neanicu

AP has mentioned a few things when grilled by journos about the long gears. Besides the obvious cost savings when using the 981 GTS box(which AP didn't get into further because of fear they'll be accused of using the parts bin) :
-He said the box was optimized for the Autobahn-long gears don't matter there when you can reach unlimited speeds.
-He hinted that the box is " safer " when it comes to money downshifts-it's obvious with longer gears.
-He also said these gear ratios are " safer " for the increased torque.

With all that said,many points being made here refer to the track,but people tend to forget this is a street car first and foremost...a street car that can be used on the track. It's not a racecar no matter how much Kool-Aid is being consumed. For a street car,when going on twisty winding roads and the speed limit is 55 MPH in the best case scenario,most are lower...a driver wants to shift. And if you shift like it is being suggested here(at redline each time),2nd gear will get you to 82 MPH!!!! That's almost 30 MPH over the speed limit!!! In some states that's jail and confiscation of your car. So you can basically approach every and any driving road in 2nd gear and not have to ever shift. That's like having an automatic transmission. Now I've adapted to this and certainly do not have to shift at redline each time to enjoy the car,so I wouldn't risk losing the warranty by changing the gears for that alone,but I understand the complaint.
It's still a great car IMO...

stout

Just really well summed up.

And yes, it still IS a great car.

Alan C.

Nick

Beantown Kman

^^^ Yup! neanicu hit the nail squarely on the head.

mark kibort

As far as gear box comparisons with the 911S , the GT3, GT3RS, and the GT4 cayman…. I put some comparisons down last night thought I would leave you all with some data points.

Someone suggested I put some of the gear ratios down for comparison so they can be found in one place. As you can see, vs the 911, the GT4 has more optimal gears with a closer ratio 12.8:1 for 1st gear is a pretty deep geared 1st, and it has the same spread as the 911 (actually a bit better). After that , it has a closer 2nd to 3rd. but a farther 3rd to 4th…. Then, it has a closer 4th to 5th and 5th to 6th, with NO 7th. So, you don’t get the 2.4:1 super highway overdrive gear with the GT4, but 3.15 :1 for a car with a 7800rpm redline is pretty standard.

The point here is, 3rd gear and higher, you get better than .78% of max RPM post shift.. this means you are always in your max HP zone.. you cant improve that for max forces to the rear wheel, in ANY gear at any same speed. BUT, I understand the comments about wanting to shift more. Heck, I have a street car with the same 2nd gear as well. But its easy to shift , even in spririted driving, into 3rd by short shifting around town. Shifting at 6k, is not lugging , by any measure. Plus, as someone said, you get arrested by going 80mph around town ……… you certainly get arrested by going WOT for more than a second or two as well…. I don’t see the need to change 2nd for that reason and all other gears look perfectly suited for all uses, street and track.

By the way, I put the aston martin vantage below at the bottom for a comparison……….look familiar?? Redline is 7700rpm too.

Just thought a second set of eyes on the subject might create a little different vantage point and perspective.

Hope it helps.

For reference though, the 2008 GT3 RS has pretty close gear ratios.
GT4 gear ratios vs GT3RS 1st through 6th and then vs the 991S
GT4 GT3RS 911S
12.8 vs 13.1 vs 13.45 1st gear 59% of redline RPM post shift for GT4 vs 58% for 911. GT4 has closer gears 1st to 2nd (small diff)
7.6 vs 7.7 vs 7.87 2nd gear 72% of redline RPM post shift for GT4 vs 67% for 911. GT4 has closer gears 2nd to 3rd
5.5 vs 5.6 vs 5.33 3rd gear 78% vs 83% 911 is closer (3rd to 4th)
4.3 vs 4.4 vs 4.47 4th gear 86% vs 82%.. GT4 is closer (4th to 5th)
3.7 vs 3.6 vs 3.71 5th gear 85% vs .81% GT4 is closer (5th to 6th)
3.15 vs 3.16 vs 3.02 6th gear
2.44

The big difference is the RPM ranges of the engines 7700rpm vs 9000

I think the GT3 looks like this with Redline vs top speed in gear
1st = 49 MPH
2nd = 82 MPH
3rd = 113 MPH
4th = 144 MPH
5th = 183 MPH
6th = Top speed

for reference regarding:

2010 GT3RS / 2010 GT3 / 2008 GT3RS

Gear Ratio ----------- GT3/RS 20008/2010 ------------------- GT3RS 2010
1st gear 3.82 3.82 3.82 total ratio 13.1 ------------------- 14.85
2nd gear 2.26 2.26 2.26 total rato 7.77 ------------------- 8.79
3rd gear 1.64 1.64 1.64 total ratio 5.64 ------------------- 6.37
4th gear 1.29 1.29 1.29 total ratio 4.4 ------------------- 5.02
5th gear 1.06 1.06 1.06 total ratio 3.6 ------------------- 4.12
6th gear 0.88 0.92 0.92 total ratio 3.16 ------------------- 3.42
Reverse 2.86 2.86 2.86

Final Drive Ratio 3.89 3.44 3.44

For comparison: the racing and street aston martin vantage : look familiar? Yet no one on the street or the race track is looking to alter it. the big difference.. as some mentioned on the thread and my persona pet peeve… hyway over drive gear
12.2 1st
7.7 2nd
5.6 3rd
4.47 4th
3.64 5th
2.34 6th

d00d

So much talk here, buy one of those orphaned 2.7L transmissions, modify with LW FW and Guard LSD, drive!

mark kibort

It seems all that does is give you a REALLY short 1st gear (14.2:1) and then you stilll have the big jump to 2nd, same as before, yet the 2nd gear redline speed is 78mph vs 82mph.... is that the solution to the problem or creating another one with more hyway noise due to 4% higher 6th gear RPM?

by the way, are the new GT4 gear boxes any stronger, because its newer technology too? just curious? (better synchros, etc?)

cayman 2.7
Gear Cayman

1..... 3.67 ..... total gear ratio 14.26 really short 1st
2 ..... 2.05 .........8:1
3 ..... 1.46 ..... 5.67
4 ..... 1.13 ..... 4.39
5 ..... .97 ..... 3.77
6 ..... .84 ..... 3.26

Final drive is 3.89

d00d

The GT4 gearbox has larger CV joint flanges that need to be swapped into the new one, can't buy them separately.
Other than that there are probably no differences, it's parts bin engineering.
Higher final drive and Guard 3-4-5 are the other options we have at this point.

