2014 Z28 Assault Thread.

[groundnpounder]

I have a hard time believing that GM would knowingly reduce airflow by that much simply so they can have this refreshed style front end. I'm no Camaro or GM fan but I think GM engineers have more brains than that.

Sponsored

 

[Red]

Me too. But, stranger things have happened. Consider the 351C oiling system!

Assuming there is insufficient flow, I'd expect the engineers originally had sufficient flow, but were overruled for one reason or another (happens all the time). But this one would be pretty stupid.

 

[Kingranch]

Me too. But, stranger things have happened. Consider the 351C oiling system!

Assuming there is insufficient flow, I'd expect the engineers originally had sufficient flow, but were overruled for one reason or another (happens all the time). But this one would be pretty stupid.

Yea, what justification could there be to overrule engineers with something as important as airflow. I can understand if bean counters were involved and it was done for profit / cost cutting reasons but I find that extremely unlikely here since extra or larger vents can't possibly cost much more, if at all. I doubt there's much of a difference in airflow in the end.

 

[Norm Peterson]

Suppose that (when you're at speed) getting air TO the radiator is not the critical part of the radiator cooling problem . . .


Norm

 

[thePill]

Suppose that (when you're at speed) getting air TO the radiator is not the critical part of the radiator cooling problem . . .


Norm

As long as there is no AC condenser... The 2012 Boss 302's were removing the grill to help cooling during SCCA events. It is a common problem with '12 Boss's. 2013's were fixed...

Here is a close up of the Z28's fascia. The lower air dam is blocked off about 1/3 of the total area. The upper grill area was reduced by at least 50%... The removal of the AC wasn't really for bringing the Z28 home, it was done from necessity to keep the 5th Gen cooler from the design flaws.

The general feedback from 5th Gen fans is that "We hate it", "It's ugly" and "It's too squashed", "It's dumbed down" ... and they are correct in that assumption and that's just what they say about the front. While Chevy employees race to convince you that the 2014 is better, the poor Z28 has a lot of questions left unanswered. I'm sure they don't really want to get into this design flaw... You just have to see it in person

 

[Norm Peterson]

I'd be willing to bet that most of the gains came from reductions in interference drag and only a little from the increase in net area.


Norm

 

[Red]

Good picture Pill. Blocking off a good part of the lower opening (why? -- bumper?) is not good. I'll more readily agree w/ your original assessment now: the inlet area appears smallish and restrictive. Removing the lattice work from both upper and lower grills will help, but no idea if that would be enough.

Still, back pressure largely determines mass flow through a 'duct' for a given inlet area. W/o seeing the under the hood, and underneath, it's really hard to get a feel for what the back-pressure might be. But, the inlet now looks considerably worse than before.

Unless GM can get enough flow by removing the grill lattice work, say good bye to racing (other than drag). That it doesn't meet the rules is almost beside the point now.

I initially found this amazing, much like KR and groundpounder, but then I recalled my experience w/ a 2500 Silverado w/ the Duramax. Terrific engine, but the rest of the thing was an utter joke. An aspect of that truck pertinent to this idea that GM will hamstring itself: It was a manual trans truck. The clutch slave cylinder would overheat, leak, and lead to the clutch pedal lying on the floor. This happened to me after all of 14k miles of very easy use (mostly highway miles, no towing or hauling -- using the good ole 95 Ford for that). Replaced under warranty. Replacement started to go at around 35k miles (total, so it lasted an amazing 21k miles). Went around w/ the dealer and GM some, when GM asked how I was using the truck. Told them (highway, no towing, hauling, nothing, exceptionally easy use). They countered that the clutch was not intended for such usage. I traded the f'king thing the next week for the F150 I have in my sig. I was dumb-founded. The dealership was good people, no complaints w/ them.

So evidently, the concept of a 'total system' escaped GM, and apparently still does.

One would have thought GM would have done CFD of the entire car, including underhood, so they would know (or have a good idea) the airflow through the radiator, and hence how many HP could be supported. Perhaps they did, but sacrificed cooling for its so-called 'pissed-off' look. Good decision, there -- for Ford and Chrysler.

 

[thePill]

Good picture Pill. Blocking off a good part of the lower opening (why? -- bumper?) is not good. I'll more readily agree w/ your original assessment now: the inlet area appears smallish and restrictive. Removing the lattice work from both upper and lower grills will help, but no idea if that would be enough.

Still, back pressure largely determines mass flow through a 'duct' for a given inlet area. W/o seeing the under the hood, and underneath, it's really hard to get a feel for what the back-pressure might be. But, the inlet now looks considerably worse than before.

Unless GM can get enough flow by removing the grill lattice work, say good bye to racing (other than drag). That it doesn't meet the rules is almost beside the point now.

I initially found this amazing, much like KR and groundpounder, but then I recalled my experience w/ a 2500 Silverado w/ the Duramax. Terrific engine, but the rest of the thing was an utter joke. An aspect of that truck pertinent to this idea that GM will hamstring itself: It was a manual trans truck. The clutch slave cylinder would overheat, leak, and lead to the clutch pedal lying on the floor. This happened to me after all of 14k miles of very easy use (mostly highway miles, no towing or hauling -- using the good ole 95 Ford for that). Replaced under warranty. Replacement started to go at around 35k miles (total, so it lasted an amazing 21k miles). Went around w/ the dealer and GM some, when GM asked how I was using the truck. Told them (highway, no towing, hauling, nothing, exceptionally easy use). They countered that the clutch was not intended for such usage. I traded the f'king thing the next week for the F150 I have in my sig. I was dumb-founded. The dealership was good people, no complaints w/ them.

