Calibrated the speedo and AP22 using GPS and coastdown tests. The speedo is over-reading by just 2% which is absolutely perfect. The AP22 magic numbers are cD x area : 1.02, Rolling resistance : 0.017, which was slightly out from the guesses that I had put in.
I decided at last to pluck up the courage to tweak up the boost levels today, as advised half a turn on the actuator rod causes about 0.05 bar additional boost. 4 turns took me from 1.1 to 1.3 bar, peaking on overboost at between 1.5 and 1.6 bar. Held boost is still a little below what I could/should run but I would want to re-work the boost pipework before doing that. There's no point putting more heat into the air by cranking it up when removing obstructions from flow will do the same job without heating things up.
Out on the road there's noticeably more oomph but the acceleration does seem pretty constant from 3.5k upwards. I did quite a few test runs, partly to test the charge cooler water temperature and partly to make sure there's no gremlins hiding still. Accelerating 30-70 in 4th, braking *hard* back down to 30 and then repeating a dozen times gives me a lot more confidence in the electrics and brakes, after a few runs I was even getting flames out of the exhaust on overrun!
Pulling in to check the temperatures the brakes were smouldering nicely which gives some indication of the energy that they were having to disappate. As I walked up to check the water temperatures I thought it a little odd that could see the bottom hose of the turbo through the bonnet slats. The water temperature was a little above ambient but remarkably low really given the circumstances.
As I got back in the car it occured to me that there's no way that I could have seen the bottom turbo hose, what I was actually seeing was the manifold and exhaust glowing red hot. I was a bit taken aback to say the least, I know it happens when you're dyno testing flat out but I was staying 1250rpm below the red line, it wasn't continuously running at that speed and there was a good minute between the last acceleration run and me being able to pull over safely.
I don't think that I need to worry, since on inspection the bonnet and all surrouding components were cool, which seems to indicate that the heat shielding is doing a fine job. I am inclined to believe that I really should look at replacing the 4x4 exhaust manifold with a 2WD one. Doing that would even up the primary lengths and ease the flow, particularly if I converted to a bonnet exit exhaust as fitted to the Dax cars.
In other news I finished making up my tracking gauge and the front end at least is parallel, I need to drill a couple more adjustor holes before I can measure the back end, since it's slightly wider at the rear than the front.
Prepared for a trackday at snetterton tidying up lots of loose ends.
Well what a day. The hotest of the year so far, with temperatures in the mid 30s everybody and their cars were feeling it. Luckily the westfield behaved perfectly. Water temperatures topped out at 90C on the track but the mobil-1 gets a bit thin when it's hot, changing over to the castrol RS 20W60 should sort that though.
The chargecooler worked brilliantly, 30C down on the old intercooler setup and the system is very much limited by the size of the pre-rad. This means that just by increasing the size of the oil cooler I will substantially lower the temperatures, releasing more power. The question though, is whether it's better to just put a larger oil cooler on or if a more radical approach, perhaps making use of side pods is the way to go. The other thing I want to do is to modify the inlet to the chargecooler and that side of the piping to improve the airflow.
The circuit though is lovely, powering past Evos and Porches on the straights was pretty memorable, as was lapping most people at least once during a 20 minute session. I was finding that by half way along the straights I was up to 120mph and was easing off - going fast in straight lines is only so much fun, it's the twisty stuff that it's all about!
The final bit of excitement was meeting the first owner (Martin Raybould) of my car back in 1995. Apparently Westfield couldn't solve some cooling problems back then, which is why they bought it back off him. Seems like they weren't really trying to fix it if you ask me, big radiator, lots of heat shielding and proper venting is all that was needed.
Oil and filter change and a general check over of everything post trackday. Catch tank had some, but not a huge amount of oil in it. All the sensors check out and all the hoses are ok although I tightened up the ones coming out of the turbo and added a jubilee clip onto the breather overflow onto the catch tank. Plugs all looked good as well so the car has a clean bill of health. I did spot a small amount of movement in the thottle linkage, which I'll look at over the weekend. I still want to check levels in the diff and gearbox though.
Stripped down the throttle body and rebuilt it to address the play in the linkage. Despite this there's the idle still becomes erratic from time to time and it's beginning to look like a sensor related problem. I can't believe that it's the idle valve since that's been in place for just a couple of days, the lambda probe would be my next guess but the plugs all look good, next stage is to borrow another IACV and eliminate that from the possibilities.
With the aid of an IACV borrowed from Steve everything else on the engine is proved to be ok. Finally worked out a cunning way to add a throttle stop by making use of some L section aluminium attached to the cable bolt. Drilling a number of holes in this at different offsets allows some adjustment of when it makes contact with the bush on the brake and clutch shaft.
Decided to re-engineer the chargecooler header tank mounting to bring it up another inch or so to help bleeding and raise the effective water level, thereby allowing me to run with more water. Stripping down the front end of the car to gain access takes an age but it's a job worth doing.
Finished off refitting the header tank.
No updates for a while since I've been too busy enjoying the car in the fine weather to do much work on it. The odd few things I have done are to tighten up all the nuts and bolts to make sure everything is still to spec and to cure a few little rattles. Theres been a further modification to the breather system and adding a couple more layers of fibreglass to the passenger side wing to try and stop it wobbling around.
Work is now focussing on removing the last couple of noises and to further improve the practicality. To this end I'm embarking on some new sidescreens to replace the original ones, the intention being to improve visibility by making the top half from solid lexan/perspex, to improve interior space by curving the lower section out and finally to improve comfort levels by increasing the height by an inch or two and increasing the length further towards the rollbar. The initial cardboard mockup of the lower half is showing promise but requires a lot more work before I can move onto the next stage.
| Previous | Next |
| G2 home | Chris' homepage | Westfield | Westie Rebuild |