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Changing ride heights doesn’t change F/R static weight distribution, but it changes L/R static weight distribution at each axle, because a car has four wheels, not three. When you corner balance, you are effectively making sure L/R distribution is equal.
Changing rake has effects on the dynamicload distribution, and therefore the handling, not the staticweight distribution between axles.
If you lower the rear (both corners), you will have LESS (maybe not significant) static weight on the rear (F/R)
If you lower the rear (both corners), you will have LESS (maybe not significant) static weight on the rear (F/R)
No, it won’t change static weight at the rear axle. But it will change the aero effects and handling of the car.
The static weight distribution between the F and R axles is determined by location of the CG of the car (viewed in plan) relative to the axle locations. That is not affected by the rake. This is simple statics.
No, it won’t change static weight at the rear axle. But it will change the aero effects and handling of the car.
The static weight distribution between the F and R axles is determined by location of the CG of the car (viewed in plan) relative to the axle locations. That is not affected by the rake. This is simple statics.
No. The quote you gave pertains to lateral load, not gravitational weight.
Changing ride heights doesn’t change F/R static weight distribution, but it changes L/R static weight distribution at each axle, because a car has four wheels, not three. When you corner balance, you are effectively making sure L/R distribution is equal.
Changing rake has effects on the dynamicload distribution, and therefore the handling, not the staticweight distribution between axles.
Thanks for that correction. Of course you are 100% correct. I did not think past the fact that lowering the car puts more grip back into the rear. Assuming that a bit more weight went back there to accomplish this was false. It just changes the heights of the axles relative to the center of gravity as you said and therefore the balance of the car. Getting the butt lower helps with the dynamic loading of the car in a corner, letting the rear dig in a little bit more relative to the front. My spec-Boxster friends play with ride heights all the time. A 5mm change in one axle ride height is akin to changing the sway bar settings.
I love this forum. If you don't know something or get it sightly wrong, someone else can set the record straight, and we all learn more from each other.
I have a table from Porsche Motorsports that shows all the affects of changing ride heights. I will post later when I am at home.
Last edited by lovetoturn; 04-24-2024 at 11:56 AM.
As promised, here are some monographs from Porsche Motorsports for the 718 GT4 Clubsport. The Clubsport rides lower than the street 4 RS, but these numbers should be relatively comparable between the cars to give you an idea of what is happening.
Affect of front shim in camber
Affect of shim on rear camber.
Affect varying rake on overall downforce and front to rear ratio of downforce.
So on the GT4 RS, raising the rear by 5mm increases total downforce by 1.1% x 488 pounds or 5.4 pounds and a 10mm raise increases it by 9.3 pounds. The interesting part is that the 5mm increase in rake then sends 1.6% more of that 493 pounds or 8 pounds to the front. With a 10mm raise in rake 3.8% more of 493 pounds or 19 pounds goes to the front. To put that into perspective, the spoiler extensions and canards from Silver Rocket add about 23 pounds of front end downforce. So you can see that adding a lot of rake can have significant affects on the front downforce and the overall balance of the car. If you will notice, Manthey adds a lot of rake to the GT4 and 4RS as compared to the generally understeering OEM setup in order to help the front end work better .
Last edited by lovetoturn; 04-26-2024 at 02:19 AM.
Pretty much my take on the GT4 RS. Much more fun to drive than my 992.1 GT3T which I traded for the GT4 RS.
Always a comparison.....cant you just enjoy the 4RS without bad mouthing the 992 gt3. They are both unique experiences in a perfect world own both. They each. have their strengths and weakness no one car is perfect.
As promised, here are some monographs from Porsche Motorsports for the 718 GT4 Clubsport. The Clubsport rides lower than the street 4 RS, but these numbers should be relatively comparable between the cars to give you an idea of what is happening.
Affect of front shim in camber
Affect of shim on rear camber.
Affect varying rake on overall downforce and front to rear ratio of downforce.
