Results 1 to 33 of 33

Thread: Triple Carbs vs. SU

  1. #1
    Registered User kcoke's Avatar
    Member ID
    CZCC-12810
    Join Date
    Oct 2006
    Location
    Redding, California
    Posts
    89

    Default Triple Carbs vs. SU

    What would be better for my L24? I Have a racing performance Cam with MSA 3 into 2 headers and electronic ignition. What would be better for my engine SU carbs or a set of triple carbs? Or even a 4 barrel conversion or the dual webers? I want to make my engine fast. Its a 1971 Datsun 240z. My goal is to smoke the stock GT's around.

  2. #2
    Registered User
    Member ID
    CZCC-5121
    Join Date
    Oct 2003
    Location
    Seattle, WA
    Posts
    2,362

    Default

    Anyone else get deja vu reading this???
    Jon

  3. #3
    Registered User Surfsup's Avatar
    Member ID
    CZCC-13926
    Join Date
    Feb 2007
    Location
    So Cal
    Age
    35
    Posts
    214

    Default

    Quote Originally Posted by jmortensen View Post
    Anyone else get deja vu reading this???
    yeah. haha.. go search man just type it up.

    haha like just do it from nike AHHAHA

  4. #4
    Biafra for President e_racer1999's Avatar
    Member ID
    CZCC-6883
    Join Date
    Jun 2004
    Location
    San Diego
    Age
    39
    Posts
    2,171

    Default

    best bet's either the SUs or the triples.

    but ya, search and you'll get A LOT more info....
    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!

  5. #5
    Registered User
    Member ID
    CZCC-10748
    Join Date
    Feb 2006
    Location
    Hillsboro, Oregon
    Age
    75
    Posts
    47

    Default

    kcoke,

    You will find more info than you'll know what do with by using the search function, both here and on other sites. If your Z has the four-speed, you probably have the 3.36 geared R180 differential. Installing a 3.90 or 4.11 differential will dramatically affect your acceleration, probably much more than carburetor choice. A five-speed will still provide good economy.

    Having said that, There are many 240Z drivers running mid 13's to high 12's with well-tuned SU's. Most use the 2.8 liter block bored and stroked, but there are several running just the 2.8 liter block. Almost all have done some serious head work in addition to cam, ignition, headers, and proper gearing.

    I've seen, and read about, some very hot Z's running just the 2.4 block. And if you really love triples as I do, then go for it. They will usually improve your low-end torque and add horsepower over SU's. With your 2.4 block, I would stick with 40's, rather than 44 or 45's. But be prepared for jet swapping and dyno tuning to get them properly set up and to get the most out of your triples. This will not be cheap. Once you hear the sound of triples and experience the performance, you'll be hooked as I am.

    As for dual Weber DGV's, they were originally used on the 73 240's and 74 260's to replace the poor performance-designed flat top low emission carburetors. But once used round top SU's became available, many ditched the DGV's in favor of the earlier round top SU's. The DGV's are more complicated than the SU's, but they can be made to run well.

    All of the above are my opinions, and their are many, many more knowledgeable folks on this site. Some of them will chime in to correct or add to what I've said. But do yourself a favor and do the search, too. Good luck and best wishes in reaching your performance goals.
    Roger

    09/70 1971 series 1 (under modified restoration)
    12/70 1971 series 1 (under restoration)
    07/72 1972 nice driver
    11/72 1972 parts car

  6. #6
    Age really means nothing! agemeansnothing's Avatar
    Member ID
    CZCC-8820
    Join Date
    Jul 2005
    Location
    Nm
    Age
    27
    Posts
    351

    Default

    It kind of depends on what the elevation is where your living though.

  7. #7
    Biafra for President e_racer1999's Avatar
    Member ID
    CZCC-6883
    Join Date
    Jun 2004
    Location
    San Diego
    Age
    39
    Posts
    2,171

    Default

    just bite the bullet and go turbo!
    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!

