Return to Roebling Road

m3bs · 09-11-2009, 10:55 AM

I finally got the car back to the track to try out the new suspension. In my previous trip to RR with the car bone stock, I had lots of understeer as expected, but I came away impressed with the overall grip of the RFTs.
http://www.1addicts.com/forums/showp...48&postcount=5

This time I had the Cross coilovers and H&R front bar. I was a bit disappointed with the results, as I was only able to improve my lap time by less than a second to 1:26.0 It was a bit warmer this time, low-mid 80s vs. 78 last time, and the humidity was higher this time. The car felt much more stable with the stiffer springs and damping, but it still understeered heavily which limited my exit speeds from the long, sweeping turns at Roebling Road. I think the improvement would be much greater at a track like Road Atlanta where there are more left/right transitions.

Having also added a JB3, it was time to experiment with different maps. I used map 0 for the earlier runs to make a fair comparison to the previous times. Using map 4, the car defintely pulled harder from trackout to the braking points, and I was routinely seeing 150 on the front straight, a full 15 mph faster than my fully prepped E36 M3 and almost 10 mph over map 0. Unfortunately, this map and all of the others made it very difficult to modulate power through the long turns and especially on corner exit, which reduced my exit speeds. Overall, my lap times were only about 1/2 second faster on map 4 than map 0. Better modulation would improve that significantly, and I plan to consult BMS about what can be done. I could also really feel the rear brakes holding me back on corner exit even with TC/DTC turned completely off, and the rear rotors turned blue.

Finally, I bolted on an old set of 235/40-17 track tires from my M3. What a difference! My lap times dropped by about 2.5 seconds into the 1:23 range, and the car could now be aggressively driven through the long corners. Unfortunately, these were old tires (cord showing on two of them by the end of the day), and not big enough for the 135. After about 3 laps, the front tires were overheated, and understeer again prevailed.

I was still about 2-3 seconds slower than what I can turn in my M3, but I think with some more tweaking, better brake pads and more tire the 135 can get there. My biggest concern is the throttle modulation. This is one reason I gave up on my 944 Turbo years ago as a track car.

The good news is that even running map 4, I never saw over 270 degrees oil temp, and the brakes held up fine, although I was being conservative with them.

Video link:
Sound is terrible, so be ready with the mute button.

rodi · 09-11-2009, 11:33 AM

do you think the understeer could be reversed by a weaker front sway or by adding a rear sway?
were you still on RFTs this trip? (besides trying out your old M3 track tires)

m3bs · 09-11-2009, 11:52 AM

Now that the roll is under control with stiffer springs, going back to the stock front bar might help, although I do like the stable feeling it provides on the street. Beefing up the rear bar might also help, but I'm afraid it would only aggravate the traction control nannies by further unloading the inside wheel.

Yes, same RFTs for the initial runs yesterday, although I did swap sides since the LF took a beating last time.

heyimsam · 10-18-2009, 12:35 PM

I think it is time to start looking into getting the m3 suspension bits! I heard they really help with turning in a more responsive feedback, and I think that could help with the pushing

vitig · 10-19-2009, 07:33 AM

Quote:

Originally Posted by heyimsam

I think it is time to start looking into getting the m3 suspension bits! I heard they really help with turning in a more responsive feedback, and I think that could help with the pushing

Camber plates, m3 bits gains 0.7º and whit camber plates you can 2º.

m3bs · 10-19-2009, 07:37 AM

I'm currently running 2 degrees. I probably won't make any other changes, as I'm contemplating selling the car to fund upgrades to my M3.

