Ultima GTR Bob's Ultima Site

Home | Links | Contact me
The Build (2003/4): June | July | August | September | October | November | December | January
Updates: 2004 | Le Mans | Sold | New Project
GT3 | Becker TrafficPro Install

Latest

Sunday 4th January

No updates for ages! Bit of catching up to do. First of all a I had a trackday - it went pretty badly so I lost a bit of motivation which partly exlains the lack of updates. I went up to Oulton Park on Friday 19th December. It was a cold, damp day, and I had a very early start as it's over 170 miles even going via the A roads, further still by motorway. The A49 is lovely in places but most of the time I was stuck behind traffic in the dirty sprasy. It didn't rain all day, but the roads were just damp and by the time I got there the car was absolutely filthy! Still enjoyed the drive though!

I'd just missed the start of the briefing so had to wait a while. I was hoping the circuit might dry out in the meantime with a few cars going round - I'd heard 4 cars had gone off in the wet on the trackday there a week previous. After a quick noise check (106dB limit) I tentatively edged out onto the circuit. It's a lovely circuit, but quite complex and scary in a 450+ bhp rear wheel drive car in the damp conditions. Lots of use of the indicator letting the other through, then on my second lap I was braking fairly gently on the downhill for the Knickerbrook harpin when the car suddenly spun. No harm done as I came ot a halt still on the circuit but I was pretty surprised and not very pleased!

I did a couple more sessions, then took Trev out for a few laps just before lunch. I'd started to regain a bit of confidence and was lapping a bit quicker when we spun again on the turn in to Druids. Again just stayed on track, but I decided that was enough! I'd promised a ride around the circuit to one of the other drivers, so I took him round a couple of laps very slowly. He then reciprocated and I had a few very quick laps in his stripped out and well sorted Integra Type R - cheers Ian!

I then headed home with my tail between my legs trying to figure out what was wrong - because the one thing I was certain of was that something was wrong for the car to spin so easily. As I enjoyed the drive home in the remaining daylight I came up with the following:

After chatting with a couple of folks since I reckon it's probably mainly the brake bias (so I've adjusted that), coupled with the heel/toeing - with the helmet on I had to slide down the seat a bit altering my foot's position on the pedal. I was also supplied Goodyear Eagle F1s on the front wheels and Michelin Pilot Sports on the rear. I know the F1's are a brilliant tyre in the wet as I've got them on the Evo, but I've no experience of the Michelin's.

After some thought since then I've asked a mate of mine who races GT cars for a living (Neil Cunningham) to come out for a test day at a local circuit to help me set it up right. He's back from New Zealand next week.

Here are a few pics of the car on its return - I'd actually washed the crud off the rear before leaving Oulton!

Yes, that is my GTR under there! Just after returning from Oulton Park (click for larger image)Another dirty picture ;-) (click for larger image)Who needs a wind tunnel? (click for larger image)Check out the mirror stem (click for larger image)Don't ya just love winter? (click for larger image)

Since then I've also tweaked the brake pedal position and think I'm now happy with that.

Driving the car around town has been a bit of a pain in the arse - it won't idle when it's cold, is OK when warm, but once up to temp it would idle for a few seconds then die. With the aircon switched on it wouldn't idle at all, ever. It was also very 'kangaroo-ish' round town. I'd read while building the car that a lot of the guys reckon it's worth removing the electric choke, so I tackled that this morning. The choke butterfly is simply clipped through a slot in its spindle, so that was easy to pull out, then the spindle could be removed. The rod from there to the choke mechanism is held on by a small split pin, and that was soon off. The actual mechanism was just held on by 3 cross headed screws, and once that was off I just taped up the supply wire and blocked off the vacuum tube which was attached to the choke. It was a good morning to test cold starting wthout the choke - just a couple of degrees above freezing. I needn't have worried, she started fine and just needed a little more prodding with the throttle to keep her going.

I nipped out to see a friend then and noticed the difference straight away - much happier idling and a little smoother wth less kangarooing. Very pleased.

On my return my next trick was to try tweaking the idle mixture screws. BEfore Christmas I'd received a nice book on Holley carbs and had had a good read of that. Although it was helpful understanding what all the different bits of the carb do the mian bits I need are sorting out the idle speed screw and the 2 idle mixture screws, one either side of the primary barrel. First job was to increase the idle speed to get it to idle! This is easy enough with the air filter off and it was soon happily burbling away at just over 1000rpm. After switching the engine off I turned the left hand idle mixture screw till it was closed - about 7/8 of a turn which was less than I'd expected. After resetting it to its previous position I restarted the engine and tried turning it anticlockwise, opening it out, and richening the mixture. The engine immediately picked up revs and smoothed off - I then had to turn the idle speed back down as it was now running at over 1500rpm. A bit of experimentation established the optimal position, and I then did the same on the other side, then fine tuned the idle speed. The car sounded much better, less lumpy than before.

Off out on a quick road test then. What a difference! Much better, much smoother with the kangarooing more or less gone, and a nice consistent idle at junctions. While out I tried the aircon and was amazed that although the idle speed dropped to about 700rpm it kept going without stalling! Result! Had to carry on and do a few more miles then since it was so much more pleasant to drive! :-)

Home | Links | Contact me
The Build (2003/4): June | July | August | September | October | November | December | January
Updates: 2004 | Le Mans | Sold | New Project
GT3 | Becker TrafficPro Install

Visits: 14814