  8. #8
    Registered User
    Member ID
    CZCC-2139
    Join Date
    May 2002
    Location
    Salem Or
    Posts
    1,556

    Default Not to muddy the water,

    but how about a set or triple SUs? We are doing the development (say casting of manifolds) work to duplicate the triple set-up Steve Epperly had on the ZTherapy Z. We can guaranty the pleasure of driving on SUs, with the punch of three of 'em, with the simplicity of playing with mixture nuts & three screws to get 'em right, while being so subtle the average car guy wont know the difference.
    Bruce Palmer
    Salem Or
    Sales@ztherapy.com
    www.ztherapy.com
    503-587-9800

  9. #9
    Registered User madkaw's Avatar
    Member ID
    CZCC-7622
    Join Date
    Dec 2004
    Location
    bloomington IN
    Age
    58
    Posts
    2,288

    Default

    We are all waiting Bruce-bring it on, I'm ready!!!
    Steve
    71 240z,bw-5sp 2.4-40 over,balanced,e-88,big valves,ported&polished, stage2,header, triple Mikuni's 40's
    3.90 Subaru STI LSD

  10. #10
    Registered User
    Member ID
    CZCC-1316
    Join Date
    Oct 2001
    Location
    somewhere
    Posts
    2,495

    Thumbs up

    Quote Originally Posted by Bruce Palmer View Post
    but how about a set or triple SUs? We are doing the development (say casting of manifolds) work to duplicate the triple set-up Steve Epperly had on the ZTherapy Z. We can guaranty the pleasure of driving on SUs, with the punch of three of 'em, with the simplicity of playing with mixture nuts & three screws to get 'em right, while being so subtle the average car guy wont know the difference.
    Sounds good I saw some videos on YouTube.com of Mike's yellow 240z with triple SU's manifold it looked awesome. Is that your work?

  11. #11
    Registered User
    Member ID
    CZCC-2139
    Join Date
    May 2002
    Location
    Salem Or
    Posts
    1,556

    Default That is the very same set-up....

    ... that Steve built as the proto-type. Bolted them on did the tweaking and they have run like a swiss watch ever since ON BOTH CARS. They were put on Mike's car to get it up and running and for the show, but they will now be used for casting pattern work.

    How many of you here think you would be interested in this lash-up complete ready to bolt on tweak 'em and go??
    Bruce Palmer
    Salem Or
    Sales@ztherapy.com
    www.ztherapy.com
    503-587-9800

  12. #12
    Supporting Member ChrisA's Avatar
    Member ID
    CZCC-5906
    Join Date
    Feb 2004
    Location
    Lincoln, NE
    Age
    53
    Posts
    1,471

    Default

    Quote Originally Posted by Bruce Palmer View Post
    ... How many of you here think you would be interested in this lash-up complete ready to bolt on tweak 'em and go??

    Hi Bruce, you can mark me down for a complete setup.

    Would you need my SU's back? They were done by Scott B. a few years ago, and I have two that need overhauled as well.


    Seriously interested,

    Chris A.
    1973 240Z HLS30-156693

  13. #13
    Registered User
    Member ID
    CZCC-2139
    Join Date
    May 2002
    Location
    Salem Or
    Posts
    1,556

    Default Looks like time to start a "triple list"

    Chris,
    Either call me at 503-587-9800 or email me at sales@ztherapy.com and we can go over your questions. I'd say that someone out there might benefit from those early ZTherapy carbs more than we would by dissasembling them for core parts. They are not quite up to the standards of our current production but should still have a lot of useable life left. Anyway Ebay or ??? might be the way to go when the time comes.
    Bruce Palmer
    Salem Or
    Sales@ztherapy.com
    www.ztherapy.com
    503-587-9800

  14. #14
    Known Zitus carrier! hls30.com's Avatar
    Member ID
    CZCC-4106
    Join Date
    May 2003
    Location
    Savannah, Georgia
    Posts
    6,702

    Default

    Quote Originally Posted by Bruce Palmer View Post
    but how about a set or triple SUs? We are doing the development (say casting of manifolds) work to duplicate the triple set-up Steve Epperly had on the ZTherapy Z. We can guaranty the pleasure of driving on SUs, with the punch of three of 'em, with the simplicity of playing with mixture nuts & three screws to get 'em right, while being so subtle the average car guy wont know the difference.
    I could be persuaded...
    Will
    A Z is beautiful from any angle, I just happen to prefer to view from the drivers' seat!

  15. #15
    Semi-retired admin Arne's Avatar
    Member ID
    CZCC-8596
    Join Date
    Jun 2005
    Location
    Eugene, Oregon, USA
    Age
    63
    Posts
    8,465

    Default

    IF I were to finish my yellow car, and if that finished product included an L28 rather than the L24 I have in it now, I think triple SUs would be extremely cool. I don't think that'll happen - but I can't rule it out...
    Arne - Former owner, HLS30-37705, 7/71, 905 Red
    Car blogs - 240Z - Porsche 911

  16. #16
    Supporting Member ChrisA's Avatar
    Member ID
    CZCC-5906
    Join Date
    Feb 2004
    Location
    Lincoln, NE
    Age
    53
    Posts
    1,471

    Default

    Quote Originally Posted by Bruce Palmer View Post
    those early ZTherapy carbs...SNIP....are not quite up to the standards of our current production

    OUCH!!!!! That stung a little considering what I spent on them.

