Is it true? Better boost response....

[Guest bastaad525]

Is it true that a stock T3 will give better response if I block off the two ports on the compressor housing and instead run a hose from the intake manifold to the wastegate actuator? If so, why is that?

 

Would it matter if the vacuum line was teed off? The reason I ask is I'm out of vacuum ports on my manifold. There are only four, and I am using them for: BOV, Boost Gauge, FPR, Brake booster. I was figuring I could put a tee in the port I use for the BOV, and run the BOV and WG actuator off that... would that create any problems?

 

Keep in mind that I'm using one of the DIY MBC's... if that would make any difference in hooking up the WG actuator this way.

[Cody 82 ZXT]

You would want to tee off your BOV and your FPR. If your going to use a vacuum source from the intake then you would want it to have it's own line. The reason this will give alittle better response is due to the fact that it will take alittle longer for the intake to pressurise vs. the time it takes for the compressor housing to pressurise. This small difference in time will let the turbo spool slightly higher for a momet and let the boost spike above it's setting. It does work and you should feel the differnce but, in my opinion it is a good way to hurt parts in a system that is not tuned to have a boost spike like that. If your system has enough headroom for the added boost (fuel) them it shouldn't be a proublem.

[Guest bastaad525]

ah no then I dont think it'd benefit me... I get the same effect from the grainger MBC. Basically it keeps the pressure off of the WG diaphram completely, up until your target boost is reached, and causes a little bit of a spike (1psi) before opening and letting the boost get to the WGA. I did notice a bit of a difference in the spool time with this MBC. I'll tell you one thing... I am now a 100% believer in needing 3" mandrel bent exhaust and better DP... I remember how incredibly fast the turbo used to spool with the open DP... now with the crappy crush bent 2.5" there lag, even when flooring it above 3000rpm... it's much slower spooling up. The MBC helps this... but not enough Anyway I may still try running the feed from the intake just to see if it works better over feeding from the two nipples on the turbo... dont think I'd want any more spiking though.

[CU Zcar]

I had this discussion with a friend who found his Mazdaspeed Protege controlled the turbo with manifold pressure vs. compressor outlet pressure. We decided that running the wastegate off manifold pressure was probably a good idea because there are conditions when manifold pressure is lower than compressor outlet pressure (i.e. when the throttle is only partially open or shut) but it might still be desirable to have the turbo spooling vs. having the wastegate open. We were also thinking about when you shift, the manifold is under vacuum and that should keep the wastegate shut during the shift, maybe helping the turbo to keep spooled just a bit. I'd need to install a BOV to benefit probably (still running w/o one) but his car of course has one (well, a CBV anyway).

Did that make any sense?

[awd92gsx]

Running an electronic boost controller was the best way I found to help minimize lag/reduce spikes.

 

Any turbo car should have AT LEAST a 3" exhaust. You can't have too large of an exhaust for a turbo'd car.

 

I personally enjoyed running more timing and slightly less boost than running less timing and more boost...it seemed to help with the low/midrange boost.