Results 1 to 31 of 31

Thread: Opinions/Knowledge on Triple SU's

  1. #1
    Dats a Nissan Enthusiast kyteler's Avatar
    Member ID
    CZCC-4758
    Join Date
    Aug 2003
    Location
    Invercargill, New Zealand
    Posts
    635

    Default Opinions/Knowledge on Triple SU's

    Hey guys,

    I'm curious is a triple SU setup for an L24 worth the bother??

    There's a manifold and some roundtops to go with it up for sale and I'm curious as to whether it would actually be worth the time and money and if so, how much would you pay for such a thing?
    -Michael

    1963 Prince Skyline S21D-4
    1973 Datsun 240K Hardtop KHGC110-002286
    1973 Datsun 240K Hardtop KHGC110-003345 (Parts Car) <- Now deceased

  2. #2
    Z fever Fun_in_my_z's Avatar
    Member ID
    CZCC-5338
    Join Date
    Nov 2003
    Location
    Arkansas
    Posts
    3,965
    Blog Entries
    1

    Default

    I would expet paying atleast 100 bucks.
    As far as power gose i wouldnt know. But they look great!
    HLS30-217804 6/75 "The Unnatural One"

    One
    Big
    Ass
    Mistake
    America

  3. #3
    The Lone Potter v12horse's Avatar
    Member ID
    CZCC-3738
    Join Date
    Mar 2003
    Location
    Fremont, Ca
    Age
    36
    Posts
    1,130

    Default

    I have only seen triple su's on an e-type Jaguar. Does the article specify that it is for a L-series engine?
    "A real sports car chooses its owner because it has a soul. If you're chosen, you'll love it, and the more it requires care and maintenance the more you love it." -Mr. Morita (Z432 owner)

    RLS30-034436
    305 GP Light Blue

  4. #4
    Z fever Fun_in_my_z's Avatar
    Member ID
    CZCC-5338
    Join Date
    Nov 2003
    Location
    Arkansas
    Posts
    3,965
    Blog Entries
    1

    Default

    You can get em on a L series engine. But how easy is it?
    HLS30-217804 6/75 "The Unnatural One"

    One
    Big
    Ass
    Mistake
    America

  5. #5
    Dats a Nissan Enthusiast kyteler's Avatar
    Member ID
    CZCC-4758
    Join Date
    Aug 2003
    Location
    Invercargill, New Zealand
    Posts
    635

    Default

    The guy claims they were bought for a now abandoned 260Z project, I assume nothing particularly relating to the triples but probably more the lack of finding cheap parts in NZ.

    You'll have to excuse the spelling etc, it's taken directly from his text.
    ---

    tripple s u's for datsun abandond project
    four 6 cylander L series. Has been done overseas. Manifold is allimuium. four carbs one for spare.



    To me the length of the 3,4 runners seem possibly long enough to cause issues but I have no idea when it comes down to it, anyone have anything to add?

    Obviously all the linkages will still have to be made etc. but if it goes for cheap enough it may be worth it. perhaps....
    -Michael

    1963 Prince Skyline S21D-4
    1973 Datsun 240K Hardtop KHGC110-002286
    1973 Datsun 240K Hardtop KHGC110-003345 (Parts Car) <- Now deceased

  6. #6
    philo "Z" opher Zedrally's Avatar
    Member ID
    CZCC-2363
    Join Date
    Jun 2002
    Location
    Australia
    Posts
    1,818

    Default

    Oh, ah, I've always had an interest in this type of set-up.
    If you don't want to go ahead with it let me know and we might be able to come to an arrangement on purchase of manifold.
    Mike of the Mire

    73 240Z Rally
    77 260Z Touring

    Bogged but not beaten

  7. #7
    Registered User Gee's Avatar
    Member ID
    CZCC-3136
    Join Date
    Nov 2002
    Location
    Melbourne / Gold Coast, Australia
    Posts
    392

    Default 3 x su

    I've got a mate who has 3 SU's on his 260 2+2. He loves 'em.. and it did make a difference on the amount of power the car had.
    I'd be looking on Jag sites to see if the "correct" way of doing it is to have 2 lefts and a right, or the other way 'round.

