Jump to content
SAU Community

Pros And Cons Of Wastegate Feed Positions

zebra

By zebra,
in Engines & Forced Induction

 Share

Recommended Posts

bradsm87 Proficient

bradsm87

Posted
Posted

stretching them the other way to the direction they're designed to go, wearing them out quicker. The dodgiest bit is at 60-90% throttle tho. The wastegate thinks the turbo's only producing 10psi so closes right up, meanwhile the turbo could be pushing 25psi before the throttle body. U can hear it as u back off a bit. Dodgy imo.

rob82 Mentor

rob82

Posted
Posted

Using a vacuum reference is a really shit idea - not only are you causing a vacuum leak as you bleed the solenoid onto boost but your also applying negative pressure on the actuator meaning that its more likely to open the wastegate flap so it will make the car slower onto boost. Not only this but if gases are escaping out of the the wastegate port then your putting more thermal loading on wastegeate port - guess where turbos are likely to crack!!

zebra Grand Master

zebra

Posted
  • Author
Posted

how is vacuum gonna hurt them?

This is what i would like to know too.

Like I said before, I had the same setup on my Gtst with no dramas, the whole point of this exersise is to hold the wastegates shut for as long as possible, not constantly bleeding off exhaust gas.

  • 8 years later...
BK Grand Master

BK

Posted
Posted

ok I'm bumping this.

Boost pressure source for wastegate / boost solenoid - plenum or compressor housing ?

I've always been plenum, but seeing all of the Precision / Borg Warner / Garrett singles now with nipples on the compressor housings is making me think twice, especially since I've moved to a 6466.

Surely plenum is the go as that is what the engine is seeing and what you want to control ? So why have compressor nipples then ?

I am talking RB26 here so I do realise pressure source always has to be before the throttles (like the plenum), unlike a 25 where the plenum is after the single throttle body making the plenum a no go in that situation.

GTSBoy Grand Master

GTSBoy

Posted
Posted

There is no difference between plenum and comp housing on an ITB 26.......well, there is a small difference related to the speed of sound and the propagation rate of the pressure signal. I think Nissan did it in the plenum on the 26 because it was a reasonable place to pick up a signal from both turbos. That's all.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing


  • Similar Content

  • Latest Posts

    • GTSBoy
      Mistakes were made, my R34 Story

      By GTSBoy · Posted

      I myself AM TOTALLY UNPREPARED TO BELIEVE that the load is higher on the track than on the dyno. If it is not happening on the dyno, I cannot see it happening on the track. The difference you are seeing is because it is hot on the track, and I am pretty sure your tuner is not belting the crap out of it on teh dyno when it starts to get hot. The only way that being hot on the track can lead to real ping, that I can think of, is if you are getting more oil (from mist in the inlet tract, or going up past the oil control rings) reducing the effective octane rating of the fuel and causing ping that way. Yeah, nah. Look at this graph which I will helpfully show you zoomed back in. As an engineer, I look at the difference in viscocity at (in your case, 125°C) and say "they're all the same number". Even though those lines are not completely collapsed down onto each other, the oil grades you are talking about (40, 50 and 60) are teh top three lines (150, 220 and 320) and as far as I am concerned, there is not enough difference between them at that temperature to be meaningful. The viscosity of 60 at 125°C is teh same as 40 at 100°C. You should not operate it under high load at high temperature. That is purely because the only way they can achieve their emissions numbers is with thin-arse oil in it, so they have to tell you to put thin oil in it for the street. They know that no-one can drive the car & engine hard enough on the street to reach the operating regime that demands the actual correct oil that the engine needs on the track. And so they tell you to put that oil in for the track. Find a way to get more air into it, or, more likely, out of it. Or add a water spray for when it's hot. Or something.   As to the leak --- a small leak that cannot cause near catastrophic volume loss in a few seconds cannot cause a low pressure condition in the engine. If the leak is large enough to drop oil pressure, then you will only get one or two shots at it before the sump is drained.
    • GTSBoy
      Help! Leak coming under transmission

      By GTSBoy · Posted

      So..... it's going to be a heater hose or other coolant hose at the rear of the head/plenum. Or it's going to be one of the welch plugs on the back of the motor, which is a motor out thing to fix.
    • MBS206
      Mistakes were made, my R34 Story

      By MBS206 · Posted

      The oil pressure sensor for logging, does it happen to be the one that was slowly breaking out of the oil block? If it is,I would be ignoring your logs. You had a leak at the sensor which would mean it can't read accurately. It's a small hole at the sensor, and you had a small hole just before it, meaning you could have lost significant pressure reading.   As for brakes, if it's just fluid getting old, you won't necessarily end up with air sitting in the line. Bleed a shit tonne of fluid through so you effectively replace it and go again. Oh and, pay close attention to the pressure gauge while on track!
    • Kinkstaah
      Mistakes were made, my R34 Story

      By Kinkstaah · Posted

      I don't know it is due to that. It could just be due to load on track being more than a dyno. But it would be nice to rule it out. We're talking a fraction of a second of pulling ~1 degree of timing. So it's not a lot, but I'd rather it be 0... Thicker oil isn't really a "bandaid" if it's oil that is going to run at 125C, is it? It will be thicker at 100 and thus at 125, where the 40 weight may not be as thick as one may like for that use. I already have a big pump that has been ported. They (They in this instance being the guy that built my heads) port them so they flow more at lower RPM but have a bypass spring that I believe is ~70psi. I have seen 70psi of oil pressure up top in the past, before I knew I had this leak. I have a 25 row oil cooler that takes up all the space in the driver side guard. It is interesting that GM themselves recommend 0-30 oil for their Vette applications. Unless you take it to the track where the official word is to put 20-50w oil in there, then take that back out after your track day is done and return to 0-30.
    • PranK
      My new to me M35 Stagea wagon

      By PranK · Posted

      Nice, looks great. Nice work getting the factory parts also. Never know when you'll need them.
×
×
  • Create New...