26 replies to this topic

[Danny Steyn]

Just thought I would create a thread to provide a discussion venue for the VVT/99 parity debate before I fly to Australia. 

 

(There are moves afoot to help the NA cars, but for this discussion lets keep it to the 99/VVT NB cars)

 

With regard to the 99/VVT parity discussion, since there is so much talk going on, here is what I saw at NOLA. All drivers canvassed with one exception were pretty happy with the status quo. There were no outlier cars, everyone was really close in the power department. It all came down to setup and rhythm.

 

There was a good mix of 99's and VVT's, with the VVT’s now running the extra weight at 2425/2440 and while the VVT's prevailed on this track, I think it will be a different story at Road Atlanta.

 

We dyno’d both my cars prior to NOLA, and they are the two best engines I have ever had. Based on the dyno traces anyone looking at the graph would choose the 99 over the VVT as we spend more than 85% of our time above 5800 RPM at NOLA. However there are several places where we are in a state of sliding, and I suspect that the torque helps in those situations. The VVT appears to be easier to drive, and the chassis feels more “Cadillacy” while the 99 definitely feels more racy and more responsive.

 

At NOLA I turned two pretty fast laps, both in the 1:58.0 second range. I ran a 1:58.070 in the SM qualifying session in my VVT, and I ran a 1:58.032 in the STL race in my 99. The Velocity/Time traces are almost identical.

 

Here are my dyno traces pre NOLA and my best laps in each car.

 

 

 

 

 

[RazerX]

If the blue is the 99 in your velocity chart, it is interesting that you carried more noticeably speed in T15/16 in the 99.  

 

Are you sliding in T11 - T12?  hence the VVT toque and the slightly more velocity at 9500 feet?

[Ron Alan]

Danny...what is your goal here? Or I should say do you have an opinion?

Are you happy with the change? Or unhappy?

And thanks for sharing! These numbers for me seem really close to what I have seen here which is reassuring!

[Danny Steyn]

Ron - just starting a discussion. There were several naysayers that felt the move to add the 25lbs to the VVT was premature, yet the VVT's prevailed with the weight. There are a few that still feel the VVT is still an overdog. Hoping that sharing some of the data that we are seeing will provoke a healthy discussion. From my perspective the cars look VERY equal, and as always there will one version will do better at certain tracks

[Danny Steyn]

Speed, this is the first time for me at this track. I most certainly do NOT have it down. For the most part the variations in the velocity traces are from not hitting my marks perfectly each time. For this discussion I am more interested in the acceleration traces of both cars which appear to be almost identical from the corner exit all the way to the braking point.

[B(Kuch)Kucera45]

Danny,I first want to say thanks for sharing all this info even though I don't have either of the models you comparing. This info proves a great point that I would like to point

You can clearly see the diff.in the dyno numbers between the two models yet you almost run the exact lap times.

Now I'm asking because I'm not 100% sure and am no way trying to bring the NA into this parity between the models you are talking about.

Isn't the on track data way more valuable then the dyno numbers when it comes down to a parity issue or adjustments ?

If they use track data as part of deciding parity between the models do they use in traffic data as well as open track data ?

So how much diff.does the two models feel in traffic behind another car ?

Does one outshine the other in traffic ?

[pat slattery]

Based on dyno graph the 99 looks to be the clear winner but the weight penalty is not factored in

[jdmrrs]

The area under the torque curves, 4500-6500, is identical.

[Jim Drago]

Based on dyno graph the 99 looks to be the clear winner but the weight penalty is not factored in

I think that is the point of the thread.. we dont race dynos... 

The vvt car races better than what the dyno sheets show.  I chose my 00 as "I" feel my 00 is better than my VVT, with or without the weight. 25 lbs is all but a non factor here IMO. The "penalty" is more mental than reality IMO. Ironically, my VVT dynos REALLY well, but it doesn't show up on track. I will be racing my VVT at atlanta, so maybe I will pull down the average

 

Jim

[Danny Steyn]

I think that is the point of the thread.. we dont race dynos... 

The vvt car races better than what the dyno sheets show.  I chose my 99 as "i" feel my 99 is better than my VVT, with or without the weight. 25 lbs is all but a non factor here IMO. The "penalty" is more mental than reality imo. 

