wstar's Journal

wstar · 06-17-2014, 02:58 PM

Yeah, so someone asked on the "visitor messages" thingy here: Nissan 370Z Forum - Conversation Between 12nismo and wstar about whether the engine failure was pulley-related and whether I moved my crank pulley to my new block. The TL;DR answer to that is: I *think* the failure was unrelated to the pulley, but I also did *not* move the pulley over to the new block.

The long explanation, if the above is important to you and/or confusing:

Personally, I don't think the (Stillen, light/underdrive) pulley was a significant factor. My best guess is the flywheel probably started cracking a long time ago, adding some imbalance/wobble to the crankshaft and beginning to cause excess wear in the crank bearings, and then when the flywheel finally got bad enough (when the last bit cracked on that fateful Saturday), we had some major imbalance/wobble/whatever going on that really tore up the bearings, along with the flywheel striking the crankshaft position sensor, which is what caused the engine to go into limp mode at that point.

Even then I think the bearings were merely damaged at that point, but not seized/spun, initially. They didn't really come apart until test-fires and moving the car around around later, off-track (but that was inevitable at that point, they were shot one way or the other)... which brings us back to the Great Internet Pulley Debate (which rages forever on almost every car forum), where pulley-detractors tell us that lightweight pulleys without dampening rings on them will destroy crankshaft bearings over time.

To recap the basic internal/external balancing stuff, open the spoiler (or you can skip this as a TL;DR reduction if you get this part already):

( Click to show/hide )

Our engine is an internally-balanced one, meaning the pulley doesn't play a role in basic rotating-assembly balance issues on this car. It *does*, however, contain a rubber vibration-damping ring on the outer face of it. The core of the real debate here is whether the purpose of that vibration damping ring is purely for aesthetic NVH reduction, or whether it has a real dampening effect that partially reduces some mechanically-important crankshaft vibrations from combustion (and if so, how much longevity are you losing if you eliminate this? It could be 5%, it could be 95%!).

Anecdotally, I don't think it's much of a loss, if any, because the pulley kits from NST and Stillen (and others) have sold tons, and we're not hearing about massive lawsuits or even complaints about destroyed engines. It's most likely that the ring is mostly about NVH. Maybe it also reduces some mechanical vibration that matters, but maybe that's not very significant to begin with. For this sort of reasoning, I'm generally of the opinion that you're not risking any kind of large or short-term damage by properly installing a pulley kit on this engine. That and my engine made it through a considerable number of very abusive track miles on such a pulley (and even then, I don't think it was the cause).

However, I can't in good conscience say that without adding 3 important disclaimers/caveats:

My car is a 7AT, not a 6MT. Vibrational issues could be different on the two. I tend to suspect that, if there is any issue, 7AT's would fare better than 6MTs. This is because a 7AT has a torque convertor full of transmission fluid bolted to the flywheel at the rear of the engine. I suspect the torque convertor acts like a giant fluid damper on the rear of the engine (e.g. The Original Fluidampr ), offering far better vibration damping than any silly rubber ring on a pulley ever could.
Regardless of all the logical weaseling above, you can't escape a few basic facts: Vibration hurts engines. All engines vibrate. There's a small rubber ring on the stock pulley that may help with some unknown vibrations to some unknown degree. You're tossing that out for a <1% difference in the engine's performance capabilities at the end of the day. Maybe that's worth it, maybe it isn't. How much stress you're putting on the engine to begin with is a big factor. If I were building a 750rwhp turbo monster, I'd probably go in the *opposite* direction and install a heavier replacement pulley that does some serious damping to increase longevity. On an N/A street engine, I doubt you'll ever know the difference (in performance *or* longevity), making the upgrade pointless.
Jason (the mechanic who did the swap, and who I think has a trustworthy opinion about all car things) recommended against moving the pulley over to the new engine when moving all my other stuff over, because he thought it *could* have been a factor, and it's not worth the risk if it was. While, academically, I may believe it to not be a major contributing factor in the failure, I don't believe that strongly enough to tell him "No, put it on anyways", especially given that I could end up destroying this replacement block in a short period of time via something totally unrelated and coming right back to him with it, at which point he'd get to say "I told you so" about the crank pulley whether it was the issue or not, because that's only fair at that point. So he put my stock crank pulley on the new block, and that's what I'll be running for the foreseeable future (until I kill this engine in some new and imaginative way!).

theDreamer · 06-17-2014, 03:00 PM

12nismo is cobb in Houston.
He is getting his pulley put on this week so wanted to make sure your engine failure was not related.

wstar · 06-17-2014, 03:10 PM

Apparently he's already doing it. Unfortunately I don't have any easy answers for him, hence my huge diatribe above! Maybe an appropriate closing statement would be: if I could rewind time and start over, I'd still have put the same pulley on my (7AT-, NA-, track-) car back when I did.

