Just wondering if it was normal for it to be easier to reach boost in the higher gears with the mp62 on the ecotec? I really have to floor it get boost in 1st gear. 2nd is easier and third+ plus I barely have to try. This is my 1st boosted vehicle just wondering if my car is acting normal.
Same as mine...kinda..
I see boost at about 1/4 throttle.....rpm's arent a factor
hey guys...this is gonna be different with every car. it all depends on head port size and TB size and all that. and with a blower, you need to factor in that the faster the blower spins the quicker it will make boost. I can drive all day without seeing boost, or i can see boost in ever gear. its all about throttle. I cruised to work today at 85 MPH and never saw boost once. then i got on it out of the parking lot going to work, and had 11 PSI before i was in second gear....so it all just depends. I am willing to bet that both of your cars are just fine!
EvoFire wrote:hey guys...this is gonna be different with every car. it all depends on head port size and TB size and all that. and with a blower, you need to factor in that the faster the blower spins the quicker it will make boost. I can drive all day without seeing boost, or i can see boost in ever gear. its all about throttle. I cruised to work today at 85 MPH and never saw boost once. then i got on it out of the parking lot going to work, and had 11 PSI before i was in second gear....so it all just depends. I am willing to bet that both of your cars are just fine!
I dont think there was anything wrong with mine....was just relating what ive experienced.
I drive daily without hitting boost all that often...but usually after 1/4 throttle I start getting into boost.
Just double checking if my car is normal and I don't have a boost leak or something.
as you go into higher gears, your adding more load to the engine. more engine load equals more throttle. more throttle equals more air. more air equals more boost.
Your question is relative to RPM increase. Load is less of a factor on the supercharger because the supercharger flows the exact same amount of air per revolution regardless of what your load is. Load (vacuum as an indicator of load) does however affect the position of the bypass valve which regulates airflow past the rotors of the SCer. As vacuum increases toward atmospheric pressure the bypass valves butterfly plate begins to close in relation to the vacuum signal. The reason it is easier (in other and more accurate wording "faster") to hit max boost is typically because your RPMs are already higher every time you switch gears. Yes, the RPM drops in between shifts but the bottom of each gear is slightly higher in RPM each time. Essentially the super charger is flowing more air every time you step up a gear because it is spinning faster at the bottom of each gear (if the bypass valve was always closed this would be pretty easy to see happening). This should be pretty marginal though and barely noticeable under regulated bypass adjustments via vacuum increases/decreases as you go through a typical load range. Now if there is a significant quickness to maximum boost levels the bypass valve would be your first culprit to take a look at (possible vacuum leak). Your SCer should be hitting boost pretty well immediately upon WOT (thats the perk to SCers, instant boost no matter what haha).
ASE Master Certified Automotive Technician
It's really hard for me to hit boost in first gear. I can hear it whining but as soon as its at 0 vacuum my gear is over. I accidentally bounced off the rev limiter the other day trying it.
Have you tried wot.....
You should hit boost fast...but if your just accelerating normal you might not hit boost but just hear the charger whine a bit.
I can pin it in first and you have instant full boost but the gear is over very fast.
I make it through 1st so fast with the tires spinning that I never see boost because the gauge just cant react fast enough. Its making boost, HP Tuners says so, my boost gauge needle just cant move fast enough.
1994 Saturn SL2 Home Coming Edition: backup car
2002 Chevy Cavalier LS Sport Coupe: In a Junk Yard
1995 Mazda Miata R-package Class=STR
Sponsored by:
Kronos Performance
WPI Class of '12 Mechanical Engineering
WPI SAE Risk and Sustainability Management Officer
Yeah it's def faster I think the needle may be too slow. I replaced my vac line off the bypass control and swapped out the crappy ribbed temporary intake for actual tubing today and it seems like my boost picked up a bit. If I even try wot I just move through my 1st gear in like 2 seconds.
Strange I never had a gauge lag in any of my cars or with the SCer. Are you running a mechanical or electric gauge?
ASE Master Certified Automotive Technician
Mine's electric. It takes a good half second to go from no boost to 14 psi.
1994 Saturn SL2 Home Coming Edition: backup car
2002 Chevy Cavalier LS Sport Coupe: In a Junk Yard
1995 Mazda Miata R-package Class=STR
Sponsored by:
Kronos Performance
WPI Class of '12 Mechanical Engineering
WPI SAE Risk and Sustainability Management Officer
my logging program shows instant boost....but my gauge climbs liek i said before from 0 to whatever its at when i let off....it climbs in like .2 or .3 incriments.
Yah mines a mechanical and its instant.
One of the reasons I went with mechanical over the electric. The electric has a smoother operation but is laggy.
Philly D wrote:Yah mines a mechanical and its instant.
One of the reasons I went with mechanical over the electric. The electric has a smoother operation but is laggy.
Same here. I'm a fan of mechanical Boost/Vac gauges, Typically far more accurate in cases like this. The AEM TRU Boost gauge (electric) has zero lag though and that's what I have been running for several years now. I still prefer the mechanical even over the Tru Boost for the simple fact it's much easier to see the progression of pressure with a needle but in all AEM did a pretty good job.
ASE Master Certified Automotive Technician
My autometer jumps immediately, now if only it went as high as some of you that are at sea level lol
check your vac line going to your gauge. something isnt right, you should be seeing boost instantly. I can blow the tires off in 1st gear in my car and it will show 10 psi all day long...
01' Z24 5 speed
422whp/400wtq
T4 Turbocharged
Built LD9
HP Tuners
Saw a video online and the guy was making boost in neutral. I can't even do this. I'm pretty sure I have a boost leak. I'm going to replace the gauge line tonight.
ecotecpower wrote:My autometer jumps immediately, now if only it went as high as some of you that are at sea level lol
This... except the sea level part. mine jumps to 16# rather quickly
replaced the boost gauge line today with some rubber hose (no stupid plastic crap anymore). Seeing a little more boost at the gauge now, but still no boost in first or neutral. In 1st it gets up to 0 and just falls down. It higher gears I can get 8 psi steady. Do you guys think it could be my boost bypass? I read you can plug the hose that is open to the air to test. I'm going to try that and see if it makes a difference.
