Bigfoot928

Here is a question... Porsche spent millions to develop the variocam, and the associated parts... the 968 was 3.0 liter and the motor I built was 6.4 liter, so we tried to stay lean on the side of engineering. I would love to see the $millions spent on engineering saying the ports are too big for variocam. Number of people working for Porsche designing variocam? Raise your hands? Number of people who have built and run variocam on a 928? Raise your hands? ok... we have a consensus here. Theory is nice... but if that is all you have then...um yeah... let me know how that works out for you.. and your 928 that shows up at multiple events with it working....

BC

Lizard928

I have a question.

On your original design, you used 2 of the stock 968 tensioners.
You had a pad fail due to load which came off and jammed the camshafts.

On a stock 32V system, one of the tensioners is inverted due to the camshaft chain load.

Has this been addressed/fixed to prevent the problem from reoccurring?
Have the valves which were bent replaced, and reground?

I've considered grabbing this off you for awhile. But these couple of things have left me hesitant.

Bigfoot928

No valves were bent, Neither of the tensioners are inverted, which was a rumor started by someone on here years ago, A good cleaning, new tensioner pads, and I would recommend new chains should have this up and going. I think it would make a really strong otherwise stock engine.

Vilhuer

Question is should they be. Is 968 tensioner equally capable to push on both directions or is one direction stronger than another? If they are same, direction tensioner is mounted don't make a difference. If not, it makes sense to invert drivers side.

Bigfoot928

Both sides work the same, no difference in direction.

SeanR

Having ridden in the car, looked at the engineering, it's pretty damned impressive.

Bigfoot928

These are some very very very simple principles, on a white board with 5 circles and 7 arrows it can be easily explained. However. Keep in mind I spent over $10K developing this, making it work and explaining it to several hundred people.... guess how many understood it? less than 20. The people that understood it had no questions.... the hundreds that didn't peppered me with questions until I gave up. Sorry folks not doing that for free again. This is a for sale thread. I can dismantle and sell the tensioners for half the asking price. 968 intake valves about the other half, and the rest I can have melted down into oblivion and end up getting more than I'm asking. Mistakenly I assumed someone on here would want to take this stuff and move it forward. I guess not. Saturday its all getting dismantled and on Monday sold as scrap. pearls before swine.... I should have just done that in the 1st place.... but then I would have been crucified for destroying it. After its gone and someone wants to do it again... my response will be good luck and may ye have a fat wallet.
I won't be weighing in on this thread again except to say its sold or melted down.

I wonder how my thread for ebeich springs will go? they will be up for sale as well. hopefully there is a shorter learning curve on that one.... otherwise? those 2 will get melted down along with all the other NLA hardware and bits for 928.... and at some time you have to decide what is better for me vs the community....

17prospective buyer

This is a hell of a deal, someone buy this just to have it...

GregBBRD

Sad to see this level of genius development reduced to scrap.

And sad to see you guys tearing this level of an "experiment" down.

Not everything, the very first time out is perfect. I'm guessing that no one here has the funding to spend the huge amount of dollars required to engineer and then perfect a development project this large. Almost all of us are working on a limited budget and have to make some assumptions when we make something.

I don't give a crap how big the ports were. I don't give a crap what the cam timing was. I don't give a crap how well this worked. It's 928 "developmental art"!

I'd be all over this, even at twice his asking price, if I wasn't so "deep" into developmental projects of my own (there's only so much "loose" money around for me to spend on things that loose me money, because of the tiny market and I'm too extended into too many projects, right now.)

But I'd love to be able to look at this wonderful engineering, screw it on the top of a stock engine, and see how it works!!!! Even if it isn't absolutely perfect and needs some developmental changes (which is certain might need....it was the one and only prototype) it is one hell of an interesting "starting point"....and an incredible bargain.

Most of us are doing this stuff for the "love" of the breed and to help keep these vehicles around. Very few are profiting from this. Some are doing this stuff the make these cars "more current" with the newer vehicles. This is a huge amount of effort and a huge investment in dollars.

I know, for a fact, that I'd be millions of dollars ahead, if I never developed a single thing for the 928 market and simply spent my time doing oil changes, services, and brake jobs on new Porsches.

Are you guys really thinking about what you are doing? Jumping all over some guy's self funded (never going to get a return, wasn't ever part of the plan) really elegant experiment with both feet doesn't encourage anyone to develop anything.

