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TimM Reader
3/1/24 3:02 p.m.

A lap of Nurburg GP track...couldn't quite keep up with the Senna, but I'm ok with that:


TimM Reader
3/14/24 5:47 p.m.

Plugs installed...driver's side takes 20 mins...passenger side takes 2 hours...thanks to dropping the plug socket - Ack!

Bit of oil on #7 threads...otherwise looks a ok.

Also heard a phantom tap on odd side of the engine...so pulled the valve cover and rockers for a look see:

Nothing out of the ordinary - all Ti lash caps present, no broken springs, rocker arm tips are like new, etc.

Will gather the kit for tomorrow's visit to the heart breaker.  Temps are warmer than before (55 degrees) otherwise a constant.  

TimM Reader
3/14/24 6:00 p.m.

I realize I had not linked the 190 mph run done ~3 years ago...I was disappointed with the traffic as this stretch had always been vacant at 0600 on a Sunday morning...  Stock LT1 (with valve springs to counter the boost) and the LT4 blower.  Quite impressive!



Took a bit for the GPS to stabilize, but sync'd with the speedo.  The end of this run also cracked a piston slightly (blew a seal out), but wasn't terminal at this point.  Likely due to at the limit of German 98 octane fuel, 11.5 CR, 11 psi of boost, and when the blower got hot at the end of this run - incurred knock which cracked a ring land.

Rev limiter was set at 6800 rpm...but the engine just wouldn't rev any more.  Hopefully, the new 416 will perform just a little bit better!

84FSP UberDork
3/14/24 6:26 p.m.

Those are big sustained speed numbers and not in a straight line.  Interesting to find the weak links of the powertrain with those speeds and forces.

Datsun240ZGuy MegaDork
3/14/24 7:59 p.m.

That 190mph run was really cool! Every 1980's American teenagers dream - drive the Autobahn.

How fast was that white VW Golf going? 125mph?

Congratulations on your run. 

TimM Reader
3/15/24 7:15 a.m.

Car is extremely solid at speed even with -3 camber up front.  Chevrolet designed a great product. 

The roads are well maintained and this section is a river bottom so about as flat as you can get.  Reverse direction was 189 mph, but I didn't hold it for long.  

VW Golf:  We had just entered the unrestricted zone so he was on the gas quite hard, so 125 was good estimate.  I have to say it is rather rare to see folks exceeding 120 mph on the autobahn in my experience.  I'd guess the Germans are used to it (lack of novelty) and the fuel mileage is atrocious at speed ($8 gallon cost!).  

onemanarmy Reader
3/15/24 8:44 a.m.

Liking this thread!    Awesome to see a Camaro used as it should, instead of terrorizing residential neighborhoods with the V6 and going 70mph on the donut spare in a 25mph zone.

Is there a factory gearset swap that would get you the top speed?

TimM Reader
3/16/24 1:16 p.m.

onemanarmy:  laugh  I'm not aware of another gearset available.  It seems we have moved away from interchangeability - the rear diff in this car is electronically controlled which seems to limit V8 Camaros to a standard 3.42 axle.  Honestly, I think it is the best ratio with the 6 speed equipped car - I just need the engine to rev higher - 6800 rpm should not be an issue.  Just 250 rpm more than before!

Dyno visit was successful!  The stars aligned, dyno was operational (mostly) and tuner in Connecticut was online to tweak after each run. 

Strapped down and prepped:

We did 6 runs and 5 'flashes' of the ECU...gaining just shy of 50 CHP for a grand total of 700 crank horsepower.  Dyno sheet between untuned WOT and yesterday's best run:

Pleased with the output.  The dyno was acting up with a cooling fan failure and anomalies appearing in the curves.  The tuner was confident the engine was not to blame and enough runs were made to ensure a smooth power curve.  The torque number is inaccurate due to the spike.  I have no idea what 966 NM is anyway...!

