I guess what I am trying to ask is not "where will my toe out end up", what I want to know what is the magic number in inches or degrees at which we got from "this is great for HPDE" to "this is no longer good". Basically I don't want to just slam it on max camber at the track and hope my toe out is close enough, I'd rather have the alignment shop mark up my plates for my desired max camber setting with acceptable toe out spec.
The only real way to know the proper track camber setting is to use a tire pyrometer. Camber and Pressures are right when you have the same temps on the outside, middle and inside of the tire. This ensures you are using the whole tire in the corners. Rule of thumb is about -3* of front camber to start. This is also HIGHLY dependent on the sidewall stiffness of the tires.
I think toe changes about 1/16" a side per degree of camber change. 1/16 - 1/8" total front toe at -1* or so of street camber (IIRC). You can probably measure this with the car on stands and some simple reference points like strings.
- Ian
2000 M Coupe, stripped and DE prepped
46mm wheel bearing socket for rent - $30 deposit + $10 fee. PM for details.
Here's the way to align a dual-use BMW E36 or E46 with Vorshlag camber+caster plates and coilover shocks (for track+street or autox+street):
- Go to the alignment shop with the ride heights set and at MINIMUM front camber adjustment (for the street). Camber should correspond to the farthest outboard camber mark on the plates - the minimum setting.
- Set your caster at the maximum positive setting. Luckily, we always ship the plates this way - on an E46 or E36 you have to unbolt the main plates from the bearing holders if you want to change caster (almost nobody ever does).
- Ask the race car friendly alignment shop to check the total toe-in at the front. It should be around zero or even 1/8" toe in (more on that in a second - no need to set this yet)
- Align the rear to your tastes. We usually set it at around -2 to -2.5°, but we are still experimenting with more because at full cornering load the rear seems to still go positive (see pics below).
- Set the rear toe out to -1/8" or even -1.4" total toe in. We have tested with favorably with 1/4" total toe in out back and its faster on track and in autocross conditions. Power application on corner exit is better.
- After they have your street settings checked have them raise the front end, loosen the camber plates, and slide it all the way in. Tighten and re-check.
- That is your max camber setting. Its usually around -4 to -4.5° camber at lowered ride heights with coilovers. This may be perfect for your car, especially for lower speed autocross type events. Or you may want a bit less - most users seem happiest on track with -3 to -3.5° camber. The more grip you make the more camber you lose cornering, and the more static negative camber you need. (with 275mm R compound Hoosiers we run -5° for autocross and -4° on track; less grip means less static camber needed)
- Once you have picked your camber setting (again, -3.5° is a good bet) have the shop set it to that and mark the pointer and associated engraved mark on the plates with a sharpie, or count the marks and make a note of it in your log book (you DO keep a log book for your various settings and event results, right?)
- The toe change over this camber swing is usually about 1/4", when going from min to max camber. KEEP THIS IN MIND BECAUSE TOE IS WHAT WEARS TIRES THE MOST. For autocross we tend to run 1/4" toe out at max camber settings for the best turn in and grip. This tends to swing the toe to about zero for street use. For road course using 1/4" toe out is "a bit darty" for most folks and will impact tire wear. 1/8" to 3/16" total toe out is more reasonable and still has knife edge turn-in.
- Have the shop now set the toe at your max camber setting to suit your needs (autocross or track; see above) and lock it down. Then have them slide the camber back to you minimum street camber setting and note the toe. It should be around zero toe for the street, or as much as 1/8" toe in.
- Having some toe-in for your street setting is fine, and in fact makes the car more stable and tramline less over ripples and crowns in the road. Zero toe is optimal for wear but as much as 1/8" toe in or toe out has minimal affect on tire wear. Drive around with more than 1/8" on the street and you will notice more tire wear. All that hubbub about offsetting the crown in the road with different camber from side to side is an old wives's tale.
- If the shop refers to toe in degrees ask them to switch the settings on their machine to total toe in inches - this is what racers refer to because most of us buy our own toe measuring palates ($50, Longacre) and check it periodically.
- To optimize your camber for track or autocross buy a probe type pyrometer (no, infrared doesn't work - you need to probe under the surface of the tread) and use it during testing. Skidpad the car (150 to 200' diameter) for autocross use and hot lap testing for road course. That deserves its own thread, and in fact has been discussed in the track forum at length I'm sure.
That's all you need to know. Easy as pie. Setting the camber track side takes about 45 seconds per side - raise the front corner of the car (yes, RAISE THE CAR; I've seen goofballs adjust to max camber with the car on the ground and it SLAMS the strut into the strut tower opening and damages it), loosen the three strut top nuts with a 13mm deep socket, slide the wheel in or out to your camber mark, tighten the nuts back to 16 ft lbs (just a hair over hand tight), and lower. While you have the car in the air you can also check shock settings, change tires, inspect the pads, check the front swaybar setting, etc.
