Gearing to 167 mph?

[andysgriff]

Took mine to somewhere in the 150ish range a while ago whilst blasting past a Porsche Boxter.

It felt as if it could go on as it was pulling strongly but any faster and I would have needed air traffic control clearance.

[Alex]

I had my Griff 500 (now Steve Heath's!) upto an indicated 165mph on a French Autoroute (er, they'd closed it specially for me...) That speed does indeed arrive beyond peak power at around 6200rpm in 5th. The true speed is probably a few mph lower though.

[davidn]

I'm not sure how much this is going to be frowned upon but here goes. I have a practical example of a 500's top speed. Approx 5 years ago I owned an Esprit Turbo (yes I've seen the light and bought a Griff) followed a mate in his 500 both maxed out, the Lotus hovered around 158mph (other half was watching the speedo)and the Griff ever so gently edged away.
Yes both totally ashamed at our own behaviour but an exmaple nonetheless, so I guess the Griff should be somewhere around 160+.
Not nicked yet, David

[julianhj]

Well, PC or not David, you have my admiration for pushing that little bit harder than I've ever dared. I bottled out at 145-ish when I saw a car a little over a mile ahead of me.

Usual disclaimers apply.
Apologies to those who think I'm a tw@t for attempting such speeds...

[Leadfoot]

Leadfoot said: My Griff will definately pull 600rpm in 5th But obviously I needed a long 'test track' It also felt pretty stable at the time.

I should have said at the time: The speedo was showing about 185 at the time, ,and yes it was 6000 rpm. Lol

[EdT]

At Bruntingthorpe yesterday mine didnt want to do more than 6K rpm in 5th.. but maybe having the roof off slows it a little.

Takes quite an effort with the brakes to stop from that speed I discovered .. especially if you miss the braking sign. Oops.

Ed

[david beer]

I forgot to see the revs but my speedo showed just over 165 on the first run, slightly less on the second. I was roof on as the difference is well worth it!!

[EdT]

Thinking further on this .. it's a shame the 500 doesnt having a longer 5th (or a 6th!) gear..
Last weekend at Bruntingthorpe the car hit 6K prm in 5th, and there was still a good half mile of the runway left

Ed

[anonymous-user]

1. Bigger wheels
2. Swap 5th ratio
3. Install a T56 box

[shpub]

Still no guarentee it will go faster. Gearing it for 300 mph doesn't mean that it will get there.

[craigw]

want to have a try on 27th April Chaps.......

www.pistonheads.com/gassing/topic.asp?t=34168&f=65&h=0

[EdT]

shpub said: Still no guarentee it will go faster. Gearing it for 300 mph doesn't mean that it will get there.

Fair enough Steve, but I felt that with a different final ratio a good few extra mph could be found

Ed

[EdT]

dod said:
2. Swap 5th ratio

Right then, I'll do that.

Right then, how do I do it?

Ed




>> Edited by EdT on Thursday 3rd April 22:11

[shpub]

Remove gearbox. sell wife /kid into white slavery. Hand cash to someone who can rebuild gearbox. Get box back. Re install.

Budget about £3-4000. Also you need to specify what ratio you need. Trial and error is not to be recommended.

[RichB]

Or change the ratio in the differential?
This retains the ratio difference between gears but simply shifts everything up a bit, which given the pulling-power available in first gear shouldn't be a problem. Rich...

[anonymous-user]

It turns out that the T5 was also made with a 0.63 fifth.

See here

This would give relaxed highway driving, and with enough power/torque/road/guts, could easily see you close to the magic 200 mark.

You should be able to buy a fully reconditioned box for around £1000.

[RichB]

Interesting! So which ratio 5th does the Griffith have? R...

[anonymous-user]

0.8

[trefor]

www.gearboxman.com

[EdT]

this is all getting very interesting, as Rich just said. If my 'box ever goes bang I will really look into this (or if I ever have a spare grand knocking about)

Ed