Ok, I'm new so don't bash me too hard. Right now I'm a current Ford Ranger enthusiast, but I'm strongly looking at getting an RX-7, and I mean strongly. I was just curious what year was the strongest, or should I say quickest RX-7 in the second gen N/A, and Turbo. I love the way the FC looks. Anyways, I have a friend that claims the 1989 model to 1992 was the best, and that his 1987 isn't quite as strong. If someone could please help me it would be greatly appreciated.

 

2nd gen rx7 are divided in two series.
s4 : 86-88
s5 : 89-92

s5 t2 are boosting a bit more, and produce arround 200hp in stock form (2 or 3 psi)
s4 t2 are lighter and produce 185hp stock form.
the main difference betwen s4 and s5 is the oil meetering pump(omp). the s4 omp is mecanicaly controled while the s5 got an electronicaly controled omp. this oil meetering pump lube your rotor's seals. if they fails, you blow your engine. i've read somewhere that s4 omp is bulletproof, but since runing premix (mixing 2stroke oil with their fuel) eleminate this option, it is no more an issue for me.
compression ratio is lowered and rotor weight is also reduced on s5 models.
but at same boost, s4 and s5 do the same power

as for the weights (5 spd only, dont wanna type the whole tab) :

86 (all n/a) : 2,625 lbs.

87 n/a : 2,700 lbs.
87-88 turbo : 2,850 lbs.

88 n/a : 2,720 lbs.

89-92 n/a : 2,857 lbs
89-92 turbo : 2,987 lbs

vert are also heavier and did only came out N/A from factory

 

I think right now, I'm just going to be looking for a N/A 7. So really the weights and oil pump are the differences between the 2 series?

 

and exterior design. remodled front end and tail lights on s5
n/a s4 : 146hp
n/a s5 : 160hp

 

but with some money dropped into an n/a engien you can easely achieve ~230hp.

 

but with some money dropped into an n/a engine you can easely achieve ~230hp. even more if you want to get serious, arround 300hp. but bridgeported, high reving engines are not 'streetable'