A positive-boost turbo system???

[Dirgle]

I was digging through the rumor mill today a came across the Nissan GT-R proto.

One rumor that was confirmed by Mr. Carlos Ghosn, President and CEO of Nissan Motor Co back on April 13 is that it will receive the Nissan badge here in the U.S. Market. So be ready for the Nissan GT-R in 2007.

One rumor that is unconfirmed is that it will come with a positive-boost turbo system.

"Other performance features are, supposedly, a positive-boost turbo system. This means that the GT-R will never fall into negative boost and, like a supercharger, will always have boost available. This should make power delivery very linear, but, once again, we have yet to hear official word from the PR machine at Nissan."

Now for the question. Is this even possible?!? This sounds like a really great idea, but I don't believe every thing I read. This does seem far fetched; however turbo technology has come a long way. Maybe it has become possible to achieve this; it would be a huge step forward for turbos. So once again, is this possible? And if it is where it has been used? And if it is used, does it work as well as the idea sounds?




I wasn’t sure where to post this, but if this tech does exist, I would like to debate the feasibility of using a system like this on the 7M. So I figured general would be a good starting place for it incase it does go that way. Thou, the mods can feel free to move it to OT if the thread doesn’t go in that direction.

 

[miggles]

positive boost sounds like antilag to me.

 

[IJ.]

Wonder if this means they've gotten VNT tech to work on a Petrol motor?

 

[miggles]

is that the variable vanes on a turbo as from the early F1 cars?

 

[Dirgle]

IJ: It's possible, I was wondering if that was the case myself, or if it was something else.

Miggles:http://www.honeywell.com/sites/ts/t...GMKQK64U00ACROYP858GKIH564VY0812155701757.htm
They have been using them on the new Diesel motors for a few years now. But EGTs on petrol motors prevent them from being used, so far.

May be Nissan fixed this

 

[IJ.]

Yep I know someone was playing around with a Porsche recently and got it to work!

Will be a very cool thing if it is and I guess with advanced composites it's possible now!

 

[mixmastermatt]

VATN FTW!!1!

They have had some VATN turbo's for a few years now available as bolt on upgrades. A guy a met at a autocross event had one on his miata. Very expensive, though.

 

[SupraChrisMk3]

Is this the same thing as Variable Geometry Turbo? I have heard of them being used on passenger truck diesel engines, and I know that the new 911 Turbo(997) uses them.http://www.caranddriver.com/previews/10826/2007-porsche-911-turbo-997.html I haven't heard of the VGT's eliminating lag but that they can spool a lot quicker and still make good top end power because of the variable geometry. I have just never heard anyone claim that they eliminate lag.

 

[lanternman]

The other possibility is that they are using electronically assisted turbos. I thought I read somewhere about the attempt of having electric motors spool the turbo and have the engine do the rest. (This information is at least a year and a half old, so who knows what they are up to now.)

 

[Dirgle]

SupraChrisMk3: This is what I have heard as well, and the reason I thought I would ask you guys if you had any ideas about the ace Nissan might have up its sleeve. It might just be really good tuning.

Many people have said that the Ford Falcon XR6 has no discernable lag, coming from it's standard turbo, that it runs at 6psi on it 4.0L 6cyl. It produces its peak torque at 2000RPM. Now if this can be considered the same as Nissans positive boost turbo system, possible but I doubt it. However it defiantly is the product of some very good tuning. Nissan clams that Cosworth is designing the motor, and we know Cosworth can design some wicked motors, so it really makes me curious as to what might be going on.

Lanternman: This is also possible as well, but I have heard very little information about this type of turbo assist, though I know it is in development, so I can’t say much more than that. Maybe someone else can comment further on the idea.

 

[boost fiend]

well, now i feel like a ass.

someone came throught the shop a couple of days ago and was talking about a adjustable turbo on there powerstroke f 250. i looked at him and said, "your buddy dont know shit about turbo's. the fins dont move cuz they are balanced." it has a electronicaly controled garrett turbo.

guess i just got proved wrong. back to doing hours oof research i guess.








damn, i hate being wrong like that. cant win 'em all i guess.

