200+ h.p. from a 3.0 cis?
 

1978 3.0 ltr. CIS eng. number 930/04

trying to do this on a budget

what im doing is building a track car and want to up h.p. this is what i have in mind. keep in mind this car is not street legal

im going to run headers not sure on size was thinking 1"5/8 ? but not sure.

wondering what the best cam would be for the CIS pistons, and how much cam i can go with CIS? i also have a set of webers that i can run if need be.

i have carrera tensioners. pulled the motor due to a lower end rattle looks like a gold miner in the case. before the engine pull i had done a compression test and it was very even i cant find my tablet with numbers but good as i recall. the leak down was less than 5% across the board and as i recall the engine was pretty cool at the time.

anyways fire away at what to and not to do. open to ideas and want to get over 200 h.p. if possible.

thanks ed

Change pistons and cams then go with the webbers. Should be able to get 200+ reliable and safe power.

Just going to a euro 9.8:1 CIS piston will get you most of the way there if you did not want to ditch your CIS... just make sure you get good gas as 9.8:1 is about your limit for single plug on street gas... some say its even too much for single plug.

As for budget... those 9.8:1 piston sets are getting rare and expensive, but changing pistons, cams, and intake will probably be more expensive in the end... you'll get more out of it though so on a $/HP increase it will be cheaper I think.

Best regards,

Michael

First,...with CIS, you are pretty well limited to around 200 HP on a 3.0. You'll do better by making it a 3.2 w/964 cams. :)

For quick bolt-ons that yield 200+ HP, install a set of 40mm carbs, 964 cams (retaining CIS pistons), and a pair of good 1.5" headers. 1 5/8" is too big for that application.

Ultimately, your net power will depend on many variables such as intake system, cam timing, fuel, exhaust system and how well everything is put together. :) :)

thanks Micheal

that sounds good but i think i want to retain stock pistons for now. as this is not the motor that i will be running will end up with a 3.2 OR bigger in the end. so this motor will most likely be a donor for a street car one day.

Steve

i like using the idea of using the stock CIS piston and cylinders, as for the 964 cams would these work in the future on a street car with CIS?. Not really a problem just have a car that will need a 3.0 in the future and was wondering about that. i have the webers and a set of 2.2 intakes that im pretty sure haven't checked but wont work.

so i need some 1 1/2 headers what muffler system would you suggest i was thinking just a set of megaphones?

im in the process of collecting parts so im listening and taking everything into consideration.

thanks ed

964 cams will work on any CIS engine or 3.2 engine. Your intake manifolds will be to small. You can grind them out to match your ports. Carbs need to be rejeted. Megaphones work great with that engine, you'll need earplugs though.

-Andy

so after installing 964 cams im done racing the motor i can put CIS back on top and run it in a street car?

yea mega phones are loud but cheap and gets the job done. thanks for your response as all this info is very helpfull.

is there enough meterial in the carb base plates to hog them out to the big port 3.0 that i have?

thanks ed

964 cams
 

another pelican has a set of 964 cams with looks like 4 bearing or journal sufaces.

my question with out pulling my motor apart yet is is my 1978 motor a 4 or 3 journal ? i here alot as im searching about these differences.

ill try and get pics for you guys again thanks for the help.

thanks ed

Your '78 motor has 4-bearing cams and housings.

Remember, if you use OEM 964 cams, the PS drive on the right side cam needs to be machined off.

will these work? is there a better cam and what about some of the efi conversions out there some very budget minded ones for less than carbs. i cant think of the link at the moment but it was around 1700.00

thanks ed


http://forums.pelicanparts.com/porsche-911-used-parts-sale-wanted/432377-964-cams.html?highlight=964+cams

Better yet, IF you already have CIS cams, you can have them reground by John Dougherty to 964 profile for less money than the ones you show here. The added advantage is you will be sure to start from like new lobes.

Aurel

yep thats the route im going to take.

ed