Sway bar upgrade and sticker tires?

[Greg FEightytwo]

Went to thunder hill for the 2nd time and struggling behind Porsches. I know the gt3 comes with cup2 tires but they stay pretty flat through off camber turns. I have edc springs and spacers and I'm wondering if I put cup2s and h&r sway bars to keep the car flat if that would help respond better?

Full coils are not an option as I hate coding....

Are there camber plates yet?

[MaynardZed]

Originally Posted by Greg FEightytwo

Went to thunder hill for the 2nd time and struggling behind Porsches. I know the gt3 comes with cup2 tires but they stay pretty flat through off camber turns. I have edc springs and spacers and I'm wondering if I put cup2s and h&r sway bars to keep the car flat if that would help respond better?

Full coils are not an option as I hate coding....

Are there camber plates yet?

Gonna be a little slower than GT3s, drivers being equal. Should be faster than most other street Porsche.

Yes, of course, stickier tires will help a lot. The PSS aren't very good IMO for the track if that's what you are still using.

Turn-in is a little lazy on the M4, have to get ahead of the car and turn a little sooner than you'd think. I haven't tweaked with the stock alignment, but a little bit of toe-out in the front should help.

Sways might help roll a bit, but the M4 actually needs a softer sway in the rear to help get power down on corner exit. If you're going get them, I'd just do the front.

No confirmed workable camber plates for stock suspension as of yet. Someone here ordered the ones from Turner, but no go as they don't work with the strut brace without heavy fab.

[brian99997]

still no camber plates for adaptive..

this car isn't going to keep up with 991 gt3's on comparable tires, especially if he has cup2's (180 tread) vs our super sports at 300... I had some data from my gt3 on pirelli corsa system's being 2 seconds slower than hoosier r6's on a 1:20 sized track and I always felt the corsa systems were faster than MPSC's so you could buy maybe 4 seconds total there?

I'm going to drive on r6's this weekend, all else besides brakes stock and see if I can get some data for us.

The super sports are almost in need of sway bars, but we need camber even more.

[brian99997]

Originally Posted by MaynardZed

Turn-in is a little lazy on the M4, have to get ahead of the car and turn a little sooner than you'd think. I haven't tweaked with the stock alignment, but a little bit of toe-out in the front should help.

I'm going extra toe in for the back to help the car straighten up under power and a tiny bit of toe out for the front this weekend. will update everyone on the results.

To me, a sway bar removes traction from that end of the car.. so a softer rear bar will make the car push, as will a harder front bar.

[Greg FEightytwo]

Pss tires. They totally suck. Great street tire. They squeal and brake loose on off cambered turns. I got a 2:20 thunder hill and people are getting 2 flat. Lol. 2:10 is average from what I heard but I look at my video and there's from driver view and I feel like I bought the wrong car again. Lol

[Greg FEightytwo]

Thank you guys for jumping in with information. I'm going to try the cup 2s when these pss are toast

I have 0 toe and -1.7 front and -2.3 rear btw

[MaynardZed]

Originally Posted by brian99997

I'm going extra toe in for the back to help the car straighten up under power and a tiny bit of toe out for the front this weekend. will update everyone on the results.

To me, a sway bar removes traction from that end of the car.. so a softer rear bar will make the car push, as will a harder front bar.

Agree with your first point 100%

Not been my experience for your second point. A softer rear sway should load the outboard rear tire more on corner exit (acceleration) adding to traction. My E36 track car's rear sway is removed actually and stiffer one put up front. If it feels like it's pushing just add throttle and the rear squats and it grips like mad. This is a setup introduced to me by my race mechanic / instructor and it definately works on the E36. We've just begun experimenting with the M4, but the principles should be the same we hope?

[Greg FEightytwo]

Originally Posted by MaynardZed

Agree with your first point 100%

Not been my experience for your second point. A softer rear sway should load the outboard rear tire more on corner exit (acceleration) adding to traction. My E36 track car's rear sway is removed actually and stiffer one put up front. If it feels like it's pushing just add throttle and the rear squats and it grips like mad. This is a setup introduced to me by my race mechanic / instructor and it definately works on the E36. We've just begun experimenting with the M4, but the principles should be the same we hope?

I heard the same thing .. Lighter rear sway and stiffer front helps. I saw a post to see what the diameter of the bars are and no data yet for that. I think the e92 m3 was 28mm and a 20mm rear. The H&R one is 30mm and 25mm not sure how it would behave with that set up.

