jphughan

From the gear ratios thread:

Of course BGB pulled this off in a standard 981 body, whereas Porsche had (and took) the opportunity to change the body in white for the GT4 since AP claimed that the 991S motor didn't fit at first, so maybe they could have done it even more easily than BGB and offered the Powerkit at least as an option. And maybe they didn't because it involved some tradeoff that Porsche didn't feel would be acceptable on an OEM car or because they were targeting a certain price point. Remember, Porsche (so they claim) was genuinely worried that this car wouldn't sell, so I suspect they felt they would need to keep their costs down in expectation of having to price it to sell. Of course that's not at all how it worked out, but hindsight and all. Anyhow, given what the Powerkit costs, I for one am glad that they at least didn't make it standard.

neanicu

I am glad we're on the same page finally!

I'm suspecting the reason they didn't do it,besides cost,it's so they can have a power bump for the RS...

GrantG

Yep, and if the RS is PDK only with powerkit I'd rather have GT4 (independent of price).

neanicu

For sure!

Although,IMO it will be Manual as well. I would've said that there's a possibility PDK can be offered as an option,but seeing Porsche's latest trend with the small GT department,they probably won't go through the trouble of offering 2 drivetrains...

jphughan

Well I'm just speculating here. I could also imagine them not doing it because it would have decreased cabin space above the motor to the point that even more GT4-specific parts would need to be created and rear visibility would become even worse (possibly running afoul of regulations somewhere in the world?), or maybe the solution just aesthetically isn't pretty. I've never seen an X51 conversion in-person, and BGB is perfectly understandably reluctant to go into too much detail on how they work their magic, so it's hard to even make educated guesses about why Porsche didn't do what BGB managed. But it should be obvious that aftermarket companies like BGB offering tailor-made conversions have far more flexibility and far fewer regulatory considerations to deal with than OEMs building cars for several world markets designed to appeal to a larger customer base using factory assembly lines that have already been tooled up. For example, I remember reading an article on the new RS where AP said that the 21" wheels were a huge production problem because the slats that run alongside the assembly lines where the wheels are held until they're mounted would only fit 20" wheels, so Porsche spent a hideous amount of money widening those slats to accommodate 21s (likely because they knew future cars would use them). Of course that wouldn't be an issue with BGB, and in fact it wasn't an issue for Porsche on the 918 since it had a completely separate assembly process, but I just bring it up as an example that just because something is possible for an aftermarket company doesn't mean it's possible (or at least feasibly so) for the factory. Factories get to realize economy of scale that the aftermarket doesn't, but they also have to swallow much higher upfront costs to get there, and sometimes those numbers just don't add up, in which case they may well decide to work within the constraints of what they already have.

GrantG

I figured a small power bump and the addition of PDK-S would give the necessary differentiation from the GT4. I agree that just one gearbox is likely but I guess I was assuming it would be PDK and not manual.

If the final figures are ~415hp with 7-speed PDK-S (top speed in 7th gear near peak power of 7,500rpm), I think this car will give the 991.1 GT3 a pretty good chase at most shorter tracks. I guess with the 991.2 GT3 coming soon with ~495hp this should maintain a gap...

neanicu

You may very well be correct.

We're just speculating anyway...Porsche won't even admit there's an RS coming,so all bets are off...

BGB Motorsports

The only reason I'm chiming in is to address things that I don't agree with; while cost may have been a reason, I don't think it's to create a hole for an RS model. The new coolant fill expansion tank is the reason the manifold doesn't fit. Porsche didn't do it to fool anyone; it would have required a total re-engineering of the engine bay and how the coolant is added from the fill hole next to the LR shock tower. It requires hours of grinding and fitting and each and every time the customers were made aware of what was required and we did what was asked of us. It's not rocket surgery...it just wasn't plug n play and not possible at the time. The motor is the same exact height as the 3.4L. That's the scoop. There you go.

FrstPorsche

It's funny how everyone thinks there is always some sort of publicity stunt going on when Porsche announces a reason for something. Could they make it fit like you have? Sure. Do it on a mass produced car that needs to roll out soon? No. That being said I'm sure they are working on a way to make it fit and some other tweaks for a possible RS version to follow later. They know if they make it we will buy it and with even more frenzy than the current gt4.

Da Hapa

Awesome! Thank you for chiming in and again, thanks for what you do for the community.

I'm curious if you have any input on my other questions about CARB certification, etc.?

Thanks.

otisdog

Honestly, given the level of competence I've observed at CARB test sites, and the fact that you can't even see the motor on a Cayman, I don't envision having any difficulty passing a visual inspection.

Da Hapa

It's not the visual inspection that I'm worried about. There's no way anyone can see the filters, for example. But I believe, and please correct me if I'm wrong, that aftermarket cats normally do not pass the State's sniff test. I don't know how the ECU tuning would affect that.

GTgears

That is correct, most do not. However, the beauty of brand new cars is that you have a handful of years before you need to worry about it. Even with testing every other year after the initial grace period, swapping exhaust isn't a major deal. I do that on two of my cars. Takes me about an hour before the test and an hour a day or two later to put my headers back on my cars.

BGB Motorsports

We need to find other west coast members on here with aftermarket cats to ask so I'm not guessing or making inferences. You are welcome by the way and thanks for the compliments.

We aren't trying to spook anyone with the things we do; I don't know what it is but folks always ask us for some extreme projects. The whole rear intake scoop thing is another one. And yes, I bought that thing on a web site in California that sells carbon fiber Subaru WRX parts. We have just spent so much time without any Cayman support the only thing we know to rely on is the "old college try!"

Phokaioglaukos

How are you attaching the sub belts?

No chassis modifications is great? How about cosmetic modifications?