2011 Evora S - Chasing lap times, while not destroying everyday's qualities (too much)

[Friss]

What is your ride height set at with the nitrons? 

Are you sticking with the default -10 (middle) damping setting?

[jerzybondov]

Do you guys leave your engine cover on or ditch that to save a bit of weight?

[Bibs]

Mine's on still. It's not a pretty engine! 

[Bruss]

4 hours ago, jerzybondov said:

Do you guys leave your engine cover on or ditch that to save a bit of weight?

Ditch mine to let the heat out.

 

 

[Bravo73]

^^^^This^^^^

[#84]

I take out the engine cover on track days - to let the heat out. Otherwise I have it on for the same reason as Bibs.

[#84]

@Bruss - So with full tank and without you it means 1349 kg (752 g / liter). Your standard 19/20 are 1,5 kg lighter than my standard 18/19, but I guess the tyre dimensions evens out most of it. Mine with full tank and floor + diffusor + Head unit mounted then ends up at 1404 kg, which is 55 kg up. It sounds like a lot on seats, HiFi and brake discs. If it is right, must add more to my to list than just the brake discs ...

 

FYI, I checked the Alpine data sheets I have downloaded:

The head unit is 2,9 kg

The nav unit is 265 g

The sound processor is 345 g

The original sub-woofer is only 800 something gram and the amplifier is just a few hundred grams.

Edited August 23, 2021 by #84
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[#84]

@Friss I did set it up with the same ride height as I had with original Bilstein's, which is close to nominal 125/147. With the race wheels I end up at 120/137 with new tyres @ 2,2 bar and 75 % fuel. No driver.

On track I found a significant improvement in chassi control when I stiffened up. My starting point was -12/-10, but it does not work at all. The rear needs to be 1-2 clicks softer than front with my 900/1100 springs. My last dry track day performed best at -5/-6, but felt better with -6/-7. It started to rain slightly, so I do not know if it was faster a click softer. In wet I have to keep the relation F/R and can soften up a click or two. With rear ARB disconnected one can shift to the same setting F/R - in wet and with my spring ratios.

What do you run?

 

[Friss]

I need to measure my height, but I run it lower than the stock height. 

I've run a few track weekends at -10 front & back but going to start testing running it stiffer and seeing how that feels. Though you are running different spring rates than I am as well.

[#84]

That is quite a different spec of those Nitrons, I guess they are not the Hofmanns Race 46's. Or? If not, the relation between compression and rebound damping is different and probably the characteristics in total.

If you haven't elaborated on the settings yet, I recommend you to bring  proper floor jack to the next track day. I lift in the rear lifting point and adjust both front and rear on that side at the same time. Super quick. And write notes. If the car feels balanced as it is, just change both F/R 2 steps at the time, then when you do not find more improvement, start split the settings apart F/R. If it is like in my case, I did it the other way around, found a F/R balance that worked, then shifted them both to stiffer 2 steps each time. Followed by fine tuning.

[Friss]

Yeah I'm across the pond and ordered them through GregRaceParts. Mine are the single adjustable "track edition" vs the 400/500lbs "road edition". 

I've found the -10 stock all around to be quite nice but figured it was a good time to start twisting the knobs and dialing it in some more. Luckily I always bring a jack to the track. 

[#84]

Slow in updating this thread lately.

Priority one is to drive

Priority two to improve driving = modifying the car

Priority .. something .. to spread the message. Sorry for that.

It has been a lot of things going on lately. A few track days, some cancelled, several updates, problems, a lot of other things taking time, a few track days left. Well, minimum one.

So, just to make a hint about what's going on, two pictures:

[#84]

Time to summarize the 2021 season and all elaborations on chassie settings.

The ambition was, as always, to drive more trackdays, but also, as always, parts deliveries messes it up. Let's start with a table showing what was tested:

BWR is Blackwatchracing, in US, the only adjustable anti roll bar (ARB) for the Evora, that I could find on this planet. It has three holes in each end, which means you can make 5 combinations. 3-3 means outermost hole on both side, which is the softest setting and about 25 % up from stock. BWR were super quick to deliver, but shipping + custom fee + VAT on top, was unpleasant... https://www.blackwatchracing.com/Evora-Adjustable-Anti-Roll-Bar-p/1008.htm

H.Race is HardRace. Bought from a Swedish distributor. Unfortunately long lead time, which meant I could't fit the BWR ARB either, until July. https://www.hardrace-europe.com/end-links.html

Damper. The Nitron R1's have 20 clicks and you count from fully closed (hard).

