Installed Boost Gauge but stock at 15PSI??

[oimirageio]

Hey guys,This is one of my first real question's here so don't flame on me too bad if this seems like a stupid question.

First things first, this is a 1996 2G 4g63 with 98,000k.
Now down to business, so I installed my Boost gauge today and took it for a run around the block. I have not done any mod's to my car except a K&N Filter & Chrome Pipe. So @ WOT my car hits 15 PSI WTF , I did not think without adding in a MBC this could be running that high.
I also have a stock BOV until Wednesday, when I am installing a HKS SSQV but thats off topic.

So my main question & concern right now is why is it running stock at 15psi????

I do have a MBC I ordered and got yesterday so should I install that and pray its not at like 18-20 if its running at 15 now? Or will the MBC allow me to to control my boost more then the stock setup?

Thanks

 

[absolute_DSM]

Hey guys,This is one of my first real question's here so don't flame on me too bad if this seems like a stupid question.

First things first, this is a 1996 2G 4g63 with 98,000k.
Now down to business, so I installed my Boost gauge today and took it for a run around the block. I have not done any mod's to my car except a K&N Filter & Chrome Pipe. So @ WOT my car hits 15 PSI WTF , I did not think without adding in a MBC this could be running that high.
I also have a stock BOV until Wednesday, when I am installing a HKS SSQV but thats off topic.

So my main question & concern right now is why is it running stock at 15psi????

I do have a MBC I ordered and got yesterday so should I install that and pray its not at like 18-20 if its running at 15 now? Or will the MBC allow me to to control my boost more then the stock setup?

Thanks

MBC = manual boost controller. Its how you control how much pressure your wastegate sees, in turn "controlling" the boost to a certain level.

If the car was mostly stock when you got it, most likely the "free mods" were done to it. Search for free mods.

 

[Gregory]

yea, the boost solenoid restrictor was probably removed.. and yea, the boost controller will do exactly what it sounds like it does, so you will be able to turn it from about 11psi up to whatever you want. I wouldn't recommend going any higher than 15psi right now. I have stock fuel system and run 14psi just to be safe.

 

[oimirageio]

Yea I said the helll with it and installed the MBC to see if any change, It responds better so I am happy. Tomorrow I should get my BOV in the mail and see if that helps since the stock BOV is just dumping most of the boost over 11psi back into the intake.

Thanks for the reply's now just need to get a FMIC & walbro fuel pump

 

[Mr Peepers]

Don't forget an afpr with your fuel pump

 

[toojung2die]

So my main question & concern right now is why is it running stock at 15psi????

15psi is on the high side for the stock plastic 2G BOV. Two of my first mods were a MBC and boost gauge, still using the stock BOV. I couldn't get the boost over 11~12psi no matter how far I adjusted the MBC. Soon afterwards I installed a 1G BOV and on my first test drive I maxed out my boost gauge at 20psi. The plastic 2G BOV leaks like a rusty bucket above stock boost and in my experience could not hold 15psi. Your boost gauge may be reading higher than actual boost. Does it sit at 0 when the engine is off?

 

[B-Dog98]

I also have just a K&N filter and pipe, and I constantly will hit 14 psi whenever I got WOT in 3rd gear. In 2nd at WOT I can get it to about 12 psi and then max at 14 psi in 3rd......I do not have the BCS restrictor removed at this point either. My stock BOV is probably leaking a good amount though, but for some reason I will hold 14 psi until I let off.

 

[delta448]

15psi seems a little high, where did you tap into for the boost gauge?

In this picture you can see the "fuel pressure control solenoid" between the brake and clutch master cylinders, this solenoid is only used for starting the car when the engine is already hot (when it needs less fuel to start) and you can use the vac lines coming off either side of it to connect your "T" for the boost gauge without any ill effects. I and several others use this location and the cars still start and run fine with this solenoid eliminated. I recommend moving your boost gauge signal line there if it isn't already tapped there. It will give you a very accurate reading of the pressure in the intake mani, which is the true boost/vacuum value.

 

[oimirageio]

Your boost gauge may be reading higher than actual boost. Does it sit at 0 when the engine is off?

When the car is off it sits at 0, When I turn on the car at idle its at -15, when at WOT it maxes at 15psi. Just for the record im not bitchin that its at 15psi but more of just amazed and curious as to why. I now have the MBC installed and it is tightened all of the way down and I still hit 15psi now at WOT....

 

[quiksilver38]

stock boost is 14.7 and your reading 15 on your gauge whats the problem. it could be something as simple as the weather. you'll hit fuel cut (feels like you hit a 1 foot tall speed bump) if you go anymore than 16psi on stock fuel pump. be carefull when turning your boost gauge and do it on a deserted road so you don't get "mesmerized" by the boost gauge and crash.

 

[oimirageio]

15psi seems a little high, where did you tap into for the boost gauge?

