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Jack

ABS on V6 Cup too intrusive?

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Has anyone experienced "overly intrusive" ABS intervention when running very sticky tires (i.e., grippier than the standard Corsas)?  Late braking and going to "full retardation" can prove problematic at times.   ;)   I can adjust my braking style to avoid ABS, or perhaps I need to deactivate the system and give it a try. As it stands,  ABS and modified braking style is costing me time on track. 

 

I know that Motorsport's position will be that the ABS system used on the V6 Cup  was designed around the Trofeo tire; and, when using "slick-type" tires, a motor-sport adjustable ABS system or a dual master, non-ABS setup with bias adjuster may be required (as installed on the Lotus GT4 variants).

 

Would love any input on the subject.

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I've only really felt it kick in once on my car so I couldn't call it 'too intrusive' with the Trofeo tyre on. That said, I don't push my luck on track days, I have another car for that and I like the shape my car is in now!

 

I'd say it would be worth talking to one of the race teams but they race with the Avon ZZR, a treaded tyre very similar to the Pirelli Trofeo in terms of grip.

 

These guys might be able to help. 

 

http://www.track-group.com

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Whilst not a Cup, I've had the car ABS once on Hankook Z221 Semi Comps, but that was really only when the tyres weren't up to temp, I'm pretty aggressive on braking and have not noticed an issue.

 

That being said, I don't have the two-piece rotors.

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Thanks, Matt.

 

Out of curiosity, what size (and compound of) Hankooks are you running?

 

The 'kooks' are sticky tires -- we ran those as a "spec" tire one season in Lotus Cup USA.

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Hi Jack,

215/45/17 and 265/35/18 in medium compound.  

 

Really impressed with these tyres as a step up from the corsas which, to be honest, I struggled with as I found the soft sidewalls a little unsettling for the track.

 

Have only done the one session so far, so a bit early to say what tyre life looks like.

 

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Interesting comments re Corsa. Were you I the LTS spec tyre - I belive he difference is they have a stiffer side wall?

Just switched from Trofeo to Corsa for a week of track days I was hoping to have a single set of rears last all week.

With regards to ABS, only hit it once on track, also put down to cold tyres where I had not reduced pressure on first session of a cold day.

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Hi Tom,

No - these were the standard Corsa's as fitted to the car, I don't believe they're a "special" for the car.  The sidewall was like a marshmallow :)  

That being said, the rubber has plenty of grip, it's just the 'feel' of car I struggled with.  With an AD08R, RE-11 or similar tyres which has the stiffer sidewalls, I think you'd find they would provide a similar feel as the semi's but without the same wear rates of the semi comps.

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I only ask as was debating with a friend the importance of the LTS designation when he found a cheap supplier of Corsas. Turned out they were correct, but also discovered the difference with non LTS was sidewalk stiffness.

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Yeah - I reckon if you could get an LTS designated corsa, that'd be perfect.

 

That being said, the corsa has a UTQG of 60...  Which from a life perspective, they definitely won't last much longer than the Trofeo's (Which have the same tyre rating).  

 

FWIW - The AD08R, RE11's etc have a UTQG of 180 and arguably, better grip.

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Sorry - early and on phone, not sure I am making my point. There is a LTS designated Corsa, and the difference between that and the non LTS Corsa is that it has stiffer sidewalls. Can't for the life of me find the website where it had the details.

Having run "sticky" Trofeo do date I am concerned that the Corsa will be noticeable, paticulary after your comments. Spa today - will be interesting. But very wet so probably not a good day to compare.

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All good - I got your point :)

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I actually thought the Trofeo's were softer side walls than the Corsa's?

 

Trevor.

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I can't find those sizes for the Z221 semi-slicks in the Hankook catalogue.  Closest I've found -- 225/45/17 front and 275/35/18 rear. :(

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Hi Jack,

Try this:

Medium Compound part numbers.

215/45ZR17W   1012647                                                                                    

265/35ZR18Y   1012651                          

 

From here:

http://www.hankooktyre.com.au/Product/MotorsportTyreSemiSlick.aspx?pageNum=1&subNum=5&ChildNum=3#Z221                         

Edited by Bloke79

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Hi Jack,

Try this:

Medium Compound part numbers.

215/45ZR17W 1012647

265/35ZR18Y 1012651

From here:

http://www.hankooktyre.com.au/Product/MotorsportTyreSemiSlick.aspx?pageNum=1&subNum=5&ChildNum=3#Z221

Thanks.

I see the problem .... I was looking at the Z214.

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Just a follow-up on my ABS issue:

 

As mentioned above, the Yokohama slicks obviously increase the car's braking potential as compared to the Corsas that come stock on the Cup. G's well in excess of 1.1 under braking are possible.  However, after looking at my data, it appears that the ABS system on the V6 Cups were programed with ~1.1 Gs as a max .... above that threshold the system must think I'm in lock-up and trying to help by altering brake pressure and resisting my attempts to retard acceleration.   :)

 

I've recently de-activated the ABS for some testing and for my "track-only" use (bear in mind that the CUP R w/sequential doesn't get DPM), the car is much more predicable under hard, late braking.  My lack of confidence before when I was unsure when, and if, the ABS system would do its thing was really messing with my head and causing me to brake much earlier and lighter than ideal for minimizing lap times.   ;)

 

IMHO, a track-only car sold by Lotus Motorsport should come with a dual master cylinder/brake bias controlled setup or, if sold with ABS, a Bosch or Teves motorsport ABS system.  Of course, either option  would increase the price, but I would have gladly paid it to Lotus.  Instead, I must have it done after delivery at a greater expense (most likely)  and Lotus loses out on making some extra profit ..... go figure.

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Glad to hear you've found a way round it.

 

The thing is, the CupR races on Avon ZZR road legal tyres over here and in Europe so I guess the factory didn't need to get into a slick tyre set up. I did hear that the Ohlins TTX dampers are also not set up for slicks so there might be a bit more optimising to do yet with possibly higher spring rates. It will be some car when you've finished though!

 

Any video of your track sessions to share with us yet?

 

I'm off to Goodwood tomorrow and the weather's looking good. For me it's great to have a road legal tyre that I can drive to the circuit on that still holds up well to track use. My front tyres are finally on their way out so it will be interesting to see if the ABS starts to kick in more often.

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Glad to hear you've found a way round it.

 

The thing is, the CupR races on Avon ZZR road legal tyres over here and in Europe so I guess the factory didn't need to get into a slick tyre set up. I did hear that the Ohlins TTX dampers are also not set up for slicks so there might be a bit more optimising to do yet with possibly higher spring rates. It will be some car when you've finished though!

 

Any video of your track sessions to share with us yet?

 

I'm off to Goodwood tomorrow and the weather's looking good. For me it's great to have a road legal tyre that I can drive to the circuit on that still holds up well to track use. My front tyres are finally on their way out so it will be interesting to see if the ABS starts to kick in more often.

  Thanks, Jonny.    Have FUN at Goodwood!  Keep the shinny side up.   ;)

 

You are, of course, correct that my car was set up to run on R-comp tires.  In reality, the CupR is really just a Cup with some additional aero, Ohlin TTX shocks, some weight reduction, A/C delete and no trunk.   :)  Adding the sequential option did make my car a bit more unique.   As for the Ohlins, they appear to working out OK right now, but I'm sure they would benefit from being re-valved.  As for spring rates, I can't imagine I need more than the 969 (front) and 1283 (rear) lb/in springs that are on the car now, even with slicks.   :no

 

As for  track videos of the V6, there are a few up on my youtube channel .... here's a link to one .... before the abs defeat, so braking early and with less gusto.   :D

 

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