sticky

Cool story.

So provide the data showing //methods dyno is inaccurate as you claim.

Provide the data that shows Porsche does not underrate the 991.2.

Provide the data that matches any of your claims.

Thus far I have provided data that supplements my statements. You have provided opinion.

Maybe it's time to read about how dynos differ?

Since you likely won't I will point out to you an E92 M3 dynos 350 wheel on a Dynojet. Our friend Quattro put down 35X wheel with his 991.2 on a Dynojet. The E92 M3 is rated at 414 hp. The 991.2 base at 370.

Would you explain why all data supports me and not you?

randr

Sticky, its called integration - or calculus if you prefer. Its a standard and very simple mathematical approach.

You will find Porsche engineers do similar calculations to determine where optimal PDK shift points should be placed in order to deliver maximum power under the curve - essential for race strategy.

I have given you an accurate and exact explanation for why the 991.1 GTS and 991.2 base deliver similar performance. I did the calculations and delivered the answers and the explanation which is remarkably straightforward.

That explanation is, between 4000rpm and the redline, for both vehicles, the difference in HP the engines actually deliver is about 10HP (~340HP for the 991.1 GTS and ~330HP for the 991.2 base.

Therefore, and as a consequence of this small difference, they perform in nearly identical fashion.

That's why understanding power delivered under the curve is important and peak HP is somewhat irrelevant.

P-car fan

Good grief you two quit highjacking the thread!

To the OP: Are the O2 spacers continuing to eliminate any CEL's? How's the exhaust smell without the cats?

BlazinPond

I purchased these from the OP, so I will pick this question up for him.

I had the pipes w/ O2 spacers installed on my new GTS along with a new Akrapovic slip on. Actually, my dealer installed the first week I had the car.

I've had two CELs during the first 200 miles. After the dealer read the first one, they reset it. It then came back after another 100 miles.
Strange though, the last CEL went away on it's own after about 5 starts of the vehicle. I wasn't expecting that!

___

As far as the exhaust smell, it really doesn't bother me and I don't smell it unless I am letting the car warm up in the garage.
Then, it is a bit obvious w/ exhaust.

///M3THOD

The smell isn't bad, if your familiar with what it does smell like.

I just didn't care for it in my DD in heavy traffic. I no longer have the car, but I never experienced a CEL with my C2S.

The gentlemen I sold them to has a GTS and he contacted me recently asking me about any CEL issues. I'm hoping he'll respond in this thread.

Im going to run sport cats on my new car. Unless I see that they are extremely restrictive once tuned, which they may be, considering the sport cats on the market are interchangeable between the Base, S and GTS variations even though their outputs probably will vary considerably once tuned.

///M3THOD

You got this in before I could even post about you potentially posting!

What did Fabspeed say? How many miles were on the car before you installed also? Is the CELl off now?

P-car fan

Thanks!
I'd really like cat bypass pipes for the sound, but still hesitant because of what can come with them regarding the CEL and possibly needing a tune to account for them

BlazinPond

Lol.
I didn't call Fabspeed (Yet) because the 2nd CEL went away on it's own.
I'll play it out a touch longer since it's so new.

I put 40 miles on the car before my dealer changed up the exhaust system.
I think it had 50 miles total on the odometer when the actual work was done.

I have 600 miles total now.

Churchill

A before and after dyno run using two different cars on two dynos is completely useless. Actually worse -- counterproductive, because there are a bunch of people who don't understand how this stuff works and will mistakenly think that the before/after results have merit.

windblow

How does the cat bypass with Akrapovic sound compared to stock GTS? Are you happy with this set up?

BlazinPond

I love the setup.
As long as the Check engine light stays off or is VERY infrequent.

With valves closed, it's wife approved...meaning it's not overly loud and obnoxious other than cold start up.
With valves open, I believe it meets or exceeds any stock 991.1 n/a (IMO).

tango131

THIS!!! After reading pages and pages of this back and forth silliness between children and a few adults. THIS. Darn it.

If OP trying to claim that his mods increased power from the Cobb dyno numbers to his/her dyno numbers, well that’s just plain silly (or wrong, inaccurate, baseless, etc whatever anyone wants to call it). It’s like comparing apples and pineapples. Yes they are both fruit, but very different and unrelated kinds of fruit.

Only way to know what the gains are, is to take the average of several dyno runs pre mods, and compare them to an average of several runs after mods on the same dyno same day (with ideally same gas, humidity, air temps, etc). Even two back to back runs on same dyno have a certain (small) percentage of error, hence why you use average of more then one run for baseline and for after mods results. Otherwise completely useless. And that’s the end of it.