12nismo · 06-17-2014, 04:01 PM

Just got the kit installed and I'm very happy with the results...as long as the motor holds up, lol.

VoBoy · 06-17-2014, 08:52 PM

so just curious, what's your preventative don't blow up the engine plan in the future? flywheel replacement every 1 to 2 years?

wstar · 06-19-2014, 06:30 PM

Well, I'll certainly at least pull the starter and access covers and take a look at it from time to time. I suspect there was a good amount of lead time between the first crack and the bad situation at the end, but "inspect the flywheel" was never really on my track prep checklist before

I've got my old block back at home now with an engine stand as well. I plan to get that one rebuilt stronger and then drop it back in the car at a later date. Once I get to see the extent of the damage I'll know how much basic work needs doing and whether the block needs to see an engine rebuild shop first (probably). Once the block is basically sane, I'll probably drop in a bunch of upgraded parts for durability (e.g. Nismo oil pump, GTM HD flex plate, custom water inlet/outlet stuff with good fittings and no stupid heater connections, etc). Depending on time contraints, budget, and craziness, I might go further and build it up into something awesomer (e.g. one or more of 4.0 stroker, lots of forged high quality internal bits, dry sump, custom race ECU, etc). Right now the budget picture is pretty bleak while I recover from replacing the engine in the first place, but that will turn around in a few months.

wstar · 06-19-2014, 06:39 PM

Also, I took the still-unused 265/645 Wets off of my extra 18x10 wheels and had the 285/645 slicks mounted. The rims *still* aren't well-protected, even though I'm sure 10 inches is a good width for these 285's. Part of the issue is probably that race tires don't have rim-protectors built into the rubber mold, and that these Forgestars have particularly thick rim edges. When stacking these on their sides, the metal of the wheels don't touch each other or the ground, but it's just by a hair's width. Set them down too hard and you can hear them click into each other. I think I just have to live with that for now, because otherwise this setup should work great for trying out these cheap slicks.

Assuming no other major issues get in the way (like my car blowing up and/or dying), I think my general plan at MSR-H this weekend is to spend most of the weekend on my existing RS3's, then maybe switch the slicks on for the 3rd or 4th session Sunday and scrub them in over a whole session slowly coming up to full speed. Then they'll sit for a week for that whole mfg-recommended rebonding process and I'll try them again at COTA the next weekend (with the remaining life on the RS3's as a backup option. I might even start out on the RS3's and then switch to the slicks later in the weekend instead, so that I'm super-comfy with the track/event before adding that new challenge back into the mix. All depends how things feel during the scrub-in session this weekend).

Pics, off the car sitting at 25psi cold pressure (I suspect I might need to start them even lower than that, still researching):

sig11 · 06-19-2014, 07:56 PM

You won't want to go back to the RS3s!

Mike · 06-20-2014, 11:14 AM

I shoot for 36 hot on them. Not quite the same grip as the A6s, but still a great tire.

wstar · 06-23-2014, 08:51 AM

Had a great weekend at MSR-H!

New engine seem to be running great! Only have a couple minor things to look into: oil temps looked a little higher than expected (240-ish but it was a very hot weekend), and upshifts were a little slow and clunky on Saturday (but gradually got better for some reason; could have been me subconsciously adjusting shift timing or lifting throttle. Could also be that the fluid level's a little off?). Car's already back on my mini-lift for basic maintenance. Going to swap out the engine oil (since this was the first fill for that engine since the salvage lot), check trans fluid level, replace front rotor rings (finally, and replace studs+lugs while I'm in there), bleed brake fluid, etc for the coming weekend at COTA.

