Jump to content
SAU Community

Gt3076r Not Holding Boost

limpus

By limpus,
in Engines & Forced Induction

 Share

Recommended Posts

limpus Mentor

limpus

Posted
Posted

Hey guys,

I'm having a problem with holding boost properly with my garrett 3076r...its ramping up to 21psi but then tapering off to 18psi above 5000rpm...i'd ideally like to have it hold 21psi across the rev range...

Setup is a little different though...

Toyota Supra

2JZ-GTE

Custom low mount manifold

Garrett 3076R 56T 0.82 IW with Garrett big can 18psi actuator (preload is set right and its achieving 17-18psi with the boost controller off)

4" intake pipe

Sard 280LPH fuel pump

FMIC

3" exhaust

PFC

AVCR

I've had the car on the dyno twice trying to get proper boost control but i can't stop the boost from falling off...the rb30det boys suggested using the 18psi actuator which i've got and its still not doing it...the boost curve looks almost idetical with the old smaller 14psi actuator and the bigger 18psi one...its still ramping up very well and 20psi is achieved by about 3300rpm...but then it justs falls off by 5000+rpm...i've tried tweaking the AVCR with numerous different settings and all it does is cause boost to ramp higher (23-25psi) before falling back to 18psi again...

Does anyone have any input on this...note that external wastegate is not a valid response... :P

Link to comment
https://www.sau.com.au/forums/topic/342146-gt3076r-not-holding-boost/
Share on other sites
  • Replies 62
  • Created
  • Last Reply

Top Posters In This Topic

Popular Days

Top Posters In This Topic

Popular Days

Posted Images

Trozzle Grand Master

Trozzle

Posted
Posted

Why do I want to derail this thread SO BADLY?

Looks like your Genuine Garrett item is no better than the Hypergear item you spent so much time badmouthing.

Although to add a relevant response, since I haven't seen results of this turbo at that boost on a 3L....what are the chances it's either running out of puff, or that the exhaust flow from 3L engine against the wastegate on top of the boost pressure against the actuator are causing it to not hold closed as much as desired? I know that last situation isn't likely, but perhaps it just can't flow what your engine wants to swallow.

Lithium Grand Master

Lithium

Posted
Posted
Looks like your Genuine Garrett item is a lot better than the Hypergear item you spent so much time badmouthing.

Fixed. We know the GT3076Rs spool faster than a 300+kw Hypergear turbo, and here it is holding similar boost on a 2JZGTE as what the Hypergear does on an RB25... its clearly able to pump some air to do that.

I'd say however that at that boost level its a good chance that its just maxing out, its not that large a turbo for a decent flowing 3litre - how much power are you getting out of it at that boost level?

Trozzle Grand Master

Trozzle

Posted
Posted
Fixed. We know the GT3076Rs spool faster than a 300+kw Hypergear turbo, and here it is holding similar boost on a 2JZGTE as what the Hypergear does on an RB25... its clearly able to pump some air to do that.

I'd say however that at that boost level its a good chance that its just maxing out, its not that large a turbo for a decent flowing 3litre - how much power are you getting out of it at that boost level?

I fail to see how that's any more correct than my obvious troll post, given his above posted results.

SimonR32 Grand Master

SimonR32

Posted
Posted (edited)
Fixed. We know the GT3076Rs spool faster than a 300+kw Hypergear turbo, and here it is holding similar boost on a 2JZGTE as what the Hypergear does on an RB25... its clearly able to pump some air to do that.

STATUS posted a Hypergear vs 3071R graph a few days ago which would say different. They were for all intensive purposes identical spool... Unless you are going to claim a 3076R will spool faster than a 3071R?

Edited by SimonR32
hypergear Grand Master

hypergear

Posted
Posted

:ninja: I give you some advise either way.

I've managed to hold 22psi on a RB30det VL, of a customer's car. Needs custom made twin spring actuator with gate controller. If you really want to stick with Garrett Actuators try: 446131-23 .

