llthomas

Hi - My 78 SC is in the shop for a rebuild. We decided to get more horsepower if we had to do this anyway - so after talking to a number of people and reading all of these forums, we decided to go with Bruce Anderson's suggestion and put 3.2 cylinders, 98mm pistons with a 9.8-1 ratio, a euro fuel distributer( Is the WUR needed?),964 cams, and to backdate the exhaust.
Today my mechanic comes up with a new senario - I won't like the 964 cams, we need to use a 20-21 grind(?), zero cylinders, and a ratio of 9.5 to one is better, and then backdate the exhaust. Not needed to do anything with the fuel distributer.
So back to the drawing board, I call rennsport, ebs racing, outfits in L.A., IA, TX, and Nevada. And I get that many mnore opinions that range from just leave it stock it is not worth it - to spend $15,000 and throw a 3.6 in there.
I have read all of the threads here and everywhere else, does anyone really know what they are talking about? HELP. Isn't there one true combination that works as expected? This is a street car that will be driven hard and fast, but longevity is a must, and race gas is out as are carbs. Give me your vote. Thanks

TonyG

Install 20/21 cams, 46mm PMO's (with short velocity stacks) and ITC air cleaners , SSI headers and a MB911 2in/2out muffler.

Have the distributor rebuilt, recurved, and converted to full mechanical advance.

Then sit back and enjoy about a 70HP increase in power with a bullet proof engine....

TonyG

earlyapex

You may be surprised how close a 3.0 L rebuild will cost when you add on the cost of 3.2 P&C, PMO's, distributer, cams, etc. It get darn close to what a good 3.6 L transplant costs. And thus the dilemma.

I vote for keeping it a 3.0 L and massaging everything else. That's the route I'll be going at the end of the track season.

Peter Zimmermann

Don't be too hard on those mechanics! Check out F1, as an example, and look at how many aero variations each team's wind tunnel experts came up with! Anyway, personally, back in '98, I put a set of 3.2L Max Moritz Mahles (from Andial) in my '81 SC. I timed the cams to Euro spec (0.9-1.1) after dial indicating intake cyls #1 & 4 to the exact adjustment spec. A perfect valve job with 3-angle seats was included, a test pipe replaced the cat, and the CO% was set at about 1.7. That car hauled, and I never drove a 3.2 with equal throttle response and quickness. If smog requirements in your state are lax you can even go one better - use SSIs with a sport muffler. I've never used a "Monty" muffler but Steve Weiner endorses them, so you can take that to the bank (although I'm not sure if the Monty works on an SC).
Pete

2002M3Drew

I have the SSis and the Monty, both courtesy of Steve Weiner at Rennsport, on my otherwise-stock 83 SC motor, and they alone make a huge difference. I was at Lime Rock with my local PCA chapter one weekend without the exhaust changes, changed out the exhaust that week, and then ran the following weekend on the long course at Pocono (a must faster track than Lime Rock), and I was catching and passing cars that a week before I was not. (One 964 actually asked if I had added a turbo!) On paper, I'm sure the gains are pretty decent, but in real world drivability and speed characteristics, the backdated exhaust and Monty really shine. The Monty is a 2 into 1, by the way, and is plenty loud, at least from outside the car. I'm getting many compliments on the tone.

llthomas

So today I had to make a choice - but women have a hard time with this especially with so many! So I said the JE's are ok, a 9.5:1 is probably a safe bet compared to 9.8:1. 98mm with a zero cylinder is fine, and 964 grind. The exhaust is still up in the air - I like the SSI's - and I want the power but the broken pieces of metal in the muffler sound is not appealing - so what muffler (if there is one), will be a deeper throaty sound?

TonyG

>>>will be a deeper throaty sound?<<<

Dansk sport muffler (2 in, 1 out).

www.performanceproducts.com has them.

TonyG

Mysterytrain

I went down this path last year and did a spare no expense rebuild of my 78sc. Bumped it up to 3.2 with JE pistons, mahle jugs, 964 cams. Stayed with the CIS but rebuilt it. Replaced, valves, springs, oil cooler, oil pump etc. compression is 9.5:1. Went with SSI's and a Dansk 2/1 { ok, but I'm not in love with the dansk} This car is a hoot to drive. I have it registered in NJ as a collector car so I don't need to have the emissions tested..plus I can always reinstall the stock exhaust if I want the car as a daily driver. The build wasn't cheap especially when you figure in all the 'while you are in there' stuff ..alt, starter, axles, brakes but I feel I have a very reliable car again that I can drive anywhere.

LaughaC

So the 964 cams do work with CIS? Any idle problems?

Mysterytrain

The 964 cams work fine and were recommended by EBS because I wanted to stick with the CIS. I have the Dansk 2 in/1 out muffler that is OK, I guess. It sounds different then the original system and I'm not sure if thats because of the 'free flow' SSI's or the Dansk. I still want more low and throaty rumble. The project was pricey but my 200k motor was going to need lots of new parts anyway, so going to 3.2 wan't that big of an issue. It was the new oil pump, oil cooler, chains, sprockets, rockers, springs, valves..etc, etc. My logic in keeping the 3.0/3.2 short stroke rather then a 3.6 transplant was two fold. First off, I wanted something very reliable and most 3.6 engines are also approaching the need for some serious work. The donor would no doubt be a crap shoot..ok for a track car but not for a streeter. The other point which might seem odd for some was..back when I was looking for a 356 project car I would find car after car with the wrong engine. This really bothered me. So, the 3.2 bump up allowed me to keep things kinda stock in apperance and still have a motor that goes like hell.

LaughaC

Congrats. That sounds like good, proven advice. The "Porsche 911 Performance Handbook" says CIS is good up to 400 hp, so I'm not surprised it can handle the 3.2 The CIS is also reliable and provides much better mileage than carbs. Any estimates on the hp or torque output of your 3.2?

A "motor that goes like hell..." is always on my want list. Mine is a daily driver too, and I have a healthy 2.7 with SSI and 2 into 1 performance muffler. My next step is likely to be cams if you think the 964 cam upgrade is worth pulling everything apart. I've changed cams in every hot rod I've ever owned and it is definitely the biggest bang for the buck if the exhaust system is open. Most of my current power is from 3600-6400 and the motor builder tells me I have stock cams. Is the powerband any lower with the 964 cams? I need more torque from 2200-4000 if I can get it without sacrificing much peak hp.

I've also been told to try a supercharger, which sounds like the best plan on paper, but I'm unsure the CIS will map the fuel ratio accurately enough with positive air pressure. Until I find a proven case with a Paxton and a CIS I will leave the idea on paper.