16 PSI w/o boost controller...why?

[BGSpyder]

I'm fairly new to the modding thing but I'm learning fast. One thing that I need some knowledge on is why, with my mods, did my boost go up to 16PSI w/o any type of Boost Controller installed....yet?

 

[BGSpyder]

Opps...here's the mod list so far:

K&N FIPK, 2.5" Custom Downpipe ,3" Custom Cat-Back exhaust, MagnaFlow Muffler, 1G BOV, RRE Lower UIC pipe, Dejon Tool Intake MAS intake, Autometer Boost gauge, Apexi Auto TT

Coming soon: Fuel pump rewire, Dejon Tool MBC

 

[CraigB]

Is it a spike up to 16 or does it hold at 16? It is because of the exhaust on your car.

 

[krott5333]

Umm... im not sure, dont quote me on this, im a newbie.

But I think thats because you have a 2.5" downpipe, with a 3" catback. I bet if you got a 3" downpipe, itd take care of that, and bring it back down to around 11-12. www.rnrracing.com has an 3" o2 Eliminator downpipe for pretty cheap.

 

[BGSpyder]

It peaks at 16 PSI until about 5K RPM and then down to around 10. I've read somewhere else on here that the T-25 can't hold higher boost levels above 5K RPM, so I assumed this is normal.

 

[nine5raptor]

Did you do the bcs mod?
do the fuel pump rewire and don't worry about it too much...I ran 19psi on my T25 and rewire with no probs. to get boost above 5k get a bigger turbo.

 

[BGSpyder]

No I didn't remove the nipple. I've hear some guys saying that they just had to put it back in later, so I figure I'd leave it in for now. I really have not plans to remove it.

I'm not too worried about it I was looking for a quick explanation of why it when up. And when I install the MBC could I lower it back down to say 14 PSI? Thanks for the input concerning the fuel wire mod.

 

[stuntgixxer]

mine does the same thing, 16psi till 5k.
It's not your 2.5 downpipe cuz mine is all 3".

 

[nine5raptor]

not sure why your boost is so high. the factory bcs should limit it to around 11 psi assuming all lines are still hooked up like stock, which if they weren't, you would probably be running higher than 16.
you can run as low as like 10 with a ball and spring style mbc (I forget what the wastegate actuator is set at). The ball and spring blocks the air from reaching the wastegate actuator until the boost level is high enough to overcome the spring in the mbc. If you are below the actuator set level, the boost won't be enough to open the wastegate. you will also be bypassing the stock boost control completely.
with a bleeder, you can only raise the boost by bleeding off the pressure that the stock system "sees" and allowing to boost higher. This one still relies on the stock system to get it's baseboost.

hope this helps

 

[nine5raptor]

hmmm....must be a spyder thing

 

[CBgst]

Yes with a mbc you can turn down. Mine did the same thing.

 

[nine5raptor]

stunt--was yours like that with the stock boost control like bg's?

 

[elfili]

In my search to find a thread with the right question, I ran into this one.
I, too am still running the stock t-too slow turbo. Now I'm just questioning how much boost I can run safely with a fuel pump rewire?
I actually have a walbro 255, so is a rewire necessary?
Am planning on getting an MBC.

I have similar mods as BGSpyder.

 

[FourG63 97GST]

Originally posted by elfili
In my search to find a thread with the right question, I ran into this one.
I, too am still running the stock t-too slow turbo. Now I'm just questioning how much boost I can run safely with a fuel pump rewire?
I actually have a walbro 255, so is a rewire necessary?
Am planning on getting an MBC.

I have similar mods as BGSpyder.

It not really about how much boost you can run safely, but the T25 isn't very effecient above 15-16psi thats why people say thats the most you should run. It will create a little more power but will also decrease the life of the turbo since its being overworked. A rewire with stock pump w/ a T25 is good, but a walbro 255 is a bit too much fuel for it, so I wont rewire the 255 if yor have a T25

 

[Ryan95tsiAWD]

like someone else said...check all your hose connections, if the exhaust upgrade didnt do it then it sounds like you have a leak before the wastegate.

