07-09-2018, 06:41 PM | #89 |
Lieutenant
313
Rep 525
Posts |
Why not just save the MPSS for daily driving and get a new set of wheels for the 71Rs? This is the route that most choose as it saves cost in the long run (having multiple sets).
|
Appreciate
0
|
07-10-2018, 12:20 AM | #90 |
Lieutenant
174
Rep 400
Posts |
I already have a winter set (17") and I did not want to have another set for Auto X.
I was going to use up the winter tire this coming winter and put RE71r next spring on 17" rims and just put good all season on stock 18". Now I'm thinking just put Re71r in 17" rim right now (take out winter tires and reinstall it before winter). lol |
Appreciate
0
|
01-10-2019, 06:01 PM | #92 | |
Private First Class
48
Rep 148
Posts |
Quote:
Where do you get them? How much negative camber can you get |
|
Appreciate
1
icin235102.50 |
01-28-2019, 10:53 PM | #93 |
Lieutenant
329
Rep 455
Posts |
This is maybe a silly question, but why is the 128i generally considered to be a reasonably competitive car in STX but the 228i isn't?
As far as I can tell, the weight is about the same, the amount of tire you can fit is about the same, with similar mods they should be at similar power power levels (and the 2.0T may even have an advantage with a wider powerband)? Does the extra 1" of track width, 2" of length, (approx) 40 lbs higher minimum curb weight, and electronic vs. hydraulic steering really make that much difference? |
Appreciate
0
|
01-29-2019, 08:00 AM | #94 | |
Colonel
1219
Rep 2,030
Posts |
Quote:
|
|
Appreciate
0
|
01-29-2019, 11:47 AM | #95 |
Lieutenant
329
Rep 455
Posts |
I agree completely. The 86 Twins are almost perfect for STX and it takes a very particular kind of course layout with long straights to give the 128i an advantage. I guess I’m just confused about why all the things that make the 128i a course-dependent monster don’t also make the 228i/230i a course-dependent monster as well? Is it really just that no one has bothered to try a proper STX build yet because a stripper of a 2 costs $35k new while a used 128i is half the cost and already has some proven builds?
|
Appreciate
0
|
01-29-2019, 12:02 PM | #96 | |
Colonel
1219
Rep 2,030
Posts |
Quote:
No one has even done a "proper" 128i STX build either lol. The two people that campaigned cars successfully still used stock seats, electronic differentials, and poorly setup suspensions (imo). They ditched their cars because they were "too expensive" to run when both only did minor mods (headers and exhaust tuning). One sold his 128i to another autocrosser who made a ton more changes to the car and took 4th this year in STX. That's the gist of what I remember from the 1addicts threads anyway... Course dependent? The 128i/228i does have a superior power to weigh ratio so it will win in longer stretches. If you compare track width and wheelbase to other popular cars then on paper there is no reason to belive the car should be "course-dependent" and reliant on its horsepower to edge the competition. BMW has produced great handling cars for decades. There is just a longstanding myth that you can't get a 128i to stop under-steering. Literally every person I have ever had ask me about my 135i talks about how they "heard" that these cars are great but they understeer. It's just not true if you set the suspension up right lol. Cost is again what I would go back to as the main factor in regard to setting up a 228i. That and the available DME tuning knowledge to do things like linear throttle and 2-step. Launching makes a big difference at nationals since they do 60' drag starts. I would think the 228i would edge out the 128i. Superior torque and power curve. The 1.x" difference in wheelbase is negligible and the track width difference is non-existent when you factor in that STX cars will be running aftermarket wheels... The cars suspensions are virtually the same. 228i just has electronic steering with poor road feel but I would be willing to bet the variable sport ratios would lead to less hand movement than the abysmally slow 128 steering ratio (16:1). Last edited by bbnks2; 01-29-2019 at 01:37 PM.. |
|
Appreciate
0
|
01-30-2019, 03:08 AM | #97 |
Lieutenant
329
Rep 455
Posts |
Well...I’m planning on eventually doing most/all the “standard” STX stuff to my car because that’s where I think the sweet spot is for a streetable fast car. I’m definitely not a Nationals caliber driver though and haven’t autoXed since ‘07 on a poor high school student’s budget in an HS Ford Focus. My 230 is a stripper with only the Track Pack and ZF8A trans, so I subconsciously made it an ideal candidate for this sort of thing.