    Okay, Bruce, when the time is right for me I'll call you about getting triples.

    Chris A.
    1973 240Z HLS30-156693

  17. #17
    Admin Mike's Avatar
    Member ID
    CZCC-4
    Join Date
    Feb 2000
    Location
    Seattle, WA
    Age
    50
    Posts
    6,070

    Default

    I'm interested.
    Mike

  18. #18
    Age really means nothing! agemeansnothing's Avatar
    Member ID
    CZCC-8820
    Join Date
    Jul 2005
    Location
    Nm
    Age
    27
    Posts
    351

    Default

    Ya I'd like to know more about them.

  19. #19
    Registered User
    Member ID
    CZCC-2139
    Join Date
    May 2002
    Location
    Salem Or
    Posts
    1,556

    Default

    Quote Originally Posted by ChrisA View Post
    OUCH!!!!! That stung a little considering what I spent on them.

    Okay, Bruce, when the time is right for me I'll call you about getting triples.

    Chris A.
    Chris, Just saying that the product out the door since Steve took over how the carbs are done has resulted in a better carb. Not that Scott necessarily built a bad carb the QC was up and down. If yours are working fine you musta got an UP set and that's good.

    Steve, by the way, fixed all the Scott's "others" under warranty gratis for the duration of the warranty periods just so you all know where he is coming from customer care wise.
    Bruce Palmer
    Salem Or
    Sales@ztherapy.com
    www.ztherapy.com
    503-587-9800

  20. #20
    Registered User
    Member ID
    CZCC-1316
    Join Date
    Oct 2001
    Location
    somewhere
    Posts
    2,495

    Default Triple SU's.

    Quote Originally Posted by Bruce Palmer View Post
    ... that Steve built as the proto-type. Bolted them on did the tweaking and they have run like a swiss watch ever since ON BOTH CARS. They were put on Mike's car to get it up and running and for the show, but they will now be used for casting pattern work.

    How many of you here think you would be interested in this lash-up complete ready to bolt on tweak 'em and go??
    They seem like a very cool set up, however I have bought myself a set of Triple 44 Mikuni's already. I have 4 SU carbs here also, so I could easily set this up with just a manifold. Given I'm in Australia and shipping all items and the extra expense of conversion from US to AU it probably wouldn't be worthwhile for me.

    I'd consider buying a manifold just for the ultra cool triple SU look. It looks nice and standard but offers that bit extra.

    Have you got anything to compare Triple SU's with Triple Mikuni's? Any pro's con's?

    So at this stage I'm not interested, however I'd be interested in a Triple SU's manifold and possibly linkage set.

  21. #21
    Registered User toecutter's Avatar
    Member ID
    CZCC-3694
    Join Date
    Mar 2003
    Location
    melbourne
    Age
    48
    Posts
    297

    Default

    my guess is you could sell quite a few of tripple SU manifolds if somebody made them up. It would be interesting to get some feedback on any performance gains!? they certainly would look pretty cool though, i would be up for one manifold!

  22. #22
    Biafra for President e_racer1999's Avatar
    Member ID
    CZCC-6883
    Join Date
    Jun 2004
    Location
    San Diego
    Age
    39
    Posts
    2,171

    Default

    what about the issue of the sharing of the carbies? i know that webers/mikunis don't have that problem because there is one barrel per cylinder, but IIRC there was some controversy over the firing order and the separation of the SUs.... not trying to start an argument, it's just that i have always bypassed triple SUs because of that "issue"
    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
    Registered User
    Member ID
    CZCC-5121
    Join Date
    Oct 2003
    Location
    Seattle, WA
    Posts
    2,362

    Default

    Quote Originally Posted by e_racer1999 View Post
    what about the issue of the sharing of the carbies? i know that webers/mikunis don't have that problem because there is one barrel per cylinder, but IIRC there was some controversy over the firing order and the separation of the SUs.... not trying to start an argument, it's just that i have always bypassed triple SUs because of that "issue"
    Just because something isn't perfect doesn't mean it won't work. Yes there is a firing order issue. But Jags, Austin Healeys and I think Triumphs all ran triple SU's on a 6 cylinder from the factory.

