what turbos should be in an STI Bugeye ?
09 October 2010, 12:55 PM
#31
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The intake temp was shown at about 43deg and a correction value of 3% was mentioned so I deduct what 10bhp from that 382bhp figure, looking at the boost graph it ran 382.8 @ just over 1.4 bar and it will happily run to 1.5 bar and as a 4% increase in boost duty increased the power output from 370 to 380 I am certain at 1.5 Bar the car will easily run 380+ so I feel it is a fair and accurate figure of what the car/turbo is capable of.
Cheers Iain
09 October 2010, 01:20 PM
#32
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Hi Harvey, to be honest the mapping side of the cars and the dyno stuff I know nothing about I just set the car up and Bob maps it for me, I just spoke to Bob a moment ago and he suggested that you ask him directly as he knows the car and has the graphs etc and can tell you way more about the performance side of things than I can.
Cheers Iain
Cheers Iain
09 October 2010, 01:51 PM
#33
I will do that Iain but this is getting a bit silly. I do not want to detract from what is clearly an excellent result and you have done very well to do this but the VF35 cannot make 382 bhp at 1.4 bar because it cannot flow enough air. If Pat Herborn is about I guess he will come up with a mathematical formula to prove that. 
That does not mean that you have not done exceptionally well and your result is excellent. I am not a rolling road operator but by rule of thumb I would say the figures are skewed by 4% or thereabouts, perhaps only 3.5% but it is of that order. That means you are still extracting 360-370 bhp from a VF35 turbo and that is still at the top of the tree.
You can verify all this for yourself, today, tomorrow or Monday by running your car on another Dyno Dynamics rolling road if you want to gather information to put the matter to rest or indeed the same one and log or observe air charge temperatures during the run, ambient temperature and inlet temperature. All very important to the final power figure. For instance on a run I did 23-09-2010 in front of me now, air charge temperature was 18, inlet temperature influenced by heat from the engine bay was 19 but air charge temperature rose to around 36. Now as I said I am not a rolling road operator but I would guess Len could tell you (or any other Dyno Dynamics rolling road operator) the skew achieved with a 25 degree or whatever difference between ambient and inlet temperatures.
Now as regards porting the wastegate on a VF35 (and VF34) this is something we do on a regular basis and we also do other porting work on turbos to get the results we achieve. However, porting the wastegate will not increase maximum power per se unless you are running more boost. Many of the VF35 and 34 equipped cars mapped here by Bob Rawle have had ported wastegates and sometimes other porting and it is not significant enough a modification to highlight. Indeed, almost all the turbos we supply and fit have ported exhaust inlet and if necessary ported wastegate.(and all the new turbos have uprated actuators in addition to exhaust inlet porting) It is therefore unfortunate that you attribute claims of high power from WG porting on the other
Bob has come across. WG porting is not some piece of magic as the inexperienced may be lead to believe. He has done numerous. While porting the wastegate on a VF34, 35 and TD05 20G is desireable and sometimes necessry, I have never found the need to port the wastegate on a 16G or TD04 etc.
The VF35 is prone to boost creep. ie. under full load the exhaust gasses cannot escape quick enough through the combined exhaust turbine wheel and wastegate. This causes a pressure build up and overspeed of the turbo as boost creeps. Radiusing or opening up the wastegate to close to the penny valve diameter eliminates this problem as more gas can escape but this gas is wasted because it is not driving the turbine and does not lead to additional power. This helps map the boost and keep it under control. Improving the performance of the turbo in terms of power output can be achieved by porting in other areas.
I remember when I had 367 bhp from a VF28 many years ago in my early days of Subaru involvement. Nobody believed me but I was convinced I had 367 bhp or whatever the figure was and I had the paperwork to prove it. A turbo change to an Ion Turbo in the same engine went to 417 bhp measured on several rolling roads and the same engine went on to produce 535 bhp on Optimax plus NF and 585 bhp on 102 Ron Race Fuel. Now there were loads of sceptics and doubters at the time but these were the results that I had, however, with hindsight the actual figures could be argued about much as I am pointing out to you but the truth was and what nobody can detract from was that these results, that engine and turbo, all mapped by Bob Rawle were at the very top of the tree as far as Subaru performance and development was concerned at that time and even during the early development, good enough to win Scooby Shootout by a large margin.
