Skoda Rally Blog

Today was the day I’d booked the car in for a run on the dyno at Veysport – Andy who was at Triton (who mapped the car in 2008) now has his own business in Verwood, so I booked time at 3pm.  In the morning, I did a few things on the car including changing the brake fluid and bleeding them, and then started up and went for a drive.  And yet again, problems.  The car was running as rich as hell – about 10:1, instead of the ideal 13.5:1.  I limped back home, and started checking, and found that I’d made a mistake before – the standard fuel pressure regulator actually ran at about 3.75 bar, not the 3bar I’d seen at rest.  This explained the “rich as hell everywhere” I was experiencing.  But didn’t change the fact that I had a car which needed to be finally mapped at 3pm, only 4.5 hours in the future.  A quick bit of research and it looked as if a 10% cut in fuel would return things to normal, so I put this into the map, and the car still wouldn’t start – I’d spent too much time turning it over before realising that the ECU connector (whose design I have always hated, Mr DTA!) was half off, explaining the total lack of firing, and now the battery was flat.  G-reat.  Put it on charge, walked away for a bit.

Half an hour later I put another battery on via jump leads as well, and gave it a go.  10% was clearly too lean, the car started, but spluttered a lot, so I re-set it to 5%, and the mix looked a lot better.  Went to drive down the road, but it was spluttering and backfiring in the exhaust.  Really odd, given that the mix looked spot on from the O2 meter, so I persevered with it, and it cleaned up after a mile or two – it seemed that the plugs had got fouled and needed a bit of time to clear.  By 5 miles it was running sweetly, even ticking over.  I then realised that the brakes were much better after someone did a stupid move in a traffic queue right in front of me!

But would it last?  A couple of starts later on seemed to indicate that it would – so hopefully this is a case of oversight rather than an odd problem rearing its head again.  Tammie came over (originally we’d planned to go out), but given the lack of time we settled for Pasta, as I had to go to work before going to Veysport.  This gave me the opportunity to let the car cool down again (it restarted fine after 90 minutes), and also drive a bit on dual carriageway and do some overtaking on the way there – it seemed to be going OK, and unlike the last engine seems quite willing in top gear to overtake.

Once I got to Veysport we hatched a plan – last time showed that a lack of cooling on the dyno wasn’t great for the engine (and particularly the oil pressure) so we decided to do a power run, check the fuelling with a run or two more, and then see if there was anything to come from advancing the timing.  However, given what happened the first time on the dyno (with a dodgy engine, but you still feel nervous) I was not particularly calm at this point; a disaster now would mean game over, realistically.  Andy got the car on the rollers, had a good look about, and then did a power run.

In between runs...

I was pleased to see bigger numbers than last time, already.  The fuelling was a bit off (slightly lean), so we put more in and did another run, getting slightly more power and ironing out a bit of a flat spot, but with a spot on mixture throughout – so my preliminary work with the LM-1 had really paid off (not only in terms of money but more importantly giving the engine an easier time).  So it was time to adjust the ignition timing; I didn’t realise just how critical it was; Andy explained that half a degree can make or break the power an engine makes (perhaps seeing an extra 5 bhp), so we dialled in extra advance and did another run; there was no difference at all in the power, so clearly things were set correctly already (no detonation, but there’s no benefit in having more advance than you need), so we dropped it back and did a final run.  The end result:

OOh, nearly there...

Not quite the 100bhp I’d wanted, but damn near it.  The shape of the curve is interesting – the drop at the end is the rev limiter cutting in; and rightly so – 7000rpm is the safe limit for the engine components I have, but there’s clearly a LOT more to come if the engine could rev higher, as you can see from the line the curve is following at that point – the head and manifold clearly can flow a LOT more gas than the previous engine; unfortunately steel rods and forged pistons would massively increase the budget, and also steel rods wouldn’t be legal in Group A, alas.  But the engine feels good to drive, and is making more power than the previous engine did at peak for over 1000rpm, which is good. I’m sure there are people reading this who think that 100bhp is a joke, and maybe it is, but it’s going to be a big improvement on the stages; I’d love to have 130bhp or so, but it’s going to be good enough (hopefully) to go quicker than before.

So, with that done, it was… done!

After the work, time for a rest.

The drive home was thankfully uneventful – there are a couple of flat spots I need to address (which are best done on the road, as they’re dynamic things), which I can do tomorrow or on Sunday.  I need a break, but it finally looks as if nearly everything is done.  Nearly.  Still to do:

• HANS device – I’m still waiting to hear back about the one I am borrowing for Paul
• Helmet for Paul – despite paying for it over 2 weeks ago, it’s still not arrived.  Yes, I’ve chased the seller.
• Tyres – these look to have been sorted, I just need to arrange collection for them, but they should do the trick.
• Stickers – these should be coming tomorrow – the eagle eyed will notice I’ve taken the “Sponsor this car…” off, as it’s too late now (aside from a late eBay auction frenzy, with 4 spaces up for grabs on the car)

I think that’s it.  And I know I need a day off!