135i understeer--

[02rsxpilot]

Originally Posted by Ganicki

No. That's exactly what I wanted to hear. Just like golf. Get the basics down good and strong practice practice practice. Then when I feel that equipment will help the cause, I can try some things. Thanks

Excellent analogy. Millions of golfers prefer to spend thousands every year on new equipment when the monkey swinging the club is the problem. Sure, new clubs will give you a little different feel, or look, that might have a temporary effect on your swing and therefore your results, but shortly thereafter you are back where you started, or maybe have a new set of problems.

Track driving is the same thing, except even more expensive! That being said, I always back up one step and acknowledge that modding is part of the fun, so don't feel like you can't do it until you're driving skills are Schumacher-esque. Just know that most of us on this forum genuinely want to make sure you get the results you are looking for without wasting money chasing every poster's two cents.

[Ganicki]

Originally Posted by 02rsxpilot

Excellent analogy. Millions of golfers prefer to spend thousands every year on new equipment when the monkey swinging the club is the problem. Sure, new clubs will give you a little different feel, or look, that might have a temporary effect on your swing and therefore your results, but shortly thereafter you are back where you started, or maybe have a new set of problems.

Track driving is the same thing, except even more expensive! That being said, I always back up one step and acknowledge that modding is part of the fun, so don't feel like you can't do it until you're driving skills are Schumacher-esque. Just know that most of us on this forum genuinely want to make sure you get the results you are looking for without wasting money chasing every poster's two cents.

Thanks a bunch. I'll let you know the outcome after this weekend. HPDE at the new corvette museum track. Can't wait

[Kgolf31]

Originally Posted by fe1rx

Clearly we need to step back even further:

1) brake in a straight line
2) release the brake as you turn in
3) turn in smoothly
4) maintain a balanced throttle to the apex
5) don't add throttle until you start unwinding the steering
6) add throttle smoothly
7) if you are overcome by the urge to spend money on your car, modify your car per Kgolf's list, starting at the top pausing to check the results whenever you run out of money

Sorry to have taken your bait. I knew you really didn't want to hear the answer.

Yea, this is probably the best answer.

IMO you need to learn how to drive the car (no to sound like a douche) correctly before you know what needs to be done.

If you don't know how each part you throw on the car affects the handling dynamics of the car, then IMO you're not ready to put it on the car.

[Ski Killset]

500whp and an LSD will cure understeer too

[Sauce]

The biggest issue is always the driver, driving a car that understeers is actually a REALLY good thing to learn on. Learning how to rotate a car that may not want to is really, really valuable just as a very loose car can teach you a lot. It will make you understand what is happening and what to do. A 135 bone stock will rotate just fine if you do things perfectly.

When looking at the car, you ALWAYS want to start from the ground up, ALWAYS. I can't emphasize this enough. Any advice otherwise is wrong. The alignment and tires are the first thing. In your case, I'm sure you have street tires with tread on them, so start with the alignment. Camber plates on this car give you the adjustability necessary, toe is a beautiful thing in terms of turn in and rotation, you need to balance your priority on tire life and track prowess because on a street car it is all a compromise. Toe and camber are huge on track and will also dramatically reduce tire life on the street. Then tire size front to rear when you replace, again we are limited by our platform so fit as much rubber as you can. Also, free adjustment can be made to your chassis with tire pressure. Don't underestimate the impact this can have, you can't go by the general rule of thumb where more pressure lessens grip and less adds it. Figure out what works with your tires and talk to people that have experience with them on track. You may want to compromise exit traction for balance in the front but that is personal to you. Your suspension setup is dictated by these factors which is why you need to do them first. Alignments are never set and done, you play with them non stop especially as you change other factors.

After that you play with shocks, bushings and springs. Bushings on a street car are purely for compromise, you need to understand that. On a race car they are there (and metal) only to maintain your suspensions geometry at all cost, the less things move the more predictable the suspension is and the more efficiently it works. On a street car they balance noise and vibration with maintaining integrity. Just know that they my improve feel but until you are fighting for tenths and hundredths as a driver they will NOT make you faster. There are many schools of thought on shocks and springs, the main thing is that the two need to be put together with one another in mind. The better the tire is in contact with the ground, the better it will work. You can jack up rates and damping to balance a car, but understand you are doing that by DECREASING grip. The softest possible while maintaining body control is best, not vice versa.

Lastly you go to sway bars. They are a very fine adjustment tool in the grand scheme of things. You need to know the bigger the bar, the less independent your suspension is. Simply, what a sway bar does is transfer weight to the outside tire, faster. With an open diff as in our cars, you need to take care because this can lead to the inside tire lifting (think mk1 golf gti) and that means either spinning of that tire or absolutely no forward acceleration if it's all the way off the ground, both make the car unpredictable and slow.

