Head

This pic is meant to show the ports, but we had trouble getting the lighting right so as it was possible to properly see the valves.

The inlet ports have been modifed to improve the average flow by 11%. Average flow was calculated by taking all of the measurements from 2mm-12mm of lift, adding them up and dividing them by 11 (ie the number of increments). The average of the standard head was then divided by this number and multiplied by 100.
The actual internal diameter of the ports wasn't increased greatly (only in the order of 2mm), but the actual design of the ports was significantly modified. A good portion of the gains came from this change in design. The rest of the gains came from modifying the back of the valves, blending the valve seats and cleaning up a few lumps and bumps.
As a comparison, the head on Mike Kojima's car (done by DPR in the USA) gained 15% over standard. A friend of his has managed 20%!! So we've managed a fair start, but there's still alot of development. :)

The exhaust ports weren't modified significantly and no flow figures were taken. The plan is to obtain a damaged head which can be experimented with over the coming year.

At this point I have to thank my friend Mark Banyard for his efforts in helping me with this head. It is his design which has got the head flowing as well as it is and his advice has been invaluable over the duration of the build up of the car.

The head is still using the standard Hydraulic Lash Adjusters (HLA's). Replacing the HLA's with a solid arrangement was looked into, but discarded due to time and/or financial constraints. We initially considered making a shim to fit into the original HLA body, but this was going to take more time than we had available. We also looked into installing GTiR solid pivots, but this would appear to have been a reasonabley expensive exercise. These pivots do not drop straight in and a sleeve would need to be made up to fit them. I'm unsure if a shim would also need to be put underneath them or not. Either way, we didn't pursue this option.
Another option was to import a "Lash Killer Kit" from JUN in Japan. At around $1400 this was simply out of the question for financial reasons.
Having spoken to Phil Ryle at BRS Motorsport, we have discovered that our original idea is the best plan of attack, if not somewhat fiddley. We may make solid lifters for this motor down the track (after checking how this will effect the cam with Ivan Tighe's), although this is dependant on whether there will be any worthwhile gains.

These are the new Ivan Tighe cams. The part numbers are 558C and 302C. I'm not dead sure of the specifications (the cams were chosen after consultation and advice from Dean at Ivan Tighe - after all he's the professional :) ). The inlet has around 290 degrees of duration, while the inlet has 280 degrees of duration. Lift has been increased from 8mm to around 11.7mm, at the valve.

The specifications we gave Ivan Tighe was that the cams had to work with a standard bottom end, they had to work with HLA's and they were to be usable up to roughly 7500 rpm (given the standard bottom end, factory redline would seem appropriate). The new cams should work from around 3500 - 7500, which is perfect.

Here's a pic of the profile of the cam. I wish I had a standard one which I could have included for the purpose of comparision, but both inlet and exhaust were done at the same time obviously. Anyhow, they are substancially different to standard.