I want 400bhp and a good torque figure, but.... i want it to last
18 September 2003, 05:06 PM
#34
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I made the mistake of changing more than one thing at a time 
so my boost control is now all over the place. Initial results look similar at 3300rpm but more boost capability from 4000rpm, also a LOUD jet engine type whistle when it comes on high boost which is a bit weird 
so my boost control is now all over the place. Initial results look similar at 3300rpm but more boost capability from 4000rpm, also a LOUD jet engine type whistle when it comes on high boost which is a bit weird
18 September 2003, 05:12 PM
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LMAO!! jet engine noise anit so bad
Can you explain how it is supposed to work?? does it restrict airflow lower down or something??
Rob
Can you explain how it is supposed to work?? does it restrict airflow lower down or something??
Rob
18 September 2003, 05:29 PM
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The ported shroud makes the compressor 1st stage (longer blades) flow more air at low speeds, this recirculates out via the shroud and makes the turbo 'think' its flowing more than it is and hence reduces surge at low air flows.
As air speed and flow increase, the restriction becomes the inducer diameter, the 2nd stage starts pulling a partial vacuum on the inducer section, the ported section then reverses its flow and flows air into the low pressure intermediate section just prior to the 2nd stage blades.
This effectively allows the turbo to have a larger area intake but without the inertia losses (lag/spool) normally associated with a larger compressor wheel.
Sort of like having your cake and eating it
Andy
As air speed and flow increase, the restriction becomes the inducer diameter, the 2nd stage starts pulling a partial vacuum on the inducer section, the ported section then reverses its flow and flows air into the low pressure intermediate section just prior to the 2nd stage blades.
This effectively allows the turbo to have a larger area intake but without the inertia losses (lag/spool) normally associated with a larger compressor wheel.
Sort of like having your cake and eating it
Andy
18 September 2003, 06:04 PM
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Both flow and control. A TD05 exhaust housing will flow for around 450 bhp, which is fine as that's all that is required.
Bigger turbo's need to flow more exhaust, so rather than have a HUGE big casting with integral wastegate, an external one is used. This can also have the benefit of allowing a smoother route for the gas flow to and from the turbine.
The poppet valve design of an external WG is also more progressive than a hinged flapper.
Andy
Bigger turbo's need to flow more exhaust, so rather than have a HUGE big casting with integral wastegate, an external one is used. This can also have the benefit of allowing a smoother route for the gas flow to and from the turbine.
The poppet valve design of an external WG is also more progressive than a hinged flapper.
Andy
18 September 2003, 06:54 PM
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The poppet valve design of an external WG is also more progressive than a hinged flapper.
Would it be worth running an external wastegate on the 06 with the flapper welded closed, primitive perhaps but...
Rob
18 September 2003, 07:05 PM
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I don't think it would change spool up. With the external WG the amount of gas it passes is going to be proportional to the signal from the ECU, with an internal it is non linear as the valve tends to be undersized ie the further it opens, the less change in flow.
18 September 2003, 08:31 PM
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So.....
Price wise i think the Haltech is going to be my ECU, may be determined by person mapping car...
Headers are sorted, std turbo position ATM so full GT is not an option.
Rods and pistons will most likely come from Mark, still unsure wether to keep the std STI pistons???
Bearings
Oil pump
headwork whilst engine is apart, if they cant be done by the person i want to do them i will need some pointers..
Cam profiles.. Stick with the STI cams? think so...
Turbo... Most likely another TD05/06, however i will take some moer advice when the time comes on the Garrett/Vf Option.
Now, reading back it may seem like some of this may be overkill.. but knowing me i will want more power some day.
I have loads more time with this car compared to the WRX i had.... which will help me financially and hopefully give me more time to research properly.
Anyone want to add anything else??
FMIC or Chargecooler..... Hmmmm
Rob
Price wise i think the Haltech is going to be my ECU, may be determined by person mapping car...
Headers are sorted, std turbo position ATM so full GT is not an option.
Rods and pistons will most likely come from Mark, still unsure wether to keep the std STI pistons???
Bearings
Oil pump
headwork whilst engine is apart, if they cant be done by the person i want to do them i will need some pointers..
Cam profiles.. Stick with the STI cams? think so...
Turbo... Most likely another TD05/06, however i will take some moer advice when the time comes on the Garrett/Vf Option.
Now, reading back it may seem like some of this may be overkill.. but knowing me i will want more power some day.
I have loads more time with this car compared to the WRX i had.... which will help me financially and hopefully give me more time to research properly.
Anyone want to add anything else??
FMIC or Chargecooler..... Hmmmm
Rob
20 September 2003, 08:53 AM
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Tweenie,
when you say GT is out - as your headers are sorted - which headers do you have?
If you have Gruppe-S or HKS or indeed any headers that fit to the standard position flange then there are options.
Also for 400bhp you don't have to go too big - there are smaller Garretts with inbuilt wastegates to keep things simple.
Also just noticed a comment earlier from aus73 regarding most uprated rods being H-section...
