I haven't had any problem with overheating at the track. I've had phenomenal luck in the past two years to have almost no hot track days. Tomorrow will be the hottest day I have run at 92. So we will see. I'm more concerned about g-forces. Although, I believe the Grand-Am cup cars have had no oiling problems. So maybe I'm just paranoid.

 

Sentry,

I blew the stocker.

My quarter times were run with the Tilton, 3.9, 295/35 T1S's, ECU, Cat deletes, pulley and Y-pipe. BTW, I did not reinstall the crank pulley on my new motor.

To answer one of your original questions, I dynoed 262. Now I assume I'm in the neighborhood of 250's with the removal of the pulley and ECU. Although, I have added a B-pipe recently so maybe I'm back up in the 260's.

 

I have a 7300rpm rev-limit on my Twin Turbo 350Z, haven't had any trouble and see 7,200 rpm frequently. One advantage of a raised rev-limiter is that you can shift at redline on the tack without hitting the rev-limiter.

If you have a supercharged setup you will most likely continue to make more boost as the rpms increase. You will want to make sure you are not running more boost than intended and/or have the proper amount of fuel to sustain boost above 6,700rpm. It is also EXTREMELY important to have your timing maps modified before running over 6,700rpm!

Hope this help,

 

A stock Z's peak HP comes waaaaaaaaaaaaaaay before 7100 RPMs. Even with an ECU, you're probably making your peak HP right around 6000. No need at ALL to keep going. In fact, reving beyond your peak slows you down. You should shift right as your torque curve starts comming down. That puts you climbing up your power band in the next gear. Reving too high (past your peak) and you'll land right on top of your peak, but the car will begin to lose horsepower the longer you're in that gear. Horsepower doesn't magically keep going so long as you press the gas...unless you have a turbo.

I keep saying this, and one day someone will look at a dynochart and realize it.

 

my peak hp is beyond 6600rpms with my NA mods - think it's at 6800 or so

 

Why did you not reinstall the crank pulley? You wanted to keep the steering light so you can catch the back end quickly?

 

my car sees 7k every single day....not a single problem to date. I was among the first 04 to have an Altered flash (they use the techtom software). Car makes 269 at the wheels in its present state, soon to be a bit over 300 whp

the flash for me was an awesome mod, but like anything software related, its all in the person punching the keys

 

I did not reinstall the crank pulley, because there is some controversy over its effect on engine longevity. I am in the camp that says that crank pulleys don't hurt the engine. But after you blow one, no matter how sure you think you are, you will still be a little more cautious.

 

Well you need to stop saying it, b/c you are wrong.

The mild drop off in power above peak is outweighed by the gear multiplication of the lower gear beyond peak. Talk to anyone who seriously drag races this (or pretty much any) car and he'll tell you to run it to redline to get down the track the fastest. Sorry if I sound harsh, but I continue to see this misinformation spread ad naseum and it has become a pet peeve of mine.

There is a chart someone posted once showing the actual power to the wheels in each gear at speed...I'll look for it to link or repost as it proves my point.

 

ditto

 

agreed as well - and fwiw my hp is consistent to redline, but torque is what falls off

 

Peak HP comes at 6200rpm stock, engine will produce power all the way to redline.

dyno proven

With the correct combination of bolt-ons, engine will produce power up to 7000 rpm easy..

 

That's interesting... food for thought indeed.
even though the rod failure is hard to attribute to crank pulley (it could, but you would have had lot's of symptoms)... I still understand your point. Really a shame we can't pinpoint the cause of the failure.

What I'd like to know, and sorry if I missed it, was your oil consumption levels and what oil where you using when engine blew. And did you have major missshifts before engine blew? (8000 rpm downshift, revlimiter abuse, etc...)

I wonder if it's possible to have 7000rpm limited spec flash instead of 7100. I'd prefer a 7000rpm redline and have 200rpm safety buffer RPM. Nismo reccomends rodbolts ABOVE 7200rpm.

 

mine goes to 7100. i set my shift light at 7k and hit 7k at least once daily, just for giggles.

 

I'm pretty sure TS can set the the redline at anything you want.


Another Z driver was recently at the dealership that warrantied my motor and he said the block was still stitting there. Maybe I could get over there one day and take some pics of the damage and let you guys diagnose it.

I don't remember the oil ever being low in between oil changes. However, I did change it very regularly because of the harsh abuse I was giving it. I can recall one over-rev last year at Road America. Probably hit 7800-7900. The car did not seem the worse for wear in the months after.

The day the motor blew, I was driving down to the track and there were some essess on the way. I stepped on it to push through them a bit and something just didn't feel right. I couldn't put my finger on it, but something felt off. I even mentioned it to my wife. The symptoms were not bad enough to warrant much attention, but it was off. If I had to describe it I would say the the throttle response was dulled. I checked the car over a bit when I got to the track and nothing seemed wrong. By the 5th or 6th lap in on the first session, the rod gave way.

I'm not trying to scare anyone with my story. I think the VQ has proven itself as a pretty stout motor. But if you have a stack of these at your house, you might be in danger. Alberto how many runs you got in?? LOL!! Counted my slips, 104 quarter mile runs in the course of a year and a half.




Oh yeah, I took one more precaution too. I bought a trailer to tow the beast everywhere I go now. So if I flog it to death again, I can just tow it home.

 

Nano:

As I understand from nismo's website... they recommend their rod bolts to be used only up to 7200rpm not beyond and if it is above that, I guess changing rods might be a better way though..

cheers,

richie

 

Wow tell me something I dont know I asked him why he shifted early now, because he said he short shifts at under 6000 rpm's, a stock Z peaks at 6200 rpm, I never said he should shift at 7100rpm, go back and re-read my post. And your hp doesnt keep going as long as you rev it with a turbo, you dont know what your talking about. Go look at a 1.8T GTI or WRX/STI dyno chart power falls off up top, just because a car has a turbo doesnt mean it will make power till redline.

Damn, lol. I have only ran my car maybe 20-25X. Only ran it 3X stock. My first pass stock I hit 13.80@100. Second pass was 13.77@101 Third pass headwinf picked up slowed to a 13.86. And the other times Ive ran it with different mods along the way to the set-up I have now.

 

To be clinical a car accelerates according to it's Tq capability not Hp (gearing/rpm/torque) the most efficient output (acceleration) from a car occurs when you shift to the next highest gear right after you have reached the max safe tq that that gear/rpm achieves. Hp should not be the basis for the shift point.Acceleration does not occur as a result of Hp. Acceleration occurs as a result of Tq..The way to determine the safe shift points for a particular car is to put the car on a load based dyno and determine the safe Tq vs gear/rpm..IMHO...Safe has been highlighted to stay out of the red line for the gear..

 

I agree with your torque vs. hp comment. The graph I was looking for illustrates gear multiplied torque delivered to the wheels. I did find the original image link, but it is broken now. Anyone know who this is?

http://www.marksink.com/350Z/WHEELPOW.jpg

 

I have the twin turbo set-up and TS 7psi turbo reflash for a year now. The car is doing 380whp @7.5psi, 12.9@112mph and I floor the car every single day (speed junkey) and have had no problems at all.