I did my Red-group check ride for MSR-H (Driver's Edge does these per-track, so the one at TWS was separate from this) on the first Sunday session and that went great, so I got to spend half my weekend in Red. Kevin was my check-ride instructor; his line advice was amazing, but it will take a while for me to get out of my old habits and pick up speed from what he was saying

I did scrub in the Conti GT-O slicks in the final session Sunday. As usual, my fears were all in my head. There was no problem controlling that tire, and it felt amazing. We had about 8 hot laps that session. I spent the first 6 slowly edging my way up on laptime and trying not to put any big slip angle in them, then the final 2 laps I ran at my normal pace for the RS-3's and I could finally start to feel a little slip. You could tell the tires were nowhere near their limit at my RS-3 pace. At places (and speeds) where I'd feel unstable or fighting the car way out at the edge of acceptable traction in the RS-3, the Contis were just rock solid and predictable. There's clearly 2-3 seconds I could take off my laps here if I adjusted my pace up to the tire's limit with slicks like these. (Then again there's also clearly 1-2 seconds I could shave if I made some basic line fixes; who knows how much those two figures overlap).

Also, they look great on the car

--
Fastest lap for the weekend was 1:52.21 (second-to-last session of the weekend, still on the RS3's):

wstar · 06-23-2014, 09:31 PM

I went ahead and encoded the whole session that the fastlap above came from. Spent that whole session chasing down the same red Lotus (well, once he got back in front of me around the end of Lap 4). Lots of data to pick up from it on how and where he was faster than me. Mostly, it seems like he was doing better pushing out of the inner carousel wider and earlier on the throttle, and he was way more gutsy staying in the throttle before, during, and just after The Launch (the little hill):

Mike · 06-23-2014, 10:10 PM

240 is probably just normal in summer. I saw 230 at road atlanta weekend before last, and Russell from Z1 and Brian Kleemans Pirelli challenge car were around 260-70, but my stillen bumper probably helped me. this weekend at AMP which doesn't have long straight and is shorter, I was in the 230-240 range. It is summer!

wstar · 06-23-2014, 10:17 PM

Time for hood vents I guess

BGTV8 · 06-30-2014, 05:50 PM

Quote:

Originally Posted by wstar

Yeah, so someone asked on the "visitor messages" thingy here: Nissan 370Z Forum - Conversation Between 12nismo and wstar about whether the engine failure was pulley-related and whether I moved my crank pulley to my new block. The TL;DR answer to that is: I *think* the failure was unrelated to the pulley, but I also did *not* move the pulley over to the new block.

..........................

Our engine is an internally-balanced one, meaning the pulley doesn't play a role in basic rotating-assembly balance issues on this car. It *does*, however, contain a rubber vibration-damping ring on the outer face of it. The core of the real debate here is whether the purpose of that vibration damping ring is purely for aesthetic NVH reduction, or whether it has a real dampening effect that partially reduces some mechanically-important crankshaft vibrations from combustion (and if so, how much longevity are you losing if you eliminate this? It could be 5%, it could be 95%!).

Have just come across this thread and read selective bits from it ....

To add my 2-cents worth to the pulley debate, on a DD that sees a "big" rev every now and then .... probably not significant, BUT in a competition car, an un-damped pulley is an engine killer in my book.

Back in the 80's, when I built the race-car I have come back to (is an historic 70's sports car, Buick 215 V8 engined), I ran without a crank-damper for the first 3 seasons and lost 4 engines (crank main-bearing failure each time), at which time we moved to dry-sump AND a damper.

We've had engine failures since, but never crank main failure - usually down to running the rod-bolts a tad too long (Carillo's are lifed at 80 hours, but we now replace rod-bolts (7/16" now rather than 3/8") every 40 hours as a precaution.

You only have to speak to the guys in the UK (IES - who prepare the GT3 NISMO GTR and also the 370Z GT4 engines for RJN Motorsport who run these cars in the Euro GT3/GT4 and Blancpain championships for NISMO) and they NEVER run an engine without a damper.

In the USA, talk to JWT who build the Grand Am engines for the Nissan 370Z runners, or Unitech Racing who built the Fontana Racing 350Z's - they all have recent experience of VQ race engines and I am quite confident they will specify a quality damper. In Canada, Sasha Anis also has a wealth of information about the VQ engine in competition-spec.

