Rb25/30 Neo Gt3076 Exhaust Housing Size?

[R31Nismoid]

re: dyno low reading...

Everyones dyno is "low reading" these days.

[satanic]

Interesting to see that people are still concerned with boost dropping off at high RPM when things like "RPM Offset" is widely available now... can literally force the boost the remain flat regardless of componentry (just takes a lot of patience on the dyno)

[Cubes]

RPM Offset?

Explain?

If the gate is being blown open due to back pressure behind the flapper over coming the wastegates spring there's not a lot you can do about it apart from run a larger exhaust a/r or stiffer actuator.

[tridentt150v]

re: dyno low reading...

Everyones dyno is "low reading" these days.

True, unless its the dyno you don't use = the opposition!!

BTW my 3076 had the voluted comp cover/surge slots as well, 100mm/60mm intake.

[satanic]

I'm not an expert but my Profec E01 has this function and it is very easy to use...

1) do a full run on the dyno at the desired boost settings

2) analyze graph with RPM & PSI readings

3) set E01 RPM offset range and increments (say your boost drops off between 5,000 and 7,000, you'd set the range between 4,500 and 7,250)

4) set values that increase / decrease the duty cycle of the solenoid so that you can achieve a flat boost curve

LINK: http://www.mohdparts.com/emanage/manuals/p...1_manual/21.jpg

[Shaun O]

Sounds interesting, do you have before and after plots of this?

[satanic]

Unfortunately no... but can confirm that it works wonders on my setup (Turbonetics GTK650, 60mm W/Gate, E01)

As I said though, takes a while to setup properly on the dyno - but well worth it.

[Cubes]

Ahh yep... BUT there is a point where tweaking the EBC fails to work any further.

[satanic]

At which time you know you need some different components... (e.g. stronger w/gate springs, bigger w/gate) - the EBC should be good for 99% of applications provided you are piecing together a logical system; it will fail without a doubt if you are pairing parts up that shouldn't be together.

[R31Nismoid]

EBC's are a waste of money

Even more so with a external gate

[satanic]

Uhuh... I'm sure the entire world agrees with you on that one

[Cubes]

IMO EBC's are there to simply 'tweak' the boost level close to what the actuator is rated at.

I'm attempting something a little different. I have went with a large diaphragm 14psi actuator that has a really really stiff spring. It appears to do the trick as I have been easily able to run 18psi up over 5000rpm where as previously it would tail to 16.6psi.

[satanic]

Also don't forget that an EBC allows you to completely change the way boost comes on... the difference is huge when I have the EBC OFF vs ON. Other wankier functions are also handy under the right conditions as well (e.g. overtake boost).

I highly doubt you can have a car out-perform another in terms of w/gate only vs w/gate + EBC.

[bubba]

Also don't forget that an EBC allows you to completely change the way boost comes on... the difference is huge when I have the EBC OFF vs ON.

+1 The difference is very noticable, at least in my setup.

[Spoolup]

Good EBC'c like the AVCR can keep boost consistent with the duty cycle feature - my engine holds a flat 23 psi now, where as before it would bleed boost back to 20 psi by redline.

That is a 60mm HKS External gate with a 23 psi spring

[sriver killer]

what was the end result of this?

[discopotato03]

Well as history has shown I never used my GT3076R 52T because a RWD Skylines lack of traction turned me off , I don't think they would be a real stable thing cranking out 300 kw to those two rear wheels . Anyway that's irrelevant here .

To the OP I would have used higher compression pistons something in the 9.3-9.5 area because the extra part throttle performance from reasonable static CRs is too good to throw away . Its the sort of every day torque/throttle response and if tuned properly fuel consumption that is improved here .

The other thing is that if you can get all of the above there is less need for an early boost threshold just to zip around . So straight engine power most of the time and more power from boost when you feel like having a go somewhere .

I always think about cams and static CR because the two are tied together with the actual or dynamic CR .

The way to make healthier cams work and not lose at low revs is to raise the static or measured CR . The low down trapping efficiency you lose by opening and closing the valves earlier and later you regain with the higher static CR .

As per the turbine housing I wouldn't use anything but a proper Garrett or HKS GT30 one and If you have the elevated static CR you can think seriously about using the largest 1.06 A/R one .

Bigish turbine housings are better at making boost pressure rise at a controlled rate than smaller ones , often its the wide open throttle and a turbo suddenly accelerating as the exhaust gas becomes sufficient to drive the turbine that makes the torque increase really quickly . Trying to control the situation with boost pressure often doesn't help because its the transition onto boost thats the issue here - IMO anyway .

Now a grey area exists because no ones been game to use that 1.06 A/R GT30 turbine housing I think because people think it makes the GT3582R turbos a little lazy .

