Roaring Forties GT40 tops 280 km/h !

OK guys. The challenge is on.

Yesterday, Brendon Manion’s RF40 (the car that was entered in this year’s Targa Tasmania) was officially clocked at 282 km/h!!! (176.25mph). No, this isn’t a tall tale about the day we buzzed a quiet little country town with the local constabulary on tow. This run was done at Avalon Airfield in country Victoria, as part of an article for Motor Magazine. The article lined up some of the fastest cars in Australia and used a speed trap to get the actual speed (as opposed to the speed on the clock, which apparently had the needle butted up against the end-stop beyond 300km/h). Tacho, I’m told, sat on a cool 6,800 RPM. Hmmm maybe with a slightly taller final drive ratio… who knows??? The pilot was a well-known local race-car driver come media personality, by the name of Cameron McConville. It was interesting to hear that he made some pretty positive comments about the stability of the RF40, both at speed and under hard braking.

The car itself was basically standard with one of Gordon Levy’s Stage 3 engines putting its power through a 3U 016 Audi transaxle (who said that these gear boxes can’t handle 350+ horsepower /ubbthreads/images/graemlins/smile.gif ). The single nostril was used and a set of secondary restraint pins helped hold down the rear clip (just to be sure). The article should be out in the August or September issue. Can’t wait to read it.
 
Chris L.

That's awesome. I was told that the originals with the ZF had 3 overdrives. That, with the added horses, allowed for the 200+ MPH (and I'm sure there were other changes too). Any chance of Brendon's getting there with the 016?

Have fun!

John /ubbthreads/images/graemlins/cool.gif
 
[ QUOTE ]
HP is not as much a concern as torque is /ubbthreads/images/graemlins/shocked.gif

Ian

[/ QUOTE ]

Not at 6800RPM it isn't. I was under the distinct impression that it was HP that gets you through wind resistance at really high speeds. My car is geared for about 185MPH at 6800RPM - at which it develops 430HP, but not as much as at 6600RPM which 449HP. Max torque is 418 ft/lb at 4800RPM.

176MPH is BLOODY quick though!! /ubbthreads/images/graemlins/cool.gif
Regards,

J.P
 

Ron Earp

Admin
According to my data on the 3Us and the one's I've brought in they have a 3.89 final but a 0.64 fifth gear. At 6800 RPM and with a 26" tire it'd be 208.62 mph on top. Sure it is a 3U?

The 5N box, the common one, is a 4.11 final with a 0.73 fifth. At 6800 RPM and a 26" tire it would be at 175.54 mph on top. Real close to what is posted.

Ron
 
Maybe there was some confusion going on above. I think the torque comment was in reference to the strength of the box (torque is the driving design factor of transaxle). I think the HP response is in relation to vehicle top speed. The main factor here is to have the car geared such that the engine is at its HP peak (not torque peak) at the top speed. You will thus achieve the highest top speed possible at the HP peak (where drag force balances force produced by wheels).
 
I heard it was still accelerating but ran out of runway. Maybe Gordon could tell us what rev limit his engine can run to. Regards
 
The engine in that car is not a normal stage 3 engine. I custom built a long rod, streetable but full race, 11-1 compression 306 for that car. It will rev to 8000 and build power all the way there. I suggested that the rev limit be set at 7500, but the boys at RF set it at a conservative 6800.
Ron you are correct about the gear ratio's, it is a .64 5th. The tire size was 25.2 diameter. The car has a stock clutch in it and I do feel that it was slipping a bit. I have encountered that is several high speed cars because of the wind drag. For guys that drive their cars on the street the racing style clutch needed to really hold the power at that kind of speed would be very uncomfortable and hard to drive on the street.
I feel with a little tuning, a race clutch, and a few minor tweekes, the car could see well over 300K.
 

Ron Earp

Admin
Chris,

It isn't too clear from the post - did the engine have the rev limit set at 6800 RPM, was that a self-imposed limit, or would the car not pull any more RPM?

Ron
 

David

Lifetime Supporter
Ron, From Gordon\'s Post

[ QUOTE ]
I suggested that the rev limit be set at 7500, but the boys at RF set it at a conservative 6800.

[/ QUOTE ]

Dave Lowell
 

Ron Earp

Admin
Re: Ron, From Gordon\'s Post

I caught that too, but I was just double checking to find out exactly what the case was. One post indicated it was still accelerating so that kind of muddies the waters.

Ron
 
[ QUOTE ]
It isn't too clear from the post - did the engine have the rev limit set at 6800 RPM, was that a self-imposed limit, or would the car not pull any more RPM?

[/ QUOTE ]

Ron,
In general conversation, I was told that the engine had a "soft" limit set at 6800 RPM, and a "hard" limit at 7000 RPM. We didn't really go into the technical aspects of it so I'm not sure how the soft limit was achieved. Maybe Robert Logan or Gordon Levy might be able to chip in here.
 
Chris, In the MoTeC system, The rev limit has 2 settings. 1 is a soft setting that will let you know when you are getting close to the wanted limits. It stops building power. The second is the hard limit that under accelleration, cuts the ignition out to make sure you don't go over what is set. The rev limit is good insurance to help under hard driving. Rev limiters don't work in missed shifts or down shifts.
 
To the Australian members of the forum. Thought you might like to know that this article is now on the stands in the November issue of Motor Magazine.

Interestingly, the only other road cars to out-do the RF40 in this test were a Lambo Murielago, and a wildly modified Nissan Skyline GTR V-Spec R33 (phew that was a mouthful). The Holdens didn't cut the mustard, and only managed a decent run after the build problems were eventually ironed out. (Sorry Holden fans. I couldn't resist the dig /ubbthreads/images/graemlins/laugh.gif )

Cars in the test in order of speed...
HSV GTS Sedan
Masserati Coup Cambiocorsa
Holden Monaro CV8 Targa (Brocky's Targa race car)
CSV Mondo GT
Roaring Forties RF40
Jaguar XJS 6.0 (Race car)
VT Commodore V8 Supercar (You know, the one with all the Ford bits - Oops another dig /ubbthreads/images/graemlins/laugh.gif )
Lamborghini Murielago
Nissan Skyline GTR V-Spec R33
 

Ron Earp

Admin
What was the testing critera? Top speed? Lap time? Quarter mile? Can you post some results so we can see what the cars did?

R
 
In the words of the article, the test was a "no-brainer" /ubbthreads/images/graemlins/laugh.gif . They just put the pedal to the metal until they either ran out of puff or air-field. The car with the highest top speed wins. They said almost nothing about the selection criteria, other than their desire to have some Fords and Holdens and a Ferrari that failed to show up.

Speeds in km/h (100km/h ~ 62 mph

HSV GTS Sedan - 260
Masserati Coup Cambiocorsa - 264.9
Holden Monaro CV8 Targa - 271.4
CSV Mondo GT - 280.5
Roaring Forties RF40 - 282.1
Jaguar XJS 6.0 - 283.1
VT Commodore V8 Supercar - 295.1
Lamborghini Murielago - 303.8
Nissan Skyline GTR V-Spec R33 - 306.9
 
It seems like only yesterday there were lots of questions about down force and the aero capabilities of the GT40 body. At 170mph+ I would think aero was a factor. Did the car feel light or were there add ons to the body to combat lift? I am pretty sure some of us would love to hear what was done to make this car not fly.
 
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