MakeEverything
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 posted on 15/12/09 at 10:26 PM |
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Found this. Opinions...?
I found this;
http://i68.photobucket.com/albums/i17/paulvolk/twinturbo_large.jpg
Anyone got any opinions? Mine is that by closing the exhaust loop from the manifold mounted turbo, it prevents the wastegate from operating
effectively, thus preventing the system from depressurising correctly???
Not planning anything, just curious to hear opinions.
Kindest Regards,
Richard.
...You can make it foolProof, but youll never make it Idiot Proof!...
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blakep82
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| posted on 15/12/09 at 10:28 PM |
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if i'm understanding that right, i bet the turbo lag would be terrible!
________________________
IVA manual link http://www.businesslink.gov.uk/bdotg/action/detail?type=RESOURCES&itemId=1081997083
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l0rd
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| posted on 15/12/09 at 10:30 PM |
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This is a serial setup and would be a killer.
I love it.
Turbo lag should be minimal
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MakeEverything
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| posted on 15/12/09 at 10:30 PM |
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I think the objective was to reduce lag, by installing different size turbos, with the larger one producing more boost than the smaller one. Not sure
how effective it would be mind...
I cant see how the pressure is releived though once the throttle is closed? The wastegate will operate, but it doesnt go anywhere other than into the
circuit again.
Kindest Regards,
Richard.
...You can make it foolProof, but youll never make it Idiot Proof!...
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blakep82
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| posted on 15/12/09 at 10:33 PM |
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i'd have thought you'd end up waiting for one turbo to spin up before the other one starts to spin up? i'd have thought 2 different
size turbos in 'parallel' would have been better, because as you wait for the big one, the small ones already picked up some of the work
________________________
IVA manual link http://www.businesslink.gov.uk/bdotg/action/detail?type=RESOURCES&itemId=1081997083
don't write OT on a new thread title, you're creating the topic, everything you write is very much ON topic!
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StrikerChris
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| posted on 15/12/09 at 10:49 PM |
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i cant get my head round that!might be the beer!is the wastegate exhausting into a screamer pipe?and just using one turb to try and keep the other one
constantly spinning for no lag?must of cost a fair bit whatever it achieves!
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l0rd
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| posted on 15/12/09 at 10:54 PM |
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quote:
Originally posted by blakep82
i'd have thought you'd end up waiting for one turbo to spin up before the other one starts to spin up? i'd have thought 2 different
size turbos in 'parallel' would have been better, because as you wait for the big one, the small ones already picked up some of the work
This i believe is serial.
One small turbo is prety much constantly on and the large one gives the big boost.
The parallel one are normaly on V type engines
[Edited on 15/12/09 by l0rd]
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Volvorsport
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| posted on 15/12/09 at 10:56 PM |
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as above , its in serial for lots of boost ie 60-100 psi .
a method employed in tractor pulling so can achieve the high boost and make the power band wider , compared to one single turbo making the boost .
the wastegate would work as normal - that is just a bypass of the turbine wheel to slow it down .
Older diesels ran without a wastegate since the turbos werent small enough to spool early to create overboosting problems , and diesels are tolerant
of varying AFR .
More fuel makes more power , so as long as you dont force so much compressed air that effectively overcomes the mechanical strength of the engine your
good to go .
www.dbsmotorsport.co.uk
getting dirty under a bus
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MikeRJ
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| posted on 15/12/09 at 10:56 PM |
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quote:
Originally posted by blakep82
i'd have thought you'd end up waiting for one turbo to spin up before the other one starts to spin up? i'd have thought 2 different
size turbos in 'parallel' would have been better, because as you wait for the big one, the small ones already picked up some of the work
But then you'd be losing most of the exhaust pressure through the large turbo (i.e. path of least resistance).
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StrikerChris
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| posted on 15/12/09 at 11:33 PM |
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and if its not enough boost there'll be enough derv cooling the pistons the smoke screen will hide you loosing! Carefully aimed exhaust is the
key!
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hillbillyracer
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| posted on 16/12/09 at 12:45 AM |
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quote:
Originally posted by Volvorsport
More fuel makes more power , so as long as you dont force so much compressed air that effectively overcomes the mechanical strength of the engine your
good to go .
Sometimes the tractor puller lads manage to do exactly this, like the block splitting between the main bearings & the bores for the entire length
of it. That kinda thing will happens now & then if you fit a few turbos in a row to get an engine producing 10 times it's factory output!
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Liam
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| posted on 16/12/09 at 11:11 AM |
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quote:
Originally posted by MakeEverything
I cant see how the pressure is releived though once the throttle is closed? The wastegate will operate, but it doesnt go anywhere other than into the
circuit again.
Think you may be getting your wastegates and dump valves mixed up. It's a dump valve, in the inlet air plumbing, which opens when the throttle
is closed to relieve inlet pressure. This being a diesel, which doesn't have a throttle to close, probably doesn't need one.
The wastegates in this system will do what wastegates always do - regulate boost by bypassing exhaust flow away from the turbines according to their
setting. These turbos look to have internal wastegates as is most common.
