boost gauge readings - is this correct?

[gnailuh]

newbie here, installed my boost gauge, very interesting!!! now i know why people say the factory meter sucks... can you guys tell me if my reading are correct for a mostly stock engine?

only mods i have are: K&N FIPK filter & the BCS restrictor removal. i installed an autometer sport-comp mechanical boost gauge. boost tapped between intake manifold and the fuel pressure solenoid. here's what i noticed (questions follow each section)

suprise #1, while idling, gauge reads vac (about 22-24 in-Hg), only when RPM reaches 3000 or so before boost actually start to come in. this is correct?

#2, during testing, i pushed first and second to about 5K rpm, at this rpm, psi reached about 9-11, and the slightest left off on the gas, or just the cease of acceleration show the boost drop off instantly... should be the way it is?

#3, in 3rd gear, boost seems to come on real fast and strong. hit as high as 12.5 psi, then started to drop off even if i push after 5K rpm. is this correct? this is because the wastegate opened or because the crappy bov opened? i'm guessing wastegate since i can clearly hear the bov when i shut the throttle.

#4, when i'm going up a nice steady hill and keep the car in 3rd, even at 2K rpm the boost is coming on strong... what dictates a strong boost? as long as the engine is straining?

BIG Question... i'm doing this to get a base line before i install a manual boost controller.
#a: will i see higher boost with everything as is?
#b: i should get faster spooling right? that's what i'm really hoping for, more than higher boost...
#c: can the bov handle much more than the current 12.5psi? if it can't handle that psi, how can i tell? can i hear the bov leaking?
#d: with a mbc, will it keep the boost at max for longer periods?

this is really fun and you guys been awesome in answering my other dumb questions... please answer ALL these and in great detail!!! i LOVE details...

thanks a bunch.

 

[5150DSM]

#1 Yes
#2 Yes
#3 Boost spike from BCS removal? Maybe leaking BOV?
#4 Boost is generated from the heat(mostly)in your exhaust gas; hence, the more load(not neccessarily rpm's) your engine is under, the more heat generated in the exhaust flow=more boost



Your stock BOV won't handle much more, in fact, it is probably leaking slightly at 12.5. Switch to a 1G BOV, they are cheap(see junkyard) and hold boost much better, plus, they can be easily modified to hold even more boost.(20+ psi)
With a good ball and spring MBC (JoeP, Hallman)you should be able to set your boost at a fairly constant level(1-2psi fluctuation)Thus you will be able to turn up your boost and have more power(theoretically)than your current set up. If you want to spool faster, try a hard UICP and/or a hard intake pipe; also any porting of the exhaust manifold and/or O2 housing will help with spool time. Hope this helps, good luck.

 

[gnailuh]

I read that the JoeP mbc has two balls... what's that all about? how is that better? also, hallman has a new Pro kit that has a ceramic ball, that's suppose to be lighter so it move faster... are these all valid points for a mbc?

should i just stick to the hallman es (essencial) as they call it, for $50 bucks and stick with that?

i was told by someone that the stock intake pipe, the plastic one with the ruffles, help to damp vibration. so changing to a rigid solid metal pipe could shake things loose... what do you think?

one last thing: the trick to cut short the bov dump tube... is it REALLY helpful? and does it make things much loader? i don't want my car to be too loud when the bov dumps...

thanks.

 

[5150DSM]

The dual ball design allows for tighter, more accurate control and precision adjustment. (1/8 turn = 1psi)(roughly) So yes, it is good, it is a proven design that can hold high(30+psi)boost pressures, all day long. Ceramic ball...? I'm not an engineer and Hallman's controller is also a proven design; however, I'm not sure that the weight of the ball bearings would affect the operation of the boost controller. Maybe someone with more understanding of the dynamics chime in on this. BOV dump tube...? If your BOV is recirculated then it will be relatively quiet regardless of dump tube length but cutting it WILL make the dump louder. Here check out this article: http://www.tgilmore.com/talon/dumptube.html
Hard intake pipe=dangerous vibration=bullshit. Just clamp everything down tight and if you want added security, bolt a bracket over the pipe using the existing mount points. Good Luck!