 

[Dirgle]

Don't feel too bad, most people don't know about these turbos yet. They only exist on a hand full of trucks and a couple of Porsches now.

Now you know, go forth and spread the word

 

[boost fiend]

and i shall. i need to do more research on this. looks intersting.

 

[Adjuster]

VATN hot sides have been around for years, but as everyone's noted, they have not been very common on passenger cars.

Areodyne (SP?) from england was selling VATN setups where they did not even need an oil supply.... You just added oil every now and then, and the turbo was completly self contained. (Said it worked better as there was no engine contaminates in the oil, and the turbo held a small tank of oil built into it. Also they used oil made for Jet engines, so it is very high temp, and very high quality.

No idea why these VATN turbo's never caught on. The price was steep, about 3k for the turbo only. (Of course, it does not need a wastegate, and with no oil or coolant fittings, your done.)

I'd like to see a VATN hot side adapted for the Garrett GT based turbo's.

Imagine a GT42 that spooled more like a GT30...? It's possible with the right design. Very high flow on the top, and very fast gas speeds down at lower RPM where you need it to spool up the turbo faster.

There will always be lag unless they use electric or fluid assited turbines. (Garrett has made hydraulic turbo's and electric spool up ones that had the motor built into the compressor housing. On the hydraulic one, there was no exhaust housing. It was replaced by a small turbine where high pressure hydraulic fluid was shot over it to spin the turbo. Very instant power, low heat and you have a nice pump already on your car... The PS system.)

Imagine this.
Since most new engines are throttle by wire, and completly computer controlled, it would be no huge deal to combine a high pressure valve system using a high pressure power steering pump and accumulator.
During normal engine operation, the turbo is off for best fuel economy.
When you need power, the computer senses the load, and your foot on the gas, and not only opens the throttle, but also spools up a turbo to 10psi or whatever in less than 1/4 second. The accumulator would hold a small amount of fluid under high pressure, say 1500lbs or more, and then release that over the vane to give you boost. The pump would be over driven, like every PS stetup, and quickly would make plenty of pressure to provide for the boost as long as you need it, or to "re-charge" the accumulator when the load was reduced.

I'm supprised it has not allready been developed.

 

[Dirgle]

Great info Adjuster, good to see a few more ideas thrown in here.

 

[Nick M]

Now for the question. Is this even possible?!?

I dont understand the question I guess. Becuase as soon as you close the throttle, your manifold goes into vaccum. Perhaps they have supercharger system of some sort, and are still using the terminology of a turbine?

A Diesel without the throttle plate is never in vaccum, and 855 CID spools even the biggest turbochargers instantly, so it is like an instant on. Not that all heavy duty powerplants use the Cummins 855.

The hydraulic turbine sounds interesting. Since hydroboost brakes work pretty well.

 

[Dirgle]

I don’t understand the question I guess. Because as soon as you close the throttle, your manifold goes into vacuum.

I was a little confused about this as well. I can only assume that they mean pre-throttle plate intake track pressures. But I though there might still be something I haven’t heard about, so I asked.

I've worked on a few Cummins (My favorite thing to do to anybody helping me is tell them to find the spark plugs. :biglaugh: ). The instant spool of some diesels is very nice. So it would be equally nice to do this to a petrol motor. Of course the system would not be able to be setup like a diesel is.

So to clarify my question.

Is there some new way to achieve positive intake track pressures, pre-throttle body, on a petrol motor when it is at or near idle, and still maintain compressor efficiency at the top end of the RPM band?

.

 

[outofstep]

The biggest problem with VNT is getting it to run on gas. Diesel runs much cooler. Gas will trash a VNT in short order.


They could be using oil pressure to keep the turbo spooled. That's been done before.

I'd like to see working VNT on gas. It makes the newer garret GT turbos look like a fucking joke.

 

[Nick M]

Is there some new way to achieve positive intake track pressures, pre-throttle body,

Before the throttle plate is called ported vaccum. But you dont have any until the plate is opened. Or very little anyway. If you have a throttle body with a plate, you have vaccum. Or more accurately, lower pressure.

 

[smokey]

i beleive some of the newer BMW's have this system installed on them