Tony Posted April 4, 2009 Report Share Posted April 4, 2009 Try out-out front, in rear? The Evo10 chassis similarity to the 9 is common place.... most manufacturers use an existing successful chassis position to overlap on a newer version, just a few tweaks here and there is all that's needed. Quote Link to comment Share on other sites More sharing options...
CIH Posted April 6, 2009 Author Report Share Posted April 6, 2009 Toe-out rear on 4WD and RWD helped out a lot, especially on an FD RX7. Finally getting the cars to behave how you'd expected a racer to behave. Not how I was expecting toe-out to impact though ? I would have thought it would make the rear more wayward ? IIRC the NSX didn't react well though. Quote Link to comment Share on other sites More sharing options...
Tony Posted April 6, 2009 Report Share Posted April 6, 2009 Depending on the amount of toe out you can induce progressive power oversteer. Quote Link to comment Share on other sites More sharing options...
CIH Posted April 6, 2009 Author Report Share Posted April 6, 2009 yes but I always figured that to be within the realms of toe-in ? Or does that depend on the specifics of a given vehicle ? it's not so much oversteer that's the problem as the back tyres loosing grip due to high engine output and slightly poor throttle control by the "driver" lol Quote Link to comment Share on other sites More sharing options...
Tony Posted April 6, 2009 Report Share Posted April 6, 2009 well spotted.... Historically toe in would be more progressive without "snap" oversteer, but for the track and an educated driver power oversteer with toe-out is more desirable. Even in the game the reason the car seems uncontrollable is your Hz is below the cars control parameters, fundamentally it's the skill to control the car that's missing. We can tune the chassis but we cannot tune the human! Quote Link to comment Share on other sites More sharing options...
CIH Posted April 6, 2009 Author Report Share Posted April 6, 2009 Yeah, Forza is actually more fun if I reduce output to about 300/400bhp and run in a lower class when tuning cars. The upper classes are dominated by the likes of Zondas, Enzos, TVR Speed 12 etc. Quote Link to comment Share on other sites More sharing options...
Tony Posted April 6, 2009 Report Share Posted April 6, 2009 Why do you think that is though...... Be honest? Quote Link to comment Share on other sites More sharing options...
CIH Posted April 7, 2009 Author Report Share Posted April 7, 2009 because even a GTR is a compromise compaired to mid-engined, V12 exotica ? Quote Link to comment Share on other sites More sharing options...
Tony Posted April 7, 2009 Report Share Posted April 7, 2009 because even a GTR is a compromise compaired to mid-engined, V12 exotica ? Knowing that what would you do about it? Quote Link to comment Share on other sites More sharing options...
CIH Posted April 7, 2009 Author Report Share Posted April 7, 2009 play a less annoying game Quote Link to comment Share on other sites More sharing options...
Tony Posted April 7, 2009 Report Share Posted April 7, 2009 play a less annoying game Defeatist .... Roll things back a bit... 0 camber, 0 toe, then add incrementally. Quote Link to comment Share on other sites More sharing options...
CIH Posted April 8, 2009 Author Report Share Posted April 8, 2009 Nah, tuned GTR/Supra/Evo etc just don't make the speed of the Exotics. I think I'll go back to my fast-road, mountain pass roots and trying to get the absolute best time from a more "reasonable" car. That was fun and informative. Had the easiest Camber adjustment I've ever seen today btw. Honda bus (FRV ?), running -15ish N/S and +16 O/S on the front. Hunter reckons "minimal adjustment" can be had from the Mac Strut-to-Hub link. So I crack 'em of, looking/hoping for -20 minutes and the whole-lot naturally moves to -10 minutes, varified by an second castor sweep! Result, and didn't even need an axle lift. Quote Link to comment Share on other sites More sharing options...
Tony Posted April 8, 2009 Report Share Posted April 8, 2009 Result..... Things don't have to be hard, even though out topic is.... Happy days Quote Link to comment Share on other sites More sharing options...
