Page 3 of 4 FirstFirst 1234 LastLast
Results 41 to 60 of 72

Thread: twin turbo Vs Big single?

  1. #41
    adaxo's Avatar

    Offline
     
    Name
    Adam
    Join Date
    May 2006
    Last Online
    02-03-2024
    Posts
    5,190
    Country
    United Kingdom
    Location
    Worsley
    Car
    EC5W
     
    His FL Legnum VR4 running 238.8 ATW HP and 500Nm @1.05 bar on LPG
    Hers PFL Legnum VR4 COTY see here for full story
    Looking for AMSoil? click here

    living in north west?
    would you like to meet with other VR4 fanatics?
    click here

    My recent and ex Mitsubishi's


  2. #42
    Confused's Avatar

    Online
     
    Name
    Garry
    Join Date
    Apr 2005
    Last Online
    Today
    Membership ID
    714
    Posts
    3,537
    Country
    United Kingdom
    Location
    Notts
    Car
    Legnum VR-4
    My Garage
    Visit
     
    You lose the longer runners (which helps with low down torque) if you do that.
    Last edited by Confused; 03-06-2020 at 02:01 PM. Reason: Making it sound better

  3. #43
    adaxo's Avatar

    Offline
     
    Name
    Adam
    Join Date
    May 2006
    Last Online
    02-03-2024
    Posts
    5,190
    Country
    United Kingdom
    Location
    Worsley
    Car
    EC5W
     
    Quote Originally Posted by Confused View Post
    You lose the longer runners, which helps with low down torque if you do that.
    Sorry this sentence get me confused :-) if I cut off marked part of plenum I do lose low down torque or by removing this improve it?

  4. #44
    Confused's Avatar

    Online
     
    Name
    Garry
    Join Date
    Apr 2005
    Last Online
    Today
    Membership ID
    714
    Posts
    3,537
    Country
    United Kingdom
    Location
    Notts
    Car
    Legnum VR-4
    My Garage
    Visit
     
    Sorry, doing what you suggest, and cutting it out harms low down torque.

  5. #45
    adaxo's Avatar

    Offline
     
    Name
    Adam
    Join Date
    May 2006
    Last Online
    02-03-2024
    Posts
    5,190
    Country
    United Kingdom
    Location
    Worsley
    Car
    EC5W
     
    Makes sense now, well that, so far, just a thought an option may worth to consider or may complete bul##, it just pop in to my head yesterday while looking to engine bay from side and trying visualise what can be done.

  6. #46
    Oblivion's Avatar

    Offline
     
    Name
    Aaron
    Join Date
    Feb 2007
    Last Online
    27-10-2023
    Posts
    794
    Country
    Japan
    Location
    Shimane
    Car
    2000 Galant VR4
     
    Im not sure how its bolts in so excuse me if it sounds daft.... but if you want the throttle body on the other side could you turn the plenum around so that plenum runs over the front bank? It would also make the piping from the intercooler a lot shorter and straighter if it is indeed possible.
    Daily driver / circuit car / drag car / show car / weekend cruiser / project car

  7. #47
    Nick Mann's Avatar

    Offline
     
    Name
    Nick
    Join Date
    Sep 2003
    Last Online
    17-03-2024
    Membership ID
    17
    Posts
    24,895
    Country
    United Kingdom
    Location
    Redditch
    Car
    Legnum type-S
    My Garage
    Visit
     
    I don't think the bonnet would shut. The engine sits flat in the car and the bonnet is lower at the front, so I am fairly certain that this solution would be too high for the front of the bonnet.

    You would have to rotate the inlet manifold too as the bolt pattern between the plenum and the manifold has not got rotational symmetry.

  8. #48
    elnevio's Avatar

    Offline
     
    Name
    Nev
    Join Date
    Dec 2007
    Last Online
    01-03-2024
    Membership ID
    510
    Posts
    17,953
    Country
    United Kingdom
    Location
    Gloucester
    Car
    VR-4+Panda+shed
    My Garage
    Visit
     
    Quote Originally Posted by Nick Mann View Post
    I don't think the bonnet would shut. The engine sits flat in the car and the bonnet is lower at the front, so I am fairly certain that this solution would be too high for the front of the bonnet.

    You would have to rotate the inlet manifold too as the bolt pattern between the plenum and the manifold has not got rotational symmetry.
    Maybe that's the problem this dude was solving!