Are you guys seriously trying to keep people from thinking and developing pieces? Is that really long term beneficial to you?

Look if someone makes and markets a piece of crap...for profit...rip the hell out of it. ("High volume" fuel rails that have 1/2 the volume of the stock rails comes to mind. Generic "chips", sold for profit, which are "firecracker lean" comes to mind.)

But tread lightly on people's efforts to develop a "better mousetrap".

You guys should be ashamed of yourselves. Nothing negative said here does anything positive for this community!

fraggle

+1

Ketchmi

I have to agree with Greg, if not used and further developed these parts should be put in a museum for future 928ers with an open mind to gain ideas from. I seriously considered purchasing them myself to see how they responded to boost but I am in a situation of reducing my projects.

Yes, Sterling can be a bit dramatic but I know how he feels when his hard work/designs are torn apart by people without the practical knowledge of application and never will attain that level of involvement in a one-off project. You don't think his port size or valve size is proper? Do it differently on your variocam project. Oh, wait...nobody else is doing a variocam 928 setup? Anybody?

ptuomov

Not everyone here knows all the "inside baseball" stuff that happened a decade ago. I didn't start paying attention before 2009, for example. I'd be interested in seeing more photos of the system. I'd be interested in seeing a dyno graph. I'd be interested in hearing how various technical challenges were solved, such as how the 968 tensioner was adapted to the driver side. I don't think asking for these kinds of things in a for-sale thread is out of bounds by the community standards. If someone interprets this as me pissing on someone else's work, they are misinterpreting me.

hacker-pschorr

I saw one person seriously questioning the technology and claims by these products.

Then two more jumped in for comic relief.

All the other comments I see as legitimate questions by interested or just curious people. Which can be expected from such a radical modification to a 928.

That being said, those posts are gone and those users sent a PM.

Remember guys, this is a for sale thread, show some respect please.

Bigfoot928

for getting cranky. yeah I'm passionate about 928's. yeah I'm touchy about the variocam subject... for well over a decade it has been a topic of discussion. I've been called a fraud by people that didn't see or hear it run... yeah other dfw 928 owners have come to my defense over the topic when I wasn't present.... so I will try to answer some of the questions.

Here is variocam on my 928 101

http://www.928sg.com/heads.htm

many have asked if the pad failure was such a simple fix why didn't I just replace the pad and go back together? The simple reason is the variocam was designed to make a small engine feel like a big engine by increasing torque. It works well. Too well for a stroker 928 engine. It was a blast to drive. Tires never lasted long.... 400 ft lb torque right off idle is fun... but I wanted more high end HP.

If I was to put these on a 928 engine to move to the next level, I would put a bigger intake cam on it... More than likely a 2mm base circle grind with 2mm valve buttons would be fun on a 5 liter. The stock pistons on a 5 liter would have to be fly cut for the larger intake valves.

I lost the dyno info in a decade of computer changes and the dyno itself changed hands.

Here is the million dollar question..... Would I do it over again? yep. was it cost effective hp and torque? nope. not even close. how much fun was it to drive? a blast. how fast? I don't know. how fast did I pull away from an entire pack of 928s under full throttle on the way to sharks in the mountains? I pulled around them like cones at an autocross. $800 in fuel to get to NC from texas and back was stupid money.... but that was what it burned.....

The biggest problem with selling something like this is that no matter who buys it, they won't be as passionate about it as I was... they won't spend hundreds of hours on just cam timing to get it dialed in like I did...

I don't know how it would work with boost..... I do know that based on the dyno info that I did have, and the cam timing that the intake cams needed to be bigger.

I should probably just keep it all and buy a scrap beater 928 and build it up.... but I haven't even finished the one 928 that I have... some of you guys have 3, 4, 5 or more 928's... lol now that would be torture for me.... all the things I'd want to try next...

I will see if I can dig up more info just for the archives and more pics.... most of this started when pics were printed from film....

my thoughts on the tensioner pad failure..... Early tuning resulted in a broken cam gear on the side that the pad failure resulted in years later. That original cam failure and the early dyno tuning that had tons of detonation probably resulted in the pad failure... the detonation wasn't bad enough to cause piston damage or rod bearing damage but can be pretty hard on plastic parts. hind sight I should have replaced the pads when the cam failed...