2.3-16 changes after 1987? Curious.
 

Did the horsepower increase, and what other changes took place in the 2.3-16 after '87. I know they weren't imported, and were supplemented or replaced by the 2.5 engine, but am curious how much the 2.3 was improved, if at all. Would a later motor retrofit to a 1986? If so, what mods if any?

Most of the changes had to do with durability! & of course the 2.3 was turned into a 2.5. Larger oil pump, double row timing chain, & better cams were some of the changes.
Not much that can be retro-fitted w/o spending big $$$$.

Is that to say that the 2.3-16 wasn't improved for 1988 and was eventually replaced by the 2.5-16 which was an improvement? Will a 1988 2.3-16 motor bolt into a 1986 2.3-16 five speed and hookup electronically, electrically, etc.?
Thanks.

Up to 86 had >> straight LSD
Post 86 had >> ASD with LSD

From 88 was 2.5 - reinforced block, in-house cylinder head, different internals, duplex timing chain, different injection widgets,

Ride height adjustable suspension was optional (as per the standard Evo models.)

Just lots of little tweaks really.

Mate of mine has a 2.5-16v and whilst its undeniably nice, its no faster than the 2.3-16v (not on the road anyway) and it lost a lot of the 2.3-16v rawness of character

Do a part number check on the ignition and injection systems - the 16v were a bit parts bin specials, and different chassis number ranges had different bits.

The biggest difference will probably be the Fuel Distribution unit, SLS pump, and CIS-E module.

I am curious, what is the difference between these two diff's?

Up to 86 had >> straight LSD
Post 86 had >> ASD with LSD

LSD is just an LSD - 8 clutches per side. Preset tension - no control other than the things heating up.

The ASD diffs use pressure from the SLS system to fiddle about with the locking point of the diff. I think this only works below 17mph though - anything above that and it operates like a normal LSD.

Simple!

Thought I'd explained this fully over on 190 Rev? :D

The US spec 1987 16 valve does not appear to have ASD, I have one and there is no ability to hook it up to an SLS and the only sensor input is for the ABS. The only listed difference between the 1986 and 1987 is a mid year change in 1986, starting with VIN number F222285 forward. This is what I have.

The 1992-1993 W201's had a ASD option but not connected to a SLS system, so it must be fed differently.

I also found this:

The "ASD" was used in the late eighties and early nineties as limited slip differential in some Daimler Benz cars.
I know that it was fitted to the "E 34" – W 124.031/M 104.980 3.4 as well as to the Coupés and Cabrios running with the 3.4 Litre inline engine.

This system was limited up to speeds of 35 km/h {22 miles}. At higher speeds it runns as al limited slip differential with fixed lock ratio.
The "ASD" system is using a Differential with ring cylinder and multiple disk clutch, oil reservoir, oil pump, hydraulic unit with accumulator and single solenoid valve, wheel sensors and controller. Pivots or if both drive wheels turn 2 km/h faster than the front wheels, then the ASD is activated. The hydraulic unit is headed for and a pressure of 30 bar affects the ring cylinders of the half axle. The bevel pinions are pulled outward and close the differential. At higher speeds, in the sliding run or when braking the multiple disk clutches work like a limited slip differential with fixed lock ratio. Up to 35 km/22 miles the lock ratio is between 35 – 100%

Thats about right for a UK 2.3-16v post 86 - all the 87 onward cars I've seen have ASD. With all the 86 cars (I've owned 2) having LSD only

Am I wasting my time dreaming of owning a 2.5-16 EVO l or EVO ll. It's the "rawness of character" of my 2.3 16v that excites me, and I thought a 2.5 EVO would give me an even greater fix. Please, tell me it's so!

Kirk1, You might want to read this article snippet about the 2.5-16, the EVO and EVO II engines.

190Revolution.net