E92 M3 ZCP in SCCA Solo F Street

[Rassilon]

Hi guys,

I am an autox intermediate/novice who is switching from a turbo fwd to e92 m3. I am still learning the car, but I am constantly getting killed in high speed sweepers because I am afraid the car is going to spin on me with more throttle, compared to wot in a fwd car . I am curious what does the car feel like if you give it too much gas during the sweepers @70+mph. If I am smooth with the throttle would it be a progressive rotation from rear? Or a relative quick one? Also for slalom, do you guys use the rear to help you rotate by modulating the throttle? Or it's better to be constant throttle and smooth quick left and right steering?

Thanks for any suggestions.

[z3papa]

Coming from a very short wheel based roadster, provided you have smooth inputs, the M3 is extremely stable at the extremes and counter measures are very predictable.

[Rassilon]

Originally Posted by z3papa

Coming from a very short wheel based roadster, provided you have smooth inputs, the M3 is extremely stable at the extremes and counter measures are very predictable.

By counter measure, you mean if I gave too much throttle during sweepers, just lift 50%, counter steer a bit then slow back on to the throttle?

[z3papa]

By counter measures I rarely suggest lifting just as the rear is letting loose. I tend to implement a catch when the car is stepping out oversteer to prevent the rear from coming around. In my old Z, the only way you could be fast was to keep your foot into and modulate the tendency to snap in high speed sweepers.

[CSBM5]

You need to build up experience controlling a powerful RWD car I guess. You could easily spin the car, like many other cars, if you're not "ahead" of the car in your thinking/vision/feeling/plans. However, the M3 is incredibly controllable in situations like you've described with excellent feedback through the wheel and seat to what's going on.

Do you have any experience controlling a RWD in oversteer situations? If not, you should look into avenues to gain such I would suggest.

[Rexpelagi]

Originally Posted by edwardgtxy

Hi guys,

I am an autox intermediate/novice who is switching from a turbo fwd to e92 m3. I am still learning the car, but I am constantly getting killed in high speed sweepers because I am afraid the car is going to spin on me with more throttle, compared to wot in a fwd car . I am curious what does the car feel like if you give it too much gas during the sweepers @70+mph. If I am smooth with the throttle would it be a progressive rotation from rear? Or a relative quick one? Also for slalom, do you guys use the rear to help you rotate by modulating the throttle? Or it's better to be constant throttle and smooth quick left and right steering?

Thanks for any suggestions.

Honestly you would have to be pretty aggressive with the throttle on decent tires to make the car oversteer on throttle, at least at 70mph (in 3rd at that point). Lower grip tires will obviously make it happen faster.

The key is to always know your exit point. For example, if you were on track with a simple 180, it would be the outside of the course after the 180. What this allows you to do is feed in whatever steering is necessary without much thought. Keep your eyes on your exit and steer there. You shouldn't be looking at your apex after turn-in really. Basically - look ahead. If you do this, you'll be fine. It takes a lot of practice though. If you can do that with smooth throttle application you really shouldn't have an issue. The car doesn't really make much torque so it isn't as hard to drive as some others with similar power numbers.

Regarding slaloms - I struggled with this coming from other cars and still do if I'm not focused. From my experience the M3 with the differential and quick steering does not like to be thrown around. My Mustang doesn't care - that's the fast way to drive it. If you try to do that in the M3 it will try to spin. The best thing to do is keep it tight and tidy with constant throttle input (very slight, generally).

[Rassilon]

Originally Posted by CSBM5

You need to build up experience controlling a powerful RWD car I guess. You could easily spin the car, like many other cars, if you're not "ahead" of the car in your thinking/vision/feeling/plans. However, the M3 is incredibly controllable in situations like you've described with excellent feedback through the wheel and seat to what's going on.

Do you have any experience controlling a RWD in oversteer situations? If not, you should look into avenues to gain such I would suggest.

I don't have previous oversteer correction experience aside from sim games, and I have been playing around with the throttle during slow turnaround in autox to get a feel of the car and rear getting lose.

After spinning off course @80mph last week, coming out of the slalom toward the finish line and hit a small surface gap , I become very scared of the car in high speed sections. I hope I can slowly rebuild confidence and improve my skills as I get more seat time autoxing the m3.

[Rassilon]

Originally Posted by Rexpelagi

Honestly you would have to be pretty aggressive with the throttle on decent tires to make the car oversteer on throttle, at least at 70mph (in 3rd at that point). Lower grip tires will obviously make it happen faster.

The key is to always know your exit point. For example, if you were on track with a simple 180, it would be the outside of the course after the 180. What this allows you to do is feed in whatever steering is necessary without much thought. Keep your eyes on your exit and steer there. You shouldn't be looking at your apex after turn-in really. Basically - look ahead. If you do this, you'll be fine. It takes a lot of practice though. If you can do that with smooth throttle application you really shouldn't have an issue. The car doesn't really make much torque so it isn't as hard to drive as some others with similar power numbers.

Regarding slaloms - I struggled with this coming from other cars and still do if I'm not focused. From my experience the M3 with the differential and quick steering does not like to be thrown around. My Mustang doesn't care - that's the fast way to drive it. If you try to do that in the M3 it will try to spin. The best thing to do is keep it tight and tidy with constant throttle input (very slight, generally).

Thank you for the tips! I will try those in my next events. And a quick question in terms of comparing times, how many seconds slower do you think stock PSS are compared to the best street tires like re71 or z2 on a 60 sec course in m3?

