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Jon, Sorry I missed you at LRP, but went to Thompson to crew for my cousin and his son who ran mini stocks for the first time on the road course, 1 st and 3rd, not bad.
I would like to see the mods to the dust shields.
The issue I had was that the rear end became loose under trail braking into the left hander and also under hard cornering.
Here are the specs for my car:
Front Camber: 1.4 degrees, Rear Camber 1.2 degrees, toe out .06 degrees front, toe in rear ,23 degrees
Car was corner balanced:
LF 914.8#, RF 870.2#, LR 559.2#, RR 531.8 # this is .8# from optimium seeting.
Cross weight 1429,3 49.7%, Front 1785.0# 62.1%, Rear 1091.0# 37.9% Total 2875#
Tire pressures at LRP:
First Session:
Cold: LF 32, RF 32, LR 30, RR 30
Hot: LF 41, RF 39, LR 34, RR 35
Second Session:
Cold: LF 31, RF 31, LR 30, RR 30
Hot: LF 40, RF 38, LR 33, RR 33.5
Hopefully this provided some data to make suggestions.
Originally Posted by slinger688
To reduce oversteer
1. You could use a little more front camber, around -2 to -2.2 to start with. Also adjust the rear camber using the thermometer or the chalk method.
2. Also you could lower the rear height a little
3. Increase the rear sway bar stiffness
4. Reduce the front sway bar stiffness
5. Find the best psi for the tire type you have, then make sure your rear tires are running at that psi hot.
There are many more things to do (adjust the spring stiffness, retune the shocks, change the ride height differential, etc) but you can start with these. Do them one at a time and see if you like it.
slinger - Zre has a car that is too loose in the back. If it is an oversteer problem then I believe you should be decrease rear sway bar stiffness and/or increase the front bar stiffness.
Zre - Congrats on the Thompson race. The results must make people happy.
I will get you pictures of the dust shields.
As for the tail end looseness under trail braking. Another question: What brake pads front and rear are you using? You said Poly B for the front, but what do you have in the rear?
And yes I have had to deal with the same issue, but have had it going into T1 as well as T3 (lefty) and I have read magazine articles that have noted this in the R56s they have tested. I also have this problem going into T1 at WGI. I find that tire pressure helps.
Tire pressure - Here is what I run on both my Toyo R888s and Dunlop ZIIs
39 max Hot on any tire. I find they start to lose grip any higher than that.
I run the rears 1 psi lower, hot, than the front, hot. At WGI, I find 39/38 front/rear to be a good balance. The 1 psi lower in the rear seems to really calm down the back end. Yesterday at LRP I found that 37/37 to work well (by accident - I started out at a too low of a cold pressure for the day). With this I found that I could work a bit more throttle steering than my past practice of 39/38 and I worked on brake application to control the back end.
Brake application - I find the rear is very sensitive to how dramatic the initial brake application is. An application that is very late, very quick, hard and then relaxed to setup the trail brake really upsets the back of the car. In mine I found that an earlier, rapid ramp-up in brake pressure and then relax to set up the trail brake works much better. However, I almost looped the car trail braking into T3 yesterday in the rain (last session). The traction control caught it. My thought was I was carrying more speed into the corner than the tires could handle and the trail braking loosened the rear too much.
Brake Pad - I am suspicious of having too much pad in the back. I am running the Wilwood Poly H in front and Carbotech XP8 in the rear. Seems to be a good mix but I would like to try the stock pad in the rear to see if it has a bit less grip and if that reduces the braking tail wiggle. On the other side of the coin, I like that that the rears takes on some of the braking load so I have not tried that one.
Sorry I don't know the suspension settings that I have except the front camber (-1.5 deg). The rest should be stock settings including a bit of toe-in at the front. With that, my car is very neutral and not tail happy at all. The springs and shocks are the MINI Sports suspension option and the sway bars are 27mm solid front and 25mm hollow rear (yes, it corners very flat for a street car).
Almost missed it. Had 3 great session at the start and then had the track almost to myself in the wet (rain stopped) for the last session.
Had an instructor with over 100 days on that track and he showed me few things that worked well for me. Had him in the car for 3 sessions and it proved to be very helpful.
My run group was a mix of advance and experienced drivers that were good to run with. And, for some reason this little gray car only allow 3 passes the whole day. No, it wasn't that I wasn't doing pass-bys; either it's getting to be a quick little devil or everyone else is getting slower...
I have been running the EBC yellow pads in rear at track days and the Red for street. THe D2 coiiovers have Swift springs 392# front 448# rear as recommended by the Swift techs.
Also run stock bar up front and H-sport 25.5 mm rear. I had the seeting on the center so I can soften up a bit.
Sounds like to had fun at LRP. We should meet up midway between to discuss personally our cars.
Zre - I wasn't a fan of the yellow stuff pads when I used them (tried them on the front). They would gain friction as they heated up during braking and it was difficult to modulate them. I ran 2 sessons on them at NJMP Lightening track and switched them for a set of Carbotech XP10s. Oooooh, they are so much better. Some people like them, but I would think that this would not be good in the rear while trail braking where you are trying to release grip as you enter the turn but the pads are gaining grip. Here I would try the Red stuff or even go to the stock MINI rear pad.
