SCCA Solo D Street discussion

[Alexioooo]

Hi all,

Question about recommendations for good auto-x tires that would keep me in DS.
My good friend runs Direzza ZII's on his Mini and swears by them.
I don't really drive the BRZ in the winter months much at all, so I'm okay with soft(er) tires but I would like to be able to get 2 or hopefully 3 summers out of them with scattered autox events. (I know that may be a stretch)

Sorry about the lack of much info to work with but I'm just looking for feedback on what some of you guys run and what you think about the tires so I can try and shave a few seconds at some events.

[dvalue]

Originally Posted by blkwrxwag

Quick question for those with experience of Konis.

I installed them yesterday and was surprised to find that my car did not lower itself by at least half an inch due to the lower gas pressure. In fact, the car is a bit higher in the rear.

Could this be because the stock shocks (with 34,000 miles on them) are already a low pressure shock, or am I a complete buffoon?

On my NC2 MX5, the Konis lowered the car significantly.

The good news is the car rides great with no clunks and squeaks. I double checked the installation about 10 times to make sure everything was seated correctly.

You may have the perch upside down. I made the same mistake with mine.

[blkwrxwag]

Definitely not that. Installation confirmed as correct. In the rear, I may try loosening the control arm bolts and tightening them again with the car on the ground.

[dutchman1]

Originally Posted by blkwrxwag

Definitely not that. Installation confirmed as correct. In the rear, I may try loosening the control arm bolts and tightening them again with the car on the ground.

When I installed mine I loosened every bolt going through a bushing on the corner of the car I was working on, then jacked the hub up until the axle shaft was level. I torqued all the suspension bolts with the suspension in that position.

When I went and got my alignment later that week, I had it done by the guy that does a good chunk of the local autocross alignments in the area. He said my car had by far the most symmetrical camber of any frs/brz/86 he's worked on, so I did something right.

Might wanna try that.

[blkwrxwag]

I definitely did that in the front. I'm going to do the rear again to make sure there. Thanks.

[M0nk3y]

Originally Posted by blkwrxwag

I definitely did that in the front. I'm going to do the rear again to make sure there. Thanks.

Max, while doing rideheights I've observed these cars take a long time to settle. Give it a day, drive it around and see if there is any difference


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[blkwrxwag]

Thanks Kyle. Will do.

[strat61caster]

Originally Posted by Alexioooo

Hi all,

Question about recommendations for good auto-x tires that would keep me in DS.
My good friend runs Direzza ZII's on his Mini and swears by them.
I don't really drive the BRZ in the winter months much at all, so I'm okay with soft(er) tires but I would like to be able to get 2 or hopefully 3 summers out of them with scattered autox events. (I know that may be a stretch)

Sorry about the lack of much info to work with but I'm just looking for feedback on what some of you guys run and what you think about the tires so I can try and shave a few seconds at some events.

Bridgestone RE71R and BFGoodrich Rival S are the top fast tires, depending on how many miles you expect they could be perfect. And we're talking like 5k miles here, maybe 10k max if you're an easy driver and don't AutoX frequently. Nexen has a tire people are playing with, but you probably don't want an unknown quantity, Kumho and Federal also have tires that do well but not as well as Bridgestone or BFG.

I had Z2ss when they first came out, decent tire, stretched them to 20k miles and did a few track days and a season of AutoX, they definitely don't have the grip of the other two but the tread will last longer. Similar story for the other 200TW tires aimed more at track use like Hankook RS4, BFG Rival, RE11, and whatever else I've forgotten.

If you want to be quick dive into the top tires, worst case you replace them earlier than planned and decide then if it's worth having maximum grip. If you're still figuring stuff out the z2 or similar might be a good tire to learn on and sharpen your driving skills before jumping up a grip level, but you may hit a point where you want the grip and are just dying on non-competitive rubber waiting to get rid of them (but a second set of oe wheels for this car are cheap). Or hey, maybe your local scene isn't that competitive and you can win on Pilot Super Sports and DD them for 30k miles at the same time, idk.

[Alexioooo]

Originally Posted by strat61caster

Bridgestone RE71R and BFGoodrich Rival S are the top fast tires, depending on how many miles you expect they could be perfect. And we're talking like 5k miles here, maybe 10k max if you're an easy driver and don't AutoX frequently. Nexen has a tire people are playing with, but you probably don't want an unknown quantity, Kumho and Federal also have tires that do well but not as well as Bridgestone or BFG.

I had Z2ss when they first came out, decent tire, stretched them to 20k miles and did a few track days and a season of AutoX, they definitely don't have the grip of the other two but the tread will last longer. Similar story for the other 200TW tires aimed more at track use like Hankook RS4, BFG Rival, RE11, and whatever else I've forgotten.

