[flash]

i've been working on this the better part of the day - just about have the mounting plate all laid out (i'm just fiddling with alternator pulley wrap angle) then i fire up the band saw and start making the mockup plate - a couple of simple brackets and then it really just down to the airbox - i'm figuring to have mockups of most if not all of the parts by the end of the weekend

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[PorscheDude]

Very cool.
I'm really glad this is coming along so quickly and your having
some fun doing it.

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[flash]

i am actually having fun - it's been a while since i did anything quite so involved - it's a lot of 3D thinking - but i'm taking my time and it's paying off - each time i look at it i clean something up and improve a detail - it's getting REALLY close now though - i think tomorrow i'll have all the major parts mounted - then i just need to work out belt length, adjust pulley locations to suit, and it's onto the airbox - once that is done, i make the real prototypes of the mounting hardware and such, and then it's off to testing

my goal is to have a decent mockup shot before xmas, and hopefully have the prototype mounting stuff in that shot - not likely i'll have a prototype airbox or trim pieces by then though

still on target for early january tuning and testing

still on target for output numbers (no changes from original expectations)

still on target for under $4k complete kit pricing

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[PorscheDude]

Awesome...

No christmas dinner for you!!
There's work to be done.

Can't wait till you shut the naysayer's up, and
show'em how it's done.

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[flash]

got stalled waiting for some parts - they arrived today - back on it this afternoon

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[wmuldowney]

Now I really regret having a Tip. So guess its gotta go. Did find a nice BLK/BLK cab 6 speed, going to look at it day after Christmas.

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[Ryan]

Make sure it's not a 92. Did anybody find out when they changed rods in 92? I wonder if the S2 has the same design?

I am still bummed about the whole rod thing.....

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[flash]

per a technical bulletin of jan 1994:

For the 968, "as of October 1, 1993, engine #42R0958 - #42R50621"

casting #944 103 111 2R (17.0mm thickness) vs. the original casting #944 103 111 1R (10.0mm thickness)

they were reinforced at the connecting rod bolting surface

i have not yet been able to figure out which car serial number is the last engine serial number in that group

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[Cloud9...68]

Thanks, Flash, for looking into this, on top of all the work you're doing to develop the supercharger kit. Does anybody know where the engine serial number is located?

I'm not sure what the "as of October 1, 1993" means, but it sounds a little ominous, as though the thinner rods may have been around a long time, maybe even into the 1993 models. I hope my interpretation is dead wrong, though [img]style_emoticons/<#EMO_DIR#>/ohmy.gif[/img] .

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[flash]

lol - i wondered the same thing - that's why i need to match the engine number to a car serial number

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[flash]

made SERIOUS progress today - i almost finished all the "hard" stuff - i ran out of daylight or i would have gotten a lot farther

got the mounting plate mock-up done

got the mounting brackets designed - will have mock-ups done tomorrow

got the tensioner worked out - will complete on monday

got the belt length worked out - will order belt on monday

i expect to have the entire drive plate hardware mock-up assembly mounted tomorrow and all components on it on monday

then it's the airbox

everything else after that will go quickly - it's just plumbing really - pretty easy stuff

then everything goes out for fabrication - it will take a week or two to get everything made - then i bolt it all together and it's into the trailer and off to the dyno

sorry i missed the xmas photo goal, but i'll definitely have some form of pics before the 1st

still looking at mid january tuning and testing

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[PhilG968]

Good work.

Really sad about my 1992, I was really excited about this upgrade for my car.

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[flash]

well, one way to look at is that if you need a valve job (like if you have 100k on the engine), which you would have to do anyway before doing the supercharger, yanking the pistons and swapping out rods becomes pretty easy - then you're good to go

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[PhilG968]

Excellent news, back in the game. Was putting a new head on anyway.

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[flash]

yup - the rods swap out, so not really horrible news - call pete at rs barn

when you're done, you'll have a bullet proof monster

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[Cloud9...68]

I don't want to get too far afield with this, as a new thread is warranted to get into the nitty-gritty details, but is yanking the pistons and slapping on a new set of rods on these engines really as easy as it sounds? Doesn't pulling the pistons open a whole new set of requirements, like honing the cylinders, determining if oversized rings are needed (depending on how much material needs to be removed), testing the ring grooves for wear, and replacing the pistons if the grooves are out of spec, balancing everything, testing the block for trueness in every dimension, etc.? Focusing just on the cylinder honing for a second, isn't this something that's way outside the realm of the average do-it-yourselfer, given the exotic construction of the 968's block? Not to mention removing the pan to unbolt the rod bolts, which is quite an undertaking in itself (though not a task requiring any specialized skill).

I guess what I'm getting at is, if you're unfortunate enough to have an early set of rods, does adding a supercharger entail a detailed rebuild by a shop specializing in these engines, which could easily add many thousands of dollars to the cost of the conversion? This compared to simply pulling the head and taking it to someone to rebuild, which, while not exactly trivial, has been covered in very good detail recently? I don't want to panic anybody, but I want to make sure the scope of this task is comprehended. Are the early rods <i>really</i> that much of a risk? Please tell me I'm blowing this out of proportion [img]style_emoticons/<#EMO_DIR#>/huh.gif[/img] , as I would love to add a supercharger to my engine.

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[firefish]

Since the rod bearings are a known weakness some replace them as a preventive measure. Why couldn't you do the same with the rods? Sure, there's always a bunch of stuff that you could look into since you're already "in there" but you have to stop at some point. I'm terrible at this myself as I always do too much (read: spend too much money). But where's the limit?

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[flash]

honing a cylinder is a very simple procedure, and any half-way decent shade-tree mechanic can do it easily - boring is a different story

fitting rings is also easy

as for changing the rods, i've not done it on this engine, but it's always been a very straight forward procedure in any engine i have done it on - choosing the right size bearings has been the only issue - the tech bulletin from porsche also indicates that it is not that big of a deal

we'll get into all of this though with a complete "what to do if..." posting when we are done

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[Cloud9...68]

OK, sounds good. I'll wait for the "what-to-do-if" post. The good news is that by going through whatever precautions deemed necessary for a safe SC installation, one will end up with a very solid, reliable, durable end result for a fraction of the cost of a new car giving comparable performance.

But you hit it on the head with the honing vs. boring comment. I've honed several blocks, and you're right, it is a very simple procedure. My concern is how to determine if boring is necessary, without taking the whole thing to a mechanic. In other words, how can one keep the supercharger install within the realm of a DIY project, and not worrying that you've made an error in judgement that could cost you big time down the road? But it sounds like you've got all this pretty well thought out. I'm sure whatever recommendations you come up with will be beyond reproach.

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[flash]

no worries - the tolerances and specs are known - all that would be required is a good measurement and a good eye for flaws

the bores on these things are pretty tough - i'm not envisioning a lot of problems here

but you can be sure that pete and i will put together a really good sheet on what to do to make the decisions and how to take the steps needed - we don't want anybody bolting this thing up and blowing up their engine - in fact, we are going way overboard with making sure we inform and caution people so as to prevent that

but, it's the right thing to do

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