Overall, I can say that I have driven more or less every available minut, changed settings between each session and also going into pits during some 20 min sessions, lift the car and change damper settings in all 4 corners. So quite ambitious.

Findings

• Knutstorp May 7
  • Probably the most scary track day ever for 25 years, at least to start with and when it was 9 C in the morning
  • I later found out that the rear Kumho V700 K91's had got too many heat cycles
  • Essentially the car was well planted and very stable at steady state cornering, but super loose in the rear at slightest acceleration
  • Sector times showed very big variations, about 1 s, while I normally are within 2 tenth, never over 3 tenth. So, difficult to produce a clean lap.
  • Most of the day was much slower than normally, but in the end I shaved off 2 s from personal best on a 70 s lap
  • Changes for next track day: New rear tyres. Adjustable front anti roll bar. Adjustable ARB drop links all around. Lower the rear end a fraction of a mm.
• Sviestad Aug 7
  • First time with the Evora here. We drove a rarely used track layout, so difficult to compare lap times, but quick relative to the others. 🙂 
  • In the end I found -6/-7 to feel best, but it started to rain. One click F or R made a very noticeable different.
  • Very good in wet.
  • The trade off was between traction and understeer.
  • Changes for next track day: Try to loosen up the rear end to get better turn in. Test with rear ARB disconnected. Try with other spring rates?
• Knutstorp Aug 17
  • Rain all day. The new springs didn't arrive in time and my original plan to move the front Nitron springs to the rear didn't work out.
  • It was for sure quicker with rear ARB disconnected, but more on/off in its behavior.
  • Unfortunately one almost new front disc cracked and Brexit messed up delivery, so next trackday at Anderstorp old F1 track was cancelled
• Ljungbyhed Oct 15
  • Rain all morning. Did all driving and testing, 5 settings, in 3x20 min. Phone broken, so no data logging.
  • This is an old airfield with a lot of short radius 90 deg bends, so rapid steering input and quick on throttle
  • I had decided to pull the spring rates apart, from 900/1100 to 600/900 to be able to play more with the from ARB settings. More like OEM setup.
  • I never found a working setup and ended up in the hardest end of the adjustment range, which was where the dampers doesn't work very well.
  • Constant struggle to balance between traction and understeer. Body roll was also an issue before tightening the dampers up, but 2 s below personal best.
  • Conclusions: Need for MORE front negative camber and change the damper valving towards stiffer. Maybe the 900/1100 springs, or x00/1100 had worked better here?

End of season

 

Edited January 20 by #84
more info

[#84]

So, to summarize what was achieved and what could have been achieved, I think the following is fair to say:

In pure facts no better than 2 seconds per 60-70 s lap was gained over stock chassis. If I on the other hand look on the details, if I had decent rear tyres the first trackday, more predictable behavior and better confidence could bring almost one second more (as seen from sector times) and better traction in itself would bring at least another half a second (yes it was that bad). In total this means 3-4 s per lap, which is what I see others gain on mid priced coil-overs on comparable cars. Sorting out spring rates and damper characteristics should bring the chassis to a level beyond normal off the shelf coil overs, close to top of the range solutions.

The second track day was amazing pace wise in relation to drivers/cars I meet on other tracks, so given the right type of track, it is obvious that the potential is there.

In behavior, what remained the issue was understeering v.s, traction. Understeering appeared both as turn in and mid-late corner push, not both every time. It was however clear that the single most important contributor to improved lap times was body control. This goes quite well with the disadvantageous tempretaure profiles seen in the tyres, limited negative camber and heavy body roll, which limits the standard chassis. When body roll can be controlled much better, the temperature profiles looks better and you can push a little harder before the camber limits you.

