Where's Wally

[fuhrius]

The MM plates are good for a total of 2*. I can actually get more on the right -- probably 2.2*, but left is maxed out at 2.0*. I'm going to pull the front wheels later today and fully inspect the tires before deciding on camber.

Meanwhile, just compared the AIM data for my best Boss (Black trace) versus R (Green trace) laps. Top box is Speed, followed by Longitudinal Accel, Lateral Accel and finally Cumulative time delta:



My observations:
1) R is faster on all the straights by as much as 2.3 mph -- no surprise
2) Mid corner speeds are significantly improved -- Oak Tree (the slowest) is 48.0 versus 44.2mph
3) The only place that the Boss was quicker was the approach to 6 -- but I lifted here to wait for the pass on the red P car (see video)
4) Lateral g's are higher in the R -- no surprise

Now for the interesting piece -- I was braking better in the Boss -- note that in all the braking zones, the Black line dips on the cumulative time chart, also peak braking g in the Boss was 1.25 versus 1.18 in the R. Assuming my interpretation of the data is correct (and it certainly matches my subjective assessment) it looks like there's a bunch more lap time up for grabs with more aggressive pads.

Would love others observations who have more experience interpreting AIM data @ArizonaBOSS

none of that surprises me, including being better in braking zones in the Boss because of a) what you've said about pad material and some fade on day 1 which relates to b) getting used to wringing everything out of the brakes on the R versus your familiarity with the Boss. My only experience driving the R was at the track tour and I came away feeling like the car was going to communicate it's handling limits pretty readily and throttle application was almost a no-brainer...so the learning curve in driving the R quickly was really going to be in maximizing braking.

Like Rick, I'm also going out day one with a stock setup - expect that I did have the car aligned to correct bad initial toe settings (front and rear) and to max front camber - we only came up with ~-1*.

My car is a drive-it-to-the-track car so I'll be sticking with the PSC2's but it's clear that we'll be chewing them up without camber plates. I'll be at LS on thursday if the weather cooperates.

 

[AMPowerJ]

Love this thread! Great info ... Thanks for sharing.

 

[CSL]

Appreciate all the info and data on getting this car set up for the track....thanks and keep it coming! Based on your feedback I think I will scrap the idea of 325s on the rear and go with squared 305s. I'm wondering which wheels you ran the Michelins and Hoosiers on....and was each set staggered 11/11.5?

Also, on another note, I'm curious to hear your impressions on hood flutter and if you think there is a need to address it?

 

[steveespo]

Great work Nick, 2 weeks ago I could only manage 2:12.6 on my worn Pirellis from MPH. Had a hoot though. 21 still has it a little bit on top 150.3 to 149 but Wally kills it all around the twisty bits. Can't wait to get the voodoo child21 on track. Many boxes from UPS have been arriving. See you soon.
Steve

 

[Black Boss]

Great work Nick, 2 weeks ago I could only manage 2:12.6 on my worn Pirellis from MPH. Had a hoot though. 21 still has it a little bit on top 150.3 to 149 but Wally kills it all around the twisty bits. Can't wait to get the voodoo child21 on track. Many boxes from UPS have been arriving. See you soon.
Steve

Steve, Great to hear you had a hoot -- more work for the 21 car though -- 149 was the Boss, Wally hit 151.7 8)

 

[Black Boss]

Like Rick, I'm also going out day one with a stock setup - expect that I did have the car aligned to correct bad initial toe settings (front and rear) and to max front camber - we only came up with ~-1*.

My car is a drive-it-to-the-track car so I'll be sticking with the PSC2's but it's clear that we'll be chewing them up without camber plates. I'll be at LS on thursday if the weather cooperates.

Look forward to hearing your feedback -- hope the weather cooperates. I'd love to run LS again

Without increased camber I'd expect even more understeer in addition to tire wear -- let us know......

 

[Black Boss]

Appreciate all the info and data on getting this car set up for the track....thanks and keep it coming! Based on your feedback I think I will scrap the idea of 325s on the rear and go with squared 305s. I'm wondering which wheels you ran the Michelins and Hoosiers on....and was each set staggered 11/11.5?

Also, on another note, I'm curious to hear your impressions on hood flutter and if you think there is a need to address it?

Yes, I ran staggered 11/11.5.

Hood flutter was noticeable, but not excessive. I don't plan to address it....

 

[Black Boss]

Nick was that R7 to R7 on both cars? Also interested to know if you run the 2's on track and if so how they held up.

@VoodooBOSS @fuhrius Sorry for the delay on tire info. Here's a shot of the front L & R PSC2's after 1 day (about 2.5 hours) of track time running 1.75* camber:

 

[VoodooBoss]

Wow. I suspect you drive more aggressively than me but those are expensive tires to burn through in one day. @Moto

How did the PSC2's compare to the R7's in both performance and wear?

 

[moto]

I see! What about tire pressures-hot? To the wear bars--does it look about half way used?

 

[Black Boss]

Hot pressures were 39-40*. I think they are less than half used, and the rears are probably only 20% used. Unfortunately I have no comparative data on the North course at VIR, but based on Brake wear day 1 to day 2 (on the full course) I'd say the North course is tougher on consumables. Wear and grip comparisons to the Hoosiers aren't really valid given the different course configurations, and that I increased camber to 2* based on the PSC2 wear pattern The most noticeable difference was reduction in understeer, some of which is obviously running square, some may have been camber related.

Subjectively (understeer aside) the PSC2's felt really grippy.

