MotorTrend Pits the ZL1 vs GT500 on the Street, Dragstrip, and Racetrack

[Stew]

Originally Posted by 2012ZL1

No we have to wait to compare the 2014 ZL1 to the 2013 GT500 to be fair. I hear the GT500 is getting an upgrade to turbo 4 cyl.

But by the time the 14 ZL1 gets out of quality control the 15 GT500 will probably be out, sorry, I couldn't resist....

[evolve]

Originally Posted by Angrybird 12

Thanks for the explanation.

Glad he clarified this. He is absolutly correct too (about the strip part).

[ParisTNDude]

Originally Posted by HumanWiki

I see the point, but what, do tell, is the performance difference between a 2012 ZL1 and 2013 ZL1?

Kinda confused by your question. I don't think there will be a single bit of difference between the 2012 and 2013 ZLs...I'm asking to see a head to head comparo of a 2012 ZL and a 2012 GT500.....certainly a much more fair comparison.

[Stew]

Originally Posted by ParisTNDude

Kinda confused by your question. I don't think there will be a single bit of difference between the 2012 and 2013 ZLs...I'm asking to see a head to head comparo of a 2012 ZL and a 2012 GT500.....certainly a much more fair comparison.

It is mainly a matter of why do we wnt to see GMs greatest against a car Ford stopped building months ago? Even though the model years are different the current comparisons ARE the most fair becuase both the 12 ZL1 and 13 GT500 both actuall hit the streets at roughly the same time. I personally would love thee a 12 GT500 vs ZL1 comparison, but it doesn't make sense now.....

[ParisTNDude]

Originally Posted by Stew

It is mainly a matter of why do we wnt to see GMs greatest against a car Ford stopped building months ago? Even though the model years are different the current comparisons ARE the most fair becuase both the 12 ZL1 and 13 GT500 both actuall hit the streets at roughly the same time. I personally would love thee a 12 GT500 vs ZL1 comparison, but it doesn't make sense now.....

Just that the 2012 ZL was aimed at the performance level of the 2011/12 GT500 and as such would compete very well with that car. I would consider the GT500 for myself but think it will lose a lot of value when the IRS suspended Mustang arrives. I am eceedingly proud of the performance level of the ZL and the GT500....European car manufacturers will certainly need to "upgrade" to keep up with these two monsters!

[Stew]

Originally Posted by ParisTNDude

Just that the 2012 ZL was aimed at the performance level of the 2011/12 GT500 and as such would compete very well with that car. I would consider the GT500 for myself but think it will lose a lot of value when the IRS suspended Mustang arrives. I am eceedingly proud of the performance level of the ZL and the GT500....European car manufacturers will certainly need to "upgrade" to keep up with these two monsters!

Agreed that I think it would be a good and fun comparison, but you can't hold it against Ford that they upgraded the GT500 and force them to put their now obsolete car against the competition.

[tt335ci03cobra]

Only read the following if your interested in turbo tech and how it compares to sc tech on the road and race track. I also went into longevity and efficiency. Hope this helps anybody with questions. Cheers. Please correct me if I have any inconsistencies or mistake, good knowledge always evolves.


Turbo's do run off of hot exhaust but because the boosted air then runs through a very efficient intercooler, inlet air temps can drop down decidedly compared with an sc car.

On my old afco heat exchanged, cold air inlet, 14psi eaton setup, I made just 470/490 whp/tq corrected (410/425 uncorrected) but had inlet air temps as high as 150 degrees after about 5-10 minutes of canyon carving. Literally, I could feel about 50-100hp taking a nap when it got hot. This was on mild 70-80 degree days with little humidity but we are at 4400ft of altitude. This was also on a 4.6L not my bigger, hotter 5.4 I run now.

After going 5.4 and twin 57's, but with a very efficient dual in dual out intercooler, and aftermarket coolant reservoir with larger lines, my iat's just hover around 65* and maybe hit 75* if I've been wot in it for over 10 straight seconds. This is on my 15psi 885whp tune and you can imagine they're aren't many places to stay I it that long, not on any canyon especially.

I can pace along and carve a canyon side by side with my buddy's z06's and not fall victim to heat soak now at all. We crest 5 miles And 2500ft of elevation gain and my iats are still in the 65* range, really safe tune as well. It's actually odd, but my turbo's a run a little better when my motor is around 195* instead of the 175* my motor used to love supercharged; that's because the extra temp helps spool the turbos faster.