So on the GT4 RS, raising the rear by 5mm increases total downforce by 1.1% x 488 pounds or 5.4 pounds and a 10mm raise increases it by 9.3 pounds. The interesting part is that the 5mm increase in rake then sends 1.6% more of that 493 pounds or 8 pounds to the front. With a 10mm raise in rake 3.8% more of 493 pounds or 19 pounds goes to the front. To put that into perspective, the spoiler extensions and canards from Silver Rocket add about 23 pounds of front end downforce. So you can see that adding a lot of rake can have significant affects on the front downforce and the overall balance of the car. If you will notice, Manthey adds a lot of rake to the GT4 and 4RS as compared to the generally understeering OEM setup in order to help the front end work better .
Just to add… this is on the Clubsport/Clubsport RS with rear wings which is quite different than the road car wings, and much more effective at producing df, and yes the whole car is treated as a wing.
Always a comparison.....cant you just enjoy the 4RS without bad mouthing the 992 gt3. They are both unique experiences in a perfect world own both. They each. have their strengths and weakness no one car is perfect.
His opinion is the 4RS is more fun to drive, deal with it :-), he is not bad mouthing anything just voicing an opinion. People do get touchy.
Same reason I own one and I have 4 Porkers but I don't want a 992 GT3, that does not make it a bad car, I just don't want one either, the thread is called driving impressions of the 4RS, so the best car to compare it with is a 992 GT3 or the 991.2 RS as they are all about the same money atm.
Always a comparison.....cant you just enjoy the 4RS without bad mouthing the 992 gt3. They are both unique experiences in a perfect world own both. They each. have their strengths and weakness no one car is perfect.
Originally Posted by mrd_spy
His opinion is the 4RS is more fun to drive, deal with it :-), he is not bad mouthing anything just voicing an opinion. People do get touchy.
Same reason I own one and I have 4 Porkers but I don't want a 992 GT3, that does not make it a bad car, I just don't want one either, the thread is called driving impressions of the 4RS, so the best car to compare it with is a 992 GT3 or the 991.2 RS as they are all about the same money atm.
I've done a lot of car comparisons. That can be useful to understand the differences and similarities of cars. But ultimately, I've moved towards the view that car comparison can be counterproductive, because it can make one approach a car very analytically and reductionistically. Instead, I find it better to just drive and experience a car in the moment, trying to holistically appreciate the unique recipe which makes the car what it is. If I'm eating steak in a restaurant, I savor and enjoy the steak as I'm eating it, and don't find myself comparing it to lobster or salmon.
The 992GT3 especially a Manual is so different to a 4RS in the way they drive that it makes no sense to compare them using the same parameters. Ideally you would have both in the garage and just drive the one depending on what mood you're in on that particular day. A 992GT3 Touring Manual makes a perfect pairing with a 4RS imo.
I've done a lot of car comparisons. That can be useful to understand the differences and similarities of cars. But ultimately, I've moved towards the view that car comparison can be counterproductive, because it can make one approach a car very analytically and reductionistically. Instead, I find it better to just drive and experience a car in the moment, trying to holistically appreciate the unique recipe which makes the car what it is. If I'm eating steak in a restaurant, I savor and enjoy the steak as I'm eating it, and don't find myself comparing it to lobster or salmon.
But YOU WILL compare to another steak in another restaurant.
The 992GT3 especially a Manual is so different to a 4RS in the way they drive that it makes no sense to compare them using the same parameters. Ideally you would have both in the garage and just drive the one depending on what mood you're in on that particular day. A 992GT3 Touring Manual makes a perfect pairing with a 4RS imo.
for what reason ?, it's not like it's a great road car ! the Touring, it's still bouncy, hard as nails and you have to swap it out on road tyres but it will still tram line and make tons of tyre noise ! , then whats the point any way. not sure why people want to own more than one GT car. I would under stand if you said 992 Turbo S and a 4RS or a GTS etc. But owning a touring and a 4RS no thanks.
I have 4 atm but all different. I daily a GTS, I have a 997 for slower fun and it's just cool, I have my Spyder for sunny days(so it never gets used) and the 4RS for track and blats. A touring don't fit anywhere, it's also **** at touring , I would take my GTS ! very over rated cars esp as you pay more than a GT3 for one ! imho.
04-24-2024, 09:22 AM
