Boost Issue Troubleshooting

[Rolls]

im having a mental blank to explain it in detail, but retarding the ignition timing increases the exhaust temperature and hotter egt's cause the turbo's to spool faster

Yep that's what I said.

[Trozzle]

DVS32R, yeah that's correct due to the mixture burning later in the power cycle, hence less time to cool before leaving the cylinder.

Also Stao, yeah he was deliberately keeping power low up top to conserve the engine. I agreed with this choice. This tune is somewhat mild all over though for the same reason.

[Harey]

The only way to decrease the forces acting against the wastegate+actuator is to either let off the throttle, or somehow restrict the pressure acting against the actuator. This is where a boost controller comes in.

In my scenario, adding a boost controller only increases boost between 4,000-5,000rpm after that it drops to the same level. This means that even with the actuator receiving almost no boost signal (boost controller) the wastegate flow is still pushing the wastegate flapper open and overpowering the actuator spring.

[Harey]

Also Stao, yeah he was deliberately keeping power low up top to conserve the engine. I agreed with this choice. This tune is somewhat mild all over though for the same reason.

My thinking at the moment is whats the point in having these large turbos and then restricting them to 280-290rwkw. We would be better off with more responsive turbos that still make 280-290rwkw peak.

The latest 3071 0.82 result from Hektik is excellent, full boost at 3600rpm and still makes 280rwkw.

[Trozzle]

Well I'll end up pushing the turbo into it's correct comfort zone when I get back from Europe later in the year....then when my engine goes pop, I'll be able to keep using it. For now, it's still perfectly good for what it's doing.

[Ultimategtr]

Hi,

Did some search and decided to revive this thread. I am having boost creep. Its a hybrid R33 turbo with HT18 exhaust setup and bored out comp housing etc.

On the dyno it was creeping badly just off the w/g actuator, from say 8psi through to 18psi(very bad eh). The tuner used the Link G4 Boost controller to settle it around 16psi max creep.

I currently am using the stock actuator - 7psi. I realised that might be the issue? Trying to get a solid 16psi. On the dyno she made 275kw @ 17-18psi, but that was with the creep.

On the road its like this - 2nd gear.. I get 7psi instantly, but it starts to creep around 5k. All I want is a solid 16psi roughly from 3500-4000rpm. I have a feeling it may be the actuator thats the problem though.

I'm picking up an R32 actuator this sunday to see whether that helps(10psi). Any thoughts in my situation?

[scotty nm35]

A stiffer actuator wont help the wastegate flow more which is what you need when boost spikes. Perhaps you can grind the hole bigger but then you will definitely need the larger actuator.

[Ultimategtr]

I can get that done no worries. Im assuming that at around 5k, the exh gases are causing the flapper to close due to the weak 7psi spring.

Its so frustrating on the road, it feels like driving a big laggy turbo, lol.

[Rolls]

If it is creeping with a weak spring a stronger spring will help you get on boost sooner but it may still creep up even higher.

Sounds like the internal wastegate simply isn't big enough.

[Ultimategtr]

Maybe, the guy that did my turbo has never had to to dremmel the port out, so maybe it is the w/g actuator, but Ill see I guess this weekend.