G'day..

I've just installed a new set of DCOE45 webbers and a rather

crazy 0.33" lift, 38-78-78-38 degree camshaft to my zeds L28.

(picture attached).

While the car is a bloody hoot to drive out on the highway,

in congested traffic with 40 deg.C + summer weather down here

in Australia, all the hot air rising from the headers (which

invariably gets sucked straight into the carb's) turns the car into

rough idling pig (that cam doesn't help either!!).

I would like to fix this problem by fabricating a large,

rectangular "air box" which will bolt straight onto the carb's

(the ram-tubes will be retained within the box) and ducting "cold"

from an air filter mounted outside the engine bay.

While this will definately fix the hot air problem, I am worried that

it may restrict the air flow excessively.

Also, if I duct the cold air into the front of the box, will I have

a noticable problem with cylinder no.1 running the leanest and

no. 6 running rich?

I have searched the net, read a lot of stories from people

complaining about similar hot air problems, but I can't find any

info about air boxes/cold air ducting.

So, if anyone out there has experience doing what I intend to do,

or can direct me to any info. on the web, it would be appreciated!

Cheers,

Glen K

You don't really need a complete box around the carb intakes. What I suggest you do is two things:

1. Build a heat shield between the headers and the carbs that routs the heat rearward and up.

2. Add an opening in the hood (probably use a 280Z hood) that lets that heat escape.

At low speeds you have to use convection to get the heat out of the engine compartment.

TWM fuel injection does direct port fuel injection systems for 240-280z's, they currently offer a cold air box for their fuel injectionsystem that would work for your application.

My car also used to be very rough idling, but it was because the carbs were getting hot because of the heat rising from the header. I remember I could barely leave my finger on the carbs for more than a few seconds it was that hot. I then built a cheap heatshield and kept the heat away from the carbs. I could then keep my finger on the carb all day long if I wanted to. It idles just fine now, the Mikuni 44's were not happy being hot!!!

In Australia where temps get really hi, you will need a heat shield or even two

In Australia where temps get really hi, you will need a heat shield or even two

You do realize that you're responding to a thread which was last responded to on 01-27-2002....?

Edited June 27, 201014 yr by sblake01

Better late than never!