GTgears

Two of our kits actually only change 3-5. Even with the 3.8 how many are going over 160mph at a DE? So we pull them in while leaving your highway 6th intact. I've done a couple for nor cal guys and even with our shortest stack they will never see 6th at the LS,SP, TH trifecta. So we are just those as 3 gears kits even on racecars.

DeerHunter

The problem, as I see it, is that changing 3rd gear and up only affects you at speeds well north of 80 mph. Even on the most remote back roads, this is pretty quick. I know the issue is the mainshaft with gears one and two, but I think the only way to improve gearing for real-world use is to tighten gears 2 through 5. Maybe one day a solution will become available.

jphughan

Well perhaps I'm in the minority, but I don't redline every shift on back roads, so I don't think the tall 2nd gear will be as much of a wet blanket as some people fear. Check out this table showing approximate speeds in various gears at various rev ranges given this car's gearing and tire size. As you can see, if you short shift even by 1000-1500 RPM, which I'd probably do off-track fairly regularly anyway just out of mechanical sympathy, then the gearing starts to look somewhat reasonable even for back roads.

IMOA

On a backroad you don't have to be bouncing off the rev limiter though so for a corner which is taken at around 60-70mph while you could use 2nd as long as 3rd isn't too tall then that would be fine. I do also kinda like the long second though as it's a very usable gear for tight hairpins at the track as it should get you to the exit before needing to shift. There are very few corners on a racetrack where a 2nd gear which is good for ~65mph can be used for.

The change 3-5 keeping 6th as a highway cruising gear seems a very good option to me, I think 2nd will end up being a lot more effective than people think and if there is a real problem it's further up the box

GrantG

Deleted

DeerHunter

Well, we're all bench racing at the moment. Let's reconvene later this year and compare notes.

Crazy Eddie

GTgears

Well... Not everyone. BGB, and about a dozen shops have already built 3.8 powered caymans. They have been running around the streets and tracks of this country for a couple years now. This car keeps getting treated like it is all new territory. It isn't.

We raced a whole season of Rolex with BGB in a 3.8 car while we developed our gears. Eric Oviatt and Duane out in CA have been battling in POC for several years in a swapped Boxster and cayman, respectively. And there are plenty others. This really isn't as uncharted as threads like this one make it seem.

jphughan

Fair point, but gear ratio expectations are much higher in racing applications than in road and DE applications. Are there are any 3.8 swap owners around here who would care to offer their impressions of how the stock gearing suits this motor while on back roads and at DEs on various tracks?

GTgears

I think BGB said they did 11 swaps last year. I am sure not all of those were racers. Hopefully one or two of them are around and can chime in. I think one guy posts down in the 987 forum. Maybe someone can ping him and ask for his opinion.

stout

Driven by EPA/Euro regs.

I'll be curious to watch GT4 owner/leasee sentiment in the months and years to come. The GT4 is a brilliant road and DE car, and I think people are going to be thrilled with it. Period. The stock gears may work out okay for many tracks, but we'll see. But, after driving the GT4 on track (where the gearing didn't bother me) and on canyon roads (where it did), I felt the gears that want attention are either 1-5 or 2-5. Starting with 3rd won't solve that primary speed-in-gears problem. I like to see the upper reaches of a tach from time to time, and 81 mph is awfully fast in 2nd, and it takes longer to get there than it would with a lower gear. 6th could stay the same or actually go taller to get revs under 3000 at 75-80 mph.

I suspect the first aftermarket company to come up with a rock-solid fix for $3-5k will be a darling of GT4 (and S and GTS) customers—but it's easy to say that when I'm not betting my livelihood on it.

pete

neanicu

Well said Pete as always!

Having driven PDK Porsches and seeing how the gearbox gets you in 7th at 35MPH,I can understand why Porsche thought that having a long second gear will help achieve good numbers in a manual.
For ex,as I said before,I like to shift. So on the street I won't be able to rev the engine close to redline in second,not if I want to keep my license. So I'll shift to 3rd right away,even 4th. Without having driven the GT4,I suspect it's designed to not bog down,even if you shift too soon. Objective accomplished for Porsche,along keeping costs down for using the parts bin special GTS box. Also leaving room to shorten gears in the RS and not stepping on the 911s GT toes.
Very well orchestrated plan!

GrantG

The problem with making 6th effectively any taller is that Vmax will be reduced. Of course adding a lower R&P without addressing individual gears would also have the same effect (with rpm's rising instead of falling). The current 6th gear was chosen so the car's terminal velocity happens at the peak hp of ~7,400 rpm. Not that it matters much stateside...

In the 997.2 RS, Porsche used a lower R&P and then made 6th gear taller to compensate (and maintain Vmax). While one of the more expensive ways to achieve a result, it seems pretty effective.

stout

The point in bold. I'd want the revs to rise. A lot. And I'd want to get through 2nd and 3rd sooner. (Second, iirc, felt fast; third got a little long in the tooth between 6000 and 7800 rpm...like what are we waiting for?).

Which is why shorter 1-5 or 2-5 and an effectively taller 6th is what I think I'd want after driving the car. But I think the best advice came much earlier—Spend time with the car and see. One thing about the current stack that may be seen as an advantage to some is the fact you can "choose your own adventure" on back roads, with flexibility in gearing and torque to scream along in second or go a gear up to third and flow. The 3.8 can certainly carry third in the GT4.

pete

GrantG

We're definitely on the same page, Pete I was only making the point that the current 6th gear actually has a performance rationale, while the other ratios do not.