Garrett Medium Frame Gtx Turbos

[ShiftyTys]

thats what I was getting at, a lot of people have been saying they will spool the same as the next size down and make more power.

Imo the GT comp wheels are fine as they are/were, its the turbine that needs work

Ok so now what do I buy???

[Lithium]

For what its worth I have a Garrett GT3076R with a .82a/r internally gated turbine housing, I bought it back when there was much hate on Garrett GT3076Rs... despite that most people were using some crappy T04S type version. Since then they have become a much loved combination now that its been made clear that the "REAL" GT3076R is actually worth having.

I like to think I have a bit of an idea of whats going to be worth while and what isn't, and I am on the verge of pulling the trigger on going to a twin scroll T4 exhaust manifold, built RB25 and a T4 .92a/r internally gated version of this turbo:

http://www.full-race.com/store/turbos/borgwarner-efr/borgwarner-efr-7670-turbo.html

I confident of better spool than what I have with the GT3076R (probably at least rivalling the GT3071R boys), and the ability to make more power.

[Rolls]

What do people think of using a quick spool valve on twin scroll turbos? seem to have some very promising results over in the states.

essentially it just blocks one of the scrolls off and slowly opens it as boost comes on, kind of like a ghetto variable vayne.

[islade]

What do people think of using a quick spool valve on twin scroll turbos? seem to have some very promising results over in the states.

essentially it just blocks one of the scrolls off and slowly opens it as boost comes on, kind of like a ghetto variable vayne.

That would only work if you had a single scroll manifold with a twinscroll turbine housing, right?

[Lithium]

What do people think of using a quick spool valve on twin scroll turbos? seem to have some very promising results over in the states.

essentially it just blocks one of the scrolls off and slowly opens it as boost comes on, kind of like a ghetto variable vayne.

I'm dubious of a single entry manifold shoving gases into a twin scroll turbo - they do show good spool results for the size turbo but most results I've seen to date don't seem to show turbos making the full power level they are capable of. I'm also not sure how durable the mechanism will be in the long run. I'm not saying they don't work, but I've not been sold on them yet.

A compound turbo type setup with wastegates phasing the flow to ensure .... that could be fun, if you had the money and ability

[badhairdave]

What do people think of using a quick spool valve on twin scroll turbos? seem to have some very promising results over in the states.

essentially it just blocks one of the scrolls off and slowly opens it as boost comes on, kind of like a ghetto variable vayne.

ghetto,

defeats the purpose of twin scroll entirely.

It isn't new tech, mazda had it on the s4 rx7 back in 86, ditched it for the s5. I'm sure others have had it longer.

Lithium, good choice. 7670 is probably the pick for an rb25, though i'm fairly interested to see how a 7064 would go.

[Lithium]

Lithium, good choice. 7670 is probably the pick for an rb25, though i'm fairly interested to see how a 7064 would go.

Cheers, I personally think for a street RB25 it could be unbeatable - could redefine what a good street setup is. Not having to buy a BOV (I run a stock one atm), or wastegates, potentially having full boost by 3500rpm and making >300kw on pump gas and having a psychopath E85 tune capable of over 400kw.

Want.

Its probably worth noting that an EFR7670 doesn't really school a GT3076R (on paper) until 20psi+

[ShiftyTys]

For what its worth I have a Garrett GT3076R with a .82a/r internally gated turbine housing, I bought it back when there was much hate on Garrett GT3076Rs... despite that most people were using some crappy T04S type version. Since then they have become a much loved combination now that its been made clear that the "REAL" GT3076R is actually worth having.

I like to think I have a bit of an idea of whats going to be worth while and what isn't, and I am on the verge of pulling the trigger on going to a twin scroll T4 exhaust manifold, built RB25 and a T4 .92a/r internally gated version of this turbo:

http://www.full-race.com/store/turbos/borgwarner-efr/borgwarner-efr-7670-turbo.html

I confident of better spool than what I have with the GT3076R (probably at least rivalling the GT3071R boys), and the ability to make more power.

So how does gtx3071.82 sound. Or .73. Forget money.

[zebra]

Cheers, I personally think for a street RB25 it could be unbeatable - could redefine what a good street setup is. Not having to buy a BOV (I run a stock one atm), or wastegates, potentially having full boost by 3500rpm and making >300kw on pump gas and having a psychopath E85 tune capable of over 400kw.

Want.