In this picture you can see the "fuel pressure control solenoid" between the brake and clutch master cylinders, this solenoid is only used for starting the car when the engine is already hot (when it needs less fuel to start) and you can use the vac lines coming off either side of it to connect your "T" for the boost gauge without any ill effects. I and several others use this location and the cars still start and run fine with this solenoid eliminated. I recommend moving your boost gauge signal line there if it isn't already tapped there. It will give you a very accurate reading of the pressure in the intake mani, which is the true boost/vacuum value.

That is where I tapped my gauge in at with a T fitting, I just followed the line from the upper intake to the fuel pressure control solenoid and mounted a T fitting there so the hose would come up through the steering column boot and mount up without having to go crazy with the firewall. So if its not the location maybe My GST is just special or with my luck in about 2 weeks after overboosting & not knowing I will be .

Well it might be possible that the previous owners mounted a 1G BOV, because like mentioned before about the stock BOV's & how they leak like an oil pan without a plug ...

Thanks for the idea's and help guys if anyone can think of something else let me know, i am kind of going along the line right now of if it aint broke dont fix it because its driving fine and idle's great so I dont see a problem it is more of just a how is my bov holding that much boost and why was it boosting at 15PSI without the MBC. Now that it does have the MBC its at 15 but closed all of the way so I know alot of people had issues with that saying they cant go lower then 15PSI after installing a MBC on there cars.

 

[quiksilver38]

When the car is off it sits at 0, When I turn on the car at idle its at -15, when at WOT it maxes at 15psi. Just for the record im not bitchin that its at 15psi but more of just amazed and curious as to why. I now have the MBC installed and it is tightened all of the way down and I still hit 15psi now at WOT....

you probibly also hooked up the boost controller wrong or its on max boost and all the boost over stock is escaping through the stock BOV. be careful or you'll overspool your turbo

 

[oimirageio]

stock boost is 14.7 and your reading 15 on your gauge whats the problem.

No problem was just curious why, Im new to DSM's and I read that most people were getting around 11psi without a MBC. I agree with you and like i said earlier im not bitching I was just curious ....

so be carefull when turning your boost gauge and do it on a deserted road so you don't get "mesmerized" by the boost gauge and crash.

Haha Almost already happned, after installing the gauge went for a test drive with my friend and we both were staring at the PSI and not the road.......

Its amazing how easily entertained we can be, But we love our Toys!!!

 

[oimirageio]

you probibly also hooked up the boost controller wrong or its on max boost and all the boost over stock is escaping through the stock BOV. be careful or you'll overspool your turbo

Wouldent I hear it if it was letting out that much boost????? Also I dont want to sound ignorant but its kind of hard to install the MBC wrong with all of the instructions from this site + Vfaq........

I could be very wrong and putting my foot in my mouth but it seemed simple enough. Truthfully installing the boost gauge was harder then the MBC, I mean you remove the 3 hoses on the one T fitting, cap off the intake pipe nipple and put the MBC between the wastegate and the nipple below the intake on the turbo. Once that is done you make sure the MBC is tightened all the way down and wala its like makeing ramen noodles.... Then again I never was a good cook ...

 

[toojung2die]

Wouldent I hear it if it was letting out that much boost????? Also I dont want to sound ignorant but its kind of hard to install the MBC wrong with all of the instructions from this site + Vfaq.........

Sounds like you've done your homework. What quicksilver is saying is that you can have the MBC set to spool the turbo up over it's safe limits and not be able to see it because the excess boost is leaking out of the BOV before it gets to the intake manifold where you are reading boost. Back out the MBC screw until the peak boost starts to drop below the 15 psi max you are now seeing. Then turn it back in a tiny bit and lock it down. You want the MBC to be controlling the max boost, not the leaky BOV.

That's what I was inadvertently doing when I still had the stock plastic BOV. I didn't discover my error until I installed a BOV that didn't leak. On my first run with a good BOV my boost gauge buried itself to the max. My turbo was pushing over 20 psi and I didn't know it!

 

[oimirageio]

Back out the MBC screw until the peak boost starts to drop below the 15 psi max you are now seeing. Then turn it back in a tiny bit and lock it down. You want the MBC to be controlling the max boost, not the leaky BOV.

I have a Dejon MBC, I turned it to the point to where I couldent blow thru it then hooked it up. If i turn it the other way then I would be at 30PSI, not that I dont want to be but something tells me that would be one of those bad ideas hehe ..... I get my BOV in a few days when I install that we might get a few answers.

On my first run with a good BOV my boost gauge buried itself to the max.

Momma always said if your gonna go, go out with a big bang........

 

[TjPhillips36]

Yea I said the helll with it and installed the MBC to see if any change, It responds better so I am happy. Tomorrow I should get my BOV in the mail and see if that helps since the stock BOV is just dumping most of the boost over 11psi back into the intake.