So I guess the first and most critical question is can a 17x9J rim and sticky 265mm tire fit under our tiny fenders? I’ve seen one 255mm 17x8.5Jet40 setup with a 5mm spacer up front. I’m not certain the rear would fit without poking so badly it limits suspension travel. I’ve also seen a 265mm square setup, but it was on an off-the-shelf Apex 18x9.5J setup with really goofy offsets and large spacers, maybe et30/F (after 12mm spacers) and et50/R (after 8mm spacers)? That would surely need a custom BC Forged or similar setup to replicate in a 9J without large spacers. It also had both camber plates and modified control arms and tension struts, which definitely would be illegal in STX if my understanding of the rules is correct. And that’s before you deal with the PITA of relocating the lower spring perch and swapping out a shorter main spring to gain inner clearance. Last edited by 230iZTR; 01-30-2019 at 03:21 AM.. |
Appreciate
0
|
01-30-2019, 07:21 AM | #98 | |
Colonel
1219
Rep 2,030
Posts |
Quote:
You can fit 17x9 255/265 but it's going to be with goofy offsets which makes the rear end playful. You need to run a low offset up front to clear the strut and then a high offset in the rear to clear the fender. The front track width ends up being 2" wider than the rear. You don't really want custom offset wheels because then you can't rotate... It's better to buy a high offset wheel like 17x9 ET58 and then use a 20-25mm spacer up front to make them ET38-ET33... You'll need to roll/pull the fenders to get a "true" square setup. Pretty sure that it's legal to roll/pull fenders in STX. If you flare them then you're into street prepared. Replace them and you're into street modified. Again, not too many people are pulling fenders on their luxury street cars lol Not sure what caliber of drivers there are in your local region but when I run with nationals level drivers they are top 10 no matter what car they drive lol Just go to events and enjoy the car. It's definitely not slow. Last edited by bbnks2; 01-30-2019 at 07:35 AM.. |
|
Appreciate
0
|
01-30-2019, 03:55 PM | #99 | |
Lieutenant
329
Rep 455
Posts |
Quote:
The ST* rules say only rolling the fender lips is legal. Any cutting or pulling would bump you out of the class. So I guess a truly square setup is out. |
|
Appreciate
0
|
01-30-2019, 08:04 PM | #100 |
New Member
5
Rep 18
Posts |
I am running a square setup 18x8.5et42 with 255/35/18 RE71. I am using a 12 mm spacer, and have 2.5* camber up front. No rubbing at all, so a 17x9 should fit (with spacer). When I ran Hoosier A7s at 245/35/18, the inside clearance to the strut was only about 3 mm. 255 RE71 is not near as wide. Spacer is key for interior clearance. Also using spacer when running stock staggered setup, as top of front wheels is way tucked in.
|
Appreciate
0
|
01-31-2019, 07:51 AM | #101 | |
Colonel
1219
Rep 2,030
Posts |
Quote:
|
|
Appreciate
0
|
02-06-2019, 10:18 PM | #102 |
Private First Class
48
Rep 148
Posts |
I'm running Apex 18 x 9.5 et 38 with 5mm spacer with re71r's 255/35/18 on the front. I do get rub but only when the front is really compressed.
For the rear I run Apex 18 x 9.5 et 58 NO SPACERS with 255/35/18's no rubbing at all. This year I will change the rear up a bit . Gonna mount 265/35/18 re71r's with a 8mm spacer. |
Appreciate
0
|
03-26-2019, 12:26 PM | #103 | |
Lieutenant
329
Rep 455
Posts |
Quote:
Shadow, you’re on a similar setup right? I’ll roll the front fenders, add longer stud conversion, and am open to spacers. I’m not sold on 17” v 18” but the options for 17” wheels are limited with wide tire selection, while 18” wheels are more numerous for offsets but seem to favor taller tires that make me concerned about rubbing. Apex has awesome wheels, but the announcement that they’re adding a forged line this summer makes me want to wait and really nail the wheel/tire setup. 17/18x9et42 seems to be the sweet spot for biggest with minimal rubbing on a square setup, with enough spacer to get it down to an effective et36-33. 255/35/18 or 255/40/17 is the go to for track work? Or does being lowered require going with a slightly shorter stock height like a 245/35/18? And if Apex doesn’t end up producing a 17/18x9et42 with a forged wheel, I also saw that Weds is planning to produce the TC105X in an 18x9et45 w/ 5x120 that should be darn near as strong and light as a forged wheel with their new process.Link. I’m talking sense here right? Any thoughts? |
|
Appreciate
0
|
08-20-2019, 12:08 AM | #104 | |
Private
114
Rep 87
Posts |
Lots of good experience and advice in this thread.
