R.J.

Hey guys, is this an easy swap? I have the complete 944S donor car with everything. Search results showed the 16 valve motor goes in to another '87 8 valve car easily enough but no mention of the 85.5. I know the late 8 valve cars are all pretty similar but I don't want to have a Mickey Mouse install. Other than the DME harness, igniter harness, engine management computer, transmission, what would be involved? Thanks for any input.

sharky47

It should work - I know there is someone here who has a car like you propose building - not sure what year it is.......

R.J.

Great! Anybody know who that is doing the swap right now?

jgporsche

you need to get 944S/S2/968 fuel lines..... 8V fuel lines are different.

V2Rocket

You don't need to change the tranny...

and (correct me if I'm wrong) aren't these motors all cast with the same mounting points/holes etc? It should be fairly simple if you have all the electricals and fuel lines etc.

harrisonrick

V2Rocket

+1

keep us posted...so I know if I should go buy an S motor.

R.J.

I know you don't need to change the tranny but I've got it anyways so might as well. As I understand, the gear ratios are better suited to the 16 valve motor's power band.

Jay W

Yes the 944S transmission gear ratios are slightly different from the standard 944. Does the 85 run? If you are only changing the engine for the slight horsepower gain than it may not be worth all the work. I have both a 944 and 944S that I drive on a daily basis and I have to say I like the power of the 88 944 better than the 87 944S. My 944S may need some tuning or fuel injector cleaning but it is kind of a dog.

R.J.

Well, the 85.5 needs an engine so I figured why not put something with a bit more power in to replace it, I'm in there anyways kind of thing. Your thoughts on the 944S are interesting. I drove the 'S' car that might be the donor and it didn't have the acceleration I was expecting. It's a low mile car and the compression looks good as do all the emission test results so I was thinking it may be a tuning thing. Is the mixture adjustable on the 16 valve car like it is on the 8? What else might make it feel slow? It's almost like my 8 valve felt just as fast if not faster! I can get the 16 valve car pretty cheap and I was hoping some tuning work and a chip might make it worth the effort. Should the 16 valve not have a seat of the pants superiority over the 8 valve?

ilikemy944

I just did this.

16V engine + 944 n/a tranny (short gears) = fun. I doubt I would have any problem showing an n/a the tail lights.

Mount holes will need to be drilled for AFM mount.
Have to somehow mount ignition module - we just welded the bracket on.

Otherwise once we had the engine ready to go in, and had the n/a ready for the engine (nothing in the way), we had the engine in, harness in, and running in 1 day - and I drove it home

Jay W

The specs say the 944S should have 30 more horsepower. This added horsepower is only found above 3000 RPMs where mine does have a bit of a kick but not much. I dont tend to drive the car at above 3000 RPMs most of the time so I never enjoy the extra power. My 88 does have slightly higher compression than the other 8 valve 944's so it is faster than most of the 8 valve ones.

The 944S does have an adjustable cam gear which changes the timing slightly and they say there are slight gains from certain adjustments but you will need 2 dial gauges and plenty of patience to adjust it. I had to adjust mine after I redid the head last year and the instructions are not as clear as they could be. Setting up the gauges and adjusting took the better part of an afternoon.

ilikemy944

Don't drive over 3000 rpm?
I don't drive under 3000 rpm.
I definately visit the red area on the tach every time I drive the car.

At around 4200 rpm you get a nice little kick, and another at around 5200 rpm.

Fun stuff.

V2Rocket

I pull out of my driveway doing 5500RPM in 4th gear.

Catfood

good call V2! I dump the clutch wherever I go! Its the only way to go! The S lives in the high portion of the tach, off the line they are comparable until like 30 miles and hour and rev band torque pulls you away! weeeeeeeeeeee!