3.0 Advice

[Greedymonk]

Hello, I am a newb here just found this forum and have been on it everyday since!

I just bought a 78 911 SC. My plan is to occasionally autocross and see how it goes and maybe move into time trials. I have been asking around about what would be some good mods to bump up the horse power on this motor. So far everyone has told me this is a great reliable motor but after that the opinions are all over the map. I looked into PMO throttle bodies, someone mentioned a 3.2 throttle body and manifold.... I have read about a 3.2 conversion but that looks like a little too much at this point.

I am very new to these motors, is there anything that is the common "no brainer" upgrade to start with? Air filter? Exhaust?

Any thoughts or suggestions would be greatly appreciated

thanks

[Steve@Rennsport]

Hi,

While the 3.0SC engines were quite possibly, THE most durable engines that Porsche ever made, they are not easy to get additional power from without major expenditures on different intake systems, pistons, and camshafts. You simply need a realistic budget along with a clear goal about what you want to achieve.

That said, the biggest bang for the buck on an otherwise stock SC engine is the addition of a pair of SSI heat exhangers and a good sport muffler. Its a 20HP bump and you can sure feel that,....

The stock airfilter unit passes more air than the engine can use so save your money for the above.

[Greedymonk]

Thanks Steve,

What are your thoughts on headers vs. SSI heat exchangers?

[Steve@Rennsport]

Originally Posted by Greedymonk

Thanks Steve,

What are your thoughts on headers vs. SSI heat exchangers?

You are quite welcome,...

There is no practical difference between 1.5" headers and SSI's on a stock 3.0SC. SSI's are simply SS headers with SS shrouds around them for heat. One would need to make a whole host of internal changes before SSI's become a liability,...

[Greedymonk]

Well then SSI's and a sport muffler is where I will start. I hate to sound so newbie but, is there a big difference, performance wise, between single and dual outlet muffler? The duals always looked cool to me!

Much of what I've researched so far tells me that the 3.0 CIS is a great engine but isn't the best fuel/air delivery system. And that the Carrera 3.2 Motronic is more efficient. Does changing out the CIS manifold/throttle body to a 3.2 manifold/throttle body and adding an engine management system sound like a good idea, or a bit overkill?

thanks again!

[Steve@Rennsport]

Originally Posted by Greedymonk

Well then SSI's and a sport muffler is where I will start. I hate to sound so newbie but, is there a big difference, performance wise, between single and dual outlet muffler? The duals always looked cool to me!

Much of what I've researched so far tells me that the 3.0 CIS is a great engine but isn't the best fuel/air delivery system. And that the Carrera 3.2 Motronic is more efficient. Does changing out the CIS manifold/throttle body to a 3.2 manifold/throttle body and adding an engine management system sound like a good idea, or a bit overkill?

thanks again!

The biggest differences between single & dual-outlet mufflers is noise,... Highly modified and large-displacement engines see some performance benefits with some dual-outlet versions.

Without a doubt, the Motronic intake system and engine management is a big upgrade for an SC, but its NOT cheap to do and especially with the '80-'83 small-port 3.0 engines. It really comes down to what your budget is and what your performance objectives are.

[Greedymonk]

okay I just found the thread on the CIS to EFI conversion...

people are using terms like"10K" and "a bunch of Black Magic"...how depressing

For now I will look for other options to compliment the SSI and muffler combo, then when I find those winning lottery numbers I will start to look at EFI conversions..

[Aurel]

Originally Posted by Greedymonk

okay I just found the thread on the CIS to EFI conversion...

people are using terms like"10K" and "a bunch of Black Magic"...how depressing

For now I will look for other options to compliment the SSI and muffler combo, then when I find those winning lottery numbers I will start to look at EFI conversions..

10k seems very high for an EFI conversion. Have you looked at the Bitzracing kit?

[OldTee]

78/79 are pretty good cars just the way they are. Have you considered leaving it alone, tune it to perfection and go. SSI's are good, remove the air pump, put in pressure fed chain tensioners and drive the devil out of it. If it burns an embarrassing amount of oil, do a top. Spend your money on good tires, fix the shifter bushings. Enjoy.

[euro911sc]

Before going too far do the exhaust. Go with a dual out muffler too. They look good and sound good. Drive it that way. The bump is noticeable. Then work the susp. to the max. I suspect you will be satisfied. If not, toss the 3.0 and throw in a 3.6. If you still can't get enough, go get a turbo!

Listen to Steve. He knows EXACTLY what he is talking about

-michael

[fredmeister]

Steve is giving great advice on SSI heat exchangers....they are the best in the bizniz.
I went to them and installed a bursch style muffler exhaust with a flowmaster muffler on my 79 911SC when the banana muffler broke. IT sounded awesome and made lots of power. It was cheap because the Bursch collector is cheap and the flowmaster can be picked up at any performance shop.
Once you have the exhaust not much else to do to the SC engine except start changing to 964 cams and bumping compression....this means an engine teardown.

[sjf911]

Originally Posted by fredmeister

Once you have the exhaust not much else to do to the SC engine except start changing to 964 cams and bumping compression....this means an engine teardown.

Or add a turbocharger!

[race911]

Well since everyone else here is commenting from out of state (hi local neighbor), be extremely aware of the cat/air pump/EGR you'll need to get the car smogged.

What did the most for me on my old '79 was a 7:31 ring and pinion.

Competition-wise, engine performance enhancements are the last thing you need.

[flat6pilot]

My SC engine upgrades were:

Bitz Racing EFI conversion: $2000 (www.bitzracing.com, Tony is AWESOME support)

1 5/8" European Racing Headers: $700 (http://www.dartauto.com/european-racing-headers-porsche-911-c-73.html)

M&K 2 in 2 out Exhaust: $700 (Pelicanparts, Ben at M&K ROCKS!)

MSD 6AL-2 Ignition: $260

I haven't dyno'd it yet, but my guess is about 20-25hp increase(?), plus very responsive throttle, laptop tunable and great sound.

How long do you Californians have to deal with smog on your older cars? Forever??

-Kyle

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[fredmeister]

Your original question was improving engine performance with simple changes. The PMO throttle bodies look great but he is running an add in Panorama selling his bizniz so he may be going under, not sure, so be careful with a future purchase. That is a shame because anyone that goes out and starts a bizniz providing improved Porsche performance components deserves a big applause. Air filter changes alone ot the CIS is a waste of money the paper filter from Porsche is fine.

If going to his throttle bodies and a cheap FI system, you should see good improvement in power and defintiely great throttle response improvement. The next hindrence in performance is going to be the stock 911SC camshaft which is very mild in terms of valve overlap and to some degree lift which was made that way to allow CIS to run properly.

As far as transmission regearing, that is a great choice and will give you most bang for the buck in terms of acceleration, at the expense of higher engine speeds during cruise and daily transport. Probably effect the gas mileage too.
At least be aware that you picked a great car to start from as the 1978, 1979 911SC engine came stock with the large diameter ports and intake runners on the CIS system which are better for performance improvements in airflow than the later cars with smaller tubes and ports. Plus they came with no catalytic converter either.
One thing about autocross and DE track days since you mentioned it. Autocross set up is way different than setup for track days. Your 911 will understeer badly at low speeds like autocross and likely you will need to disconnect the front swaybar to get the rear end to turn for you. Just a different approach to getting the car to perform well at both styles of event. I found that it was not near as much fun as track days and DE events.