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This particular event has an instructor clinic on Fri and Sat, Hyperdrive laps on Sat, regular 4 DE groups, separate group for TT and two racing groups (Thunder and Lightning). Normal turnout is well north of 250 participants. Then there is hyperfest, which is also open to the public and that's usually double that with additional drifting and burnout competitions and all kinds of side attractions. I've been told NASA is currently not restricting number of participants, and while I'm sure it's lower than average, I still decided to skip this event and play it safe for now.
Wow. That sounds terribly packed! Good call on skipping. With that amount of activity you'd have a hard time getting a clean lap! I guess it does help in building passing skills. So, with that many run groups, how many sessions do you end up getting in a common day? And what is the cost?
Out here it ranges, but typically 5x 20 minute sessions. Some groups (like HOD and Turn2) are able to run 7 sessions across 3 groups, but that's an outlier, and expensive at ~$350/day. SCCA 'track nights' is another oddball in that it only provides 3 sessions, but it's lower cost at ~$140/evening. They lose session count by including timeslots for parade laps and 'race car' session.
Thanks for the link, that is super helpful to see how it's run. I see what you mean - they've packed in a ton of activity! It's funny though, the typical user cost is is ~$50/session in this format, and in our more expensive formats that run $350 for 7 sessions! So value is about the same, there are just more participants outt east. I wonder if it's just a population thing. More people in the east coast than west coast, and cost to run an event (track rental, emergency, turn marshals) are about comparable. Thanks for the insight. If you ever head out west, send me a PM!
Just came back from a day at Summit main with HOD. It was a good test day, their open passing group had 4 cars in it, so basically I had the track to myself all day. It was mostly overcast with temps in the high 70s and low 80s, so pretty much perfect driving weather. My takeaways:
The brand new Akebono brake kit feels great, but I did find the pass front caliper leaking fluid. Upon inspection it was actually leaking from where the two halves of the caliper meet. After tightening all the caliper body bolts the leak has stopped, but I'm still gonna contact CZP, obviously this caliper was not torqued down properly before powder coating. This should not happen.
Alignment felt good, but the steering wheel is just a tiny bit off. I guess I didn't set it right. I might have to invest in a string alignment setup so I can redo this myself as necessary.
I'm still not happy with the amount of rear grip and how easily the rear slides out under power. It's keeping me from powering out of turns as quickly as I'd like to. I think I'm gonna contact Fortune Auto and get lower rate rear springs. Current 10k springs are too stiff for now, I think going down to 7k will give me the rear grip I need. Once I get aero figured out I might swap back.
Otherwise car ran great all day, the oil and coolant temps stayed around 190 degrees even in the afternoon as outside temps got to about 85.
One more thing that I can't figure out. I'm getting tons of rubber buildup on the inside half of the tires. This didn't happen in my old car running similar slicks. Not sure if this is a camber issue, tire pressure/temp issue (36 psi hot) or something else altogether. After 10 laps or so there is so much buildup the car feels like I'm driving on gravel. Any thoughts on what could be causing this?
That sucks about the caliper leakage, and really unacceptable. Coz at CZP is a good guy, I'm sure he'll take care of your if you explain the situation calmly.
Really I'm wrting about your temperatures...how the hell do you stay at 190??? These cars typically run warmer than average. You know your car well and are running slicks, so you're definitely pushing it. After a20 minute session my differential is at 250F, motor oil at 240F, and coolant at 230F. This is at a 75-80F ambient. I have a massive diff cooler with 2x 4" SPAL fans, a 19 row oil cooler, and mishimoto radiator with higher pressure cap. WTF. What are your cooling mods? Are you heavy footed or light? I don't get it!
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WRT your rubber buildup question, I've had this hit and miss, noticing it on some tracks more than others and especially when it's warmer. I'm in the pNW< so not many 'hot' days, but I do notice buildup more in the summer time. Try to do a session with minimal trailbraking or hard power while still having a lot of steering angle at exit. Basically try to do a motorcycle line to 'diamond' all the corners, and see if it reduces. If it does then you know your scrubbing a bit and can alter your line/inputs a bit to maximize tire wear. Another big cause of build up is cold wheels on a hot track. Basically if the track has high turnover (lots of groups/sessions) with minimal sweeping then it'll build up marbles on the off-line. If they are fresh then they are still warm and sticky. Especially if it's hot outside. Then when you come in fresh and cool from the paddock, or go offline during a pass, then your cooler wheels will attach to the rubber easily. Here's an article that goes into more detail. https://buildingspeed.org/2016/08/05...d-lose-rubber/
Please help me with my cooling issue! I want temps like yours!
Talked to CPZ, they are saying they'll contact Powerstop that supplies them the calipers, but they haven't "had a ton of success". Not sure what to make of that, I'll keep at it.
Re: temps, I don't have a diff temp gauge, so I can't say anything about that. The coolant temp sensor is in the upper hose by the thermostat so it should be accurate, the oil temp sensor is right on the external cooler adapter plate. I do have a 3 row radiator with high pressure cap and I run a 30 row oil cooler but no extra fans. In my experience fans are good for being stuck in traffic but tend to restrict airflow at high speeds. I also don't have an a/c condenser blocking the radiator and no heater core. The engine is 100% stock, but I have no cats or any real mufflers to speak of, so it's more free flowing and likely runs cooler as a result. One more thing, I think the front lip does help push more air into the radiator area but that should be negligible.
