Self centering steering - an IVA requirement

The IVA manual states:

"When the vehicle is driven at speeds of over 10mph, there must be a degree of steering self centring evident"

This is a difficult one to get right without driving the car so I used a local private road to drive up and down to see if I could best gauge what was going on with the steering. The consensus on various forums seems to be a small amount of toe out and much increased front tyre pressure.

I tried this, and to be honest the car felt close on undrivable with the front end feeling like it made no contact with the road!. Back to the drawing board, tyres back to 18psi, and a tad of toe out seemed to do the trick. What was really interesting was the amount of difference just one turn of the track rod made on the feel of the car. In such a light car the geo set up can really change the entire feel of how it drives. I remember getting my old westfield set up by track developments just before a track day, and it was probably the single biggest improvement in performance terms that I made.

Plan is to get through IVA, then take car to the specialists for a suspension set up. Currently, the front end seems to stiff, possibly because the car is built as light as possible, but will do for now.

Engine bay protection

One of the (what I think) major issues with the rear of the J15 is the total lack of any protection of the engine bay from the rear wheels. This part of the build is left to the builder. I thought long and hard about this and came up with more seemingly unfeasible ideas that I care to remember. A chance glance over a rear engined 1960's lola at the recent Goodwood Festival of Speed gave me the inspiration I needed. That used a nicely crafted aluminium wheel arch that sat within the rear clam shell.

Clearly I couldn't dream of panel beating some Aluminium like they did in the 60's, so I opted to use the remainder of some plastic sheets I purchased in bulk some time ago.

A large piece was bolted to the inner arch, and the inner part bonded using sikaflex and some additional aluminium brackets for strength. End result should see the engine bay kept a little cleaner. You can also see some of the aluminium strips I've put over the exhaust cuts in the hope that it avoids the fiberglass catching fire!.

In other news.........One item that has been bugging me was the front indicators. I purchased them ages ago, and they were not E marked. For IVA, this is not a must, but no E marking means the IVA man must measure the brightness etc, so I simply opted to change the indicators for some that were E marked...Job done.

Also, because I've used 13inch wheels, the front ride height was not quite high enough for the lights to achieve their 50mm min height, this has now been taken care of via some brackets on the front shocks.

Finally...IVA....It's the 13th Aug 2014 now, and I applied two weeks ago. The money came out well over a week ago, but still no date. I was hoping for an aug date, but it's going to be sept I suspect...Oh well!.

The final push

It's the the 7th July and I've still not booked IVA....I think I'm ready but....but....but what!. I should just bloody book it and quit with the excuses.

A few general updates.

Rear view mirror, now installed, it needs to be high enough to get over the rear engine. This should do. I madeit from ally, and grafted on the puma mirror.

Also completed was some water proofing to the rear, in an attempt to shield some of the grime from the rear wheels.

More on the vct system

Here are a few additional graphs showing the operation of the vct system in just an on/off mode.

• Run 3 is with VVT on all the way
• Run 4 is with VVT off all the way
• Run 8 is with VVT on up to 5500 and off after, plus final tweaks on fuel and
  ignition.

What really stands out is the additional mid range that it fills, and clearly the cam is capable of making power high up the rev range (normally compramised with the mid and low down).

Will try and writ some more on this interesting subject when I get chance.

Engine set up - Does VCT work?

Friday was a big day for the Sylva J15. It was time to get the engine tuned and ready for IVA.

I have used Northampton Motorsports many times in the past, and find them nothing but perfectly professional, pleasant to deal with and talk to and most importantly...bloody good at their job. You also know that the power you end with is real and not just beefed up pub fodder.

We kicked of at around 12:30pm, and the engine was all over the place. It would not idle, and there was something not quite right...we ended up tracing the issue down to a TPS sensor not allowing one of the butterflies to close, and the bleed screws leaking. Once sorted, we had a good tick over, and the car was ready for mapping.

Now, this was always going to be an interesting one. There has been many, many threads about the function of the variable valve timing system on the st170 and puma 1.7 engine. The system used by ford is continuously variable, but the Omex 600 in the J15 will only do on/off control. The question really is, will this work?.

The answer is yes, and it worked very well. Troy at NMS, did some power runs with the VCT fully on, and with it fully off.

• With it on, the tick over and first 2000 rpm were compromised, but mid range looked good, with power trailing off beyond 6000rpm
• With it off, tick over was fine, but the mid range was low, but top end power looked good with the engine puling right up to 7200rpm.

So, with these two plots overlayed, it was very clear where to turn the vct on, and where to turn it off again. This is done via the alt function in Omex, and also you can specify the throttle load, so if your are cruising gently, you can have the vct off.

Anyway, what was the result of all of this. Headline figures were a stonking 155bhp, but decent torque in the mid. You can see the plot shows the kick at 5800rpm, where VCT is disengaged. The curve is smooth, and the engine is bog standard apart from the Throttle bodies, and exhaust. so up from the 125 hp of the puma by 30bhp. Very pleased...I took the car for a sneaky drive down the industrial estate and it felt suitably fast. The next step was the emissions ...and with the addition of the CAT, it sailed through without any further alterations to the fuel map. All in all, a great day out :-)

Wheel arch protection and lighting

Not a massive amount done of late, but at least the rear lights are now completed and working. If you have been reading the blog, then you will no I opted not to use the lights that came with the kit for no other reason than I found the LED autolamps all in one units to be a good fit with style and ethos of the car I'm building. The LED units mean the drilling and mounting is easier as they sit on the fibreglass rather than poking through it, it also means the rear of the lights are less exposed to the inner wheel arch environment.

The fog, reverse and number plate lights are also LED, and suitably bright as can be seen in the pic below.

Other additions to J15 include some font inner arches to at least 'try' to keep the inevitable road grime away from the rest of the car...quite how effective this will be remains to be seen. I actually made them from the same material they use for most production cars. It's a plastic which is bendy enough to go around corners, lined with some rubber finishing strip. It's simply bolted into the panels that close of the end of the sills. More of this stuff needs to be strategically deployed around the car, but all in good time.

 Last but not least for May 2014.....what car would not look complete without a huge black dot on the side!. Number to be decided.....might put my age when I finished the car!

Next step...wire font lights and rolling road.

Stripes

The stripes are done!. So basically, this is how the car will look (apart from perspex headlight covers). I think the three way stripe looks good. The application was 'fairly' straight forward once I actually figured out that the soapy water method of fixing was indeed the best way to do it.

Of course, this should have been the last job, but it's yet another distraction from the lights wiring :-)