While doing my testing over the past few weeks, I was really surprised that swapping out the stock AP2 exhaust with my customized AP2 exhaust with Magnaflow mufflers made no change to anything. It didn't even make a 0.1 change to AFR. Aside from the test pipe and Magnaflow mufflers, the rest of my exhaust was totally stock. As you can see above, my car made more power than the other FlashPro'ed AP2s that had 70mm exhausts.

 

The OEM exhaust flows well.

I think Mase came to the same conclusion as you with the turbo cars. He was going to make and sell a custom exhaust and decided that there was no benefit over oem. Obviously a different application, but same result.

 

It flows well considering that it's an OEM single into dual exhaust. It doesn't even compare to a 3" manifold back single though

Everything after the collector is a restriction.

 

"Here is another plot from an "S2000 club dyno day" a couple weeks ago. My car just had a test pipe, PWJDM intake, larger injectors, and a custom FlashPro tune. The 2 AP2's under mine each had a CAI, Header, TP, and 70mm exhausts."

Why would you need larger injectors???? My tuner said it would be a waste of money. Im looking for da troof!!

 

My injector duty cycles were hitting 95%, which seemed excessive. I figured I would upgrade to larger injectors for reliability, and also to try out E85. I was surprised that I gained power from them, but I did. I guess the spray pattern is better. Or maybe the fuel atomizes better when duty cycles are only 45%.

 

my car was different. Comparing logs and data when I had the stock exhaust vs the litespec 70mm exhaust, there was significant gains.

 

When did you finally make the switch? What injectors did you go with?

 

It's been a few months since I istalled them. I got Siemens Deka 630's. I started 1 or 2 threads about the injectors and E85.

 

Those are great results considering the minimal
"bolt-on"!

I'm considering a program from a tuner........
1). custom fab header
2). custom fab test-pipe
3). K N filter
4). flashpro tune
5). dyno tune/paperwork etc.

Shows AP2 at 236whp and 170lb.ft. which are higher than
the results of your car....this tune I would reach "stock"
AP2 max HP at 6200rpm and "stock" max torque at 3500.

Of course your low-end torque numbers are awesome and match
this program's they along with HP just don't top out as high.

I'm still consideroing the cost to play.....$1800. tune etc.
of just get 4.44 gears built/installed for $1300.

Of course together they would be great but I'd rather go one
or the other and use cash for CR springs/sways/dampers

 

ps...the tuner told me there was really nothing to gain from
exhaust change in regards to performance....unless your goal
is to change the sound of your S or to reduce some weight
considering the OEM exhaust is (relatively)heavy.