bondango Posted January 6, 2009 Share Posted January 6, 2009 I believe Ryan has been itching to have a go at a pair of VNT's. He was trying to get me to buy some off his brother and modify my install to fit them, but I just couldn't be doing with the additional headache. If they were a straight replacement that's exactly what I would have now. I'd love to see a Supe with a twin VNT kit though, would be very impressive set-up indeed. This is the way forward with twins period. for example, The Variable Turbine Geometry (VTG) tubbies for the Prosche use a Bosch controller to operate the vanes. The controllers adjust the vane angle (pitch) in relation to engine speed/exhaust flow to maintain peek boost. The controllers are fed a simple PWM signal from the Motronic ECU So Any ECU with 2 avialable programmable PWM outputs can control the porker turbbies You just need a good mapper who can put the technology to work *Cough* Dimitri Quote Link to comment Share on other sites More sharing options...
JustGav Posted January 6, 2009 Share Posted January 6, 2009 This is the way forward with twins period. for example, The Variable Turbine Geometry (VTG) tubbies for the Prosche use a Bosch controller to operate the vanes. The controllers adjust the vane angle (pitch) in relation to engine speed/exhaust flow to maintain peek boost. The controllers are fed a simple PWM signal from the Motronic ECU So Any ECU with 2 avialable programmable PWM outputs can control the porker turbbies You just need a good mapper who can put the technology to work *Cough* Dimitri Again from what I've read, it seems to operate in a reverse wastegate style... ie it is pressurized when there is less exhaust flow to angle the vanes to spin more and as the flow increases the vane pressure is released allowing them to have less angle of attack. One of the issues was supplying the pressure, but fully agree with you that a good ECU should easily be able to control it, and since the idea being with VNT is to get to boost and hold it, they shouldn't be as black magic as they been made out to be. Although I do think some of the more advanced non-WOT stuff may be tricky it shouldn't be impossible. Quote Link to comment Share on other sites More sharing options...
dandan Posted January 6, 2009 Share Posted January 6, 2009 Bondango - I read somewhere that the 997 Turbo's turbos are not true VNT in the commonly understood sense (multiple vanes) and are actually a lot closer to the SP valve type setup but with mapped conrol over the "flapper" position. Are you referring to the OEM 997 turbos in your description above? Quote Link to comment Share on other sites More sharing options...
bondango Posted January 6, 2009 Share Posted January 6, 2009 Yep 997's, its the actual adjustable vanes in the turbine housing that control the flow of exhaust gas towards the turbine. VNT (variable nossle) adjusts the throat section size to vary flow At low rpm : The vanes are partially closed, reducing the area hence accelerating the exhaust gas towards the turbine. Moreover, the exhaust flow hits the turbine blades at right angle. Both conditions make the turbine spin faster. At high rpm : At high rpm the exhaust flow is strong enough. The vanes are fully opened to take advantage of the high exhaust flow. This also release the exhaust pressure in the turbocharger, saving the need of wastegate. I think Porsche have a patent on the technology they use, is due to the materials used due to the difference in heat compared to a deisel setup. Quote Link to comment Share on other sites More sharing options...
Ryan.G Posted January 6, 2009 Share Posted January 6, 2009 This is the way forward with twins period. for example, The Variable Turbine Geometry (VTG) tubbies for the Prosche use a Bosch controller to operate the vanes. The controllers adjust the vane angle (pitch) in relation to engine speed/exhaust flow to maintain peek boost. The controllers are fed a simple PWM signal from the Motronic ECU So Any ECU with 2 avialable programmable PWM outputs can control the porker turbbies You just need a good mapper who can put the technology to work *Cough* Dimitri It will need alot more than just 2 PWM outputs.. Will also need an Ems which can: - Support dual pressure input signals, for both the turbo's - Dual closed loops control maps to ensure the turbo pressures are the same no matter what the throttle, engine loading and for when the vanes clog up, which they do! - Then i expect you will have to still fit a external wastegate as exhaust flow will be different to what the turbos are designed for, so thats another closed loop wastegate map. - Like the Porsche you will have to i expect run Closed loop Lambda control as well with the VTG turbos. To do this properly you will need an Ecu which has fail safes for this also. Only one ecu i know could do this properly IMO, Solaris Quote Link to comment Share on other sites More sharing options...
