What to do when CIS works perfectly?
 

I've had two CIS '83 SC motors...one a 930-16 with 230k miles that ran perfectly and now a 930-10 that runs perfectly...and I mean perfectly as I can monitor my AFR continuously.

I'd like a fI throttle body set up tho to clean up the bay and for the response.....

It is damned hard to mess with something that works....

Like a Dear Abby huh.

uh... play the lottery??!!! LOL

Wish mine worked that well...


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What to do when CIS works perfectly?
 

Is this what you had in mind?
https://uploads.tapatalk-cdn.com/201...37038d8fc4.jpg

It's real expensive but FUN, and it gives a "spicy" engine [emoji4]


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Wish mine worked that well...


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Yes, that's what I have in mind along with a 964 cam.....yup

With that setup, don't waste your time and money on 964 cams!!! ITBs open up your possibilities to REAL cams.


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In 5 years now I've never had a CIS issue.....the present system is excellent....euro SC cruises about 13.7-14 AFR but when I stomp on it immediately drops into the mid/lower 11's...starts on the first crank hot or cold.

I know ITB's will work more efficiently for performance and really cleans up the bay....it is just damn hard to mess with a nicely working unit.

I spend most of my time in the 3-6k rpm range and a 964 works well there...but am open to suggestion.
930-10 w/SSI's dansk pea shooter...

That's a very tidy engine compartment. Just sayin.

What to do when CIS works perfectly?
 

From what I have heard the 993 Sport cam is the hottest one one can use with the original pistons. Any hotter one must go for an RSR type piston.
I have currently a 120/104 WEBCAM cam with 5.2mm lift at overlap at TDC in my 3.2 Short Stroke SC engine and had to use the Mahle Racing RSR pistons.



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Thanks :)


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I would fall over dead!

I run 993SS in my SC and 930. In the 930, they are a weapon of mass destruction. In the SC, they're "fun". I forgot about the pistons...yeah, you're stuck.


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My dear Kenik, lest us not forget you also have large ports whilst many of us must suffer in silence with the lessor. Not that we need to flaunt our more modest size.

Got a test ride in your auto and it was very inspired.

Ricko Swavee, 993SS in the SC are on small ports. I sold the big port heads. :)


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9.8:1 CR Mahles don't hurt either. They clear the 993SS ok, but went with Ti retainers as insurance.


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A wise move good sir, and dang nice performance from SPHs

The '83 930-10 has the large ports with that compression...

Missed it was a Euro, so yes, good compression. Win! IIRC, large port was 78-79 only. Did Euros keep large ports?


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Fie on you good Kenik. ;)

For reasons unbeknownst yea I be in olde English mode, however since I most temporarily reside in Boston, where the British oppressors had their @$$e$ handed to them....

Yes, in the 82-83 models.

Two options for ya:

240 BHP on CIS (hi comp pistons and cams)

http://forums.pelicanparts.com/porsche-911-technical-forum/972927-replacement-cdi-unit-6.html#post9784287

232 BHP on PMOs (no internal mods to engine required)

https://www.impactbumpers.com/forum/index.php?/topic/30521-30-sc-with-pmo-carbs-and-cdi-dyno-plot/

The CIS route will be more 'streetable' but the PMOs more shouty!

What to do when CIS works perfectly?
 

PMO is also very streeable. My twin spark 3.2 short stroke puts out 283bhp and 345Nm with hot cams. It has a very flatt torque curve with 245Nm at the wheels at 2500rpm. and 293Nm at the wheels at 5180rpm.
Costs a lot to build, but WHAT AN ENGINE, real hot in a 1200kg targa [emoji4]


Tahttps://uploads.tapatalk-cdn.com/201...ed156418cc.jpg

You could also use the 993SS camprofile. Gives even more grunt. Or you could "play" with advancing/retarding the 964 cam. One way gives more torque, the other more power.
Think the 993SS is the hottest one when using original pistons.


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Interesting options there....

I doubt I'd go back to carbs....FI throttle bodies would be more like it.

993SS and GT2 cams are the only common plenum cams I like. 993SS is actually pretty great.


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^^ No doubt , PMO twin plug SS motors and FI throttle bodies make a powerful motor.

My impression was the OP was looking for a slightly 'easier' upgrade path. Might be wrong though.

No, you are correct...the rebuilt 930-10 I have is excellent and redone by a master builder...I use about 8-10oz of oil between 3k changes. With the SSI's/Dansk and the lightening I've done (2450 lbs with 20 gallons of fuel) it moves nicely.
What, estimate as set up 220hp as a guess.
What compression were you referring to Johhny as I've the 9.8-1 Euro now?

What to do when CIS works perfectly?
 

Of course Jonny [emoji4] my bad [emoji20]

Then I can sum up the spec on my previous build:

3.0 SC Euro with 9.8:1 cr and 39mm intake ports.
964 cam, lift 1.35 at TDC
46mm PMO ITB
Singelplug
Electromotive Full sequential ECU
SSI

This setup was dynoed to 253bhp and 290Nm. on a Dynapack.

[emoji4]


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Hey, appreciated your input...no 'bad' about it.

That run down looks pretty damn nice.....

Just arm chair talking. On my 81, Engine Builder's Supply cut 0.006" off the heads to facilitate a fresh face for the new seals.

I did the volume calcs and it added 0.2 compression to my 9.3:1. Maybe you have 10:1?

No idea...I run 91 (only thing in Az) + an additive for higher octane and have never had an issue...but the engine does pull strongly from 3200...I'll call Howard up and ask about that...he did the work.

Just a data point. I don't know if 9.8 vs 10.0 means anything. Frankly, I kinda wish they would have shaved 0.012" off if there was no downside, save premium gas.

Guessing Howard knows a touch more than me. :D

10 or close to it is the limit I'd say for 91....altho I do boost it as best I can....I had a 930-16 US 83 and you can def feel the dif in real terms.