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Variable Geometry Turbo Technology for the Supra?


Gaz6002
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Anyone heard of a 2JZ-GTE with VGT technology being developed?

 

I've been thinking about this for a while now and may well try it this year ready for next.

 

The technology does seem to be out there and in use on a few cars, i.e. Porsche 997 and various diesel engines.

 

Would you need a wastegate? I'm thinking not but maybe to have absolute control over the system?

 

I would think that the electronics will be the hard bit, after the turbo has been sourced of course!

 

Ideas and input are welcome :)

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Anyone heard of a 2JZ-GTE with VGT technology being developed?

 

I've been thinking about this for a while now and may well try it this year ready for next.

 

The technology does seem to be out there and in use on a few cars, i.e. Porsche 997 and various diesel engines.

 

Would you need a wastegate? I'm thinking not but maybe to have absolute control over the system?

 

I would think that the electronics will be the hard bit, after the turbo has been sourced of course!

 

Ideas and input are welcome :)

 

1.) It's on 1 Petrol engined car....and it's a £100,000 car at that.

2.) Diesel Applications don't count.

3.) No you don't need wastegates.

4.) It will happen when someone wants to stump up the R&D costs.....

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Anyone heard of a 2JZ-GTE with VGT technology being developed?

nope

I've been thinking about this for a while now and may well try it this year ready for next.

Excellent.

I take it you have looked at the stock turbos and have found alternative VGT variants, right?

The technology does seem to be out there and in use on a few cars, i.e. Porsche 997 and various diesel engines.

Yep, Porches that were designed 10+ years later than the supra mkiv and diesels that run EGTs 200+C cooler

Would you need a wastegate?

If done properly then you shouldn't need one

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1.) It's on 1 Petrol engined car....and it's a £100,000 car at that.

 

It's also on a few other non-mass produced cars though isn't it? From 1989... http://en.wikipedia.org/wiki/Variable_geometry_turbocharger

 

2.) Diesel Applications don't count.

But the technology is there and could well be utilised

 

3.) No you don't need wastegates.

I was under the impression that you would need one if the vanes didn't create the perfect running conditions at all times

 

4.) It will happen when someone wants to stump up the R&D costs.....

 

Well I'm still considering it.

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It's also on a few other non-mass produced cars though isn't it? From 1989... http://en.wikipedia.org/wiki/Variable_geometry_turbocharger

 

But the technology is there and could well be utilised

 

I was under the impression that you would need one if the vanes didn't create the perfect running conditions at all times

 

Well I'm still considering it.

 

VNT/VGT/VVT have all been tried, and until the Porsche 997T came along all had pretty much failed. Now that the Porsche has done it, IMO you'll need to wait till a few more OEM's use this technology on petrol engines before trying it aftermarket. Let the OEM's get the reliability, operating issues sorted.

 

As for the wastegate....not unless you've used the wrong turbo to start with.

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VNT/VGT/VVT have all been tried, and until the Porsche 997T came along all had pretty much failed. Now that the Porsche has done it, IMO you'll need to wait till a few more OEM's use this technology on petrol engines before trying it aftermarket. Let the OEM's get the reliability, operating issues sorted.

 

 

This does sound like good advice, but unfortunately i'm a little too impatient for this and have a tendancy to learn the hard way.

 

I'm going to do a little more research and see what I come up with. I understand your sentiment Alex and thanks for your input :)

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There was a Borg Warner distributor on here a while ago.. why not start by asking for a price for a pair of the turbos. Or are you thinking of going single with it?

 

The Garett VNT25s on eBay are *old*, like that one-off VNT petrol 1970s (?) car that there's some info on somewhere, so probably best avoided.

 

I would expect the electronics to be quite straightforward. It'll be just like controlling a wastegate, although you'd need a flexible EMU to work it.

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Diesel exhaust systems run much cooler than petrol, which is why diesel applications don't really count - the hardware has to be a lot less robust due to the lower temps. Hence it appearing on an expensive car to start with.