[FTS]

It may be misleading to compare A/R bar rates based solely on outer diameter of the bar; generally modern cars use hallow bars for reduced weight, so to do a proper comparison, you would need to also know the inner diameter of the A/R bars. I obviously do not have that info on the F8x

[brian99997]

A corner has at least 3 points right, entry, mid and exit. Sway bars affect mostly only the entry and exit as the springs basically hold the middle although the bars contribute still.

A stiffer front bar will reduce off power steering on entry mostly

A softer rear bar will decrease on power steering on exit, which will hopefully not be needed after I test various toe angles this weekend.

I can explain the actual physics behind how it overloads the outside tire, but this wiki article is a fantastic shortcut to the simple facts http://en.wikipedia.org/wiki/Racing_setup

The H&R's offering 30/25mm with 2 holes on the front and none on the rear.

RD seems to make 32.2 and 25.4mm hollow with 25 adjustment steps claiming between 13% and 33% stiffer than stock. $520 for both with bushings. Interestingly they have an e9x diagram up, but they're claiming at 1" the stock bar is 200lbs up to 480lbs at 2" yet their bar is 320lbs at 1" to the same 480lbs at 2" meaning the bar is not as progressive and starts off harder. http://www.rdsport.com/store/f8x-m3-m4-sway-bars.html

Cornering is different to every driver, having a decently adjustable set is the way to go so you can try it for yourself.

[MaynardZed]

Cool Wikipedia chart. I agree with most of it, but for setting up the E36 (and M4 maybe) removing the rear sway works. My race mechanic has 20 years experience racing and setting up these cars for racing. Its funny he acts like its some sort of "secret" thing to do this, but its well known in the E36 to work. Might work well with the way he teaches us to drive, slow-in fast-out. Typically you'd be back on the throttle well before corner apex which helps the car turn even better.

I really don't know why it works so well. I don't think he really does either, but it does. Keep us posted on your setup changes for the M4. Hoping you switch tires first and maybe add the sway bars at a later time. Sometimes when making multiple changes hard to know what's doing what.

[Vectors2final]

With the car being lowered, I probably wouldn't do sways without endlinks. I probably won't until that solution is available.

I'd prefer to have endlinks with the car lowered, anyway, but hey...

[Jim Gianatsis / QWK M4]

I love my M4 too!*Equipped with DC 7-Speed, Brembo Composite Brakes, Active Suspension. And the Harmon-Kardon Optional audio is a must as it sounds great, and you can digitally download, store and play all your music with no loose CDs in the car.

• Actual power output is 480hp, not the 425hp as factory rated.
Plug-in performance upgrade computer modules available from Dinan or Turner Racing take power up to 520hp. Actual dyno tune remapping can get it up to 600hp as you'll see in other videos on YouTube.com.

• I wanted to give you some feedback on increasing the tire sizes on the M3/4's OEM stock M3/4 9x19 Front, and 10x19 Rear Wheels.

The stock Michelin Pilot Sports at 255F / 275R are too narrow for a car with this much power and braking force, especially with the optional Brembo Carbon Composite Brakes.

I had wanted to go to wider rims to match changing to wider tires. But wider rims also add more unsprung weight which cancels any perceived handling gain. Changing to expensive forged wheels would be lighter, but no one is making forged wheels in 0.5" wider than stock sizes.

All the current Forged applications for M3/4s are 10x19 front, and 11x19 rear, and to be honest this setup looks stupid on the car (especially with stock or just 1-size wider tires, and it still adds back more rotating and unsprung weight. So I'm just sticking with the stock M wheels for now and not wasting $4,000 for 1' wider forged wheels that end up not being much lighter, and don't really improve handling (especially with stock width size tires).

So, I moved the stock rear 275s tires to the Front 9x19 stock wheels, and added new 295/30s tires to the stock 10x19 Rear Wheels. This is an approved fitment from Michelin for these wider tires on the stock width wheels. I actually found the 295/30x19s at my local America's tire Store for just $275 ea, far cheaer than mail order from Tire rack. And America's did all the tire switching and balancing very affordably.

My M4 now looks, handles and sticks so much better with this tire change.
You can certainly go to sticker Michelin Pilot Cup or other Street Legal Track Tire,
but for a regularly driven street car, just his affordable change with just (2) wider Pilot Sports is the best choice for 99% of the cross country, street and canyon driving we will be doing.

• I had also pre-orded H&R springs to lower and stiffen it up, but when the car arrived and I drove it, it handles so well and corners so flat, I see no need to change the springs. I would like the lower agressive look, but on my old M3 which had the H&R springs installed, on the street the underside bottomed on speed bumps, the front end ground on driveway and shopping center entries and exits, and the suspension bottomed out on road bumps when carrying passengers. So I'm just going to leave the awesome original suspension and ride height stock for now.