CIH Posted April 9, 2009 Author Report Share Posted April 9, 2009 Meh had another case today of trying to adjust camber away from negative by using the slotted section at the bottom of the strut/top of the hub and found no gains. It was all toward negative. Can we go through roll over camber wear ? And why for some cars a given geo figure wears tyres but on another (hyperthetical) example of the same car it doesn't ? Such as when it's adviseable to more away from OEM ? Quote Link to comment Share on other sites More sharing options...
Tony Posted April 9, 2009 Report Share Posted April 9, 2009 Meh had another case today of trying to adjust camber away from negative by using the slotted section at the bottom of the strut/top of the hub and found no gains. It was all toward negative. Can we go through roll over camber wear ? And why for some cars a given geo figure wears tyres but on another (hyperthetical) example of the same car it doesn't ? Such as when it's adviseable to more away from OEM ? I'll have to get some screen shots tomorrow to help the explanation. Quote Link to comment Share on other sites More sharing options...
Tony Posted April 10, 2009 Report Share Posted April 10, 2009 For your analysis... Actual positions (wheels dead ahead) 20 degree left lock 20 degree right lock What can you see? Quote Link to comment Share on other sites More sharing options...
CIH Posted April 10, 2009 Author Report Share Posted April 10, 2009 Cross camber is inconsistent. Quite a lot too. Oh and I've discovered something interesting in Forza but I don't want to stray off topic just yet. Quote Link to comment Share on other sites More sharing options...
Tony Posted April 10, 2009 Report Share Posted April 10, 2009 What about the castor and toe values?...... I agree there's loads of maths going on there but with your understanding of the SR migration this should make some form of sense. Quote Link to comment Share on other sites More sharing options...
CIH Posted April 10, 2009 Author Report Share Posted April 10, 2009 TBH I've never observed the connection between toe and castor. Or toe and SR for that matter. Presumeably, the N/S tyre seeing so much toe on left turn indicates incorrect SR placement/migration ? Quote Link to comment Share on other sites More sharing options...
Tony Posted April 10, 2009 Report Share Posted April 10, 2009 No.... considering the toe positions were already violated at "DA" then this is not a consideration.... Look at the cross disparities lock on lock? Additional math is the initial camber/ castor/ toe error but this shouldn't be end of days. Quote Link to comment Share on other sites More sharing options...
CIH Posted April 10, 2009 Author Report Share Posted April 10, 2009 Well that only leaves castor So the fairly small cross castor at DA is magnified on lock ? Quote Link to comment Share on other sites More sharing options...
Tony Posted April 11, 2009 Report Share Posted April 11, 2009 Massively, and that's at 20 degrees, imagin what it like on full lock? "roll over" castor do you think. Quote Link to comment Share on other sites More sharing options...
CIH Posted April 11, 2009 Author Report Share Posted April 11, 2009 But castor specifically doesn't cause wear does it ? Quote Link to comment Share on other sites More sharing options...
Tony Posted April 11, 2009 Report Share Posted April 11, 2009 But castor specifically doesn't cause wear does it ? No but it's responsible for so much dynamics it's a major player. It's for this reason i say to staff/ trainees or whoever, the Geom report doesn't mean a thing without that swing Quote Link to comment Share on other sites More sharing options...
CIH Posted April 11, 2009 Author Report Share Posted April 11, 2009 that rhymes.....anyway, so it's shallow camber that's likely to cause problems ? I'd always figured too deep a castor in the past, posabily showing the tyre too much camber on turn but clearly that isn't the case. I imagine it plays havoc with Mercedes huh ? Last one I looked at (an mid 90s E Coupe) had 10 degrees @ DA. I really need to see one on lock as I bet the figures are huge. That Merc was toe-only rear but fully adjustable front, incidentally. edit: seems a bit rubbish the DSP600 has no facility to show SR placement/migration. Quote Link to comment Share on other sites More sharing options...
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