dandan Posted January 6, 2009 Share Posted January 6, 2009 Yep 997's, its the actual adjustable vanes in the turbine housing that control the flow of exhaust gas towards the turbine. VNT (variable nossle) adjusts the throat section size to vary flow http://www.autozine.org/technical_school/engine/VTG_4.jpg At low rpm : The vanes are partially closed, reducing the area hence accelerating the exhaust gas towards the turbine. Moreover, the exhaust flow hits the turbine blades at right angle. Both conditions make the turbine spin faster. At high rpm : At high rpm the exhaust flow is strong enough. The vanes are fully opened to take advantage of the high exhaust flow. This also release the exhaust pressure in the turbocharger, saving the need of wastegate. I think Porsche have a patent on the technology they use, is due to the materials used due to the difference in heat compared to a deisel setup. Have you seen the 997 ones in person and they are definitely the normal vane type setup like the image you posted? Quote Link to comment Share on other sites More sharing options...
Kranz Posted January 6, 2009 Share Posted January 6, 2009 I believe Ryan has been itching to have a go at a pair of VNT's. He was trying to get me to buy some off his brother and modify my install to fit them, but I just couldn't be doing with the additional headache. If they were a straight replacement that's exactly what I would have now. I'd love to see a Supe with a twin VNT kit though, would be very impressive set-up indeed. They were my VNTs, brand new and very very nice bits of kit for about 1/10th of the price they should have cost! I was going to fit them to my Supe, but sadly plans changed and it all had to go You still not got round to using them Ryan??? Quote Link to comment Share on other sites More sharing options...
Ryan.G Posted January 6, 2009 Share Posted January 6, 2009 They were my VNTs, brand new and very very nice bits of kit for about 1/10th of the price they should have cost! I was going to fit them to my Supe, but sadly plans changed and it all had to go You still not got round to using them Ryan??? I ended up giving them to friend who will be using them for something abit more special in the future Quote Link to comment Share on other sites More sharing options...
bondango Posted January 7, 2009 Share Posted January 7, 2009 It will need alot more than just 2 PWM outputs.. Will also need an Ems which can: - Support dual pressure input signals, for both the turbo's - Dual closed loops control maps to ensure the turbo pressures are the same no matter what the throttle, engine loading and for when the vanes clog up, which they do! - Then i expect you will have to still fit a external wastegate as exhaust flow will be different to what the turbos are designed for, so thats another closed loop wastegate map. - Like the Porsche you will have to i expect run Closed loop Lambda control as well with the VTG turbos. To do this properly you will need an Ecu which has fail safes for this also. Only one ecu i know could do this properly IMO, Solaris Ryan rome wasnt built in a day. One step at a time lad lol forget about controlling both turbos indvidually for now though. make it easy, and control them as a pair i.e. signal control, both turbos operate the same. Vanes should not clog, remember the materials and design for these have been developed for petrol engines and its part of the porsche patent on them. The first thing would be to control them in a simple manner i.e. rpm/engine load control map, and take it from there. as said, this would take a lot of time, trial and error, but such technology for the aftermarket performance market shouldnt be a million miles away Quote Link to comment Share on other sites More sharing options...
bondango Posted January 7, 2009 Share Posted January 7, 2009 Have you seen the 997 ones in person and they are definitely the normal vane type setup like the image you posted? Dan not in person, but when i last chatted to dimitri about the porkers he had aquired i remember him saying they were not the nossle type and how the vanes were controlled. which seems to tie in with the internet info on the porsche vgt setup Quote Link to comment Share on other sites More sharing options...
bondango Posted January 7, 2009 Share Posted January 7, 2009 Dan heres the link to the Borgwarner VGT description :- http://paultan.org/archives/2006/08/16/how-does-variable-turbine-geometry-work/ And heres a link about the new Borg-Warner Sequential VGT system that they have started putting into production vehicles http://paultan.org/archives/2007/12/14/borgwarner-r2s-sequential-vgt-turbocharger/ Quote Link to comment Share on other sites More sharing options...