I self limit the combination due to the OEM sized blower (1.7 liter vice aftermarket of ~3 liter) and the stock exhaust manifolds/cats.  Updating those would release 150 - 300 CHP, but not needed/desired.  On the track, I'm barely able to handle the original 455 HP!  Nor would the car pass German visual acceptance.  Cars get confiscated over here if modifications are not 'TUV' approved.  Americans do get more leniency, but I'm not pushing it past my cold air intake...

I will say on the way home-4th gear it really pulls nicely to the 7100 rpm limiter (150 mph)...

May be tested on the Nurburgring tomorrow (opening weekend for the season!).

67LS1 Reader
3/17/24 10:44 a.m.

I think at those speeds, aero is not your friend. Could you do temp mods just for your early Sunday autobahn runs or when running at the ring? 

TimM Reader
3/17/24 3:36 p.m.

67LS1:  I'd prefer to keep it 'as driven' :-)  Nonetheless, what changes would you recommend?

Great news!  Made it to the Nurburgring today - nearly perfect.  The 0415 wake up to arrive at 0800 paid off - 40-45 degree temps / 2nd car on track / no moisture! 

Admittedly, I'm quite rusty and the chilly temps along with few oil spills from yesterday made it 'super' exciting!  Very happy with its performance although still working thru a throttle response issue.  Wonderful electronic throttle actuations...

The exhaust note and now supercharger whine feels like you really did something when you step on the 'loud' pedal.  The acceleration is something that will take some time to get used to (if ever).  The circuit is full of lumps and this car now spins the tires more readily...I'm quite impressed and a bit freaked out!  I soaked my sweatshirt even with max ventilation energized.

I did incur an engine miss on the return to homebase portion, so still trying to figure that out, but doesn't appear to be mechanical.

A simple video...the second half was a bit more exciting as I was becoming a bit more comfortable - 5 laps complete (65 miles):


Really amazing products we have now days - brakes/tires/suspension makes one feel like a real race car driver and still get 19 mpg at 100 mph to and fro!  And that exhaust note!

TimM Reader
3/20/24 5:25 p.m.

Did get a bit of air on that particular lap:

Real nice shots the track photographers take!

TimM Reader
3/22/24 6:12 p.m.

I drained the Mighty Mouse oil separator after 1000 miles:

Bit more than I expected, but 6 dyno runs, 65 track miles, and several accels on the street - possibly ok.  We'll monitor it...

It also appears the throttle body maybe failing with inconsistent throttle response, trailer hitching and most recently flat out missing on cruise/idle - intermittently.  I had purchased this Nick Williams 103 MM TB (work of art!) over 3 years ago wasn't expecting a warranty, but they offered to ops check it and replace the innards if required.  Possibly, they received a bad batch of the internals...

Removal was easy:

And already boxed and shipped out:

Love the blower shot with the Kong porting!:

The unfortunate part is the car is sidelined for couple of weeks...missing my purchased in advance Spa F1 trackday!  Costs are not insignificant overseas...nearly $1000!  I will be employing our 'back up' car (Evo 5) to see if it gets us home...(10 hour round trip).

TimM Reader
4/3/24 3:53 p.m.

Track day in the Evo was a ton of fun.  Would have been much better in the bigger HP car (Camaro!).

Did receive a new near exact replacement for the TB...this time from Katech.  Work of art!:

TimM Reader
5/14/24 2:14 p.m.

Katech 103 MM throttle body did the trick...car runs like previous.  Also received the Nick Williams back with fresh electronics - now 100%.  Expensive repair, but simple to fix!

Fast forward a month...car was ready for an autobahn run.  

Oil changed, full tank of 98 octane (93 US), and tires pumped to 42 psi cold...headed out at 0500 Sunday morning for the hour drive to an optimum location - river bottom, concrete and a long, unrestricted straight without on ramps:

Not the goal of 200 mph, but it did survive 2+ miles at WOT and drove home so can't complain.  6 mph increase from previous.

There are still issues - end of the run had a catch can overflow which moistened the engine a bit to the point of coming out the hood vent!  Admittedly, I failed to drain the catch can before the run, but it had only been 700 miles...possibly an issue.  I did pull the plugs following the run and all looked happy.  Also did a cranking compression test:  190-198 even across all 8 cylinders.

