When Can a Single V6 work well in a Cadillac or a Camaro?

When can a single V6 engine work well in a Cadillac or a Camaro?  When it is as good as the LLT V6.

2010 GM 3.6L V-6 VVT DI (LLT) for Cadillac CTS

What are the features one would need to fit these disparate platforms?  For the Camaro, you might might focus on maximum torque, and maximum peak horsepower.  For the Cadillac, you might focus on noise, vibration, and harshness while delivering maximum power in a fluid manner.  The LLT V6 manages to fulfill both bills with aplomb.

First, the LLT V6 is a 60 degree V-angle engine.  The ideal V angle for balance alone for a 6 cylinder is 120 degrees, to time when opposing cylinders fire and offset the secondary moment.  This is determined by dividing 720 degrees (2 revolutions for a 4-cycle engine) by the number of cylinders.   Due to packaging (width of the engine) and because it results in a very smooth running engine, 60 degrees is generally accepted as the optimal V-angle for a modern V6.

Variable Valve Timing: The LLT uses variable valve timing to optimize its power range.  Dual overhead cam (DOHC) engines such as the LLT have the advantage of different cams for the intake and exhaust.  VVT engines have the further advantage of phasing the input and output camshafts to provide the optimum low rpm Torque and high RPM power.

Cam phasing also pays big dividends in reducing exhaust emissions. By closing the exhaust valves late at appropriate times, the cam phasers create an internal exhaust-gas recirculation system. The 3.6L V-6 VVT DI meets all emissions mandates without complex, weight-increasing emissions control systems such as EGR and air injection reaction (AIR).

Direct Injection is a relatively new technology that directly injects fuel into the combustion chamber at high pressure.  This results in more complete and regulated combustion.  Traditional fuel injection systems inject a fuel air mixture upstream of the intake valve.  Further, the combination of DOHC, VVT, and DI work synergistically to deliver power, fuel economy, and low emissions.

What is next for the LLT V6? This engine family was originally designed to support displacements up to 4L, and to support Supercharging or Turbocharging.   We may see the 3L variant with a power adder instead of the 3.6L  variant, but the 3.6L will always be close to my heart; I have been driving these 3.6L’s in the non-DI LY7 version for six years now and they are very reliable, flexible engines.  With the addition of forced induction they will be even better.

Friday at TMS with Chevrolet #ChevyTMS

Chevrolet was nice enough to invite a friend and I to come out to spend the afternoon Friday at Texas Motor Speedway, then stay for the Rattlesnake 150 ARCA race Friday night.  After a conflict nicely cleared up, my friend Rick Barr was luckily able to join me for the afternoon.

Rick Barr test driving a Chevrolet Camaro

Traffic was light and we arrived early, so we headed over to test drive new Chevrolet models first.  They had a short course setup and you were invited to test drive any of several Chevrolet models, including several Camaros with V6s and V8s in the mix.

I think this is a great low-stress way to expose people to the current Chevrolet models.

Next we checked-in and went on a tour of the tire facility, then the transports and garages behind the scenes at Texas Motor Speedway.

Rick considers which tire to pick for racing

There were stacks of Goodyear tires waiting to be called into action. The race teams lease tires from Goodyear for the weekend. Each tire has an identification chip, so no one can sneak ‘special’ tires in, and none wander off to be resold for another venue.  Goodyear actually tests, in concert with selected Drivers, tires for all of the cars in the series to use at each venue.

Goodyear tire mounting stations

Our next stop was a trip to the race transports. Each transport carries 2 race cars, primary and backup, tools, and spares parts and equipment to assist with repairs, as well as food and snacks for the race teams.

Backup race car stored in the attic of the transport

It was quite interesting seeing what the racing teams travel with and the garages.

Tech Inspection

We also saw the cars undergoing technical inspection.  This was a prime opportunity to see a lot of behind the scenes things that one does not get to see normally when attending the race.  I like all the details and insight on how the teams prepare, technical inspections, and fueling, so it was all interesting to me.