I left out diffs and other very fine factors because you are not very far along and those are major changes that cost a lot of money. I would take a car that has seats, a perfect alignment with good tires over a car that has high dollar suspension stuff thrown together.

[John_01]

You need to exercise a degree of caution on a circuit when driving on street tires. Its very easy to overheat them and suddenly find the balance of the car has changed. A powerful and heavy car such as the 135i will hurt its tires when driven on a track. It will get very slippery as street tires are not designed for it. I suggest to look at tires before you go very far with other modifications.

Simply adding a lot of front camber on an otherwise stock 135i will make it more it quite prone to oversteer when the rear tires get a little bit stressed. A few things you can do to add stability are: Proper sport tires, upgraded rear sub-frame bushings, and possibly a firmer front sway bar. I think that for driving on a properly fast circuit understeer is a good setup. On many tracks its possible to get good results by trail-braking to combat the understeer.

[Kgolf31]

Originally Posted by John_01

You need to exercise a degree of caution on a circuit when driving on street tires. Its very easy to overheat them and suddenly find the balance of the car has changed. A powerful and heavy car such as the 135i will hurt its tires when driven on a track. It will get very slippery as street tires are not designed for it. I suggest to look at tires before you go very far with other modifications.

Simply adding a lot of front camber on an otherwise stock 135i will make it more it quite prone to oversteer when the rear tires get a little bit stressed. A few things you can do to add stability are: Proper sport tires, upgraded rear sub-frame bushings, and possibly a firmer front sway bar. I think that for driving on a properly fast circuit understeer is a good setup. On many tracks its possible to get good results by trail-braking to combat the understeer.

I'd never suggest tires as a first upgrade to do....ever.

Tires that offer more grip also let go of that grip alot quicker. They do not communicate as much and when they let go, well you're in for trouble.

It isn't bad at all to run on the tires you have the first couple of times. Get a feel of when you're approaching the limit. They will talk to you when it happens and you build muscle memory off of it.

Also, camber does not solve push on these cars.

Anyways, here is what I'm trying to talk about. These are on Hankook RS3s. You can see you don't hear much when the RS3s let go from the grip...however you can see the steering corrections I'm already making to solve the issue because I know what the car does.

I'm not an expert, but considering I was the fastest street tire car out there and placed 20/170th, I would like to say I do hold some merit.

[John_01]

Originally Posted by Kgolf31

I'd never suggest tires as a first upgrade to do....ever.

Tires that offer more grip also let go of that grip alot quicker. They do not communicate as much and when they let go, well you're in for trouble.

There is a whole discussion about which tires to choose as you can't generalise they all have the same characteristics. Possibly part of the difference may be because of different requirements for Auto-x vs a high speed circuit. Your car also has less midrange torque than a 135i, so you aren't going to put the same stress on the rear tires. I am not saying you are wrong, but it may be looking from a different perspective.

Originally Posted by Kgolf31

It isn't bad at all to run on the tires you have the first couple of times. Get a feel of when you're approaching the limit. They will talk to you when it happens and you build muscle memory off of it.

I agree its ok to start on the tires you have. Just be aware of their limitations so it doesn't take you by surprise.

[fe1rx]

Originally Posted by John_01

I agree its ok to start on the tires you have. Just be aware of their limitations so it doesn't take you by surprise.

More generally, it is ok to start with the car you have. The challenge is always to drive within the limitations of what you have (braking, accelerating, cornering).

Few street cars have sufficient braking capacity that they won't eventually fade on a brake-intensive track. The solution to that is to manage what capacity you have by either limiting hot laps or braking earlier and thus slower and thus putting less energy into the brakes. It takes some real discipline to manage your brakes at their fade limit, especially when your buddy with the Cayman is catching you in the braking zones (on stock brakes).

Similarly, it is tempting to try to hang with the Cayman in the corner, but he has more ultimate cornering grip because he has better balance at the limit. You are just going to abuse your front tires by pushing too hard if you try to match his apex speed. But more generally, there is never any point in pushing beyond the peak grip of the front tires, and doing that takes skill and discipline regardless of where that peak is.

Sticky tires will make your braking woes worse because they can put more energy into your brakes. You will be able to corner faster but will still need to manage your front tire grip if you don't want to kill your tires.

When you find the limits of your car at the track, you may want to go home and figure out how to raise those limits (which invariably will be expensive), but when at the track, the challenge is always to drive within those limits.

Of course sliding around until you cord a tire is its own kind of fun and it is instructive in its own right, but it is expensive when you are paying for your own tires, and it is not the right way to develop basic track driving skills.

[Kgolf31]

Originally Posted by John_01

There is a whole discussion about which tires to choose as you can't generalise they all have the same characteristics. Possibly part of the difference may be because of different requirements for Auto-x vs a high speed circuit. Your car also has less midrange torque than a 135i, so you aren't going to put the same stress on the rear tires. I am not saying you are wrong, but it may be looking from a different perspective.