If you find the time to get a set of unskewed results you can actually do further work on your turbo and measure the improvements you will probably make on top of what is already clearly an excellent result which relies not only on the turbo but your existing spec.
That does not mean that you have not done exceptionally well and your result is excellent. I am not a rolling road operator but by rule of thumb I would say the figures are skewed by 4% or thereabouts, perhaps only 3.5% but it is of that order. That means you are still extracting 360-370 bhp from a VF35 turbo and that is still at the top of the tree.You can verify all this for yourself, today, tomorrow or Monday by running your car on another Dyno Dynamics rolling road if you want to gather information to put the matter to rest or indeed the same one and log or observe air charge temperatures during the run, ambient temperature and inlet temperature. All very important to the final power figure. For instance on a run I did 23-09-2010 in front of me now, air charge temperature was 18, inlet temperature influenced by heat from the engine bay was 19 but air charge temperature rose to around 36. Now as I said I am not a rolling road operator but I would guess Len could tell you (or any other Dyno Dynamics rolling road operator) the skew achieved with a 25 degree or whatever difference between ambient and inlet temperatures.
Now as regards porting the wastegate on a VF35 (and VF34) this is something we do on a regular basis and we also do other porting work on turbos to get the results we achieve. However, porting the wastegate will not increase maximum power per se unless you are running more boost. Many of the VF35 and 34 equipped cars mapped here by Bob Rawle have had ported wastegates and sometimes other porting and it is not significant enough a modification to highlight. Indeed, almost all the turbos we supply and fit have ported exhaust inlet and if necessary ported wastegate.(and all the new turbos have uprated actuators in addition to exhaust inlet porting) It is therefore unfortunate that you attribute claims of high power from WG porting on the other
two WG ported VF35s
The VF35 is prone to boost creep. ie. under full load the exhaust gasses cannot escape quick enough through the combined exhaust turbine wheel and wastegate. This causes a pressure build up and overspeed of the turbo as boost creeps. Radiusing or opening up the wastegate to close to the penny valve diameter eliminates this problem as more gas can escape but this gas is wasted because it is not driving the turbine and does not lead to additional power. This helps map the boost and keep it under control. Improving the performance of the turbo in terms of power output can be achieved by porting in other areas.
I remember when I had 367 bhp from a VF28 many years ago in my early days of Subaru involvement. Nobody believed me but I was convinced I had 367 bhp or whatever the figure was and I had the paperwork to prove it. A turbo change to an Ion Turbo in the same engine went to 417 bhp measured on several rolling roads and the same engine went on to produce 535 bhp on Optimax plus NF and 585 bhp on 102 Ron Race Fuel. Now there were loads of sceptics and doubters at the time but these were the results that I had, however, with hindsight the actual figures could be argued about much as I am pointing out to you but the truth was and what nobody can detract from was that these results, that engine and turbo, all mapped by Bob Rawle were at the very top of the tree as far as Subaru performance and development was concerned at that time and even during the early development, good enough to win Scooby Shootout by a large margin.
If you find the time to get a set of unskewed results you can actually do further work on your turbo and measure the improvements you will probably make on top of what is already clearly an excellent result which relies not only on the turbo but your existing spec.
Last edited by harvey; 09 October 2010 at 02:49 PM.
09 October 2010, 02:12 PM
#34
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I will do that Iain but this is getting a bit silly. I do not want to detract from what is clearly an excellent result and you have done very well to do this but the VF35 cannot make 382 bhp at 1.4 bar because it cannot flow enough air. If Pat Herborn is about I guess he will come up with a mathematical formula to prove that. That does not mean that you have not done exceptionally well and your result is excellent. I am not a rolling road operator but by rule of thumb I would say the figures are skewed by 4% or thereabouts, perhaps only 3.5% but it is of that order. That means you are still extracting 360-370 bhp from a VF35 turbo and that is still at the top of the tree.
You can verify all this for yourself, today, tomorrow or Monday by running your car on another Dyno Dynamics rolling road if you want to gather information to put the matter to rest or indeed the same one and log or observe air charge temperatures during the run, ambient temperature and inlet temperature. All very important to the final power figure. For instance on a run I did 23-09-2010 in front of me now, air charge temperature was 18, inlet temperature influenced by heat from the engine bay was 19 but air charge temperature rose to around 36. Now as I said I am not a rolling road operator but I would guess Len could tell you (or any other Dyno Dynamics rolling road operator) the skew achieved with a 25 degree or whatever difference between ambient and inlet temperatures.