The NISMO engineer in Melbourne who assembles the VK engines for the Nissan Motorsport Altima's in the V8SuperCar series also specifies a motorsport damper and these are 5-litre engines making 650hp.

If it is good enough for those guys, it is certainly good enough for me, BUT as always, make up your own mind and tread your own path.

RB

wstar · 06-30-2014, 06:42 PM

Your points are well-taken. I have no doubt the math makes sense on a racecar. You lose a little tiny bit of throttle response and power and you gain reliability. It's also a spec engine putting out gobs of power with insane throttle response, so the damper hit is hard to feel in the first place, and no matter what it does to your power you're going to tune the thing right back to your desired spec horsepower or whatever. On a plain stock engine, the throttle response difference is notable (and I suspect, a reason for my perception of felt changes in upshifts on my new block - revs just aren't falling as fast).

Your random data point about 40-80 hours is interesting as well. Using very approximate, rounded-off, numbers, my stock engine had 40K street miles on it before it left the street for good, and ~4K track miles on it (I had mis-estimated this as more like 5K earlier on). Those 4K track miles occurred over the course of approximately 80 hours of track time (The rough figures I'm using for easy approximation is 40x singular days of DE, ~100 miles over 4x 30minute sessions per day).

Keep in mind this block was sealed up at the factory back in late 2008 and never opened or worked on again. That it survived this long was a miracle (and maybe thanks to religious maintenance where I could on things like regular high-quality oil changes, and the baffled oil pan I picked up from AM Performance, and good cooling). I really think the flywheel flopping around is what did in the crank bearings at the end. Had I thought to check that and correct it earlier, the engine might've gone longer. Still, something had to give. I highly doubt I'd have made it to 10K miles no matter what I did (well, short of actually rebuilding the block before it fails).

Which brings me around to the situation I'm facing now: how to adapt to and cope with where I'm at in my ever-evolving hobby. If I keep up with anything like my current schedule of DE events and expect engine failures at about this sort of interval, I'm looking at a dead engine block every 2 years if nothing goes unusually-wrong. It's tempting to say "Yeah but I can't afford the time or labor cost of having the engine rebuilt correctly on regular maintenance intervals", but that's probably not true. If I don't, I'll be doing the same rebuilds but with less predictability and more downtime. Of course there's all the other components to keep track of as well. How long do good-quality spherical bushings last? Shocks? Rear ends? Transmissions?

Figuring all this stuff out from scratch the hard way is a trying experience at best, given I'm a one-man pit crew with no qualifications to speak of and doing this for fun with no sponsorship dollars or any real plan to go after real racing (I'm closing on 40 and started too late in life to ever be good enough for a top-tier race series, and I like my well-paying day job).

While all of the above sounds pretty depressing and daunting, in many ways it's kind of awesome, too. In the same way that track-driving stretches my skills and my brain in painful but ultimately rewarding ways, so does all the rest of this stretch me in other areas. On the days when it doesn't totally defeat you, it feels pretty awesome to still be doing it at all