GTgears

But you already have those flanges on your car.
The one thing we don't know about the 2.7 gearbox is how the 3rd gear is made and whether it risks the failures we are seeing on the GT4. Given that we've been racing them in IMSA Continental Tire ST class for several years and aren't seeing failure, my inclination is that the 2.7 3rd gear is still splined like 987.2S gearboxes were.

I sent Pete my thoughts on a 1-5 set up last night. I am sure he will share them once he digests a bit.

Accel Junky

Perfectly stated.

I also don't think the 2.7 gearbox is short enough. It is still 78 in 2nd. Some of the best cars I've driven have had really short gearing. Usually 2nd topping out around high 50s to 60-62mph.

My Fiesta has really short gears. Doesn't even hit 60 in 2nd but it is a riot to drive on the street AND the track. I don't care about the lap times enough to worry about time lost shifting. Banging gears is why I have this hobby.

GTgears

You can blame magazine tests for the stupid short 2nd on so many cars for so long. 0-60 and 0-100k tests became so important in marketing that they built the cars like that at the expense of 60-120mph performance. This is actually an example of Mark's gibberish about moving around where it performs best makes total sense.

My Subaru is the same way. 1998 they gave the car a 6500rpm redline and it went to 60. 1999-2004 they dialed it back to 6250 because of some engine changes and now they go 58mph in 2nd. Even on some auto-x courses I have to use 3rd. TOO short. IMO a perfect street rod 2nd gear goes to 68-72mph.

d00d

Yeah, but would prefer buying another set of GT4 flanges so I could leave the original transmission unopened.
It would be great if 3rd is splined in the 2.7L.

GTgears

You don't open the gearbox to remove an axle flange. Takes 30 seconds with a pry bar or slide hammer. Held in with circlips.

Personally, If I had one of these cars, I would only consider the 2.7 option if I was going to regear 3 and up. That 1.48 3rd still isn't short enough. You're still looking at a 2-3 shift that barely gets you about 5000rpm going into 3rd.

GTgears

Imma just leave this here...
https://rennlist.com/forums/993-foru...t-and-2nd.html

mark kibort

looks like the 2nd to 3rd gear shift in the 2.7 vs the GT4 is stilll 5650RPM which is the beginnng of the highest HP range. (where did you get 1.48:1 2nd to 3rd gives 5000rpm?. 1.48 / 2.05 is .72 x 7800= 5600 --------thats the RPM drop of the 2.7 from 2nd to 3rd gear shift )

dont know why you would want to change that, unless you wanted to sacrifice a little bit of the closeness of the 3rd to 4th shift, by making 3rd shorter ....... less usable in those critical turn exits of limerock uphilll and dowhill, so that it can use the usable hp there better

agian, the only problem that i see with all the folks complaining of the gear box is the gap from 1st to 2nd... that is the same with most sports car these days. you use a low first to get out of the "hole" and try and control wheel spin... then, a big drop to 2nd and sacrafice the 45 to 55mph range , by being at 4500 rpm after the shift. however, since the car is so high strung anyway, cant you guys just shift the car at 6k when on the street driving around in spirited fashion? Likei said, i have this same gearing in my street car (as the gT4) and i love to shift.. never came to mind that i need a shorter 2nd gear. just curious about this.

well, thanks for the backhanded complement! ill take it! and yes, this is the reason some manufacturers choose the gears. however, if you look at most cars, and the reason for the best 0-60 times, many hit 55mph in 1st gear and if 2nd is not optimal, no big loss. remember we are talking performance cars, you want to use 1st on the auto cross. if its too low, that can be an issue. 12.1 is a prettty low 1st gear (i have that too in my street car as i say) with the broad hp curve of my car and the GT4, 2nd is at the limit of traction coming out of most turns, even autoX , and yes, it still revs out to near 75mph . sure, you can optimize 2nd to rev out at 65mph, but is that what you really want? (as long as you bring all the gears down i guess thats ok) keeping the gear closeness, then you end up with a noisy rever, on the hyway..... which i think is the most important quality of the gear box, as long as they are optimized for keeping each usuable gear in the max HP range. (which the GT4 does , sans the space after 1st gear).

so, if i hear every one here.......... some done like the space between 1st and 2nd. and some want more of an overdrive in 6th. the closeness of the gears provides no gains after .5 seconds WOT in 2nd, all the way to redline in 6th (if you can reach it). so why mess with the other gears? just to close the gap between 1-2nd? if its the shifting experience, i get that too. very low geared cars are fun to shift a lot at slow speeds (street speeds are slow). But, i think you hurt the overall performance by doing so, or really make no changes in the end, because at is stands, the Gt4 keeps the RPM in the sweet spot of power, for all gears . nothing can really be improved if you are always in the 6-7800rpm range, right?

Edit; that graph of the gears he wants to move to , matches what ive been talking about... 1st 55mph , 2nd 80+, 3rd 115, 4th 140mph ish.... thats exactly my ratios and they do work very well for the track and street. the only diffeence btween that and my street car (6speed) is that 3rd 4th and 5th are closer together