  8. #8
    philo "Z" opher Zedrally's Avatar
    Member ID
    CZCC-2363
    Join Date
    Jun 2002
    Location
    Australia
    Posts
    1,818

    Default

    Couldn't see the length of the inlet being a problem, good question about using the left or right, my guess is L R R.
    Mike of the Mire

    73 240Z Rally
    77 260Z Touring

    Bogged but not beaten

  9. #9
    Registered User
    Member ID
    CZCC-3196
    Join Date
    Dec 2002
    Location
    Vaxjo Sweden
    Posts
    3

    Default Triple S.U. carb.

    I`m interested in buying an intake manifold for triple SU carburators. I have a 240Z with L28 motor that I race with in Sweden. If anyone knows where I can get one,please contact me! My E-mail address is: tobbe54@swipnet.se
    Last edited by tobbe; 01-30-2005 at 12:32 AM.
    Tobbe

  10. #10
    Biafra for President e_racer1999's Avatar
    Member ID
    CZCC-6883
    Join Date
    Jun 2004
    Location
    San Diego
    Age
    38
    Posts
    2,171

    Default

    i heard somewhere (don't remember but i know it was a reliable source) that the triple SU setup was not very efficient, and the benefits over a twin SU system were miniscule. the reasoning was because of the setup of the standard I-6 engine. because the firing of the cylinders is set-up the way it is (i don't know the firing order off the top of my head) the usage of both of the twin SUs is equal and regular. when the third SU is thrown in there it offsets the system and causes irregularities throughout the entire intake system. basically you get uneven and irregular usage out of each of the carbs.
    Jason King
    6/72 240Z / HLS30 89646 (Yellow)
    1996 Infiniti I30 *I finally have all Nissans again!*
    1971 510 4door (wife's car)
    IZCC Member #14186

    Quote Originally Posted by xray View Post
    As unfortunate as it may be, if you want to vintage race, go Euro....If you want to race for real, stick with the Z!

  11. #11
    Registered User MikeW's Avatar
    Member ID
    CZCC-3294
    Join Date
    Dec 2002
    Location
    Atlanta, GA, USA
    Posts
    2,739

    Default

    Quote Originally Posted by e_racer1999
    i heard somewhere (don't remember but i know it was a reliable source) that the triple SU setup was not very efficient, and the benefits over a twin SU system were miniscule. the reasoning was because of the setup of the standard I-6 engine. because the firing of the cylinders is set-up the way it is (i don't know the firing order off the top of my head) the usage of both of the twin SUs is equal and regular. when the third SU is thrown in there it offsets the system and causes irregularities throughout the entire intake system. basically you get uneven and irregular usage out of each of the carbs.
    1-5-3-6-2-4

    Therefore, if the carbs were labeled A-B-C from the front of the car you'd have ACBCAB instead of the normal ABABAB. Each carb would be used once, have a one cylinder gap, be used again, and then have to wait for 3 cylinders.
    -Mike
    Add your Z to my online spreadsheet registry

  12. #12
    Registered User zed74's Avatar
    Member ID
    CZCC-7803
    Join Date
    Jan 2005
    Location
    Brisbane
    Age
    53
    Posts
    68

    Default

    We had 2 club members run the triple SU setup (with Aussie designed special run inlet manifold - only 12 or so made) & they were very good cars on both road & racetrack.
    I think a lot has to do with (a) inlet manifold design (b) camshaft specs etc.

  13. #13
    Biafra for President e_racer1999's Avatar
    Member ID
    CZCC-6883
    Join Date
    Jun 2004
    Location
    San Diego
    Age
    38
    Posts
    2,171

    Default

    Quote Originally Posted by MikeW
    1-5-3-6-2-4

    Therefore, if the carbs were labeled A-B-C from the front of the car you'd have ACBCAB instead of the normal ABABAB. Each carb would be used once, have a one cylinder gap, be used again, and then have to wait for 3 cylinders.
    the article was from zhome.com:
    http://zhome.com/ZCMnL/tech/TripleSUs.htm

    what the article states is that it causes "flow reversal" because of dead usage spots...... it's in the article...
    Last edited by e_racer1999; 01-29-2005 at 08:16 PM.
    Jason King
    6/72 240Z / HLS30 89646 (Yellow)
    1996 Infiniti I30 *I finally have all Nissans again!*
    1971 510 4door (wife's car)
    IZCC Member #14186

    Quote Originally Posted by xray View Post
    As unfortunate as it may be, if you want to vintage race, go Euro....If you want to race for real, stick with the Z!