06-17-2014, 02:58 PM	#811 (permalink)
wstar A True Z Fanatic Join Date: Mar 2009 Location: Houston, TX Posts: 4,024 Drives: too slow Rep Power: 3594	Yeah, so someone asked on the "visitor messages" thingy here: Nissan 370Z Forum - Conversation Between 12nismo and wstar about whether the engine failure was pulley-related and whether I moved my crank pulley to my new block. The TL;DR answer to that is: I think the failure was unrelated to the pulley, but I also did not move the pulley over to the new block. The long explanation, if the above is important to you and/or confusing: Personally, I don't think the (Stillen, light/underdrive) pulley was a significant factor. My best guess is the flywheel probably started cracking a long time ago, adding some imbalance/wobble to the crankshaft and beginning to cause excess wear in the crank bearings, and then when the flywheel finally got bad enough (when the last bit cracked on that fateful Saturday), we had some major imbalance/wobble/whatever going on that really tore up the bearings, along with the flywheel striking the crankshaft position sensor, which is what caused the engine to go into limp mode at that point. Even then I think the bearings were merely damaged at that point, but not seized/spun, initially. They didn't really come apart until test-fires and moving the car around around later, off-track (but that was inevitable at that point, they were shot one way or the other)... which brings us back to the Great Internet Pulley Debate (which rages forever on almost every car forum), where pulley-detractors tell us that lightweight pulleys without dampening rings on them will destroy crankshaft bearings over time. To recap the basic internal/external balancing stuff, open the spoiler (or you can skip this as a TL;DR reduction if you get this part already): ( Click to show/hide ) The balancing of the rotating assembly (crankshaft, connecting rods, pistons, counterweights, and yes, also the flywheel and pulley) is critical in all engines. This is the same "balancing" you hear about when people talking about blueprinting and balancing a custom/race engine. Factory engines are balanced at the factory. If the rotating assembly isn't balanced to within a fine tolerance, it will destroy itself and/or the bearings it rides on fairly quickly. Some engines are designed to be internally balanced. This means the crankshaft and attached internal components (counterweights, connecting rods, pistons) are balanced against each other for a net of zero. At that point you can stick whatever you want on the ends (pulleys/flywheels) and things remain balanced so long as those components are also evenly balanced. Some are externally balanced (including many notable V8's people like to work on), meaning that they rely on offset weights in the crank pulley and/or flywheel to come into full balance. If you were to replace the pulley or flywheel with a different model that didn't have the exactly-correct balancing weight on it (e.g. 50 grams of excess weight at 5 inches radius at 120 degrees or whatever), your whole rotating assembly is no longer balanced correctly and you're going to have problems. Our engine is an internally-balanced one, meaning the pulley doesn't play a role in basic rotating-assembly balance issues on this car. It does, however, contain a rubber vibration-damping ring on the outer face of it. The core of the real debate here is whether the purpose of that vibration damping ring is purely for aesthetic NVH reduction, or whether it has a real dampening effect that partially reduces some mechanically-important crankshaft vibrations from combustion (and if so, how much longevity are you losing if you eliminate this? It could be 5%, it could be 95%!). Anecdotally, I don't think it's much of a loss, if any, because the pulley kits from NST and Stillen (and others) have sold tons, and we're not hearing about massive lawsuits or even complaints about destroyed engines. It's most likely that the ring is mostly about NVH. Maybe it also reduces some mechanical vibration that matters, but maybe that's not very significant to begin with. For this sort of reasoning, I'm generally of the opinion that you're not risking any kind of large or short-term damage by properly installing a pulley kit on this engine. That and my engine made it through a considerable number of very abusive track miles on such a pulley (and even then, I don't think it was the cause). However, I can't in good conscience say that without adding 3 important disclaimers/caveats: My car is a 7AT, not a 6MT. Vibrational issues could be different on the two. I tend to suspect that, if there is any issue, 7AT's would fare better than 6MTs. This is because a 7AT has a torque convertor full of transmission fluid bolted to the flywheel at the rear of the engine. I suspect the torque convertor acts like a giant fluid damper on the rear of the engine (e.g. The Original Fluidampr ), offering far better vibration damping than any silly rubber ring on a pulley ever could. Regardless of all the logical weaseling above, you can't escape a few basic facts: Vibration hurts engines. All engines vibrate. There's a small rubber ring on the stock pulley that may help with some unknown vibrations to some unknown degree. You're tossing that out for a <1% difference in the engine's performance capabilities at the end of the day. Maybe that's worth it, maybe it isn't. How much stress you're putting on the engine to begin with is a big factor. If I were building a 750rwhp turbo monster, I'd probably go in the opposite direction and install a heavier replacement pulley that does some serious damping to increase longevity. On an N/A street engine, I doubt you'll ever know the difference (in performance or longevity), making the upgrade pointless. Jason (the mechanic who did the swap, and who I think has a trustworthy opinion about all car things) recommended against moving the pulley over to the new engine when moving all my other stuff over, because he thought it could have been a factor, and it's not worth the risk if it was. While, academically, I may believe it to not be a major contributing factor in the failure, I don't believe that strongly enough to tell him "No, put it on anyways", especially given that I could end up destroying this replacement block in a short period of time via something totally unrelated and coming right back to him with it, at which point he'd get to say "I told you so" about the crank pulley whether it was the issue or not, because that's only fair at that point. So he put my stock crank pulley on the new block, and that's what I'll be running for the foreseeable future (until I kill this engine in some new and imaginative way!). 12nismo likes this. __________________ 7AT Track Car! Journal thread / Car setup details Last edited by wstar; 06-17-2014 at 03:13 PM.