    October 2023 fleet status: 100% operational


    | Legnum VR-4S | Fiat Panda 100HP !! | a blue one! | Avensis T-180 | VR-4 parts van! |

    Why not become a full member of CVR4 and enjoy the additional benefits membership brings?! Information here.

  9. #49
    Davezj's Avatar

    Offline
     
    Name
    Dave
    Join Date
    Jan 2006
    Last Online
    09-01-2024
    Membership ID
    255
    Posts
    16,245
    Country
    England
    Location
    Manchester
    Car
    VR-4
    My Garage
    Visit
     
    well turbo has turned up and it is massive.

    here are the specs of the turbo.

    Specification :
    Compressor:
    Compressor Trim: 44% (recalculated for measured values (52.86/76.17)² x 100= 48.4%
    Compressor Inducer Diamter: 50.5 mm (52.86mm)
    Compressor Exducer Diamter: 76 mm (measured 76.17mm)
    Compressor A/R: 0.5

    Turbine :
    Turbocharger Exhaust (Turbo Manifold) Flange: T3 T4 4 bolt Flange Patterns
    Exhaust (Downpipe) Flange: V-Band Flange
    Turbine Trim:73% (recalculated for measured values (55.85/65.23)² x 100= 73.3%
    Turbine Inducer Diamter: 65.5 mm measured 65.23mm)
    Turbine Exducer Diamter: 55.9 mm (measured 55.85mm)
    Turbine A/R: 0.63

    here are some pictures of the turbo and a little strip down and inspection/measurement.

    IMG_20200604_172215.jpgIMG_20200604_162257.jpgIMG_20200604_162247.jpgIMG_20200604_162238.jpgIMG_20200604_162213.jpgIMG_20200604_162204.jpgIMG_20200604_162143.jpgIMG_20200604_162137.jpgIMG_20200604_162124.jpgIMG_20200604_162045.jpg

    these are some picture of the turbine and compressor wheels and the measurement of them.

    IMG_20200604_163004.jpgIMG_20200604_164029.jpgIMG_20200604_164018.jpgIMG_20200604_164004.jpgIMG_20200604_163819.jpgIMG_20200604_163256.jpgIMG_20200604_163216.jpgIMG_20200604_163026.jpgIMG_20200604_163020.jpgIMG_20200604_163013.jpg

    IMG_20200604_165051.jpgIMG_20200604_165042.jpgIMG_20200604_165028.jpgIMG_20200604_165019.jpgIMG_20200604_165012.jpgIMG_20200604_165001.jpgIMG_20200604_164945.jpgIMG_20200604_164120.jpgIMG_20200604_164107.jpgIMG_20200604_164058.jpg

    IMG_20200604_165110.jpgIMG_20200604_165116.jpgIMG_20200604_165123.jpgIMG_20200604_165133.jpgIMG_20200604_165142.jpgIMG_20200604_170300.jpgIMG_20200604_170345.jpgIMG_20200604_170403.jpgIMG_20200604_170411.jpgIMG_20200604_170424.jpg


    IMG_20200604_170521.jpgIMG_20200604_170542.jpgIMG_20200604_172308.jpg

    Bye for Now!

  10. #50
    adaxo's Avatar

    Offline
     
    Name
    Adam
    Join Date
    May 2006
    Last Online
    02-03-2024
    Posts
    5,190
    Country
    United Kingdom
    Location
    Worsley
    Car
    EC5W
     
    Can it be twisted? as looks like it has oil return on wrong side.

  11. #51
    Confused's Avatar

    Online
     
    Name
    Garry
    Join Date
    Apr 2005
    Last Online
    Today
    Membership ID
    714
    Posts
    3,537
    Country
    United Kingdom
    Location
    Notts
    Car
    Legnum VR-4
    My Garage
    Visit
     
    That'll be a fun toy!
    Personally, I'd be looking for a turbo without an integrated wastegate for my final installation...

    That however looks a little like the one that Stav-Tech has just done some porting on - could get a few gains on that turbo after a couple of hours with an angry end (aka a die grinder)

    https://youtu.be/kAYe8Cjz2wI

  12. #52
    Davezj's Avatar

    Offline
     
    Name
    Dave
    Join Date
    Jan 2006
    Last Online
    09-01-2024
    Membership ID
    255
    Posts
    16,245
    Country
    England
    Location
    Manchester
    Car
    VR-4
    My Garage
    Visit
     
    Yes you can clock it any way you want on the compressor side and the turbine side.