I agree its ok to start on the tires you have. Just be aware of their limitations so it doesn't take you by surprise.

I own a Z4M as well, and it's been on the track (specifically Mid-O)

The stress on rear tires on a track should be significantly less than autocross. Especially since you're most likely in 3rd or 4th gear on a track vs 2nd gear on autocross.

I never spun 265 rear RS3s on the track unless it was raining.

[Suds]

Our 135's have MacPherson strut suspension, body roll creates positive camber, design flaw.
I bought a Vette to fix this problem it also came with a real LSD.

I still enjoy my One on the street but when you push it, it plows.

[02rsxpilot]

FWIW, this is the best mod I ever bought:Ultimate Speed Secrets

Massively increased my understanding of vehicle dynamics and proper driving technique. Also much easier to understand compared to other racing books I've read. (It will address nearly everything folks on here are posting about--alignments, grip, handling balance, braking, etc...)

Try finding any performance part for $16 that will match the lap time improvement you'll get from this.

[MightyMouseTech]

Originally Posted by Suds

Our 135's have MacPherson strut suspension, body roll creates positive camber, design flaw.
.

Ya, because 911's handle like shit.

Adding front camber makes a world of difference. Can't believe how little our cars come with from the factory (about -0.5 degrees) Even spirited street driving will get you on the outer shoulder. Designed in under steer when pushed.

When we were running Grand-Am in a 325 at Daytona, we were running -4.5 in the front, and we wished we could have run more. And that is with springs that were nearly 1000% stiffer than stock.

[Kgolf31]

Originally Posted by Suds

Our 135's have MacPherson strut suspension, body roll creates positive camber, design flaw.
I bought a Vette to fix this problem it also came with a real LSD.

I still enjoy my One on the street but when you push it, it plows.

You left one thing out.

Caster....and lots of it.

[Suds]

Just because a 911 with a rear engine, that has been tweaked through like 4 generations and 50 years dosen't make it a good design. You can polish a turd and make It shinny.

And yes I have owned a 911, but with the 997 turbo prices so low it may be time to buy my second.

[Kgolf31]

Originally Posted by Suds

Just because a 911 with a rear engine, that has been tweaked through like 4 generations and 50 years dosen't make it a good design. You can polish a turd and make It shinny.

And yes I have owned a 911, but with the 997 turbo prices so low it may be time to buy my second.

Can I ask what your suspension settings are?

My best guess is that you don't have the car setup right. And the fact you ignored my post kind of shows it.

[dans135i]

Originally Posted by Suds

Just because a 911 with a rear engine, that has been tweaked through like 4 generations and 50 years dosen't make it a good design. You can polish a turd and make It shinny.

And yes I have owned a 911, but with the 997 turbo prices so low it may be time to buy my second.

4 generations? 50 years? Sorry, my 73 911 is competitive w/ moded GT3's , Moded Caymans as well (AX) , running said struts/design. A statement like that regarding the handling/design of a 911 shows you 'only' owned one. "The 911 divided the world into those who could drive , and the rest"...

Sorry, now back to your regular programming...https://sharesync.serverdata.net/Web...5zaxZAOXkWlC6s

[dans135i]

Agreed. Just had to say something when someone calls the winning-est marque in history a turd...

[Suds]

I am actually planning to go to the Porsche Stuttgart museum tommorrow, I won't mention the turd thing, as a design engineer, sometimes designs have to ferment to achieve their best results.

[Ganicki]

Originally Posted by fe1rx

Clearly we need to step back even further:

1) brake in a straight line
2) release the brake as you turn in
3) turn in smoothly
4) maintain a balanced throttle to the apex
5) don't add throttle until you start unwinding the steering
6) add throttle smoothly
7) if you are overcome by the urge to spend money on your car, modify your car per Kgolf's list, starting at the top pausing to check the results whenever you run out of money

Sorry to have taken your bait. I knew you really didn't want to hear the answer.

Well, the weekend was a blast, learned a lot, NCM Motorsports Park is awesome and long-- 23 turns-- got consistently faster and faster--Instructors were great at guiding and even got confused on the course-- I have a long way to go before I'd do any other mods to the 135i. Have a lot of other elements of HPDE to pick up and perfect before I start spending money.

fe1rx thats everything I heard from my instructors after 8 sessions it was all starting to sink in-- Thanks

The image below is from turn 19 into the sinkhole and yes, that is the angle of descent-- map is upside down because the Pit out is at turn 1B

[John_01]

Good to hear you had a successful day. The track layout looks like fun. Were there many BMW drivers?

[Ganicki]

Originally Posted by John_01

Good to hear you had a successful day. The track layout looks like fun. Were there many BMW drivers?

About a third of the field were BMWs. Think we had close to 165 including instructors