Birkett 6hr

Racing and trackday chat
erictharg
Posts: 680
Joined: Thu Jan 29, 2009 7:50 pm

Re: Birkett 6hr

Post by erictharg »

Race Report:
Weather forecast said cold and clear. It was cold for sure! Didn't stay clear either.
Scrutineering was fine - had a nice older guy who races an original Eleven check mine over. Tested the cut off switch (which does not often happen with the engine actually running) and seem to have lost the ignition warning light. Battery charge held up OK through the day so may be the bulb as opposed to the alternator. The cut off switches can fail over time so onceI've diagnosed the problem I'll replace if necessary. He also advised me to ditch the solid state fuel pump and go for the bigger Bendix type. He's seen a lot of the solid state pumps go AWOL without warning.
Practice was pretty uneventful. Too busy to really get in a good lap. More a case of just remembering where the circuit goes.
We has three Lotus replica's in the team. Mine, plus Ken's Mamba 23 replica, and Paul Richardson's Tiger 23 replica whihc he'd managed to fix after his off at Mallory. The others were Cheng's Cobra, John Plant's Allard replica and Graham Paddick running a Kougar. Not his though - he's done a ring on his so John Plant had lent Graham his Kougar. Nice diverse bunch of cars. Meant we were in Class D though which is Sports Racing cars over 1700cc. Mine could have run in Class A - road going under 1700cc!
I was first man so took the start. Fortunatley an incident free start (not easy with 62 cars on the grid) but I let the engine bog down agin so slow off the mark. Not that its important in a 6 hour race. If the revs drop below 4000 at all I've had it setting off.
Good first stint (30 mins approx) having some fun with an original Lotus 7 and a Rover 220! Hitting 6700 in top at the end of Hangar Straight. That's about 118mph. Must remember to brake earlier for Stowe!
Back to the pits. Re-fuel (Not much over half a tank used in 30 mins), snug up the rear barkes a notch and that's it. Hang around, drink coffee, watch people fixing ther cars...
Second session was another 30 mins, and also incident free. Good dice with an MR2 at one point. But have to remeber this is not a sprint race. It's all about consistency and reliability. Ease my shift point back to 6500 and take it easy.
Late afternoon we had a sudden shower of hail that caused chaos on the circuit, with lap times dropping by almost a minute. John Plant was out at the time. He admitted it was a bit worrying going down Hangar straight getting sudden wheelspin in top! His Allard does have maybe 600hp, so...
We are all running well with no problems until Cheng's Cobra failed to come around halfway through his second stint. Graham had to go out early so I spent the last 40 mins in the garage belted up and ready to go. Not needed as Graham finished the race off for us with no problems. Cheng's problem was another rear drive failure. This time the hub flange. Seems that 700hp and 1200kgs of car will take its toll one way or another.
So another good performance from the Eleven. I was running times close to both Ken and Paul in their 23's. Best lap 2:42. Pleased with that. The car continues to impress with it's durability and relatively good performance considering how standard it is.
List being made for winter refresh but nothing radical. Engine and box out and check over. New shells and big end bolts for the engine providing nothing else comes to light. Strip and new bearings for the g/box. Fresh clutch.
Otherwise preventative stuff. New fuel pump, water pump, alternator. Better silencer for sure! May try some different tyres as the 185/70 A012's mean I'm running higher ride height than ideal - if I drop it much more they will rub. The car could run a good 30 to 40mm lower. Either the 185/60 A539's or the Avon ACB9's seem good alternatives.
sgrant
Posts: 333
Joined: Thu Jan 29, 2009 10:44 am

Re: Birkett 6hr

Post by sgrant »

Nice one Charles and ta for the update...
adamwilkinson
Posts: 187
Joined: Wed Jun 29, 2011 12:17 pm

Re: Birkett 6hr

Post by adamwilkinson »

Going from the A021's to A539's seems strange - a step backwards in performance levels. The A539 is an ok tyre, i had to run them on the Locost but wouldnt choose to run them on the 11.
erictharg
Posts: 680
Joined: Thu Jan 29, 2009 7:50 pm

Re: Birkett 6hr

Post by erictharg »

I know what you mean. The A021's seem to work well. They are supposed to be intermediates and so are quite soft, but the light weight of the Eleven means they can handle the dry with no problem. Plus when it is wet they work pretty well too. I've just seen that they do come in a 185/60 size too. Thought they only came in the 70 ratio. I'll do a bit of experimenting to see how low I can go before rubbing becomes a problem. Currently it is only at full lock when manoeuvering so not a big deal. They also make the gearing spot on for longer circuits like Silverstone and Spa, getting very close to the rev limit in top at the end of the straights. Turns out that 6700 in top with the 185/70's is nearer 121 mph. Was nice to actually pass some slower cars on the straights!
xkfeng7
Posts: 31
Joined: Mon Aug 13, 2012 3:33 am
Location: Boston, MA

Re: Birkett 6hr

Post by xkfeng7 »

Charles,
Thank you for posting your on-track exploits.
I, for one, really enjoy reading them. They provide inspiration for me to dump copious funds and time into my W11 so I too can enjoy driving it fast and safely on a track.
John
jonclancy
Posts: 942
Joined: Tue Nov 01, 2011 9:30 pm

Re: Birkett 6hr

Post by jonclancy »

Same here - love reading these report. Thanks for taking the time to post them. 8-)
Post Reply