So evidently, the concept of a 'total system' escaped GM, and apparently still does. Must admit I was unimpressed w/ 'Al' (I think that was his name -- the GM guy in a round-table discussion w/ various mags) in that video Pill posted. Struck me as quite juvenile.

One would have thought GM would have done CFD of the entire car, including underhood, so they would know (or have a good idea) the airflow through the radiator, and hence how many HP could be supported. Perhaps they did, but sacrificed cooling for its so-called 'pissed-off' look. Good decision, there -- for Ford and Chrysler.

The 2014 refresh won't last long. They are in a similar spot Ford was in during the 2010-2013 time frame. The design is bridging the 5th Gen to the 6th however, Chevy isn't working with the same allotted decade the S197 had. This is their 2010, next is a new engine, then a quick refresh on the way out to compete with the new S550. The 6th Gen won't be out until September 2016... Two more model years and the '14 isn't gonna cut it.

 

[groundnpounder]

Camaro is getting another refresh? That would make it 2 refreshes in a 7 year model cycle and those 2 refreshes coming 1-2 years apart? I dunno...

 

[groundnpounder]

Are those halogens on the Z/28?? :doh:

 

[Jarstang]

Camaro is getting another refresh? That would make it 2 refreshes in a 7 year model cycle and those 2 refreshes coming 1-2 years apart? I dunno...

Would really be surprising. 2014 models are just hitting dealers now and word is that the first 6th gen Camaro prototypes will start testing early next year.

 

[OKCfan]

Are those halogens on the Z/28?? :doh:

Track focused car. Guess it doesn't need HIDs

 

[thePill]

As we can see here, the Z28 is absolutely dependant on the AC delete to properly cool even at high speeds. You can see in this Chevy press release, the upper grill barely has any airflow at all. The Z28 should NEVER be optioned with air conditioning. What they are illustrating here is the improved aerodynamics of the Z28 and the obvious reduction in high speed hood lift. The illustration is likely done without the AC condenser present in the lower grill. If AC is optioned, air will not flow as freely through that area and the effects of the Mohawk are likely reduced as well as engine cooling. The upper grill should be completely removed for racing (track).

Some of that air is funneled into the brake ducts as shown on the ZL1 here. That loss in air flow caused severe heat soak in the LSA... This Z28 could also experience high engine bay and intake temps.

I believe the upper grill should just be removed at this point... Very little air flow is allowed in.

Head lights could be changed...

It is difficult to find information on a car the media doesn't care about. If the media doesn't care, I doubt any of the readers will. There are only 4 sources that reported on the 2014 Z28 in the last month... Not the impact the Camaro was looking for. There aren't even bloggers blogging about it really except me and I'm not the ideal media source for that particular product and brand. When the ZL1 convertible was released, there were roughly 40-60 sources writing and reporting on it... The next day the '13 GT500 announced 662/631/200 and 460 sources hit Google news (pretty much the hub for internet news)... The Z28 has had very few, most "interviews" were actually set up by Chevy, not the media. If it wasn't for Motor Trend pulling in all their sister publications, those 4 media sources would only had been one. This is the ugliest Camaro built since 1998 and it is just as large as the new Taurus. We will never get to really see this Z28 in real action, there will always be optimal situations I'm sure and when the 20 fans that wanted one sees how much it is to buy, there will be chaos... Get more media involve Chevy!!!

Buuuuuuuuuut.... We might not want to be so hasty. Is it possible Chevy has realized that their mistake of delaying the Z28 to 2014 MIGHT get it tangled up with a 2015 GT350? What if Ford releases the GT350 in April (a few months after the Z28) and the magazine comparisons start in Spring?

OH S$!&!!!, we just offered up our LS7 Z28 to a $50,000, 525hp, 3400lbs, Flat-Plane'd GT350!!! and the GT350 is legal and sanctioned in the SCCA/FIA/NASA and ready to run in Grand Am/ALMS.

Either release the damn thing so you can at least have a few months of praises... WHO IS MARKETING?!?

 

[OKCfan]

It will be interesting to see how the Z28 holds up in heavy track use then, especially with AC optioned. Good thing it's naturally aspirated or it might have been a limp mode monster.

 

[Red]

Where do you find this stuff, Pill? Nice find.

Some comments for those who might not know what they're looking at.

These are flow visualizations of one or more CFD (aka Computational Fluid Dynamics) solutions. Looks to me, though I can't be sure, to be trajectories of mass-less particles. The pathlines 'appear' to be colored by local velocity magnitude (speed), or Mach number, with red being high speed/Mach and blue being low speed/Mach. I can't be positive of this either, but it is an educated guess.

The flow field is 'seeded' with particles at various user-specified locations for these sort of visualizations. In these pix, the particles were all initially placed far upstream of the car, at a certain height from the ground plane.

The third image appears to have groups of pathlines colored by their seed location.

Note the level of detail in the modelling of all pieces of the vehicle. This is expensive.

A couple points:

1. You can't infer mass flow through the grills from these pix. Had the particles been placed slightly higher from the ground plane, it could well appear that the upper grill would have more flow than shown here. The only way to really tell is to integrate mass flow over both grills.

2. Since radiator cooling is mainly a function of velocity past the cooling fins, and difference between the local air temperature and the local radiator surface temperature, you can't tell how well this car will cool without actually finding the total convective heat transfer from the radiator (which should come out as part of post-processing this solution(s)).

To summarize, while the pix look great (CFD has been called 'Colorized Fluid Dynamics', after all -- at least where I worked in DoD), you really can't tell a great deal of quantitative detail from them.

Nice job by GM (or whoever).

Thanks, Pill.

PS: Hope the above makes some sense -- I'm no writer and I'm rushed right now to boot!

Sponsored