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Author Topic: Tighter wastegates  (Read 29244 times)
vdubnation
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« on: August 20, 2013, 08:58:36 AM »

Why do people run tighter wastegates?
Whats the benefit of running a 20psi wastegate have been seeing more and more lately.
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majorahole
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« Reply #1 on: August 20, 2013, 09:31:38 AM »

Why do people run tighter wastegates?
Whats the benefit of running a 20psi wastegate have been seeing more and more lately.

are you talking about tightening a wastegate, or running a different wastegate with a higher cracking pressure?
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nyet
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« Reply #2 on: August 20, 2013, 09:42:39 AM »

Why do people run tighter wastegates?
Whats the benefit of running a 20psi wastegate have been seeing more and more lately.

There is this idea that turbos will spool faster or won't be able to hold 25 psi w/o it.

I'm not convinced this is the case yet (with K04s)
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ddillenger
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« Reply #3 on: August 20, 2013, 09:54:11 AM »

SRM K24's now come with 20psi gates. Shame, because the ones they had were excellent.

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catbed
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« Reply #4 on: August 20, 2013, 10:34:11 AM »

Higher wastegate pressures allow for more boost to be run, if the turbo can handle it. Exhaust pressure will open the gate at ~double the spring pressure of the gate. So if you have a 13lb spring in the gate, you can run up to ~26psi of boost. This only happens if the turbo can flow that much, eg not k03/k04 size turbos.

All of that is with respect to ME7 boost control. If you utilize the top port on some wastegates you can run more as boost pressure adds to spring pressure in that case.

IMO, stick with stock wastegate preload for k03/k04s as you can just use the factory PID maps from s4/rs4.
« Last Edit: August 20, 2013, 10:36:14 AM by catbed » Logged
julex
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« Reply #5 on: August 20, 2013, 10:34:59 AM »

http://nefariousmotorsports.com/forum/index.php?topic=1239.msg27166#msg27166

Look at the text in red.
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julex
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« Reply #6 on: August 20, 2013, 10:36:06 AM »

Higher wastegate pressures allow for more boost to be run, if the turbo can handle it. Exhaust pressure will open the gate at ~double the spring pressure of the gate. So if you have a 13lb spring in the gate, you can run up to ~26psi of boost.

All of that is with respect to ME7 boost control. If you utilize the top port on some wastegates you can run more as boost pressure adds to spring pressure in that case.

Kinda, that's for external wastegates. Internal have it at 3-4x the pressure due to flap being smaller.
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catbed
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« Reply #7 on: August 20, 2013, 10:37:28 AM »

Kinda, that's for external wastegates. Internal have it at 3-4x the pressure due to flap being smaller.

Yea, makes sense. I would assume the lever arm on the flap has some effect on cracking pressure as well.
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ddillenger
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« Reply #8 on: August 20, 2013, 10:42:57 AM »

This all jives with my understanding as well. With that said, WHY would anyone want 20psi internal gates? Apparently the SRM K24s are getting outfitted with 20psi actuators (despite the old ones being some of the best I've seen). I don't get the logic. How do you have a working PID (without the 5120) with 20lb springs? Seems awfully shortsighted. Especially considering some people MIGHT want to run stage3- for a while, or be able to modulate boost under the cracking pressure.
« Last Edit: August 20, 2013, 05:06:28 PM by ddillenger » Logged

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nyet
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« Reply #9 on: August 20, 2013, 10:45:41 AM »

This all jives with my understanding as well. With that said, WHY would anyone want 20psi internal gates?

Because pro tuner racecar
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userpike
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« Reply #10 on: August 20, 2013, 11:41:36 AM »

I think the use of higher WG opening presure is because people used to do that back when boost wasn't being controlled electronically and only via vacuum. Now with the ECU, we can adjust it how we see fit and don't have to try to have high WG open pressure to get high boost because the computer can just have a solenoid do it for us. Something that only cranking down on a WG spring could do back in the day.
« Last Edit: August 20, 2013, 11:55:55 AM by userpike » Logged
vdubnation
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« Reply #11 on: August 20, 2013, 11:54:03 AM »

WHY would anyone want 20psi internal gates? ETG (J-fonz) in their infinite wisdom has recommended 20psi gates on the SRM K24

Must be something they think is going to catch peoples attention in buying for people who dont know who knows Maybe they think its cool or something lol.
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NOTORIOUS VR
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« Reply #12 on: August 20, 2013, 04:13:07 PM »

What did the SRM turbo have before for cracking pressure?

and just so we're all on the same page here.. the OP was asking about tighter WG's... that isn't the same as having a different spring in the WG itself.
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nyet
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« Reply #13 on: August 20, 2013, 04:28:16 PM »

What did the SRM turbo have before for cracking pressure?
I'd like to know this too

Quote
and just so we're all on the same page here.. the OP was asking about tighter WG's... that isn't the same as having a different spring in the WG itself.

Very true, but with the limited amount of space in the stock internal wastegate location, they practically amount to the same thing, because no amount of preload games are going to fix things w/o a completely different WG setup in a different location.
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ddillenger
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« Reply #14 on: August 20, 2013, 04:55:11 PM »

They're advertised (or not, but spec'd) at 10psi. The first set I experienced were shipped and verified at 6psi, then adjusted to 10. The logs above had the gates verified at 10-11.
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