[waterman]

Good stuff! Nice driving. Thanks for posting, following.

That's the first Camaro that I've seen on the GP circuit.

Both Nordschleife and GP are on my bucket list. Obviously, if I ever make it there I'll have to rent. Some pretty sexy P cars are available at a reasonable price.

Until then I'll drive there vicariously through you.

[Tim M]

waterman: Thanks for the comments. The GP track is one that I could enjoy doing more laps on.

Took a bit of down-time to freshen the rear brakes - 23,000 miles is not too bad (and 850 easy circuit miles). OEM replacements installed with some RB 600 fluid. Had a bit of help from an assistant too.

Parts:



Pad Part number:



Not so free help:



Old:



Inwork:



New:



Incredibly easy install - modern brake system...added some fresh fluid:

[Tim M]

Had an invite to do a Friday evening at the Ring (2:15 duration)...so gave it a go.

Traffic on the autobahn was heavy as expected with 2 incidents re-routing me off the path adding nearly 60 minutes to the 3+15 trip. Arrived 30 mins into the session...short durations are risky as I drive 6 hours round trip for such a short window...and if the track is fouled...

Nonetheless, got 5 laps in with lower than average traffic - with a new personal best of 7:44 bridge to gantry with a bit of traffic.

Previous was 7:50...with more time to drop. Much more comfortable with the car - an amazing tool Chevrolet has offered.

External video of a few shots - 0:54, 7:13, and 11:38. The first pass was the best with a bit of black marks laid down.



Can't describe the thrill the ring is for heart pounding adrenaline rush. The altitude is just hard to describe. With the quicker pace brought the car jumping solidly 3 times and rpm spikes another 2 as the rear tires leave the ground...in 5th gear!

My confidence continues to build on learning the lines of the track. I'm most deficient on the very high speed sections - 140+ with blind corners...for good reason. This is where most of the time will be found as well.

I need to correct the throttle sensitivity - the supercharged power comes on in a huge hit that is a real challenge to control on corner exit - I've yet to try removing traction control for that reason. I still get significant oversteer - great fun, but not optimal.

The rear brakes worked as advertised and the return trip in the evening was relaxing at 125 mph!

[waterman]

Good stuff!

Great improvement given your trials getting there and the traffic on Nordschleife. Congrats!

[Gary H]

That's an awesome time!
I'm hoping to get out at the end of September

[Tim M]

The video - a bit more action in this one :-):



Not proud of a lapse in concentration toward the end of the lap...off line and paid for it. Even with that and a bit of traffic - happy with a 7:44.

Many lines are still poor - you'd think I'd be further along after 50 odd laps. The speeds you hit on this 'single track' is only similar to my laps at Daytona...and there you can see for miles, 3 cars wide!

The LT4 blower is quite the upgrade and the LT1 seems to be holding tight - I have pulled back most of my shifts to 6000 limits. I've got a set of valve springs awaiting installation.

[Tim M]

Received my order from BTR and Chevrolet to do comparisons on valve springs:

OEM LT1/LT4 spring and shim-seal combination vs BTR spring, locator, and seal:



Using 1.9 inch installed height, interestingly both springs yield same pressures!





Over the nose of the intake lobe:

OEM - 304
BTR - 300

Over the nose of the exhaust lobe:

OEM - 290
BTR - 290

However, the BTR is able to accommodate shimming due to a better coil bind height.

I'm unsure if the 1.9 installed height includes the locator or shim/seal (reduced installed height).

I may have to wait until I pull it apart. Nonetheless, adding a shim will bump the pressures likely into the desired range.

[Tim M]

Had a chance to investigate this LT1.

Driverside valve cover access:



Never been touched and it is missing a valve cover bolt - odd:



Quite the valve cover baffling:



Blue Grass tool...works pretty good:



Springs are quite pretty:



BTR's installed:



I spent time measuring both the installed height and pressures related. Using my not exactly the best tools (spring micrometer did not fit the narrow LT1 spring pocket...defaulted to a metal ruler and 14 year old eyes.

With the OEM spring seat/seal combo - installed height is 1.9375 inches.

OEM spring seat pressure: 94
Over nose of intake lobe: 304
Over nose of exhaust lobe: 294

BTR's setup includes a thicker spring locator and the valve locks are .050 lower - decreasing the installed height to 1.8875.

BTR spring seat pressure: 124
Over nose of intake clobe: 328
Over nose of exhaust lobe: 324

I elected to include a .015 shim under the intake spring...bumping pressure a touch to fully offset the ~11 psi boost:

BTR with .015 spring seat pressure: 128
Over nose of intake lobe: 342

Hopefully the other 14 springs replace as easily.

Note: putting the engine at TDC only allows the valves to drop quarter of inch or so (more on the exhaust side). No air or rope trick required.

Desire is to return to 6500 shift points and possibly 6800 when required.

[Boost Creep]

New pushrods?
They were a standard mod on the LS engines, stiffer pushrods to eliminate deflection.

Don't know if they have been upgraded when the LT1 was designed.

[Tim M]

Originally Posted by Boost Creep

New pushrods?
They were a standard mod on the LS engines, stiffer pushrods to eliminate deflection.

Don't know if they have been upgraded when the LT1 was designed.

Boost Creep: I hadn't given it any thought at this point. I could see new parts at the next step, but this time just the bare minimum - springs (locks/seals).

Down the road, the lifters will get replaced, but will expect to remain with the OEM cam/rockers.

Thanks for the suggestion.

[Boost Creep]

Originally Posted by Tim M

Boost Creep: I hadn't given it any thought at this point. I could see new parts at the next step, but this time just the bare minimum - springs (locks/seals).

Down the road, the lifters will get replaced, but will expect to remain with the OEM cam/rockers.

Thanks for the suggestion.

Just thought I'd plant the seed for more mods.


Like I said, in the LS the pushrods were kind of a weak point, but I haven't done any research on the LT1 and if the same pushrods are used.
Might as well wait until lifters anyway.
I hear my lifters from time to time, figure when warranty is over they will fail then time for maybe Johnson lifters?
I really need to do some reading up on whats current.

LS7 lifters were the go to at one time, don't know if that's true anymore.




Lifters can get expensive since you might as well do heads once they are off, or at least get the stockers ported.
While the heads are off, the cam is right there.....

[Tim M]

Your defining mission creep, boost!

I have no plan to change the cam - I enjoy the smooth idle and clean exhaust.

The other parts...I've considered.

Well, down to the last cylinder for the spring change and ended up with this image...what is missing?



Fortunately, I had eyes on when it flipped off the retainer...fell externally to the engine into the bowels of the engine compartment. So waiting for a replacement...bought 2 weeks of downtime. It was newbie mistake...not employing any catch rags.

[SSDan]

Originally Posted by Tim M

Well, down to the last cylinder for the spring change and ended up with this image...what is missing?

Fortunately, I had eyes on when it flipped off the retainer...fell externally to the engine into the bowels of the engine compartment.

You are lucky! On my last Camaro the performance shop that did the cam upgrade let one of the valve spring locks get loose when pulling the original valve springs. They didn't find it nor did they tell me about it. I found it sticking to my magnetic oil pan plug when I did the first oil change.

Luckily no damage was done as the little thing made its passage through the engine's innards on its way to the oil pan.

Good luck! Sorry you have the down time.

[Boost Creep]

I use a couple magnets while doing spring keepers to try and catch any escapees.

lol
I love the sound of a nice cam, but like you I enjoy decent fuel mileage, and road manners that can sometimes take a hit with a cam swap.

Cylinder heads are a win as long as you don't go for a giant set of top fuel race heads.
Decent port job will add power throughout the rpm range.