First time autocrossing the M240i, moderate to severe understeer the entire time, especially on higher speed sweepers. A vanilla M2 was doing quite well for its class and likely eliminated most of the soft handling issues (should have caught a ride). No LSD, Michelin Pilot Sport 4S, using basically stock tire pressures of about 36/40psi cold. Need to run in Sport Plus / possibly DSC off. About 70 degrees outside. Based on what cxp213 is saying, probably even it out to something like 32/32 or 34/34, but TajoMan implies I should try something more like 40/40. If I'm more serious, I'd start looking into the possible camber adjustments and RE71's after I wear out these tires, but for now and the next 10+ sessions the driver mod will help the most. My past experience has mainly been on very different cars like the S2000 or FWD Hondas. Quote:
Last edited by EstorilM240; 08-20-2019 at 12:23 AM.. |
|
Appreciate
0
|
08-20-2019, 08:35 AM | #105 |
Lieutenant
174
Rep 400
Posts |
With MPSS, front needed to be around 40~45 psig hot. Rear was ok around 35 psig.
PS4S may have stiffer sidewall. you should use chalk to see the wear on the side. With RE71r, I'm using 35~37 psig front, 32 psig rear when hot. |
Appreciate
0
|
08-28-2019, 01:29 PM | #106 | |
Banned
3
Rep 76
Posts |
Quote:
Last edited by MAILIYAT; 08-29-2019 at 02:41 PM.. |
|
Appreciate
0
|
09-07-2019, 08:19 PM | #107 |
Private
49
Rep 64
Posts |
For your first event. Make sure the tires are well inflated and use DSC Inactive Mode as the back end is much more controllable and doesn’t cause Sport+ boost cutting.
I’ve run my 2015 M235i AT w/225/245 std staggered at the local BMW CCA events with the stock PSS and I was running 46/44 for pressures on my surface based on the rollover. Could just be surface dependent. Idk how folks get away with low rear pressures as the rear tires end up on the sidewall and donuts ensue. I’ve been pretty close on my 3yr PSS to a 340i running PS4S by half a second or so. Thinking about getting a set of the new Yokos for the car and just occasionally running it. I do have a street class prepped s2k as well. I’d go for the 37/32 or something on the yokos based on what I’ve seen for the re71s in prior pages of this thread. Not sure there are really any minor mods you can do besides driver ones. The next place to go is camber plates and going 17x8 square Last edited by rhop101; 09-07-2019 at 08:28 PM.. |
Appreciate
0
|
09-27-2019, 02:27 AM | #108 |
Lieutenant
329
Rep 455
Posts |
I learned a lot in my first year of AutoX and made huge improvements over 14 days of racing. My region is usually dominated by a guy who has consistently shown well at Nationals in a prepped 350z that won STU twice with a previous owner. I started off utterly uncompetitive (20% off pace) and finished about 10% behind his pax/rdp adjusted pace.
Next season I'll jump from the novice class (not running for seasonal points) to STX. I'll also be on Apex Arc-8R 17x9et42's with a 5mm spacer up front and RE71-R's in 255/40-17 with a light fender roll...but I could be convinced on Yokohama Advan AO52's instead. I might also Bootmod3 flash the ECU and do a muffler delete for less weight. I'm hoping that all those changes will work with the suspension mods I did earlier this year, as well as continuing to improve with AutoX seat time and iRacing practice, to get me another 5-10% in pace to be competitive. |
Appreciate
0
|
10-13-2019, 12:47 AM | #110 | |
Lieutenant
329
Rep 455
Posts |
Quote:
Edit: After some additional reading I think that's based on the 2017 Catch-all definition for STX ([3.1-5.1L] NA or <2.0L Turbo, 4-seats, non-sportscar). The '17+ 230i wasn't specifically classed at the time I inquired after ordering the car so it makes sense based on the 2017 rules set. The '14-16 228i is classed by name and therefore goes to STU. The '17+ 230i is not otherwise classed by name and therefore falls into the STX catch-all. If they intended the 228/230/235/240 to be inherently similar, they would have used a naming convention similar to the 3-series entries in STX like "3-series (E46 chassis, non-M)". Edit 2: I guess the confusion I'm having is that I don't understand why the 228/230 is in STU (Catch-all: >5.1L NA or [2.5-3.1L] Turbo, 4-seats, non-sportscar). Shouldn't it be in STH (Catch-all: <2.5L Turbo, 4-seats, non-sportscar)? None of this makes any sense to me.
__________________
17x9 APEX Arc8-R, 255/40/17 RE71RS, Vorshlag Plates, Swift Spec-R Springs, m-Performance Bumpstops, Dinan ShockWare, Paragon 2-piece rotors, Carbon lip, custom 3" alumalite splitter, GTS wing, FTP Intake and Charge pipe, BootMod3 Stage 1 OTS
Last edited by 230iZTR; 10-13-2019 at 04:20 AM.. |
|
Appreciate
0
|
Post Reply |
Bookmarks |
|
|