I guess my question is not really why I get buildup, it's why I get buildup only on the inside 1/2 of the tires. As far as the track conditions, I noticed the buildup only after about 5 laps and getting worse from there, but also I was testing the suspension so I was hitting every curb deep on purpose to see how the car would react and since there were only 4 cars in my group it's possible there was a lot of rubber buildup on the curbs from student groups that were much larger, but they don't tend to use the curbs very much. But going back to the question of why only the inside of the tires. You're saying the cooler wheels will pick up rubber, but here it seems the hotter area of the tire is getting more buildup. I mean, I have 4 deg of camber in the front and 2.5 deg in the rear, I can't image the inside of the tires are cooler than the outside?
I've been thinking about the camber, and while I'm not seeing any weird tire wear right now I might try to reduce it a bit, maybe go to 3,5 deg front and 2 deg rear, see if the buildup is more uniform across the tire. I'm wondering if with super stiff suspension on the car right now, as flat as it is thru the corner big camber might not be necessary.
I bought my Stoptech front/rear BBK kit from CZP and also had issues WRT drop shipping. My issue wasn't quality though, it was simply the wrong car (Z31 vs Z32). But they fixed it and it was all good. Be firm (but don't be a dick) and I'm sure it'll work out for you.
For the cooling topic, I just don't understand. We're not THAT much different. My water sensor is in top hose as well, but my oil sender is on the pan , or really on the Z1 pan extension. Both yours and mine should be comparable oil temp, unless you're measuring the line going into the motor from (IE after the cooler). Not really sure how those sandwhich plates route the fluid, so I can't tell which you're measuring...My motor is also stock, but I still have cats, so going to be a bit warmer. Your oil cooler is only 20% more rows than mine, so again I'll be a little warmer, but shouldn't be that bad. I still have the OEM fan assembly and heater core. Not sure hose those affect flow. I think you're right the fan assembly is a restriction at higher speeds. I also have the AC condesor removed, but have basically zero rad ducting, so it's not great flow. On the diff cooler it's a requirement to have fans since the air back there is so turbulent and difficult to route. Can you share details on your radiator? This is the one I have, and am not super impressed atm...https://www.z1motorsports.com/coolin...or-p-3544.html
I wish I had better info to share for your tire rubber buildup. My guess is that it's just marbles being spit up and sticking. That aligns well with your hypothesis that other groups weren't cleaning the area near curbs much. Maybe share a picture and I can tell you if it's significantly different then what I develop on my ID.
For your camber, 3.5 front sounds like a good target. But for the rear only go down toe 2.5, as you want the f/r difference to be 1.0 max. I'm doing an alignment this evening in prep for event on Thursday and will be setting to 3.5/2.5. That was my setup for a long time but reduced it to 3.0/2.0 hoping to be more street freindly during the winter months. It was a bad idea, I didn't drive the car enough to make it worth it and enevitably wore out my outer shoulders on current rubber
That's a good point and you can definitely install the oil temp sensor before or after the cooler (there are 2 ports in the plate) but I spent an excessive amount of time during installation ensuring i was installing it before the cooler, so I'm like 95% sure it's before, but there is always that 5% chance I'm just an idiot :P
I believe my radiator is a GPlus, which is a domestic copy of the Mishimoto at like half the price, has same specs and design as far as I could tell.
Thanks for the info, I'll try to reduce the front to 3.5 and keep the rear at 2.5 for now. As I said, the tire wear seem to be fairly good, so it's more of an inconvenience than a real problem right now.
Got the caliper and the springs swapped today. Comparison of the 10k spring vs 7k spring, can definitely tell a difference, the rear of the car now has some give to it, should give me a bit more grip
I also took pics of the rubber buildup on the tires. So here's in order pass front, driver front and driver rear. The pass rear was the only tire with no buildup. The buildup is always on the inside part of the tire. BTW, Summit Main is clockwise. I'd really like to hear thoughts on what's causing this buildup in a narrow band on the tires? Is it too much camber? I did just changed the front camber from 4 degrees down to 3.5 so maybe that'll help...
No, as I wrote before, it starts to build up about 5 laps in and gets worse with each lap. The fact that there is buildup is fairly normal, I'm not worried about that, it's the range of the buildup that is the question. The buildup should be uniform across the tire, but here it's in a narrow band.
That's easy, it's the inside back wheel on this particular track, as such it's the wheel with least amount of weight and pressure on it and does the lowest amount of work in right-hand turns, which is most of the turns at Summit Main, so is much less likely to overheat.
I have a ton of laps on Main...and even with cool down off line I don't think I have ever gotten any appreciable pickup. Hoosier A's tend to pick up everything in sight, too...
That's easy, it's the inside back wheel on this particular track, as such it's the wheel with least amount of weight and pressure on it and does the lowest amount of work in right-hand turns, which is most of the turns at Summit Main, so is much less likely to overheat.
So there are two likely factors at work here, hot tyres and debris. Check tyre temps and review the lines you take, obviously debris pickup is more likely if you use lines that are different to the usual.
Suspension and alignments may cause a difference as to where the pickup occurs on particular tyres but they seem unlikely to be the main cause. I guess that it could be something to do with spring/damper rates but that's too far for me.
Yeah, the more I read about it the more I think it's mostly tire temp related. I need to reduce the hot pressures a couple psi and see if this goes away.
06-25-2020 | 09:11 AM
