THINK OUTSIDE THE BOX 710 Posted January 28, 2009 Report Share Posted January 28, 2009 I have a set sss su's and new weber 38dgev for a L20b with a 280zx 5 speed but don't know what to use. Any opinions on what wolud better all around: reliability,maintenance,tunning,power,gas consumption. thanks. Quote Link to comment
freaky510 Posted January 28, 2009 Report Share Posted January 28, 2009 dgev will need less tunning.the s/u you will tune at least once a month.At least the set i got need it lol Quote Link to comment
banzai510(hainz) Posted January 28, 2009 Report Share Posted January 28, 2009 why dont you do both and tell us the results!!!!!!!! SU are OLD DGV is NEW Best to port out the intake manifold if using the 38DGV to mack full use as the SU manifolds are 1.5 inch runners Quote Link to comment
HRH Posted January 28, 2009 Report Share Posted January 28, 2009 SUs tend to be better on gas than a synchronous 38/38. I've run both, I prefer the SU carbs as they seem to be less prone to detonation issues. And they're damn simple. Tuning is more annoying since you're balancing two carbs, wherease the DG is only one. However, if you have other issues, the DG 38/38 is one of the worst for pinpointing problems. I'm assuming your motor is all well and good though. Just make sure your intake manifold size matches your head port size. Goes without saying, but some people in the past have put a Cannon intake manifold on an L head without port matching, and that makes a real nightware. (No no, not me! I wouldn't have done that!) :) You can go small into big, but not big into small. Quote Link to comment
hang_510 Posted January 28, 2009 Report Share Posted January 28, 2009 why dont you do both and tell us the results!!!!!!!! SU are OLD DGV is NEW my $0.02 = DGV (new is good too) only because i know so little about SU's Quote Link to comment
racerx Posted January 28, 2009 Report Share Posted January 28, 2009 weber 38/38 is easy to adjust, not sure about SU condition. Quote Link to comment
slodat Posted January 29, 2009 Report Share Posted January 29, 2009 SU's all the way. No questions asked. They are the best "driving" carb I've had on any car, ever. Make sure they are in good shape. If not, send them to Z Therapy and have them go through them. Quote Link to comment
Guest jaimesix Posted January 29, 2009 Report Share Posted January 29, 2009 I am installing a Weber 38 DGES syncroneous in my L20Bed datsun 610 with 5 speed gear box. The 38 is a syncroneos "DGES" ...( not a DGEV, DGEV stands for the progressive 32/36 Weber in which one throat, the 32 one opens first, the 36 throat opens at higher RPM. The DGES is syncroneous, both throats work from a start )... is a very easy to adjust and work on carburetor. While I do not rest any performance out from the SUs, if you are not familiar with its configuration, or if the S/Us are not new or rebuilt, I would stick to the 38 DGES. You can play with jets and emulsion tubes within the Weber 38, the S/U will be difficult to modify unless you know how to deal with them. Both are good, but the simplest approach is the Weber 38DGES. Jaime.____________________________________________________ Quote Link to comment
THINK OUTSIDE THE BOX 710 Posted January 29, 2009 Author Report Share Posted January 29, 2009 Thanks guy's for the opinions looks like the weber would be te better choice the su's that i have are in ok condition but the weber is new and new k&n filter got it for FREE!. Anybody know witch one would have more power? thanks again. Quote Link to comment
HRH Posted January 29, 2009 Report Share Posted January 29, 2009 They're probably about equal for power potential. While constant velocity carbs like SUs will not be as good on the top end as a side draft weber due to the way the carb is configured, you have a downdraft, which means your air/fuel mixture has to bend 90 degrees before it enters the intake, which kills flow. Quote Link to comment
ggzilla Posted January 29, 2009 Report Share Posted January 29, 2009 Forget the SUs, and try to find genuine factory twin Hitachi sidedrafts. Smoother, more responsive and better fuel economy than the Weber downdraft. The weber is bigger. Quote Link to comment
HRH Posted January 29, 2009 Report Share Posted January 29, 2009 The Hitachi SUs are the same as British SUs, though their overall quality might be a little better. I'd say for using what he has, I'd go SUs. I'm with slodat on this, the driveability is hands down better than the Weber 38/38. Did I mention they look cooler? :) Quote Link to comment
ggzilla Posted January 29, 2009 Report Share Posted January 29, 2009 (edited) How do you mean "the same"? I have seen both, they are definitely different, though quite similar. Do you mean performance and tuning are nearly identical? Or do you mean all the parts interchange? I have two pair Hitachi's: 510 SSS pair, and Datsun 1200 GX pair. The 710 SSS type I'm pretty sure is quite different (4-bolt flanges, flat-tops, etc). I have a four-bolt manifold, but no matching carbs for it. Edited January 29, 2009 by ggzilla Quote Link to comment