06-17-2014, 03:00 PM	#812 (permalink)
theDreamer A True Z Fanatic Join Date: Feb 2009 Location: Texas Posts: 30,879 Drives: 370z Rep Power: 4210	12nismo is cobb in Houston. He is getting his pulley put on this week so wanted to make sure your engine failure was not related. __________________ theDreamer's Z // Fast Intentions // Uprev // GTM // HKS // TEIN theDreamer's Silvia // URAS // GREDDY Houston Zs // Facebook // Twitter // Instagram

06-17-2014, 03:10 PM	#813 (permalink)
wstar A True Z Fanatic Join Date: Mar 2009 Location: Houston, TX Posts: 4,024 Drives: too slow Rep Power: 3594	Apparently he's already doing it. Unfortunately I don't have any easy answers for him, hence my huge diatribe above! Maybe an appropriate closing statement would be: if I could rewind time and start over, I'd still have put the same pulley on my (7AT-, NA-, track-) car back when I did. 12nismo likes this. __________________ 7AT Track Car! Journal thread / Car setup details Last edited by wstar; 06-17-2014 at 03:30 PM.

06-17-2014, 04:01 PM	#814 (permalink)
12nismo Base Member Join Date: Apr 2012 Location: Houston, TX Posts: 153 Drives: 2012 370z nismo Rep Power: 15	Just got the kit installed and I'm very happy with the results...as long as the motor holds up, lol. __________________ nismo Z34 12 0209 JTran Motorsports//Stillen//Fast Intentions//EcuTek//Z1 Motorsports//Eibach//BRIDE //Zspeed//Carbon Signal//Houston Halos//Southbend//Whiteline//TWM//NonStopTuning//Doran Racing

06-19-2014, 06:30 PM	#816 (permalink)
wstar A True Z Fanatic Join Date: Mar 2009 Location: Houston, TX Posts: 4,024 Drives: too slow Rep Power: 3594	Well, I'll certainly at least pull the starter and access covers and take a look at it from time to time. I suspect there was a good amount of lead time between the first crack and the bad situation at the end, but "inspect the flywheel" was never really on my track prep checklist before I've got my old block back at home now with an engine stand as well. I plan to get that one rebuilt stronger and then drop it back in the car at a later date. Once I get to see the extent of the damage I'll know how much basic work needs doing and whether the block needs to see an engine rebuild shop first (probably). Once the block is basically sane, I'll probably drop in a bunch of upgraded parts for durability (e.g. Nismo oil pump, GTM HD flex plate, custom water inlet/outlet stuff with good fittings and no stupid heater connections, etc). Depending on time contraints, budget, and craziness, I might go further and build it up into something awesomer (e.g. one or more of 4.0 stroker, lots of forged high quality internal bits, dry sump, custom race ECU, etc). Right now the budget picture is pretty bleak while I recover from replacing the engine in the first place, but that will turn around in a few months. __________________ 7AT Track Car! Journal thread / Car setup details

06-17-2014, 08:52 PM	#815 (permalink)
VoBoy Base Member Join Date: Mar 2009 Location: Chicago/Houston Posts: 37 Drives: 06 350z Rep Power: 16	so just curious, what's your preventative don't blow up the engine plan in the future? flywheel replacement every 1 to 2 years?

06-19-2014, 06:39 PM	#817 (permalink)
wstar A True Z Fanatic Join Date: Mar 2009 Location: Houston, TX Posts: 4,024 Drives: too slow Rep Power: 3594	Also, I took the still-unused 265/645 Wets off of my extra 18x10 wheels and had the 285/645 slicks mounted. The rims still aren't well-protected, even though I'm sure 10 inches is a good width for these 285's. Part of the issue is probably that race tires don't have rim-protectors built into the rubber mold, and that these Forgestars have particularly thick rim edges. When stacking these on their sides, the metal of the wheels don't touch each other or the ground, but it's just by a hair's width. Set them down too hard and you can hear them click into each other. I think I just have to live with that for now, because otherwise this setup should work great for trying out these cheap slicks. Assuming no other major issues get in the way (like my car blowing up and/or dying), I think my general plan at MSR-H this weekend is to spend most of the weekend on my existing RS3's, then maybe switch the slicks on for the 3rd or 4th session Sunday and scrub them in over a whole session slowly coming up to full speed. Then they'll sit for a week for that whole mfg-recommended rebonding process and I'll try them again at COTA the next weekend (with the remaining life on the RS3's as a backup option. I might even start out on the RS3's and then switch to the slicks later in the weekend instead, so that I'm super-comfy with the track/event before adding that new challenge back into the mix. All depends how things feel during the scrub-in session this weekend). Pics, off the car sitting at 25psi cold pressure (I suspect I might need to start them even lower than that, still researching): iceman21_23 and jlo370z like this. __________________ 7AT Track Car! Journal thread / Car setup details