If you know the toe at both the min and max setting there's little reason to check it, but many racers do have a set of toe plates and still verify it periodically. A once-a-year shop alignment is still smart money, as things can shift or slide in the rear, especially if you tend to run into curbs.
Note the front and rear camber under load. Rear could use more static negative camber, and that was with -2° out back and only RE01R "street" tires on asphalt
Left: The front has -4.2° static camber. Right: Same car same day under max cornering load (1.2g). Note the nearly zero front camber and positive rear camber under load. This is on Yokohama AD07 street tires and concrete.
Last edited by Fair; 06-03-2008 at 10:16 AM.
Terry Fair @ Vorshlag Motorsports
With the camber plates at full castor, I can only get -3.2 degrees maximum. Is that right?
'95 318i - DASC Supercharged - 269° Camshafts - 30lb injectors - Ostrich 2.0 tuning - Coil On Plug conversion - 11lb flywheel 228mm clutch - AST 4100's,
I think He said negative toe out (-1/8"), which is really just toe in.
- Bret
I agree, altho you're gonna cook tires a lot quicker if it's a daily. If you're having power application problems that can't be tuned about by dialing back the rear sway bar, rear toe in is a great way to do it.
Originally Posted by dallasfan824
My experience is very much the same as what Terry has relayed.
TC535i, I don't think the rear sways will help once you're out much over 200-210 RWHP. The problem comes from power application moving the rear wheels to toe-out. The rear sway bar will definitely help with rear camber, as will stiffer rear springs. People need to remember though to just go as stiff as needed on spring rates, anything more and you also lose traction.
Neil, I'd suggest 1/8" rear toe-in (total) as a starting point for any from stock to 220 RWHP. If you've got much more than stock and are finding the back-end too tail-happy on corner exit, but fine everywhere else, than try moving closer to 1/4" rear toe-in (total). If your over 230 RWHP than 3/8" might even be good. I like it anyway.
Although I'm not able to get as much negative camber as I'd like (Terry, I've been extremely busy but we'll need to talk and "put our heads together" to see if there's something further that can be done). Like Danny318, I'm not getting all the front camber I'm after. Only getting -3.5° front camber all the way in. That's OK, but I'd really prefer about -4.0° with my 265/35/18s (BFGoodrich g-Force R1), although the pyrometer is so far saying we're close to where we should be, there is more to be had.
I approached things only slightly different in that my initial alignment settings were my track setup (then my street setup - if I'm going to compromise the street is where I'll do it):
First - I do my alignment setting with me in the driver's seat as the E36/E46 suspension geometry is such that you loose camber on compression and me being at 200 lbs, even with 550lb front springs, the car looses approximately 0.2° front left camber when I'm there versus when the car is empty. To compensate for this and not have to run different positions left to right, I shim my left front strut (at the hub mounting - only a little if using OE length bolts) to match the right with me in the car and the plates set to the same position. No need to get overly fussy, just close, as all these setting change slightly once you drive/run the car.
- Track
- Camber
- Front: -3.5° (this is with the camber plates moved in to max travel. At the moment, my car gives slightly less camber than the -4.0° I'm looking for)
- Rear: - 2.5°
- Toe
- Front: 0" (will be switching to 1/8" out)
- Rear: 3/8" toe-in
- Caster: maximum. Don't recall the figure but think it's around 6.5° (had to reduce it slightly to maximize front camber)
---------------------------------------------------------------
- Street
- Camber
- Front: -1.95° (second mark in on driver's camber plate for my car. We then set the passenger's side to match and scribed & sharpied it)
- Rear: - 2.5° (untouched from track setup)
- Toe
- Front: 1/4" toe-in (the switch to 1/8" toe-out for my track setting will adjust this to a tire friendlier 1/8" toe-in)
- Rear: 3/8" toe in (untouched from track setup)
This setup woks well for me running RD sways full stiff front and 3/4 soft rear, springs 550lbs-F and 650lbs-R, bushings, etc., etc.
I run the 3/8" toe-in on the rear to keep the tail-end planted on corner exit. Currently have a problem with my piston rings not seating so we've not been able to tune the engine, but even with that, I expect we're around 240RWHP so that's why the 3/8". The 265's are still breaking loose around 4,000 rpm in second gear in a straight line on most courses, so I figure we're in that range. (New pistons and rings during our 3 week break in July will fix the ring seating and tuning will bring more power)
BTW Terry, we are now 3 for 3 in class wins (B/SP) with 2 FTDs for 2008. Running the AST 4100, Mason Bar, Vorshlag motor mounts, etc.
