Potential issues for hot upcoming track day?

clintfocus

im not specifically just talking about 370 VQ37 motors, VQ's in general from the early 35DE's, the 35HR's and the 37s have notoriously weak rod bearings when it comes to strength at high oil temps on track. 250 is like "you're about to spin a rod bearing if you keep at it" even if your oil is up to spec to survive at and past 250, the rod bearing's construction is not

from my testing, ive gotten rear diff temp to about 200 degrees give or take after 4-5 hot laps at buttonwillow raceway park in Socal during 85-90 degree weather,(300 is diff and or diff bearing kill zone) but this is also with my clutch type LSD, which can produce more heat then the stock Viscous LSD. But at the same time the stock VLSD is more prone to failure under heat at a lower temp then mechanical gear type or clutch type LSDs. general rule of thumb to keep diff from getting pissed, is keep you run session hard laps under 15 mins in 90+ degree heat, and under 20 mins in sub 80 degree weather

threeseventy

If you're getting LTH the day before I really hope you are having the UpRev retuned right after so you don't go super lean with all that flow and detonate like crazy. Adding a few gallons of 100 octane helps at high temps and it wouldn't hurt to have a 95 octane tune done (replace valet?) and run that mixture on track.

Definitely insulate the clutch line. Oil and diff fluid changes before and after track.

RN SHARK

Still on stock rear diff (on wish list!), no diff cooler either.

I was wondering about this and that is why I added this info in my initial post. I'm driving up to LA from San Diego and thought I could do a couple things in one trip. That is, go to Fast Intentions and have Tony, the exhaust master, deal with the demon bolt and install the headers, then drive across town to sleep at hotel and enjoy a track day in the morning. I was planning on doing another UpRev tune back in San Diego after the track day. I know not ideal, but will that be detrimental?
As far as octane goes, Auto Club Speedway and CA is very strict with selling it. I know that at the track it can only go into full race set-up fuel systems. They wouldn't sell it to me. Would a one-time octane booster additive help? I'm usually against those silly additives tho.
Again, thanks guys for all your help with these questions. This online community is great!

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'09 6sp/Z1/PowerTrix/SPL/Swift/SRP/Whiteline/F.I.LTH&CBE/UpRev by Seb/CJM/Stillen/Ings+1/RJM/TrackSpec/Sparco/Motul/Wavetrac/Coolerworx/Verus/CraftSquare
'14 SRT Grand Cherokee; '08 TL Type-S

threeseventy

Sebastian at SpecialtyZ does the best LA area tunes, and he's local to FI. He can pop a $35 SS clutch line in (you provide) insulate, and dyno-adjust your tune if there's enough time left in the day. There are various gas stations between the valley and the IE where you can get 100 octane. It's not leaded 110 race gas so it's not restricted. I always buy some 100 when at WSIR or BRP but haven't done ACS (I'm allergic to walls) so IDK about their policy on hi-octane unleaded..

I'll repeat what I said about fresh oil and fluids before and after. Seb will back me up.

cossie1600

Earlier VQ also weren't designed to rev to 7500RPM. Once again, how many 370's engine died from rod bearings failure?

Why would you tune for 100 octane for the track given the fuel starvation issue of the 370. You better hope you have a gas pump at the track.

clintfocus

the DE VQs didnt rev to 7500 stock, HR's did though, and HRs have the same rod bearing specs/size at VQ37s. the DE VQ's have a similar contruction but i believe slightly different shape. But if you dont believe me and feel 250+ oil temps is ok for your engine on track, then go right ahead. i honestly dont know, i havent gone around and counted blown from oiling issue 370z's, im just stating that it is a fact, VQ's have rod bearings on the soft side of metal compound making them eager to fail and spin at oil temps past 250.

also, he's not saying tune for 100, he's saying mix some 100 with your 91 to bring your effetive octane rating up higher then whatever octane you are tuned for, since track conditions always run harsher and hotter then any dyno can replicate. its cheap insurance against possible detonation. and your power will stay more consistant through out the day

threeseventy

Mine did. Yours could. More would if this place wasn't a haven for hardparkers.

[QUOTE=Why would you tune for 100 octane for the track given the fuel starvation issue of the 370. You better hope you have a gas pump at the track.[/QUOTE]

I said tune for 95. At least add some 100. There is 91 and 100 at the pump at all of our tracks. Helps a lot with these hot-running motherf*cking VQ's that we love.

clintfocus

my bad steve, but my input still stands.

ALWAYS run higher effective octane on track then what you are tuned for no matter the weather (unless its raining)