.1 gt3- minimizing understeer- any feedback re: spacers to increase front track width
09-12-2014, 11:48 PM
#31
Racer
Thread Starter
geez I can't type for crap tonite-- we have a very strong contingent of GT3's in this area that the dealer supports for a lot of track activity-- probably best dealer support I've experienced with regards to track activity since Freddie Baker sold his dealership to Penske several years ago
09-13-2014, 02:09 AM
#32
Rennlist Member
What's the whole alignment setup? Darn do I need to pull out your teeth to find out what's going on with your car? Does your shop have a chart of all the specs? Show us the chart- we can give you a better idea. Mike
09-13-2014, 02:27 AM
#33
Rennlist Member
Does your rear look like this? Please give a full chart of current alignment settings. Also forget that wrapping around the wheels when towing that it changes alignment. Been doing that many years wo issue unless my competitor is towing my car. Mike
09-13-2014, 02:55 AM
#35
I don't support messing with the track width. I know a lot of people do it but IMO it is possible to drive the car as is very, very fast.
Then again, when porsche did the 997 CupS their main modification from the 997 Cups of the time was to increase front and rear tire size & track width. And aero. And suspension. Somehow there were >100K Euro of upgrades in there lol
So, yes it does work I guess.. but a good alignment will go further and will be a more natural solution to your problems.
Then again, when porsche did the 997 CupS their main modification from the 997 Cups of the time was to increase front and rear tire size & track width. And aero. And suspension. Somehow there were >100K Euro of upgrades in there lol
So, yes it does work I guess.. but a good alignment will go further and will be a more natural solution to your problems.
09-13-2014, 06:48 AM
#36
Race Car
09-13-2014, 09:14 AM
#37
Rennlist Member
Ok cool then they should know what they are doing. This is not the usual story w dealers.
09-14-2014, 12:41 AM
#39
Racer
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It sounds like you're on the right track with what you have planned with your tech. Again, I'd probably focus on the alignment before I worried about 14mm of extra track width, but if you want to do it, that probably won't hurt anything.
The picture makes it seem like your camber is not congruent front to rear, which reinforces the diagnosis.
I am not well versed in the aero on these cars (having just moved up from a 996 with stock aero), but it seems to me that having a massive wing in back and no aero changes in the front is going to lead to weak turn in and under steer in faster turns. If the problem you are having is in all turns then I think you are on the right course. If it's only in the fast stuff then I would still check the alignment, but also move back to the stock wing and see what happens.
The picture makes it seem like your camber is not congruent front to rear, which reinforces the diagnosis.
I am not well versed in the aero on these cars (having just moved up from a 996 with stock aero), but it seems to me that having a massive wing in back and no aero changes in the front is going to lead to weak turn in and under steer in faster turns. If the problem you are having is in all turns then I think you are on the right course. If it's only in the fast stuff then I would still check the alignment, but also move back to the stock wing and see what happens.
09-14-2014, 03:56 PM
#41
Besides the alignment and bars that has already been mentioned, in addition to running front spacers which I don't see any negative in if no rubbing occurs, the LSD setup question is real - and I can speak from experience.
My car has a Guard LSD installed at the higher of the lockup settings 50/80 - and it is absolutely something that affects the car - you can feel it - especially when compared to the stock OE setup.
On acceleration, there is very noticeable 'push' on the 'entire' car - but it is unlike the front end push that the car suffered from horribly when I first got the car to the track in 2007 with the 'OE' track recommended setup. The 'OE' track specs from the manual (-2 camber front, -2.5 camber rear), OE sway bars in OE as delivered position (front full soft, rear full hard - and thus no room to further loosen the car) and in my opinion, and many others, the car would just plough like a pig with the OE tires. For me, reversing those camber specs front and rear (and actually dropping the rear camber even further to the -1.8 range) and then adding the GT2 bar is what finally changed the car - it was completely different - it turned.
I will say, that if you are just learning, if is far better to have a car that resists turning but the GT2 bar in my opinion is what transforms the car - and then you can actually stiffen the front bar by one hole as well (this is all on mk1 cars).
An upgraded or higher ramped Guard LSD, in my opinion, just allows you to be more aggressive trail breaking and on throttle at the apex - and while it definitely affects the overall car - it is the bars and the camber that is the culprit in the mk1 wrt the front end push that so many wrote about early on with this model.
A big cup wing, or an RS wing run at very high angles of attack (like my car is set up with) also needs to be accounted for as well - and it is one of the reasons that I kept finding, I think, the ability to run less rear camber than others seemed to run - and also working in combo with the 50/80 LSD.
I would get very even tire wear running -1.75 rear camber, even on Hoosiers, and it all seems to work with a 50/80 LSD and an RS wing at 15 degrees of attack - in high speed turns the car is perfectly neutral and in very low speed sharp angle 2nd gear corners the rear will rotate - I think this is a good combo.
