Spfi vs. Mpfi
Which is preferred for highway driving?

 

MPFI is better, gives the car a smother idle.

 

So if I want a loapier growl...go with the spfi...yes? Or is it morecmplicated than that ?

 

No, would be WAY to hard to convert, would be much easier to get cams.

 

But some early model xk8's come with spfi specs. Changes to mpfi after 2000 / 2001 model year. At least that is what I am seeing during my search.

 

That is not correct, all XK8/XKR models are MPFI. If you want a loapier growl, you can modify the exhaust.

 

OK guys. For us Neophytes what does SPFI and MPFI stand for. I love it when you guys us abbreviations.

EZDriver

 

Sequential Port Fuel Injection (Each Injector Fires Independently).

Multi Port Fuel Injection (Groups of Injectors Fire Simultaneously).

 

Actually, The 1997 XK Product Guide specifies that "The Fuel Injection System Operates Sequentially".

The Electrical Diagrams (for 1997 and 2000) show a individual ECM Output for each Injector.

 

Hello. Paul or mr.pavlik? Would you happen to have any knowledge of which year model jag has the more muscle car sound to it...the early models with spfi or the 2000 models with multiport?thanks ��

 

The termnology is getting confused.

All XKs are multiport fuel injection (MPFI).

From Wikipedia:
Multi-point fuel injection injects fuel into the intake ports just upstream of each cylinder's intake valve, rather than at a central point within an intake manifold. MPFI (or just MPI) systems can be sequential, in which injection is timed to coincide with each cylinder's intake stroke; batched, in which fuel is injected to the cylinders in groups, without precise synchronization to any particular cylinder's intake stroke; or simultaneous, in which fuel is injected at the same time to all the cylinders.

SPFI is single point fule injection. From Wikipedia:
Single-point injection uses a single injector at the throttle body (the same location as was used by carburetors).
It was introduced in the 1940s in large aircraft engines (then called the pressure carburetor) and in the 1980s in the automotive world (called Throttle-body Injection by General Motors, Central Fuel Injection by Ford and EGI by Mazda). Since the fuel passes through the intake runners (like a carburetor system), it is called a "wet manifold system".
The justification for single-point injection was low cost. Many of the carburetor's supporting components- such as the air cleaner, intake manifold, and fuel line routing- could be reused. This postponed the redesign and tooling costs of these components. Single-point injection was used extensively on American-made passenger cars and light trucks during 1980-1995, and in some European cars in the early and mid 1990s.


Most cars from the mid-nineties to the late 2000s were MPFI. Many cars are still MPFI, though more recently direct injection (basically MPFI directly into the cumbustion chamber, after the intake valves) has begun to take hold.

 

As WhiteXKR says, all XK8s/XKRs use the Sequential version of Multi-Port Injection.

Acronyms can frequently be confusing and should be avoided unless their meaning is obvious.

In my opinion, Throttle Body Injection (TBI) is the best description of Single Point Injection.

Also, Mr. Pavlik is my Father.