If that doesn't work, send in your turbine housing for modifications. Which I will charge you a million dollars :) .

Lithium Grand Master

Lithium

Posted
Posted

Trozzle - I added 2c in regards to why it COULD be boost dropping... when I chose a GT3076R for my RB25 I was aiming for a setup which could flow efficiently enough to push around 22psi of boost into a 2.5litre up to 7000rpm without being silly about it. To do the same on a 3litre I'd personally be looking at using something more like a GT3582R, so really I'd expect the required solenoid duty cycle to maintain 22psi or so in the higher revs to go WAY up when used on a 3litre in higher revs as IMHO the turbo will start hitting its flow limits.

Other obvious things to check would be if there are any leaks, either exhaust or intake side. Also, I am not convinced on AVC-Rs at all... when I had the softer actuator on mine I couldn't convince it to bring it anywhere near strong enough onto full boost, I had to upgrade to an 18psi big can unit.

Its doing the same things the Hypergear turbos which were used to crack 300kw were doing on RB25s... if you don't quite understand that "boost" isn't a universal thing, what this means is that if you put the 300kw Hypergear turbo onto the larger 2JZGTE and this IS what the problem is - there is a good chance you'd see full boost reached slightly later than the GT3076R, but then boost dropping earlier again and a net result of less hp in the top end.

STATUS posted a Hypergear vs 3071R graph a few days ago which would say different. They were for all intensive purposes identical spool... Unless you are going to claim a 3076R will spool faster than a 3071R?

I gave up following the Hypergear threads after there were "not all being equal" factors used too consistantly which could skew things to make it seem the Hypergear was better in comparison than it really was, so not sure exactly what was shown and as such can't really comment. I'm not one eyed or stupid and also don't try and pull the wool over peoples eyes so don't see why you are implying I would suggest a GT3076R would spool better than a GT3071R, keep that brush on the people who do that kind of thing.

limpus Mentor

limpus

Posted
  • Author
Posted

To all the haters...you can say whatever you want regarding this...i've said my piece the other turbos and i stand by it...feel free to keep spouting crap...i've long stood by the motto that you should only dish it out if you can take it...

I chose this turbo because other RB30DET members on here have gotten good results on their cars with this setup...and with the 18psi garrett actuator too...yes the 3076R is a tad small for a 3L...i know that...but i chose it because peak power wasn't the aim...maximum response was the aim with 300rwkw in mind...and it does that...no complaints there...also...i wanted to be the first to do a low mount single setup in victoria just to prove it could be done...and i've proven it...have a look in the RB30 thread for some examples...i'm staying out of comparisons between rb25s here as a 2JZ is a whole different kettle of fish...

WYTSKY Veteran

WYTSKY

Posted
Posted
STATUS posted a Hypergear vs 3071R graph a few days ago which would say different. They were for all intensive purposes identical spool... Unless you are going to claim a 3076R will spool faster than a 3071R?

Maybe it does? Garrett 3076r: 18psi 3000rpm

post-36975-1288226199_thumb.jpg

kwickr33 Community Regular

kwickr33

Posted
Posted
I gave up following the Hypergear threads after there were "not all being equal"

Its also not been equal that you are running on a "NZ dyno" with all the enchantments for better response. This also made you the most responsive 3076R .82 int gate through out Australia. Far better then some with cam gears and external gates. Run that on Status dyno and see what happens.

limpus Mentor

limpus

Posted
  • Author
Posted
If that doesn't work, send in your turbine housing for modifications. Which I will charge you a million dollars :) .

Since we're all joking here...if i had a million dollars...i'd start a turbo highflow service and claim a gazzzillion KW at 1000rpm...

But seriously...if you can find people with 2Js for you to trial your constant R&D and pulling off and replacing turbos on a contant basis and get the results i'm after then i might consider your products...if not...then nah...

limpus Mentor

limpus

Posted
  • Author
Posted
If peak power isn't your aim, why are you complaining about boost dropping off in the top end? Honest question.