Just so you know, I am a former Sports car Club of America B Prepared regional class champion in a Trans-Am Camaro, and a professional race car test and development engineer.

You can see my car pictures here on Facebook - https://www.facebook.com/media/set/?...1&l=9369dfd153

[MaynardZed]

Thank you Jim. I like your FB page, there seems to be common theme in many of your pictures that I approve of.

Have you driven the M4 on track yet? My race mechanic / instructor drove mine on track and said it felt almost like driving a V8 powered stock car with all that torque. He's the one suggesting to me it needs a softer rear sway to help get traction down on corner exit.

[Greg FEightytwo]

Harold at hpautoworks is building a set of camber plates. No ETA but I think I'm going to do those and at least the front sway with the cup2s.

[MaynardZed]

Originally Posted by Greg FEightytwo

Harold at hpautoworks is building a set of camber plates. No ETA but I think I'm going to do those and at least the front sway with the cup2s.

Keep us posted

[Greg FEightytwo]

26mm front.

23mm rear for f82

[kitw]

Originally Posted by Greg FEightytwo

Pss tires. They totally suck. Great street tire. They squeal and brake loose on off cambered turns. I got a 2:20 thunder hill and people are getting 2 flat. Lol. 2:10 is average from what I heard but I look at my video and there's from driver view and I feel like I bought the wrong car again. Lol

You just started going to the track. Just ease into it and learn to go fast - the F80 is good for low 2:0x at thunderhill stock, so once you can do that look into changes. Sway bars alone make the car feel faster but often times don't increase grip at all. You go faster because you feel more confident but the car isn't any faster. First step is race brake pads, second is tires (and possibly wheels to stop eating up your expensive street tires) and then coaching to get fast. Took me a year of every other weekend to get reasonably fast, and a years to get consistent. Your car still has a lot left in it.

[Greg FEightytwo]

Originally Posted by kitw

You just started going to the track. Just ease into it and learn to go fast - the F80 is good for low 2:0x at thunderhill stock, so once you can do that look into changes. Sway bars alone make the car feel faster but often times don't increase grip at all. You go faster because you feel more confident but the car isn't any faster. First step is race brake pads, second is tires (and possibly wheels to stop eating up your expensive street tires) and then coaching to get fast. Took me a year of every other weekend to get reasonably fast, and a years to get consistent. Your car still has a lot left in it.

Hey Kit

I ordered the 30mm sway.. I'm getting cup2s and see what that does for me. I have access to coaches so that is my next step. When are you gonna come out with us?

[kitw]

Originally Posted by Greg FEightytwo

Hey Kit

I ordered the 30mm sway.. I'm getting cup2s and see what that does for me. I have access to coaches so that is my next step. When are you gonna come out with us?

sometime soon. next time I'll be at the track will be at the lemons race in March.

[lutfy]

Originally Posted by MaynardZed

Agree with your first point 100%

Not been my experience for your second point. A softer rear sway should load the outboard rear tire more on corner exit (acceleration) adding to traction. My E36 track car's rear sway is removed actually and stiffer one put up front. If it feels like it's pushing just add throttle and the rear squats and it grips like mad. This is a setup introduced to me by my race mechanic / instructor and it definately works on the E36. We've just begun experimenting with the M4, but the principles should be the same we hope?

Softer bars on all of these past chassis. However, for E36, the camber curves were very different than the current gen cars. For instance the E9x no where near required the crazy 3+ degrees of front neg camber. A bigger front bar on McPh strut cars actually help. Think less roll hence less camber loss. This more than offsets the 'stiffness induces understeer'; which is true if the car was independently suspended and camber curves were spot on.

Bigger bar on these cars with stock rears actually help.

Cheers,

Lutfy

[MaynardZed]

Originally Posted by lutfy

Softer bars on all of these past chassis. However, for E36, the camber curves were very different than the current gen cars. For instance the E9x no where near required the crazy 3+ degrees of front neg camber. A bigger front bar on McPh strut cars actually help. Think less roll hence less camber loss. This more than offsets the 'stiffness induces understeer'; which is true if the car was independently suspended and camber curves were spot on.

Bigger bar on these cars with stock rears actually help.

Cheers,

Lutfy

We have a huge front sway on the E36 and none in the rear FWIW.

I agree, a bigger front sway on the F8X is a good idea, I just think a stiffer rear sway is not in order considering how tail happy it is already on thottle up / corner exit.