HRH Posted January 29, 2009 Report Share Posted January 29, 2009 Sorry, I meant same as in they are the same design, just the Hitachis are what Japan copied from Britain, and apparently the Hitachis are a little better machined, from what I've been told, but I haven't run a set of Hitachi SUs. I don't know if the needles and other stuff are interchangeable between British or Japanese. Clearly the bell is matched to the carb, not interchangeable. Quote Link to comment
ppeters914 Posted January 29, 2009 Report Share Posted January 29, 2009 My understanding from the guru's is that almost nothing is interchangeable between the British SU's and Japanese Hitachi's other than the jets. Trivia fact: SU were named for Skinners Union, the company that produced them. Quote Link to comment
ppeters914 Posted January 29, 2009 Report Share Posted January 29, 2009 I asked a similar question on the Bluebirds mailing list, i.e. keep the Weber 32/36 or switch to SU's on my L20b. It was nearly unanimous: the Weber is a great carb, but the SU's are better for mileage and performance. Once dialed in, you rarely touch 'em outside of checking/changing the damper oil. My decision? Get it running and on the road with the Weber until I have the W53 head, L16/L18 exhaust, and SSS 38mm SU's ready to install. I don't know if the needles and other stuff are interchangeable between British or Japanese. Clearly the bell is matched to the carb, not interchangeable. My understanding from the guru's is that almost nothing is interchangeable between the British SU's and Japanese Hitachi's other than the jets. Trivia fact: SU were named for Skinners Union, the company that produced them. Quote Link to comment
DISLEXICDIME Posted January 29, 2009 Report Share Posted January 29, 2009 dont forget you need a wide band to tune su's right. if you dont have one you are just guessing. it can be dun it just takes for ever Quote Link to comment
ppeters914 Posted January 29, 2009 Report Share Posted January 29, 2009 dont forget you need a wide band to tune su's right. if you dont have one you are just guessing. it can be dun it just takes for ever ...and a wide band is....??? Quote Link to comment
DISLEXICDIME Posted January 30, 2009 Report Share Posted January 30, 2009 here is an example http://zeitronix.com/ Quote Link to comment
ggzilla Posted January 30, 2009 Report Share Posted January 30, 2009 And before they invented wideband oxygen sensor... race teams were just guessing? Hitachis need tuning just like Weber needs tuning. There are several ways to do it, an O2 sensor is one way. Quote Link to comment
Jason Posted January 30, 2009 Report Share Posted January 30, 2009 I think any carburettor needs tuning, I do it by the "colour" of the spark plugs and if the engine detonates on me at a given degree of advance. I like the Hitachi built SU's for the look and sound. For twin carbs they are pretty easy to work with for balancing if you've got a Unisyn. Pretty fun to mess around with too. I managed to pass smog with mine with a .507 lift cam on the first try this year too! Quote Link to comment
THINK OUTSIDE THE BOX 710 Posted January 30, 2009 Author Report Share Posted January 30, 2009 Well it looks like it goes down to what you like i had su's they worked great but they were rebuilt by z therapy had no problems and like HRH said they look coooool!!!. I had in the past 32/36 weber i like them to but never a 38/38 see what happens. Quote Link to comment
DISLEXICDIME Posted January 30, 2009 Report Share Posted January 30, 2009 ggzilla if you read my post dont forget you need a wide band to tune su's right. if you dont have one you are just guessing. it can be dun it just takes for ever it says it can be dun I tuned slodats car city hunter's car and my car with out a wide band and it took many runs to get each car dialed in especially steves with his big cam and 9000 rpm redline. on my car i had to run it up in the hi r's coast to the side of the road check plug color. without a wide band that is how i was told how to tell if it was leaning out in my upper rev's. if you rev it and it leans out and then fattens up at low rpm's the plugs wont show they where lean. most people don know this and lean out there engines and pop detonation :( no more engine If i had a wide band o2 this would have taken a lot less time :) Quote Link to comment
ppeters914 Posted January 30, 2009 Report Share Posted January 30, 2009 I'm sure a Wideband Air Fuel Ratio Meter and/or ColorTune would be da bomb, but I should be able to dial in pretty close with my Uni-Syn: Quote Link to comment
DISLEXICDIME Posted January 30, 2009 Report Share Posted January 30, 2009 After a while you will not need the uni just a piece of hose o listen with i dont even use the uni most of the time Quote Link to comment
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