I tightened up the BOV on my Vortech to the point right before it whistles all the time and took her for a spin. I hit 9.4 psi at 7000 rpm! Can this be right? I guess I'm building boost sooner and my belt isn't slipping. It was a nice 55 degrees out last night. Can weather have an affect on how much boost you can make? I always thought the Zeitronix boost gauge was pretty accurate. I still have a stock tune. Can the stock tune handle this much psi out of the box? My A/F for those runs was still 10:1.

 

I know I've seen Q45tech post about air temp and psi ... don't quote me I want to say for every 11 degrees F, the air density changes by 1%. So yes you could achieve higher boost pressure with lower ambient air temp. The ambient air temp when your car was tuned could also be a factor if it was tuned with ambient air temps that are high.

I'm not sure why tightening the bypass valve would have changed your boost pressure unless it was never closing completely during boost (WOT).

I'm not running any gauges so it's hard for me to say, but if your A/F is steady at 10:1 then you are good to go!

 

From what I've read, tightening the BOV allows it to close earlier in the rev band. This could account for some extra psi, but not 1.4 psi. My car has not been tuned. I still have the stock Vortech tune and a 7000 rpm redline.

 

Your car has not been tuned.. How long have you been driving without a tune? Thats scary.. The tune is the most important process of all...

 

Thats scary.. The tune is the most important process of all...[/QUOTE]
i'll second that notion

 

Ummm, guys...the "tune" is to make the car run more efficiently and make more power. Actually, if everything is running correctly (i.e. timing and fuel maps and install), running the pig rich stock Vortech tune is the safest alternative. However, my wallet thinks otherwise, so I'm awaiting a tune. I have AFR, Boost, EGT, and fuel pressure gauges, oil pan spacer and a J&S Safeguard. I'm pretty safe now, but actually worried about a bad tune. You're telling me the stock Vortech tune isn't safe?

 

The baseline "pig rich" Vortech tune is relatively safe. But there is more than just A/F that goes into a tune, you have to also consider timing retard at RPM and different boost at RPM.

The baseline tune does not take into consideration any of the variables that your car may have like intake, cams, exhaust... From what I understand the baseline tune is meant for a completely stock setup.

 

remember, pig rich isn't always good...that's how you replace injectors! Withthat said, Vortech's pretty good about their stock tune out of the box...if you're acheiving 9.4lbs at 10:1 AF, you're doing well. Where are you reading the AF from?

 

low temp will run higher boost. Yeah it's dangerous - get it retuned sometime for the colder weather or don't drive the car hard until it warms back up to the temp when you initially tuned the car

 

BeerViper, my only other mods are Crawford cast plenum and Gruppe-S Y-pipe. The stock tune is also very conservative on timing retard also. I actually let the J$S pull timing for me and let the SS box do fuel until I figured out some problems. I've heard the stock Vortech tune pulls 10 degrees of timing at 7000 rpm, which is very conservative. I'm not sure if the split second is pulling timing based on RPM or boost, but it's very conservative. I think the stock tune will accomodate more than 8 psi. Again, a dyno tune will yield more power.

Randy, I'm pulling A/F from the Zeitronix and Bosch sensor in my passenger side header before the cat. The EGT is in the driver side header closer to the block. I do agree with you on the injector replacement. Although it's in my future plans, I really don't want to deal with it now. Thanks guys.

 

Without a tune, you are asking for that motor to blow up... How could you know anything for sure whats going on with that car if you have had no tune. You said the gauges were reading a excellent AF mixture, but still that like driving in the unknown. Be safe and smart get tuned. It dosent matter how safe people say the out of the box tune is, it only takes one lean spot and boom... " I THINK the stock tune wull accomodate more psi". How could you say that and be safe. You want to know exactly where your car is at when it comes to tuning. Ask any FI guy, a tune is a must, most important. Hey I just want your car to be running safe and not have problems. By the way the stock piggy back from Vortech is the cheapest setup you can have when it comes to tuning. It is the bare mininum to keep the car safe.

 

The stock voretch tune is sh**. Just like every other company they want to have a good price for there setup out of the box and not charge a huge price. So vortech supply's the lowest cost ECU that will work just enough to say the kit works. "I'm pretty safe now, but actually worried about a bad tune", that statement is completely backwards. Your not safe unless the car is tuned period.......

 

Errr, I think you need to check out My350z.com to see how many engines have blown due to bad tunes. I'd rather run rich, than let someone who doesn't know what he's doing touch my car. How many FI guys have blown their engines with a stock tune? In fact, I don't know of any engines lost to a stock Vortech tune. Most guys are pushing HP way past what the manufacturer's claims were. I have a tune coming soon, my tuner's dyno is currently down. In the meantime, I've done many hours of data logging with the Zeitronix. I know exactly where my A/F, EGT, and boost is every rpm to redline. Can you answer my original question about the stock Vortech tune being able to handle 9.4 psi? I already know the box is calibrated up to 7k rpm, I just don't know how much psi its calibrated for.

 

Yes...you will make more boost in cooler temps .


The SS box is more than capable of a good tune on the Vortech , Stillen , JWT TT , and one other TT kit . It is a lower priced EMU . But if it wasnt good enough , I dont think all of these companies would be using it

 

Thanks, Bill.

Do you know how much psi the stock tune is calibrated for? Need I worry about hitting 9.4 psi on the stock tune?