Gearing to 167 mph?
Discussion
So what RPM Benno? I reckon we have around 83-84 @ 3,000. That makes exactly 167 @ 6,000 which is a little high. I thought 5,500 is about as high as you want to go with the Rover V8
Which leads me on - if the Griff was higher geared would it pull 180 or so? I realise it's not the most aerodynamic car and you'd need to be a bit mad to try it but it just might be capable of more.
Which leads me on - if the Griff was higher geared would it pull 180 or so? I realise it's not the most aerodynamic car and you'd need to be a bit mad to try it but it just might be capable of more.
At Duxford last year I could only comfortably reach 145mph (indicated) before feeling the need to hit the brakes for the end of the straight. It was roof-off, and rate of acceleration dropped off noticably after around 130 mph. Is this common? I'm looking forward to Bruntingthorpe in May, as I'd like to see just how fast she'll go - I am concerned about high speed handling though, anyone got much experience of this?
Don't have a lot of experience but my 500 pulls quite strongly up till around 150 mph (probably 140 mph in reality). Haven't tried top speed, but once hit 160 mph (on the speedo) with the roof off. Handling is fine but then I have uprated dampers which is supposed to make the difference.
shpub said:
donatien said: So what RPM Benno? I reckon we have around 83-84 @ 3,000. That makes exactly 167 @ 6,000 which is a little high. I thought 5,500 is about as high as you want to go with the Rover V8
Depends on the Rover V8. the 500s have a 6000 red line.
Yes but your bible points out peak power @ 5500. In which case the claimed top speed is past this.
Not the first time a car hits the max by going over the power band of course, I was just curious.
Peak power does not mean or indicate the maximum speed. Providing the engine is producing sufficient power to accelerate the car, it will continue to go faster. If that occurs over the peak power point the car will go faster. With some engines, the power drops off and the car will slow but on others it doesn't.
Steve
Steve
Went to Bruntingthorpe yesterday for one of Don Palmers "Creative Car Control" courses in my Griff 500 and was bloody good fun.
About the top speed question, I'd just about hit 167mph down the straight when Don informed me that the roof might come off so I backed off a bit. It was still accelerating but I must admit that I didn't notice what the rev counter was saying as there were a few birds about on the track and I was a bit worried about one of them ruining the car!!
About the top speed question, I'd just about hit 167mph down the straight when Don informed me that the roof might come off so I backed off a bit. It was still accelerating but I must admit that I didn't notice what the rev counter was saying as there were a few birds about on the track and I was a bit worried about one of them ruining the car!!
Yeah the car was quite stable at those speeds even though it was quite windy on Monday. I was aiming to get over 170 and I think that it would have got to it , or rather what was marked on the speedo anyway!
Pulled strongly up to about 150ish but was still gaining speed when I backed off. The straight there at Bruntingthorpe is bloody long so I'd be interested to here what anybody else could get. The other guy on the course took his M3 to an indicated 160 with 3 of us in it and I thought they were supposed to be restricted!!!
Pulled strongly up to about 150ish but was still gaining speed when I backed off. The straight there at Bruntingthorpe is bloody long so I'd be interested to here what anybody else could get. The other guy on the course took his M3 to an indicated 160 with 3 of us in it and I thought they were supposed to be restricted!!!
shpub said:
donatien said: So what RPM Benno? I reckon we have around 83-84 @ 3,000. That makes exactly 167 @ 6,000 which is a little high. I thought 5,500 is about as high as you want to go with the Rover V8
Depends on the Rover V8. the 500s have a 6000 red line.
Interesting .... My limiter is set to 6500 on my 4litre .... I cannot get past 150 - 155. without bouncing off the rev limiter. I suspect my problem is gearing. ( see post on wedge forum)
Well my whole point was that if you "nominate" a top speed then is would make sense for that to co-incide with peak power whilst in top. The Griff seems a bit short-geared to me, which of course in some way accounts for its' blistering acceleration. No complaints there of course 
I've never had it that far but it seems that 167 would be about 6,000 rpm. 500 rpm over peak power. As Steve Heath has said the car will accelerate if the engine is still delivering enough power to do so.
The question then really is maybe, how high could you raise the gearing? Would a Griff touch 180 with a different final drive?
For comparison how are the Cerberas & Tuscans geared. Assuming you could pull peak power in 5th what would that equate to in road speed?
Dave
I've never had it that far but it seems that 167 would be about 6,000 rpm. 500 rpm over peak power. As Steve Heath has said the car will accelerate if the engine is still delivering enough power to do so.
The question then really is maybe, how high could you raise the gearing? Would a Griff touch 180 with a different final drive?
For comparison how are the Cerberas & Tuscans geared. Assuming you could pull peak power in 5th what would that equate to in road speed?
Dave
But obviously I needed a long 'test track' 
It also felt pretty stable at the time.
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