09-11-2009, 10:55 AM	#1
m3bs Captain 62 Rep 657 Posts Drives: 95 S54 M3, X5, GT4, GR Corolla Join Date: Feb 2008 Location: North Augusta, SC iTrader: (1)	Return to Roebling Road I finally got the car back to the track to try out the new suspension. In my previous trip to RR with the car bone stock, I had lots of understeer as expected, but I came away impressed with the overall grip of the RFTs. http://www.1addicts.com/forums/showp...48&postcount=5 This time I had the Cross coilovers and H&R front bar. I was a bit disappointed with the results, as I was only able to improve my lap time by less than a second to 1:26.0 It was a bit warmer this time, low-mid 80s vs. 78 last time, and the humidity was higher this time. The car felt much more stable with the stiffer springs and damping, but it still understeered heavily which limited my exit speeds from the long, sweeping turns at Roebling Road. I think the improvement would be much greater at a track like Road Atlanta where there are more left/right transitions. Having also added a JB3, it was time to experiment with different maps. I used map 0 for the earlier runs to make a fair comparison to the previous times. Using map 4, the car defintely pulled harder from trackout to the braking points, and I was routinely seeing 150 on the front straight, a full 15 mph faster than my fully prepped E36 M3 and almost 10 mph over map 0. Unfortunately, this map and all of the others made it very difficult to modulate power through the long turns and especially on corner exit, which reduced my exit speeds. Overall, my lap times were only about 1/2 second faster on map 4 than map 0. Better modulation would improve that significantly, and I plan to consult BMS about what can be done. I could also really feel the rear brakes holding me back on corner exit even with TC/DTC turned completely off, and the rear rotors turned blue. Finally, I bolted on an old set of 235/40-17 track tires from my M3. What a difference! My lap times dropped by about 2.5 seconds into the 1:23 range, and the car could now be aggressively driven through the long corners. Unfortunately, these were old tires (cord showing on two of them by the end of the day), and not big enough for the 135. After about 3 laps, the front tires were overheated, and understeer again prevailed. I was still about 2-3 seconds slower than what I can turn in my M3, but I think with some more tweaking, better brake pads and more tire the 135 can get there. My biggest concern is the throttle modulation. This is one reason I gave up on my 944 Turbo years ago as a track car. The good news is that even running map 4, I never saw over 270 degrees oil temp, and the brakes held up fine, although I was being conservative with them. Video link: Sound is terrible, so be ready with the mute button. Last edited by m3bs; 02-09-2010 at 06:26 PM.. Reason: Added video link
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09-11-2009, 11:33 AM	#2
rodi . . . 183 Rep 2,391 Posts Drives: your FACE! Join Date: Oct 2008 Location: Atlanta proper iTrader: (-1)	do you think the understeer could be reversed by a weaker front sway or by adding a rear sway? were you still on RFTs this trip? (besides trying out your old M3 track tires) __________________ 2009 135i \| space grey \| sport \| navi \| hifi \| heated dinan stage 2 software \| bmw performance exhaust kw v2 \| hotchkis front sway \| vmr v710
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09-11-2009, 11:52 AM	#3
m3bs Captain 62 Rep 657 Posts Drives: 95 S54 M3, X5, GT4, GR Corolla Join Date: Feb 2008 Location: North Augusta, SC iTrader: (1)	Now that the roll is under control with stiffer springs, going back to the stock front bar might help, although I do like the stable feeling it provides on the street. Beefing up the rear bar might also help, but I'm afraid it would only aggravate the traction control nannies by further unloading the inside wheel. Yes, same RFTs for the initial runs yesterday, although I did swap sides since the LF took a beating last time.
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10-18-2009, 12:35 PM	#4
heyimsam Second Lieutenant 15 Rep 208 Posts Drives: 135i Join Date: Apr 2008 Location: orlando iTrader: (0)	I think it is time to start looking into getting the m3 suspension bits! I heard they really help with turning in a more responsive feedback, and I think that could help with the pushing
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10-19-2009, 07:37 AM	#6
m3bs Captain 62 Rep 657 Posts Drives: 95 S54 M3, X5, GT4, GR Corolla Join Date: Feb 2008 Location: North Augusta, SC iTrader: (1)	I'm currently running 2 degrees. I probably won't make any other changes, as I'm contemplating selling the car to fund upgrades to my M3.
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