My car has a Guard LSD installed at the higher of the lockup settings 50/80 - and it is absolutely something that affects the car - you can feel it - especially when compared to the stock OE setup.
On acceleration, there is very noticeable 'push' on the 'entire' car - but it is unlike the front end push that the car suffered from horribly when I first got the car to the track in 2007 with the 'OE' track recommended setup. The 'OE' track specs from the manual (-2 camber front, -2.5 camber rear), OE sway bars in OE as delivered position (front full soft, rear full hard - and thus no room to further loosen the car) and in my opinion, and many others, the car would just plough like a pig with the OE tires. For me, reversing those camber specs front and rear (and actually dropping the rear camber even further to the -1.8 range) and then adding the GT2 bar is what finally changed the car - it was completely different - it turned.
I will say, that if you are just learning, if is far better to have a car that resists turning but the GT2 bar in my opinion is what transforms the car - and then you can actually stiffen the front bar by one hole as well (this is all on mk1 cars).
An upgraded or higher ramped Guard LSD, in my opinion, just allows you to be more aggressive trail breaking and on throttle at the apex - and while it definitely affects the overall car - it is the bars and the camber that is the culprit in the mk1 wrt the front end push that so many wrote about early on with this model.
A big cup wing, or an RS wing run at very high angles of attack (like my car is set up with) also needs to be accounted for as well - and it is one of the reasons that I kept finding, I think, the ability to run less rear camber than others seemed to run - and also working in combo with the 50/80 LSD.
I would get very even tire wear running -1.75 rear camber, even on Hoosiers, and it all seems to work with a 50/80 LSD and an RS wing at 15 degrees of attack - in high speed turns the car is perfectly neutral and in very low speed sharp angle 2nd gear corners the rear will rotate - I think this is a good combo.
09-14-2014, 04:10 PM
#42
Rennlist Member
Regarding diffs... My stock diff was toast so replaced with Guard club-sport diff, 60/40 LSD with 88lb break away (not as aggressive as 997gt3north) when I had coolant lines welded. Had car on track last weekend for first time since. No other changes to setup... this is what i noticed immediately:
Before:
bad wiggle on heavy breaking at end of straights, would sometimes upset car and trigger abs
loose back end on tight turns, off camber turns, back end sliding and traction an issue
when calling shop chassis guy his response: get a diff, what you are describing is diff (he was 100% right LOL)
After:
No wiggle, brake and car sets and stops dead straight
Back end is substantially more planted, able to get car turned and get on throttle much harder at apex than prior
I didn't feel any additional push and the planted feeling of the car gave a lot more confidence to get the car in the corner, turned, and back on gas much faster than before, when on the gas the car sticks and turns exactly where I want it to go
Before:
bad wiggle on heavy breaking at end of straights, would sometimes upset car and trigger abs
loose back end on tight turns, off camber turns, back end sliding and traction an issue
when calling shop chassis guy his response: get a diff, what you are describing is diff (he was 100% right LOL)
After:
No wiggle, brake and car sets and stops dead straight
Back end is substantially more planted, able to get car turned and get on throttle much harder at apex than prior
I didn't feel any additional push and the planted feeling of the car gave a lot more confidence to get the car in the corner, turned, and back on gas much faster than before, when on the gas the car sticks and turns exactly where I want it to go
09-14-2014, 04:24 PM
#43
Rennlist Member
Hey guys,
I noticed some understeer with my car and just brushed it off thinking that I just don't know how to drive the thing yet; but upon closer inspection I found that my front bar is set on full stiff and rear bar on full soft.
A little background: I'm a fairly decent driver and can do pretty much whatever I want with a front engined RWD car. Now being new to the 911 world I'm taking it easy trying to learn the dynamics of the rear engined setup.
If I understand correctly though the current sway bar settings on my car are basically set for maximum understeer. The front is too stiff to allow it to bite and turn and opposite on the rear, too soft to turn (Correct me if I'm wrong!).
Thus I was wondering 1) what are the stock settings? And 2) what settings would you recommend I start with to shoot for a more neutral handling with a tendancy oversteer?
Thanks!
I noticed some understeer with my car and just brushed it off thinking that I just don't know how to drive the thing yet; but upon closer inspection I found that my front bar is set on full stiff and rear bar on full soft.
A little background: I'm a fairly decent driver and can do pretty much whatever I want with a front engined RWD car. Now being new to the 911 world I'm taking it easy trying to learn the dynamics of the rear engined setup.
If I understand correctly though the current sway bar settings on my car are basically set for maximum understeer. The front is too stiff to allow it to bite and turn and opposite on the rear, too soft to turn (Correct me if I'm wrong!).
Thus I was wondering 1) what are the stock settings? And 2) what settings would you recommend I start with to shoot for a more neutral handling with a tendancy oversteer?
Thanks!
09-14-2014, 04:48 PM
#45
Rennlist Member
Are you in SoCal? Who is doing your setup/alignments?
Going off memory but with GT2 rear bar I have middle rear, 2 from soft front.