Just did a Regional on Sunday. Number 3 of the three, and missed FTD to a full race C-Mod Porsche 914-6 on a choppy course that was nice but lacked flow and had several very constricted sections that allowed a C/SP Miata to get within 0.174 seconds and a C/SS Miata to get within 0.860 seconds of our time. We've got a real problem locally with people, mistakingly thinking they can build the PAX factor into the course design Doesn't work as it misrepresents not only run times but destroys car classification.
That's my rant on Go-Kart course design.
Regards, Alan
2008 Canadian National AutoSlalom Champion - BSP
2009 Canadian National SoloSprint Champion - SGT2
(the car and my co-driver, not me)
95 M3 3.2L OBDI (M-Perfect ) http://www.cardomain.com/ride/2078238
was 3.0L (236 RWHP) now 3.2L, well modded - Arrest Me Red
--------------------------------------------
Sponsors: Amsoil, BFGoodrich, BimmerSpecialist.com, Corbeau, Dr. Vanos, StopTech VAC Motorsports, Vorshlag/AST, Zeckhausen Racing, 3M-TrimLine
When only the best will do!
-----------------------------------------
nice
'95 318i - DASC Supercharged - 269° Camshafts - 30lb injectors - Ostrich 2.0 tuning - Coil On Plug conversion - 11lb flywheel 228mm clutch - AST 4100's,
Wow Alan, 2 FTDs in a BSP M3! Nice work. It has been two years since that has happened in my neck of the woods. Can I see some pics?
I know what you mean about the PAX courses, we had one course that was first gear the whole way and so tight most people would have been faster running through it
Thanks for the info Terry.
Originally Posted by dallasfan824
Yeah, but isn't Canadian autocross limited to what fits in a Tim Horton's parking lot?
Seriously, I'm realizing the repeatability challenges of my less than flat driveway, borrowed Longacre bubble gauge, and Craigslist turn plates. I'm taking the car to RRT next Tuesday for alignment and cornerweighting, and my datum will be -3.25 camber zero toe, so autocross becomes all the way in with whatever toe out that gains, and marks at -2 with whatever toe in that gains. Street-track-autocross.
Last edited by motomoron; 06-03-2008 at 03:37 PM.
Old, slow, and in the way.
Terry and Alan, great posts! Thanks. I'll be doing a string alignment on friday, that's some good advice.
Thanks for all the camber related posts, this will definitely help a lot of people. BTW, as a data point with front adjuster at max I am able to get over 13.25" up front on 160mm springs.
Hmm... if the strut top nut is touching the inner edge of the strut tower opening at that caster setting then that's all there is to get... There may be some strut tower issues with your non-M chassis that is limiting ultimate camber, but more times than not it has do with ride height. The lower you car sits the more camber it will get at all plate settings. Of course don't over-lower your car just to fulfill your quest for camber - there's caster available to trade for more camber.
We tend to run our E36 M3 fairly high (13" in front) and still manage -4.2° camber up front at max caster. If your car is sitting higher than that (see example above) you will of course get less ultimate camber. Our Alpha E36 LS1 car sits lower with shortened 4300s and can get -5° camber at max positive caster.
Of course if you have an autocross only car and you want more camber than what you have, move the caster setting to the middle location and you'll gain about a degree more camber travel. This allows the strut to follow the circular opening of the strut tower more closely and unleashes more inboard travel. And for autocross cars, the added camber could be worth the loss in caster if the pyrometer is showing you numbers the point to a need for more camber. Again, at a more normal ride height of 13" this shouldn't be an issue on an M3 - you can usually get more camber than you need at max caster. Its just the non-M cars or the donks that might have to trade a degree of caster for more camber travel.
Alan - this is probably the case for your set-up as well.
Cheers,
Last edited by Fair; 06-04-2008 at 09:55 AM.
Terry Fair @ Vorshlag Motorsports
I'd like to take credit for the wins, but it's actually my co-driver Brian, who's the better driver (much better ). I'm running about 4th-6th spot for FTD so far this year, because I'm currently blind in one eye (awaiting another corena transplant) and therefore also have no depth perception. Talk about a sea of cones and getting lost on track.
I'll put some pics at the bottom. There are a few things that help us here. First, Brian is one of the very best drivers in the region (certainly top 3 and if not the best, than very, very close to it). Second, the car is well prepared, we still have several areas that could be improved if the money were there, but we all know that song. It's one of 3-4 (out of a typical field of 20-40) that have had a good amount of development. Brian's driving ability is such that IIRC every competitor's car he has run during our "Fun Runs" after the competitions, he has beaten their best time on his 1st run!
