lee88

I have a 981 Boxster which was built by BGB Motorsports in addition to my 993TT. The Boxster conversion included 3.8L motor from 991S, X73 suspension w/ lower ride height, brake upgrade (991S rotors / calipers, 991 GT3 master cylinder), Cargraphic full exhaust, etc. So in terms of specifications it's fairly close to a 981 GT4 with a little more power output and other than the exhaust, it's all Porsche OEM stuff. On the dyno my BGB car puts out 350 rwhp and 287 ft-lb torque, so depending on what assumption you use for drive train loss you're something like 410-430 hp at the crank. BGB does these conversion builds on both 981 Boxsters and Caymans so a lot of folks who have interest in the GT4 have gotten them, or folks like me who got them before the GT4 was announced (my car was built in fall 2013).

In terms of driving experience, both the 3.8L 981 and my 993TT are exhilarating but they're obviously different. I've tracked the 981 Boxster but not the 993TT, have done plenty of street driving including some long distance touring in both cars.

Power/Acceleration
Both cars have prodigious power but in different ways... while the 993TT doesn't have the turbo lag of a 930 or something, you still get the "boost" sensation as the RPMs build whereas the NA 3.8L delivers the power more progressively. Much higher redline on the 3.8L motor (7800 rpm) and it feels like it revs effortlessly... when you blip on downshifts (my Boxster is 6spd, BGB can build them w/ PDK if you like) the tach comes up fast almost like telepathy. Off the line the 993TT probably still has a slight advantage with AWD, but I'm fairly certain the 3.8L Boxster still accelerates faster pretty much everywhere except maybe 0-20mph. The 993 has that air cooled sound though.

Braking
They're both awesome. BGB's 3.8L conversion includes the 991S rotors and calipers as standard, but I upgraded to the 991 GT3 master cylinder to try to get a nice firm pedal feel more akin to the 993TT which IMO is still perhaps the best braking performance and feel Porsche has ever achieved.

Handling
The 981 chassis is very very good. With the mid-engine advantage it's just more neutral and planted than a 993 can ever be. Even with the 3.8L motor, my 981 Boxster still weighs ~300 lbs less than the 993TT so that also helps. My 993TT has PSS10's and is set at Euro ride height so handles pretty well, but the 981 chassis is just superior in this regard both on the street and most certainly at the track.

Shifting
Both very good. If you haven't driven a 981 or 991 yet, the most noticeable difference to a 993TT is the position of the shifter. With the 981/991 the center tunnel is much higher up... almost like a Carrera GT if you've seen one of those, whereas the 993TT still has the lower floor mounted shifter that you have to "reach" for a bit more.

Overall they're both awesome cars, I like them each in their own way. I obviously haven't driven a GT4 yet but my 3.8L 981 is probably fairly similar. The GT4 seems like a great car and obviously a Porsche factory product not a built car, but to the extent you're thinking of going this route I can't say enough good things about my 981 build or the guys at BGB. Really top notch both in their execution (BGB started as a race team, they won Rolex Championship in GX class) and in experience dealing with them. Plus you can get a 3.8L Cayman build from them immediately and for significantly less than waiting for a GT4 allocation and paying markup over MSRP.

mausone46

lee88
awesome garage!

Mike J

I thought that BGB stated in one of the other threads that they cannot build the total equivalent to a GT4 as cost effectively at Porsche - primarily because of the GT3 components, etc?

is the gearing in your car the same as the GT4 - very long 1st and 2nd? That would give a 993Tt and your car quite a bit different feel as well.

Cheers,

Mike

lee88

Yes, you're correct that these BGB built cars aren't a GT4 clone and I defer to the BGB guys and don't want to speak for John who's reasonably active on other RL forums here. The only GT3 part in my car is the 991 GT3 brake master cylinder whereas the front suspension of GT4 is nearly all derived from GT3 (hubs, control arms, steering rack). In addition to the mechanicals the aero kit is obviously different too. So to be clear I wasn't saying it's a like for like comparison, but IMO it's reasonably close to offer some broad observations to the 993TT.

Re: gearing, my understanding is the GT4 shares the same ratios as the GTS and 981S models.
GT4 Specs
GTS Specs
981 / 981S Specs

My car started life as a base 981 Boxster, so I benefit from slightly shorter gearing across the range.