R.J.

Well, it seems like the 8 valve motor might be better suited for my driving style. I prefer torque to be available in the lower rev range, I just don't shift every shift at 4 grand anymore. Would adjusting cam timing, a better engine management chip, and a free flow exhaust bring the torque curve down lower to where the 8 valve is? Is there anything that can be done to make it comparable to the 8 valve within a reasonable budget?

ilikemy944

What are you trying to accomplish?
If you aren't driving over 4k rpm you aren't going to notice a difference...
Why do the work if your car is running?
There are things you can do to the 8v to make it more powerful if that is all you are looking for.
I probably wouldn't pull a running 8v apart to put a 16v engine in. Sure its more fun, but there are things you can do to the 8v engine also...

I probably wouldn't do the swap just to gain 20hp.

R.J.

The timing belt broke when the water pump pulley on the previous owners rebuilt waterpump install seized. So, best case scenario head comes off, replace some valves, put a NEW waterpump in it and button her up. But....I have an '87 944S that I can pick up cheap, like less than 2 grand. But the thing is a write off rebuild and the front end has been 'clipped' and needs paint and bodywork and just doesn't look right and prolly never will. Low miles on it, about 75000 verified by the good folks at CarFax. So, I feel the temptation to plunk the 16 valve motor in my otherwise mint 85.5. I'd be doing the install myself and quite enjoy spinning wrenches from time to time. That's how I've got to this point. I'm looking to you guys with real world experience with both motors to help me make a good decision. Thanks for all the input so far.

ilikemy944

My 8v was sitting on the floor and needed an oil pan gasket.
If you are gonna be working on it, then go for it :P
I like the 16v a good bit, but the difference isn't there until way up the rev range.

R.J.

So, would it be safe to say the power up till about 4 is roughly the same between both motors and revving it above 4 gives a substantial increase for those times in traffic when you just need to get past that Honda, or is it just a dog till about 4? Would keeping my 8 valve tranny with the 16 valve motor give me more low end pick up?

Dan Shea

I just finished dropping a 3.0l 16valve in my 85.5, HUGE difference. The thing actually has some torque now.

You don't need to swap fuel lines, if you have the old engine (which you do) just take the pressure regulator off of it and use that. The only thing that is different between the two is the 16v uses a threaded fitting for the reg. while the 8v is just a slip fitting.

The external ignition amplifier was a pain to install. i had to do a custom wireing harness for it because my motor didn't come with a plug for it.

Most of the mounting points are already on the body for the afm braket. But the S2 afm is different from the S.


-Cheers

Jay W

Yes I would say the analogy that they are the same up to 4,000 RPM and the S is better after that is true. My particular car probably needs some tuning so it is slower under 4,000 RPM. I revved mine up getting on the highway this morning and I did feel the extra push at about 4,000 but dont expect anything like a ride in a turbo. I would say your best bet is to get the 944S for as cheap as possible and sell the motor to someone that has an S with a broken head and a great body/interior. There are alot of broken ones out there because of the chain tensioner systems. Then part the rest of the car and make some money to fix your 8 valve engine with.

Now if it was the 3.0 liter S2 motor that you wanted to put in it, that would be the thing to do. They are so much more powerful.

R.J.

Interesting thoughts Jay, sounds like it's not worth doing. I don't think I'd bother buying it just to sell the motor to someone. It's cheap enough to just swap out the 8 valve head, I don't need to part out the 'S' to finance such a cheap fix. Seems like the power to cost ratio just isn't worth it unless it was an S2. I'm guessing even with some chip tuning, cam timing adjustment and using the 8 valve tranny still wouldn't make it worth the effort?

ilikemy944

I'd say still under 4k its more powerful. But I don't know if its worth buying the car to yank the engine out of. Still though, check out this dyno chart, a baseline and with the 944SMax chip.

Here ya go - yep, that's wolf macleod's dyno chart, and one I swiped off of Russell's page.
The S chart is w/ and w/o his chip.

That S makes lots more hp and more tq. Fun stuff. The torque curves are similar except the S doesn't drop off near as badly past 4k rpm. The hp curve is very similar until around 4500 where the S keeps going up.

Those are basic opinions from me (ie. take with a grain of salt), someone who is biased.

I would do it if it were cheap enough - I did do it, after all. Although next time I'd pick up a 951 engine - but then again, I'm addicted to boost.

R.J.

Well, cheap enough is relative. I can buy the car for about 2k, sell the 4 way power linen seats, leather option door panels, dash and center console, and low mile tranny and recoup a nice chunk. From that point its just my labor and if I can get it all done over a weekend I'd be happy. I just need to decide if the slight but noticeable power increase is worth it. That's where I'm at. Anybody know what kind of rear wheel horse a chipped 85.5 8 valve puts down?

billthe3

If the donor car is in driving condition, why not just part out the one with the blown motor? (Did I miss this earlier in the thread?)

R.J.

Yep, mentioned near the top of the page.

billthe3

Ah, gotcha.

ilikemy944

Sounds like the S may be a good deal then - I'd go fer it :P

Edit: If you come to GA I'll let you drive it