Now as regards porting the wastegate on a VF35 (and VF34) this is something we do on a regular basis and we also do other porting work on turbos to get the results we achieve. However, porting the wastegate will not increase maximum power per se unless you are running more boost. Many of the VF35 and 34 equipped cars mapped here by Bob Rawle have had ported wastegates and sometimes other porting and it is not significant enough a modification to highlight. Indeed, almost all the turbos we supply and fit have ported exhaust inlet and if necessary ported wastegate. It is therefore unfortunate that you attribute claims of high power from WG porting on the other Bob has come across. WG porting is not some piece of magic as the inexperienced may be lead to believe. He has done numerous. While porting the wastegate on a VF34, 35 and TD05 20G is desireable and sometimes necessry, I have never found the need to port the wastegate on a 16G or TD04 etc.
The VF35 is prone to boost creep. ie. under full load the exhaust gasses cannot escape quick enough through the combined exhaust turbine wheel and wastegate. This causes a pressure build up and overspeed of the turbo as boost creeps. Radiusing or opening up the wastegate to close to the penny valve diameter eliminates this problem as more gas can escape but this gas is wasted because it is not driving the turbine and does not lead to additional power. This helps map the boost and keep it under control. Improving the performance of the turbo in terms of power output can be achieved by porting in other areas.
I remember when I had 367 bhp from a VF28 many years ago in my early days of Subaru involvement. Nobody believed me but I was convinced I had 367 bhp or whatever the figure was and I had the paperwork to prove it. A turbo change to an Ion Turbo in the same engine went to 417 bhp measured on several rolling roads and the same engine went on to produce 535 bhp on Optimax plus NF and 585 bhp on 102 Ron Race Fuel. Now there were loads of sceptics and doubters at the time but these were the results that I had, however, with hindsight the actual figures could be argued about much as I am pointing out to you but the truth was and what nobody can detract from was that these results, that engine and turbo, all mapped by Bob Rawle were at the very top of the tree as far as Subaru performance and development was concerned at that time and even during the early development, good enough to win Scooby Shootout by a large margin.
If you find the time to get a set of unskewed results you can actually do further work on your turbo and measure the improvements you will probably make on top of what is already clearly an excellent result which relies not only on the turbo but your existing spec.
That does not mean that you have not done exceptionally well and your result is excellent. I am not a rolling road operator but by rule of thumb I would say the figures are skewed by 4% or thereabouts, perhaps only 3.5% but it is of that order. That means you are still extracting 360-370 bhp from a VF35 turbo and that is still at the top of the tree.You can verify all this for yourself, today, tomorrow or Monday by running your car on another Dyno Dynamics rolling road if you want to gather information to put the matter to rest or indeed the same one and log or observe air charge temperatures during the run, ambient temperature and inlet temperature. All very important to the final power figure. For instance on a run I did 23-09-2010 in front of me now, air charge temperature was 18, inlet temperature influenced by heat from the engine bay was 19 but air charge temperature rose to around 36. Now as I said I am not a rolling road operator but I would guess Len could tell you (or any other Dyno Dynamics rolling road operator) the skew achieved with a 25 degree or whatever difference between ambient and inlet temperatures.
Now as regards porting the wastegate on a VF35 (and VF34) this is something we do on a regular basis and we also do other porting work on turbos to get the results we achieve. However, porting the wastegate will not increase maximum power per se unless you are running more boost. Many of the VF35 and 34 equipped cars mapped here by Bob Rawle have had ported wastegates and sometimes other porting and it is not significant enough a modification to highlight. Indeed, almost all the turbos we supply and fit have ported exhaust inlet and if necessary ported wastegate. It is therefore unfortunate that you attribute claims of high power from WG porting on the other Bob has come across. WG porting is not some piece of magic as the inexperienced may be lead to believe. He has done numerous. While porting the wastegate on a VF34, 35 and TD05 20G is desireable and sometimes necessry, I have never found the need to port the wastegate on a 16G or TD04 etc.