[Rexpelagi]

Originally Posted by edwardgtxy

Thank you for the tips! I will try those in my next events. And a quick question in terms of comparing times, how many seconds slower do you think stock PSS are compared to the best street tires like re71 or z2 on a 60 sec course in m3?

I'd suspect at least 1.5-2s, but haven't tested it. I have tested RE-71R vs. Z2* on another car and based on that the 71R would be about a second faster on a 60s course, so I figure the PS2 is a little slower (not sure if some M3's came with PSS? Mine came with PS2).

[Rassilon]

Originally Posted by Rexpelagi

I'd suspect at least 1.5-2s, but haven't tested it. I have tested RE-71R vs. Z2* on another car and based on that the 71R would be about a second faster on a 60s course, so I figure the PS2 is a little slower (not sure if some M3's came with PSS? Mine came with PS2).

Interesting. I saw a lot ppl running with RE-71R this year and in comparison my PSS needs at least 2-3 runs just to get up to temp =S There's another m3 driver in my region who runs with RE71R, I guess I will shoot for his time - 2 as a benchmark.

[ChezT]

Hi! Just picked up my M3 a few weeks back and ready for some dedicated AutoX wheels and tires. I ran several set ups on my last car, A RX8, ranging from Hossiers to Kuhmo Estas. I'm leaning towards a set of of Rivals right now but I can't decipher the ideal wheel and tire size. I'm leaning towards a square set up but to stay in the street class, where should I shoot for in sizing besides 18" wheels? Can I fit a 265/35/18 all the way around on 8.5/9" wide wheels?

[Rexpelagi]

Originally Posted by ChezT

Hi! Just picked up my M3 a few weeks back and ready for some dedicated AutoX wheels and tires. I ran several set ups on my last car, A RX8, ranging from Hossiers to Kuhmo Estas. I'm leaning towards a set of of Rivals right now but I can't decipher the ideal wheel and tire size. I'm leaning towards a square set up but to stay in the street class, where should I shoot for in sizing besides 18" wheels? Can I fit a 265/35/18 all the way around on 8.5/9" wide wheels?

Nice, congrats! ZCP or non-ZCP? The wheels are different, and you can't change widths. Regardless, 265/35R18 will fit square on either car (this is my current setup until my 275's come in). This size is only available in 71R.

I have no experience with the Rival on the M3 but I have driven them on other cars. They are less predictable and slower to respond, although they can be made to work. Most stock (street) cars seem to run well on 71R's.

[z3papa]

He's got a 2010 so it must not be ZCP. As such, he's on 8.5/9.5 wheels.

[ChezT]

Correct, it's a non ZCP.

To run a 265 or 275 square set up, what kind of offset will I need and still stay legal in FS?

[Rexpelagi]

Originally Posted by ChezT

Correct, it's a non ZCP.

To run a 265 or 275 square set up, what kind of offset will I need and still stay legal in FS?

Offsets need to be within ±7mm of stock, same wheel width, and ±1" diameter. I believe the factory wheel specs are:

18" style 260
Front 8.5J ET:29
Rear 9.5J ET:23

19" Style 220
Front 8.5J ET:29
Rear 9.5J ET:23

[z3papa]

With 8.5" fronts, I would probably not suggest 275's although some may have already tried them on that wheel. No problem on the rears.

[CSBM5]

As shown earlier in this thread, I have had fine results running 275/35-18 Rivals all around on 8.5/9.5 wheels. In fact, edge wear up front has been excellent with the tires slightly pinched (note the TRA recommended range for the tire size is 9.0-11.0 with 9.5 being the spec width). Just running it with a 0.5" below that spec range hasn't been any issue, and performance has been excellent.

Also as mentioned earlier, I've been using TRMotorsport 8.5/9.5 wheels which has native offsets of 44mm for the 8.5 and 35mm for the 9.5. I'm using 18mm spacers to give net offset values of 26mm up front and 17mm in the rear.

No issues with clearance in the front or rear. I would suggest running 275/35s all around.

[Richbot]

Second that. Though with the results we have I would choose re71r in the "wrong size" before any other tire. Seems like an easy button.

[Rexpelagi]

Here are my fastest runs from Wilmington:

Saturday (didn't quite get the data synced well):

Sunday:

[CSBM5]

John,

Nice work once again!! Don't you just love the S65 torque curve? How it is flat for soooo long and can therefore put down usable power in situations where a car with a fatter/peaked curve would be spinning the tires and/or requiring deft throttle management? The section toward the end of the Saturday course reminded of enjoying such...where you upshift form 2nd-3rd (catching some rubber too) and just wing it out through the rest of the course. It's one of the things (to me) that makes the E9x M3 so competitive on course.

I've also had some courses where I can just hammer the 1-2 upshift mid-element coming off the start and go with it which just amazes me during those times.

Still on those 265s?

Chuck

[z3papa]

Very nice runs John. You handed all of us our tails this weekend. By the way, in the early part of corner 1, your car definitely looked to step loose "Mr. I like my sway bar soft".

[Rexpelagi]

Originally Posted by z3papa

Very nice runs John. You handed all of us our tails this weekend. By the way, in the early part of corner 1, your car definitely looked to step loose "Mr. I like my sway bar soft".

Haha I never said it doesn't slide around. :-p. I just prefered the turn-in feel this way at the first event over the middle setting and never went back.

And yes, still on 265's. I plan to bring them to nationals and potentially run them for drys, with 275's as back-ups / wets.