  13. #53
    Davezj's Avatar

    Offline
     
    Name
    Dave
    Join Date
    Jan 2006
    Last Online
    09-01-2024
    Membership ID
    255
    Posts
    16,245
    Country
    England
    Location
    Manchester
    Car
    VR-4
    My Garage
    Visit
     
    Quote Originally Posted by Confused View Post
    That'll be a fun toy!
    Personally, I'd be looking for a turbo without an integrated wastegate for my final installation...

    That however looks a little like the one that Stav-Tech has just done some porting on - could get a few gains on that turbo after a couple of hours with an angry end (aka a die grinder)

    https://youtu.be/kAYe8Cjz2wI
    It will need the wastegate hole enlarging and a divot put in the plate behind the wastegate flap to allow it to open Futher. But that is about it.


    I would want to see how it works first before doing anything else to it. And removing it would be so simple after install as it is just sat on top of the gear box. Well the gear box mount.

    It would only be a play test turbo really, for longevity and reliability I would think I would be looking to buy an holder hx35. I think the port placement on the turbo is the same as the hx35. It should be a direct swap out. Like for like.
    It will be an interesting thing to design and play with.

    But I have to finish the engine rebuild on the black vr4 first. But I have all the bits for that now so it is time to crack on.

  14. #54
    Davezj's Avatar

    Offline
     
    Name
    Dave
    Join Date
    Jan 2006
    Last Online
    09-01-2024
    Membership ID
    255
    Posts
    16,245
    Country
    England
    Location
    Manchester
    Car
    VR-4
    My Garage
    Visit
     
    The runner length is not an issue on turbo charged cars it only really effect non turbo engines. The changes are very very minimal if any on a turbo car.

  15. #55

    Offline
     
    Name
    Samppa
    Join Date
    Apr 2020
    Last Online
    04-01-2023
    Posts
    13
    Country
    Other
    Car
    EJ8 Civic
     
    Quote Originally Posted by Davezj View Post
    The runner length is not an issue on turbo charged cars it only really effect non turbo engines. The changes are very very minimal if any on a turbo car.
    I have to disagree on runner length effect, the effect is still there despite the extra pressure in the intake. Air velocity creates pressure waves as intake valve closes it bounces from there back to plenum and from there back to valve, the key is to have right length runner so the wave arrives to the intake valve as it opens. As far as i know the pressure created by turbo doesn't affect this physics law.
    Dyno comparison with long runner intake vs short runner in turbocharged Honda
    That's just for example, there are more comparisons out there, but the point is that the difference can be up to 5% in the power and of course big effect for the power/torque rpm range.

  16. #56
    Davezj's Avatar

    Offline
     
    Name
    Dave
    Join Date
    Jan 2006
    Last Online
    09-01-2024
    Membership ID
    255
    Posts
    16,245
    Country
    England
    Location
    Manchester
    Car
    VR-4
    My Garage
    Visit
     
    I am not debating different manifolds give better inlet air flow on turbo changed cars.
    however in the honda thread they have changed the entire inlet plenum they have not just changed inlet runner length. it is like comparing apple and oranges, yes they are both fruit and i would not argue with the fact the apples probably make better cider.

  17. #57

    Offline
     
    Name
    Samppa
    Join Date
    Apr 2020
    Last Online
    04-01-2023
    Posts
    13
    Country
    Other
    Car
    EJ8 Civic
     
    Of course plenum size effect is also there (Plenum size doesn't effect nearly as much as runner lenght and diameter), but this comparison is between this edelbrock victor x this is known for it's short runners and it is made for high revving racing engines, and the compared intake manifold is Skunk2 pro this is kind of straight copy of Integra type r intake manifold (normal street engine), wich have longer runners than the edelbrock intake manifold.
    Just saying this, after all this thread is about gaining power.

    Then for the optimum lenght of the runner also the intake cam duration plays a big role, for the stock cam standard manifold lenght is pretty close optimum, but if you have intake cams with longer duration the intake pulse have less time to travel back to intake valve. So again there you need shorter runners.
    Runner diameter determines the pulse "power" smaller diameter works great in the low rpm range as it creates greater velocity to increase the pulse effect, but in the higher rpm:s small diameter is a restriction and larger diameter is needet.

