Disappointed With My Boost Control

[BGGSTin]

Well my mods are in the profile, but I have an AVC-R with TIAL 38mm Wastegate and Ported Evo 3. Now I recently got my car tuned by Slowboy's and we only ran the car to 6000 because after that it started to creep oncontrollably. Well the other day I was running the car and my boost crept to 1.73 bar. [Yeah 1.73 bar = ~25.5psi ] I mean its not horrible, but stock internals and the fact its my daily driver, makes me care for things like this. For now, I'm just not going to take it that high. Heres a more detailed explanation though, cars at 16psi around 4000 or so, creeps from there up to 21 by 6000 then keeps going to the greatest so far of 25 psi. At 6000 it feels like it pull steady, but right after 6000 it damn near feels and sounds like it hits vtec [shutup honda haters, it does]. Now this was with the AVC-R off and just using my spring pressure in the wastegate, so maybe it was just fully opening the wastegate after 6000?
I'm selling the AVC-R though, from mine and Slowboy's thoughts and getting an MBC. When we put the car on the dyno the torque was crap for what it should have been. The curve went normally until 3000rpm then it platued and didn't rise again until 6000 which is where it also hit max. I guess I'm just wondering is it expected to have it creep this high? It definitely regulates it at 1bar until 6000, so are the gasses outflowing the wastegate at that point since it's a 38mm?
I'll try to tune the AVCR to 21 psi all time and see if that makes the car run better today. My peak HP was at 21 so maybe instead of letting it creep from 16 to there. I'll try to get it to just stay at ~20 or so, just as long as it doesn't repeat the previous pattern of creeping like it did from 16 at 20
Any thoughts are appreciated

 

[mostapasta]

Try putting the external wastegate off the manifold or port the wastegate passage of your turbo more.

 

[BGGSTin]

I think it's just mainly due to the AVC-R, whatever, if my engine blows it's back to slowboys for either a stroker longblock or just a 2.0 longblock, then I can put down some real power. Prob. go 50 trim then too
I'll just try changing some AVC-R settings, theres just too many, that's my only gripe about it.

 

[Talesin]

For a lot of people, there's a reason beyond money to stick with a $20 spring and ball MBC, than a $300 bit of cockpit eye-candy.

 

[XakEp]

The only thing between a healthy motor and a blown motor is a ball and spring if youre using a MBC. Works for some, the rest of us prefer a little peace of mind. I personally used MBCs for 4 years before I tossed it in and got a turbosmart E-Boost. Never looked back. If youre going to get an EBC, get the best. That AVC-R is shite.

 

[oldman]

Well my mods are in the profile, but I have an AVC-R with TIAL 38mm Wastegate and Ported Evo 3.

Whom and how was it ported? Where is the wastegate mounted? Manifold or O2?

 

[BGGSTin]

Ported exhaust turbine by Slowboy's and it's an O2 mounted external wastegate.

 

[oldman]

Ported exhaust turbine by Slowboy's and it's an O2 mounted external wastegate.

Just as I thought, nothing against SBR's ability to port but most turbo vendor port jobs mainly consists of port matching to 7cm and doesn't address boost creep. This is what you can do.

1. Re-mount the wastegate on the manifold, preferably near the collector. This will however create other problems for you, assuming you don't have a flapper on the turbo.

2. Re-port the turbine housing inlet exactly like the tech article I linked you, The person whom wrote that article also started with a SBR ported EVO3. In addition, enlarge the wastegate path as much as you can since you don't have to worry about flapper sealing. Read through that article, if you decide to go for it, asked questions before you start because it has to be done right or it won't work.

Good luck.

 

[oldman]

BTW Boost controller will not cause or fix boost creep. To check this, bypass the avcr and connect a pressure source directly to the gate. If you truly were creeping, you should creep even worse now.

 

[Mackzero]

The AVC-R should definitely NOT be your problem. A MBC is a piece of crap compared to the AVC-R. I will NEVER go MBC after having a good EBC, I run the E-01 from Greddy and could not be happier. The Tial 38mm should easily be able to regulate your boost on that turbo.

Also, What size of spring is in it???

Check your gaskets, and your boost hoses to the EBCs solenoid, then to the wastegate, and DO NOT use that colored hose crap people sell to "dress up" the engine bay, it is garbage. Get some good strong hose for that, and make sure to use clamps.

 

[BGGSTin]

Alright, Friday night the gasket between my O2housing and wastegate felt the need to discintegrate. So... Saturday I went up to Slowboys, picked up my clutch and gasket. Now, I havn't checked to see yet if I still have a creep issue, but it may have just been that my gasket was going, because I had seen some carbon at the corner and knew it was going to go soon. Anyways, I've been running it for the past couple of days, once I get home and double check tightness, I'll see if it still creeps.
Sounds plausible that it was the gasket letting out exhaust when the pressure built too high from the exhaust at high rpm's; this was taking away the restrictions of the wastegate regulating, by bypassing it; allowing the boost to jump uncontrollably.
I wanted to stop at PRP on the way back to finally see what I can run (with a not so great clutch, since I won't have time to put on the 3500 by then) but I guess I'll have to wait until this weekend (since I had to use the truck to drive up there since my gasket fried ) to see; if it's nice out...