If you want to be quick dive into the top tires, worst case you replace them earlier than planned and decide then if it's worth having maximum grip. If you're still figuring stuff out the z2 or similar might be a good tire to learn on and sharpen your driving skills before jumping up a grip level, but you may hit a point where you want the grip and are just dying on non-competitive rubber waiting to get rid of them (but a second set of oe wheels for this car are cheap). Or hey, maybe your local scene isn't that competitive and you can win on Pilot Super Sports and DD them for 30k miles at the same time, idk.

Thats some good insight, thanks. Considering up here I only do maybe 3 events a season, super grippy may not be necessary. Leaning more towards longer lasting tires. Seems like the top tires won't last as long as I'd like them to, but thats fine cause I expected that.
I mean I'm lucky that where I auto-x really isn't that competitive (though I do like competition) cause I've podium'd every time on the stock rubber, so a slightly better tire is what I'm looking for and if I can get them to last me somewhere around 20k miles, thats perfect. Think I may just go w/ the ZII's.

[Shark_Bait88]

I had ZII Star Specs on my car for a year. 3 track days, a handful of autocross events, and about ~12-15k miles on them, and they were around 45-50% tread life when I took them off. Great tire for the money. Won't set top times at autox, but will still do well enough to place you mid pack (and possibly trophy) depending on your driving and the competition. Excellent tire for track days, and they work really well in the wet for daily driving in the rain.

You may also look at the Falken RT615k+. It's my understanding that they're based on an older ZII tire and work very well for a more value performance tire. They'll run you about $60/tire less than the ZII*

[Locust]

Originally Posted by Shark_Bait88

I had ZII Star Specs on my car for a year. 3 track days, a handful of autocross events, and about ~12-15k miles on them, and they were around 45-50% tread life when I took them off. Great tire for the money. Won't set top times at autox, but will still do well enough to place you mid pack (and possibly trophy) depending on your driving and the competition. Excellent tire for track days, and they work really well in the wet for daily driving in the rain.

You may also look at the Falken RT615k+. It's my understanding that they're based on an older ZII tire and work very well for a more value performance tire. They'll run you about $60/tire less than the ZII*

I'm going to second the ZII Star Specs if you need an autocross tire that lasts a really long time. These things last forever but they're definitely a full tier below the RE71R and Rival 1.5S.

[Alexioooo]

Originally Posted by Locust

I'm going to second the ZII Star Specs if you need an autocross tire that lasts a really long time. These things last forever but they're definitely a full tier below the RE71R and Rival 1.5S.

Thanks Locust and Shark_Bait88 the ZII's are looking more and more appealing. But w/ those RT615K+ I can save about $200 for the set... might be the move to make and just hope for the best. If I dont like em I'll upgrade.They seem to have some good reviews. Plus I can put some SICK Falken stickers all over the car. JK.

[Shark_Bait88]

Originally Posted by Alexioooo

Thanks Locust and Shark_Bait88 the ZII's are looking more and more appealing. But w/ those RT615K+ I can save about $200 for the set... might be the move to make and just hope for the best. If I dont like em I'll upgrade.They seem to have some good reviews. Plus I can put some SICK Falken stickers all over the car. JK.

A track buddy of mine is running them on his BRZ this season and really liking them. I think they should do the trick for ya.

[blkwrxwag]

Originally Posted by blkwrxwag

Quick question for those with experience of Konis.

I installed them yesterday and was surprised to find that my car did not lower itself by at least half an inch due to the lower gas pressure. In fact, the car is a bit higher in the rear.

Could this be because the stock shocks (with 34,000 miles on them) are already a low pressure shock, or am I a complete buffoon?

On my NC2 MX5, the Konis lowered the car significantly.

The good news is the car rides great with no clunks and squeaks. I double checked the installation about 10 times to make sure everything was seated correctly.

Just to follow up on this, I talked Lee Grimes at Koni about this, and here is his explanation.


"That's exactly correct. There can be a minor height effect of going from Mono-Tube High Pressure Gas down to Twin Tube Low Pressure Gas and less of a change from Twin Tube Low Pressure Gas to Twin Tube Hydraulic (non-gas). There is also some interplay within that related to the piston rod diameters (gas pushing on a fat rod will lift more than a thin rod due to area/displacement) and also vehicle mass (lighter car effected more by same gas than heavier car). I think an inch difference is really extreme though so it is likely a generalization/exageration even if you went from high pressure to non-gas. There may have been otehr contributors as well.

The NC probably had MT HPG Bilsteins on it and you went to TT LPG or non-gas. The Twins use TT LPG from the factory and that is what the KONIs are as well. The spring perches are all exactly in the same location as required by SCCA rules and also making the stock or aftermarket springs set the same height as the OE dampers. SCCA does not actually measure ride heights but isntead measures parts so minor height changes based purely on gas differences have no legality issues if the perches and mounts are the same."


So there you have it, the Twins already have Low Pressure Gas twin tubes, so switching to the Konis will not decrease the ride height any.