Kieran O'Quick Posted November 24, 2016 Share Posted November 24, 2016 Just a performance question really. I'm doing Hill Climbing on a Clubman's budget. On a twisty track, lots of second gear exits. The Zed spins up road tyres pretty easily and that asks questions of the standard diff. Which by now is usually (as in my case) an open one. What I'm wondering is, would trackday tyres lessen this effect? And to what degree? As in, MPSS with a crap diff would do a certain time. With a good diff they'd do a better time. But would good trackday (List 1B) tyres beat that time even with a bad diff? And is a good diff even necessary if you have surplus grip? What's the best way to spend a grand given this choice? Quote Link to comment Share on other sites More sharing options...
Ekona Posted November 24, 2016 Share Posted November 24, 2016 Always tyres first. I agree, a decent diff will help, but you'd still need to be able to put the power down first regardless. Quote Link to comment Share on other sites More sharing options...
Kieran O'Quick Posted November 24, 2016 Author Share Posted November 24, 2016 Always tyres first. I agree, a decent diff will help, but you'd still need to be able to put the power down first regardless. Interesting, ta. My hunch was along those lines. It seems to make a lot of sense. Our cars are obviously overpowered - why else would they come with traction control as standard? So grip is the biggest issue. It's probably the way with most performance road cars. I've been competing all year against a guy in one of those V8 M3s and it's silly how little grip either of us has - especially him, even with a good chassis though. Quote Link to comment Share on other sites More sharing options...
Jetpilot Posted November 24, 2016 Share Posted November 24, 2016 (edited) Traction control is a safety measure in an effort to reduce loss of control, not aid traction. What tyre sizes are you running? Also interesting to note Andy James has recently posted with regards to his next season of hillclimbs and sprints and in a bid to be more competetive, a diff is the first thing on his list, but of course you want the best tyres for the job first. Edited November 24, 2016 by Jetpilot 1 Quote Link to comment Share on other sites More sharing options...
docwra Posted November 24, 2016 Share Posted November 24, 2016 Only thing Id wonder is if track tyres will get up to temp on a hillclimb ............ Diff will make a difference (lol) but ultimate grip will be down to whats touching the tarmac. Alignment is worth thinking about too, you can create more mechanical grip by running toe. Have you experimented with different pressures too? Quote Link to comment Share on other sites More sharing options...
brillomaster Posted November 24, 2016 Share Posted November 24, 2016 id say tyres before a new diff. our track car with an open diff and cheap road tyres will spin up and inside wheel no problem when exiting tight corners. put decent tyres on and you can't spin the rear wheels at all, regardless of what you do. its somewhat boring, but considerably better for traction and thus times. Track tyres make a huge difference. And if you want to upgrade on the cheap, MOT motorsport have some great deals on Federal 595 RSRs albeit in slightly different sizes to usual. http://www.motmotorsport.co.uk/federal-595rs-r-18-c.asp Quote Link to comment Share on other sites More sharing options...
Ekona Posted November 24, 2016 Share Posted November 24, 2016 Only thing Id wonder is if track tyres will get up to temp on a hillclimb ............ Very good point. You'd either need to warm them up first in blankets or by arsing around in the car park, or pick something that's more of an aggressive road tyre rather than a trackday special. That said, given the OEM use I'd expect the MPSC2s to be the best of both worlds, however pricing is going to be an issue here. Quote Link to comment Share on other sites More sharing options...
Kieran O'Quick Posted November 24, 2016 Author Share Posted November 24, 2016 All very good points gents. The car had a track alignment done a couple of years ago so that probably needs a refresh. I did all last year on MPSS standard sizes. Mucked about with dropping pressures throughout the day which definitely helped. I was all set to get a diff to improve things next year but they're changing the regs to allow stickier tyres next year. But as Docwra says it's going to be hard to get an extreme track tyre warm. No blankets allowed. They used to allow burn-outs before the line but they were banned last year. My PB launch time was done when burnouts were allowed - never got within 0.15 of it all last year Well one way or other, I'll be at least able to gather some real world data... Quote Link to comment Share on other sites More sharing options...
Jetpilot Posted November 24, 2016 Share Posted November 24, 2016 (edited) No blankets allowed. So the same for everyone then and i would bet they are using the stickiest tyres available. I would certainly suggest you perhaps get something a little wider (still lightweight) so you can run a 275, that will help no end with traction. Edited November 24, 2016 by Jetpilot Quote Link to comment Share on other sites More sharing options...
Richf Posted November 24, 2016 Share Posted November 24, 2016 Two crap tyres vs one good one is basically the decision. Diff imo , the difference in the way that my 370z launched on the drag strip between the standard VLSD and a quaife was night and day even with the same tyres , MPSS and no burnout . Quote Link to comment Share on other sites More sharing options...
brillomaster Posted November 24, 2016 Share Posted November 24, 2016 can you afford R888Rs? don't they come in various compounds, you'd obviously want the stickiest compound for maximum cold tyre grip. or look at what tarmac rally cars use, they have to operate effectively from cold. Quote Link to comment Share on other sites More sharing options...
Jetpilot Posted November 24, 2016 Share Posted November 24, 2016 The old 888's had different compounds but think the new r888r only come in one compund. Ns2r's are available in different compounds and the new ar1 is worth a mention, i have a rear pair (awaiting the new size releases for the fronts) and are very impressive. Quote Link to comment Share on other sites More sharing options...