 

If you still need a wastegate you've failed to achieve your goal ;)

 

-Ian

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Your turbo acts like a stocker at low rpm and expands to a T61 as it spins up and as the revs increase. So mondo fast spool with no tradeoff in top end power :thumbs:

 

-Ian

 

It was a kind of rhetorical question ...but I couldn't find a smiley for that. ;)

The second question was designed to make people think - "ah, it's really not worth it given that for the cost I could buy a small island."

 

Good luck to Gaz finding a solution though - after all I bet they laughed when the first cave man made a round wheel and said "ugga ug gug uggugugaaa" to his mates.

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Garrets next Gen Performance turbo's will use their Slidevane Technology. The company is also investigating a "dry" turbo that uses air bearings borrowed from its aerospace division. Such a unit would eliminate Oil and bearing failure and allow turbos to be installed in any orientation.

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Garrets next Gen Performance turbo's will use their Slidevane Technology. The company is also investigating a "dry" turbo that uses air bearings borrowed from its aerospace division. Such a unit would eliminate Oil and bearing failure and allow turbos to be installed in any orientation.

 

Will this stuff come to fruition though? I came across the Hydracharger the other day - nothing came of that.

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On a slightly different subject, has anyone looked at using a solenoid controlled compressor bypass? I thnk these are used on some Porches. They are like a recirculating BOV but the amount of recirculation is controlled by a PWM vacuum signal, like a wastegate.

 

When on part load, you can keep your turbine spinning but offload the compressor. I don't think they could flow enough air to come fully off boost at full chat, so you would still need a wastegate, but the low-down boost control would be done on the compressor bypass duty cycle.

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On a slightly different subject, has anyone looked at using a solenoid controlled compressor bypass? I thnk these are used on some Porches. They are like a recirculating BOV but the amount of recirculation is controlled by a PWM vacuum signal, like a wastegate.

 

When on part load, you can keep your turbine spinning but offload the compressor. I don't think they could flow enough air to come fully off boost at full chat, so you would still need a wastegate, but the low-down boost control would be done on the compressor bypass duty cycle.

 

I don't understand that, it reads to me like lowering the amount of boost the engine sees despite the turbo running flat out? Why would you want to do that?!

 

-Ian

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And assuming it is exhaust powered, what keeps the turbine spinning when all that charge is bypassed and not combusted? I'm sure you'd have trouble matching the turbine/compressor to work well and still be a sensible match for normal conditions.

 

I know a few people running VATN turbo's on petrol engines pushing out around 140bhp/litre and have been doing so for some time now. I have also run a VNT Garrett unit on a petrol engine, the real trickery is mapping the control system for it to suit all conditions. Temperatures can be an issue but how much that affects you depends on the usage of the vehicle.

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I don't understand that, it reads to me like lowering the amount of boost the engine sees despite the turbo running flat out? Why would you want to do that?!

 

-Ian

 

Because as soon as you closed the solenoid, you would have instant boost. Effectively zero lag.

 

And assuming it is exhaust powered, what keeps the turbine spinning when all that charge is bypassed and not combusted? I'm sure you'd have trouble matching the turbine/compressor to work well and still be a sensible match for normal conditions.

 

You could spin the turbo up using the same technology as anti lag. Not very environmentally friendly though, and you'd probably be going through turbo's at a fair old rate, and it would certainly put you on the badside of the neighbours if you needed to run the car early in the morning. But hey, details details.... ;) :D

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I used to work on VNT diesel engine calibration for OEM's.

 

I nearly had myself a nice pair of garrett VNT's too, but forgot to pick them up when I left where I worked. DOH!

 

For the control system you'll need a speed/load based pressure demand map and a base % demand map that roughly achieves these pressures. You can then use PID control terms to fine tune the control to the pressures you require and have all kinds of modifier maps (such as ambient temp, engine temp, atmospheric pressure, turbo speed, EGT etc) to keep everything within limits. Hell, you can even have transient overboost if you like (my favourite function ;)).

 

Or you could simply control with a std turbo pressure actuator that opens the VNT vanes when the boost pressure is reached or exceeded. Not very variable, but simple!

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