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Another little story of weird shit happening

GTSBoy
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GTSBoy Grand Master

GTSBoy

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Early last week, I became concerned that the car was feeling....slow. Most of my driving is commuting to/from work and there are few opportunities to get up it and convincingly make boost/power. It drives in vacuum almost all the time. But when you do occasionally get an opportunity, and.... it takes a little longer to start making power, and then there's not as much as you'd expect, and then you run out of road anyway and have to bottle out - it can be hard to be convinced that there's something wrong.

But by the end of the week I was pretty convinced. Made an effort to get a decent test run. Took bloody forever to come up on boost and when it did it would only make about 50 kPa of pressure.

There was no black smoke, no noise of a boost or exhaust leak, no evidence anywhere of an intercooler hose clamp being sloppy enough to let air escape. So.... not that sort of problem.

Brainstorming led to thinking that the boost controller's solenoid might have failed in some way. No active boost control would just give wastegate pressure, which I was more or less getting, and the laggy behaviour could just be "normal" shitty boost response from an uncontrolled highflow. But a little extra 3rd party brainstorming led to the thought that the actuator circlip might have jumped off leaving me with a bluetooth wastegate.

So, on Friday, off comes the stock heatshield (which is an annoying enough job on its own) to reveal - yup. WG is wide open. And.... it won't come back. It is jammed in the dump.

Put the rod back on with a new circlip and tried driving it to get it hot in the hope that the capture was from thermal effects having been blown into the dump when hot and since cooled. Nope. Won't move, even with screwdriver mediated force when hot.

Ran out of time to play. Came back to it yesterday. Unbolted the dump. Was lying under it with the dump jammed up against my guts undoing the bottom 2 bolts. Got them most of the way out and gave the dump a serious heave. It didn't noticeably move, but there was a satisfying "plink" noise from up top. Shuffle out and sure enough, gate is now closed.

Nevermind that there was still the better part of an hour after that required to put it all back together. f**ken cars.

Lithium Grand Master

Lithium

Posted
Posted (edited)

Ahh one of my favourite things :D Have experienced that with a couple of aftermarket IWG turbo setups, a hint is (usually?) the exhaust gets a bit rowdier/tinnier under normal driving around as you've effectively lost a muffler you usually have operating when you're lurking around off boost.   

When I do road trips in my BMW I often (don't tell anyone I do this...) run it in Eco-Pro mode which turns out to open the wastegate at cruise to keep it working as an NA and maybe a little less pumping loss by having the exhaust have an easier path, never noticed that this is what was happening until I upgraded my dump pipe and starting thinking "Why is my car sounding a bit like it's got an exhaust leak now?" - only to find it go away when I run it in any other mode.  

Time to go external gate ;)

Edited by Lithium
GTSBoy Grand Master

GTSBoy

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5 minutes ago, Lithium said:

the exhaust gets a bit rowdier/tinnier under normal driving around as you've effectively lost a muffler you usually have operating when you're lurking around off boost. 

Yes - at ~2500-2700 rpm (ie, about 100-110) it was barking a bit. But I've heard that before. Makes me wonder if I haven't captured the flapper open in the past, but with the circlip still in place it rectified itself. More than once.

Lithium Grand Master

Lithium

Posted
Posted
4 minutes ago, GTSBoy said:

Yes - at ~2500-2700 rpm (ie, about 100-110) it was barking a bit. But I've heard that before. Makes me wonder if I haven't captured the flapper open in the past, but with the circlip still in place it rectified itself. More than once.

Ahh yeah, probably not too surprising - nice catch anyway, aside from being a bit of a pain.  I think we've done a bit of wrestling and grinding to make sure all is aligned and clearanced nicely if it seems like a potential ongoing problem.

GTSBoy Grand Master

GTSBoy

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Still haven't put the injectors and R35 AFM in so we can tune the bloody thing for the HG highflow it got mid last year! I think I can forecast the upgrade path to a bigger twin scroll, external gate, Haltech, flex setup, Samsonas, dis dat, etc will be .... a while away!

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GTSBoy Grand Master

GTSBoy

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1 hour ago, luke gtr said:

At least you're now aware of the problem and can come up with a solution. 

 

1 hour ago, Duncan said:

Now you should better understand the pain our NA brothers and sisters (and themsters) feel every day.

 

43 minutes ago, Dose Pipe Sutututu said:

New turbo setup required, 400kW or go home.

I think, given the usage model described in the OP, I'd never ever experience the wonders of the 400kW upgrade. What I really need is boost from 2000rpm and probably no more than 260-270rwkW. But I suspect that the highflow is not actually the turbo for that purpose, so I may in fact need to get a G25 or 30 or something right sized and very spooly. We shall see after it is tuned. I've had to back the boost and boost ramp off to stop the thing from pinging since the highflow went on, so I've been almost living the NA life for 9 months now!

Injectors are recently in hand. AFM is in hand. Dyno is fixed. Just need to clear a queue of f**king Supras out of the way (and probably fit my new gearbox). So....some time this year? Lol.

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GTSBoy Grand Master

GTSBoy

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14 minutes ago, MBS206 said:

TT LS3?

Hmm. Prefer blower on that one.

14 minutes ago, MBS206 said:

Or NZ V12 TT...

Preaching to the choir. But without the TT. Ima think NA V12 trumpet noises would keep me happy.

But seriously, no matter how much I try to convince others to be bold and do the above swaps, I'm not too likely to do it on my daily! I'm not insane.

MBS206 Grand Master

MBS206

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2 minutes ago, GTSBoy said:

Hmm. Prefer blower on that one.

Preaching to the choir. But without the TT. Ima think NA V12 trumpet noises would keep me happy.

But seriously, no matter how much I try to convince others to be bold and do the above swaps, I'm not too likely to do it on my daily! I'm not insane.

Buy a new daily... Do swap on old daily.

Sell new daily.

hypergear Grand Master

hypergear

Posted
Posted

In many cases, aftermarket dump pipe inlet flanges don't properly align with the outlet of the turbine housing, as they were designed to fit within the constraints of a 3-inch pipe. When an oversized wastegate flapper valve is installed, it can interfere with the dump pipe flange. A bit of die-grinding usually resolves this issue. Additionally, the actuator must be preloaded, otherwise, the flapper valve may rattle. The stock wastegate also tends to open too early, so upgrading to a wastegate actuator with a stiffer spring can improve boost response.

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tylink720 Contributor

tylink720

Posted
Posted
On 27/04/2025 at 10:30 PM, Lithium said:

When I do road trips in my BMW I often (don't tell anyone I do this...) run it in Eco-Pro mode which turns out to open the wastegate at cruise 

I've always wondered why my brothers BMW is louder in Eco mode. Do they have e-gates from factory?

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