Kieran O'Quick Posted November 24, 2016 Author Share Posted November 24, 2016 can you afford R888Rs? don't they come in various compounds, you'd obviously want the stickiest compound for maximum cold tyre grip. or look at what tarmac rally cars use, they have to operate effectively from cold. Just looked at the price of them - I may choose to believe and join the Nankang converts. Two crap tyres vs one good one is basically the decision. Diff imo , the difference in the way that my 370z launched on the drag strip between the standard VLSD and a quaife was night and day even with the same tyres , MPSS and no burnout . Interesting stuff, ta. Quote Link to comment Share on other sites More sharing options...
brillomaster Posted November 24, 2016 Share Posted November 24, 2016 given the list of tyres, and the budget consideration, i'd definitely be looking at federals, get them in a 255/35/18 for the rear which would give you oodles of grip, and a slight gearing reduction for a bit more snap out of corners. and at less than £100 a tyre they're a cheap upgrade, and will last for ages. I've done 8 full trackdays on a set now and they still have 3mm tread, and are still grippy. although thing I've just thought of... is the reason you're spinning an inside wheel because of the camber on the road going through tight uphill turns? in which case maybe consider modifying suspension and reducing rear swaybar to make sure the tyres stay in contact with the ground? Quote Link to comment Share on other sites More sharing options...
Kieran O'Quick Posted November 24, 2016 Author Share Posted November 24, 2016 Good info on the tyres there, thanks. As for the ARB, you're right, an experienced hill-climber did mention that to me. He reckoned just dis-connecting the droplinks was the way to go. Have to say, I haven't tried it. The problem is there are so many mods you can do to get competitive and chase times. But it all comes to nowt if someone enters against you with a huge spend. I'm trying to be really disciplined with the goal-setting and not worry too much about others. Sounds a bit defeatist but at the end of the day the Zed is probably (ok definitely) the wrong car in the first place. It's just fun getting it out there and giving it some. A well-developed SC Zed would be very competitive however... Quote Link to comment Share on other sites More sharing options...
Jetpilot Posted November 24, 2016 Share Posted November 24, 2016 Great attitude to have, its about the laughs, there will always be someone faster than you on the most part, theres plenty that talk a good game but at least your out there doing it 1 Quote Link to comment Share on other sites More sharing options...
nissanman312 Posted November 24, 2016 Share Posted November 24, 2016 I run a quaife and it is good it's quiet aswell However if you lift a wheel it acts as an open diff as its relying on tourqe to shift grip Don't let put you off though great bit of kit for regular use 1 Quote Link to comment Share on other sites More sharing options...
docwra Posted November 25, 2016 Share Posted November 25, 2016 I run a quaife and it is good it's quiet aswell However if you lift a wheel it acts as an open diff as its relying on tourqe to shift grip If you lost the rear ARB that would probably resolve that straight away Quote Link to comment Share on other sites More sharing options...
nissanman312 Posted November 25, 2016 Share Posted November 25, 2016 I run a quaife and it is good it's quiet aswell However if you lift a wheel it acts as an open diff as its relying on tourqe to shift grip If you lost the rear ARB that would probably resolve that straight away Is that a good idea ? Can definitely see a argument for softening the back up tho Quote Link to comment Share on other sites More sharing options...
docwra Posted November 25, 2016 Share Posted November 25, 2016 Quaife is the easy option for 1 series BMW LSD's (i.e. not the one I too ) and EVERYONE from Quaife themselves downwards recommends running a soft rear ARB to try and prevent wheel lift. Whether it would be a good idea on a 350Z is something I couldnt answer, I wouldnt have wanted to do anything with mine as I found it very well balanced on OE ARBs Quote Link to comment Share on other sites More sharing options...
nissanman312 Posted November 25, 2016 Share Posted November 25, 2016 Very good point atm I'm running Kwv3 and Ebaich anti roll bars Car feels great possibly not making the most of the diff tho as you say Quote Link to comment Share on other sites More sharing options...
Ekona Posted November 25, 2016 Share Posted November 25, 2016 How do you have your ARBs setup though? Quote Link to comment Share on other sites More sharing options...
nissanman312 Posted November 25, 2016 Share Posted November 25, 2016 (edited) How do you have your ARBs setup though? As recomended by bennet i think it was the middle hole on the back but i cant remember to be fair! certainly wasnt the stiffest setting bennet had a play in my car the other week and said we can defo go more pointy on the geo while sliding round a island and shouting look still under steer Edited November 25, 2016 by nissanman312 Quote Link to comment Share on other sites More sharing options...
Ekona Posted November 25, 2016 Share Posted November 25, 2016 Sounds like Bennet Quote Link to comment Share on other sites More sharing options...
Kieran O'Quick Posted November 30, 2017 Author Share Posted November 30, 2017 (edited) Bit of data at last. In the first round I went with some mid-range tyres and a Kaaz 1.5 but was slower than last year. I put that down to the slightly heavier wheels they were on. Next event, put R888rs onto the Rays. Previous year's best was 67.82 over the full season. Matched it on the very first practice run on a cold track. Got it down to 66.39 after 3 more runs. Last run was quicker but didn't bring it home.. Finished the year with a best of 66.17. Really annoyed not to get into the 65s tbf but it was bloody great fun trying. I found lower pressures (28) gave great launch times (2.55 sec 60 feet) but struggled a smidge for lateral grip and hammered the tyres. They look pretty funky now. Higher pressures (34) cornered really well but launched slower by a tenth or two which adds up to quite a bit in the second sector too. Absolutely no warming allowed - I tried to sneak a bit of heat in on the way to the line early on in the year but got told off for excessive weaving and braking . To be fair the eagle-eyed Marshalls take no crap - as it should be. Here's a short comparison of two corners with the different setups to listen to. Hope it helps anyone wondering about diffs. http://youtu.be/6K_ikK5caDk (God I'm thick when it comes to this embedding .. Edited November 30, 2017 by Kieran O'Quick Quote Link to comment Share on other sites More sharing options...
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