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2014 Z28 Assault Thread.

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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!
Thank you for the explanation, I still highly advise not optioning AC in the Z28.
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Red: thanks for the explanation on those flow diagrams. I think most people think those types of pics represent the amount of air flow.

So do I understand you properly in thinking that the diagrams show 'how' the air flows through and around the car, but now necessarily 'how much'?
 

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Yes, I agree 100% w/ you Pill -- from a common sense/experience perspective. I'd be quite cautious about pushing this car hard for very long. But having said that, can I/we categorically state the thing has cooling problems, based on photos and the CFD images you found? No. I guess that's a point I'm trying to make: Cooling certainly looks suspect, but airflow is a tricky thing.

I agree w/ your synopsis Ricky. The CFD pix simply show the path a massless particle would take. It's a CFD post-processing method meant to emulate various flow viz techniques available in wind tunnel tests, e.g. the smoke traces sometimes seen in various TV ads. Further, one can show the traces as lines (of whatever thickness you want) or ribbons -- ribbons to show the 'twist', 'swirl' of the flow. One of Pill's pictures shows a couple ribbons, I believe.

If one had access to the actual CFD solution files, and is methodical and knows what to do, one could get a feel for the amount of airflow going through the grills by looking at path lines only -- but it's much easier and exact to actually do the various integrations.

The following is meant just for possible forum interest; it is very watered down (I am not a cooling systems/heat transfer engineer).

Convective heat transfer rate is:

dE = Hc*dT

Where dE is the heat/energy transfer rate, Hc is the convective heat transfer coefficient, and dT is the temperature difference between the air/fluid and the heated/cooled surface (the radiator fins in this case). Hc is often found either experimentally or w/ CFD and is usually heavily dependent on the physics of the flow very near the heated/cooled surface -- as in fluid velocity outside the boundary layer over the surface, and whether the boundary layer is turbulent or laminar (or transitional, God forbid). In short, Hc is no where near constant, and can vary greatly from one case to the next.

(For those of you who verify or already know the above, I'm omitting the sign convention for clarity -- obviously heat transferred from the surface is gained by the fluid and vice versa).

In a CFD simulation, we compute heat transfer directly from temperature gradient in the fluid right at the heated/cooled surface and by knowing the coefficient of thermal conductivity of the air at the wall (which can be fairly accurately computed for air at reasonable temperatures). Hc would actually fall out of the simulation, if one wished to compute it. Hc would also vary, in theory, with location on the radiator.

The presence of an AC condenser in front of the radiator hurts cooling two main ways: the temperature difference (dT) is reduced and the speed of the air passing over the radiator is reduced, almost certainly lowering Hc (but not guaranteed!).

Apologies for the long post -- I'm considering deleting most of it, actually, but hopefully at least one person will find it interesting! I'll refrain from now on. I just want to make the point that while the Z28 (or is it Z/28? whatever...) appears to have cooling problems, we cannot state that it, in fact, does, based on the information we have here. Common sense would urge caution pushing this thing hard for long.
 

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No apology necessary. Then again, I've done some thermal transient analysis for piping systems before, so I've got a little idea what's going on here.


There are other questions with respect to the Z/28's A/C, all of which would impact what the coolant radiator sees as cooling airflow.

Do we know if the Z/28's A/C condenser will be oriented as usual?

Will it have the same fin count?

Do we even know that it will be as large as it is in other Camaros?

Why would this system for a low production car have to have the same refrigerating capacity as its large-production cousins?


Norm
 
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Yes, I agree 100% w/ you Pill -- from a common sense/experience perspective. I'd be quite cautious about pushing this car hard for very long. But having said that, can I/we categorically state the thing has cooling problems, based on photos and the CFD images you found? No. I guess that's a point I'm trying to make: Cooling certainly looks suspect, but airflow is a tricky thing.

I agree w/ your synopsis Ricky. The CFD pix simply show the path a massless particle would take. It's a CFD post-processing method meant to emulate various flow viz techniques available in wind tunnel tests, e.g. the smoke traces sometimes seen in various TV ads. Further, one can show the traces as lines (of whatever thickness you want) or ribbons -- ribbons to show the 'twist', 'swirl' of the flow. One of Pill's pictures shows a couple ribbons, I believe.

If one had access to the actual CFD solution files, and is methodical and knows what to do, one could get a feel for the amount of airflow going through the grills by looking at path lines only -- but it's much easier and exact to actually do the various integrations.

The following is meant just for possible forum interest; it is very watered down (I am not a cooling systems/heat transfer engineer).

