All V6ers come with the additional underbody strengthening as well.
here has been a spate of screens cracking on the 225 BT coupes due to the body twist.
Definately get your rear camber down. I'd consider trying somewhere in the range of -1 to -1.5 to help with your rotation issues. You have too much rear grip with that much camber.
The tripoding is largely due to no compliance in the rear with the stiff RSB.
Also I bet that you occasionally have snap corner exit issues when the unloaded rear tire comes down if you are back on power. Its never fun when that happens.
I'll have to see if I can find notes on my corner weights from the last tour I was at, but you should easily be able to get down to sub 3100 without too much work. With race seats I had the R down to 3090 before I went the lightweight brake route.
I did not see what your front toe settings were, but I would dial it back to close to zero if you are running much toe out. With -2.5 or more front camber it will reduce steady state scrub and believe it or now help a little with turn in.
Brakes - mushy pedal is a common R complaint. Check the adjustment of the parking brake, and make sure the rear calipers are adjusted correctly. Try ratcheting on the parking brake a number of times, followed by 5 or 6 pumps of the brake pedal. It may help to have the engine running when you do this.
Loss of front grip can be attributed somewhat to the high spring rate combined with stiff sway bar. You can't do both on the R32.
Also check your ride height settings - I'd try for at least 14" center to fender on the front, and 14.25 rear. Too low on the front will compound the weight transfer issue. From the pics you posted it looks like car is possibly too low for the suspension to work effectively.
Last edited by a4tq; 10-25-2011 at 03:14 PM.
- Rear camber is back in line, running about -1.5 and the rotation issues at the last event were much better likely due to that and playing with shock settings. On this course the car would finally rotate nicely going into the center section on both passes.
- I haven't experienced any snap corner exit issues and haven't heard any such feedback from others that have driven the car so far. It is possible that other setup issues have been preventing getting back on the throttle as early as desired and thus, masking this problem...
- Agreed on weight. Seats are the next item on my list.
- Front toe is at 0. I am going to try my GC plates now that I have the correct cups to see if there is more camber using them than the standard KW top mount.
- Brakes... I haven't had a shot to run through your suggestions but I will before this weekends event. What exactly do you mean by ensuring that the rear calipers are adjusted correctly, or was this a corollary to the comment on the e-brake?
- For front grip... I think implementing something similar to max's FSB mod to soften it slightly might help. I guess I understand first hand why you sold yours now.
- I will check ride height as well, I think I'm in the ballpark for what you recommend but I do not have my numbers committed to memory.
Is the season pretty much wrapped for you guys in Texas [ Do I even have to ask about NY... ] ? It might get a little cool here and the risk for rain goes up but it sure it nice to have 2 events a month, every month. Besides, there's only 4.5 or so months until the SD Tour!
They run a winter season in TX, but I generally don't go to those events. My last event for 2011 is this weekend. Two separate events on two days at the same site. All going well I get to test a new UM tune including launch control. Should be fun
Brake comment was related to ebrake and to brake bleeding too. Start by ratcheting the ebrake a number of times to ensure the rear caliper adjusts for pad and rotor wear. The ebrake mechanism will ratchet in the caliper and can sometimes help. Bleeding is a pain. I've had best results by backing the rear of the car on ramps and doing a manual bleed with a helper.
The FSB helps on stock(ish) rates, but not as up up the rates. I think you have well surpassed the rate where such a large bar helps.
Good to hear that the rear camber helped. You can even take it more aggressive and go back to about -1.2 and close to zero toe in the rear. It will get more lively as you take out the rear camber.
Something else to consider is rear rebound settings. Counter to what you may think there a point where reducing rear rebound will help with front end grip, but if you go beyond it, you will start getting push again. If there's too much rear rebound you won't get as effective weight transfer, but its a fine line and very contingent on overall setup, so you'll have to test to see what works for you.
Thanks for pointing me to this thread. It is actually very refreshing to find people who not only got an interesting car, but who also are willing to experiment, learn and most of all share the findings. On top of that, looks like you guys do actually race your cars in actual events, place very well and do not spare time or money to get anything possible that would get you a tenth faster. That's quite rare all together.
I tried to read as much as I could, to understand better what have you been through and how did you arrive to all the conclusions/solutions. It is not an easy read to do at once, so perhaps I will go over it slowly when I get time (something I truly do not have these days).
