Handling Issues explored
Rather than running backwards and forwards to Abbott Racing for tweaks and tucks it’s time to bite the bullet and buy in the kit to set the chassis and suspension up in the workshop.
Laser wheel alignment kit ordered.
Camber calliper and level gauge ordered.
Brain resting ready to start the learning process, as if there hadn’t been enough learning building this beast.
Damper settings and tire pressures have been checked and adjusted ready for the next phase of testing, once the new kit arrives.
With the cambers checked and matching exactly the figures set by Abbott Racing the next checks were the the toe figures. As the fronts had been moved for the IVA test the rears were checked until the laser gauge could be used repeatedly to give the know good result.
Laser Wheel Alignment Kit
Camber & Caster Set up Tool
Using these tools, after some practice, ended up being very simple and amazingly accurate. Not only that but setting up the car became reliably repeatable. Once comfortable with the kit making changes, testing and resetting and/or adapting the settings became logical and gradually the car became more stable the main obstacles were testing time and testing weather rather than the alignment kit itself.
From a twitchy nervous car the beast was changed into a rapid turn in handful of a car. Yes the seed of turn was at some point was beyond quick and just damn right terrifying. But you have to give the whole package high praise indeed, even in these hairy moments the chassis remain poised and the grip held firm, allowing normal service to be resumed without visits to the undergrowth.
During the initial set up process confidence in the car grew very rapidly, yes there is much work to do but when you realise that even when you get the set up horrible wrong the fear is more likely to total the car that the car is. Quick throttle, steering and brake control by any competent driver will see the machine safely to a halt. But there’s the trick, don’t try to get it all back and carry on. Get it back and bring it to a crawl and all will be well. Simple when you think about it, if the set up is wrong you are not saving the car from you lack of talent, you are saving the car from itself. Go home figure the problem, change the settings and try again.
This is going to take some time and I can bet my dog on it that no two cars will ever be the same.
PS this is a VERY cool car 17 pictures taken so far, 7 of them by very hot women. I think I’m in love with testing.
Spring 2013 Major Testing.
After lots of winter mods to the bodywork (some still ongoing), lights etc. Spring weather final arrives after a dreadful winter that seemed to go on for ever. So time to go out and push the limits of the handling.
Well that didn’t take long. Grip levels are fantastic and the chassis behaves without issue. The suspension needed two notches firmer front and back after the rise height is lowered by 10mm. The major problem to solve is
1. Right hand turn in is quicker that left hand turns.
2. Corner stability is not good. Long test corner at 65MPH is fine to start with but touch the steering and things get scary. Anything above 65MPH and the whole package becomes unstable.
3. Steering self centre (and old issue) is not good at all.
The answer to problem 1 was a rear end issue. The offside of the car had a slight toe in as compare to the nearside of zero toe. A pair of 0.125mm shims sorted that issue. Now the turns are equal and just corner stability to sort out.
Solving issue 2. Was not as simple to sort as everything checked out perfectly setting wise. Nothing lose no matter how rigours the steering, suspension and joints were levered, pushed and pulled. So back to the drawing board with the front end settings. After a few hours adjustment and testing and lots of thinking and head scratching the answer came. An increase in toe in at the front end. An extra 0.25mm on each side solved the problem perfectly. Not only that but the mild tram line issue vanished. And as an extra bonus (which still puzzles my little grey cells) the steering self centres much better, in fact better than it has ever done. So tick off item 3. as well.
The car now drives very nicely indeed! Normal road manners have been dramatically improved and high or low speed hard cornering is exciting for all the right reasons. Driving into my favourite test long corner at well over 100mph (honestly was not looking to closely at the clocks) and the car smoothly tracks the path plotted by the pilot. Wonderful fun!
So time to finish all the bodywork changes and then time to start ramping up the power output. Now the car can be trusted under all sorts of extremes road going power upgrades are safe to try out.
Now driving with a constant 280BHP the cars limits can be quickly found and are, to say the least, alarming! The car is either on perfectly on track round a corner or either in the hedge or facing the wrong way. The break away point between grip and a spin is knife edge. In other words there is no handling as such, there is either grip or nothing. After much testing and much new underwear the problem has been traced to the rear end. While the front is point and shoot and the steering is responsive and light (well for a car with no power steering) the back end can be lost without warning.
First we find the famous Nylock nut problem, that of a coarse thread that is long causing the nylon to become tapped and hence no longer a self locking item. Not uncommon in my everyday work so no surprise to find the lower rear uprights with play due to this issue. Quickly tightened and and extra lock nut deployed and that is the end of that issue.
Great me thinks but no says car! Now the point at which things go can be sensed but still absolutely no chance of catching the little beast. Again it is all rear end, the beast is behaving like an early widow making 911. Double checking the toe proves everything to be perfect. So time to check the camber. Nothing to see here but maybe this is the area to experiment as the feeling is the toe of zero at the rear is good. So the settings are changed and gradually the car becomes more and more predictable. With settings of negative 0.75 degrees a “WOW” moment is reached! The car can be almost drifted into a corner once the grip has been lost. The tires are not happy but their pain can be controlled and the car can equally be controlled and directed back to the sane side of the road. The green green grass can be left for the tourists to admire.
Powering out of a corner is now also a pleasure. Rather than a series of quick adjustments its more of a smooth procedure with one or two tweaks to keep everything on course. Very pleasing and as Mr. Celica and Mr. M3 and MR2 found out today extremely quick. MR2 needs a wheel arch wash after visiting embankment (maybe a butt wash as well). To be honest it was far too easy, the Otage never even hinted that it was more than a little stressed let alone on the ragged edge. But hey it made me look good and that’s a first! Up to now I’ve looked the fool as I clean off the mud or do a three point turn, so all in all a very very nice day.