I am racing in GS street tire class and doing vary well. However, I still feel I could improve about 2 seconds on a 60 second course. One of my problems is getting my car to rotate. I am doing left foot braking and trail braking into the corners and this works quite well but I feel I am using this as too much of a crutch and am loosing time. I am using Kumho MX tires with about 49psi/F and 45psi/R. Any ideas would be greatly appreciated.
Thanks :???:

 

How did you arrive at such high pressures. I run the MX's at ~36-38lbs. I know they feel better at higher pressure, but they might work better at lower pressures. I've had a pyrometer on mine and 38lbs is pretty good, other than the outside edge heating up because there's not enough camber.

 

I marked the outside edges with white shoe polish and started with 38/42. At those low pressures the tires were rolling over the edges. The wear marks on the outside of the tires started disappearing until I went up in pressure. I might try to go lower if it works for you. Thanks :???:

 

Have you messed with the front or rear alignment yet???? do a search on the forum for more info!!!

 

Ok, dont mean to horn in to this discussion as a newbe, but I have a question.

I have heard the tearm "Lifting" in reference to going into a turn or in a turn or
comming out of a turn? what does that mean?

I am also getting a rear sway bar from Randy, how will this help my handling?
what will I feel, how should I enter the turn, go thru it, and come out of it? and
what should I notice/feel with the sway bar that I feel with the stock one?

thanks everyone/anyone. sorry for the breakin.... :smile:

 

"Lifting" means lifting off the throttle. With the clutch engaged, the engine braking transfers weight from the rear to the front and the car turns in or rotates better. Usually done when entering a fast corner where braking isn't necessary, but a little sharper initiation is needed. Mid-corner it is used as a corrective measure to tighten up the line, but be careful and ready to modulate the throttle and get back in it if the car starts coming around too much.

How the heck are you guys left foot braking on this car? I can hardly hit the tiny brake pedal with my right foot much less my left. Everytime I try and left foot, I miss the brake or I catch both the brake and the clutch. New pedals maybe?

 

The term lift refers to a rather abrupt lifting off the throttle... it is done to adjust the attitude of the car or more specificly induce oversteer... at times I lift and tap the brakes for a more pronounced effect....

The bigger rear sway bar will help change the balance of the car away from understeer (the car wanting to go straight) at the limit... meaning that you should not need as big a lift to get the car to rotate as well as the car taking a more neutral line on things like mountain runs (where you should not be at the limits of the car or yourself) neutral meaning a car that is not under or over steering...

Hope that helps ... the only cheap, safe place to explore how the mini handles at the true limits is to run some auto-X events....


>>Ok, dont mean to horn in to this discussion as a newbe, but I have a question.
>>
>>I have heard the tearm "Lifting" in reference to going into a turn or in a turn or
>>comming out of a turn? what does that mean?
>>
>>I am also getting a rear sway bar from Randy, how will this help my handling?
>>what will I feel, how should I enter the turn, go thru it, and come out of it? and
>>what should I notice/feel with the sway bar that I feel with the stock one?
>>
>>thanks everyone/anyone. sorry for the breakin.... :smile:

 

>>How the heck are you guys left foot braking on this car? I can hardly hit the tiny brake pedal with my right foot much less my left. Everytime I try and left foot, I miss the brake or I catch both the brake and the clutch. New pedals maybe?



I don't left foot brake... so it is not a problem for me...LOL.... I feel that LFBraking takes away too much momentum.... I have played with it on the street in the MINI and might play with it again early in the season next year... and yes the pedal is dam small....

 

>>
>>>>How the heck are you guys left foot braking on this car? I can hardly hit the tiny brake pedal with my right foot much less my left. Everytime I try and left foot, I miss the brake or I catch both the brake and the clutch. New pedals maybe?
>>
>>
>>
>>I don't left foot brake... so it is not a problem for me...LOL.... I feel that LFBraking takes away too much momentum.... I have played with it on the street in the MINI and might play with it again early in the season next year... and yes the pedal is dam small....
>>


I use old wrestling shoes that were left in our coaches office at the end of the school year and were going to be thrown away. They work great. Several drivers in the Reno area use these as a cheap driving shoe. Just got the results from this weekend. First on both Sat. and Sun. and tied for first in the points. I still need those 2 seconds. Come on, any help on rotation?

 

I use Puma Mostros (basically a modified low top race boot) and my feet aren't big by any means but I still can't hit that thing consistently with my left foot.

As for tips to encourage rotation, try tire pressure and front/rear toe. In terms of driving technique, I found myself abusing the ABS a little last time. I would brake a little later than usual and hold the braking into the turn-in point so that I'm actually trail-braking upon entry. This helps me point the car a little better and then power out. The car is going to push on power anyways and there's nothing you can do about that so I just pitch it a little earlier and let it push/slide out on exit.

