RTR smackdown!

[blkwrxwag]

I ran the ZIIs this weekend - certainly no magic bullet on my car, and in some ways, worse than the ZI. My car normally stable STR car became very loose and hard to drive at the limit. I think the Z11 works better on cars with softer suspension than mine.

[Dezoris]

Originally Posted by dwx

RTR is stock with street tires, perhaps you meant STX? The cars referenced just have front sway bars, an alignment, and better street tires.

Sorry I am brain dead. Tks

[apexaddict]

Originally Posted by race2win

I think this is a very key point to the results at that event. Other than the Tire Rack's informal test months ago, there is really no informative data that says how much better the ZII is over the Z1 in an autocross environment. I think it's safe to say that the ZIIs are at least a little faster on the watch compared to the Z1, so I'm willing to bet both of those cars/drivers could have gone even faster on the new tires.

Last weekend I was also able to run times that would have won STX in Des' car against trophy winners from Lincoln last year. But it was the same scenario, we were on the ZIIs & the STX guys were on last year's tires so it's hard to say if it really meant anything.

To add another data point, Dennis Sparks (an STX-er from the southeast) did a test and tune yesterday, and he determined no real discernible time difference between 100-run Z1s from last season, and some freshly-scrubbed Z2s.

He posted this on Facebook:

As promised the results of my Direzza Z1 vs. ZII testing from this weekend. ALSCCA hosted a two day test and tune this weekend at Oak Mountain Amphitheater in Birmingham.

Saturday was a conventional test and tune. It was sunny and temperatures were in the low 40s. We put the ZIIs on the car and Jordan Towns and I each made 6 runs while adjusting the set-up. They were fast pretty much out of the box and we were both running times within 0.2 sec of the top pax driver by our 3rd runs.

The Z1s for the test were left over from last autumn. They purchased in Oct before the Tri-State National Tour. They were used for 5 events and one track day, about 100 runs total. Wear is just above half.

Sunday was limited entry test and tune with 6 hours of autox and almost no wait between runs. Weather was sunny and temps were in the high 40s early up to the mid 50s by the end of the day. The Oak Mountain Amphitheater lot is paved in moderate grip asphalt but tends to be a little sandy so courses there continue to improve throughout the day as the sand is swept from the line. Clay McCool set up one of the best test and tune courses I’ve run in a while. It featured a seven cone slalom, high speed left hand sweeper, lower speed left and right sweepers, followed by high speed offsets through to the finish.

We started the day on the ZIIs. After 5 runs times were in the 35.6 – 35.8 range. We then switched to the Z1s. Times picked up right where we had left off with the ZIIs and ranged from 35.3 – 35.6. We then broke for lunch. After lunch we continued with the Z1s. Times were steady at this point ranging between 35.3 – 35.6 for both Jordan and I. We made a final swap back to the ZIIs to close the day out. My first run was a 35.2 and then we both had a string of runs between 35.3-35.6.

So for this test there was no discernible time difference between the two tires. They do feel different though. The ZIIs have a crisper turn-in. The Z1s feel sloppy in comparison. In the slalom there was a noticeable difference in the required inputs; you needed to anticipate the turn in more with the Z1s. The ZIIs are also less forgiving to slip angle than the Z1s. Overdriving the Zll results in a crisp breakaway that requires immediate correction. The Z1s, in comparison, kind of wallow at the limit but are easier to maintain at or near peak slip angles. Jordan and I both preferred the ZIIs in the slalom. It was much easier to hit the marks and rotate the car around the pylons. Different story though in sweepers, it was harder on the ZIIs to enter at peak speed without breaking loose and going wide. The offsets were a wash: the ZIIs were more exciting but less forgiving if you got late, whereas the Z1s didn’t feel as fast managed to get you through them with more confidence and less drama.

Tire pressures for the two tires were very similar and worked over a good range of pressures. They functioned well between 28-33 psi both front and rear.

So whether or not the Z2s were actually that important of a factor in this case can be debatable. What I'm taking away here, though, is that the softer and more forgiving RTR cars appear to have more to gain from the stiffer, edgier Z2 compared to the STX cars. But grain of salt and all that.

Of course, the dark horse is still the Rival, but I'm not convinced yet that it's much more than a glorified RS3 until some real testing is done. And it will be interesting to see if that changes RTR and STX even further.

[Kido1986]

My Whiteline bar just feel too big for my liking. To make the car neautral, I'm staggering an additional 4.5psi hot in the rear over the front (35.5F,40R) on 215 RS3s. Strano bar is in, but not on yet. I'm hopefully putting the Koni shocks on this week so I'll do the bar then. First event is this Sunday so I'm sure I'll have a struggle on my hands to find the balance in the Konis.

And I even managed to beat the STX class at this past event, well prepped RX8 just couldnt keep up.

I've let some really good drivers take a round in the car and enjoy it so far. Hoping the Konis dont make the car feel so different I can't drive well at this weekend's event, it's my favorite autocross venue in the state

[Simmons]

Originally Posted by blkwrxwag

I ran the ZIIs this weekend - certainly no magic bullet on my car, and in some ways, worse than the ZI. My car normally stable STR car became very loose and hard to drive at the limit. I think the Z11 works better on cars with softer suspension than mine.