Convective heat transfer rate is:

dE = Hc*dT

Where dE is the heat/energy transfer rate, Hc is the convective heat transfer coefficient, and dT is the temperature difference between the air/fluid and the heated/cooled surface (the radiator fins in this case). Hc is often found either experimentally or w/ CFD and is usually heavily dependent on the physics of the flow very near the heated/cooled surface -- as in fluid velocity outside the boundary layer over the surface, and whether the boundary layer is turbulent or laminar (or transitional, God forbid). In short, Hc is no where near constant, and can vary greatly from one case to the next.

(For those of you who verify or already know the above, I'm omitting the sign convention for clarity -- obviously heat transferred from the surface is gained by the fluid and vice versa).

In a CFD simulation, we compute heat transfer directly from temperature gradient in the fluid right at the heated/cooled surface and by knowing the coefficient of thermal conductivity of the air at the wall (which can be fairly accurately computed for air at reasonable temperatures). Hc would actually fall out of the simulation, if one wished to compute it. Hc would also vary, in theory, with location on the radiator.

The presence of an AC condenser in front of the radiator hurts cooling two main ways: the temperature difference (dT) is reduced and the speed of the air passing over the radiator is reduced, almost certainly lowering Hc (but not guaranteed!).

Apologies for the long post -- I'm considering deleting most of it, actually, but hopefully at least one person will find it interesting! I'll refrain from now on. I just want to make the point that while the Z28 (or is it Z/28? whatever...) appears to have cooling problems, we cannot state that it, in fact, does, based on the information we have here. Common sense would urge caution pushing this thing hard for long.
Please do not erase, Pictures speak a thousand words but a thousand works speak a thousand words too... Now, we have 2000 spoken words and a better understanding... We would like you to stick around to give some analysis/explanation on any similar S550 studies in the near future. It's just better having more input...
 

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Finally, the tale of two chins.




Nothing new really, Al says it will be "North of $56,500" or more than the ZL1. I can tell you right now, they should have not used the 1LE's TR6060. I believe the maximum torque capacity is 430 but I'm not sure if they upgraded the SS's Tremec or not (Edit: The Z28 is using the MM6 TR6060 and not the SS's M10, Al said it was the 1LE's transmission from the SS) That transmission was engineered along side the LS7, not the M10. Jay took a stab at production numbers saying "Around 1500" and Al said it was correct. They must be building the LS7's before the Z28. I think the QC for the LS7 (hand-built engines) is a bit longer than the usual engines. Although, it was Jay Leno guessing and Al just yeah'd. He could of said 100 or 10,000 and he would have got a "yeah sure". I'm still sticking with the 427 total... Yeah, it's far from 1500 but a hell of a lot closer than the C5 member predicted 4000-10,000 a year.

1500 2014 Z28's in a 1/2 year of production will see pretty decent mark-ups. The Boss 302's and GT500's would see $5000-$20,000 when they came out and there were 4000+ units. The Laguna Seca's were expensive...

Love the GT350 comment from Jay and how much it went up in value... Then goes on to say that he doubt's the Z28 will be a collectors item.

I refuse to comment on Youtube, those guys are being pretty brutal. Some of their comments make mine look friendly... I know a lot of people wouldn't like it but at least say why you don't like it.

Chevy needs to engineer some helmet room into their race cars...





These two are close to 6 foot tall same as me... When I tested the SS in Hawaii, I put the seat back a little to put my helmet on. It didn't really make the visibility any worse but it made me feel like I didn't have confident control of the car. This car is huge in person and the body kit on the Z28 is very, very '80's.
 

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I believe the TR-6060 was rated up to 600 ft-lbf originally. Tremec now makes the Magnum and Magnum XL versions rated up to 700 ft-lbf. Don't know what the MM6 6060 is...

You can see how little I care about this vehicle, or anything GM makes, as I did not know the LS7 was going into the Z/28. Duh... Being dry-sumped could give GM the ability to better cool the oil. So, who knows, maybe it'll live on the track, esp. if they remove all lattice work from the grills, and open up the top 1/3 of the lower grill. I'd really like to know why GM blocked off the upper third of the lower grill.

An aside:

LS7: 7.0 liters, 505 HP (in vette), 72.1 hp/liter
Roadrunner 5.0: 5.0 liters, 444 HP, 88.8 hp/liter

One company is stuck in the past. Reminds me of Chrysler back in the late 70's - early 80's.

Ford could get a nice power increase just by dry-sumping the 5.0 -- wonder if they plan to do so w/ the GT350?

I'll be gone for a while beginning later today (work and such). cya
 
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I believe the TR-6060 was rated up to 600 ft-lbf originally. Tremec now makes the Magnum and Magnum XL versions rated up to 700 ft-lbf. Don't know what the MM6 6060 is...

You can see how little I care about this vehicle, or anything GM makes, as I did not know the LS7 was going into the Z/28. Duh... Being dry-sumped could give GM the ability to better cool the oil. So, who knows, maybe it'll live on the track, esp. if they remove all lattice work from the grills, and open up the top 1/3 of the lower grill. I'd really like to know why GM blocked off the upper third of the lower grill.