 

[Black Boss]

@cloud9 More Tire info re Hoosier 315 fitment. All these were on the stock GT350R wheels (11” Front, 11.5” Rear).

First I did a static test on the lift.

Fronts cleared the strut by 8mm versus 12mm for the OE PSC2 305’s. Laying a straight edge on the tire bead and compressing it to the sidewall there was zero clearance to the Fender on the Left and marginal clearance on the right, versus 6mm and 8mm of clearance with the OE tires. Also the Hoosiers have vertical sidewalls, where the PSC2’s taper a lot (see photo of rears below). Ran the steering full lock to lock with no issues.

Rear clearance on the inside is not an issue, however the tires poke by about 12mm, and this is compounded by the vertical sidewall construction.

Hoosiers:



Note the significant taper on the PSC2's:



I then applied painters tape to the inside and outside fender lip and mounted a camera to check dynamic clearance. First run was in damp-drying conditions, and ideal for a modest pace just kissing the curbs to check wheel motion. I checked the rears first as I was most concerned about these. Here's the video (with a close encounter between the Red Works Team Mini Cooper S and a Lotus at the 2:20 mark):

https://www.youtube.com/watch?v=6APS-cEk-Hw&feature=youtu.be

Following this I increased the pace for the next couple of sessions and monitored the painters tape -- no contact, but with extended wheel travel it must be close....

Next here's a video of the fronts with 2* of camber (sorry no spins!):

https://www.youtube.com/watch?v=TocXtJDDafw&feature=youtu.be

Good news -- wheel travel increases camber (great for clearance, grip and tire wear)...

Again, with increased pace and aggressive use of curbs later in the day there was no evidence of contact on the tape.

Not sure if this will be valid for GT350 suspension, but I'd be surprised if it's not as the front's appear to clear, and the only difference at the back is sway bar link length.....

 

[cloud9]

That's great news @Black Boss! I was really hoping the 315s fit. Dropping to a 295 up front would probably push like a pig and 295 square makes no sense as you'd give up so much contact patch. It sounds (and looks) like we need much more camber. I wonder if the Vorshlag plates could get us up in the mid to high 2* range. Hoosier recommends at least -2.5* iirc.

 

[fuhrius]

Look forward to hearing your feedback -- hope the weather cooperates. I'd love to run LS again

Without increased camber I'd expect even more understeer in addition to tire wear -- let us know......

good news / bad news - mostly bad. I was sidelined by some technical difficulty so I'm at a keyboard instead of a driver's meeting at the moment. the good news is I'm not going to tear up a set of 2's today with my paltry -1*ish of camber.

 

[8250RPM]

What do you think about a 305/30 square set up on R front and rear springs with adjustable sway bar links running 2+ degrees of camber on psc2 tires


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[CSL]

Subjectively (understeer aside) the PSC2's felt really grippy.

Would you say, subjectively, the PSC2 grippiness was comparable to an NT01?

 

[Black Boss]

OK, let me preface all these comments by saying that it's risky to draw firm conclusions from 1 day on each set of tires (PSC2's on day 1, Hoosier R7's on day 2) at one track. At best these are preliminary observations, in decreasing order of confidence:

Would you say, subjectively, the PSC2 grippiness was comparable to an NT01?

I'm confident that the PSC2's are grippier than the NT01's: the gap between Hoos and NT01 on the Boss was more noticeable than PSC2 to Hoosier on the GT350R

What do you think about a 305/30 square set up on R front and rear springs with adjustable sway bar links running 2+ degrees of camber on psc2 tires

Sent from my iPhone using Tapatalk

Based on 1 day, I liked the square setup better, but it's down to personal preference -- I like to get the car as nuetral as possible, others may like the inherent understeer in the stock set-up. 315/30 sqaure should also be an option if you have enough camber up front.....

That's great news @Black Boss! I was really hoping the 315s fit. Dropping to a 295 up front would probably push like a pig and 295 square makes no sense as you'd give up so much contact patch. It sounds (and looks) like we need much more camber. I wonder if the Vorshlag plates could get us up in the mid to high 2* range. Hoosier recommends at least -2.5* iirc.

Agree, the other options aren't attractive. Based on one day the R7 tire wear was pretty even with 2* of camber, and not too dissimilar to the wear pattern I was getting with the Boss at 3*. It was clear from the dynamic tire clearance video that camber increases with wheel travel. Here's a shot of the R7's:



Of course it would be great to have the option of more camber, but I thought I read somewhere that the Vorshlag plates weren't yet available for the stock 350 springs?

 

[cloud9]

Correct they are not available yet. Based on your wear pattern combined with your observations on the increasing camber with dynamic wheel travel, I will probably go ahead and install the MM plates at max camber. Can you remind me where you set rear camber and whether there's more available?

 

[Black Boss]

Rear Camber was 1.2* from the factory, very close to the R Track spec of 1.25* so I didn't change it. Spec for 350 is 1.00*

Rear tire wear looked even, but we'll see what happens when pushing harder. Of all the alignment settings, rear camber is the most difficult to adjust -- the bolts are well buried.

Also my Rear Toe was 3/32" In. Both the 350 and R Track specs are 0.30* -- which by my math is just about 1/8" -- I didn't alter mine, and didn't experience any instability under braking. Anyone @ArizonaBOSS @VoodooBOSS @fuhrius @Moto @voodoo child21 have any insight on rear toe -- this new fangled IRS is new to me ;D

** Edited to correct rear toe spec

 

[VoodooBoss]

I think the difference in the factory recommended camber settings is more tire than suspension dependant. Regardless they aren't going to be relevant for many of you.