Tuesday, 27 August 2013

Whiskers & Messing with the fuel Map

When I did the gelcoat repairs to the nose after removing the standard front indicator stalks I wasn't 100% happy with the finish.  There were very small bubbles at the surface that wouldn't polish out that filled with polish leaving white spots that then needed further polishing but few people noticed without me pointing them out and I fancied fitting Caterham Whiskers (or Canards) in the future.  Having searched for the Whiskers I could only find them for sale with Demon Tweeks or direct from Caterham at around £80 a pair which was a little too much, even with my inability to resist temptation, so they were put on hold.  I looked again at Stoneleigh and Aerodynamix said they might be doing them in the future so I spent my (non-SWMBO traceable) cash on replacement carbon fibre wing mirrors. After my first track day and some hot running I was looking around for ways to reduce the temperate of the air under the bonnet that feeds the TBs by some form of ducting from one
of the bonnet vents when I got distracted and found these:

They arrived in the post today so I spent sometime in the garage trying to work out how & where to fit them - ended up like this.

Next on to the popping and banging on overrun, I'd exchanged emails with Troy at Northampton Motorsports to ensure that I had the TB setup correctly before I go for a rolling road remapping session. He advised that if there was insufficient fuelling at low load below ~3,500 rpm there wouldn't be a stoichiometric mix, hence it wouldn't ignite in the cylinder and would be pushed into the exhaust where it would collect and ignite hence the popping & banging.  The potential solutions were to either increase the MS/B setting or adjust the individual setting on the fuel map.  The MS/B route was the most straight forward but it worked as a single scaling factor it would affect the whole map increasing the fuelling. The fuel map changes were possible without a RR as it was only the low load elements that were being changed.  The screen print below shows the changes in the map in light blue, when the software is running you get a bulls eye graphic and indicators on the table that change colour with green indication that the map was in the right area.

Out on the road the changes were immediately obvious, once the car was warmed up there was almost no popping and only when decelerating from rpm than were greater than the changes that I'd made.  I now think I'll leave it until I can get to NMS possible early next year before the late spring/early summer.


Saturday, 24 August 2013

Devon Blat

One of the Dorset WSCCers, Colin, actually lives in Devon but travels 120 plus miles each month to attend the pub meet and is always first to attend track days and weekend trips - he's even become keen on sleeping under canvas after Stoneleigh 2013 - maybe not.

Anyway, Colin and his better half Pat invited all the Dorset WSCCers plus some of their Lotus and Westfield owning friends down to Dorset for a couple blats and a BBQ.  Some of the crew made a weekend of it and booked B&Bs but as my 3 teenage children needed to be parented Tricia and I were limited to the primary day on Saturday.  Unfortunately parenting duties expanded which meant that Tricia had to stay at home so I left at 07:50 to meet up with Malcolm, Dale, Brian and Mrs Brian at the Honiton services on the A30.  As it's only 2 months and 1 day since my myocardial infarction I declined the bacon roll enjoyed by the others and limited myself to a polystyrene cup of tea.  Once refreshed we headed off to Dawlish to fight with the Bank Holiday and Air Display traffic on our way to Colin's arriving just before 10:00.  Pat was manning the kettle and dispensed teas and coffees as the posse assembled on the drive - eventually 6 Westfields, a Lotus 7 and Elise.  After Pat had handed out the laminated pace notes (where's Tricia?) and the photographs, we headed off - Westfield style - to the fuel station! and then off to the greater Devon.

5 wise men and a Lotus 7
 A well planned blat with a mixture of A, B roads and dual carriage ways saw us heading North then West skirting Dartmoor National Park before arriving at Tavistock for Lunch and the Cheese Festival.
Not high speed dodging vans


Once refreshed, fresh crab sandwich and Devon ice cream for me, we headed East through the middle of Dartmoor.

The line up
Then South back towards Dawlish.  Unfortunately I had to get back to Yeovil so headed East when we got back to the A380.  Hopefully the BBQ will be a success and tomorrows blat will equal todays.

Many thanks to Colin & Pat for organising today.  I covered over 200 very enjoyable miles

Saturday, 10 August 2013

Playing with the throttle body setup.......

I had trouble setting up the TBs when I built the car but drew stumps when I got the setup good enough to pass the IVA emission tests.

I've now driven 3,000 enjoyable miles in the car but have never been confident that the setup was right.  My concerns are: 1) lots of popping/banging when de-accelerating especially in 3rd or 4th gear. 2) Judder when in 4th or 5th gear when driving through 30 mph zones with no throttle - clears when accelerator is used but requires running in 3rd gear to stay in the speed limit. 3) The idle appears to be slightly high at ~1,000 rpm when the ECU was set to 900 rpm

When I setup the car originally I set the TBs at 4.5 kg/h having closed all the idle by-pass screws but the left hand inner TB which was 1/2 a turn open as advised by Guy at Omex as the starting position.  Once I'd got the TB balance the TPS reading was 11 and Throttle Max 195 so I set these in the ECU calibration.  Guy at Omex said that 11 was too low and suggested that I should adjust the TPS to give an idle reading of ~20 but having achieved the IVA emissions requirement I wasn't prepared to do anymore.  Mark at Westfield also suggested that the problem with the driving in 30 mph zones might be associated with the ECU switching off the fuel and that he sets the factory cars at 4.0 kg/hr.  In addition, Terryathome's video suggested that all the by-pass screws should be closed as the starting point for balancing the TB.

I followed T@H's initial setup and balance the TB's at 4.0 kg/h.  Once I'd done this the TPS was still reading 11 so I adjusted the TPS until it read 21.  I then set the ECU calibration file to the new idle of 21 and Throttle Max of 200.

And the results........mixed.....the judder has gone and the car is much nicer to drive through town, the popping/banging when de-accelerating appears much reduced but has not gone completely and the idle is now around 900 rpm so all three of my issues have been solved or improved.  However, I've also noticed that the car is now slightly hesitant when accelerating from lowish revs in 3rd and 4th gear, less of a problem than the previous issues but not ideal.

Time for a trip the NMS, so I need to start saving my pennies.......................