This is a real "pet peeve" with me. I really don't think most people properly understand how a constricted, tight course completely destroys not only PAX but also the entire vehicle class systems as well. I too have run 1st gear courses and am amazed that people don't recognize that they've completely missed Course Design 101.
Absolutely agree.
Looks like you had a picture in your post that didn't come through. We definitely have plenty of Tim Hortons around but can't use their lots. Locally, we've been renting airfields, a road race course and a stock car oval. This Saturday's club race was on an airfield and Sunday's Regional was in a very large coliseum lot. Unfortunately, in both cases, the course design had several tight constricted areas with a noticeable lack of flow that resulted in choppy runs far better suited to small, lightweight, short-wheelbase than anything else.
Terry, I think it's part of it, at the very least. But, there are some difficult compromise on setup for some of our I'll try to find some time later this week to connect with you.
We've been so pressed for time (absolutely, positively no brownie points left with our spouses ), that we've not been able to work through ride height affects yet. Still need to do some more fender rolling to get the 265's to stop rubbing.
Both Brian and I are supposed to be instructing at this weekend's BMW Advanced Driving School but he's backed out due to the need for some family time and I'm still not sure if I'll make it. Sure would be nice to be retired and independently wealthy, wouldn't it.
Here we're only running -2.5° front camber as running on a banked oval needs much less camber to get proper tire contact for the overall course.
This is leading into the "Stop Box" on the front straight of the oval. You get a good view in the background of the banking that we're running.
This is the car last year with 245's, and softer springs. With the 245's we were able to run lower ride-height, than we are currently. Hopefully, once we have the time to work out settings on a lower ride-height that won't rub excessively, we'll get the camber we're looking for, reduced roll-center, etc.
I know you know the actual answer to that one Neil, he'd receive an O/C (Off-Course) and no time, but I do like the way you're thinking.
Regards, Alan
2008 Canadian National AutoSlalom Champion - BSP
2009 Canadian National SoloSprint Champion - SGT2
(the car and my co-driver, not me)
95 M3 3.2L OBDI (M-Perfect ) http://www.cardomain.com/ride/2078238
was 3.0L (236 RWHP) now 3.2L, well modded - Arrest Me Red
--------------------------------------------
Sponsors: Amsoil, BFGoodrich, BimmerSpecialist.com, Corbeau, Dr. Vanos, StopTech VAC Motorsports, Vorshlag/AST, Zeckhausen Racing, 3M-TrimLine
When only the best will do!
-----------------------------------------
Terry, and friends.
I'm running about 12.6'' hieght up front, with the plates at max castor, which comes out to about 6.5 degrees castor. I have offset control arm bushings too. I had the plates on the middle setting before, but the steering was just too light.
I think that the bolt is not hitting the strut housing, just the plate is all the way over. Not sure why it only wants 3', but 3 is probably just about enough, at least for now. I was thinking maybe if I really really needed more I could shim the front struts the way that people do it, to get a bit more camber.
Last edited by Danny318; 06-04-2008 at 11:56 AM.
'95 318i - DASC Supercharged - 269° Camshafts - 30lb injectors - Ostrich 2.0 tuning - Coil On Plug conversion - 11lb flywheel 228mm clutch - AST 4100's,
+1 to this statement.
We've also played with the 95 M3 offset bushings and it always jacks up everything... alters wheelbase and makes the tires rub at the front wheel opening at full lock, and jacks around with camber and caster. We don't recommend using offset bushings.
Again, if your strut top nut is touching the strut tower opening then that's all the range you can get inboard, at the top. With the circular opening you can trade some pos caster for neg camber, but in non-offset-bushing/non-DUB Nation set-ups you can get plenty of neg camber even at the max pos caster setting...
Alan - your car is sitting way is up in the air. That's why you are seeing limited neg. camber. There's nothing else to rule out unless you also have offset lower bushings. Roll those fenders and lower that beast, or get out the Saws All.
Cheers,
Terry Fair @ Vorshlag Motorsports
I am also hitting the inside edge of the strut tower opening with -2.5 degs camber. So is there any issue running the late M3 LCA's with the non-offset bushing to gain camber and get he wheel centered in the opening?
We only have so much room to use for camber travel before the plates start hitting strut towers so we've kept the minimum camber setting dead square in the middle of the strut tower opening for street set-ups. The large amount of min camber you are seeing is from... you guessed it... ride height.
Yea, at 12.25" ride height that's about where you'll end up for minimum camber (12.25" is somewhat low for the front front). If you raise it your minimum camber will inch closer to -1.5 or -2°. Anything less than -3° will work on the street without excessive tire wear if you dial down the toe properly.
Terry Fair @ Vorshlag Motorsports
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