 

[mygsx2120]

i dont mean too bring such an old thread to life, but i found it while i was searching and i think i stumbled across some misinformation. this thread states boost is generated from heat. this is not the case at all, is it. i'm just a noob, so could someone please clarify. thanks

 

[silver bullit]

i dont mean too bring such an old thread to life, but i found it while i was searching and i think i stumbled across some misinformation. this thread states boost is generated from heat. this is not the case at all, is it. i'm just a noob, so could someone please clarify. thanks

No, you are wrong boost. Is created by the turbo which is being driven by hot exhaust gases.

 

[silver bullit]

newbie here, installed my boost gauge, very interesting!!! now i know why people say the factory meter sucks... can you guys tell me if my reading are correct for a mostly stock engine?

only mods i have are: K&N FIPK filter & the BCS restrictor removal. i installed an autometer sport-comp mechanical boost gauge. boost tapped between intake manifold and the fuel pressure solenoid. here's what i noticed (questions follow each section)

suprise #1, while idling, gauge reads vac (about 22-24 in-Hg), only when RPM reaches 3000 or so before boost actually start to come in. this is correct?

#2, during testing, i pushed first and second to about 5K rpm, at this rpm, psi reached about 9-11, and the slightest left off on the gas, or just the cease of acceleration show the boost drop off instantly... should be the way it is?

#3, in 3rd gear, boost seems to come on real fast and strong. hit as high as 12.5 psi, then started to drop off even if i push after 5K rpm. is this correct? this is because the wastegate opened or because the crappy bov opened? i'm guessing wastegate since i can clearly hear the bov when i shut the throttle.

#4, when i'm going up a nice steady hill and keep the car in 3rd, even at 2K rpm the boost is coming on strong... what dictates a strong boost? as long as the engine is straining?

BIG Question... i'm doing this to get a base line before i install a manual boost controller.
#a: will i see higher boost with everything as is?
#b: i should get faster spooling right? that's what i'm really hoping for, more than higher boost...
#c: can the bov handle much more than the current 12.5psi? if it can't handle that psi, how can i tell? can i hear the bov leaking?
#d: with a mbc, will it keep the boost at max for longer periods?

this is really fun and you guys been awesome in answering my other dumb questions... please answer ALL these and in great detail!!! i LOVE details...

thanks a bunch.

1. Yes, 14b reaches max boost at 3k and at a stop that is normal to.
2. Normal max boost of a 14b stock ends at 5-6k.
3 Normal, but if your coasting in 3rd at 60 it will build max boost cause your at the max for 2nd.
4. Going uphill puts a load on the motor, thus the engine revs up and goes depending on your foot on the gas.
5. a.Yes if you turn the boost up.
b. Faster spool, port the head and turbo, or buy a diferent turbo but, any increase with the boost controller and you will feel it when it kick in.
c. Stock metal bov(1g) can handle 16psi or 16+ if you modify it. The 2g plastic is a waste.
d. It will keep it selected at what you set it at. Every turbo has a period where it builds boost reaches its max boost and starts to fade off.

All of this could have been answered if you used the search botton.

 

[jking29]

1. Yes, 14b reaches max boost at 3k and at a stop that is normal to.
2. Normal max boost of a 14b stock ends at 5-6k.
3 Normal, but if your coasting in 3rd at 60 it will build max boost cause your at the max for 2nd.
4. Going uphill puts a load on the motor, thus the engine revs up and goes depending on your foot on the gas.
5. a.Yes if you turn the boost up.
b. Faster spool, port the head and turbo, or buy a diferent turbo but, any increase with the boost controller and you will feel it when it kick in.
c. Stock metal bov(1g) can handle 16psi or 16+ if you modify it. The 2g plastic is a waste.
d. It will keep it selected at what you set it at. Every turbo has a period where it builds boost reaches its max boost and starts to fade off.

All of this could have been answered if you used the search botton.

He doesn't have a 14b, he has a t25. It will not do much more than the 12.5 that its doing right now without blowing hot air. A 1g bov will probably make it run better though, as the stock 2g plastic bov usually starts leaking as low as 8lbs. The 1g would seal up the leak and correct the a/f ratio resulting in more power. The only way to tell if the bov is leaking is to do a boost leak test. If you want the turbo to spool faster, port the manifold and o2 housing, make sure you have no exhaust leaks and upgrade the exhaust. A mbc's only function is to control the opening of the wastegate which diverts exhaust gas from the turbos exhaust wheel, in turn controlling the amount of boost the turbo produces.