  14. #14
    beandip beandip's Avatar
    Member ID
    CZCC-1887
    Join Date
    Mar 2002
    Location
    Beaverton, Oregon
    Age
    80
    Posts
    4,038

    Default

    1999 , good call , this is what I was going to say. Its all about the sequence and the interupted flow of the air mixture that deminishes the charging of the cylinders. Insted of the mixture continuing to move in a direction of the cylinders and there fore , to a degree , packs or compresses before the intake valve closes . It is interupted and stops ,then has to start again , thus loosing the ram effect. Tripple Mikunis or Webbers on the other hand amount to having one carb per cylinder , and with the correct stack can maintain the volicity of the mixture to the cylinder. They would look cool though.
    I'd rather die while I am living than live while I am dieing. CZC 1887 IZCC 12602 Member of NorthWest Z Car Club

  15. #15
    Dats a Nissan Enthusiast kyteler's Avatar
    Member ID
    CZCC-4758
    Join Date
    Aug 2003
    Location
    Invercargill, New Zealand
    Posts
    635

    Default

    I find it odd how people constantly regurgitate the info. shown on that website and yet, as people have mentioned, there ARE other Inline 6's that run triple SU's and some people even know other's personally that run them, it's a completely viable option. The GTR-XU1 Holden Torana's that ran them were not slow by any means.

    I have a manifold that I would be willing to sell but it needs to be tidied up, as it's put together pretty shabbily and both int. and exh. manifolds don't fit on together due to the int. manifold needing a little bit shaved off it in places.
    -Michael

    1963 Prince Skyline S21D-4
    1973 Datsun 240K Hardtop KHGC110-002286
    1973 Datsun 240K Hardtop KHGC110-003345 (Parts Car) <- Now deceased

  16. #16
    Forever Cleaning Alan Pugh's Avatar
    Member ID
    CZCC-1769
    Join Date
    Mar 2002
    Location
    Melbourne, Australia
    Age
    58
    Posts
    221

    Default

    Michael,

    I suppose the same old info is brought up all the time because it is accurate.

    I owned an LJ GTR XU1 and contrary to popular opinion they did not come out with triple SU's they were infact triple Stromberg 175 CD carbs.

    Yes the car was very fast new, and then I fitted a set of twin 2" SU's and got the full performance out of it. There was also some head, cam and exhaust work done but the twins do flow better.

    If you want to fit a set of triples, fit a set of triples, but if you ask advice be prepared to read the responses you get.

    Alan.

  17. #17
    Dats a Nissan Enthusiast kyteler's Avatar
    Member ID
    CZCC-4758
    Join Date
    Aug 2003
    Location
    Invercargill, New Zealand
    Posts
    635

    Default

    Alan,

    I have read the information before and I actually have a feeling either some of his thread is missing or perhaps it was also split into a series of threads. .. not sure.

    This thread was actually created last year and today when the man from Sweden posted it spawned the replies yet again.

    I understand that it may very well be accurate but by the sounds of most the responses in regards to this issue that I've read in several other places, they seem to essentially say "no, you cant do it because it doesn't flow right" and also certainly don't sound as though they're speaking from experience but more because they've read that website.

    I'm not interested in running triples myself any longer, I got that manifold that's mentioned above for bugger all but it requires work taht I can't be arsed completing in order to be fitted and then tuned ontop of that, so I just held my breath and waited for a twin setup to come about, and about 2 months ago I picked one up complete with an N42 L28 for $300NZD .. not too shabby

    Also, thanks for the clarification on the GTR-XU1, i guess that also goes to show you can't trust everything you've read or heard before, even if it isn't on the internet
    -Michael

    1963 Prince Skyline S21D-4
    1973 Datsun 240K Hardtop KHGC110-002286
    1973 Datsun 240K Hardtop KHGC110-003345 (Parts Car) <- Now deceased

  18. #18
    Forever Cleaning Alan Pugh's Avatar
    Member ID
    CZCC-1769
    Join Date
    Mar 2002
    Location
    Melbourne, Australia
    Age
    58
    Posts
    221

    Default

    Michael,

    I should have looked at the dates.

    I agree that saying it can't be done is wrong, it's more a why would you bother.

    I suppose the triple issue is never going to go away, next time maybe everyone should answer yeah there great do it. Then you'll get a new thread something like, I've fitted triple SU's and can't tell the differece, WHAT"S WRONG.

    Alan.