I think these are the major reasons n/a and more so turbo cars are used for track work. Gas mileage also plays in too. If I lug around in low gears around 15-2000rpms, I can knock down highway mileage easily into the mid 23-27mpg range, even with a 5.4 and 900hp. The reason is we were able to lean out the fuel tables from 15-2000rpms since the turbos can only make about 4psi in that range. If I step on it at freeway speeds in 6ths, I still have about 450wtq at those speeds, but at 2500 I have near 700wtq. Turbos aren't as efficient at making power at 2000rpms as an sc, but there's still enough power not to inhibit the flow of traffic; 450wtq in 3400lbs more than moves it along.

Sc's make more power down low but because of this, they're fuel tables must be richer at lower rpms to avoid detonation as boost can be as high as 9-12psi when you are pullied for a max of 15-18psi higher in the rev range. Factor too though that roots blowers and smaller blowers will need even richer fuel tables since they can create boost quicker and faster than larger twin screws and lyshoms.

It's odd to believe, but an ss camaro with a 2.1L roots blower making just 550whp will likely get worst gas mileage at freeway speeds than an ss with a 4.0L whipple. Less boost efficiency at low rpms means the tuner can lean out the tune at low rpms, however this is all assuming the same boost is pulled for each, say 18psi. Now if the whipple is pullied for 30psi, then it has the potential to make more boost at lower rpm vs the roots blower just because of the ratio of rpms on the pullies. This would have to be addressed by the tuner and accordingly have fuel added in the lower rpm fuel tables to keep it safe.

Another reason turbos are popular for racing is durability, sc setups offer more instantaneous torque on throttle tip in but they do this by using power from the engine to spin the lobes. This parasitic drag results in instant power but also is stressful on the engine as it is using anywhere from 5-25% of the engines power and sometimes more so to spin the blower depending on the rpm and boost.

This also means there is a constant drag which limits the gains of the additional boost. When this happens, you also begin to take in additional wear as the motor is technically working at a pace of say 800hp, even though it's only producing say 600hp. This means there is an inefficiency that requires a big amount of work load to generate the600hp. This is still more power than it makes na, which we can assume is 425hp, but this same boost level that made 600hp with a blower at about 15psi could be had with just 7-9psi with turbos. This turbo motor is also much less stressed because it isn't actually working at 800hp with drag, it's literally just making about 615hp with 1-5% of the na motors power or rather exhaust scavenging and efficiency being used to spin the turbo(s). This really comes into play when you run high boost. A 1,000hp sc car running 30psi is probably operating at a stress load of about 1250hp. A turbo car at the same boost is only working at a load of about 1010-1050hp. That's a huge difference and obviously allows for more durability.

Lastly, sc boost is simply a pushing force. It's not a balanced force so in essence it will wear out the heads an piston tops while stressing the rods and possibly the crank. A pushing force is best exerted when it can be balanced by a simultaneous pulling force so as to cradle the internals. Turbos can do this as they initially pull; which is why you feel such a draw of torque in a turbo car at low rpms, then can also beginning pushing in boost around 2500rpms once boost is fully spooled. It's a cradling of the internals with push/pull vs push only with minimal additional exhaust scavenging. This generates much less stress on the internals and bodes very well for longevity. Also, less boost is needed to make the same whp so it's easy to see why 8psi of cradled pressure is much safer than 15psi of pushing pressure.

A little boost building time is needed from 1500-2500rpms but honestly no race is run at those rpms, and launching a car with a $200 2step is enough to have boost and launch with 8psi. I launh my car with 4psi and my first goes to 65, I can spin all of first if I launch above 4,000rpms. Plenty of power to avoid the proverbial bog from turbo setups of yesterday. 2steps are pretty much exactly what the zl1 and gt500 use now as launch control and Chevy had one built into the ss cobalt so it's easy to assume the manufactures could put them into setups with factory turbo mills.

Anyways, hope that helps to explain some of the reasons turbo's work as they do. There's a lot of tech and dynamic that I didn't cover like efficiency curves, volumetric efficiency, etc but in general just realize bigger volumes of air need more time to spool and are harsher than smaller volumes of air. They also have different heat dynamics as a larger volume heats or cools more slowly-thermal dynamics always apply.