 

I went to this driving school. I went from being in the middle of the pack to setting FTD's at events. Best money I ever spent. You will get more seat time than you ever dreamed of. You will be instructed by National Champs. They will drive your car with you in it at 80% its ability and show you it can do things you never thought it can.

Evolution Driving School

 

OK, this will bend a few minds - I thought it was nuts until I tried it. Try 38 - 40 PSI in the front and 55-65 psi in the rear! That's right, 55-65. My best results were at 60 psi but your rotation may vary.

I got this from a fellow competitor running a FWD ford thingy in GS (I'm running a MCS) who came out of nowhere, based upon past performance, and put a serious whuppin' on everybody in the class. In talking to him after finishing our runs, he was amazed too. I asked him if he did anythig different that day and he told me about the pressure. He said it was the first time the car had really rotated and that he was now able to throttle steer.

We were both running Khumo Ecsta V700's and I said that the max pressure advertised on the sidewall was 40. I said I was even a bit nervous about going to the 48 PSI recommendation I got from Brian Garfield (last year's national pro solo champ driving an MCS). He said he got the information from a friend that was crew chief for a pretty successful road racing team and that they run 65 PSI (and more) - that the sidewall rating is for load bearing - and they've not had a problem due to the high pressures.

With some trepidation, I tried it at my last autox and was flabbergasted! I went into the first turn after a slalom but not fast enough speed to brake and lifted a little just as I started to turn and encountered very mild oversteer. Wow! Rolled in a touch of gas and was in a neutral attitude (the car, not me - I was grinning from ear to ear and totally stoked). It's the opposite dynamic compared to a rwd car and very counter intuitive. Lift and the back end goes out, add a little throttle to nuetralize it or even more throttle get that old familiar understeer. I was lucky I wan't too hot going entering the turn or it might have been more oversteer than I could have responded to for the first time.

The rest of the day was playing with throttle, counter steering and drift control (well, sometimes it was controlled). It sure was fun but it's going to take a while before I'm more comfortable.

For those who've been discussing alignment - I had my dealer try to give me max negative camber front and rear, max toe out in the rear and max spec toe out up front. Judging from the before and after printouts, MINIs are very resistant to adjustment - not much at all.

That's been my experience -

<now donning flame retardant gear for flames from the judgemental or doubtful >

 

Pablo

At 65 psi, the rear tires should be crowning pretty heavily, and have lower contact patch
than the fronts, essentially you are now running much thinner tires in the rear than front.
This is why the car feels more neutral to you.

Did you try the same course with the more normal pressures vs this set and how were the times like?

I run Ecsta V700s on road racing in my 89 M3 club racer, and I set the colds at 29/28 front/rear
and at the end of a 30 minute sprint race at Laguna last weekend, they were close to 36-38 psi.

According to Kumho, they recommend 36-38 psi hot pressures.

Bora

>>OK, this will bend a few minds - I thought it was nuts until I tried it. Try 38 - 40 PSI in the front and 55-65 psi in the rear! That's right, 55-65. My best results were at 60 psi but your rotation may vary.
>>
>>I got this from a fellow competitor running a FWD ford thingy in GS (I'm running a MCS) who came out of nowhere, based upon past performance, and put a serious whuppin' on everybody in the class. In talking to him after finishing our runs, he was amazed too. I asked him if he did anythig different that day and he told me about the pressure. He said it was the first time the car had really rotated and that he was now able to throttle steer.
>>
>>We were both running Khumo Ecsta V700's and I said that the max pressure advertised on the sidewall was 40. I said I was even a bit nervous about going to the 48 PSI recommendation I got from Brian Garfield (last year's national pro solo champ driving an MCS). He said he got the information from a friend that was crew chief for a pretty successful road racing team and that they run 65 PSI (and more) - that the sidewall rating is for load bearing - and they've not had a problem due to the high pressures.
>>
>>With some trepidation, I tried it at my last autox and was flabbergasted! I went into the first turn after a slalom but not fast enough speed to brake and lifted a little just as I started to turn and encountered very mild oversteer. Wow! Rolled in a touch of gas and was in a neutral attitude (the car, not me - I was grinning from ear to ear and totally stoked). It's the opposite dynamic compared to a rwd car and very counter intuitive. Lift and the back end goes out, add a little throttle to nuetralize it or even more throttle get that old familiar understeer. I was lucky I wan't too hot going entering the turn or it might have been more oversteer than I could have responded to for the first time.
>>
>>The rest of the day was playing with throttle, counter steering and drift control (well, sometimes it was controlled). It sure was fun but it's going to take a while before I'm more comfortable.
>>
>>For those who've been discussing alignment - I had my dealer try to give me max negative camber front and rear, max toe out in the rear and max spec toe out up front. Judging from the before and after printouts, MINIs are very resistant to adjustment - not much at all.
>>
>>That's been my experience -
>>
>><now donning flame retardant gear for flames from the judgemental or doubtful >

 

Bora,

In addition to the smaller contact patch, the higher pressure also has the effect of increasing the spring rates. Until I bumped the pressure to 60 PSI, I always had understeer.

