SU round tops vs dual 32/36 Webers

[Jeff Berk]

I felt a little deflated when I first saw my 260Z because according to the documentation, the car once was equipped with triple Webers. By the time I got it, the Webers had been replaced with round-top SUs. The SUs are working fine and I rebuilt them a couple of years ago with components from Z-therapy. The engine is a bored 280, with non-stock pistons, cam, headers, etc. so I thought the SUs might be limiting the engine. The SUs are so simple that I don't know if I should consider them elegantly designed or an overly simplistic approach to carburetor design. I've rebuilt typical American carburetors in the 70's so I am comfortable with complex carburetors that lack an oil dip stick.

I don't race the car except for autocross which I've not done since before Covid. I'm a little stretched for funds but there is a local Z owner doing an LS swap that is getting rid of some components and is asking a reasonable price for a dual weber conversion kit:

https://www.facebook.com/marketplace/item/820044696097399?hoisted=false&ref=search&referral_code=null&referral_story_type=post&tracking=browse_serp%3Aa9e2d1ce-a84b-4e85-a9e8-cbcbc87462d8

I'm low on funds because I just spent $800 on leather door panel, center console, and dash covers. All this leather smells good, definitely better than the mildew odor when I first got the car. Most of the mildew odor went away when I pulled out the shag carpeting.  But I digress. 

[SteveJ]

I had the dual Webers on my 240Z when I first bought it. Andy Craig suggested I convert to SUs when I went to him to rebuild the engine 27 years ago. I agreed and never looked back. I think I sold the Webers about 18 years ago.

When you consider a member over at Zcar.com got a Z into the 12 second range on SUs (https://www.zcar.com/members/norm-the-12-sec-dual-su-dude.1912/), I don't think the SUs are holding you back too much if they are in good shape and balanced properly.

[Patcon]

I would not consider those webers an upgrade to the SU's!

Even triples might not really be an upgrade. Properly tuned SU's can support a  lot of motor

Steve beat me to it...

Edited September 29, 2022 by Patcon

[Jeff Berk]

Thanks, now I feel OK with keeping the SUs and not dropping another $750 into the engine.

[dutchzcarguy]

Also, when you drive the car daily.. those cars with the tripple webers are a pita when cold they always seem to run very bad ..  Lots of fuel is needed to keep them running..  I also took a look at a set of webers, dell orto's or better (More original) micuni's but they make not a lot of power extra and are expensive.  A extra is those SU's ( THEY ARE HITACHI"S !!!!!  DAMN IT!!  Not gonna say this AGAIN!  🤬 oeps...sorry...)  Are SO EASY to balance and tune!  👍

[Diseazd]

Keep the SU’s…..this video of Eiji (triples) vs me with SU’s. Both are stroker motors, but Eiji with more motor, but still competitive. I love ny SU’s. 
 

 

 

Edited September 30, 2022 by Diseazd

[26th-Z]

Eons ago, I road raced British cars with SU's and learned a lot about tuning them for performance.  Hitachi's are just the same and I would say if you wanted to play carburetor tuner, the Hitachi's would be fun and simple.  Read some SU tuning books.  You can get a lot out of a set of Hitachi's.