boost spike 20 PSI

[RayBan GST]

hi all,

i have been reading now for about an hour or so for the above subject ( Boost spike ) and i really need the following answers from you if possible:

first my mods are :
EVO 3 BOV ( PLASTIC)
MBC ( Bleed type cheap Ebay stuff) connected directly in the place of ISC ( just unplugged the ISC and plugged the MBC)
Turbo Gauge ( reading at idel 19-20 PSi in minus) ok ? ( please answer me on this)
after market Air Filter

the rest are all stock ( i just changed my timing belt and the water pump and the car is in good running order )

once i am at 2nd gear and floor it the boost will spike to 20 Psi and then goes down to 14 Psi ( i am sure its because of the cheap MBc because if i go back to the original set up it wil hold steady 9-10 PSI. so no leaks

the question is would this spikking hurt the engine ( i am not hitting fuel cut or anything but i am really worried about this spikking 20 PSI is quite high on stock fuel system. i just want to know if this spike for a second or so would really hurt my engine ? ?

second question is ( when you set your boost to 15 Psi you have to set it for 20 Psi so it can settle at 15 PSi or you just have to settle it at 15 PSI to end up with 10 PSi ?????

Thank you very much

 

[casperfast]

the only way spiking could hurt your engine is if it detonates(pings) while spiking, leans out bad...could blow holes in pistons.but usually they hit fuel cut first. the spikes can also cause piping to pop off. and your boost gauge @ idle readings are normal, as long as theneedle isnt fluctuating while idleing.

 

[Rob10_99]

MBC's differ in that yes, you can get spikes. What type is it? bleed off or something with a spring/ball setup?
Follow one of the install guides, there's a lot on here about MBC's. I would hook up the MBC from TB side to the wastegate actuator. Now that your saying you have spike issues, I would hook up right to the turbo to prevent any spiking.
Your car's completely stock other than those mods listed?

 

[RayBan GST]

my MBC is a Bleed type and the connection is JUST fine ( the installation is right )

my car is 100% stock ( just the mods that i listed)


my turbo gauge does not fluctuate while ideling

 

[zhjiln]

if everything is hooked up properly and working right, that it sounds like you are setting it to 20 psi and the turbo is falling off pace at higher rpms ...which is normal to lose a few psi on the stock turbo....

 

[RayBan GST]

thx
i really need more feedback on the SPIKE issue if it hurts the engine or not ?


i just want to know more i am really worried about this spikes .

please more and more feedback on this issue ????????

 

[niles]

Turbo Gauge ( reading at idel 19-20 PSi in minus) ok ? ( please answer me on this)

18-20 inHG is okay.

once i am at 2nd gear and floor it the boost will spike to 20 Psi and then goes down to 14 Psi ( i am sure its because of the cheap MBc because if i go back to the original set up it wil hold steady 9-10 PSI. so no leaks

Try to lower boost with the MBC, perhaps it is adjusted too high and only the leaking BOV limits the boost to 14psi. I had a similar problem after installing a 3" turbo-back exhaust. My problem disappeared after adjusting the boost.

 

[Dsmj89]

It sounds like you have your mbc set too high. Turn it down to 14 psi if that is what you are holding.
A little enlightment, just cause you spike 20 and hold 14, doesn't necessarily mean turning it down to 15 will hold 10. If your wastegate can support 14 psi strong, it doesn't matter what boost setting you set your car to as long as it's not under 14, it will hold 14 psi in the end regardless.

 

[spyderturbo007]

Try shortening the length of the MBC vacuum lines.

 

[98GSXtreme07]

hi all,

...
first my mods are :
EVO 3 BOV ( PLASTIC)
MBC ( Bleed type cheap Ebay stuff) connected directly in the place of ISC ( just unplugged the ISC and plugged the MBC)
Turbo Gauge ( reading at idel 19-20 PSi in minus) ok ? ( please answer me on this)
after market Air Filter

...

<b>Am I the only one that caught that?</b> I guess everyone knew what he meant on the ISC being the BCS?

BTW, I would guess your "minus", which is Vaccuum, is good but it really differs from country to country, region to region and place to place. It reads different in the area your in. Dependant on how high or low you are above or below sea-level. I've heard, not positive on this, that it can tell you how "healthy", compression-wise, your engine is.

 

[toofast82]

if it is one of these: eBay Motors: R MANUAL BOOST CONTROLLER RX7 RX8 MX5 MIATA MAZDA 6 3 (item 320333239395 end time Jan-22-09 09:11:26 PST)
I would follow these hookup instructions and make sure you use the tee
http://www.dsmtuners.com/forums/new...l-turbosmart-tee-style-bleeder-style-mbc.html

It also could be the plastic bov is incapable of holding more than the 14psi

 

[RayBan GST]

yes its the same MBC on ebay and i did not use the T as there is one with a restrictor already in our STOCK SET up so i just connected it straight instead of the BCS


i tried to adjust the boost its spiking now 15 psi and then go down to 9 PSi


can you please answer me on the HARM of the engine question that i raised , does spiking for a second or so to 20 PSI damage the engine?


thanks

 

[casperfast]

like i said, it can toast your pistons, and possible a head or some valves. just turn your boost controller down and watch the result. theplastic bov'sleak past 14ish psi so i can spike and then bleed out though the bov, just lower the boost, you should be able to get it to hit and hold 15 psi

 

[RayBan GST]

thanks man but my BOV does not leak at 14 psi ( its a PLASTIC EVO 3 BOV its exactly the same as the plastic EVO 8 BOV)


i just can not get it right , i set the boost to 15 its goes to 9psi and then i set it at 16 Psi it spikes to 22 Psi and then down ?????????? what is happening

 

[TalonRacerTSI]

Why not just buy/find a 1g bov?

 

[RayBan GST]

why should i if i have a good BOV ??? my BOV can hold easily 18 Psi and i am not even close to that number

 

[96eclipseawd]

I had that same mbc, and I couldn't get it to hold. Either it was 10psi or 20. It blew the seals out my stock t25. So I put a B16g in, and I just hooked it back up to the stock bcs until i get a new mbc.

 

[Orion97gs-t]

Ya i had the same problem with my eclipse, I had a plastic BOV. I just upgraded and now it works fine.
Question though, what does it mean when your PSI gauge is flickering?