As for suspension, you have a lot of oversteer dialed into the suspension with the RSB. I am not sure what the spring combination is doing for you. But people with racing experience tend to like this setup. If you keep your foot on the gas in corners it should be good and it will provide you with opportunity for a good bit of throttle steering. Of course, this is all dependent on what the shocks are doing for you. Too many variables to really say what to do here... except that going to a softer setting on the RSB would be an easy and safe try.
I have also run into an issue with abruptness in the release of the brakes while trail braking and the back end wanting to come around. I didn't understand it as I figure that I would be adding weight to the rear and it would have more traction, not less. But the way it was explained to me was that because I was turning and braking at the same time, releasing the brakes abruptly add steering traction to the front which caused the rear to twitch out. My point here is that the car really responds well to smoothness. This is tough to do at LRP going into T3 especially if you are accelerating hard out of T2 and trying to not loose too much going into T3 and trying to get the braking done in a short distance. There is a strong desire to brake late, hard and release at the last moment. This is all the things that upset the car. I brake a little earlier, lighter and longer and can carry the turn nicely (so I am told by my last instructor).
Also, while I don't use it as much as I should, as FastTruck said, if you don't have a datalogger you should get one This will help you to understand if changes you make are helping or hurting you. With all of the variables that you have to changes settings, this might be the only way to sort changes out as either good, bad or neither...
Hmmmm, meet up half way? It is possible, but Fiddlehead Brewing is a little too far for me Need something closer to Albany...When's your next trip to LRP?
Softer spring rates in the front reduces understeer. Softer sping rates in the rear reduces oversteer. Suspension tuning is not a one size fits all deal. It really depends on how you drive and the track. And it takes a lot of trial and error to tune.
I am also not a fan of ebc yellows. Give me the modulation control from carbotechs anytime.
I can meet you halfway to discuss cars, but that would be LA or SFO.
I do have a data logger TrackAddict. I use it a LRP but the changing weather conditions may it difficult to compare sessions. I will get some carbotechs for season at LRP.
Going to be out of the country early October so I am not sure on any more track days. Albany is not bad wee have to see. Are you going to LRP again this year?
LA or SFO tough choice. Thanks for all the advise, gives me something to work on.
Zre,
I am not a MINI expert but would bet (as Slinger correctly said) your rear spring rate is too high. If your car over steers on turn in, address it by lowering your rear spring rate. A fine tune is to adjust tire pressures because that adjusts the tire spring rate.
Setting up a car is a difficult process and about impossible without using data. It is easy to loose your way in all the complexities.
Start with the basics - controlling the contact patch and spring rate of the tire.
Look at the balance front vs rear, acts the same turning left vs right, coasting vs throttle on, etc.
The guys here have given you a lot of very good advice already.
Think softer springs for more grip on race tracks.
Going to be out of the country early October so I am not sure on any more track days. Albany is not bad wee have to see. Are you going to LRP again this year?
LA or SFO tough choice. Thanks for all the advise, gives me something to work on.
Zre - I've got to learn to read the fine print. I read your location, Burlington, and thought VT not Ct...my bad So there lies the confusion.
Albany would be a hike for you and nothing for me. Some of us are looking at maybe meeting at LRP on 10/31 to watch Veggivet run around the track. I'm done for this track season but could go to watch, especially if Slinger is there.
Alot of people get confused with address. Have a wedding at Interlaken on the 31st. Albany is not a terrible ride. Used to be Chief Tech for Mo-Hud Region SCCA. How about Great Barrington, MA?
Alot of people get confused with address. Have a wedding at Interlaken on the 31st. Albany is not a terrible ride. Used to be Chief Tech for Mo-Hud Region SCCA. How about Great Barrington, MA?
zre — I think I saw you at LRP on the 10th but I was on the way out. Were you parked in the front row near the tower? I looked for you earlier, when I came down after the control clinic to eat lunch, but didn't see a white MINI. I would have stopped on the way out to say hello but we needed to get home by a certain time. There were a lot of MINIs there! Two R53 GPs and a new F56 JCW which Ian said was being tested by the press. Plus you and at least one other. Hopefully I'll meet you soon.
Yes that was me near the tower. Had a good chase/catch with one of the GPs in the second session, hope to meet up with him at Palmer next year. We are trying to get a group together in Great Barrington, hope you could make it.
Maybe next weekend to meet up. Part of Mo-Hud late 80's early 90's.
Originally Posted by zre
Yes that was me near the tower. Had a good chase/catch with one of the GPs in the second session, hope to meet up with him at Palmer next year. We are trying to get a group together in Great Barrington, hope you could make it.
This may be a little bit like herding cats but give it a try for Saturday? Lunch? Microbrew anyone"
Lunch would work. There is a place just north of town center Barrington Brewery & Restaurant, opens at 11:30 Saturdays. 420 Stockbridge Road just after Butternut on Route 7
Hey, has any one run Ethanol-free gas on the track? I may give it a shot.
I tried some Stewart's Shop 91 octane ethanol free gas on a trip to Cape Cod and I swear that it ran better, felt better and sounded better. Plus I got 2 mpg better mileage with it over the 10% ethanol 93 octane gas I filled up with when I emptied the tank.
09-13-2015, 07:25 PM
Need something closer to Albany...When's your next trip to LRP?
So there lies the confusion.
