Not Holding High Boost, Any Ideas?

[HYBR3D]

Hey all, I used my high boost today for the first time in a while, Usually I run 15 psi as my high setting but I felt like opening her up a little so I ran 23 psi. I came into 3rd then boosted all the way through the gear, nothing out of the ordinary.

Heres the problem, Car got up to 1.5 bar, then once hit it, it dropped down to 1 bar or so then back up to 1.5 and so on repetitively. So its not very stable to say the least. But when I run 1 bar as max boost like usual its always 100% stable.

I am using the Blitz SBC ID controller and im pretty confident its hooked up right. (Solenoid tapped into the hose that goes to the black cannister by headlight)

The controller is reading directly from the plenum.

Could it be possible the standard R32 GTST bov cant hold that sort of pressure and is leaking? Or should the solenoid have its own direct connection? I can understand it being unstable with a couple psi but a whole 7 psi fluxuating is pretty crazy

Any ideas anyone?

Cheers all

[SargeRX8]

What turbo? What ecu? i'm going to say either the bov is not holding (blank it off and see), you have a boost leak, your ebc is hitting the limiter and cutting off boost. Does it flop the moment you hit more boost? Why the hell are you using a line from the carbon canister?

Tee into your hot pipe.

[JDMKiD__/ⓞⓞ-33]

I had a similar problem.

I boosted from 10psi to 15psi and it would reach 15 then as i progressed thru revs is dropped down to 10 again.

It was my wastegate lol

[hypergear]

Sounds like too much back presure. need a larger housing, or larger turbine wheel or stronger actuator.

[HYBR3D]

Garrett turbo, apexi fc ecu, has been tuned on the boost by previous owner. I don't remember it doing this in the past tho I don't usually hold boost through out gears as long.

It's hooked up that way because that's how the mechanic did it and how it was when I brought the car.

Shouldn't be any back pressure, it was tuned on setup and it iis a Garrett gt2871

Yea pretty much just flopped once it got to the boost setting.

Where's this hot pipe? Everything's running from the plenum

Edited February 20, 2012 by HYBR3D

[hypergear]

yea 2871 on a rb20 will do that 100%. on a .64 rear housing as well?

[The Mafia]

Did you ever consider that the turbo might not be setup for that kind of boost?

[SargeRX8]

2871 running +23psi... ME GUSTA

[HYBR3D]

Where do you guys recconeng getting the boost source from? I thing I need to sort my vacuum lines out

[HYBR3D]

Well played around with the controller this morning and it's now sitting at 1.45 bar stable as. Think the warning needed changing. You guys are right tho it is a little high for the small thing but nuthing it can't handle

[DVS JEZ]

Was gonna say check the over boost warning

[The Mafia]

You guys are right tho it is a little high for the small thing but nuthing it can't handle

You'll be eating those words when the super heated air caused by running the turbo beyond its efficiency range causes the engine to detonate and blows the ring lands off most of your pistons.

[HYBR3D]

Should be fine it has a massive blitz intercooler, and the engine is all forged with all supporting mods.

See what happens I think it will be fine. Either way it's going for another tune shortley. Thanks for the help everyone.

Edited February 20, 2012 by HYBR3D

[The Mafia]

Should be fine it has a massive blitz intercooler, and the engine is all forged with all supporting mods.

See what happens I think it will be fine. Either way it's going for another tune shortley. Thanks for the help everyone.

That's not how it works hey.

You'll find if you bring the turbo back to an amount of boost where it is at its best efficiency, it will lose very little horsepower, and might even gain some.

Also, a "big" inter-cooler certainly does not counteract the effects of the turbo super heating the air due to inefficiency.

You really need to read up on how they actually work.

There are a lot of people out there that think boost is actually good.... Boost is bad.. Flow is good..

[HYBR3D]

That's not how it works hey.

You'll find if you bring the turbo back to an amount of boost where it is at its best efficiency, it will lose very little horsepower, and might even gain some.

Also, a "big" inter-cooler certainly does not counteract the effects of the turbo super heating the air due to inefficiency.

You really need to read up on how they actually work.

There are a lot of people out there that think boost is actually good.... Boost is bad.. Flow is good..

Yea your completley right I won't argue with that. The thing is I don't want to upgrade anything in this setup and I want to achieve the most out I what I have.

The only reason I'm using 1.5 bar is because that's what it's been dynod to already so I'm assuming it's as efficient as it can be there. I'm only re tuning because I have upgrade fuel pump as it was the only thng letting it down last time.

[SargeRX8]

Forged motor and such a tiny turbo. Also read my initial post, I told you it was an ebc warning