Damper wise, the feedback I got from the supplier when summarizing the season was that all my lap time optimal settings were out of the dampers comfort range. When I tried -3/-1 during the last trackday, it was totally impossible to not notice that it didn't work at all. Well, it is good to have tried. But even running at -6, might reduce the performance and contribute to things such as inner rear wheel spinning.

Finally, when attending a serious trackday with proper track tools (GT3 RS, F8 Tributo, AMG GT-R), etc, it is clear that they all run about one more degree negative camber, they have excellent body control and many have an impressive capacity to swallow the curbs. If you sort that out, you can start to think about 375 hp vs .... hp.

Next organized post will be about ongoing modifications.

[jerzybondov]

Great updates 84! I love your dedication to the cause. Some might have said it would have been easier to just swap the car for a Sport 410 or Exige 😉

How différent is the ride on the road on the new suspension?

[#84]

Thanks @jerzybondov! Well, I made the assumption that it would be pretty straight forward bolt on and some tweaking of the settings. Not really 🙈 At least I enjoy the process, even though not all the extra costs and delays.

The first impression was quite nice. Firm, not harsh and very direct and communicative. It can take compression impacts very well, but in droop (rebound) it cannot handle even a top surface (like a 2-3 cm deep pot hole) damage to the road. The ride quality is very poor if the road isn't close to perfect. Gravel roads are a complete no no. But I am very confident that this will be sorted out the coming weeks, in time for the first track days in April.

[#84]

One of the ongoing upgrades. AP fully floating system. 250 mm bar ordered.

[#84]

Another upgrade that is kind of ongoing. Should have been done long time ago. They were at least painted last winter. The idea is to make a bracket for the wheel arch liner as well as fit a metal mesh.

 

[#84]

Quite an efficient evening. Nitron R1's ready to be shipped back to Nitron for rebuild to R3's with Hofmanns specification.

One more thing prepared, but that is for my next post 🤫 

[jerzybondov]

Enjoying these updates!

[#84]

I also removed one upper wishbone from the front suspension. Both sides are maxed out in camber at about -1,5° and clearly runs too hot on the outer section at trackdays. Normally much worse on the left side. I have a few options with regards to technical solution, but have more or less ruled out making new wishbones due to time and/or cost. The shape is such that it is not a quick job and the company who makes for Exige's quoted a price which clearly should carry all design and setup cost for a small series. And signing up for a small series was the next show stopper.

So, I will return within short with more details.

 

[SZ]

Maybe you should follow this thread.  https://www.lotustalk.com/threads/2022-evora-front-upper-control-arm-group-buy.487042/

[#84]

Thanks for the advice @SZ I follow LotusTalk every now and then, but obviously not often enough. Anyhow, the parts arrived today and the bushing extractor I made seems to work. My solution will allow up to -2,75 deg camber based on -1,5 when it is maxed out now. My target was 3, preferably 3,2. I will give it a try and will probably introduce it in the rear suspension as well. The spherical bearings aren't cheap and it will require some machining time + assembly effort, so all in all a plug and play solution would probably be desirable. 

[#84]

Quick and dirty DIY bushing extractor. A 42 mm (1 1/2") hydraulic pipe with a welded cap goes inside the wishbone and a 2 1/2" OD, 2" ID, pipe holds up against the wishbone structure. 90 C for 30 min in the oven (which explains the thick gloves ...) + some oil and it went well, even though they required a massive force. I do however not know if it was benefit to heat it up since it appeared that the bushing outer structure was made of some hard plastics, which probably have a higher thermal expansion coefficient than Aluminium => Just makes things worse 🤥 I thougt it was steel.

I hope I get the Delrin / Acetal C rods by the beginning of the week and can start manufacture the new bushings. Let's see. Away Thursday-Sunday.

 

[#84]

An advice for those considering fitting 46 mm Nitron's, or dampers of equivalent size: The rear lower wishbone's damper "yoke" is super-tight and has sharp edges. Besides making installation/removal a bit awkward, it will cause scuffing marks on the damper tube when the bushings flexes and the wishbone moves. Those edges are belongs to a completely unloaded part of the structure and can be grinded down, without compromising the structural strength.