I'm not sure thats really relevant because what a GT30 turbine does in a big GT30 turbine housing won't be the same as what a GT35 turbine does in a big GT30 turbine housing . I'm sure I've mentioned a number of times over the years that if you look at GT30R and GT35R turbine maps the flow rates are different for the three GT30 housing A/R sizes and the GT35 turbine "sort of" roughly equates to being one A/R size up flow wise for the same actual housing size with a GT30 turbine .

Now its your calls but I would have thought that the whole idea of having the big 3L RB30 was to make easier lazier torque than an RB25 or 26 does and not need to chase low to mid range torque that a 9.5CR 3000cc engine should have to start with .

I dunno , maybe the thing that people worry about is not getting the almighty rush when an engine suddenly leaps on to boost and feels to go like buggery .

The thing that amazes some people is watching a factory supercar like say a Porsche make the leap to light speed , I watched one do this once and it didn't look at all violent or particularly dramatic . But when the brain caught up to just how fast that car disappeared towards the horizon I could tell that it was a missile .

Out of time back later .

My thoughts only , cheers A .

Edited June 26, 2011 by discopotato03

[sriver killer]

Well as history has shown I never used my GT3076R 52T because a RWD Skylines lack of traction turned me off , I don't think they would be a real stable thing cranking out 300 kw to those two rear wheels . Anyway that's irrelevant here .

To the OP I would have used higher compression pistons something in the 9.3-9.5 area because the extra part throttle performance from reasonable static CRs is too good to throw away . Its the sort of every day torque/throttle response and if tuned properly fuel consumption that is improved here .

The other thing is that if you can get all of the above there is less need for an early boost threshold just to zip around . So straight engine power most of the time and more power from boost when you feel like having a go somewhere .

I always think about cams and static CR because the two are tied together with the actual or dynamic CR .

The way to make healthier cams work and not lose at low revs is to raise the static or measured CR . The low down trapping efficiency you lose by opening and closing the valves earlier and later you regain with the higher static CR .

As per the turbine housing I wouldn't use anything but a proper Garrett or HKS GT30 one and If you have the elevated static CR you can think seriously about using the largest 1.06 A/R one .

Bigish turbine housings are better at making boost pressure rise at a controlled rate than smaller ones , often its the wide open throttle and a turbo suddenly accelerating as the exhaust gas becomes sufficient to drive the turbine that makes the torque increase really quickly . Trying to control the situation with boost pressure often doesn't help because its the transition onto boost thats the issue here - IMO anyway .

Now a grey area exists because no ones been game to use that 1.06 A/R GT30 turbine housing I think because people think it makes the GT3582R turbos a little lazy .

I'm not sure thats really relevant because what a GT30 turbine does in a big GT30 turbine housing won't be the same as what a GT35 turbine does in a big GT30 turbine housing . I'm sure I've mentioned a number of times over the years that if you look at GT30R and GT35R turbine maps the flow rates are different for the three GT30 housing A/R sizes and the GT35 turbine "sort of" roughly equates to being one A/R size up flow wise for the same actual housing size with a GT30 turbine .

Now its your calls but I would have thought that the whole idea of having the big 3L RB30 was to make easier lazier torque than an RB25 or 26 does and not need to chase low to mid range torque that a 9.5CR 3000cc engine should have to start with .

I dunno , maybe the thing that people worry about is not getting the almighty rush when an engine suddenly leaps on to boost and feels to go like buggery .

The thing that amazes some people is watching a factory supercar like say a Porsche make the leap to light speed , I watched one do this once and it didn't look at all violent or particularly dramatic . But when the brain caught up to just how fast that car disappeared towards the horizon I could tell that it was a missile .

Out of time back later .

My thoughts only , cheers A .

Ive pmed that many people with no luck in response or information in regards to 3076r on a rb30det.

Nothing firm in the concrete that power/torque tapers off with the .82 housing.

willing to try a 1.06 housing, this should come on with a smooth linear power band.

all this with the 8.3:1 compression that the stock rb30E pistons give me

the gains to be had by going 35R .82 rear seem to be good, a easy 350rwkw with same response as a 3076r .82 on a rb25det

a hell of alot easier sticking with the turbo that I have got tho, plus I enjoy the anti surge ported front housing

[discopotato03]

I think a low CR RB30 is a big handicap but to each their own . 9.3 would be noticably better IMO .

A .

[sriver killer]

I think a low CR RB30 is a big handicap but to each their own . 9.3 would be noticably better IMO .

A .

Its $100 dollar pistons vs $1000 dollar pistons,

the boost in compression would definitely be better though i think it will run just fine