race911

It did? So in '80 the US cars went from (nominal) 8.5:1 to 9.3:1, with the intake runners/ports coming back down to the "2.7L" size of 35mm, from 39mm. Cam timing was also slightly different. (ROW '80- engines were 9.8:1, and kept the larger runners.)

I've assembled all manner of 3.0 engines, with every combination of parts imaginable, and there really isn't much of a difference. Granted, no dyno testing back then in the stone age.......... But even pre-data acquisition, I was pretty diligent on keeping notes on whatever engine/transaxle combo I personally ran. The 3.5L CIS Frankenengine I built one time was the only one that masked the plenum effect of the CIS. 964 cams maybe masked it a little on a 9.8:1 3.0 with a good exhaust.

The easiest way to really see how the stock internals actually work pretty well is to (old school) bolt on Webers, usually 40s for a stock engine, or (today) throttle bodies with an engine management system. Ultimately, but it's mainly an "out think the rules guys" is the GT3 intake on throttle bodies with Motec that Gamroth sells for Spec 911 engines. Fully stock 9.3:1 3.0s with 1 5/8" headers making nearly 270HP.

Reiver

I'm guessing on the 200 hp. Just what I've been told by P mechanics what the 'unchoked' exhaust should be/do....I can feel the torque dif.
That's nice HP for a basically stock 3.0 with that set up.
What does the GT3 intake on throttle bodies with Motec with 1 5/8 do to the power curve? Is it gradual or all on/off?

race911

I've not driven one, but I suspect it's not noticeably different than a 46IDA equipped variant which won the Spec 911 class at Rennsport Reunion last October. (It's actually my old chassis, which my friend has been campaigning in PRC, PCA Club Racing, and SCCA for the past several years.)

Video:

Reiver

Yeah, found their site...Rothsport Racing...that would be the low butterfly FI system....looks very well made and straightforward. 270 HP in a lightened SC would be just right.

race911

Cost is about what the average SC is worth right now.

What's magic about 20% more power on a street car that has a perfectly acceptable power-to-weight ratio? Over the weekend at Laguna, maybe I get 2-3 mph more terminal speed up the front straight going into the braking zone for T2 with the 993RS, versus the old stock class RS America club racer that was 50+ hp short. Conversely, a GT3RS pulls me about 4 car lengths up the front straight at Thunderhill, most of which I get back by the time we've put the power down before the apex of T1.

Reiver

Knew it would be expensive but not that expensive....have a friend that races Porsches and other cars in his collection, breaks them then builds another. Next visit he said I can take whatever I want off of his not running Porsches (5) so maybe I'll get lucky.
Ronnie, that 260 HP does sound like fun.

Ed Hughes

You don't want to know what my 260-270HP cost, with my labor. I know I don't.
But, it was an experience I loved.

Reiver

Ed. I'm with you. If I ever sat down and tried to estimate what I've spent on my 'fun ' cars over the years I'd probably go sideways (or my wife would do it for me).
I've put over 4k miles on the car since mid November and really enjoy the 911's personality....I suspect at some point I'll do some HP hunting myself.

race911

And the 300-320hp in the 993RS was $30K for the previous owner (built to perfection by Mr. Weiner himself). Picking it up for what I did, and NOT having to build that damn thing myself, was an experience I loved.

(Throwing this totally OT, here's some of the only video I got from Laguna last Saturday--rain/student load/dead Hoosiers/dead RA1s/younameit all conspired.


)

Bottom line though is that everything you can imagine has been done to these engines over the past 40+ years. And absent a pretty extensive effort into the intake and exhaust as mentioned above, nothing really matters all that much.

race911

Oh, skip the first four minutes of the above. Was all to do with waiting for another guy to catch up, which he didn't.

Peter Zimmermann

SC cams are so mild that you really can't do a whole lot. Here in CA you can't do anything, if you want to pass an bi-annual smog test, except the labor involved to remove the cat (replace with a Carrera pre-muffler), or replace the entire exhaust with SSIs and a different muffler. The characteristics of USA, stock, '78/79 cars is very different from '80-83 models. The early cars can have a slightly stronger feeling top end, while the Lambda cars feel more lively in town, from stop lights, etc. The "sweet spot" can vary 1,000 revs from car to car, and then you throw in incorrectly timed cams, incorrect CO% settings, bad plug wires, etc., and you can really end up with a mixed bag. My '82, dead stock and perfectly tuned, is pretty lively, as it should be, above about 3200 rpm, but it will never feel like a proper '71 S, which will absolutely fly from 4800-7200 revs!

Reiver

I'll get to drive a few Porsches in a few months for comparison so that will be fun. One is a comp model a friend has.
I hear you saying that if I want 250 HP then it would be a better idea to get a dif model than the 3.0.
I'll have a better idea what I really want with more 911 experience....
They do have great personality.

rusnak

Never add up your receipts!!!

Usable hp where it counts is the key. That is the fun part of driving a 911.

Tom Tweed

My stock Euro 3.0SC Type 930/10 engine with backdated exhaust made 197 RWHP on the dyno. The torque curve is very flat--from 4,000-5500 RPM it is making 180-190 ft.-lbs. consistently, so that is where I would say the "sweet spot" is. Over 6500RPM it starts to "run out of breath" with the CIS cams and torque drops off below 160 ft.-lbs. rather quickly.

Since the factory rated this engine at 204 DIN HP at the flywheel, and a 15% drivetrain loss would put my engine at about 227 at the flywheel, the backdated exhaust is definitely helping output substantially.

TT

GothingNC

Mine kicks in above 3K

9.7 Compression pistons
SSI's-Dansk sport muffler
Intake ports and runners ported and blended to 36MM
Elgin 330 Cams

184HP at the wheels.