pcguy2u

Ok, so how many of you beast owners are able to get the lead all the way to the floor on the street, without killing yourselves?

That's the question that came to mind yesterday when we (that's the bosslady that lives here and I - you know, they call them wives) were out on a solo run. I happened on an isolated part of Highway 1 where the road is slightly uphill and straight and one which I have driven previously, so I felt a bit comfortable with putting some lead on the pedal. Couldn't even get to half throttle - I know that pushing down too hard, too fast will cause that beast to break the tires loose and worse, to get sideways on you, real quick.

Mind you, I've driven this ZR1 for over 3000 miles now and have never been able to push the pedal to the floor, except for when the engine is not running. I've done that several times to get a sense for where the throttle is. or could be, at other times. So I kind of know how much pedal is being exercised - and the boss likes to know how much of the power she's experiencing - mostly 1/4 to 1/3 power.

I'm here to tell you that you can't experience a very large part of that beast's huge power. Too many times I tried to push the pedal down all the way and it's just too much for me, at least on the street.

Which brings me to the point - as you know, the ZR1 comes with a two day course at one of the track schools of your choice. I took that course not so long ago and had the opportunity to press that pedal to the metal on a real track, something that I had never done before.

Well, when I compared (mentally that is) the power that my own beast has when I try to push the pedal way down to that of the track ZR1, I find that my own has a huge amount of power by comparison.

This whole question is predicated on why when I was on the course following the instructor who was driving an automatic coupe, that with the pedal to the metal on the straightaway, I was not able to keep pace. After thinking about this a bit more, I realized that none of the 3 or 4 ZR1's that I drove during those 2 days was even remotely comparable to my own stock ZR1.

This thread will probably get picked apart, but I promise to not reveal which track school was involved.

So the real question is, has anyone else who has taken one of the 2 or 3 day sessions had a similar experience?

BEZ06

I went to Spring Mountain and their cars felt just about the same as mine. When I was in a ZR1 doing the lead-follow exercises, I couldn't go WOT behind the instructor's car, but we definitely weren't running all out. Even a 430 hp LS3 C6 is a fantastic performing car.

I did the optional third day at Spring Mountain, which was all track time, with no lead-follow. You were just out on the track to run as hard as you wanted to - and I still never ran over about 80%, but did go WOT in various gears. IIRC, I couldn't take it to redline in 4th on the back straight - I think I topped out at about 140 mph and redline in 4th is around 150 mph with the ZR1 gearing and 6,500 redline, but the pedal was to the floor until the braking zone!!!

I haven't run my ZR1 on the track, but I've had the Z06 on numerous different road courses. It's hard to tell by SOTP sensations that there's a great difference between the two cars - especially when you don't drive them on the same track one right after the other. A data logger will tell you there's definitely a difference, but both cars are so strong that unless you drive them really hard, and one right after the other, your SOTP may not pick up the differences.

When the C6 first came out many former C5 owners said the C6 just didn't seem as fast as their older cars. The C6 was a much better performer, but because it was much smoother it just didn't seem like it was performing better.

My 2006 Z06 seems like a more raw and radical car than the ZR1. When I get in it it seems to say "drive me fast, drive me hard!!!". The ZR1 is more refined and smooth doing the same thing the Z06 does - it does everything better, but it does it so effortlessly that it may not seem like it because it does it so easily, like the difference between the C5 and C6.

As far as going WOT on the street, it's hard to do, whether a ZR1, and Z06, or even a base C6.

In the ZR1 you'll redline 1st at about 65 mph, and 2nd at 93, so it's hard to find anywhere to do that.

Take a look at the great gear/speed calculator forum member leres has posted:

http://xse.com/leres/z06/calculator.html


You can see that he has a bunch of different C6 models you can select from to compare speed in the gears.

So.....yes, I've had my ZR1 pedal to the floor, but not for long!!! You get to redline and high speed so fast that you have to back off. I don't think mine is any different from the ones that I drove at Spring Mountain, so I don't think their cars are detuned at all.