An aside:

LS7: 7.0 liters, 505 HP (in vette), 72.1 hp/liter
Roadrunner 5.0: 5.0 liters, 444 HP, 88.8 hp/liter

One company is stuck in the past. Reminds me of Chrysler back in the late 70's - early 80's.

Ford could get a nice power increase just by dry-sumping the 5.0 -- wonder if they plan to do so w/ the GT350?

I'll be gone for a while beginning later today (work and such). cya
The MM6 was initially rated at the exact Z06 level of 470tq, It is advertised now at 500tq but received no modifications from Z06 to 1LE to Z28. Maybe just a re-cert.

I'm not sure if dealers will gouge the MSRP yet or not but, the Stingray is getting a $10-20,000 dollar mark-up. The Stingray has no production limit so... Not looking real awesome for a limited Z28 with exotic parts all over it and an ugly body kit.

http://jalopnik.com/here-come-the-i...ource=jalopnik_facebook&utm_medium=socialflow

Managers at his store have decided on markups half the size of the competition's. He figures the store can please zealous shoppers by helping them be among the nation's first Stingray owners, but at a lower price than rivals are offering.
"If the competition is charging $15,000 above," the manager says, "we'll charge $7,500."
 

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I know you don't care for the Z/28's add-on flare extensions (or whatever they get called). Just that they become necessary when fitting 11" and 11.5" wide wheels and 305 wide tires to a car that maybe had at most 10" and 285's in mind originally. I'd love to fit 11" wide wheels and 285's or maybe 295's on all four corners of my '08, where 9.5's and either 255 or 275 tires fit with room to spare (there's less actual difference than the 20mm suggests) . . . ultimately with either car it comes down to some non-original contours becoming necessary. Pure function winning out even though it's probably an eyesore from a pure design or style point of view.


Norm
 

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Mr. Pill
Thank you for all the effort you put into this forum. I found all your comments most informative, and entertaining.
Can I ask you where you got the listings of the SCCA standings which include the car types as per the following which you posted. I have looked all over for the source of this list, but with no luck.

Quote from The Pill
Let's look at where the Z28 would be if it had a regular brake option, some smaller disc and a bunch of other crap taken off it so it can compete.
 

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Mr. Pill
Thank you for all the effort you put into this forum. I found all your comments most informative, and entertaining.
Can I ask you where you got the listings of the SCCA standings which include the car types as per the following which you posted. I have looked all over for the source of this list, but with no luck.

Quote from The Pill
Let's look at where the Z28 would be if it had a regular brake option, some smaller disc and a bunch of other crap taken off it so it can compete.
Thanks for reading John, I'll provide the link (below) for the current SCCA standings. Just click on the "Current/Updated" link to see all the classes. Hopefully we see you out there in that Fox...


SCCA Point standings... That was a screen shot of the T1 standings about two months ago. I believe the Viper is now in 1st and both Mustang's are in 2nd and 3rd... The Run-Offs are in September so, it's gonna be close... http://www.scca.com/clubracing/content.cfm?cid=45815



It seems the Z06 had issues an dropped out... It also appears both the T1 and T2 Camaro's were pulled from SCCA. Both the 1LE and what ever garbage they threw together for T1 was pulled after the 4th race. (Edit: Both the T1 and T2 Camaro's were the same car and same driver... It was a Chevy sponsored vehicle and dropped out due to a very, very poor showing. The 1LE couldn't break into the top 20 in T2.

If a Mustang can win the Run-Offs this year vs. the Viper and Z06 it will be monumental... That is John Buttermore's class and he won in a Z06 the last two years.



This was discussed on another thread but, it appears Chevrolet has pulled the Camaro from T1 and T2... The T1 and T2 1LE was the same car, neither broke into the top 20 until they dropped out and other people began to drop or wreck out for the season.

Even a z28 that was legal to run in the SCCA wouldn't make an impact any larger than the 1LE...

The 1LE had it's ass handed to it last season in T2, it only took a base 5.0 GT to do it (shown below)



Here is the 1LE in T2 (same car as the T1). 21st place after the 4th (and final) race for the Camaro. It seems Chevy was testing the 1LE out in both classes to see where it stood. In retrospect, it sucked and was clipped from the SCCA after that... I though the 1LE was so much faster than the Boss 302, why it can't manage a GT is beyond me. Media fluff...




What is likely to happen, even though the z28 is super awesome... Chevy will leave the teams and private companies to do all the R&D on the car to make it legal to run... Chevy sanctioned the ZL1 nameplate in GTS (against the Boss 302) but never bothered to build a legal car or try an get the ZL1/z28 sanctioned. They would rather just just the name, skip the engineering and ignore the rules that everybody plays by... Why? Because the z28, 1LE and ZL1 can't compete on this stage. The ZL1 below is the lowest form of participation... NO LSA, No MRC, NO ZL1 braking system...

