freedman

Voice of reason as alway Alex, I think thats where I'd be headed.

Colins posts are also really hepful (makes me pleased I've got a couple of 9M invoices in my cars history)

NineMeister

Final thought for the night before this discussion gets too serious:

Is mapping an engine using knock control the equivalent to tuning a grand piano over the telephone??

Porsche964FP

Great metaphor Colin, touché.

Steve Weiner-Rennsport Systems

Colin,

The state of pump gas is quite different in the US, compared to the rest of the world and I can make a good argument for effective knock-sensing on cars that do not use race gas.

Our street fuels range from 91 (R+M/2) to 93 (R+M/2) and contain 10% ethanol in most locations as mandated by the federal government. Further, the lack of quality assurance and compliance by each state has created a distinct lack of consistency about whats delivered at the pump.

Naturally, cars using race fuels do not need any kind of knock-sensing as you know,...

Given the potential consequences in street-driven cars using pump gas, effective knock-sensing offers a level of insurance and protection that's simply prudent to employ.

race911

Unless you're at Laguna, and buying gas from their pumps. More than one episode of mass detonation damage....... (At this point I only buy either 55 gal drums of Sunoco from one of my answering service customers that is a petroleum distributor, or smallish drums locally from ERC.) My personal experience was a POC weekend circa 20 years ago where at least four 944 Turbos puked head gaskets. Thankfully we were able to borrow a trailer and get my friend's car up to my place so I could repair it, and he hitched a ride back home to San Diego.

And yes I've busted up rings/lands on Euro 3.0 and 3.2s in my own cars way back when, mistakenly only running 91 pump gas when temperatures were above conservative levels.

So, just as the roads suck here, the gas does too.........

And as always, thanks for all the time everyone puts into these threads. While I'm set for the moment with my engines, it's great to have read/re-read these topics so I can vaguely recall what's what when I'll have occasion to build or recommend something.

warmfuzzies

I started my conversation not wanting to name Christer as the whole issue was not the information I sought, but yes it was Christer, and I was one of the people who met regularly with him At Raymonds, and who he left at Le Mans before travelling to Denmark before his car decided to fail.

Enough said.

My question was borne not out of malice, but genuine information as to how far the technology has come. If despite and in all the best will, the tanker driver fills the wrong reservoir up, you could have a buggered engine through no fault of your own, I wanted to know if the technology that releases so many BHP had advanced far enough to be able to prevent knock causing an engine failure, it seems it very well might have, so thank you for the answer.

Regards

kevin

boxsey911

Steve, a little off-topic but are you seeing any fuel line problems because of the 10%. Porsche themselves stated that 10% ethanol cannot be used in our cars. Here's their official word on the subject:

http://www.porsche.com/uk/accessorie...-05-23-classic

Steve Weiner-Rennsport Systems

Yessir, we have. Ethanol, despite having an RON of 114, attacks any elastomer in the fuel system such as any rubber lines, O-rings, seals, etc. Even Viton seals do not last forever from contact with that stuff.

Race cars using leaded fuels do not contain ethanol so those vehicles do not display any symptoms, aside from the regular replacement of the fuel cell foam and liners. Unleaded race gas contains a preservative and we usually add a bit more of that to help prevent corrosion and degradation of fuel system components.

Street cars using unleaded fuels containing ethanol need an additional dose of the same preservative product (Stabil) that really seems to help extend the life of these components. For that reason, I tell my clientele to use that product on a continuing basis for durability.

NineMeister

I appreciate that Kevin and I fully understand that your question was asked without malice; unfortunately it is hard to be truly objective about the subject of knock control after the umpteenth time of having the same discussion and dealing with all the negative bulls**t rhat usually surfaces.

That said, you are absolutely correct that technology moves on there are better ways to feedback control the ignition timing of an aircooled Porsche engine than listening to a microphone which only tells you when it audibly goes wrong. Let's think about that for a moment: if a knock system uses a microphine that picks up audible knock which then tells the ecu to retard the timing, once knock is present the ecu must react by shifting the ignition in a large retard step to stop the knock from continuing. The ecu tsubsequently re-introduces timing unless the engine knocks again.

