whosurdaddy

Some of you may have noted my earlier post on this topic where I blew the motor in my 2006 Z06 with 34000 miles. I have learned quite a bit since the original post and felt it important to share it here. Short-Throw was very helpful in getting me connected to the Corvette Drivetrain Quality Assurance Manager who provided the below:

1) The 2009 Z06 will indeed have an upgraded dry sump system. The new system will have an add-on (sidecar) tank that will hold an additional 3qts of oil. This system has been designed to be retrofitted to existing 2006-2008 Z06's as a high-performance upgrade and will be available in the fall. The price is unknown at this time.

2) 2006-2008 Z06's were engineered to accommodate up to 1.2 lateral G's. Anyone tracking their car hard and/or using R compound or better tires are subject to exceeding these limits and therefore allowing the oil system to ingest air via the inlet at the tank during high-G's. The resulting aerated oil would obviously negatively impact the engine. This is supposed to be addressed via #1 above.

3) Springs have been failing and causing valves to drop, though GM isn't certain of the reason. Proactive aftermarket replacements could impact the warranty, though Katech offers a set with titanium retainers that they sell for $512

Reviewing my data from the past two years, I found a number of instances where I exceeded 1.2G's (many times each lap) on both the stock Goodyears and Michelin PS2's. In particular, through several carousels where a high G-load was maintained for quite a period of time. Peak G's seemed to be just north of 1.5. I can't imagine what's going on inside the motor of those who are running on race rubber without an improved oiling system.

Also, the predominance of corners are right-hand, which would throw oil to the left and away from the right. It was #6 (on the right) that failed (though I'm not sure if this issue works this way or not, seemed like a strange coincidence to me).

So, if you track your car, you should exercise extreme caution or risk motor problems. Now I'm in a quandary - what do I do this track season before the "Side-car Mod" becomes available? Drive at 6/10th or something?

I have pictures and will share as soon as administrators approve them in my gallery.

Mjolitor 68

Thanks for the info

Good to know

Havent tracked my Z yet but its only a matter of time

jsb08Z

Lingenfelter also has this modification to the dry sump tank that will allow additional oil and higher g loads more safely. You could do this prior to GM release of their product.

whosurdaddy

I'll check it out. Thanks!

805Z06

Not to stir the pot. But if the Z06 needs extreme caution at the track that would be BS.

This high performance car needs to fill a purpose. If it's going to have to drop valves for some random reasons, fine.

But if GM is hinting this..that would be extreme bs, considering how they promoted the cars capability.

If the future holds true that the Z can't be played at the track for high risk of damage, bye bye Z...leave it for the older Zaino guys at the engine show hangouts

I would hate for GM to support such a claim, that would be suicide to the ultimate performance car.

whosurdaddy

The LPE mod. Seems to be inexpensive insurance.

http://www.lingenfelter.com/store/l300046006.html

whosurdaddy

I don't know why they would engineer to 1.2G's when this seems to be easily exceeded on street rubber. My guess is that they didn't know of the problem and mapped it back to a max of 1.2 when they became aware of it. I think this is why they are advertising the ZR1 as capable of achieving 1.5G's. Since LPE's upgrade can is so cheap, I'm guessing GM's will be in the same ball-park.

805Z06

A Miata can pull more than 1.2gs without problems. It's like saying they didn't expect drivers to drive it faster than 65-85 MPH.

I can tell you a lot of guys didn't spend $70k to buy a Chevy. They bought this car so it could outperform a Ferrari at the track as proven on all their ads. For the other guys, ya bring out the beach chair and hangout at the parking lots.

The ZR1 is not all that, it has a supercharger slapped on. Most track guys will tell you that superchargers are not meant for the track. It's still a sweet ride but I would not consider it a track toy over the Z06.

I think GM needs to take some responsibilities for any shortcomings. Instead of spreading rumors through forum members about tunes and NOW saying that these problems are steamed from track use

Just imagine this in the near future, more engines blows and forum members starting threads saying track use will void your warranty.

kentz06

Did you ever find out exactly what failed in your motor?

whosurdaddy

No. I've seen through an intake port that a valve has dropped. I also have a piston sticking through my block. Thus far I'm unsure what came first. We'll pull it appart some when it comes out (next week) and I'll post pictures of the result.

klasik-69

According to the people at Spring Mountain, Corvette tested their prototype Z at their track when initially using a wet sump system. The engine failures is what brought them to use a dry sump system. I'm assuming they ran the car hard at Srping Mountain after installing the dry sump and would have exceeded 1.2 Gs, and if there was an issue, they would have found it. I don't doubt some people are having issues with their motors to include dropped valves, but isn't that par for the course with high perf motors used on a track ?

I think if there were issues with these motors above and beyond normal expected failure rates, Spring Mountain would be aware of it and would have modified or curtailed the use of their 20+ Vettes on their track for HPDE training. Of the 20+ vettes, roughly 6 are C6Z06's, 12 or so are C6Z51's, 2 or3 are C5Z06's. I've been to both their level I and II courses and not one mention of failures. One of the C6Z06 cars had over 30,000 miles of pure abuse. What is the real failure rate ? Is it less than 2% ? If so, isn't in line with Porsche, Ferrari, Lambo, etc. failure rate as well ?

Dicecal

Good words! I'll be interested in the dry sump upgrade when it's available!

linutux

As the waxers say, this thread is worthless without pics...



Here's a pic of the cooler alone:


Does anyone know if you need BOTH the pan AND the cooler? Or will the cooler bolt on to the old pan?

Gannet

What cooler? I'm not following how that little thing is any sort of cooler.

John Shiels

Glad my LS6 with 6000 track miles has survived with an Accusump from DRM and way more than 1.2 G's I am sure.

yanniz

Accusump is definitely an easy way to help the situation...

JLMounce

I think the key here isn't necessarily peak G, but sustained. This isn't going to be a problem for 90% of the people that track their cars, even on R compounds.

Why? Because 90% of the cars aren't on a track with long high speed sweepers that could sustain that amount of lateral loading long enough to cause the issue.

whosurdaddy

Pictures:
Holey block Batman!


Dropped valve at #6

imp zog

Hi John, would you mind posting info (or PM me?) on the model and how you mounted the Accusump for your LS6? I'm looking to do the same this spring, as well as a cooler. Thanks!

imp.

Dirty Howie

Thanks for the info.

I am glad to here this will be retrofited to work with an 08 which I just bought and expect to track. I hope its a reasonable cost.....seems like it would be in GM's interest to see us all add it on.

AND it should be warraneed if we add it and not affect the original warantee.


DH