    And then the plenum size is pretty close to optimum when the size is near the engine displacement. For the 6A13TT it would be 2.5L

  18. #58
    Davezj's Avatar

    Offline
     
    Name
    Dave
    Join Date
    Jan 2006
    Last Online
    09-01-2024
    Membership ID
    255
    Posts
    16,245
    Country
    England
    Location
    Manchester
    Car
    VR-4
    My Garage
    Visit
     
    Personally i was under the impression that for a turbo car the runner length made a slight difference. but in a non turbo car it make a big difference because there is not the force pushing the air into the engine.This is why variable inlet length was such a big thing before all the manufactures swapped over to turbo charging there engines and then it was dropped. Now they are trying to make the cars more and more efficient they have started to use variable length runners again, well just a flap to have long and short depending on RPM. the variable length runner has such marginal gains when you are taking about changing you boost from 1 bar to 2 bar and still staying in a 74% efficiency area of your compressor map it is not worth worrying about.


    you would probably get more of a gain and more evenly distributed air flow at high demand times if the plenum was longer between throttle body and No 6 and then tapered off to a smaller diameter towards the No1 cylinder to ensure each runner got the same amount of air atthe same pressure as the number 2 3 4 5 runners in the middle. but it doesn't.
    air does not like turning sharp corner which is why the no 6 runner is probably staved of air a bit and by the time the air has gone from the throttle body to the number 1 runner as all the other cylinders have taken as much air out of that flow in the plenum as they can and the remaining air has slowed down its movement and caused a small pressure drop at the number 1 runner end of the plenum. this is why almost every turbo inlet plenum tapers to the opposite end to the throttle body to keep the flow constant to all the runners.
    but this is only really an issue when the turbos can't produce enough air to feed the engine at higher revs, and no matter what you set the boost to it keeps dropping off at the high end. which is what happens with our little turbos.

    you would imagine the plenum size should be at the back of the throttle body next to runner 6 about 7 times the runner diameter and narrows to 6 times runner diameter at runner 5 and so on until you get to runner 1 where the plenum should be about 2 times the runner diameter. each runner takes a runners diameter of air from the plenum. you can't view the plenum as a static sealed volume and apply Boyle's law because it is not sealed chamber at least 2 valves are open at any one time so the air in the plenum is constantly moving, at 7000rpm the engine turns two revolution every 17ms which is for 6 cylinder and is the full 4 stroke cycle so for each cylinders valves, the inlet stroke lasts for 4.25ms. as the firing order for the engine is 1,2,3,4,5,6,1 the inlet strokes have to be 1,2,3,4,5,6,1 so runner one suck 1 diameter of air then runner 2 sucks 1 diameter of air then runner 3 sucks 1 diameter of air and so on which is why i added the 1 diameter extra to the plenum size to allow the volume of air to be replenished at the no 1 runner once the number 6 runner as taken it share.

    but hey what do i know this is just a theory. waffle, waffle, ramble, ramble.

    but doing this, changing the plenum chamber size and shape will probably do nothing to increase actual air flow into the engine as you have not changed the size of the hole going into the inlet valves, it might ensure there is enough air available to get a full flow of air to the inlet valve but it will not increase it to any more than is going to the number 2,3,4,5 runners in the middle just equal it out a bit. it is a lot of work for not much gain if anything at all.
    Last edited by Davezj; 10-06-2020 at 10:27 PM.

  19. #59

    Offline
     
    Name
    Samppa
    Join Date
    Apr 2020
    Last Online
    04-01-2023
    Posts
    13
    Country
    Other
    Car
    EJ8 Civic
     
    Quote Originally Posted by Davezj View Post
    Personally i was under the impression that for a turbo car the runner length made a slight difference. but in a non turbo car it make a big difference because there is not the force pushing the air into the engine.This is why variable inlet length was such a big thing before all the manufactures swapped over to turbo charging there engines and then it was dropped. Now they are trying to make the cars more and more efficient they have started to use variable length runners again, well just a flap to have long and short depending on RPM. the variable length runner has such marginal gains when you are taking about changing you boost from 1 bar to 2 bar and still staying in a 74% efficiency area of your compressor map it is not worth worrying about.
    Yes of course you can make more power by raising boost pressure but still it doesn't change the fact that if you have tuned intake runner length with 1 bar of boost VS some random length runner with same boost pressure you would make more power.
    And as you mentioned even some standard new turbo charged cars come with variable length intake runners, this is usually a good sign that this is working concept.
    Runner pressure waves works with harmonics, sometimes short runner might work in the low rpm range and high rpm range but not in the middle. (First, second or even third harmonics, as how many times the wave bounces back and forward before the valve opens).
    As said the harmonics work the same way still if we got boost pressure only difference is that air molecules are packed tighter.
    Example of Hyundai VIS system that is used also in the present 1.4 T-GDI turbo engine