Just wanted to ask couple of questions, if they have been covered, please point me to post number, no need to retype. In the very first post you are writing about the coilovers you use, the have been revalved. would be very interesting to see how they have been revalved. Do you know exactly what they did (I assume is a shop, you did not revalve them yourself)? Anything that you could tell about would be very interesting. And how was the front bar modified as to have half the rate? I saw a picture in one of the posts, but it is little dark and I just want to make sure I saw it correctly - did you just weld a block (rectangular plate) to the end of the bar and drill a new hole few millimeters further on the block? Or is it something else that I just can't see through the picture well? Thank you.
Glad to see you posting Pyce, you are the pioneer of looking at this platform's suspension geometry and your work on the front's camber curving have saved me tons of time. Great work for anyone looking to make these things handle at the track
The coilovers are H&R RSS Clubsports, they were chosen because they are built around the awesome Bilstein inverted monotubes and came off the shelf with decent spring rates and valving (683/1150 lbs springs as default and nice digressive valving). What I did after they got dynoed is revalve for a more appropriate 700/1300 lbs springs front to rear. Main reason behind the spring bump was the lack of rear wheel rate to reach my target motion ratio with the default springs (with the rear motion ratio of 0.63, 1150lbs springs was not going to cut it).
I had them revalved to my specs (a professional shop did the work). I went for the magic 65% of critical damping at a linear ramp on both rebound and compression curves. The changes were made at the low piston velocity range (0-3 in/ sec) which is the range of dynamic chassis lean. I left the mid to high speed shims stacks alone so I'm not beaten down when driving to and from the track.
The swaybar modification is a bolted and welded rectangular steel extension at each end of the front bar's arm. New holes are simply drilled on the extension pieces to reduce the rate just like an adjustable swaybar would do. The picture is a bit misleading because the distance added (from original hole to new end link mounting point) is almost 2".
When you get a chance take a look at the other thread I linked you to, it's a great read and along the line of what you did back in the days (if only TechEd could also grace us with his presence).
Last edited by The_RoadWarrior; 11-30-2011 at 02:46 AM.
Allow me to just briefly comment on your first line. By far I am not the pioneer at looking at anything. There were others who started this way before. the only thing I did was to put a lot of geometry into CAD and do some simulations, so we get some actual (or close to actual) numbers which otherwise is impossible to get. Reverse-engineering something for the pure sake of understanding how it works is way too far from any sorts of pioneering. At least I see it this way
It is very interesting to read what you have done with the dampers. I would be very interested to see those damping curves. Going linear with 65% critical damping, while leaving the mid and high speed intact - I would love to see that. I would guess they did several dynos, do you happen to have the files?
It is very interesting also to see how did they achieve the linear compression and rebound on a monotube. but most of all it would be critical for your application to see what is the ration rebound vs. compression that you are racing with. That alone can change the entire picture in a curve.
Are you off-season now? Are you planning on pulling the dampers out? There are couple of experiments that we could do and you are one of the most ideal candidates, but of course if you are willing to. We used some interesting, unconventional solutions with the rally car and it actual worked quite well, but is a different car than yours. It would be so nice to experiment little bit with rebound vs. compression on a car like yours, with all the modifications that you have done.
As for the sway bar modification, I need to go find my sway bars somewhere int he garage and measure the full length and see then what a 2" relocation of the hole would give. It would be interesting to calculate more precisely what is the new rate the bar has.
Let me know if you would have time and desire this winter to do some experiments. Thanks.
Ok so I've had my seats in for a bit now and apparently I'm doing it wrong as far as getting the airbag light to clear.
I've got resistors in the plugs on each side - 4.7 Ohm 1/2 watt 5% tolerance - and the airbag code comes right back when cleared. Not my picture, but here's what mine also looks like and I have the two positive wires bridged.
Am I missing something else simple here, or am I just getting a bad connection which is preventing the resistor from closing the circuit? I've checked and rechecked that the resistors are right and haven't found anything else that is supposed to be done. I figure some of you have done this, unless you don't care about the other airbags working.
Just a side note, but I recently discovered that running 2 RadioShack 10 ohm, .5 watt resistors in parallel provides resistance that it close enough to keep the light off. This is handy as these resistors are available for $1.19 per 5 pack at radioshack, so you don't need to order the 4.7 ohm resistors online from a specialty shop. Radioshack also sells all the resistors you'll need if you are deleting seatbelt receptors as well.
I figured that it is probably just not a good connection and that I have to fiddle with it. As simple as this is, my history with messing with the electronics on this car isn't stellar so I figured I'd see what bonehead mistake I might have made. Thanks for the helpful reply!