Originally Posted by Enchanter

Interesting. I've run 'Seca 4-5 times in my stock 2007 Z and never had a problem. I've even had the butterfly's open the entire time, with no issues.

Originally Posted by Viper_Vette

I don't believe his car is stock.

Originally Posted by mikymu

It's almost impossible to pass sound at Laguna Seca with flaps open unless you really snail pace up T5

Originally Posted by Viper_Vette

Didn't you put headers and a full exhaust on your car? I could of swore you made a thread in the past on it.

Originally Posted by LEE427

I also ran into some of the same problems of other ppl not pointing me by. Then I get accused for it when traffic occurs. Never had these problems before running at other track events by other clubs/organization.

Originally Posted by jdhommert

no his car has a ginormous wing on it

Originally Posted by LEE427

First time with my new Z out .With that being said,I also ran into some of the same problems of other ppl not pointing me by. Then I get accused for it when traffic occurs. Never had these problems before running at other track events by other clubs/organization.

Originally Posted by Bedouin

Mikymu...thanks for the awesome write-up on the solonoid bypass..hugely helpful, as my LS3 (Pfadt headers, cat'd x-pipe & stock dual-mode mufflers) registered 102db last time @ L-S during a 105db day.

Originally Posted by Ludedude

So if I'm following correctly, your mod enables you to switch the valves in the forced closed position so no change in sound at 3500 RPM yes? YES

I'm wondering if I need to do that to my car prior to the upcoming 105 dB day that Speedventures is having in June. Only reason I can see that my car is as loud as it is is due to a) the fuse is pulled on the dual mode exhaust and b) apparently someone did the muffler mod surgery before I acquired it. Stock manifolds, cats are present, after market CAI. As far as I can figure, it's like running straight pipes out the back.

Originally Posted by AzDave47

The muffler mod makes the car louder, but mostly when the flaps are closed.

Originally Posted by mikymu

Installing a switch to control the exhaust flap is highly recommended. It's not a good idea to run the flap closed all the time since exhaust heat flow at high RPM may damage the mufflers when driven hard

Originally Posted by AzDave47

With the stock manifolds and cats, you should be OK, noting that sound measurements can vary day to day and with the weather. The muffler mod makes the car louder, but mostly when the flaps are closed. Once the flaps are open or the fuse is pulled, you would be just about the same as the stock muffler as the open pass thru the muffler controlled by the flaps will carry most of the exhaust and sound.

Doing either the exhaust flap solenoid jumper or safety wiring the flaps closed will get you well under the 105 limit with the flaps closed so you should be prepared to do either unless they only give you one shot to pass, in which case, you will want to do the test with either of those mods.

Originally Posted by mikymu

Took my Z06 to Laguna Seca for the first time on Saturday's PCA event. Wow! this Z06 is just fantastic! I had 12+ heat cycled Hoosier R6 and I flip it to get some more life and still managed 1:38 in traffic. Car handled all the twist and turns beautifully and I had full confidence even when I lost it a bit coming out of T11.

It was a super hot day and easily over 85F. The coolant temp was much higher at about 230F after 20+ min compare with 210F at Thunderhill. I figure the higher temp must be due to the constant ups and downs and higher elevation changes on the track.

I am sure most of you are aware of the ridiculous sound limit at Laguna Seca. It could be either 90 or 92 db depends on the county rule. Stock Z06 and ZR1 will not pass sound unless you wire the two muffler flaps closed. I have LG headers, 200 cell cats and Akrapovic rear mufflers so it's loud! In the past I had success in passing sound at Laguna Seca with my GT3 RS and also GT3 Cup car with a simple 3.2 seconds fix: http://forums.rennlist.com/rennforum...2-seconds.html

You can also opt for a fancy switch in the car so you can control the muffler flaps at your finger tip: http://www.6speedonline.com/forums/g...inger-tip.html

It turns out that our Z06 and ZR1 have the same exact vacuum solenoid ... well, almost exactly. The GM vacuum solenoid do not have the same vacuum release "pipe" where you can simply cap it and maintain the vacuum and keep the exhaust flap close. Luckily both Porsche and Z vacuum solenoids operate on the same principle. When 12V is supply to the vacuum solenoid it allow vacuum to close the flaps. So, here is how you can supply 12V to the vacuum solenoid on the track:

First, find the vacuum solenoid control module which is located behind the right rear wheel well carpet. It has a larger three wires white plug that tells the control module when the engine RPM pass 3500 to open up the exhaust flap to produce couple extra pony by cutting off the power supply (deliver by the single wire from the black plug) to the vacuum solenoid. The smaller black plug with one wire that supply the 12+V to the vacuum solenoid close the exhaust flaps - hence quiet when RPM is less than 3500.



Now, here is the 2.5 seconds come in for the fix. Get yourself a wire, disconnect the two plugs and connect the wire between the red/white wire on the larger white plug with the single wire on the black plug and you will hear the exhaust flaps close (when engine is not running). Why did I chose our fix to be 2.5 seconds when Porsche GT3 takes 3.2 seconds? Well, it's because our car is faster of course

Don't leave the wire plug in all the time or it will drain the battery. I had mine plug in between sessions and no issue with battery running low and the track sessions are some times 1.5 hours apart. As I understand the "man switch" on the market only allows you to open the exhaust flap and not close it all the time. You can always rig up some sort of switch for the vacuum solenoid so you can go quiet when you needed and revert back to stock when you want it loud and more power at over 3500 RPM



So with this simple mod I only got black flag once at 94.8 db but I was going up T5 next to the sound station as hard as I can and track all the way out to the berm which in itself generate much more tire and exhaust noise hence exceed the sound limit by 2.8 db. I got black first session at stock mode without the 2.5 seconds mod. Stock exhaust should have no issue pass sound with this simple mod

Here is a video of the test run at Laguna and couple pictures with my GT3 buddies ... they adopted me whole heartly



Buddy of mine in his blue Porsche spyder send me video of my Z on the track. I made a split screen movie shown below. This Z06 look super stable under hard acceleration and at fast braking zone on T2







wings wings and more wings

Originally Posted by marktsmith

Really enjoyed both videos. Beautiful looking and performing vette. I was impressed at your smooth entrance and exits at the corners, even with all that traffic. Great Job ! I was watching carefully for downshifting. I am having problems with toe/healing in my Z06. It appeared you were in one gear through many corners. Again, thank you for entertaining us with this great performance. Love that blue vette !