Art,

I would love to. The mock up should be done by this Friday. However, final completion is not looking good. Once the engine is done we still have our hands full. Not only do we have the barrel throttle bodies to prefab but we also have the combination chargers to locate, prefab the piping, three way bypass valve and coordinate with the ECU.

This setup will make the motor respond more like a normally aspirated motor. We should see some nice boost around 2000 rpm's with a lot lower induction air temperatures while utilizing smaller IC's. The good thing is the turbo's will be taking over somewhere around .6 bar and should never see more than 1.2 to 1.4 bar although more would be available but probably not necessary.

Will have more details later.

 

Nice write up Chad. When do we get to go to Norcal to meet with Sharkster? What happened to that event?

 

I like the sound of that:P

 

I should have a better idea this Thursday after I talk to Neil. It is still going to happen, hopefully in early November.

 

The mock up is complete. We have one item that does not fit ............ the timing chain. We are having another timing chain made that is one link longer. Other than an added expense there is a good side to this. By having a chain with an extra link we can make the shim a couple of mm's wider than 2.5 mm which in turn will allow us to make our rod length a couple of mm's longer. We are not just adding a link to an existing OME chain, we are having the manufacturer make a chain one link longer.

I believe the new rod length will be 132.0 mm's.

I know some of you will be asking us what that does to our time schedule. It will take four weeks to get the chain. In that time period we will also get the rods and pistons.

 

...and then in about mid September you'll start the build? I'm anticipating some very excellent results soon!

 

OK ............ things are really getting loosey goosey. We have made a decision and released the remaining parts for immediate production.

Here is the letter I recieved from Neil. I'll explain shortly what route I choose and why. I'm told all parts will be in within four weeks.


Chad,

We have finished all of the moch up we can do regarding the Chain length and spacer. The only moch up that has yet to be done is the Piston to valve clearances, but this will all depend upon what length Rod we use.

Stock Chain length, (116 links) with 2.50mm spacer

The Chains are too short and the Cam gears will not go over the camshafts. The Chain Rails are not in contact with the Chains as the Chains are too straight.

The only way this configuration could work would be to make new Cam drive Gears. The Intake Cam gear would be fixed and the Intake cam would have no electronic adjustment. The Cam timing would be fixed


Chain length 117 links.

This will require the spacer under the Cylinders to be 9.44mm. This will allow the Chain to be in the same attitude as the stock Chain lays and against the Rail. However the Chain does change angle from the end of the Chain Rail to the Exhaust Cam gear. This is not an issue. The issues will be, The Cylinder Liners will be too short when the Piston is at BDC. Once the Liners are moved out by 9.44mm the longer stroke will require the Liners to be longer keeping the Piston in the liner at BDC. Secondly, the Head studs will need to be longer.

Use the Stock Chain with 2.50mm spacer.

This will require shortening all of the valve lengths and removing material form the Cam Tray face that bolts to the Cylinder heads. This is not a viable option. The Cam Tray does not afford any material to be removed where required.

What we need is ½ of a link in the engines present configuration. This is not possible. All of the Rail mounting points need to be changed. ½ extra in length would give us what we need, but again the Cam gears will all need to be changed and the Link lengths and Gear teeth ratios all need to match.

Another option is to use the stock Deck heights and shorten the Rod length. The designed length was to be 132.00mm. We will now have to shorten the Rod length to 129.25mm. The difference is the 2.50mm spacer and the 0.254mm gasket required on each side of the spacer. Now we will use 1 gasket as per stock configuration. This rod is still 2.25mm longer than stock, with an additional 6.00mm stroke.

Neil

 

I didn't want to go into a major delay redoing liners and head studs. Plus the unknowns of the far longer liners and studs. The best option appeared to be going to the stock Deck heights and shorten the Rod length. The designed length was to be 132.00 mm. We could shorten the Rod length to 129.25mm. The difference is the 2.50mm spacer and the 0.254mm gasket required on each side of the spacer. Now we will use 1 gasket as per stock configuration. This rod would still be 2.25mm longer than stock, with an additional 6.00 mm stroke.

This would suffice, however I wanted to do better. Our current variables were the rods and the pistons because they had not gone into final production. The stock 996tt motor has a rod to piston ratio of 1.6+. The above solution would render a 1.57. If we had to, we could go with the 1.57 and it would work, however I want a better angle for our 6 mm over crank setup.

What can we do. We checked with our piston manufacturer and determined there was another .250 mm available by moving the wrist pin upward. I also remembered the old racing trick of offsetting the piston wrist pins off center. This procedure provides a better centering of the piston which amazingly makes more hp. I remembered what we did with the crank with the smaller journals (about 2 mm smaller for the NASCAR oval bearings) where we picked up a free 2 mm on the stroke. I asked Neil if it was possible to run a 21 or 22 mm wrist pin that would provide the same strength as the 23 mm pin. Neil checked available materials and methods and determined we could use a 22 mm pin. Viola ...... another .5 mm.

Put this all together, we can make a rod which is just over 130 mm's long while providing a great rod/piston angle ratio by off setting the piston's wrist pin hole to the side by a certain amount.

Bottom line is we will have basically the same benefits as the 132.0 mm rod length.

As stated above ......... pistons and rods are in production.

 

Today I decided to cancel the production of the rods and pistons. Performance Developments will being shipping all the parts back to S Car Go. I have decided to go no further with this project.

I am sorry to have disappointed those who have been following this build over the last five plus years. I am disappointed myself. I will explain what lead to my decision once I get all my thoughts together.

 

Chad....PM sent

 

Chad, thanks for calling VR and taking care of him, that was very nice of you. It's a small community after all

 

Chad,

I'm sorry to hear you have reached this point, but having been through some lengthy 'experimental' projects in the past ( albeit on a much smaller scale) I can perhaps understand.

You have obviously tried to use some ground-breaking techniques in your quest, but the reality (from my position as a remote outsider) is that it has taken far too long leading you to become a one-man development shop with manufacturer level technology. In addition, the world has moved-on to the extent that the project has continually been refined in terms of technical and performance objectives, with the result that it has never delivered what you wanted i.e. a usable car that gave the performance desired at that point in time.

best regards

Guy

 

Guy,

I will explain what happened and why in about one week.

 

Hey CJV, sorry to see it come to an end I know it's been a long, long road. Keep yer' chin up as they say in the UK

 

alex,

I always have my chin up ........ just sometimes a little higher than others.