Am I OK at 15psi??

[SteveR6]

Ok I searched alot and am still a little leary. I just installed a 14B on my 2G, I have an Apex power intake, apex downpipe and N1 exhaust (no cat) and a Hallman MBC I'm running a shade under 15psi (needle between 14 and 15) which for some reason spikes to around 17 when shifting second. Is this safe? Or should I turn it down? Unfortunately funds don't allow a datalogger right now so I have no idea if I'm gtting knock or not. I know the saf thing to do is turn it down until I get one but it's just so hard to go backwards performance wise .

 

[JayRolla]

If you dont have a logger I would not boost more than 12psi. You could be knocking really bad with that 17psi spike. Just to be safe you should turn it down. You dont want to damage your motor and hope your ok. Turn the boost down.

 

[SteveR6]

Why do you think it's spiking? I drove a girl/friends Talon and it does th same thing on the 1-2 shift, both are automatics btw.

 

[1g_tsi_awd]

Yea, 12psi max w/o a logger, you should look at gettign one.

www.dsmlink.com

 

[zippyshoe]

Why do you think it's spiking? I drove a girl/friends Talon and it does th same thing on the 1-2 shift, both are automatics btw.

To minimize boost spike, focus on how the MBC is connected. Keep the vacuum lines as short as possible going to/from your MBC. Also, make sure your MBC is NOT using the line running to your BOV as its boost source.

 

[JayRolla]

Do all MBC's just cause spike. I had no problem before the MBC now I spike at least 2psi when ever I do a hard downshift. If I boost slowly it holds fine. I have the shortest vaccuum line possible. How else can it be fixed.

Ebay has way cheaper loggers than dsmlink even though it would be nice to get dsmlink, it is real pricey

 

[skuls]

This is SteveR6 on my buddies s/n. I have the SAME problem if i ease into it I don't spike but if I'm WOT I spike. The lines are as short as I can make them and I'm directly into the nipple on the j pipe and the nipple on the wastegate actuator. As for the friends car, her MB is set up crazy like they just hooked it up in place of the boost control solenoid, so a proper hook up might solve her problem.

 

[MrGudbar99]

i've been running at 15psi for a couple months now. i haven't had any problems with it yet. but if you want to be safe, i'd go with what these guys are saying...turn it down until you get a logger or dsmlink.

 

[SteveR6]

Turned it down to 13, it's amazing what a couple psi will do

 

[Ultimatedsm]

Well 14B flows around 405 CFM compared to the T-25's 290-325 CFM. So there is more airflow which means you will run leaner. However, if you rewire your fuel pump or get a Walbro 190LPH, you should be able to run 15 psi no problem. The stock fuel injectors are around 90% duty cycle at that point so its not too bad.

I am just curious how large is your exhaust system?

 

[SteveR6]

2.5 into 2.75 after that flex pipe piece