Rolling Road session

Technical Area for all the problems you have in the garage
Colin Newbold
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Re: Rolling Road session

Post by Colin Newbold »

Paul Blore wrote:Is that in the MG or the Fiesta Colin?

Fiesta Paul. I managed 2 pirouettes coming into the chicane on a test day there last Thursday but didn't hit anything... nevertheless, will try and avoid same on Sunday :lol:

Sorry Roger, seem to have hijacked your post...
"How you see yourself is all very well, but it's how others see you that will determine the results you get as a leader!"
CobStang
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Re: Rolling Road session

Post by CobStang »

Roger
Yes of course to your comments, I was just surprised at your total advance figure.
Lets hope you can drive it and enjoy it now.

M
Early B.R.A. Warmed 3.9 Rover, 5 sp, 3.07 rear, Fully adjustable front suspension with AVO coilovers, 4 link rear suspension AVO coilovers and Panhard bar, Big 2 pot front calipers, rear discs, servo'd, adjustable front / rear bias, scruffy paint job !
Paul Blore
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Re: Rolling Road session

Post by Paul Blore »

Do you need to use Super Unleaded with only 10:1 compression ratio Roger?
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Roger King
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Re: Rolling Road session

Post by Roger King »

Paul Blore wrote:Do you need to use Super Unleaded with only 10:1 compression ratio Roger?
Certainly. Anything less and it pinks like mad - same for any Ford or Mopar V8 I have built, from 260 to 440. Never less than 9:1 or more than 10:1. Even the Mini's A-series, at 9.5:1 will pink furiously on standard unleaded. For Norway, Sicily and some areas of Spain I have to carry octane booster.

CR isn't the be-all and end-all of performance - the Lotus 907 engine, for example (Esprit etc.), in non-turbo form was always under 10:1. It always impressed me that Colin Chapman could get more power out of a 8.4:1 1973cc engine than Triumph could out of a 9.5:1 2500 with fuel injection. Goes to show it's down to the design characteristics, especially with modern fuels.
Paul Blore
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Re: Rolling Road session

Post by Paul Blore »

I'm surprised that your Cobra pinks with such modest ignition advance.

My FE runs 10:1 compression ratio and I've never used Super Unleaded in it and I've never heard it pinking. When I took the heads off last year, there were no signs of detonation on the Pistons either.

Are you sure it isn't just your tinnitus that you can hear? :lol:

Paul
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