AirBusPilot

Is the LPE car 650 rwhp, or is it rated per the same SAE spec the LS9 is?

feeder82

b.s.

Kaploww

Lingenfelter ran 2.73 rear end from the automatic for the top speed run, and made the run in 5th gear.

650hp SAE, not at the wheels.

Any other questions?

I have car #4 live in Germany, and the A7 (autobahn) is about 3 miles from my house.

Life is good.

RED99

UniqueDoug

TexSon

That's the point, this started as an email from the forum that the C5 is faster than the C7, not as a highly modified C5 is.

I see since it started it is now " 650hp lingenfelter vs Zr1 top speed", not "Stock C5 vs Stock C7." As my last line says a highly modified car will beat a stock one, no question.

camisade

When you're talking "fast," people who live in magazine articles fixate on the top end speeds achievable in only a few venues in the country, under very rare or pure test conditions (in other words, artificial and irrelevant metrics). People who DRIVE cars focus on lap times (or perhaps 0-60 or 1/8 mile "dash" capability, for those who've never been to the track or grew up in cars that couldn't really do anything other than a straight line sprint). ;-)

Bruze

From the email article:

"In a rough sense, that’s the difference a cd of 0.07 can have on top speed. Of course, gearing is also an important factor in top speed. No information is given about the gear ratios of the Lingenfelter car, but my money says it wasn’t running a stock setup — a standard C5 is rated for 285 mph in sixth gear; a 2009 ZR1 is rated for 224 mph in sixth. It’s likely Lingenfelter’s car was running ratios similar to the ZR1 in order to blow 25 mph past 200."

What am I missing here? Unless physics has changed since I was young, you can't simply gear a car up and have a higher top end. All else being equal, it takes more horsepower to go faster.

A calculated "top" speed in overdrive is meaningless; if any car is overgeared it will not reach maximum RPM (because it doesn't have enough horsepower) and will have a lower top end than it will in 5th (or whatever the next lower gear is) a gear that is -- hopefully -- designed to run at maximum RPM to get the maximum speed possible with the HP, weight, and drag taken into account.

Or something like that.

xarkey

Sometime in the 60's Pininfarina who designed the great bulk of all the Ferrari models we know and love, did studies in wind tunnels which created the coefficients quoted in the article. He published a small book documenting many of his results and one of the cars he designed had the lowest coefficient ever built into a car. The results are found on nearly every SUV, Sedan and can be seen on every car which has what we know as the coke bottle shape. On those cars the waist shrinks and then flares out to close out the rear of the cars. He was a genius and left us with a great body of work.

SweetSavannah

I had one of LPE's twin turbos a few years back on my 2002 Z06 with an LPE 427 c.i. motor. It had a 3-stage boost controller which allowed me to set the boost at 5, 8 & 14 lb. At 14 lb., the car dyno'ed at 710 RWHP and 790 RWTQ. It was completely docile on the street, and a raging beast on the track. By track, I mean road courses. I'm a nationally certified instructor for BMW and a host of other car clubs, and this car was a handful to keep it pointed straight exiting corners. On a couple of occasions, it nearly bit me. On one that remains seared in my mind, occurred at Lime Rock Park when exiting the infamous 'downhill'. After warming the 'R' - compound Hoosiers, I rolled into the throttle at 105MPH in 4th gear, and the car lit up the rears and twisted me sideways. Fortunately, I caught the slide and managed to complete the session without further incident.

LPE did a great job with this version, but running an LPE TT motor on a road course is a whole new challenge in both judicious management of the throttle as well as effective heat extraction.

SaintsFan

So we can compare CD's to each other and agree that the C5 is slipperier than the C6 or C7. However the original article seems to claim that the .7 difference in CD is primarily the reason for the difference in top speed. I am not an aerodynamic engineer, and thus I can't say as to whether or not the difference in CD is the biggest factor in top speed. I would first want to know what the difference in gear ratio is. As with any comparison, we need to make sure those factors that are considered equal, are indeed equal. It is not sufficient to just elude to a difference in gear ratios has having effect but then conclude the difference is the CD.

jackthelad

Chevy quoted a CD of .29 for the coupe when the C5's starting getting road tested back in 1997. The more doodads and downforce you add, the higher the CD and the lower the theoretical top speed becomes for any given power output

Another example, recent Z06 C7 road tests have quoted Chevrolet as saying that the Z07 package - splitter, rear spoiler, etc., knocks 9 mph off the top speed.

You want to scorch the Nurburgring? Add downforce. You want to go as fast as possible in a straight line? Remove downforce.

TXWMH

Well then I'm glad I bought a C5.

CorvetteBrent

I've never made it to 200, but I've gone 165 MPH at night in my supercharged Corvette C5 (with the pop-up headlights on). The car's speed was still increasing, but I ran out of room and had to let off of the gas.