With the help of an assiciate we are working on the design & development of a new ecu for the aircooled and watercooled GT3 flat-6 engines which employs a radically new control strategy that can instantaneously detect ignition timing errors long before the onset of knock. I cannot divulge any specifics but I can tell you that we are proposing to use the new system for the first time on the 3.82 litre race engine destined for the Gulf Blue 9m11RS that is in construction. Watch this space.

JasonAndreas

Slightly anecdotal but MTBE was banned and E10 introduced here (in New England) almost 10 years ago and I don't remember hearing any 964 or 993 owners having any related problems since.

Porsche964FP

Good morning,

So having thought more about the way in which I want to use the car and the future coming years here is the setup I'm leaning toward - I'm searching for advice on specific components to use.

ITB
PMO or Jenvey, I like what I've been reading about the Jenvey and they're very well priced in comparison to others.

http://www.jenvey.co.uk/home/throttl...ody-kit-ckpeo1

http://www.jenvey.co.uk/home/throttl...ody-kit-ckpeo3


CAMS
For ITBs it seems RSR cams are the choice. What other choices are there?

P&C
Mahle & Mahle - Apparently for durability this is the definitive set up. I read that there are two versions - what are they? I understand that one set is thicker and therefore better for durability.

JE & LN Nickies - What are experiences with this setup? I read JEs are lighter and therefore perform better. In fact I held one recently - very light!

Omega pistons - Any feedback here? I hear these are the dogs/ overkill - but also very expensive. What cylinders would these be coupled with?

Mixing JEs & Mahle seems to be a bad idea - different expansion rates, piston slap...

CON RODS
I've been reading about Corillos but it seems Pauter perform better and are cheaper by a substancial chunk.

VALVES
Schrick valves (993 spec) for better performance. Stiffer valve spring and titanium retainers.

CYLINDER HEADS
Porting, polishing. Changing valve guides - could someone expand here? Seats need modifying.

INJECTORS
Siemens Deka or .....?

ARP
Head studs & rod bolts.

ECU
Motec is so expensive - MBE looks very attractive.


Oh and a big thank you to rennlister 'SB' for all the engine chat

Cheeksyboy

I can only comment to some of the above....

I've got Jenvey on my Westy...very nice kit in that application.

Injectors I would have thought will be determined by the amount of flow you need to achieve once you've selected your cam and RPM range so that option of makes will limit itself to some extent.

ARP studs and bolts, again I've got these in the Westy and considering I built that engine it's still going strong after 6 years and many trackdays in different conditions (sand and heat of Bahrain to rain and cold of Mondello)....

and Motec, as you know I've got this in the Hornet....and I agree it's expensive.....your selection will also come down to which engine builder you use and their experience with difference systems.....why not call Wayne at Chipwizards for an impartial comment (not used hi myself, but he seems to be able to map almost anything according to some listers on 911UK)?

KiwiSean

Disclaimer- I've not done the ECU on my P car yet but on previous performance vehicles, if you're not going Motec (which is the best IMHO) then look at Link or Autronic.

+1 on Cheeksyboy comment on your builder + tuner recommending an ECU. I would let whoever builds it decide on the ECU. I'm not saying I'm right or met everyone on the planet but most guys I've met prefer to use a certain ECU and can get better results through familiarity and confidence.

This is the challenge I have in NZ, I want Motec but can't find someone that's tuned a Porsche on it yet and don't want to take the risk. When you drop this kind of money on a rebuild, a blown motor is the last thing you want.

It all gets back to the discussion around packages I guess, now with the human element involved just to complicate things.

NineMeister

synergy [sin-er-jee]
noun, plural synergies.
The interaction of elements that when combined produce a total effect that is greater than the sum of the individual elements, contributions, etc.

ras62

Or perhaps dysergy, the opposite of the above by the sounds of things!