The autox's we have in my area are usually sold out, so it's rare to get more than 4 runs with measured times. Each run is somewhere between 50 to 70+ seconds with at least 20 turns. I consider the first run to be orientation and not even close to 10/10ths. I figure I have 10-15 minutes between each run. At my stage of development (1st year) consistency is just a concept - from 1st run to last I usually get 3 - 6 seconds faster though lately the variance is starting to narrow. Also, every autox event brings a new course so time comparisons are not valid.

My main comparison points are against the front runners - I'm narrowing the gap each event. After 6 events, I'm finishing in the top 3 of the novices and I'm currently 6th out of 33 in the season points standing for my class having missed two events.

I've tried some of the things that Truckee mentioned - left foot braking, trail braking and even the hand brake a few times. Nothing seemed to loosen the rear any until I kicked the rear pressure up way more than a notch.

In about 3 weeks, I going back to Level 2 Autox school so I can play some more - I should get about 20 runs over the same course and it will be timed so I should have a better feel for pressure effects then.

Though I have nothing to compare against road courses, I think there's a big difference between a road course and and autox. Things like seat time and turn density are biggies - that and the road course layout doesn't change from one weekend to the next. I was interested in hearing your tire pressure increas after 30 minutes driving time. At my first L-2 school, I didn't check my tire pressures until after the 7th run (we had about 3 minutes between runs) and was stunned to find the fronts had increased over 15 psi!

In GS with an MCS, there's few changes you can make to alignment that have any effect. I spent $150 to have the MINI shop try to set the car with more toe-out frant and rear and to give me the maximum negative camber the could give me. The before and after printout comparison was, er, illuminating. No camber change at all. Right front toe went from 0.05 degrees to 0.13 to match the left front and sit at max specified range. The rear toe was off between the left and right and that was corrected but total toe for both did not change in the end. The car turned in a little more sharply but I still had a fair amount of understeer. I didn't get noticeable rotation until I pumped the rears up to 60.

Like I said, your rotation may vary.....


>>Pablo
>>
>>At 65 psi, the rear tires should be crowning pretty heavily, and have lower contact patch
>>than the fronts, essentially you are now running much thinner tires in the rear than front.
>>This is why the car feels more neutral to you.
>>
>>Did you try the same course with the more normal pressures vs this set and how were the times like?
>>
>>I run Ecsta V700s on road racing in my 89 M3 club racer, and I set the colds at 29/28 front/rear
>>and at the end of a 30 minute sprint race at Laguna last weekend, they were close to 36-38 psi.
>>
>>According to Kumho, they recommend 36-38 psi hot pressures.
>>
>>Bora

 

65 psi in the rear, this appears to be a Band-Aid solution. With this high pressure you will be crowning the tire excessively and heating the inside up too much. The only way to tell is to test the temperatures. To set-up your car you need to start at the front and set your pressures for roll over and temperature. I run 46 to 50 psi in the front on Kumho V70A (exsta's) 205/45/16 on MCS rims on my cooper with SS+. the cooper S may need a bit more because of the weight increase. This pressure depends on surface. Higher for concrete and hot days.

For the rear you then need to tune off the front, I have driven some cars where the rear rotates too much and I have run higher pressures in the rear to tune that out, the 2003 Civic Si needs this set-up. For the mini you need to run less pressure in the rear than the front. I have spoken to the Kumho engineer at an event in Vancouver put on by the VCMC and his recommendation is to add pressure to the end of the car that is loose. The mini is anything but loose on the rear so he recommended, along with others I have spoken to and discussed this with over the years, to take pressure out of the rear to get it to rotate. I run 5-6 PSI less in the back at the moment and have only added toe out to the front. The car rotates fine and is predicable even on the first run when the tires are still cold.

65 psi might work but if you run allot of events you are going to wear out your tires early and your times will be slower.

You don't have to take my advise but it has worked for me and many others. this set-up have taken me to many wins, including Canadian National Champion in H stock for 2003.

I hope this helps some out there. A great recourse is grassroots motorsports magazine and their forum. They will answer your questions and are very experienced. You might also try an Autocross web board. Here are some links:

http://www.grmotorsports.com/

http://www.vcmc.ca/ - This board has some of the top Canadian competitors on it and the fastest autocrossers in the world Joe Cheng and Gary Milligan .....A Mod US national champions to numerous times to count

Colin

 

I run 205/40/16 Kumho v700 and I find that 50f/48r works best. To me if I run as much as 2psi more in the rear, the car gets too much oversteer and I'm all over the place. running 2 lbs less in the rear feels best for me and i can still get a littls bit of oversteer in the tight corners. This setup has been giving me consistent !st place finishes as well as top ten PAX times.

I was running 44f/42r, but after goin through a pair of front tires after 6 events, I was told by a MC driver who had his tires much longer than I, that running a higher pressure will help them wear evenly and last longer.

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