Liam
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wilkingj
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| posted on 16/12/09 at 12:23 PM |
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Ha!.. Diesels do not have a throttle butterfly.
They are just an open tube.
The throttle pedal is connected to the Injector pump and just pumps in more fuel.
Hence the overpressurisation on no throttle is not a problem on a diesel.
Well thats how my land rover worked. These new fangled common rail diesels may be different.
Its the same reason why they have a belt driven vacuum pump for the servo brakes. as there was no throttle butterfly to close to create the vacuum
needed by the brakes..
You lot are just Petrolheads
Us Diseasel Heads are a separate breed alltogether
1. The point of a journey is not to arrive.
2. Never take life seriously. Nobody gets out alive anyway.
Best Regards
Geoff
http://www.v8viento.co.uk
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will121
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| posted on 16/12/09 at 12:41 PM |
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i cant see tha picture as blocked at work but is the system set up simular to the new Saab twin turbo principal??
Saab TTid
engine
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MakeEverything
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| posted on 16/12/09 at 03:26 PM |
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quote:
Originally posted by wilkingj
Ha!.. Diesels do not have a throttle butterfly.
They are just an open tube.
The throttle pedal is connected to the Injector pump and just pumps in more fuel.
Hence the overpressurisation on no throttle is not a problem on a diesel.
Well thats how my land rover worked. These new fangled common rail diesels may be different.
Its the same reason why they have a belt driven vacuum pump for the servo brakes. as there was no throttle butterfly to close to create the vacuum
needed by the brakes..
You lot are just Petrolheads
Us Diseasel Heads are a separate breed alltogether
Just as well, because i know next to fk all about diesels!!
Kindest Regards,
Richard.
...You can make it foolProof, but youll never make it Idiot Proof!...
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MakeEverything
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| posted on 16/12/09 at 03:28 PM |
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quote:
Originally posted by Liam
quote:
Originally posted by MakeEverything
I cant see how the pressure is releived though once the throttle is closed? The wastegate will operate, but it doesnt go anywhere other than into the
circuit again.
Think you may be getting your wastegates and dump valves mixed up. It's a dump valve, in the inlet air plumbing, which opens when the throttle
is closed to relieve inlet pressure. This being a diesel, which doesn't have a throttle to close, probably doesn't need one.
The wastegates in this system will do what wastegates always do - regulate boost by bypassing exhaust flow away from the turbines according to their
setting. These turbos look to have internal wastegates as is most common.
Liam
But when the throttle closes, the pressure increases until the turbo slows down and stops producing boost. In this instance, the actuator is operated
by the inlet pressure, which opens the wastegate, so no im not getting them mixed up, just probably not explaining myself properly.
Kindest Regards,
Richard.
...You can make it foolProof, but youll never make it Idiot Proof!...
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westy turbo
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| posted on 16/12/09 at 04:04 PM |
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Fit a Variable geometry turbocharger ,and forget about lag 
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boggle
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| posted on 16/12/09 at 04:58 PM |
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completely pointless imho.....
mazda have a nice twin turbo setup on there rx7, but with the posted picture your smaller turbo has a smaller a/r on the inlet so will start to
restrict the bigger turbo....would have been better running parralell than in series with a nice anti lag system....
just my opinion thou.....
just because you are a character, doesnt mean you have character....
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boggle
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| posted on 16/12/09 at 05:01 PM |
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quote:
Originally posted by MakeEverything
quote:
Originally posted by Liam
quote:
Originally posted by MakeEverything
I cant see how the pressure is releived though once the throttle is closed? The wastegate will operate, but it doesnt go anywhere other than into the
circuit again.
Think you may be getting your wastegates and dump valves mixed up. It's a dump valve, in the inlet air plumbing, which opens when the throttle
is closed to relieve inlet pressure. This being a diesel, which doesn't have a throttle to close, probably doesn't need one.
The wastegates in this system will do what wastegates always do - regulate boost by bypassing exhaust flow away from the turbines according to their
setting. These turbos look to have internal wastegates as is most common.
Liam
But when the throttle closes, the pressure increases until the turbo slows down and stops producing boost. In this instance, the actuator is operated
by the inlet pressure, which opens the wastegate, so no im not getting them mixed up, just probably not explaining myself properly.
if the wastegate opened on over run you would sill get compressor stall, the air is blocked by the butterfly in the throttle body so it just builds up
and stalls the compressor wheel....the waste gate only allows exhaust gas to bypass the outlet turbine to stop overboosting....
just because you are a character, doesnt mean you have character....
for all your bespoke parts, ali welding, waterjet, laser, folding, turning, milling, composite work, spraying, anodising and cad drawing....
u2u me for details
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ss1turbo
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| posted on 16/12/09 at 08:09 PM |
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The new (not even sure if its launched yet) BMW diesel V8 has sequential turbocharging, but knowing BMW, there's going to be a bypass valve in
there somewhere to let more air into the bigger one when the smaller one has run out of puff..
Long live RWD...
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