Jimmy-D

^Would the Dealer do this or need to find a place that would specialize in this?

jphughan

Dealer or indy would be fine. If you were doing a more involved alignment with shims and aftermarket parts it would be worth finding a more specialized shop, but a basic alignment is a basic alignment.

Jimmy-D

AERO SETTINGS:

Setting the car’s aero is probably the easiest, and often the first, adjustment folks make before getting to the track.

It involves two easy changes: First, remove the two front aero ducts at the bottom of the car, right in front of the front wheels. It can be done by simply unscrewing the screws with a Torx T25 bit. Second, unscrew the retaining bolts on the rear wing uprights with two Torx T30 bits and reposition the wing in the more aggressive position. You’ll notice it is a very slight adjustment, so don’t stress if it doesn’t move radically – it is not suppose to. You will have to completely remove the bolts in order to reposition the wing and not just loosen them.

I would like a little more downforce. Does this above work?? Any pictures on how to adjust the wing to the more agressive position_ I guess trying to figure out what/how we are adjusting
Also - if I adjust the rear sway bar to hard and leave the front to med will this give me a little less understeer and does this, at all, make the rear suspension any more harsh because right now the suspension is very road compliant and eats rough roads and bumps pretty darn good on the street

myBailey07

Here's a link with pics that describes how to set the aero and the impact - good info.

https://rennlist.com/forums/gt4/8965...ustment-4.html

Yes, it does increase the downforce slightly; however, you will be very unlikely to notice it at all driving on the street.

Adjusting the rear sway to hard and front to medium does reduce understeer as it effectively slightly reduce your rear grip vs the front. Very simplistically, the sway bar has more to do with controlling body roll during turns whereas your shock and spring tuning controls "bump compliance" on the street, so, setting the rear bar to hard should have no noticeable impact on the road compliance during street driving. It is also so easy to change in the rear that if you don't like it, you can set it right back without any issues.

Hope it helps.

Jimmy-D

^Thanks. Gave me all that I needed

Just going to get a basis alignment and will adjust rear sway bar and leave the aero alone

jphughan

You're feeling the need for more downforce and noticing understeer just driving on the road?

If you haven't already, put 1000 miles on the car and then get the best alignment you can with the stock hardware. That will probably help handling somewhat judging by the alignments people have seen from the factory. But other than that, fwiw I still have my aero and sway bars in their factory positions and don't have any complaints about downforce or understeer even on track. Granted I'm still learning the car (I believe that one should learn to drive what one already has before deciding how it "needs" to be changed) and my previous E92 M3 had a fair amount of understeer even with camber plates, so my reference points may be different from others here. On the other hand, as BRNGT4 described in his thread, sometimes it's just about adapting your driving to the car rather than trying to adapt the car to you. The quick version is that he had a pro driver take his car out, who said the car had no understeer; BRNGT4 was stunned by this since understeer had been a gripe of his, and the pro driver just said to trail brake deeper into the corner to get more rotation done early before putting the power down. Once BRNGT4 started doing that, his understeer gripes went away. I can't remember what his sway bar settings were, but again, try getting a feel for the car first.

And I'm not sure how much you care about this, but the supplement about driving on a racetrack says that sway bars and aero should be left in their factory positions for driving on public roads.

myBailey07

Updated the top post with:

(As usual, updates in BLUE)

1) TPMS on track, or not and TPMS "freak out" tip
2) Section for maintenance considerations for those that track the GT4


As always, can use the help with additional info or corrections. As a previous boss told me: "Son, you might not be always right, but you always have an opinion"...lol

texasviany

The suggested intervals in the manual are assuming that you are running OEM tires. If you are running sticky tires, like Hoosiers, I plan to cut all the maintenance intervals way down. I plan to change my wheel bearings every 2000 miles and the oils after every 2 track days. I do a routine nut and bolt check, with alignment after every event. I change the brake fluid every 2 weekend events as well.

myBailey07

Good point with the sticky tires! Wheel bearings every 2k miles, oil every weekend and brake fluid every second weekend just seems VERY aggressive to me, but then again, erring on the side of too frequently is obviously much better than erring on the other side.

jphughan

Considering that Porsche's recommended interval for wheel bearings front and rear is 12K and 6K track miles, respectively, and oil is also 6K, that seems grossly excessive even taking the grippier tires into account. And if you get Castrol SRF you can stop changing brake fluid anywhere near that often.

9001rpm

Why you may have a point. I think you may be grossly underestimating the additional loads placed on the suspension vs a traditional "street tire". Look at the ClubSport as a potential reference point. From what I recall they have beefed up suspension components and increased service intervals to deal with additional grip/loads.

Fluid changes also makes sense as you can effectively push the car harder, for a larger period of time, due the increased grip.

There is a reason everyone who wants to be a DE champion runs Hoosiers... You want to play racecar driver then be prepared to maintain your car like, ding ding ding, a racecar.

mrd_spy

why do with have to throw away a mid engine driving stye and go back to driving these like 911's though, it's going to be slower than a 911 if you drive it like a 911 as the GT4 don't have the traction out the corners.

All well and good over rotating the car into the apex under brakes, but the best bit about mid engine cars is mid corner speed, drive it like a 911 because you have a crap geo will just make you slow imo. or you hit the limit of the car and that's that, no where to go on stock setting once you revert to 911 driving style. May as well buy a GT3.

jphughan

I wasn't there, but I'm going to guess that a pro driver managed to drive the GT4 in a way that optimized both for its layout AND for overall speed. BRNGT4 said that the pro driver was lapping 3 seconds faster than he was, but once he (BRNGT4) adopted the technique the pro driver described and I mentioned above, he shaved 1.5 seconds off his own lap time, so I don't think the reason the pro driver didn't feel any understeer was because he used a driving style that was slow for this car. And so far I haven't had any problem with traction out of corners at least compared to my M3, nor have I seen others complaining about power out of corners -- quite the opposite, actually. I attribute that partly to having such wide and sticky OEM rear tires for just 385 hp and also the large front to rear tire stagger. Yes the GT3 has an extra 10mm both on rear tire width and stagger AND it has the advantage of more weight in the rear, but it's also got another 100 hp.

So if driving it more like a 911 is faster, then I personally would rather do that than stubbornly stick on principle to what "should" be faster for a mid-engine car but may not be for THIS mid-engine car. But hey, everyone drives differently.

texasviany

I wil examine the bearings after 2k and evaluate them. I was a professional factory rally driver and certain maintenance issues are pounded into your belief system!!

myBailey07

That would be good info to have to see how they look at 2k miles. Part of why I started the wiki was for us track guys to collectively gather info such as this, learn from each other, and determine collective guidelines for how to set up the car and maintain the car.