...is this based on the fact that the prettiest rods in the UK aftermarket are H-section; or based on a view that this is the best way to go? Personally I am using I-section beams that look strong enough to hold up the Empire State Building and are proven to figures way beyond 500bhp, and I have seen them in cars running over 500lbs ft.
Rannoch
when you say GT is out - as your headers are sorted - which headers do you have?
If you have Gruppe-S or HKS or indeed any headers that fit to the standard position flange then there are options.
Also for 400bhp you don't have to go too big - there are smaller Garretts with inbuilt wastegates to keep things simple.
Also just noticed a comment earlier from aus73 regarding most uprated rods being H-section...
...is this based on the fact that the prettiest rods in the UK aftermarket are H-section; or based on a view that this is the best way to go? Personally I am using I-section beams that look strong enough to hold up the Empire State Building and are proven to figures way beyond 500bhp, and I have seen them in cars running over 500lbs ft.
Rannoch
21 September 2003, 06:04 AM
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Here a good example of an ported shroud
http://www.takakaira.com/asp/templat...EfFfacBd%60gCb
[Edited by subhks - 9/21/2003 6:04:51 AM]
http://www.takakaira.com/asp/templat...EfFfacBd%60gCb
[Edited by subhks - 9/21/2003 6:04:51 AM]
21 September 2003, 08:34 PM
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Rannoch, they are the OBX supplied headers...
I know the position can still be changed and i will decide fully when the time comes to purchase my turbo.
I think that it will prob come down to price in the end, internal wastegate means.... std up and down pipes and basically no need for any custom piping, but.. if i decide that i want to up the power stakes i may be better off with an ext WG set up and a decent size turbo.
What are your thoughts on the different set ups?? would you say that an ext WG set up would be overkill given my requirements (power)..
Rob
I know the position can still be changed and i will decide fully when the time comes to purchase my turbo.
I think that it will prob come down to price in the end, internal wastegate means.... std up and down pipes and basically no need for any custom piping, but.. if i decide that i want to up the power stakes i may be better off with an ext WG set up and a decent size turbo.
What are your thoughts on the different set ups?? would you say that an ext WG set up would be overkill given my requirements (power)..
Rob
22 September 2003, 12:48 AM
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Tweenie,
I am not sure if your post regarding your internal wastegate comment refers to using standard fit turbos or to an internal Garrett.
All of the Garretts I am aware of will need a Garrett style flange to fit the car. If the OBX has the header flange in the same position as the original headers then a jig is available for making an uppipe.
The GT25 and GT30 are both available with internal wastegate although I am not aware of these being tried on a Scoob.
I have seen external wastegate GT Series turbos run on larger capacity Scoobs - and these have shown some very significant potential.
As Andy says - speak to Mark as he probably has more experience of sorting and trying Garretts for Scoobs than most.
Rannoch
I am not sure if your post regarding your internal wastegate comment refers to using standard fit turbos or to an internal Garrett.
All of the Garretts I am aware of will need a Garrett style flange to fit the car. If the OBX has the header flange in the same position as the original headers then a jig is available for making an uppipe.
The GT25 and GT30 are both available with internal wastegate although I am not aware of these being tried on a Scoob.
I have seen external wastegate GT Series turbos run on larger capacity Scoobs - and these have shown some very significant potential.
As Andy says - speak to Mark as he probably has more experience of sorting and trying Garretts for Scoobs than most.
Rannoch
22 September 2003, 01:50 PM
#54
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yes...
Didnt realise you had external too..
My outlet flange is unused.... must really do something with that before I melt a cv joint
[Edited by David_Wallis - 9/22/2003 1:53:09 PM]
Didnt realise you had external too..
My outlet flange is unused.... must really do something with that before I melt a cv joint
[Edited by David_Wallis - 9/22/2003 1:53:09 PM]
22 September 2003, 01:50 PM
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IIRC Mark mentioned in the past about using a VF exh housing to overcome the mounting prob. Is it H+S that has the jig??
Hope this comment doesnt bring bad comments but... IMHO Christian is not using his Turbo to his full potential and i dont feel that he can be used as an example, IIRC someone else is using a Lat Per VF/garrett hybrid (not harvey)... and getting good results and has been for a while, prob more of a comparison for me (christian has 2.5 etc).
Hope this comment doesnt bring bad comments but... IMHO Christian is not using his Turbo to his full potential and i dont feel that he can be used as an example, IIRC someone else is using a Lat Per VF/garrett hybrid (not harvey)... and getting good results and has been for a while, prob more of a comparison for me (christian has 2.5 etc).
22 September 2003, 05:27 PM
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I know who he is
Thanks for everyones input so far, some interesting stuff here...
Am going to start stripping the WRX engine down this week, am sure to have some funny pics... All will become clear.
Rob
Thanks for everyones input so far, some interesting stuff here...
Am going to start stripping the WRX engine down this week, am sure to have some funny pics... All will become clear.
Rob