Photo of the author during a lull in the proceedings

After a deluxe dinner of Pizza out of the bed of a couple of Silverado’s, we headed in to the infield drive opportunity.  For this event we each drove a Chevrolet Silverado pickup trucks on the actual Texas Motor Speedway, with one of the Racing Drivers for the evening’s race standing in the bed of each Silverado waving to the crowd.    The truck I drove was brand new, with 2.5 hours of operation time and almost no miles on it before this weekend.

Finally, we attended the Race itself.  The Friday night race was the ARCA Rattlesnake 150.  After we got some ear plugs it was a fun race to watch.  In fact, my number one input for NASCAR would be to consider muffled vehicles, but many perhaps feel that the roar of the cars is an important part of the experience.    Easy enough to bring or buy hearing protection I suppose, but since they have to throttle the cars anyway, why not require mufflers?

Texas Motor Speedway

All in all it was a remarkable day.  I was very glad of the opportunity at the ride & drive for some hands-on seat time in the Camaro, and in the displayed cars some opportunities to examine trunk space and other details.  The behind the scenes tour of the hauler and garages was unique, as was driving a lap of the raceway with a Driver in the bed of the truck.

All of the Chevrolet staff were friendly, nice, and efficient.  The entire day was well planned and coordinated without seeming stressful or strident in the least.  I definitely recommend bringing a guest or a friend to the event, as there were a lot of opportunities for discussion / visiting throughout the day.  One reason I wanted to attend the Friday session was that traffic was light going in and out of the TMS area, and we had no problems whatsoever with the commute there or back.

I would like to see more Cadillacs at this event, but it was very much a Chevrolet Event, and I appreciate them inviting me.  Do we know the lap time for a non-speed limiter equipped Camaro V8 or for the 2010 Cadillac CTS-V at TMS?  Don’t we want to know?

Competition improves the breed Send more LLT V6 HP

Motor Trend did an early test drive and acceleration test on the 2011 Mustang with 3.7L V6 engine, managing a surprising 0-60 time of 5.1 seconds from the base Mustang.  Why does this matter on a Cadillac blog?

The base Mustang competes directly and aggressively with the V6 Chevrolet Camaro.  The current 304 hp V6 Camaro outsells the current Mustang, partially because it out-accelerates the 2010 Mustang V6, which got the old 210 hp 4L engine.  The new hotter base Mustang with the new 3.7L DOHC V6 makes 305 hp, and will ‘put the hurt’ on the current V6 Camaro, if the Mustang consistently manages 0-60 times of around 5.1 sec and the Camaro does the deed in around 6 sec.  Similar hp, but the Camaro is heavier.

To respond, Chevrolet will need to pump up the volume on the LLT DOHC DI V6, perhaps by 40-50 hp to overcome the Camaro’s weight disadvantage.  Generally in this weight class, 10 hp = 0.2 sec difference in 0-60 time.  BTW, another thumb rule in this class is that 100 lbs = 0.1 sec difference.  So the Camaro needs a minimum of another 30 hp, but another 50 hp would be safer.  So that means getting the LLT V6 up to 350 hp.

This is an exciting development for Cadillac because the CTS family shares the LLT V6 with the Chevrolet Camaro.  So hopefully any ponies that GM Powertrain prepares for the Camaro will go right in to the CTS as well.  Doesn’t always work that way, but the current CTS is also coming in high in its class for the acceleration tests, so that makes a good case for sharing.

What can GM do to increase the V6 output?  Tuning the LLT to run up to 7,000 rpm should get it to 325 hp.  Since it is a variable valve timing engine, there is no disadvantage to tuning at the top end.  Work on a more header-like exhaust manifold, and improve the exhaust port flow on the LLT should yield 20-30 hp, which would put the engine at 345-355 hp, with almost no recurring increase in cost for the power train.

Oh sure Bruce — if it is that simple why doesn’t GM do that already?  Because the LLT was meeting the design spec already — a great high value V6 that puts out more than 300 hp smoothly and with great MPG.  But now we need the more, and GM Powertrain needs to turn up the wick and send us a 350 hp LLT.