    Quote Originally Posted by Davezj View Post
    you would probably get more of a gain and more evenly distributed air flow at high demand times if the plenum was longer between throttle body and No 6 and then tapered off to a smaller diameter towards the No1 cylinder to ensure each runner got the same amount of air at the same pressure as the number 2 3 4 5 runners in the middle. but it doesn't.
    air does not like turning sharp corner which is why the no 6 runner is probably staved of air a bit and by the time the air has gone from the throttle body to the number 1 runner as all the other cylinders have taken as much air out of that flow in the plenum as they can and the remaining air has slowed down its movement and caused a small pressure drop at the number 1 runner end of the plenum. this is why almost every turbo inlet plenum tapers to the opposite end to the throttle body to keep the flow constant to all the runners.
    but this is only really an issue when the turbos can't produce enough air to feed the engine at higher revs, and no matter what you set the boost to it keeps dropping off at the high end. which is what happens with our little turbos.

    you would imagine the plenum size should be at the back of the throttle body next to runner 6 about 7 times the runner diameter and narrows to 6 times runner diameter at runner 5 and so on until you get to runner 1 where the plenum should be about 2 times the runner diameter. each runner takes a runners diameter of air from the plenum. you can't view the plenum as a static sealed volume and apply Boyle's law because it is not sealed chamber at least 2 valves are open at any one time so the air in the plenum is constantly moving, at 7000rpm the engine turns two revolution every 17ms which is for 6 cylinder and is the full 4 stroke cycle so for each cylinders valves, the inlet stroke lasts for 4.25ms. as the firing order for the engine is 1,2,3,4,5,6,1 the inlet strokes have to be 1,2,3,4,5,6,1 so runner one suck 1 diameter of air then runner 2 sucks 1 diameter of air then runner 3 sucks 1 diameter of air and so on which is why i added the 1 diameter extra to the plenum size to allow the volume of air to be replenished at the no 1 runner once the number 6 runner as taken it share.

    but hey what do i know this is just a theory. waffle, waffle, ramble, ramble.

    but doing this, changing the plenum chamber size and shape will probably do nothing to increase actual air flow into the engine as you have not changed the size of the hole going into the inlet valves, it might ensure there is enough air available to get a full flow of air to the inlet valve but it will not increase it to any more than is going to the number 2,3,4,5 runners in the middle just equal it out a bit. it is a lot of work for not much gain if anything at all.
    I really haven't dig down deep in to plenum design, but as you said the style where the plenum is made smaller from the other end of the throttle body is known for it's positive effect for the power.
    There is also this strange plenum over plenum styled things (I don't know what they are called), but these do work very well at distributing air evenly to all cylinders. One example of this design

    I do enjoy talking about these kind of topics as engineer, and i'm all open for designs and other valid data if it's proven some how.
    Other wise if someone just says that this doesn't work without any proof or theory behind it, i really can''t believe that.

    Edit: Sorry if this is too far of topic.
    Last edited by Tuopponen; 11-06-2020 at 09:14 AM.

  20. #60
    Davezj's Avatar

    Offline
     
    Name
    Dave
    Join Date
    Jan 2006
    Last Online
    09-01-2024
    Membership ID
    255
    Posts
    16,245
    Country
    England
    Location
    Manchester
    Car
    VR-4
    My Garage
    Visit
     
    the issue is if you want to fit a big single turbo, it look like we are probably going to have to modify the plenum chamber, how you do it is up to you. but the throttle body is probably going to have to move to make room for the exhaust and manifold exit to come up and over the gear box at the back of the engine.

    we might be able to fit it all in but it will be very tight, and all the other single turbo conversions i have seen of our cars have modified the plenum and moved the throttle body.

Page 3 of 4 FirstFirst 1234 LastLast

Similar Threads

  1. Single vs Twin Turbo
    By bradc in forum Turbos, Exhaust & Induction
    Replies: 30
    Last Post: 23-10-2009, 08:53 PM
  2. twin Vs Single turbo's
    By Oggie in forum Turbos, Exhaust & Induction
    Replies: 41
    Last Post: 29-07-2008, 10:06 PM
  3. Single vs Twin turbo setup
    By Kenneth in forum Turbos, Exhaust & Induction
    Replies: 12
    Last Post: 29-08-2007, 10:34 PM
  4. Twin Turbo - 2 Single Turbo
    By zentac in forum Turbos, Exhaust & Induction
    Replies: 121
    Last Post: 13-06-2006, 11:51 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •