|
|
|
|
|
|
BMW Garage | BMW Meets | Register | Today's Posts | Search |
|
BMW 3-Series (E90 E92) Forum
>
STILL understeering at limit - there is more in the car I know it
|
|
07-04-2011, 12:22 PM | #45 | |
310
Rep 15,745
Posts |
Quote:
My first experience with the car really pushing it (mind you I did some PCA racing with my former shop before getting this car) was messing with someone with a Z3M on I-80 out here after leaving morristown BMW (had to get my blackline tailights ) We went at it several times, the older guy driving the Z had never seen a 335 before and wanted to see how it stacked up. We went and covered 20 miles of highway in about 12 minutes. For those of you who live in NJ, know that I80 heading towards the GWB splits into express and local lanes. The two of us booked it for the express and there is this sharp left sweeper, that ends up being REALLY short at 120+. So I start hauling in on the brakes, well in advance of the turn, cut the wheel in and...... nothing. It did EXACTLY what you just mentioned...it turned a little, the RFTs barked in protest and it understeered......immediately had my foot off and contrary to what most would do, I wound the wheel OUT, letting the car travel even closer to the outside wall. My friend in the car with me puckered his ass up and was just screaming 'oh shit oh shit oh shit'. The car finally regained some grip, but I had to stay off the gas completely in the turn.....as the speed bled off (down to below 40) they started to come back, but still howling in protest of what they were being subjected to. I attribute this to the lousy grip of the RFTs, as once they are sliding they do not come back. If this car was able to do away with the 'soft-lift' I could have corrected it in my usual way and exited the turn (as an experienced driver would have been able to do), but at that point I was merely along for the ride and praying to God that I didnt run my brand new less than 800 miles sedan into the barrier. And what of the Z3M? Well my friend and I still had our eye sight, and between me trying to track out without hitting anything, I watch this guy dive into the turn, it hangs the ass out slightly, does this 'wiggle', and it squats and is gone. I later caught up with him at the GWB and I pulled up next to him, to find out he was an SCCA instructor . I should have asked him if I could sign up for lessons So my point in this whole story is, know your car and make yourself a better driver. I had only one of these points covered (the better driver part, and Im not saying Im the best), and not knowing my car and how it handled almost cost me it not to mention possible injuries to me and my passenger. The other thing is tires. Tires help tremendously. Once I chucked the RFTs and went to some stickier tires (Toyo T1Rs), yes turn-in was not as sharp, but I was able to take the same turn some 9 months later with exactly the same entry speed and it held beautifully through the turn. |
|
Appreciate
0
|
07-05-2011, 02:28 AM | #46 | |
Private First Class
6
Rep 161
Posts |
Quote:
You are on point and this is what I was taught during my HPDE classes. Personally I think understeering is all relative to speed, acceleration and grip. When I was going into a turn too fast the car understeered like crazy. When I went in a little slower and keep my foot on the gas to keep traction on the back tires I blew threw the turn and was able to keep it tight. You have to be very smooth with your hands because any abrupt movments will unsettle the car. Quick hands are for stunt driving and smooth hands are for racing. Driving on the road and track are two different worlds. I never knew what my car could do until I went racing. The turn im talking about is at 3:36 and please watch in 720HD Last edited by Yankees 2010; 07-05-2011 at 02:45 AM.. |
|
Appreciate
0
|
07-06-2011, 12:04 PM | #47 |
Fast In, Slow Out
40
Rep 586
Posts |
What a super thread. I've probably read this thread 8+ times in attempts to understand what issues DaFish had and what THE HACK and e90pilot where trying to say. I thought I understood, but I didn't have a clue how much I didn't know.
Without putting time in at a track, I couldn't fully appreciate what they were saying. I was obsessed, with the help of the "enablers" on this board, to mod the brakes and suspension. M3 bits, coilovers, rear sub-frame bushings, BBK, etc. For what? I was thinking this would help with driving canyons and backroads. What a misjudgment on my part. Driving on the track is where it is at. I have little desire to drive fast on streets and freeways now a days. After participating in a HPDE school, most of my car modification ideas have gone out the window now that I have a better understanding of what the car is capable of versus what I'm capable of as a driver. The smoother I was, the faster the car could go. Learning how to be smoother and what not to do helped me appreciate the car in (almost) stock form. Aside from wider tires, 245(F)/265(R), my car is bone stock and, as a first timer, was acceptably quick. I really think the 245s on the front made a BIG difference over a 225 or 235. Notice the M3's come with a 20mm stagger versus the 30mm stagger on the regular 3ers with the Sport Package. From driving at the track, I started to understand the reasons for the modifications and that driving technique could compensate for some shortcomings. Modifying the car reminds me of buying golf clubs. Is it the Indian or the arrow? Not to knock anybody here, but my epiphany from driving school was the amount of improvement of the car can be best realized with improving the driver first. I still have a bunch of parts waiting for install, but my rush to install has tapered.
__________________
: Ken
|
Appreciate
0
|
07-06-2011, 01:03 PM | #48 | |
Major
99
Rep 1,050
Posts |
Quote:
BTW. Your suspension, chassis and BBK mods will be well appreciated as you get better and better. They weren't a waste at all. |
|
Appreciate
0
|
07-06-2011, 03:08 PM | #49 | |
Fast In, Slow Out
40
Rep 586
Posts |
Quote:
__________________
: Ken
|
|
Appreciate
0
|
07-06-2011, 05:27 PM | #50 |
Midlife Crises Racing Silent but Deadly Class
1821
Rep 5,337
Posts
Drives: 2006 MZ4C, 2021 Tesla Model 3
Join Date: Oct 2007
Location: Welcome to Jamaica have a nice day
|
The way *I* see it...
These newer BMWs (heck BMWs since the lat 1980s) have such high limits that the ONLY way that any of its limitations in terms of handling can be experienced on the street, is if you do something WRONG. Heck my 1991 318is can be made to understeer or oversteer if I drive like a completely noob or idiot on the street, but I couldn't get it to understeer or oversteer at the track because, well, it's got far more mechanical grip than power (and speed) if I were to drive it FAST. Even the mighty E9X M3, the ONLY place where you can potentially drive it hard enough to find the actual limit where it understeers or oversteers is AT THE TRACK. If you managed to get either while driving it on the street, you're doing something wrong. And I'm not against mechanical improvement. Far from it. I believe that as your skill start to improve, you will continue to put more stress on various parts of the components of the suspension, and that additional stress needs to be alleviated with beefier components or stiffer suspension or adjustable shocks or swaybars. It's a simple fact that the "harder" you drive your car the faster it wears. I'm a huge proponent of replacing factory parts with parts engineered to absorb more of the rigors and stress of performance driving. But, as you all know, I'm also fond of saying that, if you're only capable of taking advantage of 1/10th of the car's actual performance, whether you know it or not, you can double the performance of the car and you'll only really be able to take advantage of 1/10th of the increased performance. If you can take advantage of 9/10th of the car's actual performance, then doubling that performance you're actually getting 9/10th of your investment in return. So here-in lies the rub. I used to work in the aftermarket performance parts industry so I understand the vast majority of "our market" comes from people like most of you here on this board. If ONLY those that can fully take advantage of a performance mod buys performance mods, well, I'd be out of a job a lot sooner. So I'm not saying don't buy sways or coil-overs or whatever to address what you think might be understeer or oversteer. I'm saying, that once you buy it, find out what exactly it is by going to a local track to really experience it. You'd be surprised at how "neutral" these cars are before the limit kicks in. One last parting shot. I can almost guarantee you that, by adding another 1.5 degrees of negative camber up front, you'll actually get BETTER result than going to a wider tire. A 225 wide tire on -2.5º of camber will likely grip and perform better than a 245 wide tire on -0.7º of camber up front. And this is why the M3 control arms seems to make such a dramatic difference in handling, not because it's the M3 control arm, but because it adds anywhere from 0.5-0.7º of negative camber up front.
__________________
Sitting on a beat-up office chair in front of a 5 year old computer in a basement floor, sipping on stale coffee watching a bunch of meaningless numbers scrolling aimlessly on a dimly lit 19” monitor.
|
Appreciate
0
|
07-06-2011, 08:21 PM | #52 | |
Major
156
Rep 1,288
Posts
Drives: 2014 435iX, FBO
Join Date: Mar 2009
Location: Ontario, Canada
|
Quote:
__________________
2020 M2 Competition HS, DCT, 763s, Carbon: splitter, side skirt, grill, diffuser, wing
Previous: 2014 BMW F32 435iX - JB4, MHD Flash, BMS Meth Kit, ER Intercooler, intake, catless DPs, KW Streets, 437M Reps with 245/35 and 275/30 Michelin PSS 4S |
|
Appreciate
0
|
08-03-2011, 08:23 PM | #53 | |
Major
156
Rep 1,288
Posts
Drives: 2014 435iX, FBO
Join Date: Mar 2009
Location: Ontario, Canada
|
Quote:
I completely disagree with these statements. The car in it's stock form with RFTs understeers full stop. It is designed that way from BMW, all the magazine editors write about it in every article, even when discussing the M3, they say it understeers. It does. The 335 plows into corners. This is shown completely in the wet or snow at SLOW speeds. Even an noob can see and feel this plowing. HACK if you don`t feel that, then I don`t think you are driving a 335. What you described above is NOT correct. It is easy to make these cars in stock form understeer - I categorically disagree with you. Before I completed my mods and added the rear bar and LSD (I didn't have these mods since writing this post), the car had MUCH less understeer, more balance and it much more enjoyable to drive - slowly, medium, fast - and at stupid fast speed - than stock. The mods have turned a nice car into a really enjoyable car. This understeer really shows up in the wet and light snow at SLOW speeds. After I did these mods, the understeer was markedly reduced. I relate this to the geometry changes being more agreeable to the car. What ever it is, the car FEELS better. It drives BETTER, and the driver has more confidence. After the rear bar/LSD/Subframe bushings and rear M3 control arms - the car is damn near perfect. As others have said, the rear bar only finely tunes the suspension. It works. Dinan has designed this nicely. It has a slight push at the limit but on regular driving it has a beautiful balance, beautiful hold on bumpy corners, you have WAY more confidence in the car. It holds the line you put it on. The steering is tighter, firmer and almost no roll. You feel the car on balance. You feel the car rotate - this was NOT there in stock form. The LSD has delivered an enormous amount of joy exiting corners. Applying power much earlier - right after apex. The trac light comes on much less. This isnt about driving like a nut. It is simple in these cars with the torque to get the trac light come on in a corner. To be able to now accelerate and DRIVE out of a corner with gusto and on balance is exhilerating. The car now powers onto the line you have selected. If I reduced the stagger to 20mm, or square setup like I have with my winter tires - the car will be PERFECT. I know it, and I will experience that when winter comes. Anyway, this is my experience with my mods. I finally have the car I wanted to have and drive 3 years ago. Track time is next (I may need a second oil cooler....)
__________________
2020 M2 Competition HS, DCT, 763s, Carbon: splitter, side skirt, grill, diffuser, wing
Previous: 2014 BMW F32 435iX - JB4, MHD Flash, BMS Meth Kit, ER Intercooler, intake, catless DPs, KW Streets, 437M Reps with 245/35 and 275/30 Michelin PSS 4S |
|
Appreciate
0
|
08-07-2011, 02:56 AM | #54 | |
Supreme Allied Commander
3841
Rep 54,348
Posts
Drives: F80 M3
Join Date: Mar 2007
Location: Santa Barbara, AP, Brembo, GIAC, Koni, Ohlins, Performance Friction, www.hpautosport.com
|
Quote:
Dinan's suspension package most likely come with a spring rate that is way too soft in the rear vs the front. With so much body roll in these cars you really need -3 of camber or further limit body roll for the front end to bite. |
|
Appreciate
0
|
08-07-2011, 03:04 PM | #55 |
Freight Dawg
102
Rep 2,103
Posts |
I disagree with you there Harold. Yes the Dinan springs are soft in the back, but they did it that way because of the wheel/tire combo they had. They tuned the package with 265/275 tire width. I still believe that a 3500-lb car that has only 200hp needs more than 225 up front if it has 255s in the back. They only way you can get that setup to handle right is to make the rear super stiff which just throws away all that grip you have back there. Maybe in may car that's not really a huge issue, but in a 335 with street tires and no LSD that's gonna create some traction issues.
Dinan's setup without changing stagger I think exacerbates the understeer problem because now the front is stiffer with a huge sway bar on those same tires. Every time you turn the wheel you're asking a very small contact patch to way to much way too fast. I'm only talking from the experience I've had with my car. The one thing I did that made the biggest difference was the stagger. I bet if you just had a square setup on a stock ZSP car, it would be decent.
__________________
--Marcelo
'06 Arctic Metallic 325i | Sport Package | 6MT | Dinan Stage III suspension | Dinan exhaust | 330i manifold swap! Click here! | Active Autowerke tune | 135i Brake Calipers | Deiselboost caliper brackets | E46 M3 front rotors |
Appreciate
0
|
08-07-2011, 04:21 PM | #56 |
Major
99
Rep 1,050
Posts |
CAMBER!!!!! That and a square tire setup are the 2 biggest suspension upgrades you can do.
Spring rate and sways that aren't balanced for the whole suspension and tire package and more importantly the driver's purpose for the car are issues also. |
Appreciate
0
|
08-07-2011, 04:57 PM | #57 | |
General Nuisance in a Private Conveyance
77
Rep 1,907
Posts
Drives: like it's rented
Join Date: Nov 2008
Location: behind the wheel
|
Quote:
That was the very first mod I made and it has made quite a bit of difference, overall.
__________________
BMWCCA Member # 414198 |E90|SGM|6MT|Premium|Cold|Sport|Tint|LCI MSport Conversion|MTech|Blacklines|219M|PSS|Quaife|Helix FMIC|M3 Suspension|Megan Racing|GC Camber Plates/Coilovers|Eibach 440/800#|AR Catted DP|Cobb AP|StopTech Drilled/Slotted|SS Brake Lines|DWS Quaife Review: http://www.e90post.com/forums/showthread.php?t=311570 |
|
Appreciate
0
|
08-08-2011, 11:26 AM | #58 | |
just another bmw douche bag
195
Rep 3,640
Posts |
Quote:
BMW does this to make the car understeer in the hands of novice drivers. running a square tire setup is an easy fix for those that don't want to mess with changing spring rates and sway bars - which can be construed as throwing on a big rear bar just because the car understeers, instead of figuring out why it's understeering first. |
|
Appreciate
0
|
08-08-2011, 05:59 PM | #59 |
Freight Dawg
102
Rep 2,103
Posts |
I think you missed my point. If you buy anyone's coilover package, it's not going to handle correctly if you don't have the complete setup. What I was saying is Dinan tuned their suspension a certain way. If you don't match what they did (i.e. 10mm of stagger) it's not going to handle like as it was intended. If you sart messing with different spring rates and bars and what not, you're really say you know more than Dinan. Which is all fine and dandy but in that case you shouldn't spend your money on them as they are pricy as we all know.
__________________
--Marcelo
'06 Arctic Metallic 325i | Sport Package | 6MT | Dinan Stage III suspension | Dinan exhaust | 330i manifold swap! Click here! | Active Autowerke tune | 135i Brake Calipers | Deiselboost caliper brackets | E46 M3 front rotors |
Appreciate
0
|
08-08-2011, 07:54 PM | #60 | |
Major
156
Rep 1,288
Posts
Drives: 2014 435iX, FBO
Join Date: Mar 2009
Location: Ontario, Canada
|
Quote:
From Car and Driver: "Also add $5399 for 19-inch forged wheels—they weigh just 20 pounds apiece—plus Michelin Pilot Sport PS2s (265/30 front, 275/30 rear). These mods make turn-in substantially more eager, and those front tires—40 millimeters wider—effectively squelch understeer. Hold on for 0.99 g on the skidpad—that’s superior to any M3 we’ve tested—and be ready to countersteer when the rear end comes around, jauntily." I don't like the old rims they sold, but they have come down a lot. The new ones look nice, but they are $6k + tires again.. wow. Nice and light though. I wan to find the offsets on the new Dinan rims/tires so that I can put that out to the vendors and get some options. I don't want spacers. Last edited by DaFish; 08-08-2011 at 08:02 PM.. |
|
Appreciate
0
|
02-16-2012, 10:14 AM | #61 | |
Lieutenant Colonel
102
Rep 1,903
Posts
Drives: e92 335i 6MT
Join Date: May 2011
Location: Toronto
|
Quote:
Btw, the Dinan rims are on "sale" for $3509 right now |
|
Appreciate
0
|
02-16-2012, 11:22 AM | #62 | |
Supreme Allied Commander
3841
Rep 54,348
Posts
Drives: F80 M3
Join Date: Mar 2007
Location: Santa Barbara, AP, Brembo, GIAC, Koni, Ohlins, Performance Friction, www.hpautosport.com
|
Quote:
Front camber wasn't addressed. Throw some camber on there and you will reduce the understeer without having to run a square setup. Square setup allows rotation and longer tire life, but you are not really addressing the what is really cuasing the understeer. In our testing, we found the larger front bar reduce understeer to a certain degree, but more static and dynamic camber is the key. |
|
Appreciate
0
|
02-16-2012, 10:14 PM | #63 |
Lieutenant
30
Rep 468
Posts |
And after more camber in the front then go to a square setup. I ran 255's front and 275's rear last year with -3.2camber front and -1.5 rear with many suspension mods and still didn't have enough front grip. Can't fit bigger than 255 up front so I am going to 265's in the rear.
I kept taking camber out of the rear last year and adding front and still couldn't get the perfect balance. Even played with the corner weighting of the car to try to get more rotation. Went back to the stock rear sway bar as with the stock diff and 450wtq inside tire spin is a huge issue on corner exit. |
Appreciate
0
|
02-16-2012, 11:39 PM | #64 | |
Supreme Allied Commander
3841
Rep 54,348
Posts
Drives: F80 M3
Join Date: Mar 2007
Location: Santa Barbara, AP, Brembo, GIAC, Koni, Ohlins, Performance Friction, www.hpautosport.com
|
Quote:
If you have compression damping adjustments, try one more click on the front to give the front tires more load. Toe can also play a role here so have a look at that. I also mentioned dynamic camber, your camber may very well be at -3.2 static, but what is it at dynamic? |
|
Appreciate
0
|
02-17-2012, 06:41 AM | #65 |
Lieutenant
30
Rep 468
Posts |
Tire temps indicate that -3.2* is reasonable in the front given what I put the car through.
I am running AST 4100's so only rebound adjustability, but have gone through a few different iterations of the valving with my local shop all of which have made positive changes. Depending on what kind of driving I am doing in what time frame the alignment changes regularly. I typically run .1* total toe in front as less than that tends to eat tires quickly. I run .14* total toe in rear which any less makes the car really twitchy at high speed. There is no way of measuring dynamic camber without some serious equipment as you know so that is out of the question. The car is not very low however and by the evaluation of the suspension at my current ride height I am not in the danger area of poor geometry for a macpherson strut equipped car. I think my main issue is really the need of an aftermarket LSD, but given mine is welded the expense is quite great as you guys know. Not running any deals currently are you? |
Appreciate
0
|
02-17-2012, 10:40 AM | #66 | |
Lieutenant
31
Rep 595
Posts |
Quote:
1. while the car is still on the ground, measure the distance from the center of the wheel to the top of the fender arc 2. put the car on jack stands, make sure the car is leveled 3. remove wheel, remove the spring only, disconnect the swaybar 4. put the wheel back on 5. use the floor jack to compress the suspension to the distance you measured in step 1 6. measure the camber, this will be your static camber 7. continue to compress the suspension, stop at every 1/2" or so and measure the cambers, these numbers will be your dynamic camber 8. stop until the suspension is fully compressed This is a simple way of measuring when you don't have the sophisticated equipment.
__________________
|
|
Appreciate
0
|
Bookmarks |
Tags |
sway bars, understeer |
|
|