endurance record

[ZRXMAX]

Originally Posted by WVZR-1

What makes you think/believe that it was a "production" ZR-1?

Pot stirring David ?
Yes, the overall car was prepared for the record run. The engine was pulled from the assembly line for a cosmetic reason as the story goes. Given that the throttle was restricted to 70 to 75% from wide open and the Z was running much of the time in the low 180s it seems they might have super tuned it



I'd say it was a very "purpose built/assembled" car - production is a "stretch"!

Exhaust work for sure. Beyond the oil coolers, fuel cell and other mods required for the run I would be quessing.

[XfireZ51]

The rear gears were taller in order to keep the motor below the 6k rpm level.
According to accounts I heard at Gathering, they wanted to avoid water pump cavitating. So 5500rpm was a target for the 175. Obviously, there were safety mods that necessarily were part of the overall prep.

[ZR-1 Franz]

In my opinion The ZR-1 record car was still a production car, even with
all that tuning, because you can do these modifications to your ZR-1
without any problems. It is a car like yours, a car you can buy.
A car like the VW Nardo is a prototype, a purpose built car for what ever!
It's not so easy to get one and have it parked in your garage !!

Best greetings from Switzerland,

Franz

[Fully Vetted]

Originally Posted by XfireZ51

The rear gears were taller in order to keep the motor below the 6k rpm level.
According to accounts I heard at Gathering, they wanted to avoid water pump cavitating. So 5500rpm was a target for the 175. Obviously, there were safety mods that necessarily were part of the overall prep.

Yeah, it was explained pretty well at The Gathering. They actually took an engine right off the line. In fact, they happened to pick an engine that had been rejected in QC for some reason and repaired. Thanks to the gearing the car was never ran at full throttle. They placed a block of wood under the accelerator pedal so the drivers could just keep it planted. They also had to carry certain parts in the car for repairs. In order for the run to count as a record if it broke down they could only use parts that were in the vehicle and the driver had to do the repair. If I remember correctly there was only one issue and it was after 24 hour record was set and they were going for the 5000 mile record (or visa versa) and I believe it was a coolant line maybe.

The only mod I kind of have an issue with is the gearing swap. Lowering the RPM will definitely have an impact on the endurance aspect which was what the record was all about to begin with.

[Hog]

Too bad they didnt just run the record in 6th gear.

5th gear with 3.08 gears at 5500rpm and a 25.7" tire gives you 182 mph.
3.33:1 gives you 167mph
3.45 is 162mph
3.55 is 158mph
3.70=151mph
4.11=136mph

In 6th gear with 4.56 gearing you can still run 184mph
4.11=204mph
3.70=227mph
3.55=236mph
3.45=243mph
3.36=250mph
3.08=273mph
But the driveshaft would be spinning at twice th engine rpm, or 11,000rpm in 6th gear with 4.56 gears and 5500rpm engine rpm at 184mph.

peace
Hog

[XfireZ51]

What was their actual average speed given that 175 includes stops and accel/ decel times?

[WVZR-1]

Originally Posted by Hog

Too bad they didnt just run the record in 6th gear.


peace
Hog

A 6th gear run would likely have fallen short of the 24 hour record by 23 or more hours.

[Hog]

Originally Posted by WVZR-1

A 6th gear run would likely have fallen short of the 24 hour record by 23 or more hours.

Why?

peace
Hog

[WVZR-1]

Originally Posted by Hog

Why?

peace
Hog

Heat and stress would have killed the ZF! Are some of the "catastrophic" failures of the ZF induced by abusing 6th gear? Maybe. Ask the builders and I believe they'll all mention disregarding 6th gear for all "sustained" high speed driving.

[Hog]

Originally Posted by XfireZ51

What was their actual average speed given that 175 includes stops and accel/ decel times?

Since teh 175 includes some periods of time at 0mph and at speeds other than 180mph, 175mpgh IS the cars actual average speed over the 24hour period.

To get the figure you seek, the stopwatchs would have to have been stopped everytime the driver deceled for a pit stop, the restarted when after the stop after peak speed had been re-attained. I doubt this was calculated.

peace
Hog