Bob

racerns

I too went to Spring Mountain and did not notice that any of the ZR1s were down on power. It sounds to me that you are basing your opinion on the fact that on the street when you try to get on it you spin the tires but on track that was not happening? There are many things to consider here like the track surface type compared to the road, tire temps, or speed on track as compared to the street. When you are on the road course you are usually going full throttle from a higher speed than you may be attempting on the street. As for you not being able to run down the instructor on the straight that is most likely because he was carrying much more speed through the turns than you and was entering the straight at a much higher speed. These instructors know these tracks so well the difference in power of the cars is not enough to make up for their skill and experience.

pcguy2u

Coming out of the last turn before the straightaway and in 2nd gear, the two cars were very close. With WOT and before shifting from second to third, the ZR1 lost ground. How else can this be explained?

There is one other possibility and I admit to not knowing the reality; the auto coupe may not have been stock??? That may have some impact on the perception, I can't be sure.

But the feel of my Z to the track Z's is definitely not the same..........

Just looking for an answer to the puzzle.

Nick

thebrander

An instructor in an LS3 coupe could absolutely smoke a beginner in a ZR1 if they wanted to.

IndyPacer

I found the ZR1's at spring mountain to be down on power compared to mine also. You have to realize these cars are beat on pretty hard every day! Plus when they run all day long they get really hot, everybody here knows what happens to a supercharged car when the inlet air gets hotter. This is how I rationalized it for myself. I also figured out that the only guy that I couldn't keep up with on the third day had one of the new ones and I was driving one that was almost a year old. I busted my but trying to hang with that one guy but he would leave me everytime on the back straight.

pcguy2u

Good job, never thought of that - and of course, out here on the coast, it never gets hot.

Many thanks

pcguy2u

Help me out here, how does the driver make a difference on the straight when there is no shifting invovled and when both have WOT?

racerns

I pretty much explained that in my post. The instructor was carrying more speed through the corner than you and was able to get on the gas sooner. This gives him a big advantage going down the straight. As they say the most important corner is the one leading to the longest straight. This a good explination on how a less poweful car could pull a more powerful car down the straight.

pcguy2u

But that wasn't the case, I was on his bumper as we came out of the last turn. Granted, he should have started accelerating first but the difference should not have had influence after the turn when we both were on the straight. In fact, I started accelerating before he did, so at first, I closed what littlle gap there was - but after that???

Let me put this in its proper perspective. We are both on the straight (through the turn and accelerating), I'm in second gear and he's still leaving me in the coupe. Doesn't seem real to me..........

I guess we'll leave it at a hot supercharger on hot day with a tired ZR1 driven by a not so experienced driver against a possibly not so stock coupe and a very experienced instructor driver - at least that's what I got out of this thread.

socalspringmountain

Hi all,

This is a very interesting thread.

First off, Spring Mountain does not detune any of it's cars. They come directly from the factory, and that's how we keep them. We want drivers get a true idea of the ability of the vehicles, especially in the ZR1 school.

Most of these items have already been touched on, but I thought I would add my 2 cents.

There are so many variables that go into determining how quickly you can get to full throttle on any car. The ZR1 has so much power, the problem is just amplified. With regards to the street vs the track, tire temp and condition, surface temperature, rubber on the road and driver experience all play a big part.

I have noticed that most people on the track do not get on the throttle as fast as the car will allow. This is a natural tendency because it take experience to get comfortable with the rear tires slipping a little bit, especially when the car is at the exit of corner. The driver is also trying to concentrate on keeping the car on the track, shifting and everything else that goes into driving on a road course. On the street, the car is usually pointing straight and most people are more comfortable with this type of acceleration so it may seem that you can be more aggressive with the throttle. (BTW we don't recommend trying this on public streets )

Regarding the exit of the corner, it's difficult to say what exactly happened there. I wasn't there so I can't say for sure, but from what has been stated, it's quite possible that you got into the corner a little too hot and bled off more speed than the car in front of you. The instructor probably got to WOT much sooner than you thought. I've seen this happen before, it's happened to me. You think you get a run on a lower HP car into the corner by maybe braking a little later than you should and you bleed off too much speed. True, you get close to the car in front, but you are well below your cornering speed, loose momentum and the lower HP car pulls away or you can't catch it. Also, if you apexed the corner a little too early you could have had more steering input than the instructor, again, preventing you from getting to WOT as quickly. Little things can make a big difference.

Things happen very quickly on the track and sometimes perception does not always meet reality. We see this all the time with in-car video in our Radical Race series. An experienced driver will recount an event only to watch the video and see that he did not remember it correctly.

I'm not saying this is what happened, just one possible explanation.

Let me know if you have any questions.

Cheers!

