GTgears

Hello Chris,
About 18 months ago I moved my business into an out building on my property. I'm no longer open to the public. Sorry. Though I'm often at the Boulder Cars n Coffee the first Saturday of each month.

Regards,

Matt

BGB Motorsports

I think everyone is best served tracking the car at least once or twice before jumping in feet first but at the same time I am about to list all of the mods that are ready for this car right now.

We have used Matt's gears with much success in racing; we have purchased 4 modified ECUs thus far and several GT4 owners in Europe have purchased modified ECUs. Unlike previous models like the GT3, the parts are already through R&D and now we're just waiting for cars to arrive to sell parts, not retrofit or test them. Cheers!

user1029

That's like a drug dealer saying just start with weed first before I show you the whole gamut of what I'm offering

I know I'll be sending my car to you guys Shorten up the gears before the 991 GT3 engine swap

hot-J

Do you know how beneficial ECU tuning will be yet?

BGB Motorsports

It is hard to quantify right now as to what it would be for just the ECU because the last 2 I have dyno'd all had PDK to start and had added headers, air filters, the ECU flash and one was with a 991 Power Kit conversion and the other just a standard 991 3.8L swap with an IPD plenum. They're all PDK though and while I don't think the drivetrain loss is nearly as egregious as others think, it's still not apples to apples enough for my OCD.

I would expect the flash to net 15 crank hp because i'm a conservative guy that only likes to speak what I see. We are awaiting the arrival of our car for the shop and have one coming sooner from a customer that wants to send it to us for a list of bolt-ons and maybe then I could do a straight ECU comparison. I still need to do a stock ECU comparison for my 3.4L customers that are waiting but it requires my car going off the road for a week or so and I haven't yet done it.

If we're getting 415 HP with our regular 3.8L swaps and 440 + HP with the Power Kit cars then using the same mods and procedures would net the same for the GT4 owners.

neanicu

BGBMotorsports,thanks so much for your input!
Would you like to comment a bit about the fitment of the Powerkit intake manifold on the 981 platform? I'd be really interested as to what Porsche means by " fitment issues with the Powerkit intake on the new GT4... "

BGB Motorsports

I don't want to go too much into detail on this but only say that we have done 3 so far. It's definitely not "plug n play" by any means but we made it work. It's not pretty but we made it work.

neanicu

Thank you for the response.
You guys are awesome BTW!

Mvez

For DE work, there won't be anything wrong with this gearing. Virtually every review says the same for track work. For street, don't short shift while in 2nd, again, pretty simple.

Reminds me of the difference between .1RS and .2RS. All you had to do is actually use 2nd gear, and the .2RS really wouldn't pull on you much until top end where the HP advantage really took over.

It cracks me up how little 2nd gear seems to get used. It's a gear, learn how to use it.

jphughan

Guilty as charged. I tend not to use it on track because the appropriate amount of throttle blip on a 3>2 shift is much more than on a 4>3 shift and therefore the effects of not getting it quite right are amplified. Additionally, 3>2 is a more difficult shift to execute on the lever itself compared to 4>3 and even compared to 5>4 because at least with 5>4, the detente naturally pushes the lever over into the 3-4 column, whereas with 3>2, you need to pull enough to overcome the detente and avoid getting stuck between the 2nd and 4th gear gates, but not so far over that you end up getting stuck in the Reverse gate. I know it sounds whiny, but on a track, the thought of trying to execute a 3>2 shift correctly and smoothly at the end of a heavy braking zone has sometimes prompted me to roll through the corner in 3rd.

I face this dilemma at CotA quite often because several of the hairpins are "between-gear" corners for my E92 M3 6MT. If I roll through in 3rd, I'm out of the power band on corner exit. If I go through in 2nd, I have a lot more power, but the gear isn't usable for very long at all, and of course getting that short burst of extra power required me to contend with an extra downshift and an extra upshift. It's one of the few times I've wished I had a DCT -- sort of. Looks like I'll have to get used to using 2nd on the GT4 though, unless the extra speed I can carry through corners on these tires plus the better power to weight completely offset the taller gears. But if they don't, at least I'll have the option of using auto-blip on the track to help with those shifts.

vantage

Never shift to second? Too difficult physically? Whoa! I use it all the time in the canyons and at least once on every track I visit except willow springs. It's really not that hard!!

The issue is how the car comes off slow corners In any environment and that on a mountain road you won't be doing much shifting at all with such a tall second gear. You won't be experiencing red line as often on the street nor will you be downshifting as much.

I think you have things backwards. The taller gearing of the GT4 cause you to shift less often not more.

stout

Matt and John,

Thanks for chiming in here. Stupid question, possibly: Could the final drive be swapped to keep the 1-5 splits as is but effectively lower the top speed in each gear, and then a taller sixth gear be added for cruising?

I agree with the advice to spend time with the car and see about whether one wants to change anything. Most of the observations so far, mine included, were based on a single day with the car, or more accurately just a few hours. That said, the back roads we ran, and the top speeds seen in 2nd and 3rd were enough to have me pining for shorter gears. Alternately, 6th felt a bit short at 75-80 mph—leaving me wishing for the 991's 7th, especially with that 3.8 punting a lighter car down the road.

pete

jphughan

This was asked on Page 1 of this thread and answered with a reply containing a link to another thread that contains a very thorough answer to the final drive question.

jphughan

As I said, it's not just the difficulty of the shift, which I agree isn't that hard. It's doing it under heavy braking properly where doing it improperly could significantly upset the car, plus the "cost" of two extra shifts that has to be weighed against the benefit of a (for me) very brief period of extra power.

As for taller gears meaning shifting more or less often, if the taller gearing means that for the speed range at a given track segment, you have to downshift to be in the engine's power band for the lower end of your segment speed, but then upshift again to reach the high end of your segment speed, then you may well have to shift more often overall even though each gear can technically cover a wider range of speeds. For example, I can imagine a scenario where the GT4's 3rd gear may have too little torque at my mid-corner speed but its 2nd gear won't go as high as I'll need before hitting the braking zone for the next corner, in which case I could have to shift down to 2nd and still shift back up to 3rd later, whereas on another car the gearing may be such that 3rd offers both enough torque at my mid-corner speed AND enough breadth to reach the top speed I need.

neanicu

To me the gearing issue is simple : I like to shift,the more the better. Taller gears means less shifting,but I'll live...