In closing, these reasons are why I really hope they switch to twin turbo mills for the next generation gt500's and zl1's. Its also true that peak power will span longer rpms; say from about 5500-7000rpms for the gt500 and 5000-6250 for the zl1. Average hp would be up so much that even if they dropped peak hp to 550 for the z and 620 for the gt500, their acceleration would actually be better all but above 150mph where peak hp will matter as your at that point for longer an longer stints of time per gear.

Lastly, a simple boost controller and tune means 200hp. $700 in mods for 200 relatively safe hp just by going from 8psi to 15psi? Yes please and thanks.

[tt335ci03cobra]

2012 gt500 vs 2012 zl1 would be a good comparison to see, let's find members with each and see if they are willing to hit the strip, canyon and track. So long as both have full coverage and aren't foolish on the canyon, they could even swap cars for the canyon run. 7/10th pace obviously, no need to actually have to call aaa

[spratleyea]

Originally Posted by mdmoore23

Is anyone surprised about the GT500 posting faster lap times in the past few tests? It may need some brake ducts or different pads though.

The GT500 has a horsepower advantage and it's lighter weight.

[DanSS24]

Originally Posted by Fenderaddict2

Is this still going on?!?! Tie. It's a tie. Both kick arse cars. It's a tie, get on with your lives already...

I feel for you...don't waste your breath with this thread...it just got sad.

[stymie]

solution: THE INTERCOOLED TURBO-SUPERCHARGER!

http://rwebs.net/avhistory/opsman/geturbo/geturbo.htm

[PQ]

Turbo vs Supercharger had been discussed and learned ad nauseam. Claims have been made on both sides.

I'll never be convinced one is any better than the other. Any more than I'll be convinced that Basketball is better than Baseball.

They have their uses.

[tt335ci03cobra]

Originally Posted by PQ

Turbo vs Supercharger had been discussed and learned ad nauseam. Claims have been made on both sides.

I'll never be convinced one is any better than the other. Any more than I'll be convinced that Basketball is better than Baseball.

They have their uses.

To each there own, I also didn't cover gains at altitude but ya, for any application at 2000ft or higher, sc all the way of you want to get the claimed hp gains. Up here my uncorrected numbers are higher than my buddies sc'd corrected numbers at higher boost. He's got a Kenne bell making 720whp corrected. I raced him on 13psi with 730 uncorrected and it was really ugly. I dropped down to 10psi and was still faster. He is pullied for 20psi and runs meth.

At sea level his car will be a lot faster, as it sits here in slc he runs 10.90's at 130. He has around 620 uncorrected whp

His car gets a little hot, but not as bad as some. We've done freeway pulls in 4th gear around 70 and I still start to pull immediately. He has 3.73's and I had 3.55's when we did this also I had 28" tires and he had 26" tires. I was probably 500rpm lower than he was when we did this race.

I've been 110% convinced on turbos but thats because where I live there isn't an alternative because of thin air if you want to run 9's. It takes tons of boost with race gas, supporting mods, and chassis work to get an sc cobra or ss camaro to run 9's up here, but my car is capable of it on a pump gas tune. To put it in perspective, stock ss Camaro's and 5.0 2011 mustangs hardly break 14.0's up at here at more than 105.

My 03 cobra ran 13.6@106 with a 10psi pulley and cold air kit with mufflers. That same night my buddy's c55 amg ran 14.2's at 100. Those cars both run about 13.2@108 and 12.7@114 at sea level.

My buddies stock Evo 8 ran 13.9@100 but does get pulled by ss's and 5.0's on freeway pulls, and my buddies 265awhp wrx ran 13.7@103. Turbo cars run a lot better up here because turbos compensate for the thinner air by spinning faster and flowing more of it to keep o2 counts as they should be. It's like 17psi of crappy air but it is a legitimate 14.7psi of dense sea level air because it measures o2 counts. 65,000rpm impeller speeds because the air is thinner and creates less resistance. At sea level that same density of air only needs about 56,000rpms of impeller speed. Both figures are guesstimating but it is the case regardless of speed or pressure that they compensate for air density because of this tech/mechanical setup.

[PQ]

I went PD because it's just more fun to me. Instant big TQ.

The cost DID have to do with it too and I could do the work myself.