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Re: I was then I wasnt....
[Re: Rudidudi]
#1395818
03/12/2012 22:35
03/12/2012 22:35
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Marco20ValveT
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Marco20ValveT
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Re: I was then I wasnt....
[Re: nick_d]
#1395841
03/12/2012 23:46
03/12/2012 23:46
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Joined: Aug 2010
Posts: 141 East yorkshire
sherlock
On a journey
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On a journey
Joined: Aug 2010
Posts: 141
East yorkshire
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The thing I can't understand is if the large turbo feeds the small one, surely this will limit top end power??..... Obviously not though!! Infact I thought it was the exact OPPOSITE to that (small feeding large)..!! Clever Sh*t.... !!
Nick Thats what the two 46mm wastegates are for, at higher engine speeds there opening up letting the pressure out of the exhaust manifold effectively by-passing the small turbine housing
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Re: I was then I wasnt....
[Re: Rudidudi]
#1395853
04/12/2012 02:56
04/12/2012 02:56
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Joined: Nov 2006
Posts: 1,580 Melbourne, Australia
Scuderia
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My life on the forum
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Melbourne, Australia
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Very interesting, well done! Which turbos are you using and what wastegate settings have you set? Are you compounding the boost at all?
Last edited by Scuderia; 04/12/2012 03:24.
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Re: I was then I wasnt....
[Re: Rudidudi]
#1395875
04/12/2012 09:35
04/12/2012 09:35
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Joined: Dec 2005
Posts: 12,296 Sandhurst
Begbie
ex El Presidente
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ex El Presidente
I AM a Coop
Joined: Dec 2005
Posts: 12,296
Sandhurst
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Phil, correct me if this is wrong, but this is how I think you have your setup at the moment? I also think it will help others get their head around how you have set it up too. I think I might have the wastegate off the small turbo exhaust housing wrong?
Your car is Usain Bolt with wellies
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Re: I was then I wasnt....
[Re: Begbie]
#1395900
04/12/2012 11:51
04/12/2012 11:51
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Marco20ValveT
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Marco20ValveT
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Square pistons Alexis No, spark plug cover, duh! HA
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Re: I was then I wasnt....
[Re: Rudidudi]
#1395903
04/12/2012 12:16
04/12/2012 12:16
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Joined: Dec 2005
Posts: 10,729 N.E Scotland
mattB
Club member 6
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Club member 6
I AM a Coop
Joined: Dec 2005
Posts: 10,729
N.E Scotland
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New thread required.........
Death-rattle-tastic
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Re: I was then I wasnt....
[Re: Scuderia]
#1396060
05/12/2012 00:25
05/12/2012 00:25
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Joined: Aug 2010
Posts: 141 East yorkshire
sherlock
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On a journey
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Very interesting, well done! Which turbos are you using and what wastegate settings have you set? Are you compounding the boost at all? Its the standard t28 and a T3/T04b H-Trim, there both set to run 18psi at there respective wastegates , and yeah its compounding. Its a bit difficult to explain how its working, there not running 18psi at the same time. If you feed 18psi into a turbo thats already boosting at 18psi it doesnt add to it the pressure ratios multiply, so as a PR of roughly 2.25:1(18psi) feeding into a turbo already running with a PR of 2.25:1(18psi) would give a final pressure ratio at the manifold of 4.5:1(54psi). So the small turbo spools to give a manifold pressure of 18psi at 2700rpm, at about 3200rpm the big turbo starts making boost - not alot but enough to get the manifold pressure upto 26psi at around 3600rpm and it's holding 26psi up to 7200rpm as a high boost setting. Its setup up so as the PR of the big turbo goes up the PR of the small turbo goes right down so I can keep the boost at sensible levels
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Re: I was then I wasnt....
[Re: sherlock]
#1396100
05/12/2012 09:42
05/12/2012 09:42
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Joined: Dec 2005
Posts: 12,296 Sandhurst
Begbie
ex El Presidente
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ex El Presidente
I AM a Coop
Joined: Dec 2005
Posts: 12,296
Sandhurst
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Phil, correct me if this is wrong, but this is how I think you have your setup at the moment? I also think it will help others get their head around how you have set it up too. I think I might have the wastegate off the small turbo exhaust housing wrong? The induction part is right, the wastegates feed into the big turbo not into downpipe Couldn't you use the 2nd wastegate off the manifold rather than having to weld something off the exhaust turbine?
Your car is Usain Bolt with wellies
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Re: I was then I wasnt....
[Re: Rudidudi]
#1396110
05/12/2012 10:42
05/12/2012 10:42
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Marco20ValveT
Unregistered
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Marco20ValveT
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Sherlock - what management system are you using??
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Re: I was then I wasnt....
