A question of carbs

[Dan]

I've been thinking about a triple carb set up and was wondering what things should be considered before installing such a set up. Currently my 72 has the stock L24 with a few mods i put on such as msa 6 into 2 headers, ZTherepy SU carbs with air horns and filters, a 2.5 exhaust, and a crane electronic igniton. I also took off all the smog stuff like the air pump and air galley. I invested the money for the ZTherepy carbs so this is not something that's going to happen right away but i know there are members with experience with triple carbs and i'd appreciate their input. Should i dump the L24 before i really get serious with triple carbs, or can good hp be found in this engine with the right set up. Do triple carbs require an electronic fuel pump or can the mechanical unit do the job. Mikuni's or Webers?.

[Royce]

I haven't used a triple carb setup but I think with a stock motor/head you will not really benefit from a carb change, especially since you have a great set of SUs from ZTherapy. I think you would be better surved to do some head -cam, valves, porting, polishing.

I have considered different carb setups but have spoken to enough people-Rebello, ZTherapy, etc. who say that unless you have a very trick motor the triples are not going to do any better than a good set of SUs.

I am staying with the SUs.

Have fun!

[Dan]

Thanks Royce

[2ManyZs]

I agree with Royce. If you have invested the money in the ZTherapy SU's you already have all the carb you will need. Triples would be just more money and then you would have to spend even more on engine mods to make them work as well as what you have. Just a second opinion.........

[Dan]

Thanks guys your opinions are much appreciated. I do like my ZTherepy carbs but the quest for more HP haunts me haha.

[guy_geo]

I've heard horrendous stories about tring to synchronize the 3 carbs also.. Need to be tuned weekly apparently also.. Not for me, oem SUs are ok!

[2ManyZs]

Well Dan, the quickest, easiest, and cheapest solution in your HP quest will be to unbolt your head from the L-24 and bolt it on to an L-28 short block.

[Daniel]

Remember the leaner the better(to a point).More fuel does not equal more horsepower.One thing I have learned through the years is Datsun really did their homework.Although there are many aftermarket products that boast better performance.When it really gets down to it for quality,performance and dependability,it's hard to beat stock.Of course if you deviate from standard,diff. heads,cams,cranks etc,things change.Also keep in mind that race car parts always need attention.I'm sure 2manyz's will agree.You don't race and go home and park it until the next time.You go home hoping to have enough time to get it back in adjustment.So we need to decide which path fits our lifestyle.Work on it when we want too or because we have too. Have fun!! Daniel

[Doehring]

Hi Z-friends, I have 2 '72 240Z, one with SUs, 6 to 2 header and original exhaust system and one with 3 Double SKs(with horns), 6 to 2 header, turbo muffler, Crane ignition, el. fuel pump, el. fan, add. oil cooling, but stock cam. #1 Z is my "elegant" Z, quiet, comfortable and it has a radio. # 2 is my beast: Loud, tough and with direct response. The radio that was in at first was the first thing I took off. The sound of the engine is the best music to me.

Looking at a stop watch there is no big difference in acceleration or top speed while both cars have the original cam and head. Different are fun, fuel consumption (not that much) and maintenance. Finetuning the 3 SKs is a science of it's own, but I like it! Which car I prefer ? It's depending on the purpose , on the kind of roads I plan to drive and on my wife. She prefers the yellow/white (interior) #1 with ( basic original) leather seats to

the racing seat and harness in #2, but there she misses the sound , the feeling and the attention from outside.

Rolf

[Dan]

I was cruisen around the site last night and i thought i saw something on triple SU's. I have never seen triple SU's on any 240 i have seen . They must be rare, i would imagine that you would have to build a custom intake manifold for them. Anyone got the 411 on triple SU's.

[2ManyZs]

There is an article in the old Z CAR magazine where the author built up a short stroke motor and had a custom intake built for triple SU's. Nov 1997 issue.

Of course it didn't hurt that his father-in-law owned a foundry so he made up wooden patterns and had a custom intake manifold built for the center carb.