  19. #19
    beandip beandip's Avatar
    Member ID
    CZCC-1887
    Join Date
    Mar 2002
    Location
    Beaverton, Oregon
    Age
    80
    Posts
    4,038

    Default

    It is not the inline 6 it's the FIREING ORDER !!!!!! what works on another inline engine is of no reguard here . The tripples will work but the gain in minimal . I say go for it . Do it . but take the car to the dyno first then after the install and report back . They look good . run with out air cleaners and they sound good. Some people like the stainless buckets on the hondas too.
    I'd rather die while I am living than live while I am dieing. CZC 1887 IZCC 12602 Member of NorthWest Z Car Club

  20. #20
    Dats a Nissan Enthusiast kyteler's Avatar
    Member ID
    CZCC-4758
    Join Date
    Aug 2003
    Location
    Invercargill, New Zealand
    Posts
    635

    Default


    The firing order has been discussed before also.

    There's a thread here;
    http://www.classiczcars.com/forums/s...ight=triple+SU

    and another one or two floating around.

    I fail to understand how another inline six that runs the same firing order (the 153624 that MOST inline sixes run) would be of no regard.

    Nevermind, this is a waste of time.
    -Michael

    1963 Prince Skyline S21D-4
    1973 Datsun 240K Hardtop KHGC110-002286
    1973 Datsun 240K Hardtop KHGC110-003345 (Parts Car) <- Now deceased

  21. #21
    Instant Human, ADD Coffee Z Kid's Avatar
    Member ID
    CZCC-2623
    Join Date
    Aug 2002
    Location
    Gawler SA
    Posts
    747

    Default

    Just while you are on the topic of firing order, I would love for you to suggest a firing order that provides the required balance that doesnt end up with the same pattern as the L series/XKE engines in terms of carbs used/timing of firing. I have been thinking and thinking, and no matter what combination you use to get it to fire, in order for it to be balanced it has to have the same sort of ratio or carbs to cylinders and firing times. Incidentally triple SU's have an advantage over the webbers on other cars in terms of drivability because due to the venture style and lack of a pump type setup within the carb, when you put your foot down you cant really flood the engine unlike the webbers which can create a lot of popping and farting. I think well done with equal length manifold runners it could be a great conversion, and they really are a very simple carb to tune.
    I can only please one person per day,
    Today is Not your day,
    And tomorrow is not looking good either.

  22. #22
    Biafra for President e_racer1999's Avatar
    Member ID
    CZCC-6883
    Join Date
    Jun 2004
    Location
    San Diego
    Age
    38
    Posts
    2,171

    Default

    why don't we just do 6 SUs and call it a day!
    Jason King
    6/72 240Z / HLS30 89646 (Yellow)
    1996 Infiniti I30 *I finally have all Nissans again!*
    1971 510 4door (wife's car)
    IZCC Member #14186

    Quote Originally Posted by xray View Post
    As unfortunate as it may be, if you want to vintage race, go Euro....If you want to race for real, stick with the Z!

  23. #23
    HS30-00352, HS30-101370 240znz's Avatar
    Member ID
    CZCC-1608
    Join Date
    Jan 2002
    Location
    New Zealand
    Age
    51
    Posts
    984

    Default What about individual motorcycle carbs

    Not such a silly question considering that individual flat slide mukuni's are used on motorcycle engines with great results. I wonder if it has been done on a L series engine? But what a massive PITA to set up, just imagine the linkages....OMG

    But as Michael says, he has twin SU's now, so he'll just use them and to hell with the exercise and self emptying of wallet.
    Zed not Zee

    HS30-00352 still being rebuilt (year 6)
    HS30-101370 chopped in half

    CZCC #1608

  24. #24
    Biafra for President e_racer1999's Avatar
    Member ID
    CZCC-6883
    Join Date
    Jun 2004
    Location
    San Diego
    Age
    38
    Posts
    2,171

    Default

    i've heard (from here or hybridz maybe?) of somebody doing that but with bad results...... from what i've heard they wont idle under 3000 w/o popping and stuff......... anyway, i've been considering doing some research on that and thinking it would be cool as heck!

    anyway, i'm sure someone will let us know....
    Jason King
    6/72 240Z / HLS30 89646 (Yellow)
    1996 Infiniti I30 *I finally have all Nissans again!*
    1971 510 4door (wife's car)
    IZCC Member #14186

    Quote Originally Posted by xray View Post
    As unfortunate as it may be, if you want to vintage race, go Euro....If you want to race for real, stick with the Z!