Ryan.G Posted January 7, 2009 Share Posted January 7, 2009 Ryan rome wasnt built in a day. One step at a time lad lol forget about controlling both turbos indvidually for now though. make it easy, and control them as a pair i.e. signal control, both turbos operate the same. Vanes should not clog, remember the materials and design for these have been developed for petrol engines and its part of the porsche patent on them. The first thing would be to control them in a simple manner i.e. rpm/engine load control map, and take it from there. as said, this would take a lot of time, trial and error, but such technology for the aftermarket performance market shouldnt be a million miles away This thread is about sequentials though The tech in the aftermarket performance market is definatly available already now just its alot of money to buy the VTG turbos and then make everything up. If someone does it though i will map it and set it up for free Ryan Quote Link to comment Share on other sites More sharing options...
Kranz Posted January 7, 2009 Share Posted January 7, 2009 I ended up giving them to friend who will be using them for something abit more special in the future Good luck to them Let us know how they get on? Quote Link to comment Share on other sites More sharing options...
bondango Posted January 7, 2009 Share Posted January 7, 2009 This thread is about sequentials though Ryan they will spool that quick we can lie and say they are working sequentially just put a lil ignition reatard mid flight and say its the pause before second coming online Last set i seen on ebay germany were over 3K so im out Quote Link to comment Share on other sites More sharing options...
Kranz Posted January 7, 2009 Share Posted January 7, 2009 You don't need the VNTs to work sequentially..... the fact that they can probably produce masses of boost at 1000 rpm in parallel mode would remove any requirement for sequential operation. Also the boost delivery would be a seamless x psi if required all the way up the rev range Quote Link to comment Share on other sites More sharing options...
Gazboy Posted January 7, 2009 Share Posted January 7, 2009 Surely the whole point of variable tech is to ditch the sequential operation altogether? Quote Link to comment Share on other sites More sharing options...
bondango Posted January 7, 2009 Share Posted January 7, 2009 thats was my point. But, it really depends on how well you can control the technology, and how well it can be implemented outside the manufacturer market as porsche and BW spent a lot of time in R&D in the delevopment of VGT's specifically for the 993 in conjunction with the other technologies they used in the engine. where i see the Sequential operation coming into play, is a system designed for Big HP applications, i.e. small VGT turbo for low to medium boost and a larger VGT turbo for medium to high boost. Quote Link to comment Share on other sites More sharing options...
Gazboy Posted January 7, 2009 Share Posted January 7, 2009 (edited) Christ that aussie could barely get that GT28 & T78 (or whatever they were) compounder set up working spot on and they spent years on that project (they were clever feckers too). Edit, here's a diagram of their set up: http://mesmerize.nokternl.com/img/SSCOSTT.jpg Edited January 7, 2009 by Gazboy (see edit history) Quote Link to comment Share on other sites More sharing options...
Gazboy Posted January 7, 2009 Share Posted January 7, 2009 Their turbos were a GT2560 with an A/R of 0.64 and a GT3582R 1.06 A/R. I currently cannot find any working dynocharts. Btw they've been working on this since mid 2003! Quote Link to comment Share on other sites More sharing options...
bondango Posted January 7, 2009 Share Posted January 7, 2009 yeah gaz, it was a complicated and maybe over engineered setup imho. but at least technology has moved on so we can control the turbo's themselves with out the need of complicated vac and exhaust routing, a multitude of VSV's valves and Flaps Problem is, how anal do you have to be about Supra's to put so much time, effort, research, and money something like this? also, Is the performance sector still strong enough for blitz/hks/apexi to develop the technology? If not, its left down to enthusiasts to do it. The technology is there, But as ryan says, it may be a long time before it comes within budget for us mere mortals. Quote Link to comment Share on other sites More sharing options...
legendswraith Posted January 7, 2009 Share Posted January 7, 2009 I did do a big reply to this when i was at work, but the system went down. In respects to the VGT although it would be beneficial to have 2 VGT turbos there is no reason that the benefits of just having the larger turbo with VIGVs wouldn't give you near as the same performance depending on how much the difference was between the 2 turbos. If anyone is actually interested in the vigvs on a vgt turbo i can get the controller method (or similar) and post it. Same principle has been used for donkeys on axial flow gas turbines Quote Link to comment Share on other sites More sharing options...
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