Tonight's project- Flappy solenoid reassembled:

Before:



After:

 

Very nice, Rob! That thing is going to be too clean to drive when you're done!

I understand Greg's aversion to the allthread. One technical(non-vintner ) reason not to do it that way is you risk damaging the seals on the bearings with the allthread.

 

Allthread....stacks of washers under a too long bolt or used as spacers...supercharger systems that have water heater parts from Home Depot..sway bars with bent rod ends and cheesey spacers: They all make me feel dizzy and sick to my stomach.

 

Rut Roh.

 

You know Rob, with such a clean engine bay your gonna need to have the car painted. Might as well do that before you drop the new engine in there.

 

Nah, paint's fine. Except for the big wrinkle around the headlight on the right, and the rust bubbles under the right rear quarter window, and the scratches under the door handles, and.....

Yeah, you're right. Better get it painted.

 

Next item on the list is installing the LH and EZK PEM's for easier sharktuning.

John Speake was kind enough to pre-burn these PEM's with the stock 90GT maps for me, so I can install them now (and make sure I didn't FUBAR anything) and can then at least start the car post transplant.

The instructions for the PEM installation are on John's website (http://www.jdsporsche.com/faqs/PEM%2...0Issue%201.pdf)

But I thought I'd add a few idiotproofing notes.

I remembered to disconnect the battery this time.....

First, the LH and EZK in situ- Held in by two 5mm hex bolts, hidden behind the LH brain connector at far right:


The ignition control module is held on with 2 8mm hex screws- undo 1, loosen the other and swing the module out of the way. THis allows access to the last of the four M8 nuts that hold the EZK brain onto the frame. The cover over the LH brain is held on with 6 M8 nuts

Once the brains are out:



The LH brain cover is held by ~10 tabs, fold 'em back and remove the cover. The EPROM has an annoying plastic cover that clips over the sides of the EPROM socket, it can be gently pried along the side to pop it off:



Pull the EPROM and seat the LH PEM. (Note the JDS Porsche 'tile' at the lower right, I got this 'tiled' replacement brain from Louie Ott in 2007 with a '90 GT EPROM (note the part # on the cover is a standard S4 LH brain) since the previous brain was 12 years old and I didn't feel like getting stranded )



Reinstall the cover, gently bend the tabs back down and yer done.

The EZK is a little more complex- The case is held together with 8 T-10 torx head screws:



Undo them and slide the guts out of the case. There are two plastic sheets that cover the IC leads, note their orientation.

To open the board 'sandwich', first you then need to undo 2 philips head screws as John illustrates- mine were pretty tight, I used a very low speed electric drill to loosen without stripping them. Once the screws are out, there are two plastic snap connectors that hold the boards together- they come apart at the arrows:



Undone:


Then the board can be laid out, and another annoying plastic cover can be removed from the EPROM (at top right):




I pried the old EPROM out with a small flatblade screwdriver (don't fulcrum on the edge of the board itself...) and installed the EZK PEM:



There is a resistor that sticks way out from the pin connectors that needs to be bent to the right a little to clearance the PEM board- pretty self evident as yo uclose up the board sandwich. I only had to bend it perhaps 2 mm:



I then buttoned up the EZK, assembled the brains back into their rack, and stuck it back in the car. Total time less than 45 minutes, even with the picture taking. Easy peasy.

 

The actual lift and duration numbers actually tell only a piece of the story, about a camshaft. The "bigger" lift 928 camshafts actually have a fair amount of harmonics. Of course, Porsche did not have the equipment or ability to calculate this, years ago, when these cams were designed. Camshaft design has evolved a great deal, in the past few years. Please note that I'm a far cry from a camshaft designer. I understand what is happening. Since I've had my own flow bench for almost 30 years and port all my heads, personally, I've got a pretty good idea of what I would like to see happen. Knowing how to change it to work better is beyond my abilities.

In simple terms, we worked pretty hard to increase the nose radius on our camshaft design. We wanted to do this for several reasons, but the biggest reason was to take advantage of the increased airflow through our ported heads. This is the obvious reason, but it actually did several other desirable things. This reduces harmonics. This reduces the load on the entire valve train...thus reducing the needed valve spring pressure. As hinted, it also allows the valve to spend more time open, when it is near peak lift.

You have to be a bit realistic when looking at lift numbers. The camshaft spends a nano second, at peak lift. In order to get a "real" picture of what is happening, you really need a "bigger" picture of what is happening right around peak lift. While simply increasing the time the valve spends, near peak lift, allows better airflow through the engine, it also tends to increase the time the valve is open, overall. (Increases duration.) Increasing the duration generally will cause the engine to be "dirtier". (More emissions.)

So, balancing a increase in the nose radius, without creating undesirable duration, becomes a real technical act. Many things come into play here. It was a real interesting exercise, but we think it will result in a much better camshaft design.

Food for thought.

 

Is this a real concern in your motors Greg? (edit, that did not sound right, what I meant was do some your custom motors have to pass a emissions test)
I have heard horror stories about Ca and emission testing (ours is the same test, but no visual except to see if the converter is present)

I know this is apples to oranges, but every 928 cam I have seen and they have all been stock and the custom ones I have seen pictures of, the ramps seem to be less aggressive than the domestic performance V8 counterpart.

The lobes on the 928 cams seem to have a much sharper nose IE not a lot of duration at or near max lift.

I do agree with what you are saying, before the computers could help make cams it was more a art than a science.

And there is a lot more to it than numbers, as you say.

I am in awe of some of the newer technology used for opening and closing valves, variable advance, variable independent lobe separation, variable lift,.

I think Ferrari even built some test engines with out cams using electromagnets to control the opening, closing and amount of lift.

Neat stuff.

 

Greg:

Yes, many of our engines have to pass emissions testing. Even the engines that go to Europe have to pass some sort of inspection. I also like to do the best that I can to help reduce emissions. Cleaner has to be better...for a many reasons.

No doubt that the 928 cams are somewhat mild, but until I get some cam blanks done, I'm stuck with what I've got to work with.

Yes, newer technology is interesting, even just watching what is happening with regular cams and lifters. A few years back, Porsche started using what I call "flat" lobe technology on their race cams for the GT-3 engines. It was almost like they ground the "opening ramp" flat for 20mm, or so. You could feel the flat sides on the lobes. This was more about friction and wasted lobe contact on a large follower, but was interesting to think about.

 

I am all for cleaner engines, I honestly think that our engines would not be what they are today if the auto manufactures had not been forced, kicking and screaming into reducing emissions and increasing mileage.

It is taking it to far that I have a problem with, I can see a future that has huge tax rates for engines over 2 liters, I have a issue with that.

Your job of building reliable horse power is hard enough with out throwing in a emissions requirement.

Your old enough to remember when engines that had 100,000 miles on them were junkyard refuges, now most engines can go a very long way if serviced correctly.

 

FYI my 6.5L motor built and tuned by Greg passed California emissions just last month by a margin of about 100 to 1. It was cleaner than my 2006 Acura TSX 4-banger.

 

That is clean, I would not know where to begin trying to make a hot rod motor that would pass emissions testing.

 

Mine will have to pass smog in May 2010. Sort of begs the question of how much room there is for tuning within the confines of the emissions standards (not that I want to push my luck on the subject....)

 

I think that there's a happy coincidence that all the work done to make the fuel and air flow really nice into the combustion chamber and then burn really thoroughly also tends to give you good emissions results, assuming you put a fresh set of well warmed cats in the exhaust stream

Here's the results of my 6.5L sniff test (with something like 200 miles on the freshly built motor):