06-19-2014, 07:56 PM	#818 (permalink)
sig11 A True Z Fanatic Join Date: Jun 2009 Location: Detroit Posts: 1,294 Drives: 09 370Z Red Sport-MT Rep Power: 18	You won't want to go back to the RS3s!

06-20-2014, 11:14 AM	#819 (permalink)
Mike The370Z.com Sponsor Join Date: Jun 2009 Location: Loganville, GA Posts: 5,944 Drives: 370z Rep Power: 2186	I shoot for 36 hot on them. Not quite the same grip as the A6s, but still a great tire. __________________ NISSAN: 75 280Z / 86 300ZX GLL /87 Sentra SE / 03 350Z / 23 Z Porsche: 93 968 / 23 Macan GTS / 93 968

06-23-2014, 08:51 AM	#820 (permalink)
wstar A True Z Fanatic Join Date: Mar 2009 Location: Houston, TX Posts: 4,024 Drives: too slow Rep Power: 3594	Had a great weekend at MSR-H! New engine seem to be running great! Only have a couple minor things to look into: oil temps looked a little higher than expected (240-ish but it was a very hot weekend), and upshifts were a little slow and clunky on Saturday (but gradually got better for some reason; could have been me subconsciously adjusting shift timing or lifting throttle. Could also be that the fluid level's a little off?). Car's already back on my mini-lift for basic maintenance. Going to swap out the engine oil (since this was the first fill for that engine since the salvage lot), check trans fluid level, replace front rotor rings (finally, and replace studs+lugs while I'm in there), bleed brake fluid, etc for the coming weekend at COTA. I did my Red-group check ride for MSR-H (Driver's Edge does these per-track, so the one at TWS was separate from this) on the first Sunday session and that went great, so I got to spend half my weekend in Red. Kevin was my check-ride instructor; his line advice was amazing, but it will take a while for me to get out of my old habits and pick up speed from what he was saying I did scrub in the Conti GT-O slicks in the final session Sunday. As usual, my fears were all in my head. There was no problem controlling that tire, and it felt amazing. We had about 8 hot laps that session. I spent the first 6 slowly edging my way up on laptime and trying not to put any big slip angle in them, then the final 2 laps I ran at my normal pace for the RS-3's and I could finally start to feel a little slip. You could tell the tires were nowhere near their limit at my RS-3 pace. At places (and speeds) where I'd feel unstable or fighting the car way out at the edge of acceptable traction in the RS-3, the Contis were just rock solid and predictable. There's clearly 2-3 seconds I could take off my laps here if I adjusted my pace up to the tire's limit with slicks like these. (Then again there's also clearly 1-2 seconds I could shave if I made some basic line fixes; who knows how much those two figures overlap). Also, they look great on the car -- Fastest lap for the weekend was 1:52.21 (second-to-last session of the weekend, still on the RS3's): Megan370z, guru, Rusty and 1 others like this. __________________ 7AT Track Car! Journal thread / Car setup details Last edited by wstar; 07-18-2014 at 09:41 PM.