Any BOV you put on your car MUST recirculate...

http://www.dsmtuners.com/forums/search.php?searchid=2998644

 

[oimirageio]

Any BOV you put on your car MUST recirculate...

http://www.dsmtuners.com/forums/search.php?searchid=2998644

That is correct that's why I said its dumping it back into the intake and not the atmosphere. If you dump into the Atmosphere your MAF thinks the air that was dumped from your BOV is still being sent into your engine. Hence, you will run rich and then all sorts of fun things can happen!!! (NOTE: I AM KIDDING DO NOT DUMP INTO THE ATMOSPHERE IT IS NOT FUN)

There are ways around it if you want to run the GM MAF but we wont get on that topic here.

 

[Splitpi]

15psi is on the high side for the stock plastic 2G BOV. Two of my first mods were a MBC and boost gauge, still using the stock BOV. I couldn't get the boost over 11~12psi no matter how far I adjusted the MBC. Soon afterwards I installed a 1G BOV and on my first test drive I maxed out my boost gauge at 20psi. The plastic 2G BOV leaks like a rusty bucket above stock boost and in my experience could not hold 15psi. Your boost gauge may be reading higher than actual boost. Does it sit at 0 when the engine is off?

I will second toojung2die's statements and say that that is most likely your problem. I had a similar issue as he stated and you are seeing. An upgraded BOV solves the issue.

Also, what kind of MBC are you using? Usually twisting it tight as you mentioned above means you set it too its maximum setting and pressure... there for the only thing saving your turbo is your leaky 2G BOV. Back off the MBC to a safe level that doesn't peg your boost gauge... perhaps even the safe side of 9.5 psi. Replace the BOV with an aftermarket (that recirculates) or a 1G (cheap and works great), then start increasing your boost again. Note the T25 really isn't much affective over 15 psi.. and anything above 17 psi is really just a hair blower .i.e. the gain in power is minimal.

It has also been before. A quick search would have found the same advise.
http://www.dsmtuners.com/forums/search.php?searchid=2998765

 

[delta448]

stock boost is 14.7 and your reading 15 on your gauge whats the problem. it could be something as simple as the weather. you'll hit fuel cut (feels like you hit a 1 foot tall speed bump) if you go anymore than 16psi on stock fuel pump. be carefull when turning your boost gauge and do it on a deserted road so you don't get "mesmerized" by the boost gauge and crash.

I respectfully disagree. I've never heard of anyone hitting 15psi on a stock 2G without a boost controller. I think that 10-11psi is the stock wastegate spring rating, not 1bar. Also, I have run 17psi on a 14b with the stock fuel pump, and the 14b flows a bit more air than the T25 at the same boost pressures. I'm not saying this much boost is a good idea for everyone, but your car isn't going to magically blow up or hit fuel cut with absolute certainty after you pass 15.9psi. I'm sure you knew what you were trying to say, you should just explain a little better when you make statements like those and not just throw it out there.

 

[toojung2die]

I have a Dejon MBC, I turned it to the point to where I couldent blow thru it then hooked it up. If i turn it the other way then I would be at 30PSI, not that I dont want to be but something tells me that would be one of those bad ideas hehe ..... I get my BOV in a few days when I install that we might get a few answers.

Is it the Dejon MBC-1? If so, it looks like it works like any other manual MBC. Turning the thumbscrew in increases pressure on the ball and increases boost. Backing it out decreases pressure on the ball and decreases boost. I'm suggesting you decrease boost until you see the MBC is having an effect. As you say, this will all be cleared up when you replace the stock BOV.

 

[gsxeclipse97]

Well 15 is normal as far as i am concerned. there are again to many factors to explain why you have 15 psi for example altitude will play a large factor. if you are closer to sea level than your car will not have to work as hard to build boost, air tempature cold air vs hot air, thats like night and day or a turbo. 15psi on a t25 will not hurt you. you can run 15 on a 14b and it flows well more air than a t25 (with stock fuel pump and injectors). the t25 doesn't even hold 15 past 5k rpms.

 

[oimirageio]

Awesome thanks for the idea's and help!!! I got my HKS BOV today but I dropped the car off to get a new paint job so we will find out in about 4 days when I get the car back and install the new BOV....

+ =

 

[MelloEclipse]

stock boost is 14.7 and your reading 15 on your gauge whats the problem. it could be something as simple as the weather. you'll hit fuel cut (feels like you hit a 1 foot tall speed bump) if you go anymore than 16psi on stock fuel pump. be carefull when turning your boost gauge and do it on a deserted road so you don't get "mesmerized" by the boost gauge and crash.

ooo look at the pretty gauge....15psi...wtf....crash. hmm...wonder if that's ever actually happened.


i wouldn't worry TOO much about it. but you should definitly fell better once the BOV is in.

 

[Splitpi]

Awesome thanks for the idea's and help!!! I got my HKS BOV today but I dropped the car off to get a new paint job so we will find out in about 4 days when I get the car back and install the new BOV....

+ =

I hope you bought an adapter or a differant UICP to mount the BOV too. As it won't fit without an adapter or a spefically flanged Upper IC Pipe.