The VF35 is prone to boost creep. ie. under full load the exhaust gasses cannot escape quick enough through the combined exhaust turbine wheel and wastegate. This causes a pressure build up and overspeed of the turbo as boost creeps. Radiusing or opening up the wastegate to close to the penny valve diameter eliminates this problem as more gas can escape but this gas is wasted because it is not driving the turbine and does not lead to additional power. This helps map the boost and keep it under control. Improving the performance of the turbo in terms of power output can be achieved by porting in other areas.
I remember when I had 367 bhp from a VF28 many years ago in my early days of Subaru involvement. Nobody believed me but I was convinced I had 367 bhp or whatever the figure was and I had the paperwork to prove it. A turbo change to an Ion Turbo in the same engine went to 417 bhp measured on several rolling roads and the same engine went on to produce 535 bhp on Optimax plus NF and 585 bhp on 102 Ron Race Fuel. Now there were loads of sceptics and doubters at the time but these were the results that I had, however, with hindsight the actual figures could be argued about much as I am pointing out to you but the truth was and what nobody can detract from was that these results, that engine and turbo, all mapped by Bob Rawle were at the very top of the tree as far as Subaru performance and development was concerned at that time and even during the early development, good enough to win Scooby Shootout by a large margin.
If you find the time to get a set of unskewed results you can actually do further work on your turbo and measure the improvements you will probably make on top of what is already clearly an excellent result which relies not only on the turbo but your existing spec.
I dont really have the huge experience of yourself to go on Harvey, but something I have done here works and its not a one off and it is related to the turbo setup, ok the other supporting mods do help but what use are they if the turbo cant perform, and perform it does.
I would be happy either way to be honest, one way I do actually have a 380bhp VF35, or the other way I only have a 360bhp VF35 that runs 11 sec 1/4 miles both are pretty special in my eyes
I am sure Bob can explain way better than I can.
Cheers Iain
09 October 2010, 03:37 PM
#35
Even Bob cannot explain how a VF35 makes 382 bhp at 1.4 bar on road fuel with a bit of WG porting and uprated actuator, both of which do not add appreciably to ultimate power ie 382 bhp.
I am trying to hep you but you need to improve your understanding of how a turbo works and start with credible figures. AT in the teens and IT 40 odd is not a credible starting point.
If you take the trouble to read post 33 again you will see that porting the VF35 WG is common practice and Bob Rawle has mapped numerous of thes in the past.
None of this detracts from the fact that you have achieved fantastic results and 11.8? sec quarter on a VF35 at 1.4 or 1.5 bar on road fuel is a astounding.
I am trying to hep you but you need to improve your understanding of how a turbo works and start with credible figures. AT in the teens and IT 40 odd is not a credible starting point.
If you take the trouble to read post 33 again you will see that porting the VF35 WG is common practice and Bob Rawle has mapped numerous of thes in the past.
None of this detracts from the fact that you have achieved fantastic results and 11.8? sec quarter on a VF35 at 1.4 or 1.5 bar on road fuel is a astounding.
09 October 2010, 03:50 PM
#37
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Even Bob cannot explain how a VF35 makes 382 bhp at 1.4 bar on road fuel with a bit of WG porting and uprated actuator, both of which do not add appreciably to ultimate power ie 382 bhp.
I am trying to hep you but you need to improve your understanding of how a turbo works and start with credible figures. AT in the teens and IT 40 odd is not a credible starting point.
If you take the trouble to read post 33 again you will see that porting the VF35 WG is common practice and Bob Rawle has mapped numerous of thes in the past.
None of this detracts from the fact that you have achieved fantastic results and 11.8? sec quarter on a VF35 at 1.4 or 1.5 bar on road fuel is a astounding.
I am trying to hep you but you need to improve your understanding of how a turbo works and start with credible figures. AT in the teens and IT 40 odd is not a credible starting point.
If you take the trouble to read post 33 again you will see that porting the VF35 WG is common practice and Bob Rawle has mapped numerous of thes in the past.
None of this detracts from the fact that you have achieved fantastic results and 11.8? sec quarter on a VF35 at 1.4 or 1.5 bar on road fuel is a astounding.
Thats 30-40bhp more than I think he was expecting to see on his road dyno.3 out of 3 positive results was enough really for me to believe it was not fluke and that I was on to something but you are or at least seem 100% that its not the turbo, so what is it then?
Cheers Iain
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