t25 spike no mbc

[GotARed]

Today I was installing my boost gauge, and before I installed the mbc I noticed with the stock controller was letting it go 17-18 psi as soon as I banged a gear, every gear.

Does this typically happen, I always believed 11-12 stock was the psi range to be at. So should I put my mbc on or let it be?

Is 18 psi too much for my stock head gasket? I know it is pushing it. Fuel is not a problem. : P

 

[DSM_PWR]

make sure your boost gauge is installed correctly. where did you T your boost source from?

also do you have your stock bov? make sure your bov isnt leaking anywhere as that will lead to some spike.

 

[GotARed]

I have an evo 8 BOV and I T'd from the FPR line. We tried two different guages and they both read the same.

 

[DSM_PWR]

install the mbc, set it low and see if that takes care of it

otherwise boost leak test it.

i had the same thing but it was just a leak by my bov

 

[2GAWD4U2NV]

Hey bro, I'm not for sure if we are on the same page, but maybe you meant the fuel pressure solenoid line? It is the last nipple on the intake mani on the driver's side. Also, make sure your lines are right. I'm currently on my T-25 and I've messed with it enough that I don't have anymore boost problems... x-( Anyways, factory T-25 T's off of the wastegate... eliminate that. Now you should have a vacuum line off of the turbo and off of the wastegate. The line off of the turbo plumbs straight into the small nipple on the intake by the radiator fan. Hook that line up. Now, grab your MBC. It has a wastegate side and boost source side. Grab some vacuum hose and run the vacuum hose to the wastegate nipple and to the correct side of the MBC < VERY IMPORTANT! Now for your boost source: If we are on the same page, you can run a vacuum hose to the fuel pressure solenoid. This is a great boost source. Works great. It is currently where I have my boost source for my MBC and boost gauge. If you don't want two sources on the same line, you can run either one, your preference, to the "p" port right by the throttle body. Either way, run the vacuum hose back to the boost source nipple on your MBC < VERY IMPORTANT! If it wasn't 11:20pm, I would snag some pics of my set-up for you. I will get back in touch with you tomorrow. If you don't have it solved by then, I will throw some pics up for you. Good luck!

JWoodley

 

[95burgundyesi]

Me and GotaRed were preforming this on my car. We hooked it up right, but it was spiking 17psi and holding 15-14 until 5300k without touching a thing!!! And Now it spikes to like 20and falls to 9 : / . For now we just put a line from the aculator tothe boost source on te turbo so its only at like 10psi.

Hmm maybe I should get a CHEAP 14b so I can accually play. But then I got to waste more money on getting it together and on when I will outgrow it in like 2 months.

 

[DSM_PWR]

Ok so please make sure your install looks like this:

For the Boost Gauge Make sure its tapped Here

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And make sure your mbc is like this

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Set the MBC to the desired boost level

If your still spiking then you might just have a bad mbc

 

[blkwidow]

Today I was installing my boost gauge, and before I installed the mbc I noticed with the stock controller was letting it go 17-18 psi as soon as I banged a gear, every gear.

Does this typically happen, I always believed 11-12 stock was the psi range to be at. So should I put my mbc on or let it be?

Is 18 psi too much for my stock head gasket? I know it is pushing it. Fuel is not a problem. : P

Well if you're on a T-25 then 18psi wouldn't net you anymore more power then you would at 14-15psi. I would set it at about 14-15lbs. After the install it wouldn't hurt to check for boost leaks. To answer your question, 18psi would be fine on an OEM head gasket.

 

[Zmann42087]

I was spiking to 19 psi with the stock BCS (no MBC) back when I had my T-25 turbo. Honestly, I never got it figured out and I was always afraid I was knocking (didn't have my logger back then).

This past summer I changed my turbo setup to a ported FP BIG-28, a Hallman Evolution MBC, PocketLogger, etc. and now I have no issues. Unfortunately, I installed all that stuff at the same time so I can't tell you exactly what it was that fixed the problem. For instance I don't know if it was the turbo itself, a faulty stock BCS, a bad/expanding vaccuum hose, a stuck wastegate actuator, etc. <-- Those are some things I'd definitely check though!


edit: just noticed your vehicle profile says you have a '91 GSX.. are you sure we aren't talking about a 14b turbo here? The T-25 came on 2g DSMs only.

 

[95burgundyesi]

No, we just posted under his name because I was down in springfield. I am just going to run a staright vac hose from the source to the aculator. Making me not spike and si at 10 psi.

 

[JusMX141]

Just out of curiosity, what size exhaust are you running? Full turbo-back 3"?

 

[95burgundyesi]

Stock but im working on it. There is talk from my friend if I can find a big or evo 16g for 300 he will give me his small 16g for 100, and I when I do that I am going megan 3 inch dp, and either a cutout with stock catback or muffler shop 100 bucks cat back.

 

[Zmann42087]

Stock but im working on it.

well, that rules out boost creep as the problem..

 

[95burgundyesi]

Stock not touching anything was at 17psi and 15psi by 5300k then by 6k about 12. I was so sad after getting the mbc on there. So now im going to just leave it be and work on other bolt ons.

 

[BoostedinSoFla]

Are you gonna hook it back up to your BCS?

 

[95burgundyesi]

No, im being lazy and using just the vac line from the boost source straight to the aculator. Gives me 12 psi on the hit and 10psi everywhere else.