[Re: Nigel]
#1396117
05/12/2012 11:08
05/12/2012 11:08
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Joined: Dec 2005
Posts: 12,296 Sandhurst
Begbie
ex El Presidente
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ex El Presidente
I AM a Coop
Joined: Dec 2005
Posts: 12,296
Sandhurst
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Are the two turbos in sequence? ie does the already-compressed air feed into the compressor housing of the second turbo, or is it that each turbo feeds the engine directly Refer to my mickey mouse diagram Air filter -> large turbo compressor -> intercooler -> small turbo compressor -> intercooler -> inlet manifold
Your car is Usain Bolt with wellies
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Re: I was then I wasnt....
[Re: sherlock]
#1396128
05/12/2012 11:47
05/12/2012 11:47
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group5lancia
Unregistered
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group5lancia
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Very interesting, well done! Which turbos are you using and what wastegate settings have you set? Are you compounding the boost at all? Its the standard t28 and a T3/T04b H-Trim, there both set to run 18psi at there respective wastegates , and yeah its compounding. Its a bit difficult to explain how its working, there not running 18psi at the same time. If you feed 18psi into a turbo thats already boosting at 18psi it doesnt add to it the pressure ratios multiply, so as a PR of roughly 2.25:1(18psi) feeding into a turbo already running with a PR of 2.25:1(18psi) would give a final pressure ratio at the manifold of 4.5:1(54psi). So the small turbo spools to give a manifold pressure of 18psi at 2700rpm, at about 3200rpm the big turbo starts making boost - not alot but enough to get the manifold pressure upto 26psi at around 3600rpm and it's holding 26psi up to 7200rpm as a high boost setting. Its setup up so as the PR of the big turbo goes up the PR of the small turbo goes right down so I can keep the boost at sensible levels In practice, in the configuration you are using, because all the air getting to the engine has to flow through the first turbo's compressor, isn't the potential power output of the engine limited, not by the theoretically possible pressure ratio attainable through compounding, but by the mass flow that the first turbo's compressor can handle? i.e. the limiting factor is the maximum mass flow of the T28. This is a question - not a criticism of your impressive efforts!
Last edited by group5lancia; 05/12/2012 11:49.
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Re: I was then I wasnt....
[Re: ]
#1396169
05/12/2012 13:27
05/12/2012 13:27
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Joined: Nov 2006
Posts: 1,580 Melbourne, Australia
Scuderia
My life on the forum
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My life on the forum
Joined: Nov 2006
Posts: 1,580
Melbourne, Australia
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In practice, in the configuration you are using, because all the air getting to the engine has to flow through the first turbo's compressor, isn't the potential power output of the engine limited, not by the theoretically possible pressure ratio attainable through compounding, but by the mass flow that the first turbo's compressor can handle? i.e. the limiting factor is the maximum mass flow of the T28.
This is a question - not a criticism of your impressive efforts!
No, not as you are suggesting anyway as the pressure ratio and CFM is very low, well under the limit for the turbo. Adding the big turbo does not change these parameters. It would be like fitting a turbo to an N/A engine but leaving the wastegate open so it does not make any boost. So there is a minor restriction there but not in the usual sense. And since this turbo is then effectively turbocharged any restriction is easily overcome with boost.
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Re: I was then I wasnt....
[Re: Begbie]
#1396465
06/12/2012 19:16
06/12/2012 19:16
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Joined: Aug 2010
Posts: 141 East yorkshire
sherlock
On a journey
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On a journey
Joined: Aug 2010
Posts: 141
East yorkshire
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Phil, correct me if this is wrong, but this is how I think you have your setup at the moment? I also think it will help others get their head around how you have set it up too. I think I might have the wastegate off the small turbo exhaust housing wrong? The induction part is right, the wastegates feed into the big turbo not into downpipe Couldn't you use the 2nd wastegate off the manifold rather than having to weld something off the exhaust turbine? Not sure what you mean, both of those wastegates are working together doing the same thing at the same time. Think of it as one big wastegate controlling the boost of the small turbo
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Re: I was then I wasnt....
[Re: Nigel]
#1396466
06/12/2012 19:19
06/12/2012 19:19
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Joined: Aug 2010
Posts: 141 East yorkshire
sherlock
On a journey
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On a journey
Joined: Aug 2010
Posts: 141
East yorkshire
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So - the first wastegate off the manifold is enough to prevent the turbine housing on the small turbo becoming a restriction? No, I tried it with one wastegate and it didn't work the boost was creeping up under load
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Re: I was then I wasnt....
[Re: ]
#1396470
06/12/2012 19:42
06/12/2012 19:42
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Joined: Aug 2010
Posts: 141 East yorkshire
sherlock
On a journey
|
On a journey
Joined: Aug 2010
Posts: 141
East yorkshire
|
In practice, in the configuration you are using, because all the air getting to the engine has to flow through the first turbo's compressor, isn't the potential power output of the engine limited, not by the theoretically possible pressure ratio attainable through compounding, but by the mass flow that the first turbo's compressor can handle? i.e. the limiting factor is the maximum mass flow of the T28.
This is a question - not a criticism of your impressive efforts!
The short answer is - I dont know! I guess at some point it may become a restriction but I dont think i'll ever get it to the point where I need to think about changing anything
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