Need more power! Arh-arh-arh!

porsche_virus · porsche_virus's Garage

Anybody have ideas for "bolt-on" power for my 1974 911? It's a stock 2.7, CIS, and so far I've only added a K&N filter, Magnacore wires, Bosch +4 plugs, and a high-output coil. It runs great and strong, but my friend is about to pickup a '74 Carerra with a 3.0 crammed into it, and I want to be able to keep up with him. I've looked all over the internet for high-flow mufflers but can't find anything prior to '75. Is that because the stock exhaust is good enough and shouldn't be tampered with...or that muffler manufacturers don't go back that far? I'd really like to go Turbo, but don't want to blow that kind of money just yet.

kc

Here's a pic of what I've got to work with...
BTW, should I cut off some of the plastic on the airbox inlet? I've seen lots of other pics of later P-cars with much shorter inlets.

Chuck Moreland · 09-09-2002, 09:27 PM

You can get "sport" style mufflers that will give you a little boost in power. I assume you have the original early style heat exchangers that came on '74s. They work well.

If you want to extract any significant performance gains from that motor (short of going turbo) you will need to change out the intake system and the cams. I would suggest popping on a set of webers and E or S cams.

You won't see any gains by shortening the intake snorkle.

CamB · CamB's Garage

"I would suggest popping on a set of webers and E or S cams."

Which unfortunately also means new pistons with deep enough cutouts for the greater valve lift of those cams. From your position, meaningful horsepower increases aren't cheap...

You could investigate a twin-pipe sport muffler (loud) or a Flaumeister for a few extra horsepower.

The shorter intake you have seen is on the SC engine. I don't know why it is shorter, I just know it is.

If it is a 2.7 you have ~150hp, so the Carrera with the 3.0 is probably going to hand your ass to you in a straight line. Better learn to drive better than him in the twisties!

Kemo · 09-10-2002, 05:43 AM

ive read some bad things about non-stock coils...

You can always reduce the weight of your car.

porsche_virus · porsche_virus's Garage

Heya...so how hard is it to replace the CIS with Weber carbs, and why didn't they leave them on for the '74 and up models if they provide more performance?

kc

Kemo · 09-10-2002, 10:23 AM

Fuel injection systems are better suited for fuel ecomomy and emmissions. Probably easier to maintain as well...if there are no air leaks!

Im having a hell of a time working out my cold start problem...i have a feeling it will be the warm up regulator which is one of the expensive parts...oh well. If i could afford some PMO carbs...i would definitely get some.