unexpected boost levels

[nismoguy180]

I have just completed my swap...all factory spec parts minus exhaust and walbro fuel pump, and having installed a boost gauge I'm getting around 13 to 14 pounds of boost. Would anyone possibly know how that can happen and also if it is safe to be running that much boost on factory intercooler,injectors, etc? Any help would be appreciated.

[Blown240sx]

Id say either you got lucky and got a aftermarket Actuator or you have a vacum leak on the signal line for the wastegate.

Also I ran 13 psi on the factory injectors and Side mount only problems I realy had were bad heat soak from running only the SMIC.

[nismoguy180]

well that reassuring. I was worried I'd do some catastrophic damage to the engine running that much boost. I know the t25 is only good for 15psi,and i know you dont want to run your injectors at 100% duty cycle either. So really I just wanted to make sure that 13-14 psi wasnt going to overload the engine and do some serious damage.

[S13FASTBACKSR]

ya its said that the t25 is good for 14psi and the sidemount is good for 14psi..not too sure about the injectors but if blown240sx has done it im sure you can..but remember you are pretty much maxing everything out as far as its limits so dont beat the hell out of it too much or you will have catastrophic damage..eventually

[nismoguy180]

well I'm not really sure I'm comfortable running it the way it is. makes me nervous. Any suggestions on the cheapest way to remedy this problem outside of bigger injectors and safc? I'm on a really tight budget. Also would it be possible to get the factory spec actuator and return the turbo to factory boost levels til i can afford to get neccessary parts?

[S13FASTBACKSR]

yes that is possible but first make sure you dont already have a factory actuator...make sure it is aftermarket before you buy one..also check the vacuum line running from your actuator make sure it doesnt have any holes it it because that could also be the reason for this problem

[nismoguy180]

I checked the vaccuum hose and its good, no problem there. I am however from st. louis and I spoke with one of the reps from adrenaline motorsports and they told me I could purchase a boost controller and that should solve all my problems and allow me to run lower boost. I'm new to the turbo bits and I never knew you could use an mbc to turn down boost. Only thought you could turn it up. Is this true? If so I think it probably is the cheapest way for me to get this car running safely. Anyone agree or disagree? Input is appreciated.

[Luke]

Find a correct wastegate actuator. No your setup doesn't support 14psi at all. The max boost you should run on the SMIC is 10psi, as recommended so many times. Anything above that you'll run into heatsoak and detonation. Don't be stupid. Once you get a front-mount, you'll be find with 14 psi, but both the MAFS and injectors will be nearing their max.

[SpeedRacer1]

Stock SR's run about 11-13 psi stock. I wouldnt worry too much about the boost level.

Note: I know everyone is going to say "S13 SR's run 7 psi stock!" I know everyone says that. However when everything is hooked up properly during the swap INCLUDING the stock boost control solenoid you will run in the 12 psi range.

[Luke]

Stock SR's run about 11-13 psi stock. I wouldnt worry too much about the boost level.

Note: I know everyone is going to say "S13 SR's run 7 psi stock!" I know everyone says that. However when everything is hooked up properly during the swap INCLUDING the stock boost control solenoid you will run in the 12 psi range.

Maybe that's what your SR does, but no, it's 7psi.

Also, the function of a MBC is to "restrict" boost pressure going to the wastegate, therefore causing the flap to open later, creating more boost.

[SpeedRacer1]

Maybe that's what your SR does, but no, it's 7psi.

Like I just said above you need the stock boost control solenoid hooked up. I ran my SR for 4 years at 7 psi, then I put the stock boost control solenoid back on and boost jumped instantly to 12.

Luke are you running the stock boost control solenoid?

[S13FASTBACKSR]

the only aftermarket actuator i know of for the t25 is the hks one and its boost is set at 11psi I believe but i think its adjustable..try adjusting it down..plus if you have an aftermarket actuator such as the hks one i dont think you can use a boost controller..because the actuator sort of serves as a mbc (hence it being manually adjustable)..same as if you had this actuator with an electronic boost controller..you can only use one or the other.

[DRIFTINIZ]

in order to run an mbc.....do you need to do nething w/the factory boost solenoid or whatever......and i kno i'm sure this has been asked b4 but there is a diagram on the forum somewhere that has the diagram for an mbc hookup.........neone got that???