Boosting at 10lbs + ??

Nomad_69er · Post by **Nomad_69er** » July 21st, 2007, 3:21 pm

Hey guys, I'm finally driving my baby. I'll post pics soon but something weird is happening. My turbo is running at stock boost and is climbing all the way to 12lbs. Isn't the stock boost for the VJ11 6 or so lbs? I talked to a friend of mine who is using the same turbo on his CRX and he's noticing the same thing....anybody else noticing the same thing out there? And by the way it's so much fun!! I love turbos!!

And it kept up to a 13 sec Mustang on the highway...muah haha!

cyclonekid78 · Post by **cyclonekid78** » July 21st, 2007, 3:42 pm

Sounds like boost creep. Might have to port your internal waste gate.

What kinda boost controller are you using.

I had boost creep issues till I ported mine and got a quality boost controller.

Nomad_69er · Post by **Nomad_69er** » July 21st, 2007, 4:20 pm

No boost controller....stock boost, like I said....strange eh?

cyclonekid78 · Post by **cyclonekid78** » July 21st, 2007, 4:54 pm

I'm pretty sure its boost creep. Might want to check your bypass valve. You need some kinda controller so as not to boost spike.

Nomad_69er · Post by **Nomad_69er** » July 21st, 2007, 5:48 pm

I was under the assumption that a boost controller only increases boost. So I assumed not putting in a boost controller would leave it at stock boost. If the stock boost which I am running right now is hitting 10lbs then wouldn't a boost controller just make it worse? And the blowoff valve that I'm using is an HKS SSQV. They should be fine to handle that kind of boost right??
Thanks.

osargeant · Post by **osargeant** » July 21st, 2007, 6:33 pm

A boost controller would only allow you to increase boost not decrease, I think you may have a modified wastegate which is why you are boosting that high. I have used IHI-VJ11 turbos before and the stock boost is around 7/8 psi.

You need to be very careful if you are boosting that high since you may not have the appropriate fuel or ignition retard to support it.

cyclonekid78 · Post by **cyclonekid78** » July 21st, 2007, 6:34 pm

If you have the Factory bypass valve you are ok. ( assuming you have a factory turbo swap) But the turbo needs a vacuum to open the wastegate. That is what a Bypass valve or boost controller is for. If you don't have these you can never stabilize your turbos boost levels. There for thats why your boost goes so high. You might want to do some more research so as not to blow up your engine. Im not trying to be a a-- here just looking out.

nos92mx3 · Post by **nos92mx3** » July 21st, 2007, 7:44 pm

what size downpipe and exhaust?

Nomad_69er · Post by **Nomad_69er** » July 23rd, 2007, 12:32 pm

I'm running a 2.5" downpipe with a 2.5" exhaust all the way back with no cat, just a resonator. It's not detonating though which would make me think that the fuel managment that I'm running is doing ok.

mazdax3speed · Post by **mazdax3speed** » July 23rd, 2007, 2:20 pm

where is your boost gauge hooked up and what brand are you using? most gauges read a little higher, and depeneding on what source you used that could throw it off too.

nos92mx3 · Post by **nos92mx3** » July 25th, 2007, 4:23 pm

your pushing 10+ lbs because of the larger exhaust, its not detonating?
hell Run the 10 + and be happy.

rebel2k4 · Post by **rebel2k4** » July 26th, 2007, 11:16 am

cyclonekid78 wrote:If you have the Factory bypass valve you are ok. ( assuming you have a factory turbo swap) But the turbo needs a vacuum to open the wastegate.

huh? First off. boost opens the wastegate, not vacuum.

cyclonekid78 wrote: That is what a Bypass valve or boost controller is for. If you don't have these you can never stabilize your turbos boost levels. There for thats why your boost goes so high. You might want to do some more research so as not to blow up your engine. Im not trying to be a a-- here just looking out.

Bypass valve and boost controller are two different things. a bypass valve is mandatory whether you have a boost controller or not. It opens on a vacuum and releases pressurised air between the turbo compressor wheel and the throttle body to avoid backspin which can destroy the turbo.

Boost controller intercepts the boost signal to the wastegate, restricting or delayed it, thus allowing more exhaust into the turbine to spin the turbo faster and create more boost. they arent the same and should not be referred to as such. if he has no boost controller, then he should be pushing the wastegate factory boost which is 7 psi.

I would start by checking the hose going from the turbo compressor nipple to the wastegate. make sure theres no cracks or cuts in it.