Ken

JDRacing

That's a great analysis, Ken. It's easy to forget that, particularly in a turn like 7 before a long straight, exit speed is so much more important than how hard you go into the corner (entrance speed). Going in too fast almost invariably means using too much of the available traction for turning, and you're still scrubbing speed at a point where you really want to be accelerating with the car pointed the right direction. Particularly if you hit the apex early, resulting in the car being pointed towards the desert instead of down the back straight. Makes a huge difference by the time you reach the other end of the straight to brake for turn 8.

Five trips to Spring Mountain (sixth one coming up next month), too many track/test days to count, several SCCA races, and I'm still struggling to learn and do this consistently.

Beechdoctor

Assuming the OP was at the track during 100+ degree desert heat that hurts the performance a bit too.

High density altitudes and reduced intercooler performance in the extreme heat. My best guess....probably drops power output by close to 10%.

racerns

Thanks Ken for a little more detailed description of what I was trying to explain. Being an instructor myself, I am all to familar with what a student thought they were doing and what they were actually doing.

Even if you saw a 10% reduction in power in a ZR1 you would still have a better power to weight ratio than an LS3 vette that will also be seeing some power reduction from the weather conditions. I think what OP experienced here more has to do with driving experience.

pcguy2u

You guys seem to be skirting the real issue here. Once you leave the corner in 2nd gear, it's all vehicle performance until the driver has to shift and only then is the driver influencing the variables.

Forget the last turn; if the both vehicles are at WOT with the driver's foot on the floor, there should be no comparison between a coupe and a ZR1, unless the coupe is not stock or the ZR1 is not up to par. The gap (whatever it is/was) should begin to close down the straight, and it did not.

This is what I experienced. And, FWIW, my own ZR1 is more powerful than any I drove during the session.

DoctorV8

One factor nobody has mentioned is that the Spring mountain base cars are all Z51 equipped, and therefore have shorter gears than regular LS3's. As you know the ZR1 trans has taller gearing in 1st through 3rd.

The ZR1's second gear is 1.6:1, and the Z51 is 2.07:1. This is HUGE.

So if both cars hit the throttle in second gear at the same road speed, the LS3 car's shorter gearing can easily allow him to get a quick jump, esp when combined with the heat soaked supercharged LS9. Given a long enough straight, the ZR1 would eat the Z51 alive, but given that the LS3's torque at the wheels in 2nd is roughly being multiplied by 30% more than the LS9's....and the straights at Spring Mountain are not 1 mile long.....there's your answer.

{edit} I see you said the instructor car was an automatic, so 2nd gear is even shorter, at 2.36:1. Not sure if the Z51's have different rear gearing, but a base auto runs a 2.73 rear, vs the 3.42 in all 6 speed Vettes. It is entirely possible that his car may have even kicked down to 1st gear (4.0:1) if you were going slow enough....

JDRacing

I disagree. If the lead car is already moving 5 mph faster than the car following by the time they hit the apex and the exit, if the cars are indentical, the lead car will be much faster than 5 mph over the following car by the end of the straight.

The ZR1 is obviously faster than the C6 at WOT, but I think you're underestimating the effect mid-corner and exit speed have on the speed down the following straight. You may have closed up on the car by going into the corner harder, but by the time of the exit, if you're down 5-10 mph you're going to have a difficult time making that up, even with 200 more HP.

socalspringmountain

Let look at this a different way.

Lets assume that the ZR1 was down on power. To be equal to the Coupe, it would mean the ZR1 had lost over 200 HP and almost 200lbft of torque. This would be almost 30% loss of power. This is a significant loss that could not be attributed to a "tired" car and I would think it would be readily appearant in the way the car was running.

I agree that a 10% loss due to environmental conditions is not out of the question, but those same conditions would also have some effect on the other car too. I still think a 30% loss would be due to a major problem.

Do you remember which car you were driving?

DoctorV8

Ken,

The blown LS9 would lose more power due to heat soak than a naturally aspirated LS3, but the whole argument about power is nearly irrelevant, given the fact that both cars run different gear ratios. The torque at the wheels might be nearly equal with the Z51's near 30% mechanical advantage in 2nd gear. See my post #16 above.

Regards,

Sanjay

jvp

I wouldn't be too sure of that, Sanjay. All engines suffer from "heat soak" to a certain extent, and all engines will react the same way. But the question is: how MUCH does it matter?

I think Ken's right on the money: the effect on both engines would be about the same.

jas