I found a guy that has 30 or so 13Bs around but doesn't know what year each one is. I'm looking for an S5 to rebuild with my 12A plates. How can you tell a S5 block from an S4? I'm not sure how much of the accessory stuff is on each, so the more basic the difference, the better.

 

I'll give you my minimum knowledge. The S5's have an electric oil metering pump opposed to the S4 mechanical. The S5 plug holes are farther apart then the S4. S5 no egr valve.

 

Is there a computer or anything to the OMP or is it just 12V? Basically, could I retain it for use in a FB

 

Computer controlled through imput from throttle position sensor, I believe the wide band. A lot of the guys with the S5's are opting to go pre mix and eliminate the electric omp. I suppose anything is possible, but probably more trouble then it's worth.

 

Rather than going premix i'd swap front covers and install a regular S4 mechanical unit. As long as your system is working properly you have no need to go premix it's simply a matter of opinion. There have been previous threads on this topic so i wont get into it.

And also like Turbonut said on the Intermeidiate (sp?) housing of the S5 (89+) there is no EGR valve. the S4 block will have the EGR in place.

-Markus