Boost:  Also noticed the boost dropped after 1.5 miles - lost 2 psi, 11 psi to 9.  That could be ~25 CHP loss right when it needed it.  This is OEM pulley sizing.

Alignment:  Car has -3 degrees camber on the front - possibly not ideal, but I'm more concerned in the toe - noticed a bit of extreme inside tire wear which is not normal even with this camber.  I also noticed the car wandered more than previously...this could be extra rolling drag.

Brake cooling:  I had recently installed the several times larger cooling ducts from a Cadillac...they definitely hang down far more than the OEM's...might help to pull them off next time.  Surely the underside of the car has minimal impacts?

The acceleration in 4th is very impressive and 5th is nearly so especially considering the 'long' gearing.  

I guess the project is not complete!  More to follow...:-)

nsogiba Reader
5/15/24 8:46 a.m.

What a fun problem to have!

Perhaps you can pick up a few more MPH on the top end by going with a taller rear tire, which would change the effective gear ratio?

I also wonder if the engine is pulling ignition timing after a very long pull due to higher IAT.

golfduke Dork
5/15/24 9:59 a.m.

Impressive! Andan Evo 5 is certainly not the worst 'backup track car' I could think of!  :p

TimM Reader
5/16/24 4:54 p.m.

nsogiba:  Yes, the LT4 blower was running warm and caused 2 degrees of ignition timing retard.  Only getting 17.5 degrees which is an impact, but inevitable for a 2 mile accel.  Even the coolant was hitting 228.  A cooler day would help on both counts and/or pull the significant Euro plate of the front!  I hadn't thought of a taller tire and surprisingly seems to be available.  However, this car is primarily to perform on the road course (and street) and reducing the gearing isn't my preference...might even get some chassis computer lights.  Would rather optimize the engine...we still have room for improvement.  laugh

golfduke:  Completely agree - we are car rich for someone who nearly made good with a Honda Jazz for the overseas tour!  Evo 5 definitely needed more oomph to keep up with the Ferrari's.  Ha.

I contacted the supercharger porter and he now offers an Stage X port!  Supposedly, geared toward topend power...theoretically a gain of 60 WHP over my current combination.  I think optimistic especially considering I'm running an OEM exhaust to include full cats and manifolds (which neck down to 2.50 inches!).

Possibly without belt slip (2 psi loss) and an X port...we might be there.  That may wait until winter to ship the blower off to the states and the 6 week down time.

For now, happy to set a new personal record and still 20+ mpg.  Amazing Chevy product.

nsogiba Reader
5/17/24 7:47 a.m.

Since the 2010s GM has done an incredible job making supercar like performance available to the average Joe for a reasonable price. Even their interiors and build quality has caught up. 

TimM Reader
5/18/24 4:23 p.m.

nsogiba:  couldn't agree more.  First track day with my 1996 Corvette LT4 (330 HP) and it popped a water pump...next was a power steering line...giving up the ghost 2 more times after that!  Then wheel bearings, then cracked manifolds,...took some time to make it track worthy!

This car came with a warranty for the track (until you modify it!)...impressive progress.

Drained the oil to see any metal...clean!  Looks like the 416 is ready for more.  :-)

TimM Reader
5/26/24 3:56 a.m.

Came across a simple, neat reliability upgrade - plastic coolant thermostat shield.  Folks have lost blower belts which then whip around and break off the small plastic barb on the thermostat housing - thereby losing coolant.

Seems like a good idea with the higher rpm I'm spinning the blower (OEM ratio, but 500 rpm past factory redline).


After - couldn't be easier - slip on and use OEM nuts to secure:

Scheduled for an alignment adjustment due to the excessive toe on the front and will decrease the negative camber from negative 3 to 2.5 degrees.  I find the car a bit wonky at that camber at the higher straightline speeds.  Hopefully the toe will reduce drag as well.


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