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-   991 GT3, GT3RS, GT2RS and 911R (https://rennlist.com/forums/991-gt3-gt3rs-gt2rs-and-911r-229/)
-   -   2015 Cayman GT4 (https://rennlist.com/forums/991-gt3-gt3rs-gt2rs-and-911r/822961-2015-cayman-gt4.html)

BGB Motorsports 07-15-2014 09:41 AM

I just wish someone would release some specs as opposed it being nothing more than random speculation. Someone like us that builds 3.8L Caymans for sale as new 981 cars has been completely railroaded by these spy shots and this random speculation.

One article says GT3 motor, the other says manual 6-speed transmission and the other says 3.8L turbo flat 6. Maybe...but not likely.

Yet every single person that was all excited to send us a 981 with a 3.8L 991 motor to make a $90K 3.8L Cayman, is now sitting on the fence!!! If you know someone that is looking to get pushed over the edge of the fence, into the BGB yard, the grass is green so please do!

CAlexio 07-15-2014 10:32 AM

This man makes a good point. Great product at great price, temporarily sidelined by our childlike giddiness and gullibility. BGB ftw.

Petevb 07-15-2014 11:21 AM


Originally Posted by Dan39 (Post 11508784)
Very interesting comment, Pete - can you expand on it, perhaps?

We saw that both the 650S and 458 Speciale have double wishbones in the front and the GT3 has Macpherson struts.

The McLaren also has them in the rear while both the Porsche and Ferrari have multi-links.

Is Porsche trying to save us a few pennies here with a non-ideal solution or is it simply the expression of a different philosophy?

I think the front strut suspension on the 911 is mainly a question of money and packaging, but I don't necessarily mean that in a bad way.

There are an infinite number of compromises that go into any car. In the street 911s case the design targets, which include cost, performance, plenty of room for luggage up front, component commonality with the Boxster, etc, have always been achievable with strut front suspension. The GT cars have had slightly different priorities than the base models, and might prefer a different tradeoff given a free hand. What keeps the GT cars affordable, however, is the shared chassis and componentry.

There is no question that double wishbones are the higher performance solution. The RSR, Carrera GT and other bespoke Porsche race cars all use them for this reason. In the RSR, however, a hole is cut in the front tub and a fabricated steel sub-frame and wishbones are added to fit them- certainly not a production solution. A productionized version could be made, but it would undoubtedly be expensive, thus so far Porsche has decided that money is better spent elsewhere...

For the Cayman GT4 the question is doubly important, because the Cayman uses the same strut setup front and rear, and the rear is considerably more sensitive and critical for overall handling. If front double wishbones are nice to have on the RSR they would almost seem required on the rear of a racing Cayman, and I'd be surprised if they release the race car without either that or a multi-link. But will the street car see the same changes? I'd bet against it, but I'd be happy to be wrong.

GrantG 07-15-2014 12:58 PM


Originally Posted by Petevb (Post 11509003)
If front double wishbones are nice to have on the RSR they would almost seem required on the rear of a racing Cayman, and I'd be surprised if they release the race car without either that or a multi-link. But will the street car see the same changes? I'd bet against it, but I'd be happy to be wrong.

I heard that the GT4 received lots of attention on the rear suspension (including GT3-like LSD tuning), but no confirmation if it's only a strengthening and tuning of the existing architecture or a new format altogether.

Petevb 07-15-2014 01:12 PM


Originally Posted by GrantG (Post 11509250)
I heard that the GT4 received lots of attention on the rear suspension (including GT3-like LSD tuning), but no confirmation if it's only a strengthening and tuning of the existing architecture or a new format altogether.

The rear multi-link doesn't package well in the back of the Cayman without extensive changes, so that can't be shared with the GT3 RS. However if the GT3 RS gets double wishbones up front like the RSR then those components probably would fit, and could be repackaged. So we might have a good indication of direction when the RS is revealed.

Previous GT cars have managed to get away with changing only uprights (mainly raising the bearing package to restore kinematics when the car is lowered) plus bushings and arms, so it seems likely that'd be plan A again, but...

CAlexio 07-15-2014 01:42 PM

I stand here to say, that there is NO WAY they are changing the suspension structure to that extent on the gt4... It would become stratospheric in cost for a cayman, likely more than the gt3.

Petevb 07-15-2014 02:09 PM


Originally Posted by CAlexio (Post 11509367)
I stand here to say, that there is NO WAY they are changing the suspension structure to that extent on the gt4... It would become stratospheric in cost for a cayman, likely more than the gt3.

There are some ways to do it that would be cheaper than you might think, especially if they shared parts with the RS. For example Audi, Honda and others have been doing the below for a while, which potentially requires no changes to the chassis and would therefore be much less expensive. It's probably not quite as good as a traditional double A arm setup due to unspring weight, but it'd almost certainly be better than struts and I don't think it would blow the budget- some larger castings and a few more pieces, and remember Honda does all their cars this way.

http://static.ed.edmunds-media.com/u...mb-555x370.jpg

http://static.ed.edmunds-media.com/u...mb-555x353.jpg

http://upload.wikimedia.org/wikipedi...suspension.jpg

BGB Motorsports 07-15-2014 02:35 PM


Originally Posted by CAlexio (Post 11508921)
This man makes a good point. Great product at great price, temporarily sidelined by our childlike giddiness and gullibility. BGB ftw.