This is pretty much the z28 here, the only thing that will change is the emblem...




It's difficult for the Z06 and Viper to hold the Boss 302 down, there is just NO Camaro that can, or will be given that kind of performance to do so... The z28 is another magazine wonder.
 

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The MM6 was initially rated at the exact Z06 level of 470tq, It is advertised now at 500tq but received no modifications from Z06 to 1LE to Z28. Maybe just a re-cert.

I'm not sure if dealers will gouge the MSRP yet or not but, the Stingray is getting a $10-20,000 dollar mark-up. The Stingray has no production limit so... Not looking real awesome for a limited Z28 with exotic parts all over it and an ugly body kit.

http://jalopnik.com/here-come-the-i...ource=jalopnik_facebook&utm_medium=socialflow
Not starting any crap but that markup was at one dealer. The guy then went to another and placed an order at 1K less than MSRP IIRC. The dealers that just order a Z/28 to have it on hand will likely mark it up but sold ordered cars will likely have zero.


For every dealer that marks up there is one that wont do it. Sad fact about the crappy dealer network for every maker. I looked at a Genesis Coupe 3.6 Track model when they first came out and the damn Hyundai dealer had a $1500 market adjustment on it. :headbonk:

As far as the T1 and T2 cars, do you have actual proof that Chevy pulled the cars or are you just guessing? Serious question. I want to see the proof or fluff PR piece.
 
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Not starting any crap but that markup was at one dealer. The guy then went to another and placed an order at 1K less than MSRP IIRC. The dealers that just order a Z/28 to have it on hand will likely mark it up but sold ordered cars will likely have zero.


For every dealer that marks up there is one that wont do it. Sad fact about the crappy dealer network for every maker. I looked at a Genesis Coupe 3.6 Track model when they first came out and the damn Hyundai dealer had a $1500 market adjustment on it. :headbonk:

As far as the T1 and T2 cars, do you have actual proof that Chevy pulled the cars or are you just guessing? Serious question. I want to see the proof or fluff PR piece.
That is the only Camaro sanctioned by Chevrolet, it was pulled mid-season last year for some reason... Chevy isn't going to make an announcement stating they sucked the last two seasons and they are pulling support.

Chevy nearly pulled the Camaro out of Grand Am GS in 2011 due to ZERO wins and one 3rd place podium... Driver Matt Bell petitioned Chevy to not pull his ride... Grand Am made adjustments to the rules to help the Camaro (ended up winning 2 in a row) and then Grand Am reversed the rules after 3 races... In which the Camaro was never heard from again until 2012. There was a thread on Camaro5 (gone now) but the Jeff Bucknum "HELP" thread is still up...

Remember now, this move was happening right under Camaro5 members until one of the drivers said something. Unless Chevy intends to peel back support for another chassis (or the new Corvette), they won't issue a statement... They'll just sleaze their way along, leaving the drivers and teams holding the bag. Initially, Chevy was happy Bucknum join Chevy Racing, then they wanted to pull out of GS altogether by June/July 2011.

If Chevy has no momentum in the season, they drop out...

Jeff was contracted in June 2010 by Chevrolet, by July 2011, the Team was out of money due to the pulled support... They sold Jeff Bucknum T-Shirts to raise money...

Matt Bell ditched Chevy and went to Nissan to drive a GTR... I don't know where Buck is racing...
 

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Chevy nearly pulled the Camaro out of Grand Am GS in 2011 due to ZERO wins and one 3rd place podium...
Again?!?! Come on now. Do you just remember the wrong stats all the time?

In 2011, Stevenson Motorsports won races 7 and 8.

2012 they won races 8 and 9.

2013 they have won races 4 and 9.
 

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Thanks for reading John, I'll provide the link (below) for the current SCCA standings. Just click on the "Current/Updated" link to see all the classes. Hopefully we see you out there in that Fox...


SCCA Point standings... That was a screen shot of the T1 standings about two months ago. I believe the Viper is now in 1st and both Mustang's are in 2nd and 3rd... The Run-Offs are in September so, it's gonna be close... http://www.scca.com/clubracing/content.cfm?cid=45815
Thanks Mr. Pill,
It looks like you may have to be a member of SCCA to get into the updates from the above page. I see the "Updated 8/16/13" pointer, but get nothing when I click on it. Probably need to be logged in.

FYI, if you have a keen eye, you just may see me out there in my Fox. It has about 280,000 miles on it, mostly from driving around in your fine country. Been to every state except Hawaii in it.

Any chance you will be joining one of the Pony Drives headed to Charlotte for the 50th? I will be leading one of the caravans through Ontario to Dearborn and on to Mustang OK in April. It's going to be a great party.
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