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that's a great video, to show why the AFM is a problem for power.
notice how the flap only opens all the way a handful of times, at WOT, once the RPMs get really high.
the big spiral spring is designed to only open at full throttle above a certain RPM. I know contemporary BMWs that used the AFM have found it to be around 4500rpm, maybe higher depending on model.
so basically, below 4500rpm, you are running with a restrictor plate, and over that, the door still isn't fully open.
not coincidentally, looking at my most recent MAF dyno run overlaid with my 100% stock dyno...the power line really takes off at 4500+ rpm versus the linear increase below that.
So for the last several days I have been thinking a lot about the engine.
I don't want to think about the damn engine.
It's been a very time consuming (and finally... at times ultimately satisfying) aspect of the car.
The 944 2.5 n/a is not *all about the engine*. So why am I semi-fixated?
Dunno.
HERE are my thoughts:
I am 90% extremely happy with my engine. If I could have another 10-15 hp I'd be even happier.
The "S" engine won't give me that. I don't think an S is more powerful than my 8 valve is presently.
That has always been my personal goal, make my engine be about the same power (or even a bit better) than a stock "S", but with the benefits of the 8 valve (such as more readily available parts, simpler: more reliable).
Wilson is there. The "S" engine pulls so silky smooth and meets emissions requirements, where as Wilson's engine is like a rumbling, cracklin' race engine... but we both get there.
Definitely willing to help with a game-plan if you go that route. The S motor has a lot more potential to make NA power... it has more aggressive cams than the S2 and 968, higher compression than the 8v, and responds better to intake/exhaust mods because of the better flow.
Just with bolt-ons and a better (DME) tune, you might even walk away with 200bhp. With a speed density distributorless setup, even more because no AFM and more precise spark timing + hotter spark at high RPMs where the S likes to sit.
10-15bhp is waiting for you (pretty easily) in the open-intake pipe and tuning department.
MAF or MAP, pick your poison...Dr. Sausage should be able to hook you up pretty quickly if you do.
My MAF and +2 degrees advance on the stock early camshaft (the less-aggressive 944 cam) has given me +17hp and +27tq (crank) over stock ratings. With your hot cam, (did you do head work?), ditching the AFM should yield even bigger gains for you.
I am 90% extremely happy with my engine. If I could have another 10-15 hp I'd be even happier.
The "S" engine won't give me that. I don't think an S is more powerful than my 8 valve is presently.
That has always been my personal goal, make my engine be about the same power (or even a bit better) than a stock "S", but with the benefits of the 8 valve (such as more readily available parts, simpler: more reliable)"
I 100% agree with you.
Have had the same thoughts. And are also aiming at 200 hp. on a 8 valve.
I thing you should go for a MS / MAP solution. Will give you the 10 hp. You are missing.
And open up for all sorts of fun. ITB's, Faster cams.
So for the last several days I have been thinking a lot about the engine.
I don't want to think about the damn engine.
It's been a very time consuming (and finally... at times ultimately satisfying) aspect of the car.
The 944 2.5 n/a is not *all about the engine*. So why am I semi-fixated?
Dunno.
HERE are my thoughts:
I am 90% extremely happy with my engine. If I could have another 10-15 hp I'd be even happier.
The "S" engine won't give me that. I don't think an S is more powerful than my 8 valve is presently.
That has always been my personal goal, make my engine be about the same power (or even a bit better) than a stock "S", but with the benefits of the 8 valve (such as more readily available parts, simpler: more reliable).
Wilson is there. The "S" engine pulls so silky smooth and meets emissions requirements, where as Wilson's engine is like a rumbling, cracklin' race engine... but we both get there.
I'm also curious what my engine will have at the end power-wise.
The Augtronic + cam + balance shaft delete proved to be just 16 hp under regular S2 engines (that would make it 195 hp). I've got a bit of extra ccm so we'll see.
I'm still early at braking it in and I'm happy if I've got no issues. Performance is secondary atm.
I'm also curious what my engine will have at the end power-wise.
The Augtronic + cam + balance shaft delete proved to be just 16 hp under regular S2 engines (that would make it 195 hp). I've got a bit of extra ccm so we'll see.
THAT 195HP....
is that with your current 2.9L or with the old 2.5L?
either way, very nice
Have a head to match. And ecm/afm. Missing some small bits. Cams look GREAT at first glance. Piston disagreed with a couple of valves (and the big guy won).
Less damage (at first glance) than I suspected... but there have been several people handling this stuff resulting in small bits that have been lost.
Looking at the 944Online.com diagram... sheesh these engine look complicated. I was thinking about building it up (hot rodding it), but now I dunno if I want something this complicated under my hood.
Fix it and use it, the 16v really is not worse than the 8v to deal with. Timing the cams is the hardest and you have to do those cam pads. Hell i have a set of pads for an S/S2. PM your address and pay shipping and ill send them your way. i have a 944S afm i can send your way too if you want it. Its not doing me any good sitting in my office.
I'd build the S motor personally, The head flows so much better than the 8v and in stock form pulls all the way to 6850. You have a rowdy 8v, but with cams i feel like you could do the same with the S motor but have a much better "race" motor. The S is all 4k+ power. Did that head come with cams and such? whats under the cover?
THAT 195HP....
is that with your current 2.9L or with the old 2.5L?
either way, very nice
That was in a 924 with a 2.5l. The dyno is shown on the Augment website. (They used to have a proper-sized pick on the old website but now it's missing.)
It actually measured 174 rwhp (iirc) while regular S2s are around 190 on the same dyno.
Hence I think my engine shall be a potent one after breaking it in.
Michael I was reading you other comments regarding the flywheel design of the S being favourable for MS. Enticing!
Arominus: NOW FOR THE UGLY: Went in the garage. Didn't take the head apart to check each item, but the loose items showed me basically what I need to know. What do you think?:
Sorry for the crappy camera.
Bent exhaust valves x2:
Chain tensioner... missing something to mount one of the pads, but dunno what that part is:
I cant tell if this is cracked or not from the mounting hold.
ABout 3 of the caps & cam bores have deep scratches or galling, this might be the worst of the damage, I dunno if its re-usable:
Someone toasted this valve cover mount. I can probably fix:
C'mon guys... do you have to be so DARN rough with these aluminum parts?
09-28-2015, 09:25 AM
The logical solution is to drive WOT 100% of the time
