Body Roll

[elenitro]

I had a great 1st track day yesterday @ donnington, just kept getting a bigger and bigger grin on my face with each lap, but being me, found and exceeded the limit of my tyres (R888's) luckily where there were no barriers or gravel (Craner Curves). I was looking at the pics and thought the amount of body roll didn't seem normal.



Is this normal? If so what's the best thing to do to 'firm' things up for next time?

It seems as well that the standard brakes (newish discs and pads) can't cope with 3 sessions (1 20 mins per hour) and turned to 'mush' with fluid seeping out of the reservoir, a 'very' long brake pedal and hot wheels! What's the best thing to cure this? replace brake fluid with 5.1? braided hoses?

Leon

[david.mt]

Does seem excessive body roll - this is one of mine at Cadwell. It will be a slower corner but still giving it some beans.



I have changed to grooved discs all round and track day pads (Pagid) and they have been fine for both track and lots of fast road use.

[JLSELAN]

Body roll is normal IMO, especially considering that the cornering "line" the car is on does not appear to be ideal.
Remember, the car is relatively softly sprung to give a good balance of road and track comfort and feel. The M400 set up is somewhat more track oriented while, in general, the M12 is more focused on high speed touring.

[Boosted LS1]

I'd hazard a guess the roll bar's to stiff as it looks like the nearside rear wheel's lifting? I could be wrong though

[JLSELAN]

No front roll bar in stock M12s.

[Boosted LS1]

Thanks, I didn't know that. Could there be to much stiffness elsewhere, front springs maybe? Is the rear wheel lifting?

[mgbond]

Stock 2.5. Looks fine to me.

http://i73.photobucket.com/albums/i208/mgbond/Acad...

Bondy

[daddysumo]

It probably does not have decent fluid in it as standard.Mine was dealer maintained and they use standard brake fluid in a braking system that is all AP and braided hoses etc.....go figure, they say the average owner wont pay for the good stuff !
My pedal went to the floor on the pit straight at Donny, used RBF and next time was better but still long travel.
I have been recomended to use the pagids or Ds 3000's so will try these next as well as Titanium backing plates.
I was getting the front end going light and washing out through the right hander through caners on A048's at around 110,upgraded to Nitrons and it now holds on better through the same bend and up to 115 so an improvement but I suspect that aero mods to give the front more downforce is the key. All IMHO of course

Steve

[david.mt]

I have the Pagid RS29 pads which I am really happy with and braking is now limited by the tyres - had forgot that there are usually no anti-roll bars on the M12. The M400 also has stiffer springs and different shocks so the real answer is upgrade to a M400

[jamescmr2]

JLSELAN said:

Body roll is normal IMO, especially considering that the cornering "line" the car is on does not appear to be ideal.

can't see how your position on the track affects how much body roll there is? Surely it is a function of the cornering speed, radius of turn and the car stiffness characteristics. I guess driving style will affect this as well but put a car on a skid pan and that takes racing line out of the story!
Just a thought.

Does look worse than i would have expected but i have no experience on track with my Noble.


Looks really good on track though, love the car in black.


james

[Stella Artois]

jamescmr2 said:

JLSELAN said:

Body roll is normal IMO, especially considering that the cornering "line" the car is on does not appear to be ideal.

can't see how your position on the track affects how much body roll there is? Surely it is a function of the cornering speed, radius of turn and the car stiffness characteristics.

Body roll is a resultant of shifting weight, if on entry to the corner the weight of the car had to be moved from one extremity to the other, (Like a Scandanavian Flick) then there will be increased roll due to the momentum of the transferred weight.

[JLSELAN]

+1 -- in other words, it makes a huge difference in weight transfer being on the "correct", or ideal, line compared to being "off" line.

Edited by JLSELAN on Thursday 3rd September 03:32

[Pinnacle]

Here is a un scientific comparp from the US VIR event last summer, where I tried to show the body roll between a stock 3R suspension (lots of roll), stock M400 with less (has front roll bar), and my much modified 3R still with no front roll bar. It does have upgraded M400 shocks, and upgraded springs on all 4 corners. In any case, interesting

OK, this is not very technical, but since we had some photos from ALMOST the same spot on track, and from 3 different car set ups, I found this interesting when reviewing body angles relative to roll, squat, and so on.

First shot = stock 3R suspension

Second shot = stock M400 suspension

Third shot = stock 3R geometry, modified / stiffer suspension spring rates and shock valve rates, which is stiffer than the M400 by a percentage.


Just found the comparo interesting, albeit not very technically done.

