Before I say anything else, let me say this: I think the GT4 is an amazing car and an amazing product—especially at the price point—and well deserving of every accolade it has garnered. Porsche's GT team outdid itself, and I have zero regrets in having stepped up to put a GT4 in the garage. It feels special on every drive, and I find myself lingering a little longer in the garage when I get home.

With that said, 5,500 miles in, and fresh from a back and forth from SF to LA, the gearbox is a real letdown. The gearing problems I noticed at the launch in Portugal are worse than I first thought then, and only get more annoying with more miles. Second gear to 80+ mph? A lot of performance is lost there alone, with the gearing exacerbating the soft low-end and mid-range power of the 3.8 as set up in the GT4. Third gear is too tall, too. Conversely, bizarrely, sixth gear is too short. On the 5, I looked down at the tach at least a dozen times to confirm that I was, in fact, in sixth gear. The 3.8 was turning 3200-3500 in sixth where its torque would easily carry the car nicely at, say, 2500-2700. I didn't even need to downshift from sixth while climbing the Grapevine, a hill so steep trucks are reduced to 15-35 mph. Result? Even with a 17-gallon tank, the GT4 requires a gas stop on a drive where a 991-1S doesn't.

Perhaps the GT4's shift **** should say:

2 4 5
3 5 5

It's also a pity because the GT4's linkage is Porsche's best yet—there just isn't much reason to actually use it. The team that developed that linkage as well as the rest of the car nodded when I mentioned the ratios in Portugal—the project's budget meant a new gearbox or custom ratios weren't in the cards. I'd say they spent the money they did have well, but I can't think of any modern Porsche so hampered by its gear ratios.

Of course, this creates a tremendous opportunity for an aftermarket company. My take is that the GT4 would wake up with 1st through 5th from the 991-1S transmission, and 7th from the 991-1S as a sixth gear for cruising. Or maybe even something a bit more aggressive in ratios 1-5. The GT4 would be transformed in terms of low-speed performance, probably closing a lot of the performance gap to 991 GT3s at many tracks and in various timed tests. Out in the real world, in terms of driving satisfaction and fun, it would also get through the soft sections of its power band more readily. It would also be more fuel efficient and more relaxing on the freeway. Yes, if you're driving a GT4, you can afford the gas—but wasting fuel on the freeway is kinda dumb, as is turning a lot of revs for no benefit. It's just more noise, and engine wear.

I have suspect a revised gear set won't be cheap, but I wonder if there is a way to simply bring over 1-5 and 7 from the 991-1S MT or 981-1 PDK gearbox? I know it's a different case, but the gears, at least, exist. It's a worthwhile project, as this is a rare Porsche where I'd put new gears in well before turning to engine mods. Of course, the right gears plus better breathing and a linear power band? Well, that would be heavenly...

 

Gears 3,4,5 and 6th are available from GT Gears...also there's a European company doing R&P but not much info on that. Check out Sharkwerks latest posts. Their GT4 has 3-4-5 from GT Gears plus the lightweight flywheel.

 

Pete - I totally agree with you, with the exception of your opinion about 6th gear. The GT4 is a performance car and it is geared perfectly in 6th gear to reach Vmax (183 mph) at the peak power point of 7,400 rpm. In Germany, it feels awesome on the Autobahn in 6th (if not the most relaxing). Would be a shame to trade performance in 6th for more quiet and tranquility, just as it is a shame to give away so much performance in 2nd through 5th gears in the name of fuel economy, emissions, and budget dollars.

 

4th gear in my other car tops out at 105 mph or so, hah!

I am fine leaving 6th gear alone. I can get up to 23 mpg on the freeway and that is good enough for me. Rest of gears def could be shorter. Though the long 2nd has some advantages on the right road, but would still prefer a lower set.

 

The problem is no one has addressed the too-tall 2nd and the too-short 6th. It isn't an easy solution, or a cheap one. And it's a risk: Will the customers materialize? However, I think the payoff will be such that they would, as I suspect the right set of gears would transform the GT4, helping it make the same leap an E30 M3 does when you go to the 2.5. It ain't cheap, but suddenly a so-so engine in an amazing chassis is both faster and, interestingly, far more enjoyable in use.

I drove the Sharkwerks car, and love those guys—and also respect the positive opinions of Mooty, Ralph, and Catchpole—but I feel that setup might be okay for track work but isn't so great for a street car. Nor does it fix the too-short sixth gear. I did like the new third and fourth from GT—a lot—on back roads, but the new third is VERY close to second gear. On one downshift to second, I pushed the clutch back in before letting it out all the way because I thought I'd missed the shift—so close were the revs in second to the revs we'd been at in third. Nope, that's just the way it is. It's a compromise, because a new 2nd gear isn't gonna be cheap. In a track car, maybe that won't matter. I can't see a lot of street customers being happy with it. YMMV. The LWF is brilliant in the Sharkwerks GT4, as is the upgraded GT diff.

I could see a new R&P with an extra tall sixth gear working out, but not sure if the 991-1S 7th would be tall enough once the R&P is lowered, however.

To me, the first company to figure out how to put 1-5 and 7 from a 991-1S or maybe the same set of gears with advantages from a PDK box into the 981 GT4 transmission will unlock the car's real performance capabilities, increase the fun factor, and improve comfort/driveability too.

 

Fair feedback on others' views on 6th gear. I might feel differently if I lived near the autobahn, or someplace I would actually see 183 mph, but I'd make the trade in a heartbeat here in CA.

183 mph is mythical, and really not that interesting to me having driven at those speeds and beyond quite a bit. I'd rather be more comfortable on long hauls to crazy good 2nd/3rd/4th gear roads or tracks.

