Racerstev

Agreed, mine is a totally different animal at part throttle and full throttle,
it picks right up when you hit WOT.

By chance do you have the air/fuels between stock and your setup? Mine is
pig rich stock..

Also how is the throttle response and overall drivability compared to stock?

Steve

Rogue_Ant

The 944S/S2 software is setup for emissions & economy as priority #1.
It is very aggressive about keeping the car in closed-loop operation. This means the car stays around 14.7:1 AFR (stoichiometric) for the majority of loads. However, running stoich does not make as much power as a richer mixture. This has a dampening affect on power, making the car feel less crisp when in part-throttle...

A big part of the 944S NA-Tune development was to rewrite parts of the closed-loop operation, to make it a more performance-oriented function. This combined with removing the AFM restriction, the part-throttle power/torque is significantly better! The dyno plot doesn't really do part-throttle operation justice, but it is very noticeable when driving the car.


That is a good question... Really it depends on if Porsche tuned the S2 intake to the same resonance RPMs as they did the S..? If they did not, then some of the tuning we will want to change in order to be as best as possible for that setup.


Interesting - as that is not my experience with the 944S at all... What is the condition of your O2 sensor?

Here is the plots w/ AFR:

Racerstev

The O2 is about 5 months old, and the wideband is fairly new as well. The
problem isn't part throttle, it's stays in closed loop just fine, too fine...

At WOT and higher rpm's it pegs the gauge at 9 to 1, if I drop fuel
pressure down to 47ish from 55 it "only" hits 9.3 to 1.. Also cold start
is super rich till the narrow band heats up.

4-5000 is 11.5 to 1, 5-6 falls into the 10's and 6 to 7 goes into the 9's.


Not sure if mine has been chipped, I can't seem to be able to separate the
2 boards to get to the chip.

Rogue_Ant

Yeah - something is not right with your setup... Once the DME learns the engine, even at WOT i should never be in the 9's (other then, possibly, immediately after a cold-start).

Check out this page for how to separate the boards:

http://www.911chips.com/Chip%20InstallC2.htm

16valver

Kind of funny considering the poor economy of these engines.. I bet your 21st century tech doesn't hurt that one bit!

Interesting. I don't really know what changes would need to be made to the design with .5 more liters and bigger valves. I believe the inner diameter of the runners is the same, but the design is just open inside, which makes me think that the (sort of) spiral design from the S was traded for more flow in the S2. I'll be curious to see what happens when you get an S2 to work on. Though it would be a lot of work for not much info, it'd be cool to see some flow bench numbers on both systems. S2 mani works good with the stock system, but I can't imagine things not getting FUBAR'd with the new tech. We shall see...

Arominus

This may be of interest to you Josh, an S2 dyno plot w/afr on a car running the "firehawk" chip

https://rennlist.com/forums/924-931-...hawk-chip.html

and a few more. Might help you figure out the peaks.

http://www.weissach.net/DynoResults-944S2.html

Rogue_Ant

Thanks for those!

It looks like the S2 intake manifold tuning is very similar to the S...

Arominus

The biggest thing I can see between them is that the internal volume of the intakes increased as 16v development continued. The 968 intake should be the one to show different resonance peaks as it was designed for more low end torque.

https://rennlist.com/forums/5480838-post28.html

Heres a 968 dyno for comparison

https://rennlist.com/forums/9515570-post10.html

Rogue_Ant

Yeah, hard to compare the 968 stuff because of the vario-cam stuff.

Aussie944S

In the words of Jeremy clarkson..... MORE POWER......

This is awesome

Dougs951

Josh- I can vouch for the validity of the firehawk dyno. my car put down almost an identical dyno plot a few years back.

My only complaint is the firehawk tune runs super rich. The dyno plot of the other car must have had either a different tune or a very good cat. With my test pipe you can really tell its rich.

Paulyy

nice going josh!

Walkerhiboost

I need a tune for my S. I am also planning on doing the intake manifold swap which I have in the garage. I am just trying to decide if the stock S throttle body is sufficient and if Megasquirt might be a better option.

Rogue_Ant

That is a tough question... My NA-Tune & Megasquirt are two very different routes to the same goal: more power & better driveability.

If you are the type who wants to completely develop the tune (many times from nearly scratch) for your car, and deal with any issues - then Megasquirt is a great learning tool.
OTOH, if you simply want the ease of plug-n-play and factory reliability, then the NA-Tune is a better option.

jd159

I've got more aggressive cams, headers, full exhaust 2.5 and some 3. No cat. Custom cone intake setup. Competition valve job bigger exhaust valves etc. Quite a bit of headwork!

This winter I'll be bolting up an S2 intake. I have a chip, but its off, mainly because of the different mods I have and having to send the chip out for guestimates.

Would this system get me more power and a more accurate tune even with my mods?