Possible replacement for Hitachi carbs?

[Darkstar]

Hi guys,

it's been about a month since I last posted here, as I didn't have much access to the Internet. I made a brief search in the Carbs section, but unfortunately I didn't found anything. Sorry if there's a topic like this.

I want to modify my engine a bit, and I've been considering various parts to use. First, I'll have to do a general rebuild with factory-specified parts, in exception of camshaft, which I would like to be a longer duration one, thinner head gasket (without raising the CR it wouldn't benefit much from longer duration), a better-flowing exhaust system including the manifold and small (but obviously imprtant) things like better plugs, wires etc. As far as I know, well set Hitachi carbs (round tops) would be sufficient for fast driving, but triple twin-chokes like Dellorto DLHA or Weber DCOE would result in better performance. BUT there's a drawback in form of more troublesome maintenance and worse fuel economy... Thus making it difficult to run every day. I thought of different carbs, and after leaving an idea of a 3 Hitachi setup fabrication I was left with nothing.

My question is - will a set of bigger bore carbs, like 2 inch Jaguar SUs, result in better performance? They should be able to handle the power, plus there's the advantage of possibly use the factory intlet manifold.

Best regards,

Tony.

[240ZX]

Certainly 50mm SUs do flow more however, with only the addition of a mild cam and a slight compression increase you will likely only need a little rejetting on the round tops. I know of people who are running 50mm SUs but, they are on extensively modified 2.8L and 3.0L L6 motors. Tripple Webers or Dellortos, given the correct sizes, will improve permormance. Initial set-up is certainly a little more involved than SUs but, when properly tuned they will net you very nice throttle responce...more $$$ of course! If you want some tips on improving your L6, convert your ignition over to the electronic type and circle file the points. Also, a lightweight flywheel will improve the reving capability of the engine. Additionally, swap out your 4 spd for a 5 spd as well as changing the differential gearing to match the 5 spd. The list goes on and on. In the archives, accessible with the search function, you will find just about any answer to a question regarding the Z and modifications. Sometimes finding the correct term to type in for the search is the hardest part. Good luck with your project. Time, money, and patients is all that is necessary!

[Kyle]

I've got SUs on a 9.5:1, port, polish, balance, cam, header, etc setup. They're fine. If you're considering going away from SUs, the only place to go is EFI in my opinion.

[Zedrally]

I'm with Kyle on this. EFI is my preferred option, although I hadn't considered XKE SU's, I would suspect that there would be few sets of these on the market.

[Curtis240Z]

I'm just getting my triple TWM throttle body setup going and it is so much nicer not having to deal with jets anymore. I had triple 44 mm Mikunis and while it was great the low speed driveability (<3000 rpm) isn't very strong. But this option is WAY more expensive than Mikunis!

[Darkstar]

240ZX, Euro spec cars came with 5 speed 'boxes from the factory, and my car has the "B" type (overdrive 5th gear) transmission, and, as far as I know, 3,90:1 R180 diff. I'll think of the electronic ignition. I will certainly change the flywheel and clutch - despite the fact that I won't be pushing the power over 200HP, the car will need to be durable enough to cope with more stress, as I will run it in rallies.

EFi seems to be a good idea (I've seen the ITB's on TWM site, are they only for the L28 heads?), but unfortunately the budget I can spend on the engine is quite limited - first I would like to tighten the handling a bit and make it go faster without touching the L24, and that's why I began to search for a good diff, gearbox and so on. Anyway, I'll keep looking in the carb section, hopefully I'll find something useful. Thanks for the replies.

Regards,

Tony.

[Curtis240Z]

.....EFi seems to be a good idea (I've seen the ITB's on TWM site, are they only for the L28 heads?), but unfortunately the budget I can spend on the engine is quite limited - first I would like to tighten the handling a bit and make it go faster without touching the L24, and that's why I began to search for a good diff, gearbox and so on. Anyway, I'll keep looking in the carb section, hopefully I'll find something useful. Thanks for the replies.

Regards,

Tony.

The TWM ITBs bolt up to any DCOE compatable manifold.