 

OP, I agree. I would be interested in a gearbox exchange where 1st was taller, 2/3/4/5 shorter, and 6th taller. Or a 7 speed with the same 6th and a 7th that would give me 2,500 RPM at 75 MPH. I don't care about the MPG so much, it's just that when I want a relaxing cruise, I want a relaxing cruise. Sometimes I want that in the GT4.

 

I agree with you. I love driving the car, I love sitting in the car, and I love looking at the car. I wish it had more power down low...it feels like sacrilege to admit it, but maybe afuture 718 GT4 will be our car WITH gearing to match its turbo four. However, a flat-six to me is a unique proposition, something that a turbo four-cylinder, no matter how special, isn't.

Why not contact Preuninger? I realize that might sound ridiculous, but the OP has connections and might be able to ask his opinion and potentially get some answers. I bet that if they felt the first six gears from the 991.1 S would work better, they would have done it, but who knows with certainty. Mr. P seems very forthright and might be able to answer our questions directly.

 

I'm die-hard NA 6 cyl., no turbo or 4 for me, thank you.

 

Pete, your concerns are one of the major factors why I cancelled my allocation and did not purchase a GT4. That 2nd gear does the car no favours, especially for street use, which would have been my focus. That combined with a conventional non-GT engine, low steering feel, and hampered rear visibility pretty well sealed the decision for me.

A change of gearing would make the car come alive, but imagine that combined with a GT3 engine in this car -- now that would be magic!

Oh god, now I am going to get flamed...

Cheers,

Mike

 

The engine character and steering precision are tremendous on the GT4. Rear visibility doesn't matter if you're passing everyone. You missed out!

 

I agree that the gears could be better, however, I don't think they are very far off actually. I'm also not sure a lot of performance is lost in the real world, which can be worked out. Because the torque falls off steadily above 6.5k rpm, the power (the important metric that determines when you shift) at the fuel cut-off, 7800 rpm, is about the same as 5400 rpm. So that gives you 2400 rpm to work with. The stock rpm drops are

1->2 3165
2->3 2147
3->4 1548
4->5 1239
5->6 1147

So one could argue that the car drops to 4500 rpm in 2nd after shifting from 1st so a tiny bit of oomph is lost, but a gear change takes time so I'm not sure if anything is actually lost on the clock for a run to 80, which with a shorter 2nd would need a shift to 3rd. Also, on most tracks 2nd isn't used that often and I don't think there are many corners that would benefit from a shorter 2nd.

The 2->3 change with stock gears should be done close to redline because the 2147 rpm drop is close to the powerband range of 2400 rpm. So 3rd could be a tiny bit shorter compared to 2nd, but the optimal gap is very close to what the car already has. The 3-4 change can actually be short shifted slightly without losing time because 3 and 4 are already close enough together


I disagree here. I buy a GT car because it shouldn't be compromised wrt to the gearbox. There is no performance reason to have a top gear that cruises at 2700 rpm at 85 mph on the highway. The GT4 is at 3340 rpm at this speed, which is quite relaxed in my experience. I want all my gears to be logically spaced with regard to the total performance capability of the car which means that top gear should match the top speed, not higher. 1st should be as tall as possible without making parking lots difficult (a tall first means less gap to 2nd and closer gears all the way through, plus 1st might actually be useful on incredibly sharp turns on mountain roads). 2-5 should be gapped appropriately in between. This is how the GT4 is geared already. There exist some tracks with banked sections where 6th might be needed and with an overdrive 6th the 5-6 gear change would be embarrassingly awkward. A 1998 CR-V in 5th on the highway is buzzy, it's like 5 is 4. To me the GT4 is calm and quiet without feeling like I turned the engine off just because I'm in top gear (thinking some corvette models).

The car may feel more punchy, but seeing the analysis above taking into account the powerband, I don't see any difference against the clock with a gearbox change. I don't think Porsche went with the stock ratios because they'd hurt performance, calculations show they don't However, if the top end was freed up with an X51 package, THEN a gear change could help take advantage of that.

My perfect gearset would be:
gear / top speed at redline / rpm drop to next gear
1 48 2816
2 76 1990
3 103 1548
4 128 1241
5 153 1224
6 181

(and sure if a 7th could be added without a durability/weight/feel hit, why not?)

it's not very different compared to stock gearset:
gear / top speed at redline / rpm drop to next gear
1 48 3165
2 82 2147
3 114 1548
4 142 1239
5 169 1147
6 198

 

Pete, I have to agree with you I wasn't pleased with the GT4 when you and Torsten brought it up a me to drive a couple months ago the gearing and lack of throttle response was disappointing to say the least! It was boring and lacked personality, I think you need to give the Sharkwerks car another drive. I don't know at what stage the car was when you drove it, I do know that it now has headers, a bypass, LWF, a new LSD, a great tune along with being fitted with a GT3 intake! There is now plenty of trq and throttle response which coupled with the mid-engine platform makes it very nimble and fun to throw around my roads and it's very easy to drive in city traffic such as 19th Ave which I have driven on several occasions. You are very aware of my my roads and driving style, which I feel is similar to yours, so you are aware that I know what I'm doing and what I expect a car to do. This is by far the best mid-engine Porsche car I've ever driven and it's night and day different from a stock GT4 After James finishes what he's doing with my 100,000 mile 3.9 you should grab Alex and come up for some driving After which we can compare opinions, just my two cents.

 

A lot of us were saying this about the gearing in the beginning but were dismissed.

The USDM NSX 5spd had horrible gearing and years later the gear swaps have been plentiful and transformational.

 

After switching from the 6 speed in my BMW to the GT4 the difference in ratios was pretty dramatic. the long 2-4 gears really dull what I think is actually a pretty great motor. If 1 and 2 can't be changed maybe a 15-20% shorter final drive and longer 5 and 6 might be a good compromise?