RickMcDonald

Hi. I'm new to forums, so please bear with me.

I have a 1980 911SC and though I really like the car, I want to get more power out of it. My son and I have come to the conclusion that 220-hp would be a good goal (though more obviously wouldn't be a bad thing!). Is it possible to get 220-hp from the 3.0L engine without significantly compromising reliability and/or drivability? If so, what's the best/cheapest way to go about doing that?

Thanks in advance!

r911

Throw away the intake, exhaust, muffler, heads and cams.

How much do you want to spend?

RickMcDonald

Not so much that I'll wish I bought a 964 Turbo (my ideal car) instead!

In all seriousness, less than $10,000. Less is better, but I know I'm dealing with a Porsche here, so I know modifying it won't be as cheap as, say, American Muscle might be.

Elephant Chuck

To maintain reliability and driveability, consider bumping displacement to 3.2 and adding SSIs with a good muffler and 964 cams. For $10K you might even be able to twin plug and bump compression.

Though there are hotter setups (carbs and S cams, etc), the above is a very streetable and reliable way to get to your goal.

Steve Weiner-Rennsport Systems

Rick:

Randy offered you sage & realistic advice,.....

To get a true 220 HP from a CIS-injected engine requires a serious infusion of $$$$. There are many ways to go about this depending on whether you wish to retain the CIS for smog compliance or not, but you'll not have ANY change from that $ 10K bill and its likely that you'll need more to do it right.

I'll leave you to do some research on your own but here are some examples:

3.0 engine with MFI/carb pistons & cylinders, "S" cams, 46mm PMO carbs, SSI heat exchangers and Monty Sport Muffler.

3.4 engine with 98mm P/C's, 964 cams, 964 twin-ignition, CIS fuel injection, SSI heat exchangers and Monty Sport Muffler.

Both configurations deliver 220+ HP and will feel TOTALLY different,.... Like people, engines have different personalities based on what state of tune and configuration they have and each person decides what is best for them.

Quite obviously, the final result will be determined by your budget.

Pedro356C

Hi Rick...sell the 1980 SC...add the $10k, you had as budget to reach 220hp, and buy a 1990 or 1991 964 with 247hp...no risks as far as reliablility and you get 27 hp as bonus and also a G50 tranny...

PS. The above advice is not applicable if you have some emotional attachment to the 1980SC!

RickMcDonald

Oh, I forgot to mention, I'm a mechanic so I get all my labor "for free" (sorta ) and basically just need to worry about parts. Problem is, I'm kinda new to Porsches so I don't have any idea which parts to get!

Thanks again for the advice everyone!

RickMcDonald

I do have a sort of attachment to the car. It has a great 930-look conversion done to it and I really like that. (I would post pictures, but I don't know how to upload to the gallery.) Plus, the suspension mods done by a previous owner make it drive great... except for the lack of power.

BTW, my son offered the same suggestion to buy a 964.

RickMcDonald

Pardon my ignorance, but what are SSIs?

Thanks!

RickMcDonald

Smog legality would definately be a plus since I live in California.

82Targa

SSI headers. Well, heat exchangers actually. If you don't care about heat in the car you can just put on headers. Earlier 911s (up to 74 if I am not mistaken) had well tuned headers. Changes were made to comply with emissions standards, and HP took a hit. SSIs get you back some of the HP lost.

Don't bother with 'Cat-bypass' tubes or high flow mufflers. The 911 exhaust system is already free flowing. Its the unequal length header tubes that costs you, and the SSIs fix this.

Steve Weiner-Rennsport Systems

Welll,......thats partially correct,...

I would caution one not to "tar everything with the same brush". Once again (like people), mufflers are NOT all the same and although the factory ones are darned good, some are better than others. Most so-called performance mufflers however, make more noise than additional power.

Now,....comparing the single inlet stock SC muffler with an OEM Leistritz dual inlet muffler is hardly a fair & valid comparison and thats the whole point of any exhaust upgrade for an SC. One gains usable torque and HP from 2500-6500 with a pair of '74 style 3-into-one heat exchangers (SSI's) and a matching dual-inlet muffler. Some aftermarket mufflers such as the Monty do perform better than the factory OEM ones, albeit with additional noise.

The SC's stock crossover exhaust plumbing that connects the right side cylinder bank to the outlet of the left side for the common cat & single inlet muffler is the main restriction and certainly wasn't Porsche's best effort,....

Smog compliance usually requires retaining these stock systems however many folks do a swap every 2 years between their stock and performance systems to enjoy the benefits of improved performance. In the case of the SC's 3.0 motor, when isn't going to partake of such a process, sometimes the best overall performance upgrade is the installation of a 3.6 from a 964 or 993.

Thats a whole 'nuther thing altogether,......

fixnprsh

I just had to swap out SSI's and the oil line for a customer for smog on their SC. If you cant DIY and/or you dont have the original exhaust and stuff, this can get expensive, I basicaly lent the customer my own cat and muffler and oil line, but the heat exchangers they had to source on thier own as 3.0 SC, 3.3 turbo and 3.2 carerra all have different port sizes and the heat exhangers dont interchange.

TAREK

This may sound stupid, but do turbo manifolds/exhaust from a 930 bolt on to the 3.0? and would that necessitate an overhaul of the CIS? since CR is only 8.5:1, could the pistons and rods handle...say...8-10 lbs of boost?

r911

You need to think and then post what direction you want to go with the car, and how many pennies you have. I note that you weren't so shocked by the price issues in the first few replies that you committed suicide...

It seems the 3.6 is out since you have the ability to do all labor yourself and that would just be a simple swap. But it would give you oodles of power and torque and be smog complaint.

If you get caught cheating on smog there could be very severe consequences. That said, if I lived in Redding (vs. LA or the Bay Area) I wouldn't be too worried about technical complaince. I'd try to make sure I didn't make the car real dirty, but I'd aim for a fairly clean powerful car even if it didn't match every reg.

For a street car in Redding you don't want headers. My first move if I kept that engine in would be an SSI with a Monty muffler, or maybe the one that Ben (mb911) on pelican makes. It is half the price and they all say it is well made and sounds good. There is no dyno data on it tho. The Monty is known not to lose any hp. I like the dual cow horn style...