  25. #25

    Default previous thread

    to my recollection there was a thread like 6 months ago on this site about 6 carbs on the z and someone who had done it and there were pictures of it on this site anyone else remember that?
    Willing to learn what the masters of Z-ology teach me... just cram it in my brain

  26. #26
    Registered User
    Member ID
    CZCC-3196
    Join Date
    Dec 2002
    Location
    Vaxjo Sweden
    Posts
    3

    Default

    TO KYTELER
    If you are interrested to sell the intakes to me, please mail me so we can discuss the price and shipping arrangements. If you also have a SU carburator model HS 8, 2", I`m interrested in buying that too. My plan is to build a plenum on the intakes, I think it might work.
    Tobbe
    240Z -73 L28 Built only for roadracing. The class I`m racing only permitts one single carb./two cylinders maximum. Otherwise I should use triple Webers.
    Last edited by tobbe; 02-03-2005 at 12:41 PM.
    Tobbe

  27. #27
    Registered User 240ZX's Avatar
    Member ID
    CZCC-1420
    Join Date
    Dec 2001
    Location
    Santa Paula, California
    Age
    67
    Posts
    1,884

    Default

    Quote Originally Posted by 240znz
    Not such a silly question considering that individual flat slide mukuni's are used on motorcycle engines with great results. I wonder if it has been done on a L series engine? But what a massive PITA to set up, just imagine the linkages....OMG

    But as Michael says, he has twin SU's now, so he'll just use them and to hell with the exercise and self emptying of wallet.
    240znz, I think the multi Mukuni carb setup would likely work very well, as by theory many small ventri's are better than a few large ones, equating to better overall responce. Regarding the throttle linkage, it wouldn't be that big of a chore to build and install. Building the manifolds would be another issue, but again not that big of a chore. Would that look very cool or what? I quess the question would be....could one find Mukuni's appropreately sized for the job. Tuning and syncing the Mukuni's would be the same as on the motorcycle engines with the exception of 6 carb instead of usual 4 carbs. Is someone out there getting excited enough to take that trip?

  28. #28
    Biafra for President e_racer1999's Avatar
    Member ID
    CZCC-6883
    Join Date
    Jun 2004
    Location
    San Diego
    Age
    38
    Posts
    2,171

    Default

    ^^ i wish i had the time/money to do something like that and actually make it work....
    Jason King
    6/72 240Z / HLS30 89646 (Yellow)
    1996 Infiniti I30 *I finally have all Nissans again!*
    1971 510 4door (wife's car)
    IZCC Member #14186

    Quote Originally Posted by xray View Post
    As unfortunate as it may be, if you want to vintage race, go Euro....If you want to race for real, stick with the Z!

  29. #29
    Registered User
    Member ID
    CZCC-8677
    Join Date
    Jul 2005
    Location
    dayton nv,
    Age
    85
    Posts
    1

    Default

    I need information on how to overhaul and set up my su carbs on a 240z

  30. #30
    Biafra for President e_racer1999's Avatar
    Member ID
    CZCC-6883
    Join Date
    Jun 2004
    Location
    San Diego
    Age
    38
    Posts
    2,171

    Default

    ztherapy.com

    i recommend you invest in the Just SUs vid. excellent!
    Jason King
    6/72 240Z / HLS30 89646 (Yellow)
    1996 Infiniti I30 *I finally have all Nissans again!*
    1971 510 4door (wife's car)
    IZCC Member #14186

    Quote Originally Posted by xray View Post
    As unfortunate as it may be, if you want to vintage race, go Euro....If you want to race for real, stick with the Z!

  31. #31
    beandip beandip's Avatar
    Member ID
    CZCC-1887
    Join Date
    Mar 2002
    Location
    Beaverton, Oregon
    Age
    80
    Posts
    4,038

    Default SUs

    Quote Originally Posted by ****
    I need information on how to overhaul and set up my su carbs on a 240z
    The best advise I can give you for overhauling the SUs is to go to Ztherapy and get the vedio on this . To adjust them go to the tec articles and pull up adjusting SUs . Gary
    I'd rather die while I am living than live while I am dieing. CZC 1887 IZCC 12602 Member of NorthWest Z Car Club

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Bookmarks

Bookmarks

Posting Permissions

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