Turbo SC project ?

[MarKoBrow]

I just left friends shop and was discussing putting a turbo on a stock SC engine with Megasquirt and EDIS ignition. I am pretty familiar with the Megasquirt and the EDIS, what I am not clear about is whether the stock Alusil Cylinder and Cast CIS piston will hold up under boost can someone clear this up for me? I have heard so much talk about nikasil and turbo pistons. I also want to add that the engine has been twin plugged by it's previous owner but the the lower set of plugs where never wired ( I don't know why before I am asked)

[copbait73]

Before all the 930 Turbos guys get on to tell you it's not advisable I'll say anything is possible, however one must consider the return for your time and cash. Can you do it all yourself? Are you resourceful in collecting the required hardware?

Assuming you turbo a stock N.A. 3.0L you will need to keep the boost very low to deal with the relatively high fixed compression ratio. With this very low boost you will see maybe 30HP. Above that figure you are pushing the limits of cast pistons, plastic CIS manifolding and existing cooling. In the 80s here were kits to do this.

If you rebuild this motor into one approaching Turbo 3.0/3.3 L configuration then you get into a slippery slope of cost vs. HP payback that many encounter in their quest for more HP. Unless you are very mechanically inclined, very resourceful, have the tools and can do it all yourself I think the best answer to your inquiry is to install a factory 930 turbo motor in your car.

As in all things one must set firm realistic goals then proceed accordingly.

[sjf911]

It is doable and has been done by more than a few of us. Using a Carrera 3.2 intake makes the project relatively easy. Durability? Depends on your horsepower desires and health of your starting components. You will need to limit boost compared to a stock 930 unless you want to swap out to lower compression pistons, but having infinite control of timing and fueling is a huge plus.

[MarKoBrow]

Thank you both for the quick reply. I can answer that he intends on doing his own work, he is a great motorcycle mechanic and very accomplished machinist, in fact I must be honest I was the one questioning if this would work or not.

[iamchappy]

Good classic read here on it,
911SC Turbo

if you wish to keep it simple the Euro intake setup for sale on the forum would be a good start. The Sc engine with it's 8.5 compression boosted to 8lbs can make up to 350hp.

The 3.0 Sc engine makes for a great little turbo platform. I ran mine at 8lbs using the stock SC CIS intake but had a 7th injector for enrichment and used an MSD boost timing retard ignition for years without any problems. The Euro CIS setup would handle the fueling and make for an easy install just keep the boost under 9lbs.

[mb911]

mine is a converted 81-3.0 sc engine. I went with stock alusil components the 1st time. the reason I had to do it a second time was the boost signal hose melted on the heat exchanger and over boosted. it did not like that. I have provided 20 plus kits for folks since then and I now have a 3.2 short stoke turbo with a k27-7200 and 993 heat exchanger with our M&K split volute twin waste gate system with mega squirt running the fuel and a12 plug dizzy running the spark though EDIS would be nice I like the looks of the dizzy. I had countless thread on this forum and the engine rebuild forum. Its easy and well worth it. though a bit of a learning curve it will pay off as if you like the car why sell it and by a 930 when you can build your own version






just a few quick pics of my car

[911nut]

Do a user search for user name RFNG. The late Richard Fong was trying to get a turbo kit for the SC off the ground but couldn't get enough people interested. He put a simple system together that worked fairly well.

[copbait73]

What stock 3.0L does he have? 8.5:1 or 9.3:1 C.R.?

[911nut]

Originally Posted by copbait73

What stock 3.0L does he have? 8.5:1 or 9.3:1 C.R.?

I believe it was 9.3:1. He was running about 5 lb. of boost without an intercooler.

[mb911]

same here and mine was 9.3:1

[copbait73]

Originally Posted by mb911

same here and mine was 9.3:1

OK, my comment was to a stock 3.0L CIS based motor, but I assumed 9.3:1 which was what I turboed at 5PSI also.

[RarlyL8]

The Late Richard Fong? What happened to Richard? We dropped out of touch some time ago but he was fairly active on the board a few years back.

I don't thing Ben listed a HP figure anywhere.

[copbait73]

Originally Posted by RarlyL8

The Late Richard Fong? What happened to Richard? We dropped out of touch some time ago but he was fairly active on the board a few years back.

I don't thing Ben listed a HP figure anywhere.

Thank you, the comment was not from Ben, I will correct.

[MarKoBrow]

There is a post elsewhere that say Richard Fong passed away

[jcc911]

FYI I am headed down the same path, and if you are looking for simple, Chappy is right, go for the 930 intake. This is route I am chosing after attempting the 3.2 intake but switched at the last minute.
There are a few 930 intakes on this board for a good price. The one I just saw for $800 with the airbox is a VERY good price.
The other, although slightly cheaper and no airbox, I would be cautious about b/c I have seen some complaints in dealing with the owner.

Copbait is also right in regards to the sourcing all of the required components. May of them can be purchased right off of the shelf, for a premium, but used stock parts are rare. Beleive me I have been seaching for the smallest parts for a long time.

It certainly is doable as many have done it. Just depends on how fast you want it done and how much you want to spend.

Contact Ben at M&K, he has some really nice Turbo conversion setups.

PS I beleive the C/R of my 78 3.0 is 8.5:1 and I am going to run the Alusils

[mb911]

Originally Posted by copbait73

OK, my comment was to a stock 3.0L CIS based motor, but I assumed 9.3:1 which was what I turboed at 5PSI also.

A 3.2 carrera with .6 bar will produce 327HP at the wheels I have a customers dyno sheet. this was v1 of my ssi system.

On a stock 3.0 with say a BAE kit on it with a t3t4 turbo will produce high 280ish HP on .5 bar. One of my friends has this setup and it has been dyno'd. His is a 78 sc euro so that should be 8.5:1 if memory serves.

copbait I did not see what you wrote as it was edited so I can't answer specifically.

I am happy to help however I can

[mb911]

oh and on a well tuned turbo setup you can expect 12-15hp for every PSI of boost

I also suggested to jcc911 that the 930 route is the easiest and this is the way I would have done it in hindsight for costs etc but my system developed beyond that anyhow.

Best of luck

[jcc911]

On a stock 3.0 with say a BAE kit on it with a t3t4 turbo will produce high 280ish HP on .5 bar. One of my friends has this setup and it has been dyno'd. His is a 78 sc euro so that should be 8.5:1 if memory serves.

Now that gets me very excited....

[copbait73]

Ok, if you look at what the factory delivered in 3.0L engines you had 180 HP N.A. and 260HP boosted to 11.8PSI. This is 6.8HP/one PSI manifold boost.

If you wish to take a 8.5:1 N.A. motor and simply lash up a turbo with little cost and some risk you should expect 210-220HP on pump gas. If you wish to start spending money to reinvent the wheel do that also. Turbos are great devices, they can give you just about any HP you wish. The F1 guys produced 15HP/CID, that equates to a 2700HP 3.0L.

See below effective compression ratio chart for suggested manifold pressure.

[911st]

Could sell the SC motor for $3500 and buy a 930 motor for about $7k.

Will be a lot less work and more valuable should you sell.

You are limited to HP with your SC trans. Have seen a trans & motor for in the $8k range.

A 930 motor has the potential for being smog leagal in in Ca if done right and the same or newer year. May not matter to you.