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-   -   Thoughts on 911/20 ST Type Engine (http://forums.pelicanparts.com/911-engine-rebuilding-forum/387301-thoughts-911-20-st-type-engine.html)

cameron.arnott 10-05-2009 09:40 PM

Hi Mark

Keeping the SSI's just in case i need some heat - might do Targa Tassie one day....even Classic Adelaide had some wet weather last year and the demister was needed.

George Cairns in Melbourne makes the muffler hence the name. I know at least once guy running in Sb Historics using one on his '67S with good results and also a heap of tarmac rally guys - both MFI & carbs Obrut (Ryan is one) I'd guess at it being about 1/3 lighter than my triple outlet rally muffler I had on before. When I switched to the Cairns muffler I lost none of my top end and it literally flattened out the 'on cam' feeling of the S cams from about 5k up. Lots more mid range which it sounds like you could do with!

Planning to run a single MSD - twin plug system with 2 MSD coils.

In terms of the cams I guess time will tell but I know Kenik and Camgrinder worked on the combination of a good top end combined with bottom end pull. I believe the key is the 102 degree lobe centres matched with the heads.

Planning to stick to about 8k but I guess time will tell on that one :D

cameron.arnott 03-03-2010 11:01 PM

Engine is done! Final specs are as follows:


• 2.4 7R 911/91 case, shuffle pinned, oil bypass mod, 996 turbo pump, case savers, resurface & line bore
• 66mm ‘S’ counterweighted crank , cross drilled, balanced magnafluxed + micro polished
• Pauter rods
• 10.5:1 JE pistons – mechanics special recipe
• Nickies 85.5mm barrels (sized to racing regs here)
• DC 44 Cams on 102 degree lobes
• JB Racing Twin plug distributor
• Supertec head studs
• Heads ported, racing valve springs & titanium retainers ( Steve Weiner)
• Webers with tall secondary venturis, port matched tall PMO manifolds
• Aussie made ‘Cairns’ muffler
• Single MSD

This things rocks! Public thanks to Kenik who's engine specs I basically copied other than induction and minor odds and ends.

A very fun day at the track today :D

kenikh 03-03-2010 11:11 PM

Sweet!

Flieger 03-04-2010 12:10 AM

This thread is worthless without photos (or better yet, video with stereo sound). ;)

Steve@Rennsport 03-04-2010 12:11 AM

Good news, indeed,....:) :)

billybek 03-04-2010 04:29 AM

Quote:

Originally Posted by Flieger (Post 5216919)
This thread is worthless without photos (or better yet, video with stero sound). ;)

+1!!
I have been following this thread for two years and this is all we get!
Come on! ;)
Sounds like a cool motor. Post some pictures and or video soon!

cameron.arnott 03-04-2010 09:06 PM

Nothing like an audience :D

I'll post some stuff when I get home to my own computer.

Thanks also to Herr Weiner, for the magnifcent head work !

Ballpark numbers are around 220 HP at the flywheel....

Steve@Rennsport 03-05-2010 03:04 PM

Quote:

Originally Posted by cameron.arnott (Post 5218705)
Thanks also to Herr Weiner, for the magnifcent head work !

Ballpark numbers are around 220 HP at the flywheel....

Hey Cam,

You are most welcome,......:)

Those things do move some air right along.

E-mail me your dyno sheet when you get a chance.

kenikh 03-05-2010 04:23 PM

It is a beautiful thing when a plan materializes as planned. That is just awesome.

cameron.arnott 03-05-2010 07:08 PM

I'm going to get the car back to the mechanic next week. The emulsion tubes (F3's) need a bit of sorting, mixtures are good but transitioning up from 2500-4000 at part throttle is a not quite smooth. Will try to get it back on the dyno as its only been run to 7300 on its set up run. Maybe F 26's might be worth a try?

Fairly conservative advance at the moment as well.

Running 34 venturis still, not sure if 36's might kill the low rev driveability a little.....

The track day might have helped things loosen up a little as well so another run up to 8K might be interesting!

Will do Steve ;)

Highfield 03-06-2010 03:51 AM

Cam - great to see the time taken and investment in research (and no doubt the saving up) has paid off.

Looking forward to pictures, video and dyno sheet :-)

Ian

cameron.arnott 03-07-2010 06:59 PM

Thanks Ian

The car is going back to the mechanics this week for a little bit of a fiddle.

Hopefully I'll have a new dyno sheet at the end of the week. I've just flown back home and relaised I didn't take a copy of the first run sheet :( Bugger!

Cheers

cameron.arnott 03-08-2010 03:24 AM

Evidence!

YouTube - Twin Plug Porsche Engine.MOV [img]

http://forums.pelicanparts.com/uploa...1268050815.jpg

http://forums.pelicanparts.com/uploa...1268050903.jpg

http://forums.pelicanparts.com/uploa...1268050950.jpg

http://forums.pelicanparts.com/uploa...1268051035.jpg

cameron.arnott 03-09-2010 03:02 AM

Some track footage...

YouTube - Mallalla Track Session 2 (3 laps).wmv

billybek 03-09-2010 04:33 AM

Sounds great!
It is nice to see some leaves on the trees too!

Flieger 03-09-2010 03:38 PM

Bonza! :)

cameron.arnott 03-09-2010 03:39 PM

Trees? What trees..?

Edit: oh those trees! Couldn't remember seeing any ;)

tadd 04-21-2010 12:54 PM

Is there a dyno sheet on this puppie yet? Enquiring minds!

t

cameron.arnott 04-21-2010 03:15 PM

Hi Tadd

Here's the original Dyno run from the engine break in runs.

As per the other post this run was only to 7300rpm when the limiter kicked in (it was still set to the old engine spec on the MSD2 and they had thought at the time it needed a different plug in vs turning the adjuster screw!)

They had a bit of a fiddle after the 1st track day with emulsion tubes etc but had a batch of race cars to prepare and ran out of time before the car carrier collected it to bring it north to where I live. Hence no second dyno run :( I would like to spend some more time getting it perfect but there is not a heap of talented Porsche mechanics where I live.......

There are still some surging issues on the idle circuit, particularly when cold but it pulls like a steam train, and has loosened up a little from the beginning.

I'm guessing 220-225 at the crank at peak HP. Rev limiter is set at 8000.

Cheers

cameron.arnott 04-21-2010 03:25 PM

Sorry now attached.....

http://forums.pelicanparts.com/uploa...1271892309.jpg


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