Always going to happen with that size turbine housing on a 3L.

Well...peak power isn't the aim...area under the curve is the aim...and with consistant boost pressure i'd get more area...

The turbine housing can do it...proven here in this thread...http://www.skylinesaustralia.com/forums/Gt....html&st=20

So the issue is more likely to lie with my setup...and not my turbo...which some people seem to be wishing for... :)

hypergear Grand Master

hypergear

Posted
Posted
Since we're all joking here...if i had a million dollars...i'd start a turbo highflow service and claim a gazzzillion KW at 1000rpm...

But seriously...if you can find people with 2Js for you to trial your constant R&D and pulling off and replacing turbos on a contant basis and get the results i'm after then i might consider your products...if not...then nah...

Seriously I can really make that work and hold it at what ever "high" settings you want it to set it. even at 24psi as long as the turbo it self can take it (assume engine's won't have issues).

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

    • Erelyes
      Ceramic turbine damage to engine - what did yours do?

      By Erelyes · Posted

      Ha, well, it's been.... a bit of a journey. Things have taken much longer than I'd hoped. I'll probably put up a thread at some stage. Hopefully soon. The car's not done any kms since my update in June though, put it that way.
    • Dose Pipe Sutututu
      M35 Aftermarket Fuel Pump

      By Dose Pipe Sutututu · Posted

      Here's the chart for fuel pressure vs. current draw, assuming your base fuel pressure is 3 bar and you run like 0.5bar boost on WOT, you should only momentarily hit 9amps here and there. (Ignore my prev post, I cannot read a chart these days it seems)
    • GTSBoy
      RB25 Drama's

      By GTSBoy · Posted

      Those comp test results are not hideous. Whether they are accurate or not (ie, when that comp tester says 140 psi, is the real pressure120, 140 or 160?) is unknown to us. The state of the battery used to crank it over is unknown, etc etc. Many people around here would say that the absolute values and the spread are perfectly fine to just add boost and keep going. I personally would be happier with a narrower spread than that, but even the diff between 125 and 145 is not terrible. That one cylinder at 125 though, has probably copped some damage relative to the others. You should inspect the valves seeing as you've got it open. Do you know how to measure installed ring gaps? That, and an inspection of the rings themselves, is how you will determine whether they need to be replaced. If you're not good to do these things, take the block and the pistons and rings to a shop that is, and ask them for the go/no-go on them. Do the bores need a hone at all? If so, you might well be justified in getting some different pistons in order to get away from the ring supply problem. Whether you're happy to spend a lot more money right now, on more gear, rather than less money, but an amount that looks stupid given that you will only get a handful of rings in exchange for that money, is for you to decide.
    • iain_ST44GA
      M35 Aftermarket Fuel Pump

      By iain_ST44GA · Posted

      also possibly backed up to my filler and shat down it! 🤣
    • Julsmadrid
      RB25 Drama's

      By Julsmadrid · Posted

      Ok so i would love some advice here please, i purchased an R33 a few months back and its had a few mods done to the engine, its an RB25det running a Master ECU, 1200cc injectors, bigger turbo, oil cooler, oil filter relocation kit, Spool H-beam rods, acl/ross pistons. When i removed the motor from the vehicle (as its getting a respray) i thought i would compression test it and these are the following results. Cylinder 1-145psi, Cylinder 2-143psi, Cylinder 3-125psi, Cylinder 4-145psi, Cylinder 5-140psi, Cylinder 6-135psi this test was done with the motor on the ground and powering up the starter motor. I dropped the sump and found broken oil squirters on cylinder 3,5 and 6. I was told my rings are probably worn so i stripped the motor completely to get a new set of rings for it. The trouble is no one has these rings anywhere and they have to be custom made by Ross over in the states and will cost about $600+$200 delivery. My question is how can i tell if my rings are at fault and if they are still ok and is this price ok for a set of rings?
×
×
  • Create New...