Now that I have a boost gauge installed, I seem unable to get any boost above 3 or 4 psi at WOT. Is it possible for the BOV to be leaking off boost even with a tighter-than-factory setting of 5 threads showing? All the piping seems tight and there are no other obvious sources of leaks.

Under hard throttle, I can hear the BOV close (the "whoosh" sound stops). Still pretty wimpy boost and no where near the 8 psi I was expecting with the Vortech.

 

Out of the box three (3) to four (4) at WOT without doing some additional mods is probably what you are going to see. Just finish doing some dyno pulls with mine on Thursday and I saw similar numbers. I am at 5000 feet elevation and don't know if elevation impacts "boost". I do know it impact POWER.

 

No way you should only be getting 3 or 4 lb's of boost . You either have the belt slipping or BOV leaking . I dont think its the BOV . But the only real way to tell it...when on the Dyno...Put your hand over it at WOT . May be another way...but I dont know it . I dont know what type of exhaust you have , but if its an open pipe exhaust , you may lose 1 or 2 lb's of boost . It possible you have a vacuum leak . Check your belt first , then check for vacuum leaks....Bill

 

altitude will not affect boost to that extent! like booger said, the most likely problem is a vacuum leak or boost leak. When my greddy kit was originally installed, they could only get 3 lbs of boost out of it, the shop tried to tell me it was because of altitude (in my ignorance i believed them) I began to learn more and found out how it really works; the boost may suffer an extremely small amount because of altitude but not from 8lbs to 3-4!...check all of your plumbing to make sure there isn't a boost leak and inspect all of the vacuum lines, altitude lowering the boost is bullsh!t- high altitudes will result in a decrease in oxygen saturating in a normally aspirated engine, when it comes to the world of boost- the affects are nominal.
Hope this helps

READ: Maximum Boost by Corky Bell
TODD

 

There probably isn't a vaccum leak because I'm getting great negative numbers (-20 or more at times). All the piping is solid. I'm still thinking it's the BOV. I adjusted it twice getting a bit more boost each time and no flutter, so I'm thinking its got more tho go. If 5 threads are showing, how sensitive to change are one or two more threads In? Does anyone have experience with this?

Thanks for all your help.

 

The more you tighten that bolt on the BOV , the earlier it will close . So if you have 5 threads showing , the BOV should be closing pretty early [ -4 to -6 in ] Of vacuum . I think if you have a boost leak , it will not effect vacuum . Depending where the leak is .
If your A/F is jumping around while cruising [ around 14.7 to 1 normal ] I dont think the SS box has any thing to do with it .
If I was you I would get on a Dyno to see if your A/F is good [ and if your Gauge is right ] and to see if you can find a boost leak....Let us know when you figure it out

 

IBOV does seem to be closing around -5-10 psi because when I accelerate, boost goes from -20 towards 0 but has a hard time getting over zero to about 3-4 psi, even with hard throttle. Is it possible for the BOV to close initially but not hold pressure over 3-4 psi? Often, It starts to boost but just poops out around zero.

The car has good power, but I'm not able to chirp my snows in any gear. Wonder where the leak would be if there is one. Everything seems solid and tight.

I will keep you posted. I'm planning on dynotuning ASAP. Just installed the system. Seems to be running well without any detonation.

 

check your belt tension. that was the biggest problem i had with mine. belt was always slipping and i alway had to tighten it.

 

Where is the gauge getting the Boost/Vacuum signal from?

 

I believe it's coming off the same vaccum line that's teed into the SS timing box. I believe the gauge reading is accurate because there's prompt response to acceleration up to about zero psi--then plateaus out and drops right back down.

Curious-- is the normal vacuum not under boost around minus 20 psi or so?

 

Update: It is normal to run vacuum around -20 at cruise. I believe I've traced the boost leak to a bad BOV. Vortech tech support was very helpful and is sending me a replacement. I'll post the result of changing it out in several days.

 

Just replaced the BOV with a new one from Vortech. Now, the boost is fine and the car SCREAMS. Vortech informed me that just this week they received back another bad BOV--it had a folded diaphragm--exactly what I think was wrong with mine. So now, it's completely fixed.

 

Congrats! Glad you were able to find & resolve the issue. Enjoy!

 

Are altitude does impact the Zeitronix Boost Sensor. The sensor is a 3.5 Bar Kavilco. According to Zeitronix, and based on the wideband charts that I posted which showed boost at 2.9 @ 6000 rpms the: Quote: "Atmospheric pressure at our altitude is -5.05 inHg. Your engine makes 2.9 PSI Albsolute pressure. Those are pleasures of tuning at higher altitude. Everything changes, AFR, concentration of oxygen in the air, alsolute pressure. It's a different ball game than Florida. Kind of like tuning car in winter and summer. Ambient temps and changes in oxygen concentration from the temperature make a difference. Welcome to the art of tuning . This is how boost gauges work in general. You just do not notice it as easily on the mechanical gauge. Besides mechanical gauges are usually off from the get go. Once you roll down to the sea level your Zeitronix will show 0 PSI (+/- variations in the atmospheric pressure in a given day)." End-of-quote.