Carburetor Upgrades

[Vitamin Pepsi]

Hello! When I purchased my 280z a while back, it was owned by a guy who took off the fuel injection and put on some harley davidson carburetors. They're not the worst thing in the world, the car gets 31mpg on the highway, but if you put your foot down, the car suffers from major fuel starvation. I still have some of the fuel injection parts in a box, but chances are they're missing something. What would be the best course of action for upgrading the carburetors? I don't have $1600 to upgrade to triple webers. :(

 

 

 

[Pasquale]

If you look around people sell their triple side draft set-ups all the time (I just but a 40 mikuni set-up for 750) you can even pick up some nice SU's if you're willing to wait.

[Npdavies.]

Dual SU round-top carbs work really well, and you can get them for pretty cheap.

[Stupid_fast]

Is it possible to re-jet those bike carbs? I know the similar Mikuni designs are similar performance as SU's.

[Vitamin Pepsi]

Dual SU round-top carbs work really well, and you can get them for pretty cheap.

These are the carburetors found on pre'72 240zs, correct?

 

Is it possible to re-jet those bike carbs? I know the similar Mikuni designs are similar performance as SU's.

I don't know, I have no experience with jetting carbs.

[ggzilla]

You can tune the bike carbs to work well with a car, but it is carb tuning, so it's not a simple bolt-a-part-on process.

 

Getting the 240Z carbs (dome-top) is probably the easiest best way to go.

[Alex Datsun]

Im pretty sure you can sell those for good amount or even trade someone plus cash. That 31 mpg would make for a great class commuter. My friend has a set of Round top SU's for sale if your looking.

[Uraznfriend]

Wait wait wait... you get 31 on the highway??

 

thats way better than my dual webers, i honestly cant see why you want to change them

[ggzilla]

i honestly cant see why you want to change them

 

Because he said "if you put your foot down, the car suffers from major fuel starvation".

 

I'm guessing it's actually air starvation. Those HD carbs look smaller than the stock 240Z carburetor. The 240Z motor was 150HP and old harleys are 1200cc and less than 120HP

[Alex Datsun]

Wait wait wait... you get 31 on the highway??

 

thats way better than my dual webers, i honestly cant see why you want to change them

 

I ran the duals before i got my triple mikunis, there pretty decent but its hit and miss sometimes. Thats how mine was anyways.

[jalen]

I think dtp has some for sale for $900 obo pm him

[2fas4joo]

I'd probably get some SU's. I just bought the Z Therapy rebuild kit which comes with the dvd about the SU's. It doesn't look like they're going to be too hard to mess with and I rarely do work on cars.

[Sealik]

I'd probably get some SU's. I just bought the Z Therapy rebuild kit which comes with the dvd about the SU's. It doesn't look like they're going to be too hard to mess with and I rarely do work on cars.

 

Typically the SU throttle shafts are worn after 40 years of use...rebuild kits won't address that issue.

Need to be re-bushed

$325...Z Therapy

$100...Zeddsaver...although they are located north of the border and do not use the roller bearings as Z Therapy does...but guaranteed for life

[Stupid_fast]

These are the carburetors found on pre'72 240zs, correct?

 

 

I don't know, I have no experience with jetting carbs.

 

http://www.harley-performance.com/harley-carburetor-jetting.html

 

Can also drill out the stock main jets(with the right bits) to get it more rich.

Its probably the cheapest solution to get it running right. Those carbs are probably still jetted for a 2 cyl.

 

Honestly I think your current setup would be just as good as SU's when tuned right.

[Vitamin Pepsi]

Thank you for all the tips gentlemen! I'll buy some extra jets online and give 'em a try.

[WAGON JON]

Nice carbs!!