 

[EHeye]

I have a 1G, this may be irrelevant to your problem/glory but maybe it may help out. I have removed the insert in the BCS and it gave me 11psi, did a new vaccum line kit and it went down to 9lbs, so something in between the intake and the wastegate is doing something, so i took the lines off and the one between the "T" and the intake tube was smaller than the stock one, much smaller, so i checked out the old one and stuck it on, boom 15-16lbs of boost, i was like wtf, so i examined the tube a bit more and noticed a valve thing down in the vaccum line, so i grabbed some needle nose and pulled it out, 9lbs. So the little metal piece inside that shrunk the size of the hole down gave me more boost, it is a hollow insert. So im happy, no BC and I can run 9lbs, 11lbs and 15-16lbs =)

 

[icuinmyrearview]

also had the same prob but mine managed to happend in the wintertime where the temps were already giving my higher boost levels, i manage to spike up to about 20psi on certain cold nights, my lines are all in spec, and the actuator is fine, change happened when the 3" downpipe was introduced, so im assuming it could be the same for you, id def ad more fuel just to compensate for the extra boost (255's are only like $110w/install kit) then start focusing on wastgate function...im installing my prefec b and ported o2 sesnor housing as soon as this blizzard ends, ill let u know if it helps, your boost drop off above 5k is due to the Tiny25
p.s.:if it makes u feel any better at 19psi when running the stock fuel pump, my EGT's would peak at about 890C, not good, but not deadly either

 

[Terror_Eclipse]

hey whats up i had that same thing happen to me like 2 years ago when i first started to mod my 95gsx...

my mods were:
autometer boost+A/F guages
hyamaie UICP
greddy LICP
1G bov
1G throttle body
apexi 3" rsr cat back
injen intake
ported 95 manifold
cosmo fuel pump
and this thing...APEXI SAFC

after i put the apexi SAFC in my boost went naturally to 16psi and i didnt have a boost controller yet, anybody else have that happen to them when they installed a safc

 

[draculia]

its pretty normal. when i did my 3" exhaust, boost went from 11 to 13. when i did my upper ic pipe and 1g bypass valve boost went to 16.

the stock boost controll solenoid is set to keep the boost with a stock setup. once you start freeing up those restrictions, you make things more efficien the bcs is still seeing the same pressure from the turbo, but all the removed restrictions give less pressure drop. well, that's my take on it anyways.

 

[90 AWD]

I think its from the BOV mainly. The stock BOV on 2g's leak around 12 psi even though the stock boost is around 14psi. You add the 1g BOV and then you will see all 14 psi. The exhaust added the other 2 psi from it being less restrictive.

 

[elfili]

How can I find out how much fuel Im actually feeding?
Can I find this out using a pocketlogger or an S-AFC? FPR w/ gauge?
Basically, I'm figuring out my next mod, but at this point I'd like to monitor the amount of fuel I'm providing. All this before I intend to string out the T-too small.The walbro doesnt need a re-wire, I understand, but what tool can I use to tune the amount of fuel I'm actually getting.

 

[Desi4Life]

I had a similar problem on my 1G and it turned-out to be faulty vacuum lines. It was also due in part to OLD vacuum lines. They were not as efficient. I isntalled new wires from Summit Racing and my boost went from "creeping" up to 16 to a solid and controlable 12. I also learned that while this problem was occuring, my MBS was not very effective.

Desi

 

[generalu]

I was at 11-12psi, then after removing the BCS, it jumped to a solid 12-13. Then after I installed my downpipe I was hitting 15psi at WOT. So I'm guessing it's your downpipe. I'vd just repeated what most people have already mentioned. Anyone familiar with the Blitz Dual SBC? I have it, but without any instructions, and can't adjust things the way I'd like. Input appreciated.