God I love you Rennlist types! Such support! Thank you! :cheers:

nh4 07-15-2014 02:42 PM


Originally Posted by BGB Motorsports (Post 11509501)
God I love you Rennlist types! Such support! Thank you! :cheers:

Do you guys have performance stats on your 3.8L Cayman conversions? I had asked on the other GT4 thread that has subsequently died out in favor of this one... Posted below is my original question:


Originally Posted by nh4 (Post 11486069)
Have there been any independent benchmarking tests done with the BGB Motorsports 3.8L Caymans? I did try to dig up some info via Google but not finding much on the actual numbers... I did find plenty of positive comments though!

In particular I'd be interested in an as close to apples-to-apples comparison of the same car / same driver / same track / similar weather showing the delta in 0-60mph, 0-100mph, braking tests from 100-0, 60-0, and time around a circuit before and after the stage 1 work (http://www.teambgb.com/for_build.asp)... Any pointers to something like that?

Thanks,

-nh4.


BGB Motorsports 07-15-2014 02:52 PM

If someone were able to produce a spy shot of that thing in the middle of the corner I could tell you with a fair amount of certainty whether or not it still has the same 991 front suspension turned backwards just like it had the same 997 front suspension in the rear turned around on the previous generation model.

BGB Motorsports 07-15-2014 02:55 PM

1 Attachment(s)

Originally Posted by nh4 (Post 11509520)
Do you guys have performance stats on your 3.8L Cayman conversions? I had asked on the other GT4 thread that has subsequently died out in favor of this one... Posted below is my original question:

Yes sir! Sorry if I had failed to follow up with you. Part of me follows these GT4 threads for obvious reasons and then when the guilt settles in and I feel like a thread troll, I go and hide!

The straight 3.8L 991 transplant results in 350+ rwhp and 275 lb/ft at the tires. This is with the PDK and 6-speed cars. However, the 991 Power Kit motor went into two cars that were 6-speed and those cars are at 375rwhp. The last half a dozen cars dyno'd over 350rwhp but it was usually 2-3 hp. Its 350rwhp but not much more. All cars have manifolds WITH CATS and some sort of muffler, whether it Cargraphic or Porsche Sport Exhaust. All cars had BMC filters BUT NO ECU tuning, no pump gas, no pulleys. I have yet to dyno the 1 car that has the race headers from Cargraphic as it is PDK. The 6-speed cars have an advantage with the buildout given that the PDK is 1 less thing to make my life more complicated. Every day I work towards an ECU file and if the files we had in our 997s can make 30rwhp running pump gas, then I should be able to safely achieve another 10-12 rwhp once I can tune the ECU on this thing. That would be 365rwhp hopefully for a 991 with an aftermarket file, Cargraphic manifolds with CATS, mufflers and filters. This all still includes the factory air intake system, pulleys, etc. I use 12.5% drivetrain loss so per my numbers, these cars all make 400 hp at the crank right now. If you study the 991 motor and its power graph, you will see that while it's quoted at 400hp, it's really a 385hp engine that spikes to 400hp at 7700RPM but makes A TON of torque relative to motors from years past.

Thank you again and to anyone else on here that promotes are little sector. It has been a great way to keep my staff and not have to let anyone go and I am very grateful for any of the leads generated on here or any Porsche forum for that matter. You guys and gals rock!

P.S. Stock motor not broken in on a 100 degree day running 93 octane, no ECU flash and no upgrades but an IPD plenum and a set of manifolds with CATS and stock PSE.

otisdog 07-15-2014 04:22 PM

John, have any of your conversions been registered in California?

BGB Motorsports 07-15-2014 04:31 PM


Originally Posted by otisdog (Post 11509703)
John, have any of your conversions been registered in California?

I have one conversion in NorCal of a 3.4L 987.2 that got an X51 swap, porting, etc. I have other conversions throughout the country in states that have equally stringent smog restrictions. With the exception of 1 car that I am diagnosing in Oregon with what we think might actually be a bad cat, no Check Engine Lights.

I am NOT as versed as others with the OBD restrictions but I think that 1 issue you might run into is this: if tech knows what to look for and plugs into your 981 DME, the firmware number will yield a light bulb. I have NO WAY to get around this.

ChrisF 07-15-2014 08:05 PM

The one nice thing for CA car owners is if you buy, smog and register the donor car first, you have 6 years from date of registration to figure out how to "solve" the problem.

BGB Motorsports 07-15-2014 08:10 PM

"SO YOU'RE TELLING ME THERE'S A CHANCE?!?!"

http://s2.quickmeme.com/img/49/49ded...491650b05f.jpg


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