Godzilla gets bitten - MotorTrend does a do-over on the 2015 Chevrolet C7 Z06 vs. 2015 Nissan GT-R Nismo Edition (and they throw in a an 8L90 automatic Z06)

[Sticky]

Remember last month when the 2015 Nissan GT-R Nismo edition spanked the brand new 2015 Chevrolet Corvette Z06 around the Big Willow Springs roadcourse? It was not even close despite the Z06 pulling more on the skidpad, having more power, more torque, weighing less, and offering better braking.

It certainly made everyone scratch their heads as the result did not make sense based on the specifications as well as the performance figures recorded by MotorTrend themselves. Every aspect on paper favors the Z06. Yet the GTR has two big aces up its sleeve with all wheel drive and its dual clutch transmission. Not to mention despite the power, torque, and weight not being in the GTR's favor it accelerates faster.

So what gives? What happened? The rear suspension was significantly out of alignment. Yep, that's all it took to skew the results.

Here, Motortrend explains it:

It was supposed to be running 0 degrees of rear caster. Instead, it was running positive 2 degrees. This made the rear dampers less effective at controlling the rear suspension and as a result made it more difficult for the Z06 to put power down. This is exactly what Randy Pobst complained about during our test.

The Z06 suspension allows you to tweak basically everything for track duty including the rear caster. Does it make a difference? How about a 2.1 second difference around Big Willow? From 1:27.10 to 1.25.00. That's huge. That is night and day. It also puts the Z06 ahead of the GTR as its specs already told us it should be.

Part of the problem as well is that Big Willow is not as forgiving as other tracks. Chevrolet intends to offer a mode now softens the dampers in a Rough Track Mode. That says a lot about Big Willow. It also says a low about how Chevrolet engineers are not sweeping this under the rug but fixing the car's teething issues. Ferrari they are not.

What about another big point? Well, it was suggested that the manual transmission was part of the problem. Automatic Z06's were scarce last month and they still are but MotorTrend did get one to test. It somehow put up a slower lap than the manual car at 1:25.76. This may be due to the gear ratios in the manual favoring a track like Big Willow.

There is still a problem with this do-over if you will. The GT-R did not get another shot
and Nissan was not allowed to look over its car and send it in again. Additionally, this was not done on the same day in the exact same conditions.

So, there are flaws here and we will have to wait for more data. We have a long way to go before the dust settles.

[richpike]

Much, much better. Something just didn't feel right on that first test. The data didn't lie, but it just didn't make sense. This makes much more sense. But now I'm surprised the 8L90 didn't post a better time.

-Rich

[Sticky]

Ya but who knows what the hell else they did to the car. Now this is all f'd.

Nissan could do some revisions to prep their car for Big Willow too I bet.

A big ass company like GM doesn't have the car dialed in to begin with? How about just checked for basic maintenance? That big of an issue isn't spotted?

Maybe there is something to be said for Ferrari's paranoid OCD but Chevy blew this.

[BlackJetE90OC]

The first test Nissan provided octane booster for the GTR. While the Z06 ran around all day with 91 octane.

[Sticky]

The first test Nissan provided octane booster for the GTR. While the Z06 ran around all day with 91 octane.

The plot thickens.

[Sticky]

$#@!ing Vbulletin still can't get quotes in quote tags to display on CMS pages, unbelievable.

[onisyndicate]

Viper ta ftw.

[Sticky]

Viper ta ftw.

Loving the Viper more and more every day.

[ND75R]

The first test Nissan provided octane booster for the GTR. While the Z06 ran around all day with 91 octane.

I've seen this argument before and it seems totally irrelevant to me. The Nismo says on it that it requires 93 octane. The Z06 requires 91 octane. They ran the octane each car needed.... I'm doubtful the Z06 would pick up more than ~10 HP / ~10 lb-ft if it was ran on 93, seeing as the map isn't set for it. Also considering that the Z06 already has borderline too much power, how would adding to that be a good thing?

[Sticky]

I've seen this argument before and it seems totally irrelevant to me. The Nismo says on it that it requires 93 octane. The Z06 requires 91 octane. They ran the octane each car needed.... I'm doubtful the Z06 would pick up more than ~10 HP / ~10 lb-ft if it was ran on 93, seeing as the map isn't set for it. Also considering that the Z06 already has borderline too much power, how would adding to that be a good thing?