    I for one would be interested in seeing a back to back comparison of dual to triple SUs to Mikunis or Webers. Especially if you were using Cary's old engine. That would really be applicable to my own situation. I expect that the Mikunis would come out on top, but I would be happily surprised if they didn't.
    Jon

  24. #24
    Semi-retired admin Arne's Avatar
    Member ID
    CZCC-8596
    Join Date
    Jun 2005
    Location
    Eugene, Oregon, USA
    Age
    63
    Posts
    8,465

    Default

    Quote Originally Posted by jmortensen View Post
    I for one would be interested in seeing a back to back comparison of dual to triple SUs to Mikunis or Webers. Especially if you were using Cary's old engine. That would really be applicable to my own situation. I expect that the Mikunis would come out on top, but I would be happily surprised if they didn't.
    And even if the Mikunis did come out on top, it wouldn't surprise me at all if the difference was rather small.
    Arne - Former owner, HLS30-37705, 7/71, 905 Red
    Car blogs - 240Z - Porsche 911

  25. #25
    Supporting Member ChrisA's Avatar
    Member ID
    CZCC-5906
    Join Date
    Feb 2004
    Location
    Lincoln, NE
    Age
    53
    Posts
    1,471

    Default

    Quote Originally Posted by Bruce Palmer View Post
    Chris, Just saying that the product out the door since Steve took over how the carbs are done has resulted in a better carb. Not that Scott necessarily built a bad carb the QC was up and down. If yours are working fine you musta got an UP set and that's good.

    Steve, by the way, fixed all the Scott's "others" under warranty gratis for the duration of the warranty periods just so you all know where he is coming from customer care wise.
    Thanks Bruce, I must have got an UP set then. So I'm not upset!



    Quote Originally Posted by jmortensen
    Just because something isn't perfect doesn't mean it won't work. Yes there is a firing order issue. But Jags, Austin Healeys and I think Triumphs all ran triple SU's on a 6 cylinder from the factory.
    Yep, my brother-in-law's Healey runs like a scalded dog. Big 6 with triple's stock.

    Chris A.
    1973 240Z HLS30-156693

  26. #26
    Biafra for President e_racer1999's Avatar
    Member ID
    CZCC-6883
    Join Date
    Jun 2004
    Location
    San Diego
    Age
    39
    Posts
    2,171

    Default

    that would be a great comparison.... GET TO IT!!!!
    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!

  27. #27
    Known Zitus carrier! hls30.com's Avatar
    Member ID
    CZCC-4106
    Join Date
    May 2003
    Location
    Savannah, Georgia
    Posts
    6,702

    Default

    Quote Originally Posted by jmortensen View Post
    ...
    I for one would be interested in seeing a back to back comparison of dual to triple SUs to Mikunis or Webers. Especially if you were using Cary's old engine. That would really be applicable to my own situation. I expect that the Mikunis would come out on top, but I would be happily surprised if they didn't.
    It looks like my car will be getting its stock L24 for Daytona-I have planned to rebuild and use my set of tripple 40 dcoe 18s for it. I have a local Dyno, and changing out a maniflold and linkage isn't that labor intensive...still a ways off though.
    Will
    A Z is beautiful from any angle, I just happen to prefer to view from the drivers' seat!

  28. #28
    Do it in a Z Mat M's Avatar
    Member ID
    CZCC-6791
    Join Date
    Jun 2004
    Location
    Sierra Foothills outside of SACRAMENTO, CA
    Posts
    545

    Default

    congratulations on a successful hijack!!!

    I would be interested in a complete triple SU setup!! I would also like to know what kind of performance comparisons you would be able to test with your resources, as well as the outcomes!
    Mat
    AKA MatMan
    MatM@M2Differentials.com

    m2differentials.com


    01/71 HLS30-19724 original 918, 4 speed, ready for the 5 spd swap, and R200 diff from the '81ZX
    08/71 HLS30-41979 multicolored auto, but under the knife - SOLD!!
    81 ZX Grey/blue 5-speed donor car, runs! - SOLD!!
    82 ZX Black auto T-top - motor/3.90 R200 donor car - MOST excellent PAPER WASP condo. - SOLD!!