[AMG Merc]

Pinnacle said:

albeit not very technically done.

Good enough though, thanks

[elenitro]

Thanks guys, now i've seen other pics, then as I also had a passenger on board I don't think it's anything to worry about!

Still concerned about the brakes though but it sounds like perhaps groved front discs should help over the standard ones, but would the rs2900 make that much difference over the EBC yellowstuff ones i've got? I also noticed that there was some fluid leaking out of the bleed valve on the front o/s brake. btw does a 3r have decent brake lines as standard? if so how much work is it to bleed the system and replace the fluid with proper stuff?

Leon

[rort1]

Heres a comparison - taken at donington a few days earlier (apologies for the 'arty' angle!)

this is a 3r with nitron single adjustable

R

[Dave2P]

rort1 said:

Heres a comparison - taken at donington a few days earlier (apologies for the 'arty' angle!)

this is a 3r with nitron single adjustable

R

Is this picture proof that an M12 can exceed 1g? That's one hell of a reverse camber anyway...

[Pinnacle]

elenitro said:

Thanks guys, now i've seen other pics, then as I also had a passenger on board I don't think it's anything to worry about!

Still concerned about the brakes though but it sounds like perhaps groved front discs should help over the standard ones, but would the rs2900 make that much difference over the EBC yellowstuff ones i've got? I also noticed that there was some fluid leaking out of the bleed valve on the front o/s brake. btw does a 3r have decent brake lines as standard? if so how much work is it to bleed the system and replace the fluid with proper stuff?

Leon

Leon, agreed nothing to worry about with the suspension unless you really intend on pressing the car. As regards the brakes and lines on a 3R, I continue to run stock brake lines with no issues even when pressing hard on track. I and others have upgraded to grooved discs, and with me, grooved discs on all four corners. MASSIVELY HUGE difference in my eyes, as relates to almost no brake fade, i.e. stiff pedal under track conditions. Can't comment with official knowledge on the EBC Yellowstuff pads, but I would suspect they are no where near sufficient. I would either stick with stock AP pads, or upgrade to Pagid or Ferrodo pads if you upgrade the discs. I have Pagid r29's with my grooved discs, and they are the ST !

Your brake line bleed valves should NOT leak, so I would be looking into that soonest, as a little brake fluid goes a long way, especially all over your nearby tyre and slippity slidy you go off the road or track ! Although it takes some time to flush the fluid, it is not hard. Just takes patcience, and working to bleed from the furthest caliper from the resovoir first, then progressively back to the front of the car to ensure you get all used oil out, and then all air out when done, if any. I would further add for street use, you should flush the brake fluid once each year regardless, and more frequently if tracking hard.

This brings to mind another point. Flush your clutch fluid too each year. This is often overlooked, and will amaze you how if affects your shifting smoothness within the gear box, and how the car shifts if you go on track. It will also delay or prevent your clutch fluid getting too hot on track from poor shifting techniques, as with all fluids of this type, they break down over time, and more importantly absorb moisture from the air which will cause the fluid to boil when it gets too hot, which spells air in the lines, which spells poor performance of fluid failure if really bad. True for both the brakes and clutch.

Both flushes will save you multitude of headaches during the ownership of your sweet ride on street or track !

[jamescmr2]

just because i enjoy a good discussion, not being arguementative...

Stella Artois said:

Body roll is a resultant of shifting weight, if on entry to the corner the weight of the car had to be moved from one extremity to the other, (Like a Scandanavian Flick) then there will be increased roll due to the momentum of the transferred weight.

JLSELAN said:

+1 -- in other words, it makes a huge difference in weight transfer being on the "correct", or ideal, line compared to being "off" line.



I agree with what you say about weight trasfer causing body roll. If no weight was transfered the suspension wouldn't change position at all (F=Kx)!
A driver can keep a car settled around a corner on any line they like, not necessarily the fastest way round though. However, being on a poor racing line and fighting to get the car back on line would cause the car to unsettle that's for sure. Agree?

I'm sure i'm being pedantic


cheers all

[Jim O.]

elenitro said:

if so how much work is it to bleed the system and replace the fluid with proper stuff?

Brake bleeding is not a very difficult job, but it's a bit tedious (and it takes two people) to do using the "pump the pedal" method. It's much faster and easier if you use a brake bleeder. I don't know what's available in the UK - over here in the States, Motive Products (http://www.motiveproducts.com/index.html) makes a relatively inexpensive pressure bleeder that works very well, and is portable so I can use it at the track.