06-23-2014, 09:31 PM	#821 (permalink)
wstar A True Z Fanatic Join Date: Mar 2009 Location: Houston, TX Posts: 4,024 Drives: too slow Rep Power: 3594	I went ahead and encoded the whole session that the fastlap above came from. Spent that whole session chasing down the same red Lotus (well, once he got back in front of me around the end of Lap 4). Lots of data to pick up from it on how and where he was faster than me. Mostly, it seems like he was doing better pushing out of the inner carousel wider and earlier on the throttle, and he was way more gutsy staying in the throttle before, during, and just after The Launch (the little hill): Rangerz, carlitos_370z and Limeybastard like this. __________________ 7AT Track Car! Journal thread / Car setup details

06-23-2014, 10:10 PM	#822 (permalink)
Mike The370Z.com Sponsor Join Date: Jun 2009 Location: Loganville, GA Posts: 5,944 Drives: 370z Rep Power: 2186	240 is probably just normal in summer. I saw 230 at road atlanta weekend before last, and Russell from Z1 and Brian Kleemans Pirelli challenge car were around 260-70, but my stillen bumper probably helped me. this weekend at AMP which doesn't have long straight and is shorter, I was in the 230-240 range. It is summer! __________________ NISSAN: 75 280Z / 86 300ZX GLL /87 Sentra SE / 03 350Z / 23 Z Porsche: 93 968 / 23 Macan GTS / 93 968

06-23-2014, 10:17 PM	#823 (permalink)
wstar A True Z Fanatic Join Date: Mar 2009 Location: Houston, TX Posts: 4,024 Drives: too slow Rep Power: 3594	Time for hood vents I guess Mike likes this. __________________ 7AT Track Car! Journal thread / Car setup details

06-30-2014, 06:42 PM	#825 (permalink)
wstar A True Z Fanatic Join Date: Mar 2009 Location: Houston, TX Posts: 4,024 Drives: too slow Rep Power: 3594	Your points are well-taken. I have no doubt the math makes sense on a racecar. You lose a little tiny bit of throttle response and power and you gain reliability. It's also a spec engine putting out gobs of power with insane throttle response, so the damper hit is hard to feel in the first place, and no matter what it does to your power you're going to tune the thing right back to your desired spec horsepower or whatever. On a plain stock engine, the throttle response difference is notable (and I suspect, a reason for my perception of felt changes in upshifts on my new block - revs just aren't falling as fast). Your random data point about 40-80 hours is interesting as well. Using very approximate, rounded-off, numbers, my stock engine had 40K street miles on it before it left the street for good, and ~4K track miles on it (I had mis-estimated this as more like 5K earlier on). Those 4K track miles occurred over the course of approximately 80 hours of track time (The rough figures I'm using for easy approximation is 40x singular days of DE, ~100 miles over 4x 30minute sessions per day). Keep in mind this block was sealed up at the factory back in late 2008 and never opened or worked on again. That it survived this long was a miracle (and maybe thanks to religious maintenance where I could on things like regular high-quality oil changes, and the baffled oil pan I picked up from AM Performance, and good cooling). I really think the flywheel flopping around is what did in the crank bearings at the end. Had I thought to check that and correct it earlier, the engine might've gone longer. Still, something had to give. I highly doubt I'd have made it to 10K miles no matter what I did (well, short of actually rebuilding the block before it fails). Which brings me around to the situation I'm facing now: how to adapt to and cope with where I'm at in my ever-evolving hobby. If I keep up with anything like my current schedule of DE events and expect engine failures at about this sort of interval, I'm looking at a dead engine block every 2 years if nothing goes unusually-wrong. It's tempting to say "Yeah but I can't afford the time or labor cost of having the engine rebuilt correctly on regular maintenance intervals", but that's probably not true. If I don't, I'll be doing the same rebuilds but with less predictability and more downtime. Of course there's all the other components to keep track of as well. How long do good-quality spherical bushings last? Shocks? Rear ends? Transmissions? Figuring all this stuff out from scratch the hard way is a trying experience at best, given I'm a one-man pit crew with no qualifications to speak of and doing this for fun with no sponsorship dollars or any real plan to go after real racing (I'm closing on 40 and started too late in life to ever be good enough for a top-tier race series, and I like my well-paying day job). While all of the above sounds pretty depressing and daunting, in many ways it's kind of awesome, too. In the same way that track-driving stretches my skills and my brain in painful but ultimately rewarding ways, so does all the rest of this stretch me in other areas. On the days when it doesn't totally defeat you, it feels pretty awesome to still be doing it at all BGTV8 and 12nismo like this. __________________ 7AT Track Car! Journal thread / Car setup details Last edited by wstar; 06-30-2014 at 06:55 PM.

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