Actually I think the octane argument is valid. If they are giving it octane booster wouldn't that explain the acceleration results? How do we know the ECU isn't bumping timing? How much octane boost? See the problem?

The Z06 definitely does not have borderline too much power.

[ND75R]

Actually I think the octane argument is valid. If they are giving it octane booster wouldn't that explain the acceleration results? How do we know the ECU isn't bumping timing? How much octane boost? See the problem?

The Z06 definitely does not have borderline too much power.

I simply think in the grand scheme of things it's pretty irrelevant. The Z06 is already faster in every metric where it's not traction limited. Chevrolet could have chosen to sell the Z06 with a 93 octane minimum but the audience for the car is different and it probably would have hurt sales. It was their choice, and so that's how the car is delivered to the comparison. On the stock map I'd wager the difference is insignificant but that's speculation. Then again, it's also speculation that the Z06 would take advantage of the higher octane to any meaningful extent. Hence why I think it's a null point. There's no specific evidence (that I've seen at least) for either side of the argument.

Also, in relation to the power I believe it was Chevrolet engineers themselves who chose to keep the LT4 engine restrained in the Z06 because they thought there was no point in throwing additional power at a RWD chassis. I wish I could find the article that was stated in but sadly it's evading me.

[Sticky]

Then again, it's also speculation that the Z06 would take advantage of the higher octane to any meaningful extent.

It isn't. As we have seen the E85 flex fuel results for example giving a massive bump fuel only.

Also, in relation to the power I believe it was Chevrolet engineers themselves who chose to keep the LT4 engine restrained in the Z06 because they thought there was no point in throwing additional power at a RWD chassis. I wish I could find the article that was stated in but sadly it's evading me.

For a track car they definitely are reaching limits. Some people seem to think it's a roll on race car.

[ND75R]

It isn't. As we have seen the E85 flex fuel results for example giving a massive bump fuel only.

I'm going to reserve judgement until I see the gains that 2 octane really makes on an otherwise stock car. Doubtful that someone will actually take the time to dyno test that though Around here most people run straight 94 octane so we never run into these issues, damn California.

For a track car they definitely are reaching limits. Some people seem to think it's a roll on race car.

Yes, exactly.

[Sticky]

I'm going to reserve judgement until I see the gains that 2 octane really makes on an otherwise stock car.

http://www.chevyboost.com/showthread...n-the-1-4-mile

[ND75R]

http://www.chevyboost.com/showthread...n-the-1-4-mile

With an E85 tune from Jeremy @ Fasterproms, cat delete

But.... Tune and cat delete and E85 gains =/= 93 octane gains....???

[Sticky]

But.... Tune and cat delete and E85 gains =/= 93 octane gains....???

No but how do we know it's just 93 octane?

I thought that post had the E85 only dyno in it. But the car picks up like 40 whp just from the fuel.

[BlackJetE90OC]

I'm going to reserve judgement until I see the gains that 2 octane really makes on an otherwise stock car. Doubtful that someone will actually take the time to dyno test that though Around here most people run straight 94 octane so we never run into these issues, damn California.

And you have proof they added just the right amount of octane booster just for 93 octane.

[BlackJetE90OC]

No but how do we know it's just 93 octane?

Exactly.

Fact is the Nissan engineers that were there to set up the GTR added some amount of octane booster. Then used the 93 octane excuse.

[Sticky]

Isn't magazine testing fun?

[ND75R]

No but how do we know it's just 93 octane?

Fact is the Nissan engineers that were there to set up the GTR added some amount of octane booster.

Is it fact that Nissan engineers added the octane booster themselves? I can't seem to find who added it but Carlos said in response to "what octane booster?[...]", "The stuff the Nissan engineers gave us. I trust them." http://www.reddit.com/comments/2kg9ci
Also lets remember we're dealing with Nissan, not Ferrari here. And the Z06 was still faster so... I'll agree to disagree on the validity of the octane point.

[Sticky]

"The stuff the Nissan engineers gave us. I trust them."

If he didn't say that wouldn't that undermine the whole comparison even further? What else can he say?

[ND75R]

If he didn't say that wouldn't that undermine the whole comparison even further? What else can he say?

Well I think the problem is the ambiguity of the statement, did Nissan give them a car with octane booster already added or did they give Motortrend a can or two and instructions? Either way, I don't feel Nissan is that scumbaggy to cheat. I do totally know what you're saying though.