  29. #29
    Registered User deadflo's Avatar
    Member ID
    CZCC-5999
    Join Date
    Feb 2004
    Location
    spokane
    Posts
    485

    Default

    Besides the debate about how good the triple set up works with a inline six, what about how the triple Su setup would work with a stock engine? we have heard here before the triple set up doesn't add much without internal tweaking.
    Although they would look totally cool.(They remind of me of early XKE's.)

  30. #30
    Crumudgeon
    Member ID
    CZCC-798
    Join Date
    Apr 2000
    Location
    La Habra, CA USA
    Age
    60
    Posts
    1,374

    Default

    I'm one of the skeptics based on some testing I saw years ago. Javier at JG Engine Dynamics built a triple SU manifold and put 6 EGT sensors in the exhaust header. On the dyno it was pretty obvious that cylinders 1, 2, 5, and 6 were running lean above 5,000 rpm compared to 3 and 4. Changing the needles on the first and third SU helped at high rpm but those cylinders ended up being rich under load at lower rpms. The issue appeared to be reversion in the intake manifold on those 4 cylinders and a strobe light shown on the first and third SUs actually showed pulses of the air/fuel mixture standing out of the carb throats until the engine went past about 5,000 rpm. Even then, the piston could be seen pulsing up and down with the strobe light on one and three while the piston on SU number two was rock steady.

    Looking at the firing order and cylinder pairing shows why there would be reversion in the first and third SU.

    Firing Order, Degree of Rotation
    1 ----------- 0
    5 ----------- 120
    3 ----------- 240
    6 ----------- 360
    2 ----------- 480
    4 ----------- 600
    1 ----------- 720 (0)
    5 ----------- 840 (120)
    3 ----------- 960 (240)
    6 ----------- 1080 (360)
    2 ----------- 1200 (480)
    4 ----------- 1320 (600)
    1 ----------- 1440 (720)

    3-4 Intake charge every 360deg
    1-2 Intake charge 480 deg, then 240deg
    5-6 Intake charge 240 deg, then 480deg
    I'm not saying that this won't work and it probably will feel great on a street car. But if you're trying to extract the last bit of power you'll have some mixture issues to work through.

  31. #31
    Registered User tbird481's Avatar
    Member ID
    CZCC-14233
    Join Date
    Apr 2007
    Location
    New Hampshire
    Age
    60
    Posts
    6

    Default

    Wow! Perfect timing for this thread...I'm in the middle of body restoration, motor rebuild was a couple years back and I've been looking for carb options. Running the original L24 with a Rebello E-31 head setup for ITS (and need to back off the cam for streetability), a set of MSA headers.

    If there's a list for the triple-SU manifold, please add me!

    Mark
    HLS30-19137 1/71 Series1

  32. #32
    Registered User
    Member ID
    CZCC-5121
    Join Date
    Oct 2003
    Location
    Seattle, WA
    Posts
    2,362

    Default

    Quote Originally Posted by tbird481 View Post
    Wow! Perfect timing for this thread...I'm in the middle of body restoration, motor rebuild was a couple years back and I've been looking for carb options. Running the original L24 with a Rebello E-31 head setup for ITS (and need to back off the cam for streetability), a set of MSA headers.

    If there's a list for the triple-SU manifold, please add me!
    You're running ITS and you were looking at a cam and now considering triple SU's? In the middle of a body restoration???
    Jon

  33. #33
    Registered User tbird481's Avatar
    Member ID
    CZCC-14233
    Join Date
    Apr 2007
    Location
    New Hampshire
    Age
    60
    Posts
    6

    Default

    Never ran ITS, was on a path to but changed my mind (and moved)...
    HLS30-19137 Series 1 built 1/71

Thread Information

Users Browsing this Thread

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

Similar Threads

  1. SU Carbs different and not running good
    By neoxman in forum SU Carb Discussions
    Replies: 19
    Last Post: 09-29-2006, 05:28 PM
  2. SU carbs with metal oil filler caps?
    By zcarnut in forum Carburetors (S30)
    Replies: 14
    Last Post: 07-11-2006, 02:48 PM
  3. Stromberg 175 CD-2 SE vs. SU Carbs?
    By Sidedraft260 in forum Carburetors (S30)
    Replies: 13
    Last Post: 03-18-2005, 05:37 AM
  4. SU carbs and high revs
    By 240ZMan in forum Carburetors (S30)
    Replies: 40
    Last Post: 10-06-2003, 07:29 AM
  5. Triple Webers or Dual SUs?
    By Chino 240Z in forum Carburetors (S30)
    Replies: 15
    Last Post: 07-31-2003, 01:17 AM

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
  •