Intake manifold for side draft carburetor

[isuzu Specialities]

For 4Z series engines

[JoeIsuzu]

Are you trying to sell this, or just showing it off?

Jack

[isuzu Specialities]

Are you trying to sell this, or just showing it off?

Jack

At this moment in time I am simply letting it be known to all Isuzu people that a aftermarket product believed to have never existed is currently in production. This manifold is not currently for sale at this time. However it may be in the near future.

[gruff54]

What carbs would be run with this intake manifold?

Mike

[isuzu Specialities]

This manifold is made to fit dual Weber DCOE side draft. I have 7 SU type Zenith carbs laying around my shop that I had gotten about until recently.
These were used by MG, Triumph Morgan Jaguar Rolls-Royce, TVR and other euro manufacturers. I might be making an adapter to fit 4 Zenith. Performance wise they are far superior...

[gruff54]

I imagine an engine with dual Weber DCOE side drafts would be a high rpm engine more suited to a "street" vehicle? Would the Weber 36/32 downdraft would be a better choice for an off-road application needing more low end grunt?

Mike

[isuzu Specialities]

I imagine an engine with dual Weber DCOE side drafts would be a high rpm engine more suited to a "street" vehicle? Would the Weber 36/32 downdraft would be a better choice for an off-road application needing more low end grunt?

Mike

All fuel delivery systems it being SMPI or CIS type EFI injection to updraft or side draft carburetor all have their pros and cons.
Some options are fundamentally universal & some options are best suited for specific applications and there are hundreds of deciding factors to determine which system is best.

High RPM engine is not the goal because the 4ZE1 engine could never be that. The sure size & mass of the crank assembly, the large cylinder displacement and the lack of balance shafts is the limiting factors. Trying to get high RPM from this engine would only rip itself apart as its physically impossible to prevent it from vibrating. The cylinder displacement of this 2.6L engine is uncommonly large for a 4-cylinder. This large displacement gives the pistons a huge surface area and that is what creates engine torque. To increase the power output of this engine I am exploiting this fact & focusing on increasing the torque.

Combustion temperature & mass of rotating components is what controls the engine RPMs. The mass is already there. So I only need to control timing and fuel mix which can be achieved with any fuel delivery system. Now how to choose a fuel system?

The way to increase the power output of any engine has less to do with fuel amount and ignition timing than most people think.
It has everything to do with filling the cylinders with air. You can't burn more fuel without oxygen. Although light, air has mass and mass takes time to accelerate. With a carbureted engine your adding fuel to the air, this increases the mass even more & now it takes even more time to move this air/fuel mix (this is why EFI systems are superior) The intake and exhaust valves open for a split seconded limiting the amount of air that can potentially fill the cylinders. So the goal here is to accelerate the air as fast as possible, have it travel the shortest distance possible & to keep the valves open as long as possible. A side draft carburetor mount close to the cylinder head is ideal for the design goal.

A down draft carb sitting on top of a intake manifold will require the air/fuel mix to travel a longer distance and also change direction along the way slowing down the air speed.

[isuzu Specialities]

I discovered 1 new variant of Isuzu 4Z series engines. During that process, I discovered another engine that I wouldn't say is a variant, however a couple parts are possibly interchangeable, I have verified one part so far. This part started production in 1974 & is currently still being produced today.

I'm relieved that I do not need to make a coolant distribution manifold & thermostat housing from scratch with the high performance side draft intake manifold.

[isuzu Specialities]

the previous manifold I discovered is a good less expensive option however, its not quite a direct fit. I did know I was very close to discovering this new variant of Isuzu 2.6L 4ZE1 engine.

This research project of mine lasted about 11 months. Digging thru EPA documents, SAE database, reading press transcripts & magazine articles, emailing engineers & spending a few thousand dollars purchasing parts that didn't fit.

My persistence has paid off.
Prior to 20 seconds ago Isuzu people new and old whole heartedly believe these parts were never available for Isuzu 4ZE1 engine.

Behold... Aftermarket side draft carburetors & intake manifold complete with casted T-stat housing.

2.6L carb intake2.jpg (95.19 KiB) Viewed 61 times

2.6L carb intake 3.jpg (119.42 KiB) Viewed 61 times