I will be racing my VVT at atlanta, so maybe I will pull down the average

 

Jim

 

Jim that is exactly the point I was making. On paper the 99 is the TOTALLY dominant car, even without the weight penalty that the VVT has, yet on the track it is way closer than what the dyno indicates. 

[robertcope]

Would love to see your speed/distance with RPM data next to it. I don't see how the VVT car is keeping up unless you spend a lot of time in the 4000-5500 range.

 

robert

[Pat Ross]

Robert,

 

Many more factors than just HP & Torque factor into the equation.  What is the rolling resistance of each chassis?  Is the "form drag" slightly different?  All the dyno tells you is the net of engine output minus frictional losses in the drive train.  It doesn't consider the front wheels, front wheel brake drag, etc.

 

Pat 

[38bfast]

also note the the VVT chassis is different than the 99. I could consider it stiffer in several areas. Not saying it is the golden bullet but there is a difference. 

 

Also if it is a slow start the VVT has its advantages. 

[Dave D.]

I would think the minimal extra chassis bracing of the VVT is a non issue in a race car once you install a roll cage. 

[Steve Scheifler]

The difference in the power curves are visually exaggerated by the scaling (starting at ~74 hp/tq). The average difference in power through the usable RPM range is certainly more than I'd want to give up, but not enough to be conspicuously dominant and easily overshadowed but a number of other factors.

Chassis stiffness - Since we can't tie into the cross-members, factory stiffening likely carries over to some degree despite our cages.

[Todd Lamb]

The VVT has a much different feel to it from many perspectives. Even in the paddock, dipping into the throttle gives much more throttle response than the 99.

On track, applying 99-style throttle percentage in the VVT results in more weight transfer off the front and a bit more push than a 99. So using the throttle as an on/off switch is even less desirable than it is in a 99.

Handling wise, the VVT feels like it has a tad more stability. Not necessarily more grip, just absorbs the bumps a tiny bit better allowing for better power down. Add that and the additional torque, and the VVT gets it done off the corners.

Having said all this, my comparison was back in the days of compression-gate and no 25# weight penalty, so the VVT has lost a bit of its edge. Probably is pretty darn close right about now. Still, wouldn't take a VVT to Daytona. We're building a 99 for in-house use.

[FTodaro]

All of the factory external bracing i have removed from my VVT car, clearance issues. I am not even sure its legal to run it. Someone smarter than I can comment, but i think the 99 and the VVT share all the same suspension components, except the front upper control arms and spindles. 

Unfortunately, adding the wt to the VVT to even out its TQ coming out of the corners, compounds its short comings at the top end, so i would also expect the 99 to be the dominate car between the two at Daytona.

[Dave D.]

I'm pretty sure the spindles and upper control arms are the same between '99 and VVT. 

[Marc Cefalo]

Greetings from ROME!

 

the taxi driver's here would put most of us to shame on track.....lol

 

the under car bracing is significantly more involved in a VVT car and a total PITA when swapping gearboxes at the track.

 

other notable chassis differences between VVT (01-05) and 99's (99-00):

 

vvt upper arms are different with more bracing and different balljoint.

 

vvt upper balljoint castle nut is thus different.

 

vvt lower front control arms are different.  there is an inner layer of steel bracing which can be seen when looking through the one inch hole in the arm.  this piece MAY have been superseded by Mazda to replace older 99-00 front lower control arms but i'm not 100% sure. 

 

interior unibody bracing by the trans tunnel to firewall area in the interior is much larger.  most never realize it unless you look at both examples side by side.  one of the reasons you can fit a 01-05 console in a 99-00 chassis but not vice versa unless you modify the underside of it.

 

all in all, once a proper cage is installed, the chassis flex between the two is nil in my opinion.  after owning and driving all 4 drivetrain generations, the different "feel" from a vvt car to a 99-00 car is hardly noticeable to most unlike the jump from a 1.6 to VVT.

 

now since the results from NOLA and the respective lap times are in, can we please stop worrying about one car being an overdog compared to another.  there are more important things to do like continue racing in the south and getting ready for the season in the north!

[LarryKing]

How could I possibly value the opinion of someone who squanders their time in Rome (ROME!!!) to read this crap?