With 78lb springs installed, we dyno'd up to 15psi/7800 RPM and 356whp without issue."
"Stock valve springs are only around 50-55lbs on the seat. For ease of explanation, if there is 1 square inch of surface area where boost is pushing down on the intake valve as it tries to close and 12psi in the intake manifold, then you have effectively dropped your seat pressure down to 38-43lbs and the valve can launch off the rocker at peak lift or bounce off the seat as it closes at high RPMs. The numbers aren't exact because there is always vacuum or pressure numbers below the intake valve which would need to be considered, and I haven't actually measured how much surface area of the valve is subject to manifold air pressure trying to push it open. It is merely meant to explain that boost does have an affect on valvespring performance."
http://www.cobaltss.net/forums/2-4l-...k-here-194930/
Joe your argument is made in this thread as well.
08-05-2011, 09:05 PM
#8
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Thread Starter
Join Date: 04-30-2006
Location: Maryland Heights, MO
Posts: 9,149
"always a ray of sunshine Joe..."
OK, Mike, here's your ray of sunshine for today.... That red controller looks awesome to match your car!! Was just trying to help with good advice, man!
Back to reality....
More boost will create more intake heat plus higher dynamic compression, both of which make an engine more prone to knock. Knock is your enemy. It will destroy an engine!
I see two expressions in this thread that make me cringe!
"I've been told by many...." and "I have read ..."
Where are you guys getting this info from?
Personally, I've been running over 12 PSI boost and revving to 7,200 for over three years now. I've tuned Cobalt LSJs to over 21 PSI and LNFs to over 25 PSI running high RPMs without issue. All these EcoTecs use the same exact valve springs! (source = GM) I think these myths get started more by vendors selling valve springs than reality. Now go for really high revs and / or boost, then yes.
Why would he "lean it out too much going from 8-12lbs."? The MAF will read the higher air mass with more boost.
Just trying to help here and deal with facts.
Disclaimer: I didn't graduate from charm school!
OK, Mike, here's your ray of sunshine for today.... That red controller looks awesome to match your car!!
Was just trying to help with good advice, man!Back to reality....
More boost will create more intake heat plus higher dynamic compression, both of which make an engine more prone to knock. Knock is your enemy. It will destroy an engine!
I see two expressions in this thread that make me cringe!
"I've been told by many...." and "I have read ..."
Where are you guys getting this info from?
Personally, I've been running over 12 PSI boost and revving to 7,200 for over three years now. I've tuned Cobalt LSJs to over 21 PSI and LNFs to over 25 PSI running high RPMs without issue. All these EcoTecs use the same exact valve springs! (source = GM) I think these myths get started more by vendors selling valve springs than reality. Now go for really high revs and / or boost, then yes.
Why would he "lean it out too much going from 8-12lbs."? The MAF will read the higher air mass with more boost.
Just trying to help here and deal with facts.
Disclaimer: I didn't graduate from charm school!
My tuner is the one who when he "fixed" the mess Bill Hahn left me, is the one who told me any boost controller would do the job. (Of couse now he's changing his tune! AND not returning any of my phone calls/texts/PM's/posts/emails!) You know me well enough to know that I asked him when he was doing the tune.
Him, Hahn, and others told me the valves could float. So the need for new springs.
The lean comments other made I don't get. I've got bigger injectors and my a/f is staying in the right range according to my wide-band.
I do have a better boost controller on the way.
08-05-2011, 09:23 PM
#9
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Join Date: 03-04-2010
Location: SE Wisconsin
Posts: 458
It sounds like you're going to lean it out too much going from 8-12lbs. Not worth it. You don't have to be out racing in order to blow your engine. I have read the same thing on the 12psi/valve float too. The springs will surely allow you to boost more, but I would be cautious in more boost unless you tune along the way.
...Though my only rational for this would be my MAF table would be lean at higher air flows according to my graph because I never smoothed my graph for an airflow other than what I can achieve. Since no tuning can be done at higher than normal MAF readings, leaning out could occur with higher boost especially if you're unaware if the injectors can keep up, or the table is not manually stepped, no?
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