Jump to content
HybridZ

Su's what exactly do i need?


Recommended Posts

I'll try. I am assuming you already have the carbs...

 

1) remove all EFI related equipment. AFM, thermotime switch, cold start valve, EFI ECU and related wiring, intake manifold with injectors, high pressure pump and regulator, etc. The EGR can remain.

 

2) Sell the EFI ECU, fuel rail and AFM to buy an N-36 intake manifold (any SU manifold will work, it is rumored that the N-36 gives better performance, but I have never seen PROOF) and an intake gasket. I am assuming you have a P-79? It will bolt straight up. You may have enough $$$ to purchase a stock orange air cleaner with all the vacuum line stubs, as well.

 

3) Find a low pressure pump (electric) or install a mechanical pump, and a low pressure fuel rail.

 

4) install new SUs with intake, and hook up fuel rail.

 

5) purchase the Just SU video from Z Therapy as well as a unisync tool.

 

6) you don't live in a very cool climate, but you may wish to install the choke cables to the cabin.

 

You should be in business.

 

Anyone else have suggestions?

Link to comment
Share on other sites

You can do without the fuel rail if you get a "T" or "Y" fitting and split your line over the valve cover. Make sure you get the round top SUs, not the flat ones. The Puralator 4-6psi electric pump commonly sold at Advance Auto parts is only like $20, and will work very well for this application. I ran SUs with no filters, don't really recommend that, but there are more filter options out there than the factory box. K&N actually makes a bolt on filter for that application. I live in Florida, and cursed out my non-choke cable having SUs every day I tried to start them before 10am, so I highly recommend you install the choke cable.

Link to comment
Share on other sites

You can do without the fuel rail if you get a "T" or "Y" fitting and split your line over the valve cover. Make sure you get the round top SUs, not the flat ones. The Puralator 4-6psi electric pump commonly sold at Advance Auto parts is only like $20, and will work very well for this application. I ran SUs with no filters, don't really recommend that, but there are more filter options out there than the factory box. K&N actually makes a bolt on filter for that application. I live in Florida, and cursed out my non-choke cable having SUs every day I tried to start them before 10am, so I highly recommend you install the choke cable.

 

 

 

How would i put a choke cable in my 280z? i live in vegas it never gets cold here.... i got the su's yesterday for 50$! and im gettin them rebuilt.... does anyone have pix on how to do the "fuel rail" with the T valve? and what size tubing do i need? and how do i install a fuel pump like that is it a direct bolt in??

Link to comment
Share on other sites

Hmmm, thought I had a picture of my car with SUs on it in running condition, but all I could find was this pic of the engine on a stand outside of the car...

Image2.jpg

The choke stuff should have come with the carbs, if not, you may be able to rig one up with a universal choke cable. I've never done it, so I don't feel confident trying to talk you through it. as for the T fitting, look closely at this pic of my engine fuel injected, and imagine that instead of a fuel rai, those two braided lines went straight into the fuel bowls of the SUs:

DSCI0015-1.jpg

I actually ran that exact setup, but instead of the AN fittings I just had hose clamps on the carb fittings. You don't need braided AN line, you can just get 5/16" fuel line (I think that's the right size, it's been awhile...)

 

Keep in mind you do NOT want a "T-valve", what you want is a "T-fitting". If you go shopping for a valve, you won't get what you need. You are just trying to split a single line into two lines, you don't need the capability of closing one off.

Link to comment
Share on other sites

Well me and a buddy took everything off that is not needed, and the car is ready for its su's, the exhaust got blown up! like the muffler blew in half im assummin thats why it shot a fire ball and sounded like a gun shot...

Link to comment
Share on other sites

do i need the air box to run the carbs?
Actually, if you take off the backing plate with the air horns, you may notice it doesn't pull as hard at high revs. The air horns are an important part of obtaining good airflow into SUs as they help straighten out the flow before the air enters the throat. If you tune for power without the backing plate and later add it, you'll have to do it again.

 

This was one of those things I learned the hard way.

Link to comment
Share on other sites

Actually, if you take off the backing plate with the air horns, you may notice it doesn't pull as hard at high revs. The air horns are an important part of obtaining good airflow into SUs as they help straighten out the flow before the air enters the throat. If you tune for power without the backing plate and later add it, you'll have to do it again.

 

This was one of those things I learned the hard way.

 

 

ok yea because i know a guy that has the air box just havent gotten to get ahold of him... but i need the car runnin for work so its not 100% needed but the car will run with out them if i got this straight...

Link to comment
Share on other sites

I can't tell from your original post if you have flat top or dished pistons. With dished I'm sure as spacecase70 says, you can run regular just fine. With flat tops, you can certainly retard your timing with regular, but premium would probably let you advance a few more degrees which on a stock motor should give you a little more HP and even slightly better economy on the highway as well. But just to be clear, the differences I'm describing would be hard to feel on the street.

 

Of course, either way (regular or premium) you should tune for that fuel. In general, you probably want to get to 35 degrees of total advance with your engine. If you can do that with regular, then you save a few cents per gallon :)

Link to comment
Share on other sites

Congratulations!

 

Did you run into any problems? Are you running chokes?

 

 

no chokes.... fuel pressure was a BIG PROBLEM! but that was solved.... and yea.... i was thinkin maybe i should do a write up and all parts that i used and things i did to bypass things and what not... good idea or not?

Link to comment
Share on other sites

  • 2 months later...

kinda related, not worth a whole new thread...

 

I've got a 240z with some Webers that I have no idea on the history of them, therefore I'm reverting back to a stock setup for a cheap, fresh start. I've got a set of stock 73 SUs, however when I went to put them on, I discovered that apparently the PO replaced the manifold too when you switched to the webers.

My question is, does it matter what head the new manifold came from? Mine is an E88, do I need to find one from another E88? Aside from the manifold, what else do I need to get my hands on?

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...