Its probably worth noting that an EFR7670 doesn't really school a GT3076R (on paper) until 20psi+

Are they the new internal gate ones?

I remember a thread about them not that long ago.

[Trozzle]

Internal gate and integrated BOV

[zebra]

ooohh I remember them now, they have the funny old school wastegate flap thing that I wasnt a fan of.

[zebra]

Wait....Found a good pic of them, looks like a half decent setup

Sorry about the thread jack btw lol

[Rolls]

That would only work if you had a single scroll manifold with a twinscroll turbine housing, right?

Yes that is exactly how they set it up.

ghetto,

defeats the purpose of twin scroll entirely.

no shit but it might bring other benefits that make it worth while, it would have more of a restriction and limit the overall power made however if it makes it spool faster than a turbo that makes equivalent peak power levels surely that is something worth investigating?

[zebra]

Why not just go a propper twinscroll setup?

[Legionnaire]

Why not just go a propper twinscroll setup?

Because with a "proper twinscroll" setup you stil have fixed housing A/R so you're optimising inherently ill concept and with quickspool valve you're one step closer to VGT? Kinda similar to buying adj. cam gears when you can actually have VVT. The latest engine I'm aware of that utilises quickspool concept is honda KA23A1 found in Acura RDX. What you actually want is to have continuously controllable turbine inlet pressure, i.e. have a VGT mechanism.

GTX compressors are good. Too bad garrett didn't bother upgrading their turbines at the same time. I'd like to see a hybrid of BW TiAl turbine and Garrett compressor though, BW compressors produce desired flow figures at much too high pressure ratios to my liking, kinda reverse situation to Garrett - ultra-modern turbine with diesel-age compressor philosophy.

GT/GTX 76mm compressor mated to 70mm EFR turbine must be good.

As for spool, I still thing GTX3071 should spool slightly faster than GT3076. GTX3076 is a real comp/turb flow mismatch, it's not like 3582, more like 3082 - high TIP pressures and narrow powerband unless conservative cams are used.

[zebra]

Because with a "proper twinscroll" setup you stil have fixed housing A/R so you're optimising inherently ill concept and with quickspool valve you're one step closer to VGT?

I would rather that than a massive amount of turbulence pre turbo, and dubious longivity of the setup

[Fat_Tony]

Because with a "proper twinscroll" setup you stil have fixed housing A/R/quote]

I don't see how a quick spool valve changes the A/R of the turbine housing. Its just a smaller entry into the same volume.

[Legionnaire]

I would rather that than a massive amount of turbulence pre turbo, and dubious longivity of the setup

Also true, but don't you think you're trying to compare bad realization of a good concept to a good realization of worse concept? In this case it favours the latter. With a well-engineered setup there is no masive turbulence pre turbo. If I can find them, I'll post some pics of a honda setup, there is no source of turbulence there.

But speaking of petrol burners we're still stuck with fixed geometry turbos for now, so we should better optimize what we have. But if i was one of the E85 users with their lower EGTs and sootless exhaust, I'd seriuosly consider some of VGT turbos currently available for CI engines.

Update: found a pic of honda VFT setup.

I don't see how a quick spool valve changes the A/R of the turbine housing. Its just a smaller entry into the same volume.

If by smaller you mean smaller area, that's exactly what "A" part of A/R stands for.

But speaking of "quick spool" valve as in "blocking one scroll of twinscroll housing at the flange" valve I do agree it is dodgy as and wouldn't use it on my car

Edited February 16, 2011 by Legionnaire

[Trozzle]

Because with a "proper twinscroll" setup you stil have fixed housing A/R

I don't see how a quick spool valve changes the A/R of the turbine housing. Its just a smaller entry into the same volume.

because with the quickspool valve, ALL the exhaust gasses will be pushed into ONE SIDE of the divided housing. The effective A/R of this single side in the housing is much smaller. Then when the valve opens, the gasses pass down both sides of the divided housing, effectively varying the A/R of the housing.

[Fat_Tony]

because with the quickspool valve, ALL the exhaust gasses will be pushed into ONE SIDE of the divided housing. The effective A/R of this single side in the housing is much smaller. Then when the valve opens, the gasses pass down both sides of the divided housing, effectively varying the A/R of the housing.

DOes a twin scroll turbo work to 100% effiency if only one side of the divided housing has exhaust flow?

Doesn't sound right to me. Hey I could be wrong.