Did you try to make changes for it?

Simmons

[blkwrxwag]

Originally Posted by Simmons

Did you try to make changes for it?

Simmons

Yes indeed. We did dial some of the looseness out, but that just made it sketchy at both ends. Softened the shocks as much as possible and played with rake, but it was just tough to drive in the sweepers.

Maybe softer springs would help, or different shocks!

[Simmons]

Originally Posted by blkwrxwag

Yes indeed. We did dial some of the looseness out, but that just made it sketchy at both ends. Softened the shocks as much as possible and played with rake, but it was just tough to drive in the sweepers.

Maybe softer springs would help, or different shocks!

What about rear toe?

Did you have other tires with you to compare on the same day?

Thanks,

Simmons

[blkwrxwag]

I didn't play with rear toe, and no other tires to compare. Also, until I have a few more heat cycles on them, I'm not willing to do much more than I already did. I might stiffen the front bar as well, if things don't improve.

I haven't changed the setup of my car this much in two years - it was enough of a traumatic experience as it was!

My point was - no magic bullet found!

[blkwrxwag]

Video of said twitchiness....

[Simmons]

Originally Posted by blkwrxwag

Video of said twitchiness....

Looks like mid corner to exit?

What kind of chicago box was that? way too easy :happy0180:

Simmons

[zo7vette]

This was my first event in the FRS. Car felt great, really fun to drive. I messed up my car, I didn't take enough care and time installing the front sway bar and crash bolts. My endlink nuts were almost completely off when we checked the car yesterday. Most important mistake, I didn't take care watching the crash bolts being tightened by my technician, they went back towards positive while tightening, giving me .3 positive on the left and .3 negative on the right. These are the things that happen when you rush to get ready, my fault completely.

I am very happy with how the car felt, good balance, fun to drive. New Z2's were excellent. My driving was a bit sloppy until my final run that got me down to the 62.5. I feel with the better set-up and more focus I could have been in the upper 61's, but still way back of Buetzer. Keep in mind, Ryan only ran 3 runs in the ZOK, on the Z1's, he had such a lead he jumped into Des's car for his final run, and laid down a nice 62.3.

I talked to Ryan after he drove both cars, he thinks the car should have been classed in DS, and still believes that. It stands no chance against the ZOK or MSR. I bought the car knowing it had no chance in CS, I have run an MSR nationally, and this car just can't keep up. 1 of my goals for the first part of this season is to collect data to start the campaign to have it moved to DS, I feel D is the best fit versus moving the ZOK and MSR up to BS.

Jeff Cawthorne
2013 Hot Lava FRS CS/RTR

[simpleisbest]

Originally Posted by des

Lugod drove Sean's FRS with the big bar as well and was a bit slower; he said it was pushy. The tires were at 40/40, and he suggested going even higher in the back.

So it looks like Mr. Strano's bar hits the sweet spot. Cawthorne picked up some time fun runs but had an alignment issue -- he has bolts but didn't really gain any camber, which could not have helped with such a sweeper intensive course.

Nice report Des! Wish I drove better, I left a ton of time out there on some of those long sweepers from just not pushing it enough.

My FSB is the big Hotchkis bar on the soft setting (w/Hotchkis endlinks)

While I am not totally sold on the 40/40psi (originally intended to use 40psi squared as a start point to tune from, but left it there as they felt so surprisingly good) pressures and will be looking to bring them down some at the next event. I think I am about 3-5psi away from finding a nice sweet spot, though.

While, I am looking to try the Strano bar eventually, I think the Hotchkis bar is decent for now. I don't think the car is not so much "pushy", as "not loose". More toward the pushy end of feeling "balanced". (never had the complaints of plowing like others on this forum claim to have with the Hotchkis) The car is very easy to drive now and confidence inspiring, but I will look to zero out the rear toe to see how it changes things.

If you pick up the Strano bar before I do though, I would love to hear how it compares!!

Sean F

[Kido1986]

I could only get the push to stop with the rear pressure jacked up. Looking forward to the Strano bar. Just waiting to do that at the same time as the Konis (hoping they can get on before this weekend's event).

The Hotchkis turn in was awesome but midcorner, I just couldn't rotate very well at all until I hit that large different in rear psi. This was on pavement. On concrete... dear god the car was just awful.

[xwd]

Originally Posted by Kido1986

I could only get the push to stop with the rear pressure jacked up. Looking forward to the Strano bar. Just waiting to do that at the same time as the Konis (hoping they can get on before this weekend's event).

The Hotchkis turn in was awesome but midcorner, I just couldn't rotate very well at all until I hit that large different in rear psi. This was on pavement. On concrete... dear god the car was just awful.

So were you using a Whiteline bar or Hotchkis bar? I know the Hotchkis one is a little large. I have both the 20/21mm whiteline and the strano bar, from my butt it feels like the Strano is in between the two settings on that bar.