Carbs?

[backer240]

I've just began working on my 240Z and i've begun thinking about different preformance options. Right now on my Z there is Weber DGV carbs, I'd like to install triple webers but the price is a little high for a kid like me. I stumbled upon the option of installing a 4 barrel carb using the manafold from MSA. Which will deliver better preformance, the DGV's or the 4 barrel conversion?

[Cary67]

I had the four barrrel conversion for a while and it was ok. However, I eventually went back to the original dual SU setup. The design of the 4bbl manifold makes it so #1 and #6 run too lean and #3 and #4 run too rich. There is a reason that Nissan went with twin carbs. The same reason makes it so triples are even better. If you look at the triple carb intake manifolds, they are pretty much uniform in length and offer a straight shot to the cylinders. Compare that to the 4bbl manifold and you will understand the design flaw. FWIW, the flow characteristics of the DGV manifold adapters (which I think attach to the stock manifolds) are almost worse than the 4bbl manifold, in my opinion. They basically attach down draft carbs to a side draft manifold. They send the flow down and then back up and then to the side. That just can't be efficient.

The general opinion I have seen of the DGV's is that they suck. So, to answer your question, the 4bbl is probably better than the DGV's. If you go with the 4bbl, be sure to not go any larger than the Holley 390. Even the 390 is oversized for a 2.4 liter engine.

However, if you can't swing triples, you should be able to pick up a set of used round-top SU's for way less than the cost of the 4bbl manifold and Holley 390 (especially if you're planning to bend over for MSA....)

Hope that helps. Good luck.

[ZmeFly]

the dgv's if jetted properly will give you great performance. i had a 72 with them and they were really good till about 5500-6000 rpms, then they would lose power to what seemed to be lack of fuel.

i think if i had played with the jetting they would be an excellent carb to use but personally from a stand point for more performance you would be better off with a set of dual su's, not to say the webers arent good.

but to get the proper set up with the right jets and so forth can get expensive quick.

whatever you do stay away from the 4barrel set up. its just worthless, in my opinion.

the triples wont do squat for you except suck up loads of gas unless you have the engine to use them.

[beandip]

4 barrel carbs, they work great on V-8s because they set right in the center of the engine. Multis work the best on inline engines just like cary67 found out. What are you wanting the car for ? A full out raceing or street driver , or for looks and racer wanta be ? The SUs will deliver all the fuel needed for any street driven L engine , if the right needles are used. Tripples will give more power if you are running a cam and headers and large plumbing running high Rs most of the time. Other wise properly tuned doubles . There is a guy running in the 12s using SUs , and he drives the car on the street, Normthe12secdude he is on Zcar.com all the time . Check him out . Good luck:bunny: