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Morning all, I was down at BLiNK yesterday for one of their tune-up packages: http://www.blinkmotorsport.com/tuneup.html. My car had felt a little 'tired' last season so following a bottom end rebuild I thought it was time to make sure all the wheels were pointing in the right direction and that my workmanship hadn't let too many ponies escape! Arrived nice and early as this service takes pretty much a complete day, had a quick chat with Fraser while Richard was geo-ing a 4x4, then unloaded my car ready for the shocks to be removed. Part of the service is a shock dyno, where the dampers are removed and fitted to a testing machine which actuates the shock through a wide range of conditions and measures the resistance produced at both low and high speeds, and during compression and rebound strokes. At the very bottom of the rig (you can just see it here) there is a crank eccentrically attached to a motor-driven disc, so as the motor spins it compresses and extends the damper. The measured load on the motor is recorded and some lovely colourful graphs are made The idea here is to make sure the damping characteristics across each axle are matched - it's rare to find a pair of dampers that have the same curves! If they don't then the car won't handle optimally. A good example is my pair of rear dampers - to get the two plots below, one is on 11 clicks and the other on 15! It was a similar story up front, with a 2 click difference. The curves show a 'classic' 'decent' road damper shape. I'll try to explain... X axis: Speed of damper movement, measured in inches / second. Up to about 3"/s is what we call 'low speed' and over that (the machine tests to ~7"/s) 'high speed'. Low speed is kinda split into two, and these are the sort of speeds the driver feels. The first part is the resistance felt under turn-in, and the second part is a little faster damper speeds such as those when hitting the brakes or mashing the throttle. High speed applies to things like hitting kerbs and potholes, where the wheel has to move out of the way quickly. You can clearly see the 'knee point' where the damper switches between the two circuits on the lower part of the trace about 1/3rd of the way along the X axis. The other small 'kink' in this line is the split between the 'turn in' type and 'braking' type of low speed damping. Y axis: This is the resistance produced by the damper. Positive Y here is shown as compression damping, and negative as rebound damping. We need more rebound damping otherwise the car will be 'crashy' and not have good body control (the springs are trying to extend the shocks so we need to control this or the car will be bouncing along the road / track!). A normal ratio is 2:1 which these dampers exhibit (if you follow across from the 'corner' about 2/3rds up the y axis, then trace across horizontally from here, that shows you the split). The red trace shows my driver's side damper on 11 clicks, and the yellow trace is the passenger side on 15 clicks! All 4 dampers were tested in the same way and I have been supplied with full charts of all the curves from around 7 to 15 clicks on each of them, allowing me to tweak as I wish in future and still make sure they are matched. Next up - the scary bit. I'd never rebuilt an engine before so decided to go 'in at the deep end' and choose this year's race engine as the guinea pig, haha. It's always a bit nerve-wracking having any car on a dyno, but one that you're re-built is even worse, especially when the revs start to rise for the first time! I won't go into the details of this, as I have covered it in another thread, which can be found here: http://forum.wscc.co.uk/forum/index.php/topic/100595-a-good-morning-at-blink-motorsport/ The main thing people will want to know is what power the car made. Well, not a lot - a smidge under 91 at the hubs. However, this is pretty much what I was expecting and it ensures it's legal for our race series which has a 130bhp flywheel limit on the Autotronix rolling road. There has been quite a lot of chat about power in MaX5 (our race series) and we now have Nick from Skuzzle Motorsport joining us with his rolling road at a couple of events each year to try and make sure it's a level playing field, and any competitor found to be in breach of the maximum power will end up losing their points, so it's just not worth going over... I did some digging in an attempt to work out where I'd need to be on BLiNK's dyno and I guesstimated 92bhp at the hubs having found Steve C's from MX5Nutz's thread about his Mk1 that did runs at both Autotronix and BLiNK with the same spec engine. http://www.mx5nutz.com/forum/index.php?showtopic=87292&p=1392468 http://www.mx5nutz.com/forum/index.php?showtopic=87292&p=1433705 Steve's car made 140 corrected flywheel bhp at Clive's and a bit over 100 at the hubs BLiNK - which on both counts is 25 more than each operator tests a standard car at - so to be 130 or under at Autotronix I'd guesstimated 92 or less at BLiNK ((100 / (140 / 130 )) = 92.8). Anyway, here's Richard tweaking away - one eye on the oil pressure gauge as it was reading pretty low at one point! The oil seemed to take a while to settle, when the car went on the dyno it was a bit over max, but after a couple of runs we got another ~600ml in there and the oil pressure went to a more sensible level - phew! And here's the final graph after a timing tweak (around 10 degrees now, it had been set to 4 all last year!!) and a couple of clicks on the AFM. What's nice is that it makes max power early and holds it, so I have a good 'area under the curve' and there won't be a lot of drop-off in power following a gear change. A good Mk1 1.6 race car will make at least 100 hub bhp on this dyno, so I'm way short of that, but that sort of figure isn't legal for our series! After that was done, we moved onto geo and corner weighting. I'd been doing it with bits of string and some Tesco bathroom scales all last year, so this was a little more advanced : Didn't get chance to find out for definite how close my efforts had been as we'd had the shocks off and ended up raising the ride height before the geo machine was turned on, but it looked to be pretty close - certainly 'good enough' for a newbie racer who had more time to gain from driving the thing than getting it set up. Here's Richard tweaking away - nice big screen on the floor under the car so he can adjust 'live', makes it very quick and accurate! Corner weighting worked out nicely, we finished with a perfect 50.0% cross weight with minimal fuel, and it appears my winter diet has gone well as I need about 4kg of ballast to make the 970kg minimum weight now! Well, that's it. I had a thoroughly enjoyable day, learned some new stuff, and the car is now in tip-top condition so I've got no excuses this year As expected, the service from Richard, Fraser and Adam was superb, and I felt the value for money of this service was excellent too. I pretty much had a full day's worth of labour from 2.5 people (Richard and Adam were on the car all day and Fraser kept popping over to add some pearls of wisdom here and there) using some very expensive and accurate equipment, combined with lots of handy advice gained from many years of racing and preparing MX-5s. Well done if you read all this Cheers! Adam

Tried 3 Ironmongers and B+Q to buy a 7mm box spanner. Last resort was Halfords. " We dont stock 7mm only down to eight " said the salesman. "Typical I thought " "Whats it for ? " he asked. " Its to get down a hole " I said. "Hang on and ill have a look in my toolbox " He reapeared holding a brand new 7mm job. "You can have this cause Ill never use it " What a great guy and he wouldnt even accept payment. Jim was his name and he is a hero. Thanks Mate.

Yes you can. Just shout if you've not quite got the pm big figured and we'll guide you through it!

It should be as Blue Ass Fly posted Stephen...if the tester follows the information in the manual properly. The car should have an emission test according to whatever is the oldest - car or engine. Or wording to that effect

This morning, Jim has just come across a job where he needs a 7mm box spanner!

Yes I am too but my first ever event will be at Gurston, so 64 for me. I may come down to Castle Combe as a spectator.